CAM 701107

Interspinous and Interlaminar Stabilization/Distraction Devices (Spacers)

Category:Durable Medical Equipment   Last Reviewed:June 2019
Department(s):Medical Affairs   Next Review:June 2020
Original Date:January 2007    

Description: 
Interspinous and interlaminar implants (spacers) stabilize or distract the adjacent lamina and/or spinous processes and restrict extension to reduce pain in patients with lumbar spinal stenosis and neurogenic claudication. Interspinous spacers are small devices implanted between the vertebral spinous processes. After implantation, the device is opened or expanded to distract (open) the neural foramen and decompress the nerves. Interlaminar spacers are implanted midline between adjacent lamina and spinous processes to provide dynamic stabilization either following decompression surgery or as an alternative to decompression surgery.

The following conclusions are based on a review of the evidence, including, but not limited to, published evidence and clinical expert opinion, via BCBSA's Clinical Input Process.

For individuals who have spinal stenosis and no spondylolisthesis or grade 1 spondylolisthesis who receive an interspinous or interlaminar spacer as a stand-alone procedure, the evidence includes 2 randomized controlled trials of 2 spacers (Superion Indirect Decompression System, coflex interlaminar implant). Relevant outcomes are symptoms, functional outcomes, quality of life, and treatment-related morbidity. Overall, the use of interspinous or interlaminar distraction devices (spacers) as an alternative to spinal decompression has shown a high failure and complication rates. A pivotal trial compared the Superion Interspinous Spacer with the X-STOP (which is no longer marketed), without conservative care or standard surgery comparators. The trial reported significantly better outcomes with the Superion Interspinous Spacer on some measures. For example, the trial reported more than 80% of patients experienced improvements in certain quality of life outcome domains. Interpretation of this trial is limited by questions about the number of patients used to calculate success rates, the lack of efficacy of the comparator, and the lack of an appropriate control group treated by surgical decompression. The coflex interlaminar implant (formerly called the interspinous U) was compared with decompression in the multicenter, double-blind Foraminal Enlargement Lumbar Interspinous distraXion trial. Functional outcomes and pain levels were similar in the 2 groups at 1-year follow-up, but reoperation rates due to the absence of recovery were substantially higher with the coflex implant (29%) than with bony decompression (8%). For patients with 2-level surgery, the reoperation rate was 38% for coflex and 6% for bony decompression. At 2 years, reoperations due to the absence of recovery had been performed in 33% of the coflex group and 8% of the bony decompression group. The evidence is insufficient to determine the effects of the technology on health outcomes.

For individuals who have spinal stenosis and no spondylolisthesis or grade 1 spondylolisthesis who receive an interlaminar spacer with spinal decompression surgery, the evidence includes randomized controlled trials and nonrandomized comparative studies. Relevant outcomes are symptoms, functional outcomes, quality of life, and treatment-related morbidity. Use of the coflex interlaminar implant as a stabilizer after surgical decompression has been studied in 2 situations-as an adjunct to decompression compared with decompression alone (superiority) and as an alternative to spinal fusion after decompression (noninferiority). In a randomized controlled trial conducted in a patient population with moderate-to-severe lumbar spinal stenosis with significant back pain and up to grade 1 spondylolisthesis, there was no difference in the primary outcome measure, the Oswestry Disability Index (ODI), between the patients treated with coflex plus decompression vs. decompression alone. "Composite clinical success" (CCS), defined as a minimum 15-point improvement in ODI score, no reoperations, no device-related complications, no epidural steroid injections in the lumbar spine, and no persistent new or worsening sensory or motor deficit, was used to assess superiority. A greater proportion of patients who received coflex plus decompression instead of decompression alone achieved the composite endpoint. However, the superiority of coflex plus decompression is uncertain because the difference in the CCS was primarily driven by a greater proportion of patients in the control arm who received a secondary rescue epidural steroid injection. Because the trial was open-label, surgeons' decision to use epidural steroid injection could have been affected by their knowledge of the patient's treatment. Consequently, including this component in the composite clinical success measure might have overestimated the potential benefit of treatment. This bias could have been mitigated using protocol-mandated standard objective clinical criteria to guide decisions about secondary interventions and subsequent adjudication of these events by an independent blinded committee. For decompression with coflex vs decompression with spinal fusion, the pivotal randomized controlled trial, conducted in a patient population with spondylolisthesis no greater than grade 1 and significant back pain, showed that stabilization of decompression with the coflex implant was noninferior to decompression with spinal fusion for the composite clinical success measure. However, there is uncertainty about the net benefit of routinely adding spinal fusion to decompression in patients with no or low-grade spondylolisthesis. Therefore, demonstrating the noninferiority of coflex plus spinal decompression vs spinal decompression plus fusion, a comparator whose benefit on health outcomes is uncertain, makes it difficult to apply the results of the study. The evidence is insufficient to determine the effects of the technology on health outcomes.

Clinical input supplements and informs the interpretation of the published evidence. Clinical input respondents were mixed in the level of support of this indication. While some of the expert opinion supported a potential benefit in carefully selected individuals, other experts were not confident of a clinically meaningful benefit or use in generally accepted medical practice, citing long-term complications leading to removal of the device. Some clinical input suggested that spacers may have utility in patients who are high risk for general anesthesia. Consideration of existing studies as indirect evidence regarding the outcomes of using spacers in this subgroup is limited by substantial uncertainty regarding the balance of potential benefits and harms. The main source of uncertainty about the benefits versus risks of using coflex plus laminectomy in patients who are not able to have general anesthesia is whether revisions, removals, and other secondary surgical procedures can be conducted safely if they are needed. The evidence is insufficient to determine the effects of the technology on health outcomes.

Regulatory Status  
Three interspinous and interlaminar stabilization and distraction devices have been approved by Food Drug Administration (FDA) through the premarket approval (FDA product code: NQO) are summarized in Table 1.

Table 1. Interspinous and Interlaminar Stabilization/Distraction Devices With Premarket Approval 

Device Name

Manufacturer

Approval Date

PMA

X Stop Interspinous Process Decompression System

Medtronic Sofamor Danek

2005 (withdrawn 2015)

P040001

Coflex® Interlaminar Technology

Paradigm Spine

2012

P110008

Superion® Indirect Decompression System (previously Superion® Interspinous Spacer)

VertiFlex

2015

P14004

PMA: premarket approval.

The Superion® Indirect Decompression System (formerly InterSpinous Spacer) is indicated to treat skeletally mature patients suffering from pain, numbness, and/or cramping in the legs secondary to a diagnosis of moderate degenerative lumbar spinal stenosis, with or without grade 1 spondylolisthesis, confirmed by x-ray, magnetic resonance imaging, and/or computed tomography evidence of thickened ligamentum flavum, narrowed lateral recess, and/or central canal or foraminal narrowing. It is intended for patients with impaired physical function who experience relief in flexion from symptoms of leg/buttock/groin pain, numbness, and/or cramping, with or without back pain, and who have undergone at least 6 months of nonoperative treatment.

FDA lists the following contraindications to use of the Superion® Indirect Decompression System:

  • "An allergy to titanium or titanium alloy.
  • Spinal anatomy or disease that would prevent implantation of the device or cause the device to be unstable in situ, such as:
    • Instability of the lumbar spine, e.g., isthmic spondylolisthesis or degenerative spondylolisthesis greater than grade 1 (on a scale of 1 to 4)
    • An ankylosed segment at the affected level(s)
    • Fracture of the spinous process, pars interarticularis, or laminae (unilateral or bilateral);
    • Scoliosis (Cobb angle >10 degrees)
  • Cauda equina syndrome defined as neural compression causing neurogenic bladder or bowel dysfunction.
    • Diagnosis of severe osteoporosis, defined as bone mineral density (from DEXA [dual-energy x-ray absorptiometry] scan or equivalent method) in the spine or hip that is more than 2.5 S.D. below the mean of adult normal.
  • Active systemic infection, or infection localized to the site of implantation.
  • Prior fusion or decompression procedure at the index level.
  • Morbid obesity defined as a body mass index (BMI) greater than 40."

The coflex® Interlaminar Technology implant (Paradigm Spine) is a single-piece U-shaped titanium alloy dynamic stabilization device with pairs of wings that surround the superior and inferior spinous processes. The coflex® (previously called the Interspinous U) is indicated for use in 1- or 2-level lumbar stenosis from the L1 to L5 vertebrae in skeletally mature patients with at least moderate impairment in function, who experience relief in flexion from their symptoms of leg/buttocks/groin pain, with or without back pain, and who have undergone at least 6 months of nonoperative treatment. The coflex® "is intended to be implanted midline between adjacent lamina of 1 or 2 contiguous lumbar motion segments. Interlaminar stabilization is performed after decompression of stenosis at the affected level(s)."

FDA lists the following contraindications to use of the coflex®: 

  • "Prior fusion or decompressive laminectomy at any index lumbar level.
  • Radiographically compromised vertebral bodies at any lumbar level(s) caused by current or past trauma or tumor (e.g., compression fracture).
  • Severe facet hypertrophy that requires extensive bone removal which would cause instability.
  • Grade II or greater spondylolisthesis.
  • Isthmic spondylolisthesis or spondylolysis (pars fracture).
  • Degenerative lumbar scoliosis (Cobb angle greater than 25°).
  • Osteoporosis.
  • Back or leg pain of unknown etiology.
  • Axial back pain only, with no leg, buttock, or groin pain.
  • Morbid obesity defined as a body mass index > 40.
  • Active or chronic infection - systemic or local.
  • Known allergy to titanium alloys or MR [magnetic resonance] contrast agents.
    • Cauda equina syndrome defined as neural compression causing neurogenic bowel or bladder dysfunction."

The FDA labeling also contains multiple precautions and the following warning: "Data has demonstrated that spinous process fractures can occur with coflex® implantation."

At the time of approval, FDA requested additional postmarketing studies to provide longer-term device performance and device performance under general conditions of use. The first was the 5-year follow-up of the pivotal investigational device exemption trial. The second was a multicenter trial with 230 patients in Germany who were followed for 5 years, comparing decompression alone with decompression plus coflex®. The third, a multicenter trial with 345 patients in the United States who were followed for 5 years, compared decompression alone with decompression plus coflex®.27 FDA product code: NQO.

Related Policies
701120 Facet Arthroplasty
701138 Interspinous Fixation (Fusion) Devices

Policy:
The Coflex device is considered MEDICALLY NECESSARY as a treatment of neurogenic intermittent claudication and/or spinal stenosis resulting in leg/buttock/groin pain, with or without back pain, or when used as a stabilization device following decompressive surgery. They may be considered useful therapeutic options for patients meeting specified patient selection criteria.

All other interspinous/interlaminar distraction devices are considered INVESTIGATIONAL. 

NOTE: Vertebral body replacement spacers (e.g., AVS AL PEEK Spacer) are considered MEDICALLY NECESSARY for vertebral body replacement used in spine surgery for persons with a collapsed, damaged or unstable vertebral body resected or excised during total and partial vertbrectomy procedures due to tumor or traums. Vertebral  body replacement with PEEK cages should NOT be confused with interspinous distraction devices (spacers) (e.g., X-stop).

Policy Guidelines
Inclusions (must meet all):

  • Patients age 40+ suffering from (intermittent neurogenic claudication) secondary to a confirmed diagnosis of lumbar spinal stenosis.
  • The patient must have a history of moderately impaired physical function with demonstrated relief when in flexion from their symptoms of leg/buttock/groin pain, with or without back pain; and
  • Patients must have undergone 6 months of non-operative conservative treatment including non-steroidal therapy, comprehensive physical therapy, and epidural injection series prior to be considered for surgery.

Exclusions:

  • Allergic to titanium or titanium alloy;
  • Spinal anatomy or disease that would prevent implant of the device or cause the device to be unstable in situ, such as significant instability of the lumbar spine, e.g., isthmic spondylolisthesis or degenerative spondylolisthesis greater than grade 1.0 (on a scale of 1 to 4); an ankylosed segment at the affected level(s); acute fracture of the spinous process or pars interarticularis;
  • Prior fusion or decompressive laminectomy at any index lumbar level;
  • Radiographically compromised vertebral bodies at any lumbar level(s) caused by current or past trauma or tumor (e.g., compression fracture);
  • Severe facet hypertrophy that requires extensive bone removal which would cause instability;
  • Significant scoliosis (Cobb angle greater than 25 degrees);
  • Grade II or greater spondylolisthesis;
  • Isthmic spondylolisthesis or spondylolysis (pars fracture);
  • Cauda equina syndrome defined as neural compression causing neurogenic bowel or bladder dysfunction;
  • Diagnosis of severe osteoporosis (T score of <-1.0 [WHO definition of osteopenia]).
  • Active systemic infection or infection localized at the site of implantation;
  • Body mass index (BMI) > 40kg/m2;
  • Back or leg pain of unknown etiology;
  • Axial back pain only, with no leg, buttock, or groin pain;
  • Active or chronic infection—systemic or local; 

Benefit Application:
BlueCard®/National Account Issues
State or federal mandates (e.g., FEP) may dictate that all FDA-approved devices may not be considered investigational, and thus, these devices may be assessed only on the basis of their medical necessity.
 

Rationale
The following conclusions are based on a review of the evidence, including, but not limited to, published evidence and clinical expert opinion, via BCBSA's Clinical Input Process.

Evidence reviews assess the clinical evidence to determine whether the use of a technology improves the net health outcome. Broadly defined, health outcomes are length of life, quality of life, and ability to function---including benefits and harms. Every clinical condition has specific outcomes that are important to patients and to managing the course of that condition. Validated outcome measures are necessary to ascertain whether a condition improves or worsens; and whether the magnitude of that change is clinically significant. The net health outcome is a balance of benefits and harms.

To assess whether the evidence is sufficient to draw conclusions about the net health outcome of a technology, 2 domains are examined: the relevance and the quality and credibility. To be relevant, studies must represent one or more intended clinical uses of the technology in the intended population and compare an effective and appropriate alternative at a comparable intensity. For some conditions, the alternative will be supportive care or surveillance. The quality and credibility of the evidence depend on study design and conduct, minimizing bias and confounding that can generate incorrect findings. The randomized controlled trial (RCT) is preferred to assess efficacy; however, in some circumstances, nonrandomized studies may be adequate. RCTs are rarely large enough or long enough to capture less common adverse events and long-term effects. Other types of studies can be used for these purposes and to assess generalizability to broader clinical populations and settings of clinical practice.

The literature is dominated by reports from non-U.S. centers evaluating devices not approved by the U.S. Food and Drug Administration (FDA), although a number of them are in trials at U.S. centers. As of April 2018, only the X-STOP, coflex, and Superion Interspinous Spacer (ISS) devices had received FDA approval for use in the United States. Manufacturing of the X-STOP device stopped in 2015. This review focuses on devices currently available for use in the United States.

Interspinous or Interlaminar Spacer as a Stand-Alone Treatment
Clinical Context and Therapy Purpose
The purpose of the interspinous or interlaminar spacer in patients with spinal stenosis and no spondylolisthesis or grade 1 spondylolisthesis is to provide a treatment option that is better than lumbar spinal decompression surgery. Although not tested in trials, another potential purpose could be to provide an alternative to conservative therapy in patients who are medically unsuitable for undergoing general anesthesia for more invasive lumbar surgery or nonsurgical conservative therapy.

The question addressed in this evidence review is: Does the use of an interspinous or interlaminar spacer in patients with spinal stenosis and no spondylolisthesis or grade 1 spondylolisthesis, when used as a stand-alone treatment, improve the net health outcome?

The following PICOTS were used to select literature to inform this review.

Patients
The relevant population of interest is patients with spinal stenosis and no spondylolisthesis or grade 1 spondylolisthesis.

Interventions
The treatment being considered is the placement of an interspinous or interlaminar spacer as a stand-alone treatment.

Comparators
The following practices are currently being used to treat with spinal stenosis with no spondylolisthesis or grade 1 spondylolisthesis: lumbar spinal decompression surgery and nonsurgical conservative therapy.

Outcomes
The general outcome of interest is whether placement of an interspinous or interlaminar spacer improves function as measured by a 15-point improvement in Oswestry Disability Index (ODI) scores. Other measures such as 36-Item Short-Form Health Survey to assess the quality of life, Zurich Claudication Questionnaire (ZCQ) also to assess quality of life for patients with lumbar spinal stenosis [LSS], and freedom from secondary interventions are also of interest to determine whether placement of an interspinous or interlaminar spacer improves the net health outcome. In addition, the adverse events of treatment need assessment.

Zurich Claudication Questionnaire (ZCQ)
The ZCQ was designed specifically for use in the evaluation of physical function in patients with lumbar spinal stenosis. Subscales of questionnaire may be used separately. For example, the 5-item Physical Function Scale is used primarily to evaluate walking capacity. These 5 items assess distance walked and activities of daily living involving walking. The Physical Function Scale has been used to assess walking as an outcome for surgical and nonsurgical treatment in patients with LSS.

The Zurich Claudication Questionnaire consists of three subscales:

  1. Symptom severity scale (questions I-VII) [further subdivided into pain domain (questions I-IV) and a neuro-ischemic domain (questions V-VII)]: Possible range of the score is 1 to 5.
  2. Physical function scale (questions VIII-XII): Possible range of scores is 1 to 4.
  3. Patient's satisfaction with treatment scale (questions XIII-XVIII): The range of the scale is 1 to 4.

Scoring Method / Interpretation
The result is expressed as a percentage of the maximum possible score. The score increases with worsening disability.

The ODI is a self-administered questionnaire used by clinicians and researchers to quantify disability for low back pain. The maximum score is 50. The Minimum Detectable Change (at 90% confidence) is 10 percentage points.

Interpretation of the ODI: 

  1. 0%-20%: Minimal disability: This group can cope with most living activities. Usually no treatment is indicated, apart from advice on lifting, sitting posture, physical fitness, and diet. In this group some patients have particular difficulty with sitting, and this may be important if their occupation is sedentary (e.g., a typist or truck driver).
  2. 20%-40% Moderate disability: This group experiences more pain and problems with sitting, lifting, and standing. Travel and social life are more difficult and they may well be off work. Personal care, sexual activity, and sleeping are not grossly affected, and the back condition can usually be managed by conservative means.
  3. 40%-60%: Severe disability: Pain remains the main problem in this group of patients, but travel, personal care, social life, sexual activity, and sleep are also affected. These patients require detailed investigation.
  4. 60%-80%: Crippled: Back pain impinges on all aspects of these patients' lives—both at home and at work—and positive intervention is required.
  5. 80%-100%: These patients would be bed-bound.

SF-12: 12-Item Short Form Survey
This health status survey is commonly used, brief (12 questions), and provides a description of the respondent's health. The 12-Item Short Form Health Survey (SF-12) is a measure of perceived health that describes the degree of general physical health status and mental health distress.  The SF-12 is a shorter alternative to the SF-36®. The SF-12 has at least one question from each of the SF-36's original eight domains. The SF-12 is scored on two summary scales, the Physical Component Summary (PCS) scale and the Mental Component Summary (MCS) scale, representing the physical and mental factors measured in the survey. Both scales are scored such that the adult population mean is 50, with a standard deviation of 10, and higher scores represent better function.

Visual Analog Pain Score (VAS)
The Visual Analog Scale [VAS] for pain is a continuous scale which depicts pain intensity along a line (usually 10cm (100 mm) long) that is anchored by two verbal descriptors, one for each symptom extreme. For pain intensity, the scale is most commonly anchored by "no pain" (score of 0) and "pain as bad as it could be" or "worst imaginable pain" (score of 100) on 100-mm scale. Typically, respondents are asked to report current pain intensity or pain intensity in the last 24 hours.

Timing
The window to judge treatment success is a minimum of 2 years post procedure.

Setting
The setting is inpatient care by an orthopedic surgeon or neurosurgeon.

Superion ISS Device vs X-STOP Device (Interspinous)
Patel et al (2015) reported on the results of a multicenter randomized noninferiority trial (10% margin) comparing the Superion ISS with the X-STOP.28 Trial characteristics and results are summarized in Tables 2 and 3. The primary outcome was a composite of clinically significant improvement in at least 1 of 3 ZCQ domain scores compared with baseline; freedom from reoperation, epidural steroid injection, nerve block, rhizotomy, or spinal cord stimulator; and freedom from a major implant or procedure-related complications.

The results at 2 years of follow-up indicated that the primary noninferiority end point was met, with a Bayesian posterior probability of 0.993. However, 111 (28%) patients (54 Superion ISS, 57 X-STOP) withdrew from the trial during follow-up because they received a protocol-defined secondary intervention. Modified intention-to-treat analysis showed similar levels of clinical success for leg pain, back pain, and ODI scores. Rates of complications and reoperations were similar between groups. Spinous process fractures, reported as asymptomatic, occurred in 16.4% of Superion ISS patients and 8.5% of X-STOP patients. Subsequently, long-term follow-up results were reported. At 3 years, 120 patients in the Superion ISS group and 129 in the X-STOP group remained (64% [249/391]). Of them, composite clinical success was achieved in 52.5% of patients in the Superion ISS group and 38.0% of the X-STOP group (p=0.023). The 36-month clinical outcomes were reported for 82 patients in the Superion ISS group and 76 patients in the X-STOP group (40% [158/391]). It is unclear from the reporting whether the remaining patients were lost to follow-up or were considered treatment failures and censored from the results. Also, trial interpretation is limited by questions about the efficacy of the comparator and lack of a control group treated with surgical decompression. At the 4-year and 5-year follow-ups, only data for the Superion arm were reported, which included data for 90% and 65% of originally randomized patients, respectively. Of these, success on at least 2 of 3 ZCQ domains was observed in 84% of patients at years 4 and 5. Nunley et al (2018) reported a decrease in opioid use (n=107) and improvement in quality of life (n=68) at 5 years, however, results were reported only for patients who had not undergone reoperation or revision, limiting interpretation of these results.29,30

The purpose of the gaps tables (see Tables 4 and 5) is to display notable gaps identified in each study. This information is synthesized as a summary of the body of evidence following each table and provides the conclusions on the sufficiency of the evidence supporting the position statement.

Table 2. Summary of Key RCT Characteristics

Study; Trial

Countries

Sites

Dates

Participants

Interventions

         

Active

Comparator

Patel et al (2015); 28 NCT00692276

U.S.

29

2008-2011

Patients with intermittent neurogenic claudication despite 6 mo of nonsurgical management (N=440)

Superion ISS (n=218)

X-STOP spacers (n=222)

RCT: randomized controlled trial.

Table 3. Results of Noninferiority Trials Comparing Superion With X-STOP

Study

Group

n

Success Rates

VAS Leg Paina

VAS Back Paina

ODI Scoresb

Spinous Process Fractures

Reoperation Rates

2 years

               

Patel et al (2015)31,28,31

Superion

136

75%c

76%

67%

63%

16.4%

44 (23.2%)

 

X-STOP

144

75%c

77%

68%

67%

8.5%

38 (18.9%)

3 years

               

Patel et al (2015)31

Superion

120

52.5%c

69/82

63/82

57/82

   
 

X-STOP

129

38.0%c

53/76

53/76

55/77

   

4 years

               

Nunley et al (2017)32

Superion

122

84.3%d

67/86

57/86

55/89

   

5 years

               

Nunley et al (2017)33

Superion

88

84%d

68/85

55/85

57/88

   

Values are n, %, or n (%).
ODI: Oswestry Disability Index; VAS: visual analog scale.
Percentage achieving at least a 20 mm improvement on a 100-mm VAS score.
b Percentage achieving at least a 15% improvement in ODI scores.
Composite outcome based on 4 components: improvement in 2 of 3 domains of the Zurich Claudication Questionnaire, no reoperations at the index level, no major implant/procedure-related complications, and no clinically significant confounding treatments.
d Clinical success on at least 2 of 3 Zurich Claudication Questionnaire domains.

Table 4. Relevance Gaps

Study

Populationa

Interventionb

Comparatorc

Outcomesd

Follow-Upe

Patel et al (2015)28

         

The evidence gaps stated in this table are those notable in the current review; this is not a comprehensive gaps assessment.
Population key: 1. Intended use population unclear; 2. Clinical context is unclear; 3. Study population is unclear; 4. Study population not representative of intended use
Intervention key: 1. Not clearly defined; 2. Version used unclear; 3. Delivery not similar intensity as comparator; 4. Not the intervention of interest.
c Comparator key: 1. Not clearly defined; 2. Not standard or optimal; 3. Delivery not similar intensity as intervention; 4. Not delivered effectively.
d Outcomes key: 1. Key health outcomes not addressed; 2. Physiologic measures, not validated surrogates; 3. No CONSORT reporting of harms; 4. Not establish and validated measurements; 5. Clinical significant difference not prespecified; 6. Clinical significant difference not supported.
e Follow-Up key: 1. Not sufficient duration for benefit; 2. Not sufficient duration for harms.

Table 5. Study Design and Conduct Gaps

Study

Allocationa

Blindingb

Selective Reportingc

Data Completenessd

Powere

Statisticalf

Patel et al(2015)28

3. Allocation concealment unclear

 

1. Not blinded to treatment assignment

2. Not blinded outcome assessment

3. Outcome assessed by treating physician

 

1. High loss to follow-up and/or missing data: 11% of patients not randomized; and data for 28% missing at 2 y; 36% at 3 y.

 

 

3. Unclear why a 10% noninferiority margin selected

 

The evidence gaps stated in this table are those notable in the current review; this is not a comprehensive gaps assessment.
Allocation key: 1. Participants not randomly allocated; 2. Allocation not concealed; 3. Allocation concealment unclear; 4. Inadequate control for selection bias.
Blinding key: 1. Not blinded to treatment assignment; 2. Not blinded outcome assessment; 3. Outcome assessed by treating physician.
c Selective Reporting key: 1. Not registered; 2. Evidence of selective reporting; 3. Evidence of selective publication.
d Data Completeness key: 1. High loss to follow-up or missing data; 2. Inadequate handling of missing data; 3. High number of crossovers; 4. Inadequate handling of crossovers; 5. Inappropriate exclusions; 6. Not intent to treat analysis (per protocol for noninferiority trials).
e Power key: 1. Power calculations not reported; 2. Power not calculated for primary outcome; 3. Power not based on clinically important difference.
f Statistical key: 1. Analysis is not appropriate for outcome type: (a) continuous; (b) binary; (c) time to event; 2. Analysis is not appropriate for multiple observations per patient; 3. Confidence intervals and/or p values not reported; 4. Comparative treatment effects not calculated.

coflex Device (Interlaminar)
A European, multicenter, randomized, double-blind trial (Foraminal Enlargement Lumbar Interspinous distraXion: FELIX) assessed the superiority of coflex (without bony decompression) over bony decompression in 159 patients who had intermittent neurogenic claudication due to LSS.32 The primary outcome at 8-week and 1-year follow-ups was the ZCQ score. The score increases with increasing disability. Trial characteristics and results are summarized in Tables 6 and 7. At 8 and 52 weeks, the primary outcome efficacy measure in the coflex arm was not superior to that for standard decompression. In addition, more coflex recipients required reoperation than the standard decompression patients at the 1- and 2-year follow-ups. Given the substantially higher frequency of reoperation in the absence of statistically significant improvements in the efficacy outcome, further summarization of study gaps was not done for this trial.

Table 6. Summary of Key RCT Characteristics

Study; Trial

Countries

Sites

Dates

Participants

Interventions

         

Active

Comparator

Moojen et al (2013)34;FELIX

Netherlands

5

2008-2011

Patients with intermittent neurogenic claudication due to lumbar stenosis with an indication for surgery (N=159)

Coflex (n=80)

Decompression (n=79)

RCT: randomized controlled trial.

Table 7. Summary of Key RCT Outcomes

Study; Trial

Proportions of Patients Achieving ZCQ Success,a (95% CI), %

Reoperations, n (%)

 

8 Weeks

52 Weeks

 

Moojen et al (2013; 2014)34,35; FELIX (1-y follow-up)

142

144

Not reported

Coflex

63 (51 to 73)

66 (54 to 74)

21 (29)

Decompression alone

72 (60 to 81)

69 (57 to 78)

6 (8)

Odds ratio (p)

0.73 (0.44)

0.90 (0.77)

p<0.001

Moojen et al (2015)36; FELIX (2-y follow-up)

145

Not reported

Coflex

69

23 (33)

Decompression alone

60

6 (8)

Odds ratio (p)

0.65 (0.20)

p<0.001

RCT: randomized controlled trial; ZCQ: Zurich Claudication Questionnaire.
Reductions in ZCQ scores were categorized as successful if at least 2 domain subscales were judged as "success." The ZCQ has 3 domains: symptoms severity, physical function, and patient's satisfaction. Success in the domains was defined as a decrease of at least 0.5 points on the symptom severity scale and on the physical function scale or a score of less than 2.5 on the patient's satisfaction subscale.

Section Summary: Interspinous or Interlaminar Spacer as Stand-Alone Treatment
The evidence for the Superion ISS for LSS includes a pivotal trial. This trial compared the Superion ISS with the X-STOP but did not include comparison groups for conservative treatment or standard surgery. The trial reported significantly better outcomes on some measures. For example, the percentage of patients experiencing improvements in certain quality of life outcome domains was reported at over 80%. However, this percentage was based on 40% of the original dataset. Interpretation of this trial is limited by uncertainty about a number of patients used to calculate success rates, the lack of efficacy of the comparator, and the lack of an appropriate control group treated by surgical decompression.

The coflex interlaminar implant was compared with decompression in the multicenter, double-blind FELIX trial. Functional outcomes and pain levels between the 2 groups at 1-year follow-up did not differ statistically but reoperation rates due to lack of recovery were statistically higher with the coflex implant (29%) compared with bony decompression (8%). It is not clear whether patients with reoperations were included in pain and function assessments; if they were, this would have decreased assessment scores at 1 year. For patients with 2-level surgery, the reoperation rate was 38% for coflex and 6% for bony decompression. At 2 years, reoperations due to the absence of recovery had been performed in 33% of the coflex group compared with 8% of the bony decompression group. This is an off-label use of the device. Use consistent with the Food and Drug Administration label is reviewed in the next section.

Interlaminar Stabilization Devices Used With Spinal Decompression Surgery
The largest group of patients with spinal stenosis is minimally symptomatic patients with mild back pain and no spinal instability. These patients are typically treated nonsurgically. At the other end of the spectrum are patients who have severe stenosis, dominant back pain, and grade 2 or higher spondylolisthesis or degenerative scoliosis >25 Cobb angle who require laminectomy plus spinal fusion.

Clinical Context and Therapy Purpose
The purpose of placement of an interlaminar spacer in patients with spinal stenosis and no spondylolisthesis or grade 1 spondylolisthesis is to provide a treatment option that is less invasive than lumbar spinal decompression surgery with fusion and more effective for back pain than lumbar spinal decompression surgery alone. Lumbar spinal stenosis has a broad clinical spectrum. Features that may affect the choice of the surgical procedure include the severity of leg pain, back pain, and instability; the presence of facet hypertrophy, diminished disc height, or deformity; the risk of general anesthesia, and the patient's preferences.10 The clinical feature that best distinguishes the target population for coflex is the severity of back pain, specifically, back pain that is worse than leg pain. The hypothesis underlying this use of coflex is that decompression alone, while effective for claudication and other symptoms of spinal stenosis, may be less effective for severe back pain than decompression plus a stabilizing procedure.

The question addressed in this evidence review is: Does the use of an interlaminar spacer in patients with spinal stenosis and no spondylolisthesis or grade 1 spondylolisthesis when used as an adjunct to spinal decompression improve the net health outcome?

The following PICOTS were used to select literature to inform this review.

Patients
Individuals with spinal stenosis, and no or grade 1 spondylolisthesis who have not responded to conservative treatment.

Interventions
The treatment being considered is the placement of an interlaminar spacer as an adjunct to spinal decompression.

Comparators
The comparators are lumbar spinal decompression with spinal fusion and lumbar spinal decompression surgery without fusion. Ideally, spinal decompression without fusion should be followed by additional nonsurgical treatment in patients who have persistent back symptoms.

Outcomes
The main outcomes of interest are (1) improvements in symptoms of spinal stenosis (eg, claudication, leg pain), (2) reductions in back pain, and (3) reductions in limitations on activities related to symptoms. Symptoms can be measured by scores of validated instruments such as the ODI and the ZCQ as well as visual analog scales (VAS) for back and leg pain. Other measures such as the 36-Item Short-Form Health Survey to assess the quality of life are relevant. Other key outcome measures are reoperations, including fusion procedures, and adverse events.

Timing
The window to judge treatment success is a minimum of 2 years post procedure.

Setting
The setting is inpatient care by an orthopedic surgeon or neurosurgeon.

coflex Device Plus Decompression vs Decompression Plus Posterolateral Fusion
FDA approved coflex on the basis of an open-labeled, randomized, multicenter, noninferiority trial (-10% noninferiority margin) that compared coflex plus decompression with decompression plus fusion in patients who had stenosis, significant back pain, and up to grade 1 spondylolisthesis.35-37 A total of 398 patients were randomized, of whom 322 were included in the per-protocol analysis. Of 215 coflex patients in the per-protocol analysis, 11 were lost to follow-up at the 2-year end point. In the fusion group, 3 of 107 were lost to follow-up. Results of long-term follow-up to 5 years were reported subsequently.37-41

Trial characteristics and results are summarized in Tables 8 and 9. Composite clinical success at 24 months showed that coflex was noninferior to posterolateral fusion (-10% noninferiority margin). Secondary effectiveness criteria, which included ZCQ score, VAS scores for leg and back pain, 12-Item Short-Form Health Survey scores, time to recovery, patient satisfaction, and several radiographic end points, tended to favor the coflex group. The percentages of device-related adverse events (5.6%) did not differ statistically between the 2 groups. Wound problems were more frequent in the coflex group (14% vs. 6.5%), but all of these resolved by 3 months. There was a 14% incidence of spinous process fractures in the coflex arm, which were reported to be mostly asymptomatic. The reported follow-up rates through 5 years were at least 85%.39

In the subset of patients with grade 1 spondylolisthesis (99 coflex patients and 51 fusion patients), there were no statistically significant differences between the coflex and fusion groups in ODI, VAS, and ZCQ scores after 2 years.42 In that analysis, 59 (62.8%) of 94 coflex patients and 30 (62.5%) of 48 fusion patients met the criteria for operative success. Reoperation rates were 14% in the coflex group and 6% in the fusion group (p=0.18). Outcomes for the subset of patients with no spondylolisthesis who were treated with the Coflex device at 1 or 2 levels have been reported.41 At 2 years, overall success was similar for patients treated with the coflex device at 1 or 2 levels (68.9% and 69.4%, respectively). At 60 months, the composite clinical success was achieved in 48.3% of 1 level and 60.9% of 2 level patients. Abjornson et al (2018) reported outcomes from the subgoup of patients without spondylolisthesis who received an interlaminar device with decompression, but comparison with decompression alone in this population has not been reported.43

Table 8. Summary of Key RCT Characteristics

Study; Trial

Countries

Sites

Dates

Participants

Interventions

         

Active

Comparator

Davis et al (2013)44; NCT00534235a

U.S.

21

2006-2008

Patients with spinal stenosis with up to grade 1 spondylolisthesis, 1 or 2 levels (N=344)

Coflex plus decompression (n=262)

Decompression plus fusion (n=136)

RCT: randomized controlled trial
Noninferiority study.

Table 9. Summary of Key RCT Outcomes

Study

CCSa

15-Point Improvement in ODI Score

No Secondary Surgical Intervention or
Lumbar Injection

No Secondary Surgical Intervention

No Secondary Lumbar Injection

2-year follow-up

         

Davis et al (2013)44

         

N

308

248

322

215

215

coflex

135 (66)

139 (86)

173 (81)

192 (89)

190 (88)

Fusion

104 (58)

66 (77)

89 (83)

99 (93)

94 (88)

%Δ (95% CI)

8.5b (-2.9 to 20.0)

9 (NR)

2 (NR)

-4 (NR)

0

3-year follow-up

         

Bae et al (2016)39

         

N

290

214

Unclear

NR

NR

Coflex

(62)

129 (90)

(76)

NR

NR

Fusion

(49)

53 (76)

(79)

NR

NR

%Δ (95% CI) or p

13.3 (1.1 to 25.5)

0.008

NR

NR

NR

4-year follow-up

         

Bae et al (2015)37

         

N

274

181

NR

NR

NR

coflex

106 (58)

106 (86)

NR

NR

NR

Fusion

42 (47)

42 (72)

NR

NR

NR

%Δ (95% CI) or p

10.9 (-1.6 to 23.5)

0.038

NR

NR

NR

5-year follow-up

         

Musacchio et al (2016)38

       

N

282

179

322

322

322

coflex

96 (50)

100 (81)

148 (69)

179 (83)

173 (81)

Fusion

40 (44)

41 (75)

71 (66)

89 (83)

82 (77)

%Δ (95% CI) or p

6.3 (NR); >0.90

>0.40

>0.70

>0.90

>0.40

Values are n or n (%.)
CCS: composite clinical success; CI: confidence interval; FU: follow-up; NR: not reported; ODI: Oswestry Disability Index (reported as mean score or percent with at least 15-point improvement).
a Composite clinical success was composed of a minimum 15-point improvement in ODI score, no reoperations, no device-related complications, no epidural steroid injections in the lumbar spine, and no persistent new or worsening sensory or motor deficit.
b The lower bound of Bayesian posterior credible interval for the device group difference in CCS was equal to -2.9%, which is within the prespecified noninferiority margin of -10%.

Tables 10 and 11 display notable gaps identified in each study. The major weakness in this trial was its use of lumbar spinal fusion as a comparator. Fusion after open decompression laminectomy is a more invasive procedure that requires longer operative time and has a potential for higher procedural and postsurgical complications. When the trial was conceived, decompression plus fusion was viewed the standard of care for patients with spinal stenosis with up to grade 1 spondylolisthesis and back pain; thus demonstrating noninferiority with a less invasive procedure such as coflex would be adequate to result in a net benefit in health outcomes. However, the role of fusion in the population of patients represented in the pivotal trial is uncertain, especially since the publication of the Swedish Spinal Stenosis Study (SSSS) and the Spinal Laminectomy versus Instrumented Pedicle Screw (SLIP), 2 RCTs comparing decompression alone with decompression plus spinal fusion that were published in 2016. As a consequence, results generated from a noninferiority trial using a comparator whose net benefit on health outcome is uncertain confounds meaningful interpretation of trial results. In addition, the underlying premise that patients with back pain and spinal stenosis do not respond well to decompression (alone or followed by nonsurgical treatments for back pain) has been challenged. For example, the ODI success rate for decompression alone in the European Study of Coflex And Decompression Alone trial43 was comparable to the ODI success rate for decompression plus fusion in the pivotal trial.

There are also gaps in the reporting of the pivotal trial. For example, a subgroup analysis of patients with grade 1 spondylolisthesis has been published. A similar analysis of the subgroup of patients with no spondylolisthesis would be helpful, as would results by treatment group for single and multilevel spondylolisthesis.

Another gap in the evidence, not listed in the gaps tables, is that other published evidence about the use of coflex as an alternative to fusion is sparse. The results of a single randomized trial do not always correspond with the rates of treatment response, complications, and reoperations in actual practice. Although thousands of coflex operations have been performed in the United States and elsewhere, there are few data on the performance of coflex plus decompression surgery other than in randomized trials. A retrospective cohort study (NCT03041896) undertaken by the manufacturer has not been reported, and a large registry of studies is not yet complete (NCT02457468).

Table 10. Relevance Gaps

Study; Trial

Populationa

Interventionb

Comparatorc

Outcomesd

Follow-Upe

Davis et al (2013)44; NCT00534235

   

2. Noninferiority to a comparator whose benefit is uncertain does not permit meaningful interpretation of the net benefit. This may be particularly problematic in the subgroup of patients with no spondylolisthesis.

   

The evidence gaps stated in this table are those notable in the current review; this is not a comprehensive gaps assessment.
Population key: 1. Intended use population unclear; 2. Clinical context is unclear; 3. Study population is unclear; 4. Study population not representative of intended use
Intervention key: 1. Not clearly defined; 2. Version used unclear; 3. Delivery not similar intensity as comparator; 4. Not the intervention of interest.
c Comparator key: 1. Not clearly defined; 2. Not standard or optimal; 3. Delivery not similar intensity as intervention; 4. Not delivered effectively.
d Outcomes key: 1. Key health outcomes not addressed; 2. Physiologic measures, not validated surrogates; 3. No CONSORT reporting of harms; 4. Not establish and validated measurements; 5. Clinical significant difference not prespecified; 6. Clinical significant difference not supported.
e Follow-Up key: 1. Not sufficient duration for benefit; 2. Not sufficient duration for harms.

Table 11. Study Design and Conduct Gaps

Study; Trial

Allocationa

Blindingb

Selective Reportingc

Data Completenessd

Powere

Statisticalf

Davis et al (2013)44; NCT00534235

3. Allocation concealment unclear

4. No independent adjudication or preset criteria for subsequent intervention

3. Evidence of selective reporting

     

The evidence gaps stated in this table are those notable in the current review; this is not a comprehensive gaps assessment.
Allocation key: 1. Participants not randomly allocated; 2. Allocation not concealed; 3. Allocation concealment unclear; 4. Inadequate control for selection bias.
Blinding key: 1. Not blinded to treatment assignment; 2. Not blinded outcome assessment; 3. Outcome assessed by treating physician; 4. No independent adjudication or preset criteria for subsequent intervention.
c Selective Reporting key: 1. Not registered; 2. Evidence of selective reporting; 3. Evidence of selective publication.
d Data Completeness key: 1. High loss to follow-up or missing data; 2. Inadequate handling of missing data; 3. High number of crossovers; 4. Inadequate handling of crossovers; 5. Inappropriate exclusions; 6. Not intent to treat analysis (per protocol for noninferiority trials).
e Power key: 1. Power calculations not reported; 2. Power not calculated for primary outcome; 3. Power not based on clinically important difference.
f Statistical key: 1. Analysis is not appropriate for outcome type: (a) continuous; (b) binary; (c) time to event; 2. Analysis is not appropriate for multiple observations per patient; 3. Confidence intervals and/or p values not reported; 4. Comparative treatment effects not calculated.

Subsection Summary: coflex Device Plus Decompression vs Decompression Plus Posterolateral Fusion
FDA's approval of coflex was based on an open-labeled, randomized, noninferiority trial that compared the noninferiority of coflex plus decompression with decompression plus fusion in patients who had spinal stenosis, significant back pain, and up to grade 1 spondylolisthesis. Use of the noninferiority framework by FDA assumed that decompression plus fusion was the standard of care for patients with spinal stenosis with up to grade 1 spondylolisthesis and, because fusion is a more invasive procedure that requires longer operative time and has a potential for higher surgical and postsurgical complications, demonstrating noninferiority with a less invasive procedure such as coflex would be adequate to demonstrate a net benefit in health outcomes. However, subsequent to the approval of coflex, 2 RCTs (SSSS, SLIP) assessing the superiority of adding fusion to decompression over decompression alone reported a lack of or marginal benefit. The SSSS trial, which was adequately powered to detect a 12-point difference in ODI score, showed no difference in ODI scores between the 2 treatment arms. Hence, the results generated from a noninferiority trial using a comparator whose net benefit on health outcomes is uncertain confound meaningful interpretation of its results.

coflex Device Plus Decompression vs Decompression Alone
Schmidt et al (2018) reported on results of an RCT in patients with moderate-to-severe LSS and back pain with or without spondylolisthesis randomized to open microsurgical decompression with interlaminar stabilization using the coflex device (n=110) or open microsurgical decompression alone (n=115).45 Trial characteristics and results at 24 months are summarized in Tables 12 and 13. The proportion of patients who met the criteria for composite clinical success at 24 months was statistically and significantly higher in the coflex arm (58.4%) than in the decompression alone arm (41.7%; p=0.017), with a treatment difference of 16.7% (95% confidence interval, 3.1% to 30.2%). This result was driven primarily by the lower proportion of patients who received an epidural steroid injection in the coflex arm (4.5%) vs the decompression alone arm (14.8%; p=0.010) at 24 months.

The proportion of patients with ODI success among those censored for subsequent secondary interventions was not statistically significant between the treatment (75.6%) and the control arms (70.4%; p=0.47). The difference in the proportion of patients overall who had ODI success in the overall sample was also not statistically significant (55% vs 44%, p=0.091).

None of the other outcomes (data not shown) showed statistically significant differences between the treatment and control arms; outcomes included success measured on the ZCQ (success was defined as an improvement in 2 or 3 ZCQ criteria), success measured on a VAS for pain (success defined as a >20-mm change from baseline), reduction in VAS leg pain, success on a walking distance test (either ≥8-minute walk improvement or the ability to walk to the maximum 15-minute limit), the proportion of patients receiving secondary surgical interventions, or 1- and 2-year survival (Kaplan-Meier) estimates without secondary surgical interventions or survival curves for time to first secondary intervention.

Table 12. Summary of Key RCT Characteristics

Study; Trial

Countries

Sites

Dates

Participants

Interventions

         

Active

Comparator

Schmidt et al (2018)45; NCT01316211

Germany

7

  2008-2014

Patients with moderate-to-severe LSS with or without spondylolisthesis and significant back pain (N=255)

Decompression with interlaminar stabilization (n=129)

Open microsurgical decompression alone (n=131)

LSS: lumbar spinal stenosis; RCT: randomized controlled trial.

Table 13. Summary of Key RCT Outcomes

Study

CCSa

15-Point Improvement in ODI Score (all patients)

15-Point Improvement in ODI Score (those not receiving a secondary intervention)

No Secondary Surgical Intervention or Lumbar Injection

No Secondary Surgical Intervention

No Secondary Lumbar Injection

Schmidt et al (2018)45

         

N

204

255

132

225

225

225

D plus ILS

59 (58)

69 (55)

62 (76)

91 (83)

96 (87)

105 (96)

D alone

43 (42)

57 (44)

50 (70)

84 (73)

98 (85)

98 (85)

%Δ (95% CI)

16.7
(3.1 to 30.2)

10.6
(-1.6 to 22.8)

5.2
(-8.9 to 19.3)

9.7
(-1.1 to 20.4)

2.1
(-6.9 to 11.0)

10.2
(2.7 to 17.8)

p

0.017

0.091

0.470

0.081

0.655

0.010

Values are n, n (%), or %.
CCS: composite clinical success; CI: confidence interval; D: decompression; ILS: interlaminar stabilization; ODI: Oswestry Disability Index; RCT randomized controlled trial.
CCS defined as meeting all 4 criteria: (1) ODI success with improvement >15 points; (2) survivorship with no secondary surgical intervention or lumbar injection; (3) neurologic maintenance or improvement without worsening; and (4) no device- or procedure-related severe adverse events.

The purpose of the gaps tables (see Tables 14 and 15) is to display notable gaps identified in each study. Major limitations are discussed below.

  • Based on the reporting by Schmidt et al (2018), 254 patients were randomized but data for only 204 patients were analyzed for the primary outcome measure.45 Thus, data of 20% of patients were excluded. While the proportion of patients excluded was comparable in both arms, the investigators did not explain the missing data of these 50 patients. Lack of a consistent approach in reporting and handling of missing data (patients who remained in the trial but for whom data for repeated longitudinal measures were missing), including describing methods to minimize missing data, reporting reasons for missing data, and using appropriate multiple imputation statistical techniques and sensitivity analysis46  to handle missing data, makes interpretation of trial results challenging.
  • The observed treatment effect on the primary composite outcome was primarily driven by a reduction in the use of rescue epidural steroid injection. One concern is bias that could have been introduced by the open-label design where the treating surgeon also made the assessment that additional intervention with lumbar steroid was needed. The trial design did not include features commonly used to address this problem, such as preset criteria for subsequent intervention, or independent blinded adjudication to verify that subsequent intervention was merited.
  • The inclusion of epidural and facet joint injections in the end point may be inappropriate for this trial. Epidural injections are less invasive than reoperations, revisions, removal, and supplemental fixations. Nonsurgical therapy, including epidural or facet injections, would be an expected adjunct to decompression alone in patients with predominant back pain. In this context, epidural injections may be offered to provide temporary pain relief that allows a patient to progress with a rehabilitative stretching and exercise program. Censoring patients who undergo particular components of nonsurgical back care may be inappropriate in this context. A better approach would be to measure and report ODI for all patients, or ODI success in all patients except for those who have revisions or reoperations, at 24 months.
  • Because of concerns about potential bias, inconsistent reporting of analysis as intention-to-treat, and a lack of critical discussion of the number, timing, pattern, and reason for and possible implications of missing values, the magnitude of difference might have been overestimated.

Table 14. Relevance Gaps

Study

Populationa

Interventionb

Comparatorc

Outcomesd

Follow-Upe

Schmidt et al(2018)45

   

1. In the control arm, nonsurgical treatment for back pain after decompression should be described

3. No CONSORT reporting of harms

 

1, 2. Present study reports only on the first 2 y of the 5-y follow-up required by FDA

The evidence gaps stated in this table are those notable in the current review; this is not a comprehensive gaps assessment.
FDA: Food and Drug Administration.
Population key: 1. Intended use population unclear; 2. Clinical context is unclear; 3. Study population is unclear; 4. Study population not representative of intended use
Intervention key: 1. Not clearly defined; 2. Version used unclear; 3. Delivery not similar intensity as comparator; 4. Not the intervention of interest.
c Comparator key: 1. Not clearly defined; 2. Not standard or optimal; 3. Delivery not similar intensity as intervention; 4. Not delivered effectively.
d Outcomes key: 1. Key health outcomes not addressed; 2. Physiologic measures, not validated surrogates; 3. No CONSORT reporting of harms; 4. Not establish and validated measurements; 5. Clinical significant difference not prespecified; 6. Clinical significant difference not supported.
e Follow-Up key: 1. Not sufficient duration for benefit; 2. Not sufficient duration for harms.

Table 15. Study Design and Conduct Gaps

Study

Allocationa

Blindingb

Selective Reportingc

Data Completenessd

Powere

Statisticalf

Schmidt et al (2018)45

 

1. Not blinded to treatment assignment

4. No independent adjudication or preset criteria for subsequent intervention

 

1. High loss to follow-up or missing data

2. Inadequate handling of missing data. LOCF may not be the most appropriate approach

6. Not intention-to-treat analysis

2. Power not calculated for primary outcome

 

 

 

The evidence gaps stated in this table are those notable in the current review; this is not a comprehensive gaps assessment.
LOCF: last observation carried forward.
Allocation key: 1. Participants not randomly allocated; 2. Allocation not concealed; 3. Allocation concealment unclear; 4. Inadequate control for selection bias.
Blinding key: 1. Not blinded to treatment assignment; 2. Not blinded outcome assessment; 3. Outcome assessed by treating physician; 4 No independent adjudication or preset criteria for subsequent intervention.
c Selective Reporting key: 1. Not registered; 2. Evidence of selective reporting; 3. Evidence of selective publication.
d Data Completeness key: 1. High loss to follow-up or missing data; 2. Inadequate handling of missing data; 3. High number of crossovers; 4. Inadequate handling of crossovers; 5. Inappropriate exclusions; 6. Not intent to treat analysis (per protocol for noninferiority trials).
e Power key: 1. Power calculations not reported; 2. Power not calculated for primary outcome; 3. Power not based on clinically important difference.
f Statistical key: 1. Analysis is not appropriate for outcome type: (a) continuous; (b) binary; (c) time to event; 2. Analysis is not appropriate for multiple observations per patient; 3. Confidence intervals and/or p values not reported; 4. Comparative treatment effects not calculated.

Nonrandomized Studies
Röder et al (2015) reported on a small cross-registry study that compared lumbar decompression plus coflex (SWISSspine Registry) with lumbar decompression alone (Spine Tango Registry) in 50 pairs matched by a multifactorial propensity score.47 SWISSspine is a governmentally mandated registry from Switzerland for coverage with evidence development. Spine Tango is a voluntary registry from the Spine Society of Europe. Both registries use the numeric rating scale (NRS) for back and leg pain, as well as the Core Outcome Measures Index as the patient-based outcome instrument. The Core Outcome Measures Index consists of 7 questions to evaluate pain, function, well-being, quality of life, and disability. At 7- to 9-month follow-up, the coflex group had greater reductions in NRS back pain score (3.8 vs 2.5, p=0.014), NRS leg pain score (4.3 vs 2.5, p<0.001), NRS maximum pain score (4.1 vs 2.3, p=0.002), and greater improvement in Core Outcome Measures Index score (3.7 vs 2.5; p=0.029). Back pain improved by the minimum clinically relevant change in about 60% of patients in the decompression alone group vs 78% in the coflex plus decompression group.

Because of substantial baseline differences between the compared groups, small sample size, and short follow-up time, there is a high risk that the Röder study's estimate of the effect of decompression alone versus decompression plus coflex is biased. Decompression alone had better outcomes than those reported by Röder et al (2015) in a larger, well-conducted, 12-month European registry study of patients with spinal stenosis, significant back, and no spondylolisthesis.48

Richter et al (2010) reported on a prospective case-control study of the coflex device in 60 patients who underwent decompression surgery.49 Richter et al (2014) also published a 2-year follow-up.50 The surgeon determined whether the midline structures were preserved or resected and whether the coflex device was implanted (1 or 2 levels). The indications for the 2 groups were identical and use of the device was considered incidental to the surgery. At 1- and 2-year follow-ups, placement of a coflex device did not significantly improve the clinical outcome compared with decompression surgery alone.

Some radiologic findings with the coflex device require additional study to determine their clinical significance. Tian et al (2013) reported a high rate (81.2%) of heterotopic ossification at follow-up (range, 24-57 months) in patients who had received a coflex device.51 In 16 (50%) of 32 patients, heterotopicossification was detected in the interspinous space but had not bridged the space, while in 2 (6.3%) patients there was interspinous fusion. In the 9 patients followed for more than 3 years, class II (interspinous space but not bridging) and class III (bridging) heterotopic ossification were detected in all nine. Lee et al (2016) reported erosion around the spinous process and reductions in disc height and range of motion in patients treated with a coflex device plus spinal decompression and had at least 24 months of follow-up.52 Erosion around the coflex device, which was observed in 47% of patients, has the potential to result in spinous process fracture or device malposition. Continued follow-up is needed.

Subsection Summary: coflex Device Plus Decompression vs Decompression Alone
The pivotal RCT, conducted in a patient population who had moderate-to-severe LSS with or without spondylolisthesis, showed that a greater proportion of patients who received coflex plus decompression achieved the primary end point of composite clinical success compared with decompression alone. This composite end point was primarily driven by a greater proportion of patients who received a secondary rescue epidural steroid injection in the control arm while there was no difference in the proportion of patients who achieved a meaningful reduction of 15 points in ODI score in the treatment and the control arms. However, the decision to use rescue epidural steroid injection introduced possible bias given that the trial was open-label. No attempts were made to mitigate this potential bias using protocol-mandated standard objective clinical criteria to guide decisions about the use of secondary interventions and subsequent adjudication of these events by an independent blinded committee. Given these critical shortcomings, trial results might have been biased. Greater certainty about the net health outcome of adding coflex to decompression surgery might be demonstrated when results of 5-year follow-up of these trials and an ongoing RCT (NCT02555280) on decompression with and without the coflex implant in the United States are published.

Clinical input supplements and informs the interpretation of the published evidence. Clinical input respondents were mixed in the level of support of this indication. While some of the expert opinion supported a potential benefit in carefully selected individuals, other experts were not confident of a clinically meaningful benefit or use in generally accepted medical practice, citing long-term complications leading to removal of the device. Some clinical input suggested that spacers may have utility in patients who are high risk for general anesthesia. Consideration of existing studies as indirect evidence regarding the outcomes of using spacers in this subgroup is limited by substantial uncertainty regarding the balance of potential benefits and harms. The main source of uncertainty about the benefits versus risks of using coflex plus laminectomy in patients who are not able to have general anesthesia is whether revisions, removals, and other secondary surgical procedures can be conducted safely if they are needed. Further details from clinical input included in the Clinical Input section later in the review and the Appendix.

Summary of Evidence
The following conclusions are based on a review of the evidence, including, but not limited to, published evidence and clinical expert opinion, via BCBSA's Clinical Input Process.

For individuals who have spinal stenosis and no spondylolisthesis or grade 1 spondylolisthesis who receive an interspinous or interlaminar spacer as a stand-alone procedure, the evidence includes 2 randomized controlled trials of 2 spacers (Superion Indirect Decompression System, coflex interlaminar implant). Relevant outcomes are symptoms, functional outcomes, quality of life, and treatment-related morbidity. Overall, the use of interspinous or interlaminar distraction devices (spacers) as an alternative to spinal decompression has shown a high failure and complication rates. A pivotal trial compared the Superion Interspinous Spacer with the X-STOP (which is no longer marketed), without conservative care or standard surgery comparators. The trial reported significantly better outcomes with the Superion Interspinous Spacer on some measures. For example, the trial reported more than 80% of patients experienced improvements in certain quality of life outcome domains. Interpretation of this trial is limited by questions about the number of patients used to calculate success rates, the lack of efficacy of the comparator, and the lack of an appropriate control group treated by surgical decompression. The coflex interlaminar implant (formerly called the interspinous U) was compared with decompression in the multicenter, double-blind Foraminal Enlargement Lumbar Interspinous distraXion trial. Functional outcomes and pain levels were similar in the 2 groups at 1-year follow-up, but reoperation rates due to the absence of recovery were substantially higher with the coflex implant (29%) than with bony decompression (8%). For patients with 2-level surgery, the reoperation rate was 38% for coflex and 6% for bony decompression. At 2 years, reoperations due to the absence of recovery had been performed in 33% of the coflex group and 8% of the bony decompression group. The evidence is insufficient to determine the effects of the technology on health outcomes.

For individuals who have spinal stenosis and no spondylolisthesis or grade 1 spondylolisthesis who receive an interlaminar spacer with spinal decompression surgery, the evidence includes randomized controlled trials and nonrandomized comparative studies. Relevant outcomes are symptoms, functional outcomes, quality of life, and treatment-related morbidity. Use of the coflex interlaminar implant as a stabilizer after surgical decompression has been studied in 2 situations--as an adjunct to decompression compared with decompression alone (superiority) and as an alternative to spinal fusion after decompression (noninferiority). In a randomized controlled trial conducted in a patient population with moderate-to-severe lumbar spinal stenosis with significant back pain and up to grade 1 spondylolisthesis, there was no difference in the primary outcome measure, the Oswestry Disability Index (ODI), between the patients treated with coflex plus decompression vs. decompression alone. "Composite clinical success" (CCS), defined as a minimum 15-point improvement in ODI score, no reoperations, no device-related complications, no epidural steroid injections in the lumbar spine, and no persistent new or worsening sensory or motor deficit, was used to assess superiority. A greater proportion of patients who received coflex plus decompression instead of decompression alone achieved the composite endpoint. However, the superiority of coflex plus decompression is uncertain because the difference in the CCS was primarily driven by a greater proportion of patients in the control arm who received a secondary rescue epidural steroid injection. Because the trial was open-label, surgeons' decision to use epidural steroid injection could have been affected by their knowledge of the patient's treatment. Consequently, including this component in the composite clinical success measure might have overestimated the potential benefit of treatment. This bias could have been mitigated using protocol-mandated standard objective clinical criteria to guide decisions about secondary interventions and subsequent adjudication of these events by an independent blinded committee. For decompression with coflex vs decompression with spinal fusion, the pivotal randomized controlled trial, conducted in a patient population with spondylolisthesis no greater than grade 1 and significant back pain, showed that stabilization of decompression with the coflex implant was noninferior to decompression with spinal fusion for the composite clinical success measure. However, there is uncertainty about the net benefit of routinely adding spinal fusion to decompression in patients with no or low-grade spondylolisthesis. Therefore, demonstrating the noninferiority of coflex plus spinal decompression vs spinal decompression plus fusion, a comparator whose benefit on health outcomes is uncertain, makes it difficult to apply the results of the study. 

Clinical Input From Physician Specialty Societies and Academic Medical Centers
While the various physician specialty societies and academic medical centers may collaborate with and make recommendations during this process, through the provision of appropriate reviewers, input received does not represent an endorsement or position statement by the physician specialty societies or academic medical centers, unless otherwise noted.

2018 Input
In response to requests, clinical input on the use of interlaminar spacer with spine decompression in individuals with spinal stenosis, predominant back pain, and no or grade 1 spondylolisthesis who failed conservative treatment was received from 6 respondents, including 2 specialty society-level responses and 4 physician-level responses, including 2 identified through a specialty society and 2 through an academic medical center, while this policy was under review in 2018. Evidence from clinical input is integrated within the Rationale section summaries and the Summary of Evidence.

2011 Input
In response to requests, input was received from 2 physician specialty societies and 2 academic medical centers while this policy was under review in 2011. Two of those providing input agreed this technology is investigational due to the limited high-quality data on long-term outcomes (including durability). Two reviewers did not consider this technology investigational, stating that it has a role in the treatment of selected patients with neurogenic intermittent claudication.

2009 Input
In response to requests, input was received from 1 physician specialty society and 3 academic medical centers while this policy was under review in 2009. Differing input was received; several reviewers indicated data were sufficient to demonstrate improved outcomes.

PRACTICE GUIDELINES AND POSITION STATEMENTS
International Society for the Advancement of Spine Surgery
The International Society for the Advancement of Spine Surgery (2016) published recommendations and coverage criteria for decompression with interlaminar stabilization.53 The Society concluded, based in part on a conference presentation of a level 1 study, that an interlaminar spacer in combination with decompression can provide stabilization in patients who do not present with greater than grade 1 instability. The document did not address interspinous and interlaminar distraction devices without decompression.

North American Spine Society
The North American Spine Society (NASS; 2018) published specific coverage policy recommendations on the lumbar interspinous device without fusion and with decompression.54 NASS recommended that:

"Stabilization with an interspinous device without fusion in conjunction with laminectomy may be indicated as an alternative to lumbar fusion for degenerative lumbar stenosis with or without low-grade spondylolisthesis (less than or equal to 3 mm of anterolisthesis on a lateral radiograph) with qualifying criteria when appropriate:

  1. Significant mechanical back pain is present (in addition to those symptoms associated with neural compression) that is felt unlikely to improve with decompression alone. Documentation should indicate that this type of back pain is present at rest and/or with movement while standing and does not have characteristics consistent with neurogenic claudication.
  2. A lumbar fusion is indicated post-decompression for a diagnosis of lumbar stenosis with a Grade 1 degenerative spondylolisthesis as recommended in the NASS Coverage Recommendations for Lumbar Fusion.
  3. A lumbar laminectomy is indicated as recommended in the NASS Coverage Recommendations for Lumbar Laminectomy.
  4. Previous lumbar fusion has not been performed at an adjacent segment.
  5. 5. Previous decompression has been performed at the intended operative segment.

Interspinous devices are NOT indicated in cases that do not fall within the above parameters. In particular, they are not indicated in the following scenarios and conditions:

  1. Degenerative spondylolisthesis of Grade 2 or higher.
  2. Degenerative scoliosis or other signs of coronal instability.
  3. Dynamic instability as detected on flexion-extension views demonstrating at least 3 mm of change in translation.
  4. Iatrogenic instability or destabilization of the motion segment.
  5. A fusion is otherwise not indicated for a Grade 1 degenerative spondylolisthesis and stenosis as per the NASS Coverage Recommendations for Lumbar Fusion.
  6. A laminectomy for spinal stenosis is otherwise not indicated as per the NASS Coverage Recommendations for Lumbar Laminectomy."

American Pain Society
The guidelines from the American Pain Society (2009) indicated that interspinous spacer devices, based on fair evidence, have a B recommendation (clinicians should consider offering the intervention).55,56 The net benefit was considered moderate through 2 years, with insufficient evidence to estimate the net benefit for long-term outcomes.

National Institute for Health and Care Excellence
The National Institute for Health and Care Excellence (2010) published guidance that indicated "Current evidence on interspinous distraction procedures for lumbar spinal stenosis causing neurogenic claudication shows that these procedures are efficacious for carefully selected patients in the short and medium term, although failure may occur and further surgery may be needed."57 The evidence reviewed consisted mainly of reports on X-STOP.

U.S. Preventive Services Task Force Recommendations
Not applicable.

Ongoing and Unpublished Clinical Trials
Some currently unpublished trials that might influence this review are listed in Table 16.

Table 16. Summary of Key Trials 

NCT No.

Trial Name

Planned Enrollment

Completion Date

Ongoing

     

NCT02555280a

A 2 and 5 Year Comparative Evaluation of Clinical Outcomes in the Treatment of Degenerative Spinal Stenosis With Concomitant Low Back Pain by Decompression With and Without Additional Stabilization Using the Coflex®Interlaminar Technology for FDA Real Conditions of Use Study (Post-Approval ‘Real Conditions of Use' Study)

345

Jun 2022

NCT02457468a

The Coflex®COMMUNITY Study: An Observational Study of Coflex® Interlaminar Technology

500

Jun 2023

Unpublished      

NCT03041896a

Retrospective Evaluation of the Clinical and Radiographic Performance of Coflex® Interlaminar Technology Versus Decompression With or Without Fusion

5,000

Aug 2018 (completed)

NCT: national clinical trial.
a Denotes industry-sponsored or cosponsored trial. 

References:   

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  14. Deyo RA, Mirza SK, Martin BI, et al. Trends, major medical complications, and charges associated with surgery for lumbar spinal stenosis in older adults. Jama. Apr 7 2010;303(13):1259-1265. PMID 20371784.
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  16. Yoshihara H, Yoneoka D. National trends in the surgical treatment for lumbar degenerative disc disease: United States, 2000 to 2009. Spine J. Feb 1 2015;15(2):265-271. PMID 25281920.
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  18. Ghogawala Z, Dziura J, Butler WE, et al. Laminectomy plus fusion versus laminectomy alone for lumbar spondylolisthesis. N Engl J Med. Apr 14 2016;374(15):1424-1434. PMID 27074067.
  19. Peul WC, Moojen WA. Fusion surgery for lumbar spinal stenosis [letter]. N Engl J Med. Aug 11 2016;375(6):601. PMID 27517106.
  20. El Tecle NE, Dahdaleh NS. Fusion surgery for lumbar spinal stenosis [letter]. N Engl J Med. Aug 11 2016;375(6):597. PMID 27509110.
  21. Forsth P, Michaelsson K, Sanden B. Fusion surgery for lumbar spinal stenosis [letter]. N Engl J Med. Aug 11 2016;375(6):599-600. PMID 27509109.
  22. Su BW, Vaccaro AR. Fusion surgery for lumbar spinal stenosis [letter]. N Engl J Med. Aug 11 2016;375(6):597-598. PMID 27509111.
  23. Vasudeva VS, Chi JH. Fusion surgery for lumbar spinal stenosis [letter]. N Engl J Med. Aug 11 2016;375(6):598. PMID 27509112.
  24. Dijkerman ML, Overdevest GM, Moojen WA, et al. Decompression with or without concomitant fusion in lumbar stenosis due to degenerative spondylolisthesis: a systematic review. Eur Spine J. Jul 2018;27(7):1629-1643. PMID 29404693.
  25. Pearson AM. Fusion in degenerative spondylolisthesis: how to reconcile conflicting evidence. J Spine Surg. Jun 2016;2(2):143-145. PMID 27683712.
  26. Inose H, Kato T, Yuasa M, et al. Comparison of decompression, decompression plus fusion, and decompression plus stabilization for degenerative spondylolisthesis: a prospective, randomized study. Clin Spine Surg. Aug 2018;31(7):E347-E352. PMID 29877872.
  27. Food and Drug Administration. Premarket Approval Application: coflex® Interlaminar Technology (P110008). 2012; https://www.accessdata.fda.gov/cdrh_docs/pdf11/P110008a.pdf. Accessed May 18, 2018.
  28. Patel VV, Whang PG, Haley TR, et al. Superion Interspinous Process Spacer for intermittent neurogenic claudication secondary to moderate lumbar spinal stenosis: two-year results from a randomized controlled FDA-IDE pivotal trial. Spine (Phila Pa 1976). Dec 9 2015;40(5):275-282. PMID 25494323.
  29. Nunley, PP, Deer, TT, Benyamin, RR, Staats, PP, Block, JJ. Interspinous process decompression is associated with a reduction in opioid analgesia in patients with lumbar spinal stenosis. J Pain Res, 2018 Dec 13;11:2943-2948. PMID 30538533.
  30. Nunley, PP, Patel, VV, Orndorff, DD, Lavelle, WW, Block, JJ, Geisler, FF. Interspinous Process Decompression Improves Quality of Life in Patients with Lumbar Spinal Stenosis. Minim Invasive Surg, 2018 Jul 31;2018:1035954. PMID 30057811.
  31. Patel VV, Nunley PD, Whang PG, et al. Superion((R)) InterSpinous Spacer for treatment of moderate degenerative lumbar spinal stenosis: durable three-year results of a randomized controlled trial. J Pain Res. Oct 2015;8:657-662. PMID 26491369.
  32. Nunley PD, Patel VV, Orndorff DG, et al. Superion interspinous spacer treatment of moderate spinal stenosis: 4-year results. World Neurosurg. Aug 2017;104:279-283. PMID 28479526.
  33. Nunley PD, Patel VV, Orndorff DG, et al. Five-year durability of stand-alone interspinous process decompression for lumbar spinal stenosis. Clin Interv Aging. Sep 6 2017;12:1409-1417. PMID 28919727.
  34. Moojen WA, Arts MP, Jacobs WC, et al. Interspinous process device versus standard conventional surgical decompression for lumbar spinal stenosis: randomized controlled trial. BMJ. Nov 14 2013;347:f6415. PMID 24231273.
  35. Moojen W, Arts M, Jacobs W, et al. The Felix Trial: clinical results after one year and subgroup analysis: Introducing new implants and imaging techniques for lumbar spinal stenosis [doctoral dissertation], Universiteit Leiden; 2014;69-90.
  36. Moojen WA, Arts MP, Jacobs WC, et al. IPD without bony decompression versus conventional surgical decompression for lumbar spinal stenosis: 2-year results of a double-blind randomized controlled trial. Eur Spine J. Oct 2015;24(10):2295-2305. PMID 25586759.
  37. Bae HW, Lauryssen C, Maislin G, et al. Therapeutic sustainability and durability of coflex interlaminar stabilization after decompression for lumbar spinal stenosis: a four year assessment. Int J Spine Surg. Jun 10 2015;9:15. PMID 26056630.
  38. Musacchio MJ, Lauryssen C, Davis RJ, et al. Evaluation of decompression and interlaminar stabilization compared with decompression and fusion for the treatment of lumbar spinal stenosis: 5-year follow-up of a prospective, randomized, controlled trial. Int J Spine Surg. 2016;10:6. PMID 26913226.
  39. Bae HW, Davis RJ, Lauryssen C, et al. Three-year follow-up of the prospective, randomized, controlled trial of coflex interlaminar stabilization vs instrumented fusion in patients with lumbar stenosis. Neurosurgery. Aug 2016;79(2):169-181. PMID 27050538.
  40. Simon RB, Dowe C, Grinberg S, et al. The 2-Level Experience of Interlaminar Stabilization: 5-Year Follow-Up of a Prospective, Randomized Clinical Experience Compared to Fusion for the Sustainable Management of Spinal Stenosis. International Journal of Spine Surgery. 2018;12(4):419. PMID.
  41. Abjornson C, Yoon B-JV, Callanan T, et al. Spinal stenosis in the absence of spondylolisthesis: can interlaminar stabilization at single and multi-levels provide sustainable relief? Int J Spine Surg. Mar 30 2018;12(1):64-69. PMID.
  42. Davis R, Auerbach JD, Bae H, et al. Can low-grade spondylolisthesis be effectively treated by either coflex interlaminar stabilization or laminectomy and posterior spinal fusion? Two-year clinical and radiographic results from the randomized, prospective, multicenter US investigational device exemption trial: clinical article. J Neurosurg Spine. Aug 2013;19(2):174-184. PMID 23725394.
  43. Abjornson, CC, Yoon, BB, Callanan, TT, Shein, DD, Grinberg, SS, Cammisa, FF. Spinal Stenosis in the Absence of Spondylolisthesis: Can Interlaminar Stabilization at Single and Multi-levels Provide Sustainable Relief?. Int J Spine Surg, 2018 Oct 4;12(1). PMID 30280085.
  44. Davis RJ, Errico TJ, Bae H, et al. Decompression and Coflex interlaminar stabilization compared with decompression and instrumented spinal fusion for spinal stenosis and low-grade degenerative spondylolisthesis: two-year results from the prospective, randomized, multicenter, Food and Drug Administration Investigational Device Exemption trial. Spine (Phila Pa 1976). Aug 15 2013;38(18):1529-1539. PMID 23680830.
  45. Schmidt S, Franke J, Rauschmann M, et al. Prospective, randomized, multicenter study with 2-year follow-up to compare the performance of decompression with and without interlaminar stabilization. J Neurosurg Spine. Jan 26 2018:1-10. PMID 29372860.
  46. Lachin JM. Fallacies of last observation carried forward analyses. Clin Trials. Apr 2016;13(2):161-168. PMID 26400875.
  47. Röder C, Baumgartner B, Berlemann U, et al. Superior outcomes of decompression with an interlaminar dynamic device versus decompression alone in patients with lumbar spinal stenosis and back pain: a cross registry study. Eur Spine J. Oct 2015;24(10):2228-2235. PMID 26187621.
  48. Crawford CH, 3rd, Glassman SD, Mummaneni PV, et al. Back pain improvement after decompression without fusion or stabilization in patients with lumbar spinal stenosis and clinically significant preoperative back pain. J Neurosurg Spine. Nov 2016;25(5):596-601. PMID 27285666.
  49. Richter A, Schutz C, Hauck M, et al. Does an interspinous device (Coflex) improve the outcome of decompressive surgery in lumbar spinal stenosis? One-year follow up of a prospective case control study of 60 patients. Eur Spine J. Feb 2010;19(2):283-289. PMID 19967546.
  50. Richter A, Halm HF, Hauck M, et al. Two-year follow-up after decompressive surgery with and without implantation of an interspinous device for lumbar spinal stenosis: a prospective controlled study. J Spinal Disord Tech. Aug 2014;27(6):336-341. PMID 22643187.
  51. Tian NF, Wu AM, Wu LJ, et al. Incidence of heterotopic ossification after implantation of interspinous process devices. Neurosurg Focus. Aug 2013;35(2):E3. PMID 23905954.
  52. Lee N, Shin DA, Kim KN, et al. Paradoxical radiographic changes of Coflex Interspinous device with minimum 2-year follow-up in lumbar spinal stenosis. World Neurosurg. Jan 2016;85:177-184. PMID 26361324.
  53. Guyer RD, Musacchio MJ, Cammisa FP, et al. ISASS recommendations/coverage criteria for decompression with interlaminar stabilization - coverage indications, limitations, and/or medical necessity. Int J Spine Surg. 2016;10:Article 41. PMID.
  54. North American Spine Society. NASS Coverage Policy Recommendations: Lumbar interspinous device without fusion & with decompression. Burr Ridge, IL: NASS; 2018.
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  57. National Institute for Health and Care Excellence. Interspinous distraction procedures for lumbar spinal stenosis causing neurogenic claudication [IPG365]. 2010; https://www.nice.org.uk/guidance/IPG365. Accessed May 18, 2018.

Coding Section

Codes Number Description
CPT  22853 (effective 1/1/2017)

Insertion of interbody biomechanical device(s) (eg, synthetic cage, mesh) with integral anterior instrumentation for device anchoring (eg, screws, flanges), when performed, to intervertebral disc space in conjunction with interbody arthrodesis, each interspace (List separately in addition to code for primary procedure) 

  22854 (effective 1/1/2017)

Insertion of intervertebral biomechanical device(s) (eg, synthetic cage, mesh) with integral anterior instrumentation for device anchoring (eg, screws, flanges), when performed, to vertebral corpectomy(ies) (vertebral body resection, partial or complete) defect, in conjunction with interbody arthrodesis, each contiguous defect (List separately in addition to code for primary procedure) 

  22859 (effective 1/1/2017)

Insertion of intervertebral biomechanical device(s) (eg, synthetic cage, mesh, methylmethacrylate) to intervertebral disc space or vertebral body defect without interbody arthrodesis, each contiguous defect (List separately in addition to code for primary procedure) 

  22867 (effective 1/1/2017)

Insertion of interlaminar/interspinous process stabilization/distraction device, without fusion, including image guidance when performed, with open decompression, lumbar; single level 

  22868 (effective 1/1/2017)

Insertion of interlaminar/interspinous process stabilization/distraction device, without fusion, including image guidance when performed, with open decompression, lumbar; second level (List separately in addition to code for primary procedure)

  22869 (effective 1/1/2017)

Insertion of interlaminar/interspinous process stabilization/distraction device, without open decompression or fusion, including image guidance when performed, lumbar; single level 

  22870 (effective 1/1/2017)

Insertion of interlaminar/interspinous process stabilization/distraction device, without open decompression or fusion, including image guidance when performed, lumbar; second level (List separately in addition to code for primary procedure) 

  22899

Unlisted procedure, spine

ICD-9 Procedure 84.80

Insertion or replacement of interspinous process device(s)

ICD-9 Diagnosis  

Investigational for all codes

HCPCS C1821

Interspinous process distraction device (implantable)

ICD-10-CM (effective 10/01/15)  

Investigational for all codes

  M48.00-M48.08

Spinal stenosis code range

ICD-9-PCS (effective 10/01/15)  

ICD-10-PCS codes are only used for inpatient services.

 

0RH008Z, 0RH038Z, 0RH048Z, 0RH108Z, 0RH138Z, 0RH148Z, 0RH408Z, 0RH438Z, 0RH448Z, 0RH608Z, 0RH638Z, 0RH648Z, 0RHA08Z, 0RHA38Z, 0RHA48Z

Surgical, upper joints, insertion, spacer, interspinous process, code by body part and approach (open, percutaneous, percutaneous endoscopic)

 

0SH008Z, 0SH038Z, 0SH048Z, 0SH308Z, 0SH338Z, 0SH348Z

Surgical, lower joints, insertion, spacer, interspinous process, code by body part and approach (open, percutaneous, percutaneous endoscopic)

 

0RP008Z, 0RP038Z, 0RP048Z, 0RP108Z, 0RP138Z, 0RP148Z, 0RP408Z, 0RP438Z, 0RP448Z, 0RP608Z, 0RP638Z, 0RP648Z, 0RPA08Z, 0RPA38Z, 0RPA48Z

Surgical, upper joints, removal, spacer, interspinous process, code by body part and approach (open, percutaneous, percutaneous endoscopic)

 

0SP008Z, 0SP038Z, 0SP048Z, 0SP308Z, 0SP338Z, 0SP348Z

Surgical, lower joints, removal, spacer, interspinous process, code by body part and approach (open, percutaneous, percutaneous endoscopic)

Type of Service    
Place of Service    

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.  

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross and Blue Shield Association technology assessment program (TEC) and other non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies and accredited national guidelines.

"Current Procedural Terminology© American Medical Association.  All Rights Reserved" 

History From 2014 Forward     

06/01/2019 

Annual review, no change to policy intent. Updating description, regulatory status, rationale and references. 

10/19/2018 

Interim review to specify that Coflex can be considered medically necessary, but, ALL other distraction devices are investigational. No other changes. 

08/06/2018 

Interim review, expanding coverage to include medical necessity criteria for previously investigational devices. Policy reformatted to reflect this update. 

06/28/2018 

Annual review, no change to policy intent. Updating rationale and references.  

06/15/2017 

Annual review. Updating background, description, regulatory status, policy statement, policy guidelines, rationale and references. 

11/21/2016 

Updated coding in the coding section. No other changes. 

06/13/2016 

Annual review, no change to policy intent. Updating background, description, regulatory status, rationale and references. 

06/15/2015 

Annual review, added language to allow PEEK cages as medically necessary. Updated regulatory status, rationale and references. Added guidelines and coding. 

06/16/2014

Annual review. Added related policies. No change to policy intent.


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