Medicare Advantage

PEER-REVIEWED LITERATURE

Aggarwal and Chow (2021) stated that LSS is a condition of progressive neurogenic claudication that can be managed with lumbar decompression surgery or less invasive interspinous process devices if conservative therapy fails.  Popular interspinous process spacers include X-Stop, Vertiflex, and Coflex, with X-Stop being taken off market due to its adverse events profile.  These researchers carried out a disproportionality analysis to examine if a statistically significant signal exists in the interspinous spacers and the reported adverse events using the Manufacturer and User Facility Device Experience (MAUDE) database maintained by the U.S. Food and Drug Administration (FDA). Statistically significant signals were found with each of the three interspinous spacer devices (Coflex, Vertiflex, and X-Stop) and each of the following adverse events: fracture, migration, and pain/worsening symptoms. The authors concluded that further studies such as RCTs are needed to validate these findings.

 
In 2021, Welton et al. provided a retrospective review of 189 individuals who received lumbar level SISS compared with 378 individuals who underwent primary lumbar spine laminectomy or laminotomy. The authors concluded that rates of 30-day complications in the SISS group were not significantly different from individuals undergoing laminectomy or laminotomy. However, rates of 2-year device-specific complications within SISS and cumulative risk associated with these complications should be considered further as they likely represent need for additional procedures for an individual and substantial cost to the healthcare system. 

In 2021, Schenck et al evaluated five-year long-term results of a randomized controlled trial comparing conventional decompression and interspinous process devices. Short-term results provided evidence that the outcomes of IPD implantation were comparable to those of decompressive surgery, although the reoperation rate was higher in individuals who received an IPD. In total, 159 individuals were included in the trial with 80 individuals randomly assigned to undergo IPD implantation, and 79 underwent spinal bony decompression. The primary outcome was the Zurich Claudication Questionnaire (ZCQ) score at a five-year follow-up. The success rates in terms of ZCQ score were similar. The reoperation rate at two years after surgery was substantial in the IPD group (29%), but no reoperations were performed thereafter. Long-term visual analog scale score for back pain was lower in the IPD group than the bony decompression group. The authors concluded IPD implantation is a more expensive alternative to decompressive surgery but has comparable functional outcome during follow-up. The risk of reoperation due to absence of recovery is substantial in the first 2 years after IPD implantation, but if surgery is successful this positive effect remains throughout long-term follow-up. The IPD group had less back pain during long-term follow-up, but the clinical relevance of this finding is debatable.

In 2023, Ekhator et al performed a systematic review and meta-analysis of six studies to determine the effectiveness of the X-stop interspinous distractor compared to laminectomy. The goal of the systematic review was to identify the treatment that offers the maximum benefit with fewer complications to the patient. The secondary objective was to compare the success rates of both treatments by evaluating the quality of life of patients after the interventions. The success of the interventions were determined based on factors such as pain reduction, improvement in symptoms, mobility, and the likelihood of complications or disability. The meta-analysis focused on which treatment for lumbar spinal stenosis, particularly X-stop spinous distractors and laminectomy, was more effective by comparing their impacts on individuals and their livelihoods. The meta-analysis emphasized that a laminectomy is a more effective intervention for the treatment of lumbar spinal stenosis as it is more cost-effective and results in fewer complications in the long term.

A meta-analysis was conducted in 2023 by Xian et al. to investigate whether interspinous spacer (IS) results in better performance for individuals with lumbar spinal stenosis (LSS) when compared with decompressive surgery (DS).  Eight studies involving 852 individuals were included in the meta-analysis. The authors summarized IS had similar effects with DS in hospital stay, blood loss, spinous process fracture, disc height decrease, VAS score, Oswestry Disability Index score, and Zurich Claudication Questionnaire Symptom severity, and was better in some indices such as operation time, dural violation, Zurich Claudication Questionnaire Physical function, and foraminal height decrease than DS. However, due to the higher rate of reoperation in the IS group, both IS and DS were considered acceptable strategies for treating LSS. As a novel technique, further well-designed studies with longer-term follow-up are needed to evaluate the effectiveness and safety of IS.

Zhu and Xiao performed a systematic review and meta-analysis in 2024 to evaluate the effectiveness and safety of treatment with an interspinous process device (IPD) in comparison to traditional treatment. Interspinous process devices were used as a treatment in selected individuals with lumbar spinal stenosis (LSS). However, the use of IPD was still debated that it had significantly higher reoperation rates compared to traditional decompression. A total of 13 studies were included (5 RCTs and 8 retrospective studies) in the review. There was no significant difference of Oswestey Disability Index (ODI) score in the last post-procedure follow-up. There was significant difference of Visual Analog Scale (VAS) back pain scoring but there existed no significant difference of leg pain. However, IPD had higher device problems and lesser dural tears compared to traditional decompression. In conclusion of the study, although IPD had lower back pain score and lower dural tears compared with traditional decompression, current evidence indicated no superiority for individual-reported outcomes for IPD compared with alone decompression treatment. However, these findings need to be verified further by multicenter, double-blind and large sample RCTs.

In 2024, Han et al performed a systematic review and meta-analysis of randomized controlled trials to evaluate the efficacy and safety of an interspinous process device (IPD) in the treatment of degenerative lumbar spinal stenosis compared with decompression surgery. Five randomized controlled trials with 555 patients were included in the study. The Visual Analogue Scale and the Oswestry Disability Index were analyzed, as well as the Zurich Claudication Questionnaire for efficacy evaluation. Complication and reoperation rate was utilized for the assessment of safety. The authors concluded the systematic review and meta-analysis indicated no superiority in the clinical outcome for IPD compared with decompression surgery. However, more clinical studies are warranted to determine the efficacy and safety of IPD.

INTERLAMINAR DEVICES

An example of an interlaminar device used during spinal decompression is the Coflex® Interlaminar Stabilization® Technology implant (Paradigm Spine; New York, NY). This device was approved by the FDA in 2012 and is a single-piece dynamic stabilization device with pairs of wings that surround the superior and inferior spinous processes. The Coflex device is indicated for use in skeletally mature individuals with lumbar stenosis at one or two levels from L1 to L5, with at least moderate impairment in function refractory to at least 6 months of nonoperative treatment. The Coflex device is intended to be implanted midline between adjacent lamina of one or two contiguous lumbar motion segments. Interlaminar stabilization is performed after decompression of stenosis at the affected levels. 

PEER-REVIEWED LITERATURE

The number of complex fusions performed on Medicare individuals defined as ≥age 65, with lumbar spinal stenosis with or without spondylolisthesis has been increasing. Typically, these procedures are longer, more invasive and pose a greater risk for complications. Interlaminar stabilization (ILS) serves as an intermediary between decompression alone and decompression with fusion. Grinberg, et al. in 2020, performed a prospective, multicentered, randomized controlled trial comparing decompression with ILS to decompression with posterolateral fusion with bilateral pedicle screw instrumentation. At one or two levels, 84 individuals ≥age 65 underwent decompression with ILS, 57 individuals ≥age 65 underwent decompression with fusion, and 131 individuals <age 65 underwent decompression with ILS. Comparisons were made between ≥age 65 ILS individuals and ≥age 65 fusion individuals and between <age 65 and ≥age 65 ILS individuals. The individuals were assessed before and after surgery at six weeks and at intervals of three months to five years. The authors concluded ILS individuals ≥age 65 performed as well as both those receiving fusion and those <age 65 who received ILS. Importantly, however, for this older population, ILS Medicare individuals experienced less blood loss, a shorter operation and shorter hospital stay than fusion Medicare individuals.

Zhong et al in 2021 performed a retrospective cohort analysis to compare postoperative outcomes of Coflex interspinous device versus laminectomy. Coflex Interlaminar Stabilization device (CID) is indicated for one- or two-level lumbar stenosis with grade 1 stable spondylolisthesis in adult patients, as an alternative to laminectomy, or laminectomy and fusion. CID provides stability against progressive spondylolisthesis, retains motion, and prevents further disc space collapse. 83 individuals were included in the study. 37 cases of single-level laminectomy were compared to 46 single level CID. CID individuals had higher estimated blood loss (EBL), longer operative time and longer length of stay. Total perioperative complications and instrumentation-related complication was higher in the CID. The authors concluded single-level CID devices had higher perioperative 90-day complications, longer operative time, length of stay, higher EBL compared to laminectomies alone. Similar overall revision and neurologic complication rates were noted compared to laminectomy at last post-op follow-up.

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Interspinous devices (ISD) and interlaminar devices (ILD) are marketed as alternatives to conventional surgery for degenerative lumbar pathologies with comparisons to decompression-alone are limited. In 2024, Pennington et al. conducted a study to review the extant literature comparing cost-effectiveness of ISDs/ILDs to decompression alone. Outcomes were analyzed at 3 months, 6 months, 1 year, 2 years, and last follow-up (LFU). Twenty-nine studies were included in the final analysis. ILD/ISD showed greater leg pain improvement at 3 months, 6 months, and 1 year, but not in 2-year or last indicated follow-up. Back pain improvement was better following ISD/ILD only at 1 year. The ZCQ physical function scores improved more following decompression alone at 6 months and 12 months. ODI and EuroQol EQ-5D scores favored ILD/ISD at all time points except at 6 months. Reoperations and total care costs were higher in the ILD/ISD group; complications did not differ significantly between groups. The authors found outcomes were similar following decompression alone and ILD/ISD; the observed differences did not reach accepted minimum clinically important difference thresholds. ISD/ILDs have higher associated costs and reoperation rates, suggesting current evidence does not support ILD/ISDs as a cost-effective alternative to decompression alone.

A retrospective review of the Food and Drug Administration Manufacturer and User Facility Device Experience database was performed to describe the adverse events associated with interspinous process devices (IPDs) by Kazarian et al in 2024.  A total of 943 surgery-related adverse events were identified. The most common adverse events were implant malfunction, inadequate efficacy, implant migration, and fractures. Concerningly, these complications required revision surgery in one-third of cases when they had occurred. Implant-specific assessments demonstrated a high prevalence of implant malfunctions for the Coflex and Superion implants compared with traditional uninstrumented laminectomy for decompression. While these rarely led to revision surgery in the Superion, nearly 90% of Coflex implant malfunctions led to revision surgery.

A retrospective study performed in 2025 by Heo et al,  evaluated the long-term clinical usefulness and radiologic changes around the Coflex device following decompression with Coflex insertion for degenerative lumbar spinal stenosis (DLSS) with an average follow-up of fourteen years. The study included 147 individuals who underwent decompression and Coflex insertion for single-level DLSS at a single institution between January 2007 and December 2010. Individuals with spinal stenosis unresponsive to three months of conservative treatment were treated surgically. Intervertebral disc height and foramen height at the Coflex insertion site decreased by 5.3% and 2.0%, respectively, after surgery. The reoperation rate at the operated site was 25%. A significantly higher reoperation rate was observed in individuals with translational instability and angular instability. Eight individuals underwent reoperation due to rapid progression of instability within two years of Coflex insertion; thereafter, a similar cumulative incidence rate was consistently observed. The adjacent-segment rate was 10.8%. The authors found that th​e Coflex interspinous device helps preserve disc and foramen height but is associated with a high reoperation rate, particularly in individuals with spinal instability. Therefore, careful individual selection is crucial when considering its use.