Effectiveness of interspinous implant surgery in patients with intermittent neurogenic claudication: a systematic review and meta-analysis

Sirtuin 1 Is a Potential Target for the Treatment of Neurogenic Intermittent Claudication by Modulating Pyroptosis

Neurogenic intermittent claudication (NIC) pathogenesis associated with lumbar spinal stenosis (LSS) remains unclear. However, pyroptosis has been implicated in the pathogenesis of various central nervous system disorders. Therefore, the present study aimed to explore the potential role of pyroptosis in NIC progression. Additionally, the present study investigated the possible involvement of Sirtuin 1 (Sirt1), a protein recognized for its neuroprotective properties, in mitigating the progression of NIC by alleviating pyroptosis. In the current study, a rat model of NIC associated with LSS was successfully constructed by inserting a silicone strip into the vertebral plates. The Basso Beattie Bresnahan score was employed to assess the motor function of rats. Western blot analysis was performed to measure the levels of pyroptosis-related proteins in rat spinal cord tissue. Meanwhile, PC-12 cells were cultured with H2O2 to establish an in vitro model of oxidative stress, allowing to investigate the effects of Sirt1 on cell pyroptosis and oxidative stress in H2O2-treated cells. The current results showed that rats with NIC developed both motor and sensory dysfunction. Additionally, NIC surgery notably elevated NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD (ASC), gasdermin D N-terminal (GSDMD-N), and IL-1β levels in the spinal cord tissues of rats, suggesting that pyroptosis is activated in the context of NIC. Significantly, downregulation of Sirt1 exacerbated malondialdehyde and reactive oxygen species levels, and simultaneously reduced GSH levels in H2O2-stimulated PC-12 cells, suggesting that Sirt1 deficiency can aggravate oxidative stress. Meanwhile, downregulation of Sirt1 also led to increased levels of NLRP3, ASC, GSDMD-N, and cleaved caspase 1 in H2O2-stimulated PC-12 cells, suggesting that Sirt1 deficiency can further enhance the pyroptosis in these cells. Targeting pyroptosis signaling may yield new insights into the treatment of NIC. The mechanisms mediated by pyroptosis could offer valuable perspectives on the pathogenesis and management of this condition.

Comparative Analysis of Early and Long-Term Outcomes of Patients with Degenerative Lumbar Spine Disease Using the DIAM Stabilizer and Standard Rehabilitation Program: A Preliminary Prospective Randomized Controlled Trial with 1-Year Follow-Up

Low back pain (LBP) is a leading cause of disability and work absenteeism. The cause of LBP may be degeneration of the intervertebral disc. LBP is characterized by considerable variability and tends to develop into chronic pain. Treatment of LBP includes conservative and rehabilitative treatments, surgery, and so-called minimally invasive treatment. One of the most commonly performed procedures is interspinous stabilization using a dynamic interspinous DIAM (device for intervertebral assisted motion) stabilizer. There is still no clear, strong evidence for the effectiveness and superiority of surgical treatment over conservative treatment. This study aimed to compare the early and long-term outcomes of patients with LBP using the DIAM interspinous stabilizer in relation to patients treated conservatively. A group of 86 patients was prospectively randomized into two comparison groups: A (n = 43), treated with the DIAM dynamic stabilizer for degenerative lumbar spine disease (mean age = 43.4 years ± SD = 10.8 years), and B (n = 43), treated conservatively. Pain severity was assessed using the visual analog scale (VAS), whereas disability was assessed using the Oswestry disability index (ODI). The difference in preoperative and postoperative ODI scores ≥ 15 points was used as a criterion for treatment effectiveness, and the difference in VAS scores ≥ 1 point was used as a criterion for pain reduction. In patients under general anesthesia, the procedure only included implantation of the DIAM system. Patients in the control group underwent conservative treatment, which included rehabilitation, a bed regimen, analgesic drug treatment and periarticular spinal injections of anti-inflammatory drugs. It was found that all patients (n = 43) continued to experience LBP after DIAM implantation (mean VAS score of 4.2). Of the 36 patients who experienced LBP with sciatica before the procedure, 80.5% (n = 29) experienced a reduction in pain. As for the level of fitness, the average ODI score was 19.3 ± 10.3 points. As for the difference in ODI scores in the pre-treatment results vs. after treatment, the average score was 9.1 ± 10.6. None of the patients required reoperation at 12 months after surgery. There were no statistically significant differences between the two groups in either early (p = 0.45) or long-term outcomes (p = 0.37). In conclusion, neurosurgical treatment with the DIAM interspinous stabilizer was as effective as conservative treatment and rehabilitation during the one-year follow-up period.

Validity of outcome measures used in randomized clinical trials and observational studies in degenerative lumbar spinal stenosis

It is unclear whether outcome measures used in degenerative lumbar spinal stenosis (DLSS) have been validated for this condition. Cross-sectional analysis of studies for DLSS included in systematic reviews (SA) and meta-analyses (MA) indexed in the Cochrane Library. We extracted all outcome measures for pain and disability. We assessed whether the studies provided external references for the validity of the outcome measures and the quality of the validation studies. Out of 20 SA/MA, 95 primary studies used 242 outcome measures for pain and/or disability. Most commonly used were the VAS (n = 69), the Oswestry Disability Index (n = 53) and the Zurich Claudication Questionnaire (n = 22). Although validation references were provided in 45 (47.3%) primary studies, only 14 validation studies for 9 measures (disability n = 7, pain and disability combined n = 2) were specifically validated in a DLSS population. The quality of the validation studies was mainly poor. The Zurich Claudication Questionnaire was the only disease specific tool with adequate validation for assessing treatment response in DLSS. To compare results from clinical studies, outcome measures need to be validated in a disease specific population. The quality of validation studies need to be improved and the validity in studies adequately cited.

Interspinous process device versus conventional decompression for lumbar spinal stenosis: 5-year results of a randomized controlled trial

OBJECTIVE

Interspinous process distraction devices (IPDs) can be implanted to treat patients with intermittent neurogenic claudication (INC) due to lumbar spinal stenosis. 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 patients who received an IPD. This study focuses on the long-term results.

METHODS

Patients with INC and spinal stenosis at 1 or 2 levels randomly underwent either decompression or IPD implantation. Patients were blinded to the allocated treatment. The primary outcome was the Zurich Claudication Questionnaire (ZCQ) score at 5-year follow-up. Repeated measurement analysis was applied to compare outcomes over time.

RESULTS

In total, 159 patients were included and randomly underwent treatment: 80 patients were randomly assigned to undergo IPD implantation, and 79 underwent spinal bony decompression. At 5 years, the success rates in terms of ZCQ score were similar (68% of patients who underwent IPD implantation had a successful recovery vs 56% of those who underwent bony decompression, p = 0.422). The reoperation rate at 2 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 (p = 0.02).

CONCLUSIONS

IPD implantation is a more expensive alternative to decompressive surgery for INC 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.

A Differential Clinical Benefit Examination of Full Lumbar Endoscopy vs Interspinous Process Spacers in the Treatment of Spinal Stenosis: An Effect Size Meta-Analysis of Clinical Outcomes

STUDY DESIGN

A design-agnostic standardized effect meta-analysis of 48 randomized, prospective, and retrospective studies on clinical outcomes with spinal endoscopic and interspinous process spacer (IPS) surgery.

OBJECTIVE

The study aimed to provide reference set of Oswestry Disability Index (ODI) and visual analog scale (VAS) effect size data for back and leg pain following endoscopic and IPS decompression for lumbar herniated disc, foraminal, or lateral recess spinal stenosis.

BACKGROUND

Mechanical low back pain following endoscopic transforaminal decompression may be more reliably reduced by simultaneous posterior column stabilization with IPS.

METHODS

A systematic search of the PubMed, EMBASE, Web of Science, and the Cochrane Central Register of Controlled Trials from 1 January 2000 to 2 April 2020, identified 880 eligible endoscopy and 362 IPS studies varying in design and metrics. The authors compared calculated standardized effect sizes (Cohen's d) for extracted ODI, VAS-back, and VAS-leg data.

RESULTS

The pooled standardized effect size combining the ODI, VAS-back, and VAS-leg data for the total sample of 19862 data sets from the 30 endoscopy and 18 IPS was 0.877 (95% CI = 0.857-0.898). When stratified by surgery, the combined effect sizes were 0.877 (95% CI = 0.849-0.905) for endoscopic decompression and 0.863 (95% CI = 0.796-0.930; P = 0.056) for IPS implantation. The ODI effect sizes calculated on 6462 samples with directly visualized endoscopic decompression were 0.917 (95% CI = 0.891-0.943) versus 0.798 (95% CI = 0.713-0.883; P < 0.001) with indirect IPS decompression (P < 0.001). The VAS-back effect sizes calculated on 3672 samples were 0.661 (95% CI = 0.585-0.738) for endoscopy and 0.784 (95% CI: 0.644-0.923; P = 0.187) for IPS. The VAS-leg effect sizes calculated on 7890 samples were 0.885 (95% CI = 0.852-0.917) for endoscopic decompression and 0.851 (95% CI = 0.767-0.935; P = 0.427).

CONCLUSION

Lumbar IPS implantation produces larger reduction in low back pain than spinal endoscopy. On the basis of this meta-analysis, the combination of lumbar transforaminal endoscopy with simultaneous IPS has merits and should be formally investigated in higher grade clinical studies.

CLINICAL RELEVANCE

Meta-analysis on the added clinical benefit of combining lumbar endoscopic decompression with an interspinous process spacer.

Evaluation of Effectiveness of Treatment Strategies for Degenerative Lumbar Spinal Stenosis: A Systematic Review and Network Meta-Analysis of Clinical Studies

OBJECTIVE

Lumbar spinal stenosis (LSS) is a common disease in spinal surgery. Many related treatment methods have been reported, but their effectiveness still lacks a systematic comparison. We aimed to evaluate the clinical outcomes related to the efficacy and safety of these treatment strategies via a network meta-analysis.

METHODS

Relevant clinical studies were retrieved from the databases of PubMed, Embase, Web of Science, and Cochrane library updated to July 29, 2020. The data were extracted from the eligible literature and the results were presented as standardized mean differences with 95% confidence intervals (CIs). A network meta-analysis was executed using the netmeta, rjags, and gemtc packages in R software, and Begg and Egger tests were used to assess the publication bias within the included studies.

RESULTS

A total of 21 eligible studies based on 2890 patients with degenerative LSS were included. The newer microdecompression technique (bilateral decompression via unilateral laminotomy [BDUL]) performed better in decreasing the visual analog scale (VAS) score compared with conventional decompressive laminectomy (VAS score back pain, 1.22; 95% CI, 0.28-2.17; VAS score leg pain, 1.39; 95% CI, 0.82-1.96), but its Oswestry Disability Index improvement was slightly inferior to that of posterolateral fusion.

CONCLUSIONS

BDUL could effectively alleviate VAS pain of patients, and had a lower incidence of complications. Although BDUL was slightly inferior to posterolateral fusion in terms of Oswestry Disability Index improvement, the postoperative quality of life of patients treated with BDUL had been significantly improved compared with that before surgery.

Decompression alone versus fusion and Coflex in the treatment of lumbar degenerative disease: A network meta-analysis

BACKGROUND

Lumbar degenerative disease (LDD) is a very common disease. And decompression alone, posterior lumbar interbody fusion (PLIF), and interspinous device (Coflex) are generally accepted surgical techniques. However, the effectiveness and safety of the above techniques are still not clear. Network meta-analysis a comprehensive technique can compare multiple treatments based on indirect dates and all interventions are evaluated and ranked simultaneously. To figure out this problem and offer a better choice for LDD, we performed this network meta-analysis.

METHODS

PubMed and WanFang databases were searched based on the following key words, "Coflex," "decompression," "PLIF," "Posterior Lumbar Interbody Fusion," "Coflex" "Lumbar interbody Fusion." Then the studies were sorted out on the basis of inclusion criteria and exclusion criteria. A network meta-analysis was performed using The University of Auckland, Auckland city, New Zealand R 3.5.3 software.

RESULTS

A total of 10 eligible literatures were finally screened, including 946 patients. All studies were randomized controlled trials (RCTs). Compared with decompression alone group, there were no significant differences of Oswestry Disability Index (ODI) in Coflex and lumbar interbody fusion groups after surgery. However, Coflex and PLIF were better in decreasing Visual Analogue Scale (VAS) score compared with decompression alone. Furthermore, we found Coflex have a less complication incidence rate.

CONCLUSION

Compared with decompression alone, Coflex and lumbar interbody fusion had the similar effectiveness in improving lumbar function and quality of life. However, the latter 2 techniques were better in relieving pain. Furthermore, Coflex included a lower complication incidence rate. So we suggested that Coflex technique was a better choice to cue lumbar spinal stenosis (LSS).

LEVEL OF EVIDENCE

Systematic review and meta-analysis, level I.

SUcceSS, SUrgery for Spinal Stenosis: protocol of a randomised, placebo-controlled trial

INTRODUCTION

Central lumbar spinal stenosis (LSS) is a common cause of pain, reduced function and quality of life in older adults. Current management of LSS includes surgery to decompress the spinal canal and alleviate symptoms. However, evidence supporting surgical decompression derives from unblinded randomised trials with high cross-over rates or cohort studies showing modest benefits. This protocol describes the design of the SUrgery for Spinal Stenosis (SUcceSS) trial -the first randomised placebo-controlled trial of decompressive surgery for symptomatic LSS.

METHODS AND ANALYSIS

SUcceSS will be a prospectively registered, randomised placebo-controlled trial of decompressive spinal surgery. 160 eligible participants (80 participants/group) with symptomatic LSS will be randomised to either surgical spinal decompression or placebo surgical intervention. The placebo surgical intervention is identical to surgical decompression in all other ways with the exception of the removal of any bone or ligament. All participants and assessors will be blinded to treatment allocation. Outcomes will be assessed at baseline and at 3, 6, 12 and 24 months. The coprimary outcomes will be function measured with the Oswestry Disability Index and the proportion of participants who have meaningfully improved their walking capacity at 3 months postrandomisation. Secondary outcomes include back pain intensity, lower limb pain intensity, disability, quality of life, anxiety and depression, neurogenic claudication score, perceived recovery, treatment satisfaction, adverse events, reoperation rate and rehospitalisation rate. Those who decline to be randomised will be invited to participate in a parallel observational cohort. Data analysis will be blinded and by intention to treat. A trial-based cost-effectiveness analysis will determine the potential incremental cost per quality-adjusted life year gained.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the NSW Health (reference:17/247/POWH/601) and the Monash University (reference: 12371) Human Research Ethics Committees. Dissemination of results will be via journal articles and presentations at national and international conferences.

TRIAL REGISTRATION NUMBER

ACTRN12617000884303; Pre-results.

Coflex interspinous implant placement leading to synovial cyst development: case report

Interspinous process devices (IPDs) have been developed as less-invasive alternatives to spinal fusion with the goal of decompressing the spinal canal and preserving segmental motion. IPD implantation is proposed to treat symptoms of lumbar spinal stenosis that improve during flexion. Recent indications of IPD include lumbar facet joint syndrome, which is seen in patients with mainly low-back pain. Long-term outcomes in this subset of patients are largely unknown. The authors present a previously unreported complication of coflex (IPD) placement: the development of a large compressive lumbar synovial cyst. A 64-year-old woman underwent IPD implantation (coflex) at L4-5 at an outside hospital for low-back pain that occasionally radiates to the right leg. Postoperatively, her back and right leg pain persisted and worsened. MRI was repeated and showed a new, large synovial cyst at the previously treated level, severely compressing the patient's cauda equina. Four months later, she underwent removal of the interspinous process implant, bilateral laminectomy, facetectomy, synovial cyst resection, interbody fusion, and stabilization. At the 3-month follow-up, she reported significant back pain improvement with some residual leg pain. This case suggests that facet arthrosis may not be an appropriate indication for placement of coflex.

Understanding the value of minimally invasive procedures for the treatment of lumbar spinal stenosis: the case of interspinous spacer devices

BACKGROUND CONTEXT

Minimally invasive lumbar spinal stenosis procedures have uncertain long-term value.

PURPOSE

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.

STUDY DESIGN

Model-based cost-effectiveness analysis.

PATIENT SAMPLE

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.

OUTCOME MEASURES

Costs, quality-adjusted life years (QALYs), and cost per QALY gained were the outcome measures.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Development of Bilateral Facet Cysts Causing Recurrent Symptoms After Decompression and the Placement of an Intralaminar Implant: A Case Report

CASE

We report the development of bilateral symptomatic facet joint cysts in a 78-year-old man who had been treated with decompression and placement of a coflex device (Paradigm Spine) at L3-L4 and L4-L5. Preoperative imaging clearly demonstrated fluid in the facet joints without cysts. He underwent standard surgical treatment, but developed symptomatic facet joint cysts at 4 months postoperatively. The patient was treated with a revision decompression and replacement of the devices; there were no issues at the 32-month follow-up.

CONCLUSION

While the coflex device has possible long-term biomechanical advantages, vigilance with adherence to appropriate decompression surgical technique is necessary.

Biomechanical evaluation of a novel pedicle screw-based interspinous spacer: A finite element analysis

Interspinous spacers have been designed to provide a minimally invasive surgical technique for patients with lumbar spinal stenosis or foraminal stenosis. A novel pedicle screw-based interspinous spacer has been developed in this study, and the aim of this finite element experiment was to investigate the biomechanical differences between the pedicle screw-based interspinous spacer (M-rod system) and the typical interspinous spacer (Coflex-F™). A validated finite element model of an intact lumbar spine was used to analyze the insertions of the Coflex-F™, titanium alloy M-rod (M-Ti), and polyetheretherketone M-rod (M-PEEK), independently. The range of motion (ROM) between each vertebrae, stiffness of the implanted level, the peak stress at the intervertebral discs, and the contact forces on spinous process were analyzed. Of all three devices, the Coflex-F™ provided the largest restrictions in extension, flexion and lateral bending. For intervertebral disc, the peak stress at the implanted segment decreased by 81% in the Coflex-F™, 60.2% in the M-Ti and 46.7% in the M-PEEK when compared to the intact model. For the adjacent segments, while the Coflex-F™ caused considerable increases in the ROM and disc stress, the M-PEEK only had small changes.

The physical and psychological impact of neurogenic claudication: the patients' perspectives

BACKGROUND

The patient perspective regarding the impact of neurogenic claudication (NC) has not been well studied. The objectives of this study were to determine what is most bothersome among patients with NC and how it impacts their lives and expectations with surgical and non-surgical treatment.

METHODS

Semi-structured telephone interviews were conducted, audio recorded and transcribed verbatim. A thematic analysis categorized key findings based on relative importance and impact on participants.

RESULTS

Twenty-eight individuals participated in this study. Participants were most bothered by the pain of NC, which dramatically impacted their lives. Inability to walk was the dominant functional limitation and this impacted the ability to engage in recreational and social activities. The most surprising finding was how frequently participants reported significant emotional effects of NC.

CONCLUSIONS

From a patients' perspective NC has a significant multidimensional effects with pain, limited walking ability and emotional effects being most impactful to their lives.

Interspinous process devices(IPD) alone versus decompression surgery for lumbar spinal stenosis(LSS): A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

and purpose: Interspinous process devices (IPD) were widely used for the treatment of lumbar spinal stenosis (LSS). However, whether IPD was superior to bony decompression was still debated. We aimed to compare the clinical outcomes of IPD to bony decompression for LSS.

METHODS

PubMed, Cochrane library, Cochrane Central Register of Controlled Trials (CCTR), Ovid Medline, China national knowledge internet database, Wan Fang database were searched in August.8th.2016. Studies were identified using selection criteria and analysed was performed with Review Manager Version 5.3.

RESULTS

Four RCTs (seven articles) were included, with 200 patients in the interspinous process devices (IPD) group and 200 patients in bony decompression (DP) group. There was no significant difference in hospital stay time (P = 0.36), VAS leg pain scores (P = 0.83), and complication rates (P = 0.20) for IPD alone versus bony decompression. However, IPD alone showed higher VAS low back pain scores (P = 0.03) and reoperation rates (P < 0.0001) between the two therapy groups. Two studies' results showed the IPD group had lower cost-effectiveness.

CONCLUSIONS

Although patients who received IPD may obtain several benefits in the short term, it was associated with higher costs, reoperation rates. Both IPD and bony decompression were acceptable strategies for LSS, but the risks, indications, and costs of IPD should be carefully taken into account before surgery.

Surgical options for lumbar spinal stenosis

BACKGROUND

Hospital charges for lumbar spinal stenosis have increased significantly worldwide in recent times, with great variation in the costs and rates of different surgical procedures. There have also been significant increases in the rate of complex fusion and the use of spinal spacer implants compared to that of traditional decompression surgery, even though the former is known to incur costs up to three times higher. Moreover, the superiority of these new surgical procedures over traditional decompression surgery is still unclear.

OBJECTIVES

To determine the efficacy of surgery in the management of patients with symptomatic lumbar spinal stenosis and the comparative effectiveness between commonly performed surgical techniques to treat this condition on patient-related outcomes. We also aimed to investigate the safety of these surgical interventions by including perioperative surgical data and reoperation rates.

SEARCH METHODS

Review authors performed electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, AMED, Web of Science, LILACS and three trials registries from their inception to 16 June 2016. Authors also conducted citation tracking on the reference lists of included trials and relevant systematic reviews.

SELECTION CRITERIA

This review included only randomised controlled trials that investigated the efficacy and safety of surgery compared with no treatment, placebo or sham surgery, or with another surgical technique in patients with lumbar spinal stenosis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the studies for inclusion and performed the 'Risk of bias' assessment, using the Cochrane Back and Neck Review Group criteria. Reviewers also extracted demographics, surgery details, and types of outcomes to describe the characteristics of included studies. Primary outcomes were pain intensity, physical function or disability status, quality of life, and recovery. The secondary outcomes included measurements related to surgery, such as perioperative blood loss, operation time, length of hospital stay, reoperation rates, and costs. We grouped trials according to the types of surgical interventions being compared and categorised follow-up times as short-term when less than 12 months and long-term when 12 months or more. Pain and disability scores were converted to a common 0 to 100 scale. We calculated mean differences for continuous outcomes and relative risks for dichotomous outcomes. We pooled data using the random-effects model in Review Manager 5.3, and used the GRADE approach to assess the quality of the evidence.

MAIN RESULTS

We included a total of 24 randomised controlled trials (reported in 39 published research articles or abstracts) in this review. The trials included 2352 participants with lumbar spinal stenosis with symptoms of neurogenic claudication. None of the included trials compared surgery with no treatment, placebo or sham surgery. Therefore, all included studies compared two or more surgical techniques. We judged all trials to be at high risk of bias for the blinding of care provider domain, and most of the trials failed to adequately conceal the randomisation process, blind the participants or use intention-to-treat analysis. Five trials compared the effects of fusion in addition to decompression surgery. Our results showed no significant differences in pain relief at long-term (mean difference (MD) -0.29, 95% confidence interval (CI) -7.32 to 6.74). Similarly, we found no between-group differences in disability reduction in the long-term (MD 3.26, 95% CI -6.12 to 12.63). Participants who received decompression alone had significantly less perioperative blood loss (MD -0.52 L, 95% CI -0.70 L to -0.34 L) and required shorter operations (MD -107.94 minutes, 95% CI -161.65 minutes to -54.23 minutes) compared with those treated with decompression plus fusion, though we found no difference in the number of reoperations (risk ratio (RR) 1.25, 95% CI 0.81 to 1.92). Another three trials investigated the effects of interspinous process spacer devices compared with conventional bony decompression. These spacer devices resulted in similar reductions in pain (MD -0.55, 95% CI -8.08 to 6.99) and disability (MD 1.25, 95% CI -4.48 to 6.98). The spacer devices required longer operation time (MD 39.11 minutes, 95% CI 19.43 minutes to 58.78 minutes) and were associated with higher risk of reoperation (RR 3.95, 95% CI 2.12 to 7.37), but we found no difference in perioperative blood loss (MD 144.00 mL, 95% CI -209.74 mL to 497.74 mL). Two trials compared interspinous spacer devices with decompression plus fusion. Although we found no difference in pain relief (MD 5.35, 95% CI -1.18 to 11.88), the spacer devices revealed a small but significant effect in disability reduction (MD 5.72, 95% CI 1.28 to 10.15). They were also superior to decompression plus fusion in terms of operation time (MD 78.91 minutes, 95% CI 30.16 minutes to 127.65 minutes) and perioperative blood loss (MD 238.90 mL, 95% CI 182.66 mL to 295.14 mL), however, there was no difference in rate of reoperation (RR 0.70, 95% CI 0.32 to 1.51). Overall there were no differences for the primary or secondary outcomes when different types of surgical decompression techniques were compared among each other. The quality of evidence varied from 'very low quality' to 'high quality'.

AUTHORS' CONCLUSIONS

The results of this Cochrane review show a paucity of evidence on the efficacy of surgery for lumbar spinal stenosis, as to date no trials have compared surgery with no treatment, placebo or sham surgery. Placebo-controlled trials in surgery are feasible and needed in the field of lumbar spinal stenosis. Our results demonstrate that at present, decompression plus fusion and interspinous process spacers have not been shown to be superior to conventional decompression alone. More methodologically rigorous studies are needed in this field to confirm our results.

Interspinous process devices versus standard conventional surgical decompression for lumbar spinal stenosis: cost-utility analysis

BACKGROUND CONTEXT

In the 1980s, a new implant was developed to treat patients with intermittent neurogenic claudication caused by lumbar spinal stenosis (LSS). This implant is now widely used.

PURPOSE

The objective of this study is to determine whether a favorable cost-effectiveness for interspinous process devices (IPDs) compared with conventional bony decompression is attained.

STUDY DESIGN/SETTING

Cost-utility analysis was performed alongside a double-blind randomized controlled trial. Five neurosurgical centers (including one academic and four secondary level care centers) included participants for this study.

PATIENT SAMPLE

One hundred fifty-nine patients with LSS were treated with the implantation of IPD and with bony decompression. Eighty participants received an IPD, and seventy-nine participants underwent spinal bony decompression.

OUTCOME MEASURES

Outcome measures were quality-adjusted life-years (QALYs) and societal costs in the first year (estimated per quarter), estimated from patient-reported utilities (US and The Netherlands EuroQol 5D [EQ-5D] and EuroQol visual analog scale) and diaries on costs (health-care costs, patient costs, and productivity costs).

METHODS

All analyses followed the intention-to-treat principle. Given the statistical uncertainty of differences between costs and QALYs, cost-effectiveness acceptability curves graph the probability that a strategy is cost effective, as a function of willingness to pay. Paradigm Spine funded this trial but did not have any part in data analysis or the design and preparation of this article.

RESULTS

According to the EQ-5D, the valuation of quality of life after IPD and decompression was not different. Mean utilities during all four quarters were, not significantly, less favorable after IPD according to the EQ-5D with a decrease in QALYs according to the US EQ-5D of 0.024 (95% confidence interval, -0.031 to 0.079). From a health-care perspective, the costs of IPD treatment were higher (difference €3,030 per patient, 95% confidence interval, €561-€5,498). This significant difference is mainly because of additional cost of implants of €2,350 apiece. From a societal perspective, a nonsignificant difference of €2,762 (95% confidence interval, -€1,572 to €7,095) in favor of conventional bony decompression was found.

CONCLUSIONS

Implantation of IPD as indirect decompressing device is highly unlikely to be cost effective compared with bony decompression for patients with intermittent neurogenic claudication caused by LSS.

TRIAL REGISTRATION

Dutch Trial Register Number: NTR1307.

Interspinous spacers versus posterior lumbar interbody fusion for degenerative lumbar spinal diseases: a meta-analysis of prospective studies

PURPOSE

Our aim is to evaluate the safety and effectiveness of interspinous spacers versus posterior lumbar interbody fusion (PLIF) for degenerative lumbar spinal diseases.

METHODS

A comprehensive literature search was performed using PubMed, Web of Science and Cochrane Library through September 2015. Included studies were performed according to eligibility criteria. Data of complication rate, post-operative back visual analogue scale (VAS) score, Oswestry Disability Index (ODI) score, estimated blood loss (EBL), operative time, length of hospital stay (LOS), range of motion (ROM) at the surgical, proximal and distal segments were extracted and analyzed.

RESULTS

Ten studies were selected from 177 citations. The pooled data demonstrated the interspinous spacers group had a lower estimated blood loss (weighted mean difference [WMD]: -175.66 ml; 95 % confidence interval [CI], -241.03 to -110.30; p < 0.00001), shorter operative time (WMD: -55.47 min; 95%CI, -74.29 to -36.65; p < 0.00001), larger range of motion (ROM) at the surgical segment (WMD: 3.97 degree; 95%CI, -3.24 to -1.91; p < 0.00001) and more limited ROM at the proximal segment (WMD: -2.58 degree; 95%CI, 2.48 to 5.47; p < 0.00001) after operation. Post-operative back VAS score, ODI score, length of hospital stay, complication rate and ROM at the distal segment showed no difference between the two groups.

CONCLUSIONS

Our meta-analysis suggested that interspinous spacers appear to be a safe and effective alternative to PLIF for selective patients with degenerative lumbar spinal diseases. However, more randomized controlled trials (RCT) are still needed to further confirm our results.

Degenerative lumbar spinal stenosis treatment with Aperius™ PerCLID™ system and Falena® interspinous spacers: 1-year follow-up of clinical outcome and quality of life

PURPOSE

Evaluation of the efficacy of the Falena(®) and Aperius™ PerCLID™ interspinous devices in the treatment of degenerative lumbar spinal stenosis with neurogenic intermittent claudication refractory to conservative treatment.

MATERIALS AND METHODS

We retrospectively analyzed data from 24 patients (20 male and 4 female patients; 61 ± 7 years old), treated with an implantation of the AperiusTM PerCLID™ system, and from 35 patients (29 male and 6 female patients; 65 ± 9 years old) treated with the Falena(®) interspinous device.Patient pain intensity was evaluated by a 10-point visual analog scale (VAS), with a score (ranging from 0 = no pain to 10 = unbearable pain) that was collected before the procedure, at baseline; and at months 1, 6 and 12 after the interventional procedure. The assessment of quality of life (QOL) impairment was evaluated by the Oswestry Disability Index (ODI) questionnaire, which was administered beforehand at baseline; and at months 1, 6 and 12 after the interventional procedure. The vertebral canal area was measured by magnetic resonance imaging (MRI) scans before the treatment and at the one-year follow-up.

RESULTS

All patients completed the study with no complications. Both the Falena group and Aperius group of surgery patients showed a statistically significant reduction of their VAS and ODI scores at the 6- and 12-month follow-up (p < 0.0001). A statistically significant increase in the vertebral canal area was observed both in the group that received Falena (p < 0.0001) and in the group that received Aperius (p = 0.0003). At the 1-year follow-up, we observed that there was a higher increase of vertebral canal area in those patients whom were treated with the Falena device (p < 0.001).

CONCLUSIONS

The implantation of Falena(®) and Aperius™ PerCLID™ interspinous devices is an effective and safe procedure, in the medium term.

Efficacy and Safety of Mechanical Thrombectomy in Treating Acute Ischemic Stroke: A Meta Analysis

OBJECTIVES

Mechanical thrombectomy (MT) is a promising treatment for acute ischemic stroke (AIS). But the results of completed trials were contradictory. Hence, we performed a meta-analysis to evaluate the efficacy and safety of MT in treating AIS.

METHODS

Literatures were searched in the databases including Pubmed, Cochrane Library, Web of Science and Ovid-SP. The bias and quality of publications with randomized controlled trials (RCTs) were assessed with the Cochrane collaboration's tool for assessing risk of bias.

RESULTS

Totally 16 publications matched the inclusion criteria, including seven independent RCTs and 2043 AIS patients. The results showed that the recanalization rate and the modified Rankin score of 0-2 at 90 days after treatment were better in MT combining standard care group, but the mortality had no significant difference, even the incidence of intracerebral hemorrhage during follow-up period was worse, as compared with standard care group.

CONCLUSION

MT combining standard care would be an effective and promising treatment for AIS patients according to the present study.

Aperius interspinous device for degenerative lumbar spinal stenosis: a review

With an aging population, degenerative lumbar spinal stenosis (DLSS) leading to neurogenic intermittent claudication (NIC) is a growing problem. For patients suffering from this condition, interspinous process distraction devices (IPDs) offer an effective and cheap alternative to conservative or decompressive surgery. Aperius is one such device that has been gaining popularity for its percutaneous insertion under local anesthetic, short operative time, and low risk of complications. The main objective of this review was to carry out a comprehensive search of the literature to evaluate the effectiveness and potential complications of Aperius. A database search, including PubMed, Clinical trials.gov, Cochrane (CENTRAL), MEDLINE, CINAHL, EMBASE, and Scopus, was carried out to identify relevant articles written in English reporting on complications with a minimum 12-month follow-up. The literature search resulted in six eligible studies; two nonrandomized comparative and four prospective case series were available. The analysis revealed that in total, 433 patients underwent treatment with Aperius, with all studies demonstrating an improvement in outcome measures. The average follow-up was 17 months with an overall complication rate of 10.62%. Overall, the quality of evidence is low, suggesting that currently, the evidence is not compelling and further prospective randomized trials including cost-effectiveness studies are required.

Arguments for the choice of surgical treatments in patients with lumbar spinal stenosis - a systematic appraisal of randomized controlled trials

BACKGROUND

Lumbar spinal stenosis is the most common reason for spinal surgery in elderly patients. However, the surgical management of spinal stenosis is controversial. The aim of this review was to list aspects a surgeon considers when choosing a specific type of treatment.

METHODS

Appraisal of arguments reported in randomized controlled trials (RCTs) included in systematic reviews published or indexed in the Cochrane library studying surgical treatments in patients with spinal stenosis.

RESULTS

Eight out of nine RCTs listed arguments for the choice of their treatments under investigation. The argument for decompression alone was the high success rate, the argument against was a potential increase in vertebral instability. The argument for decompression and fusion without instrumentation was that it is a well-established technique with a high fusion success rate, the argument against it was that the indication for fusion in spinal stenosis has remained unclear. The argument for decompression and fusion with instrumentation was an increased fusion rate compared to decompression and fusion without instrumentation, the argument against this was that the invasive procedure is associated with more complications.

CONCLUSIONS

The main argument identified in this appraisal for and against decompression alone in patient with lumbar spinal stenosis was whether or not instability should be treated with (instrumented) fusion procedures. However, there is disagreement on how instability should be defined. In a first step it is important that researchers and clinicians agree on definitions for important key concepts such as instability and reoperations.

Grade 1 spondylolisthesis and interspinous device placement: removal in six patients and analysis of current data

Background:

In the treatment of patients with Grade 1 spondylolisthesis, the use of interspinous devices has been controversial for nearly a decade. Several authors have suggested that Grade 1 spondylolisthesis be considered a contraindication for interspinous device placement.

Methods:

We removed interspinous devices in six symptomatic Grade 1 spondylolisthesis patients and analyzed pertinent literature.

Results:

All six patients reported an improvement in symptoms following device removal and subsequent instrumented fusion. One patient who had not been able to walk due to pain regained the ability to walk. Several articles were identified related to spondylolisthesis and interspinous devices.

Conclusions:

Regarding patients receiving interspinous devices for symptomatic lumbar spinal stenosis, several high-quality studies have failed to demonstrate a statistical difference in outcomes between patients with or without Grade 1 spondylolisthesis. Nevertheless, surgeons should have a high degree of suspicion when considering use of interspinous devices in this patient population.

Biomechanical study of dynamic changes in L4-L5 foramen surface area in flexion and extension after implantation of four interspinous process devices

BACKGROUND

Lumbar spinal stenosis is a major public health issue. Interspinous devices implanted using minimally invasive techniques may constitute an alternative to the reference standard of bony decompression with or without intervertebral fusion. However, their indications remain unclear, due to a paucity of clinical and biomechanical data. Our objective was to evaluate the effects of four interspinous process devices implanted at L4-L5 on the intervertebral foramen surface areas at the treated and adjacent levels, in flexion and in extension.

MATERIALS AND METHOD

Six fresh frozen human cadaver lumbar spines (L2-sacrum) were tested on a dedicated spinal loading frame, in flexion and extension, from 0 to 10 N·m, after preparation and marking of the L3-L4, L4-L5, and L5-S1 foramina. Stereoscopic 3D images were acquired at baseline then after implantation at L4-L5 of each of the four devices (Inspace(®), Synthes; X-Stop(®), Medtronic; Wallis(®), Zimmer; and Diam(®), Medtronic). The surface areas of the three foramina of interest were computed.

RESULTS

All four devices significantly opened the L4-L5 foramen in extension. The effects in flexion separated the devices into two categories. With the two devices characterized by fixation in the spinous processes (Wallis(®) and Diam(®)), the L4-L5 foramen opened only in extension; whereas with the other two devices (X-Stop(®) and Inspace(®)), the L4-L5 foramen opened not only in extension, but also in flexion and in the neutral position. None of the devices implanted at L4-L5 modified the size of the L3-L4 foramen. X-Stop(®) and Diam(®) closed the L5-S1 foramen in extension, whereas the other two devices had no effect at this level.

CONCLUSION

Our results demonstrate that interspinous process devices modify the surface area of the interspinous foramina in vitro. Clinical studies are needed to clarify patient selection criteria for interspinous process device implantation.

LEVEL OF EVIDENCE

Level IV. Investigating an orthopaedic device.

Effectiveness of surgery for lumbar spinal stenosis: a systematic review and meta-analysis

Background

The management of spinal stenosis by surgery has increased rapidly in the past two decades, however, there is still controversy regarding the efficacy of surgery for this condition. Our aim was to investigate the efficacy and comparative effectiveness of surgery in the management of patients with lumbar spinal stenosis.

Methods

Electronic searches were performed on MEDLINE, EMBASE, AMED, CINAHL, Web of Science, LILACS and Cochrane Library from inception to November 2014. Hand searches were conducted on included articles and relevant reviews. We included randomised controlled trials evaluating surgery compared to no treatment, placebo/sham, or to another surgical technique in patients with lumbar spinal stenosis. Primary outcome measures were pain, disability, recovery and quality of life. The PEDro scale was used for risk of bias assessment. Data were pooled with a random-effects model, and the GRADE approach was used to summarise conclusions.

Results

Nineteen published reports (17 trials) were included. No trials were identified comparing surgery to no treatment or placebo/sham. Pooling revealed that decompression plus fusion is not superior to decompression alone for pain (mean difference –3.7, 95% confidence interval –15.6 to 8.1), disability (mean difference 9.8, 95% confidence interval –9.4 to 28.9), or walking ability (risk ratio 0.9, 95% confidence interval 0.4 to 1.9). Interspinous process spacer devices are slightly more effective than decompression plus fusion for disability (mean difference 5.7, 95% confidence interval 1.3 to 10.0), but they resulted in significantly higher reoperation rates when compared to decompression alone (28% v 7%, P < 0.001). There are no differences in the effectiveness between other surgical techniques for our main outcomes.

Conclusions

The relative efficacy of various surgical options for treatment of spinal stenosis remains uncertain. Decompression plus fusion is not more effective than decompression alone. Interspinous process spacer devices result in higher reoperation rates than bony decompression.

Management of lumbar spinal stenosis: a survey among Dutch spine surgeons

BACKGROUND

Various surgical and non-surgical treatments for lumbar spinal stenosis (LSS) are widely adopted in clinical practice, but high quality randomised controlled trials to support these are often lacking, especially in terms of their relative benefit and risk compared with other treatment options. Therefore, an evaluation of agreement among clinicians regarding the indications and the choice for particular treatments seems appropriate.

METHODS

One hundred and six Dutch neurosurgeons and orthopaedic spine surgeons completed a questionnaire, which evaluated treatment options for LSS and expectations regarding the effectiveness of surgical and non-surgical treatments.

RESULTS

Responders accounted for 6,971 decompression operations and 831 spinal fusion procedures for LSS annually. Typical neurogenic claudication, severe pain/disability, and a pronounced constriction of the spinal canal were considered the most important indications for surgical treatment by the majority of responders. Non-surgical treatment was generally regarded as ineffective and believed to be less effective than surgical treatment. Interlaminar decompression was the preferred technique by 68% of neurosurgeons and 52% orthopaedic surgeons for the treatment of LSS. Concomitant fusion was applied in 12% of all surgery for LSS. Most surgeons considered spondylolisthesis as an indication and spinal instability as a definite indication for additional fusion.

CONCLUSIONS

The current survey demonstrates a wide variety of preferred treatments of symptomatic LSS by Dutch spine surgeons. To minimise variety, national and international protocols based on high-quality randomised controlled trials and systematic reviews are necessary to give surgeons more tools to support everyday decision-making.

Comparison of one versus two cages in lumbar interbody fusion for degenerative lumbar spinal disease: a meta-analysis

OBJECTIVE

To systematically compare the fusion rate and safety of lumbar interbody fusion using one cage versus two cages for the treatment of degenerative lumbar spinal diseases.

METHODS

All randomized controlled trials (RCTs) and comparative observational studies written in English comparing the outcome of lumbar interbody fusion using one or two cages in patients with degenerative lumbar spinal diseases were identified by a comprehensive search of PubMed Central, MEDLINE, EMBASE, BIOSIS and the Cochrane Central Registry of Controlled Trials. An exhaustive electronic search up to July 2013. The quality of the methodology was assessed and relevant data retrieved independently by two reviewers, after which the resultant data were subjected to meta-analysis. All meta-analyses were performed using Review Manager 5.0, which is recommended and provided by the Cochrane Collaboration.

RESULTS

Our systematic search yielded 745 studies from the selected databases. After duplicate studies had been identified and the titles and abstracts screened, 736 studies were excluded because they were irrelevant to our topic. The full texts of the remaining nine potentially relevant references were comprehensively evaluated and four excluded for the following reasons: two studies involved co-interventions and the other two lacked control groups. Two relevant RCTs and three comparative observational studies involving 384 patients and 501 spinal segments with at least one year follow-up were identified. Analysis of the pooled data demonstrated no significant difference in fusion rate between the one-cage and two-cage groups. However, intraoperative blood loss and operating time were less and the complications rate lower in the one-cage group.

CONCLUSION

In patients with degenerative lumbar spinal diseases, lumbar interbody fusion using one cage has an equal fusion rate and is safer compared with using two cages. However, because this meta-analysis had some limitations, more high quality RCTs are needed to strengthen the evidence.

Comparison of the efficacy and safety between interspinous process distraction device and open decompression surgery in treating lumbar spinal stenosis: a meta analysis

OBJECTIVES

The present study performed a meta-analysis to evaluate the efficacy and safety of interspinous process distraction device (IPD) compared with open decompression surgery (ODS) in treating lumbar spinal stenosis.

METHODS

Literatures were searched in the databases including Cochrane Library, Pubmed, OvidSP, Sciencedirect, Web of Science, and Springerlin. Published reviews were checked to track missed original research papers. The quality and bias of publications with randomized controlled trial were evaluated using the tool for assessing risk of bias in the Cochrane handbook. The quality and bias of publications with cohort trial were evaluated using the Newcastle-Ottawa Scale. The grades of literatures were evaluated with the guidelines of Grading of Recommendations Assessment Development and Evaluation (GRADE).

RESULTS

Totally, 21 publications matched the inclusion criteria, including 20 different clinical trials and 54,138 patients. The results indicated that there was no significant difference in improvement rate, Oswestry disability index questionnaire (ODI) score, and visual analog scale (VAS) score of back pain or leg pain between IPD group and ODS group. The postoperation complication rate, perioperation blood loss, hospitalization time, and operation time were lower/shorter in IPD group than ODS group. However, the reoperation rate in IPD group was higher than ODS group.

CONCLUSION

The results indicated that IPD has better effects and less complication than ODS. However, because of the higher reoperation rate in IPD than ODS, we failed to conclude that IPD could replace ODS as golden standard but may be a viable alternative in treating lumbar spinal stenosis.

One-year follow-up of a series of 100 patients treated for lumbar spinal canal stenosis by means of HeliFix interspinous process decompression device

PURPOSE

New interspinous process decompression devices (IPDs) provide an alternative to conservative treatment and decompressive surgery for patients with neurogenic intermittent claudication (NIC) due to degenerative lumbar spinal stenosis (DLSS). HeliFix is a minimally invasive IPD that can be implanted percutaneously. This is a preliminary evaluation of safety and effectiveness of this IPD up to 12 months after implantation.

METHODS

After percutaneous implantation in 100 patients with NIC due to DLSS, data on symptoms, quality of life, pain, and use of pain medication were obtained for up to 12 months.

RESULTS

Early symptoms and physical function improvements were maintained for up to 12 months. Leg, buttock/groin, and back pain were eased throughout, and the use and strength of related pain medication were reduced. Devices were removed from 2% of patients due to lack of effectiveness.

CONCLUSIONS

Overall, in a period of up to 12-month follow-up, the safety and effectiveness of the HeliFix offered a minimally invasive option for the relief of NIC complaints in a high proportion of patients. Further studies are undertaken in order to provide insight on outcomes and effectiveness compared to other decompression methods and to develop guidance on optimal patient selection.

What interventions improve walking ability in neurogenic claudication with lumbar spinal stenosis? A systematic review

PURPOSE

To investigate what interventions can improve walking ability in neurogenic claudication with lumbar spinal stenosis.

METHODS

We searched CENTRAL, Medline, EMBASE, CINAHL and ICL databases up to June 2012. Only randomized controlled trials published in English and measuring walking ability were included. Data extraction, risk of bias assessment, and quality of the evidence evaluation were performed using methods of the Cochrane Back Review Group.

RESULTS

We accepted 18 studies with 1,220 participants. There is very low quality evidence that calcitonin is no better than placebo or paracetamol regardless of mode of administration. There is low quality evidence that prostaglandins, and very low quality evidence that gabapentin or methylcobalamin, improves walking distance. There is low and very low quality evidence that physical therapy was no better in improving walking ability compared to no treatment, oral diclofenac plus home exercises, or combined manual therapy and exercise. There is very low quality evidence that epidural injections improve walking distance up to 2 weeks compared to placebo. There is low- and very low-quality evidence that various direct decompression surgical techniques show similar significant improvements in walking ability. There is low quality evidence that direct decompression is no better than non-operative treatment in improving walking ability. There is very low quality evidence that indirect decompression improves walking ability compared to non-operative treatment.

CONCLUSIONS

Current evidence for surgical and non-surgical treatment to improve walking ability is of low and very low quality and thus prohibits recommendations to guide clinical practice.

Incidence of heterotopic ossification after implantation of interspinous process devices

OBJECT

This study aimed to investigate the incidence rate of heterotopic ossification (HO) after implantation of Coflex interspinous devices. Possible risk factors associated with HO were evaluated.

METHODS

The authors retrospectively analyzed patients who had undergone single-level (L4-5) implantation of a Coflex device for the treatment of lumbar spinal stenosis. Patient data recorded were age, sex, height, weight, body mass index, smoking habits, and surgical time. Heterotopic ossification was identified through lumbar anteroposterior and lateral view radiographs. The authors developed a simple classification for defining HO and compared HO-positive and HO-negative cases to identify possible risk factors.

RESULTS

Among 32 patients with follow-up times of 24-57 months, HO was detectable in 26 (81.2%). Among these 26 patients, HO was in the lateral space of the spinous process but not in the interspinous space in 8, HO was in the interspinous space but did not bridge the adjacent spinous process in 16, and interspinous fusion occurred at the level of the device in 2. Occurrence of HO was not associated with patient age, sex, height, weight, body mass index, smoking habits, or surgical time.

CONCLUSIONS

A high incidence of HO has been detected after implantation of Coflex devices. Clinicians should be aware of this possible outcome, and more studies should be conducted to clarify the clinical effects of HO.

The effect of design parameters of interspinous implants on kinematics and load bearing: an in vitro study

INTRODUCTION

A number of concepts with controversy approaches are currently discussed for interspinous stabilization (IPS). However, comparative biomechanical studies among the different systems are rare. Nevertheless, it remains unclear which biomechanical characteristics are influenced by different design features of these implants, such as implant stiffness or an additional tension band. Therefore, the aim of the present study was to compare different interspinous implants to investigate the biomechanical impact of IPS implant design on intersegmental kinematics, such as range of motion, neutral zone, center of rotation (COR), as well as load transfer like intradiscal pressure (IDP), to gain additional experience for clinical indications and limitations.

MATERIAL AND METHOD

Twelve human lumbar spine specimens were tested in a spine loading apparatus. In vitro flexibility testing was performed by applying pure bending moments of 7.5 Nm without and with additional preload of 400 N in the three principal motion planes. Four interspinous implants, Coflex "COF" (Paradigm Spine, Germany), Wallis "WAL" (Abbott Laboratories, France), DIAM "DIA" (Sofamor Danek, France) and InterActiv (Aesculap AG, Germany) with two treatment options (without dorsal tensioning "IAO" and with dorsal tensioning "IAM") were consecutively tested in comparison to the native situation "NAT" and to a defect situation "DEF" of the functional spinal unit. The tested IPS devices are comprised of a compression stiffness range of 133 to 1,674 N/mm and a tensile stiffness range of 0-39 N/mm. Range of motion, neutral zone, center of rotation and intradiscal pressure were analyzed for all instrumentation steps and load cases.

CONCLUSION

For the IPS, we found a correlation between compression stiffness and stabilization in extension. Here, the system with the lowest stiffness, DIA, displayed nearly no stabilization of the treated segment, whereas the system with the highest stiffness, WAL and COF, was most pronounced. This applies also for the correlation between device stiffness and IDP. In flexion only the degree of stabilization is in correlation with the tensile stiffness, whereas the IDP stays constant and is not affected by the different tensile stiffness. IPS is not able to stabilize in the frontal and transversal plane. Furthermore IPS does not substantially alter the location of the COR.

Interspinous process device versus standard conventional surgical decompression for lumbar spinal stenosis: randomized controlled trial

OBJECTIVE

To assess whether interspinous process device implantation is more effective in the short term than conventional surgical decompression for patients with intermittent neurogenic claudication due to lumbar spinal stenosis.

DESIGN

Randomized controlled trial.

SETTING

Five neurosurgical centers (including one academic and four secondary level care centers) in the Netherlands.

PARTICIPANTS

203 participants were referred to the Leiden-The Hague Spine Prognostic Study Group between October 2008 and September 2011; 159 participants with intermittent neurogenic claudication due to lumbar spinal stenosis at one or two levels with an indication for surgery were randomized.

INTERVENTIONS

80 participants received an interspinous process device and 79 participants underwent spinal bony decompression.

MAIN OUTCOME MEASURES

The primary outcome at short term (eight weeks) and long term (one year) follow-up was the Zurich Claudication Questionnaire score. Repeated measurements were made to compare outcomes over time.

RESULTS

At eight weeks, the success rate according to the Zurich Claudication Questionnaire for the interspinous process device group (63%, 95% confidence interval 51% to 73%) was not superior to that for standard bony decompression (72%, 60% to 81%). No differences in disability (Zurich Claudication Questionnaire; P=0.44) or other outcomes were observed between groups during the first year. The repeat surgery rate in the interspinous implant group was substantially higher (n=21; 29%) than that in the conventional group (n=6; 8%) in the early post-surgical period (P<0.001).

CONCLUSIONS

This double blinded study could not confirm the hypothesized short term advantage of interspinous process device over conventional "simple" decompression and even showed a fairly high reoperation rate after interspinous process device implantation.

TRIAL REGISTRATION

Dutch Trial Register NTR1307.

Evidence for surgery in degenerative lumbar spine disorders

We aimed to evaluate the available evidence on the effectiveness of surgical interventions for a number of conditions resulting in low back pain (LBP) or spine-related irradiating leg pain. We searched the Cochrane databases and PubMed up to June 2013. We included systematic reviews and randomised controlled trials (RCTs) on degenerative disc disease (DDD), herniated disc, spondylolisthesis and spinal stenosis due to degenerative osteoarthritis. We included comparisons between surgery and conservative care and between different techniques. The quality of the systematic reviews was evaluated using assessment of multiple systematic reviews (AMSTAR). Twenty systematic reviews were included which covered the following diagnoses: disc herniation (n = 9), spondylolisthesis (n = 2), spinal stenosis (n = 3), DDD (n = 4) and combinations (n = 2). For most of the comparisons, no significant and/or clinically relevant differences between interventions were identified. In general, surgery is only indicated for relief of leg pain in clear indications such as disc herniation, spondylolisthesis or spinal stenosis.

Motion characteristics of the lumbar spinous processes with degenerative disc disease and degenerative spondylolisthesis

OBJECTIVE

Recently, interspinous process devices have attracted much attention since they can be implanted between the lumbar spinous processes (LSP) of patients with degenerative disc disease (DDD) and degenerative spondylolisthesis (DLS) using a minimally invasive manner. However, the motion characters of the LSP in the DLS and DDD patients have not been reported. This study is aimed at investigating the kinematics of the lumbar spinous processes in patients with DLS and DDD.

METHODS

Ten patients with DDD at L4-S1 and ten patients with DLS at L4-L5 were studied. The positions of the vertebrae (L2-L5) at supine, standing, 45° trunk flexion, and maximal extension positions were determined using MRI-based models and dual fluoroscopic images. The shortest ISP distances were measured and compared with those of healthy subjects that have been previously reported.

RESULTS

The shortest distance of the interspinous processes (ISP) gradually decreased from healthy subjects to DDD and to DLS patients when measured in the supine, standing, and extension positions. During supine-standing and flexion-extension activities, the changes in the shortest ISP distances in DDD patients were 2 ± 1.2 and 4.8 ± 2.1 mm at L4-L5; in DLS patients they were 0.5 ± 0.4 and 2.8 ± 1.7 mm at L4-L5, respectively. The range of motion is increased in DDD patients but decreased in DLS patients when compared with those of the healthy subjects. No significantly different changes were detected at L2-L3 and L3-L4 levels.

CONCLUSION

At the involved level, the hypermobility of the LSP was seen in DDD and hypomobility of the LSP in DLS patients. The data may be instrumental for improving ISP surgeries that are aimed at reducing post-operative complications such as bony fracture and device dislocations.

Complications in degenerative lumbar disease treated with a dynamic interspinous spacer (Coflex)

PURPOSE

The purpose of this study was to quantify the intra- and postoperative complications of an interspinous process device (Coflex) in managing degenerative lumbar diseases and to investigate corresponding therapeutic strategies.

METHODS

Between January 2008 and December 2012, we retrospectively analysed a total of 131 patients who underwent decompressive surgery along with the Coflex system for the treatment of degenerative lumbar diseases. The related complications were reported, and appropriate measures were taken. Clinical outcomes and radiological data were collected and analysed, and clinical outcomes were evaluated with paired-samples T test.

RESULTS

Related complications occurred in 11 patients. Among them, six cases were found with surgical technique-related complications, including device-related complications in three cases: spinal process fracture (n = 1), Coflex loosening (n = 1), fixed-wing breakage (n = 1), dura mater tear in two cases and superficial wound infection in one case. All of them received corresponding conservative treatment and obtained a good result. The other five cases had non-device-related complications and required additional spinal surgery. The conservative therapy group had apparent improvement of VAS score and ODI, and remained well to final follow-up (P < 0.05). The second operation group also improved postoperatively (each P < 0.05).

CONCLUSION

The Coflex dynamic interspinous process device shows a low complication and re-operation rate. Standard operation and strict follow-up observation can effectively avoid surgical technique-related complications. The key points to ensure surgical effect and to reduce non-device-related complications are mastering surgical indications and thorough intra-operative decompression.

The evidence on surgical interventions for low back disorders, an overview of systematic reviews

PURPOSE

Many systematic reviews have been published on surgical interventions for low back disorders. The objective of this overview was to evaluate the available evidence from systematic reviews on the effectiveness of surgical interventions for disc herniation, spondylolisthesis, stenosis, and degenerative disc disease (DDD). An earlier version of this review was published in 2006 and since then, many new, better quality reviews have been published.

METHODS

A comprehensive search was performed in the Cochrane database of systematic reviews (CDSR), database of reviews of effectiveness (DARE) and Pubmed. Two reviewers independently performed the selection of studies, risk of bias assessment, and data extraction. Included are Cochrane reviews and non-Cochrane systematic reviews published in peer-reviewed journals. The following conditions were included: disc herniation, spondylolisthesis, and DDD with or without spinal stenosis. The following comparisons were evaluated: (1) surgery vs. conservative care, and (2) different surgical techniques compared to one another. The methodological quality of the systematic reviews was evaluated using AMSTAR. We report (pooled) analyses from the individual reviews.

RESULTS

Thirteen systematic reviews on surgical interventions for low back disorders were included for disc herniation (n = 6), spondylolisthesis (n = 2), spinal stenosis (n = 4), and DDD (n = 4). Nine (69 %) were of high quality. Five reviews provided a meta-analysis of which two showed a significant difference. For the treatment of spinal stenosis, intervertebral process devices showed more favorable results compared to conservative treatment on the Zurich Claudication Questionnaire [mean difference (MD) 23.2 95 % CI 18.5-27.8]. For degenerative spondylolisthesis, fusion showed more favorable results compared to decompression for a mixed aggregation of clinical outcome measures (RR 1.40 95 % CI 1.04-1.89) and fusion rate favored instrumented fusion over non-instrumented fusion (RR 1.37 95 % CI 1.07-1.75).

CONCLUSIONS

For most of the comparisons, the included reviews were not significant and/or clinically relevant differences between interventions were identified. Although the quality of the reviews was quite acceptable, the quality of the included studies was poor. Future studies are likely to influence our assessment of these interventions.

Percutaneous interspinous spacer versus open decompression: a 2-year follow-up of clinical outcome and quality of life

PURPOSE

Percutaneous interspinous stand-alone spacers offer a simple and effective technique to treat lumbar spinal stenosis with neurogenic claudication. Nonetheless, open decompressive surgery remains the standard of care. This study compares the effectiveness of both techniques and the validity of percutaneous interspinous spacer use.

METHODS

Forty-five patients were included in this open prospective non-randomized study, and treated either with percutaneous interspinous stand-alone spacers (Aperius(®)) or bilateral open microsurgical decompression at L3/4 or L4/5. Patient data, operative data, COMI, SF-36, PCS and MCS, ODI, and walking distance were collected 6 weeks, 3, 6, 9, 12, and 24 months post-surgery.

RESULTS

Group 1 (n = 12) underwent spacer implantation, group 2 (n = 33) open decompression. Five patients from group 1 required implant removal and open decompression during follow-up (FU); one patient was lost to FU. From group 2, seven patients were lost to FU. Remaining patients were assessed as above. After 2 years, back pain, leg pain, ODI, and quality of life improved significantly for group 2. Remaining group 1 patients (n = 6) reported worse results. Walking distance improved for both groups.

CONCLUSION

Decompression proved superior to percutaneous stand-alone spacer implantation in our two observational cohorts. Therapeutic failure was too high for interspinous spacers.

Histomorphometric and radiographical changes after lumbar implantation of the PEEK nonfusion interspinous device in the BB.4S rat model

STUDY DESIGN

An experimental animal study.

OBJECTIVE

To investigate histomorphometric and radiographical changes in the BB.4S rat model after PEEK (polyetheretherketone) nonfusion interspinous device implantation.

SUMMARY OF BACKGROUND DATA

Clinical effectiveness of the PEEK nonfusion spine implant Wallis (Abbott, Bordeaux, France; now Zimmer, Warsaw, IN) is well documented. However, there is a lack of evidence on the long-term effects of this implant on bone, in particular its influence on structural changes of bone elements of the lumbar spine.

METHODS

Twenty-four male BB.4S rats aged 11 weeks underwent surgery for implantation of a PEEK nonfusion interspinous device or for a sham procedure in 3 groups of 8 animals each: (1) implantation at level L4-L5; (2) implantation at level L5-L6; and (3) sham surgery. Eleven weeks postoperatively osteolyses at the implant-bone interface were measured via radiograph, bone mineral density of vertebral bodies was analyzed using osteodensitometry, and bone mineral content as well as resorption of the spinous processes were examined by histomorphometry. RESULTS.: Resorption of the spinous processes at the site of the interspinous implant was found in all treated segments. There was no significant difference in either bone density of vertebral bodies or histomorphometric structure of the spinous processes between adjacent vertebral bodies, between treated and untreated segments and between groups.

CONCLUSION

These findings indicate that resorption of spinous processes because of a result of implant loosening, inhibit the targeted load redistribution through the PEEK nonfusion interspinous device in the lumbar spinal segment of the rat. This leads to reduced long-term stability of the implant in the animal model. These results suggest that PEEK nonfusion interspinous devices like the Wallis implants may have time-limited effects and should only be used for specified indications.

Clinical evaluation of the preliminary safety and effectiveness of a minimally invasive interspinous process device APERIUS(®) in degenerative lumbar spinal stenosis with symptomatic neurogenic intermittent claudication

PURPOSE

New interspinous process decompression devices (IPDs) provide an alternative to conservative treatment and decompressive surgery for patients with neurogenic intermittent claudication (NIC) due to degenerative lumbar spinal stenosis (DLSS). APERIUS(®) is a minimally invasive IPD that can be implanted percutaneously. This multicentre prospective study was designed to make a preliminary evaluation of safety and effectiveness of this IPD up to 12 months post-implantation.

METHODS

After percutaneous implantation in 156 patients with NIC due to DLSS, data on symptoms, quality of life, pain, and use of pain medication were obtained for up to 12 months.

RESULTS

Early symptom and physical function improvements were maintained for up to 12 months, when 60 and 58 % of patients maintained an improvement higher than the Minimum Clinically Important Difference for Zurich Claudication Questionnaire (ZCQ) symptom severity and physical function, respectively. Leg, buttock/groin, and back pain were eased throughout, and the use and strength of related pain medication were reduced. Devices were removed from 9 % of patients due to complications or lack of effectiveness.

CONCLUSIONS

Overall, in a period of up to 12 months follow-up, the safety and effectiveness of the APERIUS(®) offered a minimally invasive option for the relief of NIC complaints in a high proportion of patients. Further studies are underway to provide insight on outcomes and effectiveness compared to other decompression methods, and to develop guidance on optimal patient selection.