ISASS Recommendations/Coverage Criteria for Decompression with Interlaminar Stabilization - Coverage Indications, Limitations, and/or Medical Necessity
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* Richard Guyer
* Michael Musacchio
* Frank P. Cammisa, Jr.
* Morgan P. Lorio

*   decompression
*   interlaminar stabilization (ils)
*   lumbar spinal stenosis (lss)

## Introduction

Broadly defined, lumbar spinal stenosis (LSS) is the progressive narrowing of the spinal canal and neural foramen resulting in pressure upon the nerve(s) leading to pain and/or numbness in the extremities, muscle weakness, bowel and bladder issues, and/or other pain related issues. However, the difficulty arises in that spinal stenosis is a heterogeneous condition with multiple etiologies which may present with disc height loss, facet hypertrophy, spondylolisthesis, retrolisthesis, coronal and/or sagittal plane deformity, and presence of osteophytes and facet cysts. Therefore, there is not a single surgical intervention that addresses all pathological variations of spinal stenosis, rather, there are several methods used to treat LSS. Diagnostic evaluation is needed to determine the correct surgical treatment solution to address anatomical and pathological variation as some patients can be treated by simple decompression while others may require a form of stabilization. This policy statement focuses on one treatment option: decompression with interlaminar stabilization. ISASS does not recommend any particular treatment method; the choice of treatment depends on the patient’s pathology and the expertise of the treating surgeon. ISASS recommends shared decisionmaking between the patient and the surgeon.

Due to a growing elderly population, there is a rising incidence of LSS and varying options of therapeutic pathways. The majority of patients diagnosed with LSS are initially managed conservatively with epidural steroid injections, physical therapy, and modification of activities of daily life. However, several studies have demonstrated that if there is no significant improvement in symptoms after 12 weeks of conservative treatment, generally, symptoms do not improve with time.1, 2 Patients with a diagnosis of LSS who do not experience leg and/or back pain symptom relief from conservative care management and who experience continued worsening of symptoms may be appropriate candidates for surgical treatment. Surgical treatment options include indirect decompression with interspinous distraction devices, direct surgical decompression, direct surgical decompression with interlaminar stabilization, and direct surgical decompression with fusion.

For mild spinal stenosis (or early-stage disease), an interspinous distraction device without an associated concomitant bony decompression may be considered as an alternative option to a decompression-alone procedure. The X-STOP (Medtronic, Memphis, TN) was approved by the FDA in 2006,3 however Medtronic removed the technology from the market in 2015. At present, the only non-fusion interspinous distraction device available in the United States is the Superion (VertiFlex, San Clemente, CA). Superion has been CE marked since 2007 and following a clinical study of 470 patients, the FDA approved the device for use on May 20, 2015.4 The data was sufficient for approval of a Category I CPT code effective January 1, 2017. This ISASS policy does not formally address coverage rationale for interspinous distraction devices without decompression pending further data and review of this type of procedural approach in treating LSS.

For patients with mild to moderate stenosis and no instability (absence of spondylolisthesis or presence of a stable spondylolisthesis) direct open or microsurgical decompression of the offending bony and soft tissue pathology is a widely-accepted and commonly performed surgical treatment solution.5 Direct surgical decompression may occasionally lead to instability (caused by continued degenerative processes, excessive facet resection, excess stress on remaining supporting structures, or natural history of LSS disease) which may result in recurrence of stenosis and leg and back pain. In order to achieve satisfactory results, adequate neural decompression and surgical excision of bone and soft tissue causing the stenosis should be the primary goal of surgery.5 There have been several studies comparing medical/interventional management to surgical decompression that have consistently shown that surgical decompression patients report both significantly better short-term and long-term improvement compared to medical management. In SPORT, Weinstein et al.6, 7 performed concurrent lumbar spinal stenosis prospective studies with a randomized and an observational cohort to study decompression compared to conservative care. At four years follow-up, 60% of decompression alone patients maintained a 15-point improvement in the Oswestry Disability Index (ODI) with a 28% treatment effect over medical management, which was statistically significant. In the decompression group, the re-operation rate ranged from 8% at two years to 13% at four years where 6% was due to recurrent stenosis. However, Modhia5 reviewed the Medicare database over a four-year period and showed readmission rates of 8 to 10% per year after failed microsurgical decompression for treatment of lumbar spinal stenosis resulting in injections for pain management, revision decompression, or conversion to fusion. Forsth et al.8 recently published a prospective, randomized study examining LSS patients with and without degenerative spondylolisthesis. Patients were divided into two treatment groups: decompression alone or decompression plus fusion. The results show no clinical differences between the groups at five years follow-up, but 21% of patients in the decompression alone group required revision surgery by a mean of 6.5 years follow up. Further, Ghogawala et al. prospectively studied patients with LSS and a stable spondylolisthesis and found a cumulative reoperation rate of 34% in the decompression alone group.9

Pedicle screw fusion is the standard of care treatment for patients with spinal stenosis with significant instability (unstable spondylolisthesis) and concomitant debilitating back pain often associated with sagittal and coronal plane deformity. The addition of instrumentation and fusion to provide a clinically meaningful difference compared to decompression alone in prospective, randomized studies with spondylolisthesis has been established when non-spondylolisthesis patients are within the cohort. Recent findings comparing decompression alone to decompression plus fusion are inconsistent relative to clinical outcomes providing greater improvement over decompression alone.8, 9 Forsth et al. showed significant differences in peri-operative outcomes favoring decompression alone, but no difference in clinical outcomes out to five years follow-up between decompression alone and decompression plus fusion in patients in a mixed patient cohort with and without spondylolisthesis.8 However, Ghogawala et al. found in patients with Grade 1 spondylolisthesis a greater improvement in SF-36 physical component and ODI at 4 years follow-up that was statistically significant over decompression alone.9 Both studies however still showed clinically significant reoperation rates in the fusion group, 22% and 14% respectively, but with even higher reoperation rates in the decompression alone cohort.8, 9

There exists a population of patients who present with moderate to severe stenosis, with concomitant back pain, where decompression alone does not adequately address back pain. Weinstein6and Kleinstück10 suggest that those patients with predominant back pain or facetogenic issues may benefit from stabilization. Interlaminar stabilization after direct decompression is a non-fusion surgical option that can provide the additional stability over decompression alone without the rigidity of an instrumented fusion. Currently, there is one product that has achieved FDA PMA approval for up to a Grade I spondylolisthesis, the coflex (Paradigm Spine, New York, NY). The findings from Kumar11comparing decompression alone and decompression with interlaminar stabilization, combined with the publication from Musacchio12comparing five-year outcomes of decompression with interlaminar stabilization and decompression plus fusion, provide compelling evidence supporting this as a treatment alternative for select patients with stenosis. Studies have shown that a non-fusion interlaminar stabilization device maintains motion, reduces both leg and back pain, and preserves foraminal height.12 Further, the studies have also shown clinical benefit for patients with and without spondylolisthesis.

## Coverage Rationale for Decompression with Interlaminar Stabilization

For the majority of spinal procedures, the addition of hardware instrumentation has offered the ability to improve effectiveness and sustainability by providing immediate stability. In some cases, a decompression procedure in of itself may create iatrogenic instability, compromising the structural integrity of the posterior elements. Important consideration should be given to the amount and degree of relative facet-driven back pain, presence and grade of spondylolisthesis/retrolisthesis, osteophytes and relative loss of disc height. In stenosis patients where a direct surgical decompression has been deemed medically necessary by the surgeon, and the patient does not present with gross instability (>Grade 1), non-fusion interlaminar stabilization can provide controlled reliable motion. The positioning between the lamina allows the physiological load to be offset from the facet joints, provides direct neurological decompression, and reestablishes the foraminal height.

Two prospective, randomized, multi-center, controlled, Level 1 clinical studies have been conducted to understand the sustainability and durability of decompression (D) with interlaminar stabilization (ILS). Raushmann et al.13 have recently completed a prospective, randomized, multi-center Level 1 clinical trial comparing decompression alone (DA) to D+ILS at 24-months in a 1:1 randomization of 230 patients. Patients must have failed 3 months of conservative treatment, be greater than 40 years old, report Visual Analog Scale (VAS) back pain ≥ 50, and have radiographically confirmed degenerative spinal stenosis. The primary clinical outcome success (no reoperations, revisions, or injections) was achieved in 82.7% (91/110) of the D+ILS patients compared to 73% (84/115) of the DA patients, trending towards statistical significance (p=0.081). Within the primary outcome, there was a statistically significant difference between the treatments with regard to no lumbar injections where 95.5% (105/110) of the D+ILS patients compared to 87% (100/115) of the DA patients achieved success (p = 0.025). The clinical composite success (CCS) was defined as the primary outcome success and an ODI improvement of at least 15 points. The CCS was achieved in 61.4% in the D+ILS group compared to 49% in the DA group, trending towards statistical significance (p = 0.076). Of the CCS patients, the additional component of no narcotics usage showed a statistically significant difference (p = 0.021) between D+ILS (58.4%) compared to DA (42.2%), and with the further addition of neurological success (no new or increasing neurological deficit), the statistically significant difference becomes more significant with 55.4% of D+ILS compared to 36.3% DA (p = 0.006). Finally, as spinal stenosis is most often related to leg pain, the CCS combined with VAS leg pain success showed a statistically significant difference with 69.3% of the D+ILS group compared to 59.2% of the DA group (p = 0.017). This study provides strong evidence showing the addition of interlaminar stabilization to a decompression procedure has significant advantages in quality of life and durability components for select patients within the LSS continuum.

The United States IDE trial compared decompression plus fusion (DF) to D+ILS for the treatment of moderate to severe lumbar spinal stenosis (47% with a spondylolisthesis and 53% without the presence of a spondylolisthesis), where 322 patients (215 D+ILS /107 DF, respectively) were followed through five years.12 Clinical outcomes measurements were gathered annually: ODI, leg and back pain VAS, and Zurich Claudication Questionnaire (ZCQ). At the five year follow-up, Musacchio et al.12 reported over 99% of D+ILS patients achieved pain improvement of at least 20 mm in VAS leg pain and over 80% achieved at least 15-point improvement in ODI. By all patient-derived parameters, the treatments were found equivalent, however a higher percentage of D+ILS patients at all follow-up time points achieved at least 15-point improvement in ODI, and at least 20 mm VAS leg pain and VAS back pain improvement compared to the DF group. The percentage of patients achieving a clinical improvement of at least 15-points in ODI at three months post operatively was 87% for D+ILS and 74% for DF. Leg pain was immediately and sustainably relieved in both patient groups evidenced by VAS Leg and ZCQ measurements. For the D+ILS group, VAS Leg scores were 76 preoperatively, and 23 at 60 months; for the DF group, VAS Leg scores were 78 preoperatively, and 25 at 60 months. ZCQ (Physical Function) scores in the D+ILS group were 2.8 preoperatively, and 1.7 at 60 months, while ZCQ scores for DF were 2.8 preoperatively, and 1.8 at 60 months. Furthermore, back pain was also immediately and sustainably relieved through facet off-loading in the D+ILS group, with VAS Back scores of 80 preoperatively, and 25 at 60 months. VAS Back scores for DF were 79 preoperatively, and 29 at 60 months.

In terms of reoperations/revisions, the results of Musacchio et al.12 show the majority of the D+ILS reoperations/revisions occurred within the first year post-operative associated with “learning curve” issues. The “learning curve” group accounted for 19 of the 35 revisions in the D+ILS group including wound-related issues, re-decompression, and/or poor patient selection/surgical planning. In comparison, 6 of the 19 revisions in the fusion group were early surgical issues. The DF group had a 6.5% rate of device-related failure requiring revision and 5.6% late-term (greater than one-year post-operative) ineffective treatment revisions, thereby an effective 12.1% overall revision rate. In comparison, the D+ILS group had a 2.8% rate of device-related revisions and 4.2% late-term ineffective treatment revisions resulting in an effective 7% overall revision rate at 5 years.

## Indications/Limitations of Coverage

Patients who have all of the following criteria may be eligible for decompression with interlaminar stabilization:

1.  Radiographic confirmation of at least moderate lumbar stenosis, which narrows the central spinal canal at 1 or 2 contiguous levels from L-1 to L-5 that require surgical decompression. Moderate stenosis is defined as > 25% reduction of the anteroposterior dimension compared with the next adjacent normal level, with nerve root crowding compared with the normal level, as determined by the surgeon on CT scanning or MRI.

2.  Radiographic confirmation of the absence of gross angular or translatory instability of the spine at index or adjacent levels (instability as defined by White and Panjabi: sagittal plane translation >4.0 mm or 15% or local sagittal plane rotation > 15° at L1–2, L2–3, and L3–4; >20° at L4–5 based on standing flexion-extension radiographs). Improved imaging technologies are able to better refine/detect previously undetected instability and as these technologies become more established, surgeons should expect to refine with specificity and clear delineation of appropriate surgical candidates requiring stabilization.

3.  Patients who experience relief in flexion from their symptoms of leg/buttocks/groin pain, with or without back pain, and who have undergone at least 12 weeks of non-operative treatment consisting of non-steroidal anti-inflammatory drugs and at least one of the following: rest, restriction of activities of daily living, physical therapy, or steroid injections.

Decompression with interlaminar stabilization is NOT indicated for patients with the following:

1.  More than 2 vertebral levels requiring surgical decompression.

2.  Prior surgical procedure that resulted in gross translatory instability of the lumbar spine.

3.  Prior fusion, implantation of a total disc replacement, or complete laminectomy at index level.

4.  Radiographically compromised vertebral bodies at any lumbar level(s) caused by current or past trauma, tumor, or infection.

5.  Severe facet hypertrophy requiring extensive bone removal that would cause gross instability.

6.  Radiographic confirmation of gross angular or translatory instability of the spine at index or adjacent levels with sagittal plane translation >4.0 mm as spondylolisthesis or retrolithesis

7.  Isthmic spondylolisthesis or spondylolysis (pars fracture).

8.  Degenerative lumbar scoliosis (Cobb angle > 25° lumbar segmental).

9.  Osteopenia and Osteoporosis.

10. Back or leg pain of unknown etiology.

11. Axial back pain only, with no leg, buttock, or groin pain.

12. Morbid obesity defined as a body mass index > 40.

13. Active or chronic infection—systemic or local.

14. Known history of Paget disease, osteomalacia, or any other metabolic bone disease (excluding osteopenia, which is addressed above).

15. Rheumatoid arthritis or other autoimmune disease requiring chronic steroid use.

16. Active malignancy: a patient with a history of any invasive malignancy (except nonmelanoma skin cancer), unless he/she has been treated with curative intent and there has been no clinical signs or symptoms of the malignancy for at least 5-years. Patients with a primary bony tumor are excluded as well.

17. Known allergy to titanium alloys or magnetic resonance contrast agents.

18. Cauda equina syndrome defined as neural compression causing neurogenic bowel or bladder dysfunction.

## Coding

### CPT Codes

Note: New codes are effective January 1, 2017.

*   CPT Code 22867: Insertion of interlaminar/interspinous process stabilization/distraction device, without fusion, including image guidance when performed, with open decompression, lumbar; single level.

*   CPT Code 22868: 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).

Prior to January 1, 2017, the following codes may be considered provisionally by the coder:

*   CPT Code 63030: Lumbar laminotomy (hemilaminectomy), 1 interspace.

*   CPT Code 63035: Lumbar laminotomy (hemilaminectomy), each additional interspace.

*   CPT Code 63047: Lumbar laminectomy, facetectomy and foraminotomy, single vertebral segment.

*   CPT Code 63048: Lumbar laminectomy, facetectomy and foraminotomy, each additional segment.

*   CPT Code 22899: Unlisted procedure, spine.

*   CPT Code 22840: Posterior non-segmental instrumentation.

*   CPT Code 0171T: Insertion of posterior spinous process distraction device, lumbar, single level.

*   CPT Code 0172T: Insertion of posterior spinous process distraction device, lumbar, each additional level.

## Documentation Requirements

*   A complete history and physical documenting spinal stenosis clinically, and radiologically, with progressive clinical symptoms even with documented conservative care.

*   Radiographic documentation of canal compromise, with MRI or CT evidence of moderate to severe spinal stenosis at one or two contiguous levels with up to Grade 1 spondylolisthesis.

*   A course of conservative treatments that include modification of activities, patient education, physical therapy, injection therapy including epidural steroid injections, and oral medication like steroids and nonsteroidal anti-inflammatory drugs (NSAIDs).

*   Symptomatology greater than 12-weeks with documented conservative care, progressive symptomatology, and failure to alleviate symptomatology short of surgical decompression.

## Surgeon Qualifications

Decompression with interlaminar stabilization should only be performed by surgeons who are experienced and have undergone training in the use of this device. Only surgeons who are familiar with the implant components, instruments, procedure, clinical applications, biomechanics, adverse events, and risks associated. A lack of adequate experience and/ or training may lead to a higher incidence of adverse events.

View this table:
[Table 1](https://www.ijssurgery.com/content/10/41/T1)

Table 1 
ICD-10-CM Diagnosis Codes.

## Summary

Surgeon expertise and proper patient selection are critical to determine the correct surgical treatment solution to address anatomical and pathological variation of patients with LSS. Decompression alone and decompression plus fusion are both established treatments for LSS. The choice to perform decompression alone, decompression with interlaminar stabilization, or decompression plus fusion is the discretionary purview of the spine surgeon and his/her patient.

Lumbar decompression with interlaminar stabilization is recommended for coverage in carefully selected lumbar spinal stenosis patients without gross instability or in which the decompression procedure itself may create iatrogenic instability. The procedure should be performed by a qualified and well-trained spine surgeon after completion of a thorough diagnostic evaluation, documented failure of nonsurgical management and taking into consideration appropriate anatomical and pathological considerations.

It is important for spine surgeons to be able to provide surgical solutions that have proven net health benefits for clearly defined, precisely diagnosed patient cohorts, which in parallel support fiscal responsibility of reducing overall costs to the healthcare system. Further, in considering the evolutionary healthcare environment, ISASS coverage guidance considers the increasing importance of value-based and bundled payment initiatives which incorporate clinical as well as economic value propositions. In select patients within the LSS continuum, decompression with interlaminar stabilization has proven to provide equivalent outcomes with a reduced cost compared to decompression plus fusion.14, 15 Additionally, for patients with significant back pain and associated advanced degenerative segmental disease, decompression with interlaminar stabilization provides benefits beyond decompression alone and may extend the durability of the decompression procedure (Table 2).

View this table:
[Table 2](https://www.ijssurgery.com/content/10/41/T2)

Table 2 
Publication Table.

## Disclosures

Richard Guyer, MD reports serving as a one-day Faculty Trainer for Paradigm Spine. Frank P. Cammisa, Jr., MD reports investments in Paradigm Spine. Michael Musacchio, MD reports consulting fees and speaking honoraria from Paradigm Spine and Medtronic LLC. Morgan P. Lorio, MD, FACS reports no disclosures.

*   Copyright © 2016 ISASS - This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery

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