Aperius interspinous implant versus open surgical decompression in lumbar spinal stenosis

doi:10.1016/j.spinee.2011.08.419

The Spine Journal

Volume 11, Issue 10, October 2011, Pages 933-939

https://doi.org/10.1016/j.spinee.2011.08.419 Get rights and content

Abstract

Background context

Few studies have analyzed the results of an interspinous distraction device in patients with lumbar spinal stenosis. It is still unknown whether the outcomes of an interspinous implant are related to the severity of stenosis.

Purpose

To determine the success rate of the Aperius implant and open decompression with the aim of defining better the indications for the two modalities of treatment.

Study design

Comparison of two cohorts of patients with moderate or severe stenosis treated with the Aperius or by open decompression.

Patient sample

The sample comprises 36 patients who had the Aperius implant and 35 who underwent open decompression, both groups followed prospectively. In the two cohorts, central or lateral stenosis was present in similar proportions, and in both, the patients had pure intermittent claudication or symptoms at rest and on walking. In both groups, preoperative diagnosis was made by magnetic resonance imaging (MRI).

Outcome measures

Patients of both groups were evaluated with the Zurich Claudication Questionnaire (ZCQ) and Oswestry Disability Index. The results were rated as good or poor based on the ZCQ.

Methods

The patients of both cohorts were evaluated at 1 month and 3, 6, and 12 months after operation, the final follow-up being carried out at least 2 years after surgery. Severity of stenosis was determined based on preoperative MRI scans. In 17 patients of the Aperius group, MRI studies were repeated at the 6-month or final follow-up and compared with the preoperative studies.

Results

Of the patients in the Aperius group, six had removal of the implant and open surgical decompression at 2 to 17 months after operation; these patients were considered to have a poor result. At the final follow-up, the result was rated as good in 47% of all patients who had had the Aperius implant. The percentage of good outcomes was 60% in moderate stenosis and 31% in severe stenosis. When considering all not reoperated patients, 57% had good outcomes; however, if only the scores in the patient satisfaction domain of the ZCQ were considered, 67% of these patients were somewhat satisfied with the result of Aperius. No significant relationship was found between patients with pure intermittent claudication and those with leg symptoms also at rest. In 71% of cases in which preoperative and postoperative MRIs were compared, no significant change in size of the spinal canal was found after operation, whereas in the remaining patients a slight increase in size of the canal was detected. In the open decompression cohort, the results were good in 80% of cases and poor in 20%. The outcomes were satisfactory in 69% of moderate stenosis, with no significant difference with the similar subgroup of the Aperius series. In severe stenosis, the 89% rate of good results was significantly higher than in the severe Aperius subgroup (p<.0001).

Conclusions

The Aperius interspinous implant is poorly indicated for severe lumbar stenosis, which is significantly improved only in a small minority of cases, whereas decompression procedures ensure high chances of good results. The implant may be indicated for selected patients with moderate stenosis. The outcomes of the Aperius are not influenced by the type of clinical presentation of lumbar stenosis.

Introduction

Evidence & Methods

Interspinous spacers for spinal stenosis were initially developed as an alternative for patients medically unfit for open decompression. However, their use has expanded in some centers to be considered a general alternative to open decompression for the treatment of lumbar spinal canal stenosis. This matched-cohort study compares these two approaches.

For patients with moderate or severe stenosis, respectively, the interspinous device provided good outcomes in 60% and 31% of patients as measured by the Zurich Claudication Questionnaire (ZCQ). Following open decompression, results were good in 69% and 89%, respectively. Seventeen percent of the interspinous spacers required removal and revision to open decompression.

This independent study suggests that in cases of severe stenosis, open decompression affords better results than interspinous spacers. In light of reliably good outcomes with open decompression (as demonstrated in the SPORT and Maine spinal stenosis studies), the role for interspinous devices as a general treatment for lumbar spinal stenosis is yet to be determined.

—The Editors

The standard operative procedure for lumbar spinal stenosis is open surgical decompression. The first interspinous process implant was developed by Senegas et al. [1], who used the device also in lumbar stenosis but only to stabilize the motion segment after open decompression. In previous years, several interspinous devices have been developed to obtain indirect decompression of neural structures in lumbar stenosis by posterior segmental distraction. The most often used implant has been the X-Stop, which is inserted by an open approach centered on the interspinous space [2], [3], [4], [5], [6], [7], [8].

The Aperius, introduced in the clinical practice in 2007 (Medtronic, Memphis, TN, USA), has been the first interspinous device developed to be implanted percutaneously, usually under local anesthesia.

During the past few years, there has been a widespread use of the interspinous spacers in patients with central or lateral lumbar stenosis of any severity. But, the clinical results of these devices, implanted by open surgery or percutaneously, are still controversial [2], [3], [6], [7], [8]. Furthermore, only one study [9], carried out on very small groups of patients, compared the X-Stop with open decompression.

We compared the results of the Aperius implant with those of open decompression with the aim to better define the indications for the two types of procedures in patients with lumbar stenosis.

Section snippets

Aperius

From September 2007 to April 2008, 36 consecutive patients with lumbar stenosis were treated with the Aperius and followed prospectively. Exclusion criteria in 20 other cases were severe motor deficits (muscle strength less than or equal to 3 of 5), spinal stenosis at greater than two levels, degenerative spondylolisthesis (DS) greater than or equal to 15%, degenerative scoliosis, or severe osteoporosis (total T score in the lumbar spine less than or equal to 3 with dual-energy X-ray

Aperius

Stenosis was moderate in 20 cases and severe in 16. The type of stenosis is reported in Table 1 and the severity of narrowing as related to the type of stenosis in Table 2. Of the six patients who underwent open surgery, two had moderate stenosis and four had severe stenosis; in these patients, the result was rated as poor.

The mean preoperative and postoperative scores in the ZCQ and ODI of the 31 not reoperated patients are reported in Table 3. The rate of good results was slightly higher at

Discussion

Interspinous spacers have been used in various degenerative diseases on the lumbar spine [12]. However, few studies have analyzed the results of implantation of a spacer, with no additional neural decompression, in lumbar stenosis, and in all trials, the X-Stop was used [2], [3], [4], [5], [6], [7], [8], [9], [12], [13], [14]. Zucherman et al. [2], in a prospective randomized multicenter study evaluating the 1-year outcome of the interspinous implant using the ZCQ, reported a success rate of

References (20)

G. Stucki et al.
Relative responsiveness of condition- specific and generic health status measures in degenerative lumbar stenosis
J Clin Epidemiol
(1995)
J. Senegas et al.
Recalibration of the lumbar canal as an alternative to laminectomy in the treatment of lumbar canal stenosis
Rev Chir Orthop Reparatrice Appar Mot
(1998)
J.F. Zucherman et al.
A prospective randomized multi-center study for treatment of lumbar spinal stenosis with the X STOP interspinous implant: 1-year result
Eur Spine J
(2004)
J.F. Zucherman et al.
A multicenter, prospective, randomized trial evaluating the X STOP interspinous process decompression system for the treatment of neurogenic intermittent claudication: two-year follow-p results
Spine
(2005)
P.A. Anderson et al.
Treatment of neurogenic claudication by interspinous decompression: application of the X-STOP device in patients with lumbar degenerative spondylolisthesis
J Neurosurg Spine
(2006)
D. Kondrashov et al.
Interspinous process decompression with the X-STOP device for lumbar spinal stenosis: a 4-year clinical follow-up study
J Spinal Disord Tech
(2006)
M. Siddiqui et al.
One-year results of X-STOP interspinous implant for treatment of lumbar spinal stenosis
Spine
(2007)
P. Brussee et al.
Self-rated evaluation of outcome of the implantation of interspinous process distraction (X-Stop) for neurogenic claudication
Eur Spine J
(2008)
J.O. Verhoof et al.
High failure rate of the interspinous distraction device (X-Stop) for the treatment of lumbar spinal stenosis caused by degenerative spondylolisthesis
Eur Spine J
(2008)
D.G. Kondrashov et al.
X-STOP versus decompression for neurogenic claudication: economic and clinical analysis
Internet J Minim Invasive Spinal Tech
(2007)

There are more references available in the full text version of this article.

Cited by (31)

Decompression Alone Versus Interspinous/Interlaminar Device Placement for Degenerative Lumbar Pathologies: Systematic Review and Meta-Analysis
2024, World Neurosurgery
Interspinous devices (ISDs) and interlaminar devices (ILDs) are marketed as alternatives to conventional surgery for degenerative lumbar conditions; comparisons with decompression alone are limited. The present study reviews the extant literature comparing the cost and effectiveness of ISDs/ILDs with decompression alone.
Articles comparing decompression alone with ISD/ILD were identified; outcomes of interest included general and disease-specific patient-reported outcomes, perioperative complications, and total treatment costs. Outcomes were analyzed at <6 weeks, 3 months, 6 months, 1 year, 2 years, and last follow-up. Analyses were performed using random effects modeling.
Twenty-nine studies were included in the final analysis. ILD/ISD showed greater leg pain improvement at 3 months (mean difference, −1.43; 95% confidence interval, [−1.78, −1.07]; P < 0.001), 6 months (−0.89; [−1.55, −0.24]; P = 0.008), and 12 months (−0.97; [−1.25, −0.68]; P < 0.001), but not 2 years (P = 0.22) or last follow-up (P = 0.09). Back pain improvement was better after ISD/ILD only at 1 year (−0.87; [−1.62, −0.13]; P = 0.02). Short-Form 36 physical component scores or Zurich Claudication Questionnaire (ZCQ) symptom severity scores did not differ between the groups. ZCQ physical function scores improved more after decompression alone at 6 months (0.35; [0.07, 0.63]; P = 0.01) and 12 months (0.23; [0.00, 0.46]; P = 0.05). Oswestry Disability Index and EuroQoL 5 dimensions scores favored ILD/ISD at all time points except 6 months (P = 0.07). Reoperations (odds ratio, 1.75; [1.23, 2.48]; P = 0.002) and total care costs (standardized mean difference, 1.19; [0.62, 1.77]; P < 0.001) were higher in the ILD/ISD group; complications did not differ significantly between the groups (P = 0.41).
Patient-reported outcomes are similar after decompression alone and ILD/ISD; the observed differences do 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.
Which is the most effective treatment for lumbar spinal stenosis: Decompression, fusion, or interspinous process device? A Bayesian network meta-analysis
2021, Journal of Orthopaedic Translation
Citation Excerpt :
In the past two decades, interspinous process devices (IPD) such as Coflex, X-Stop, and DIAM are designed and applied for LSS. Such posterior segmental distractions obtain symptom improvement by indirect decompression of neural structures [7]. LSS related symptoms, including neurogenic claudication, can be alleviated by limiting lumbar extension mechanically and enlarging the spinal canal by increasing flexion [8].
To compare the clinical efficacy, complications, and reoperation rates among three major treatments for lumbar spinal stenosis (LSS): decompression, fusion, and interspinous process device (IPD), using a Bayesian network meta-analysis.
Databases including Pubmed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science were used for the literature search. Randomized Controlled Trials (RCTs) with three treatment methods were reviewed and included in the study. R software (version 3.6.0), Stata (version 14.0), and Review Manager (version 5.3) were used to perform data analysis.
A total of 10 RCTs involving 1254 patients were enrolled in the present study and each study met an acceptable quality according to our quality assessment described later. In direct comparison, IPD exhibited a higher incidence of reoperation than fusion (OR = 2.93, CI: 1.07–8.02). In indirect comparison, the rank of VAS leg (from best to worst) was as follows: IPD (64%) > decompression (25%) > fusion (11%), and the rank of ODI (from best to worst) was: IPD (84%) > fusion (13%) > decompression (4%). IPD had the lowest incidence of complications; the rank of complications (from best to worst) was: IPD (60%) > decompression (27%) > fusion (14%). However, for the rank of reoperation, fusion showed the best results (from best to worst): fusion (79%) > decompression (20%) > IPD (1%). Consistency tests at global and local level showed satisfactory results and heterogeneity tests using loop text indicated a favorable stability.
The present study preliminarily indicates that non-fusion methods including decompression and IPD are optimal choices for treating LSS, which achieves favorable clinical outcomes. IPD exhibits a low incidence of complications, but its high rate of reoperation should be treated with caution.
For the treatment of LSS, several procedures including decompression, fusion, and IPD have been reported. However, each method has its own advantages and disadvantages. To date, the golden standard treatment for LSS is still controversial. In this network meta-analysis, our results demonstrate that both decompression and IPD obtain satisfactory clinical effects for LSS. IPD is accompanied with a low incidence of complications, however, its high rate of reoperation should be acknowledged with discretion.
Adult lumbar spondylolisthesis: Interspinous devices
2020, Seminars in Spine Surgery
Citation Excerpt :
Please provide these details). Furthermore, direct decompression group was significantly better for patient cohorts with more severe stenosis.35 Richter et al. found no significant difference in patient reported outcomes in patients who underwent direct decompression alone versus patients who underwent direct decompression augmented with Coflex.36,37
As minimally invasive surgery has become increasingly popular, interspinous process devices (IPDs) have evolved beyond cases of simple focal spinal stenosis. Despite design differences, all IPDs aim to achieve indirect decompression of the nerve roots by enlarging the caliber of the neural foramina via distraction of the adjacent spinous processes. Whether IPDs reduce the risk of adjacent level stenosis compared to decompression and fusion for degenerative spondylolisthesis remains unclear. Ultimately, the paucity of high-quality, long-term, comparative, clinical studies precludes any strong recommendation for the use of IPDs for the treatment of degenerative spondylolisthesis.
Understanding the value of minimally invasive procedures for the treatment of lumbar spinal stenosis: the case of interspinous spacer devices
2018, Spine Journal
Citation Excerpt :
Excluding the results of this higher center, the reoperation rate is 15% at 2 years for 39 patients, which is closer to our 2-year cumulative reoperation rate of 16.3%. A few recent studies have observed lower reoperation rates (2%–16%) than we observed in the MedPAR data [6,25–28]. The highest reoperation rates, ranging from 41.7% at 2 years [29] to 85% at 4 years [21], have been reported in studies with very few participants (<15) [19,30].
Minimally invasive lumbar spinal stenosis procedures have uncertain long-term value.
This study sought to characterize factors affecting the long-term cost-effectiveness of such procedures using interspinous spacer devices (“spacers”) relative to decompression surgery as a case study.
Model-based cost-effectiveness analysis.
The Medicare Provider Analysis and Review database for the years 2005–2009 was used to model a group of 65-year-old patients with spinal stenosis who had no previous spine surgery and no contraindications to decompression surgery.
Costs, quality-adjusted life years (QALYs), and cost per QALY gained were the outcome measures.
A Markov model tracked health utility and costs over 10 years for a 65-year-old cohort under three care strategies: conservative care, spacer surgery, and decompression surgery. Incremental cost-effectiveness ratios (ICER) reported as cost per QALY gained included direct medical costsfor surgery. Medicare claims data were used to estimate complication rates, reoperation, and related costs within 3 years. Utilities and long-term reoperation rates for decompression were derived frompublished studies. Spacer failure requiring reoperation beyond 3 years and post-spacer health utilities are uncertain and were evaluated through sensitivity analyses. In the base-case, the spacer failure rate was held constant for years 4–10 (cumulative failure: 47%). In a “worst-case” analysis, the 10-year cumulative reoperation rate was increased steeply (to 90%). Threshold analyses were performed to determine the impact of failure and post-spacer health utility on the cost-effectiveness of spacer surgery.
The spacer strategy had an ICER of $89,500/QALY gained under base-case assumptions, and remained under $100,000 as long as the 10-year cumulative probability of reoperation did not exceed 54%. Under worst-case assumptions, the spacer ICER was $482,000/QALY and fell below $100,000 only if post-spacer utility was 0.01 greater than post-decompression utility or the cost of spacer surgery was $1,600 less than the cost of decompression surgery.
Spacers may provide a reasonably cost-effective initial treatment option for patients with lumbar spinal stenosis. Their value is expected to improve if procedure costs are lower in outpatient settings where these procedures are increasingly being performed. Decision analysis is useful for characterizing the long-term cost-effectiveness potential for minimally invasive spinal stenosis treatments and highlights the importance of complication rates and prospective health utility assessment.
Interspinous device versus laminectomy for lumbar spinal stenosis: A comparative effectiveness study
2014, Spine Journal
Citation Excerpt :
Many complications and reoperations after ID, however, may be prevented with better patient selection (ie, by selecting out those without severe stenosis, grade I spondylolisthesis, adjacent level disease, and/or severe foraminal stenosis) [5]. In such cases, laminectomy likely affords better results than IDs [27]. Reoperation rates for IDs range from 4.6% to as high as 85% in studies with long-term follow-up [5,20].
Currently no studies directly compare effectiveness between interspinous devices (IDs) and laminectomy in lumbar spinal stenosis (LSS) patients.
To compare reoperations, complications, and costs between LSS patients undergoing ID placement versus laminectomy.
Retrospective comparative study.
The MarketScan database (2007–2009) was queried for adults with LSS undergoing ID placement as a primary inpatient procedure.
Reoperation rates, complication rates, and costs.
Each ID patient was matched with a laminectomy patient using propensity score matching. Reoperations, complications, and costs were analyzed in patients with at least 18 months postoperative follow-up. The authors did not receive funding from any external sources for this study.
Among 498 inpatients that underwent ID placement between 2007 and 2009; the average age was 73 years. The cumulative reoperation rates after ID at 12 and 18 months were 21% and 23%, respectively. The average inpatient hospitalization lasted 1.6 days with an associated cost of $17,432. Two propensity-matched cohorts of 174 patients that had undergone ID versus laminectomy were analyzed. Longer length of stay was observed in the laminectomy cohort (2.5 days vs. 1.6 days, p<.0001), whereas ID patients accrued higher costs at index hospitalization ($17,674 vs. $12,670, p=.0001). Index hospitalization (7.5% vs. 3.5%, p=.099) and 90-day (9.2% vs. 3.5%, p=.028) complications were higher in the laminectomy cohort compared with the ID cohort. The ID patients had significantly higher reoperation rates than laminectomy patients at 12 months follow-up (12.6% vs. 5.8%, p=.026) and incurred higher cumulative costs than laminectomy patients at 12 months follow-up ($39,173 vs. $34,324, p=.289).
Twelve-month reoperation rates and index hospitalization costs were significantly higher among patients who underwent ID compared with laminectomy for LSS.
Validity of outcome measures used in randomized clinical trials and observational studies in degenerative lumbar spinal stenosis
2023, Scientific Reports

View all citing articles on Scopus

: FDA device/drug status: Approved by the European Community (EC). Medtronic made no FDA approval request.

: Author disclosures: RP: Nothing to disclose. EF: Nothing to disclose. GC: Nothing to disclose. PPMM: Nothing to disclose. FP: Nothing to disclose.

View full text

Clinical StudyAperius interspinous implant versus open surgical decompression in lumbar spinal stenosis

Abstract

Background context

Purpose

Study design

Patient sample

Outcome measures

Methods

Results

Conclusions

Introduction

Section snippets

Aperius

Aperius

Discussion

J Clin Epidemiol

Recalibration of the lumbar canal as an alternative to laminectomy in the treatment of lumbar canal stenosis

Rev Chir Orthop Reparatrice Appar Mot

A prospective randomized multi-center study for treatment of lumbar spinal stenosis with the X STOP interspinous implant: 1-year result

Eur Spine J

A multicenter, prospective, randomized trial evaluating the X STOP interspinous process decompression system for the treatment of neurogenic intermittent claudication: two-year follow-p results

Spine

Treatment of neurogenic claudication by interspinous decompression: application of the X-STOP device in patients with lumbar degenerative spondylolisthesis

J Neurosurg Spine

Interspinous process decompression with the X-STOP device for lumbar spinal stenosis: a 4-year clinical follow-up study

J Spinal Disord Tech

One-year results of X-STOP interspinous implant for treatment of lumbar spinal stenosis

Spine

Self-rated evaluation of outcome of the implantation of interspinous process distraction (X-Stop) for neurogenic claudication

Eur Spine J

High failure rate of the interspinous distraction device (X-Stop) for the treatment of lumbar spinal stenosis caused by degenerative spondylolisthesis

Eur Spine J

X-STOP versus decompression for neurogenic claudication: economic and clinical analysis

Internet J Minim Invasive Spinal Tech

Clinical Study
Aperius interspinous implant versus open surgical decompression in lumbar spinal stenosis