A comparison of the clinical outcomes of decompression alone and fusion in elderly patients with two-level or more lumbar spinal stenosis

Long-term reoperation after decompression with versus without fusion among patients with degenerative lumbar spinal stenosis: a systematic review and meta-analysis

BACKGROUND

The debate over adding fusion after decompression in lumbar spinal stenosis patients without spondylolisthesis is due to the "absence of evidence" in its benefits, particularly in reoperation. However, this "absence of evidence" does not indicate "evidence of absence."

PURPOSE

To investigate the reoperation rates following the addition of fusion after decompression in patients with lumbar spinal stenosis without spondylolisthesis.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

We searched Medline, Embase, Web of Science, and Google Scholar databases on December 12, 2021, with an updated search conducted on April 06, 2023. Inclusion criteria were adult patients with lumbar spinal stenosis. Exclusions comprised cases of spondylolisthesis and instabilities. The occurrence of reoperation was summarized using odds ratios (OR), while other outcomes were presented as mean differences. We employed a Cox-based shared-frailty model with random effects for the time-to-event analysis of reoperation. Additionally, we used a 2-stage method to validate our estimates. Heterogeneity variance within the random-effects model was estimated using the Hartung-Knapp-Sidik-Jonkman method.

RESULTS

A total of 1973 studies were identified and screened, of which 48 met selection criteria, and 17 were included in the meta-analysis. Comparison between fusion and nonfusion groups in patients with lumbar stenosis and neurological claudication revealed no significant difference in reoperation rates (odds ratio: 1.13 [95% CI: 0.88 to 1.46]; 8016 participants; 14 studies; I2 = 0%). Bayesian analysis indicated an 8.9-fold likelihood of similar reoperation rates. Time-to-reoperation analysis revealed a 16.46 months delay in the fusion group, though not statistically significant (mean difference: 16.46 [95% CI: -3.13-36.04]; 83 participants; 3 studies; I2 = 46%). Consistently, ODI, back pain, and leg pain VAS showed no significant differences. The certainty of the evidence was low for odds of reoperation and leg pain VAS, and very low for the remaining outcomes.

CONCLUSION

In lumbar spinal stenosis patients without spondylolisthesis, the addition of fusion after decompression showed limited benefits in terms of reoperation rates, ODI, and leg pain.

Spondylolisthesis and Scoliosis Progression and Associated Revision Rates Following Bilateral Lumbar Spine Microscopic Decompression

Lumbar spine microscopic decompression (LSMD) is a common surgical procedure for decompressing neural elements. Although the optimal extent of decompression remains a critical consideration, limited evidence-based guidelines define the threshold for instrumented fusion to maintain biomechanical stability. Existing studies suggest that unilateral LSMD generally does not result in iatrogenic instability. However, the potential instability associated with bilateral segmental decompression (BLSMD) is less well-defined, particularly in patients with pre-existing degenerative lumbar scoliosis (SC) or spondylolisthesis (SL). This retrospective study included patients undergoing BLSMD without instrumented fusion. Pre-existing SC was defined as Cobb's angle ≥10° and SL as any anterior-posterior slip of operated level adjacent vertebral bodies. The primary outcome was new or progressive SC/SL measured on pre and postoperative radiographs. Secondary outcomes were revision rates, changes in Visual Analog Scores (bVAS/lVAS), and Oswestry Disability Index (ODI) scores, collected preoperatively and 1-2 years postoperatively. Baseline characteristics such as age, BMI, sex, and number of levels operated were also collected. A total of 31 patients were reviewed comprising 15 female and 16 male patients with a mean age of 61.4 years (21-78) and BMI of 26.5 (18-41). There were 14 one-level, 12 two-level, and 4 three-level BLSMD performed. Patients with pre-existing SC and SL had a 66% and 23% incidence of radiological progression, respectively, compared to 0% in patients without pre-existing deformity. Progression cases were associated with high reoperation rates (up to 75%) and seemed to have inferior clinical outcomes than those without progression. In patients undergoing BLSMD, pre-existing SC/SL is linked to a higher incidence of radiological progression and higher reoperation rates. For patients with SC/SL, careful consideration should be given to limiting decompression, potentially exploring fusion options, and implementing close postoperative radiographic monitoring.

Efficacy and Safety of Biportal Endoscopic Decompressive Laminectomy in Octogenarians With Severe Lumbar Spinal Stenosis

BACKGROUND

Lumbar spinal stenosis (LSS) is prevalent among octogenarians, causing significant pain and disability. Surgical intervention is often required because of the ineffectiveness of conservative treatments. This study investigates the efficacy and safety of biportal endoscopic decompressive laminectomy (BED) in octogenarians with severe LSS, evaluating its potential as a minimally invasive surgical option.

METHODS

This retrospective study included 107 patients aged 80 years or older who underwent BED for LSS between March 2017 and December 2022. Data were collected from electronic medical records, including demographic information, clinical outcomes, and surgical details. Patients with fractures, infectious spondylitis, herniated discs, and follow-up less than 12 months were excluded. Clinical outcomes were assessed using the visual analog scale, Oswestry Disability Index, European Quality of Life-5 Dimensions, and painDETECT at baseline and at 3, 6, and 12 months after surgery.

RESULTS

The mean age of the 107 patients was 84.1 years, with 59% being women. Significant improvements were observed in visual analog scale scores for lower back and lower extremities pain, Oswestry Disability Index, European Quality of Life-5 Dimensions, and painDETECT scores, indicating reduced pain, decreased disability, and enhanced quality of life. There were no significant differences in outcomes between patients aged 80 to 84 and those 85 or older. Surgery-related outcomes such as operation time, blood loss, and complications were similar in both age groups.

CONCLUSIONS

BED is a safe and effective treatment for LSS in octogenarians, providing significant pain relief and functional improvement. This minimally invasive technique is also viable for patients older than 85 years, without increased risk of complications, supporting its broader indications in managing LSS in the elderly.

CLINICAL RELEVANCE

This study highlights the efficacy and safety of BED for LSS in octogenarians, demonstrating its potential to improve quality of life and function with low risks, making it a feasible option for elderly patients.

LEVEL OF EVIDENCE: 4

Determining Differences in Perioperative Functional Mobility Patterns in Lumbar Decompression Versus Fusion Patients Using Smartphone Activity Data

BACKGROUND AND OBJECTIVES

Smartphone activity data recorded through high-fidelity accelerometry can provide accurate postoperative assessments of patient mobility. The "big data" available through smartphones allows for advanced analyses, yielding insight into patient well-being. This study compared rate of change in functional activity data between lumbar fusion (LF) and lumbar decompression (LD) patients to determine preoperative and postoperative course differences.

METHODS

Twenty-three LF and 18 LD patients were retrospectively included. Activity data (steps per day) recorded in Apple Health, encompassing over 70 000 perioperative data points, was classified into 6 temporal epochs representing distinct functional states, including acute preoperative decline, immediate postoperative recovery, and postoperative decline. The daily rate of change of each patient's step counts was calculated for each perioperative epoch.

RESULTS

Patients undergoing LF demonstrated steeper preoperative declines than LD patients based on the first derivative of step count data (P = .045). In the surgical recovery phase, LF patients had slower recoveries (P = .041), and LF patients experienced steeper postoperative secondary declines than LD patients did (P = .010). The rate of change of steps per day demonstrated varying perioperative trajectories that were not explained by differences in age, comorbidities, or levels operated.

CONCLUSION

Patients undergoing LF and LD have distinct perioperative activity profiles characterized by the rate of change in the patient daily steps. Daily steps and their rate of change is thus a valuable metric in phenotyping patients and understanding their postsurgical outcomes. Prospective studies are needed to expand upon these data and establish causal links between preoperative patient mobility, patient characteristics, and postoperative functional outcomes.

Isobar hybrid dynamic stabilization with posterolateral fusion in mild and moderate lumbar degenerative disease

OBJECTIVE

The aim of this study was to investigate the feasibility of using the Isobar TTL system and posterolateral fusion in a two-segment hybrid fixation approach, combined with spinal decompression, for treating mild and moderate lumbar degenerative disease. Specifically, we sought to evaluate the effectiveness of this approach for managing two-segment mild and moderate lumbar degenerative disease, and to determine whether it could provide a safe and reliable alternative to traditional surgical methods.

METHODS

This retrospective study included 45 consecutive patients with two-level lumbar disc herniation or spinal stenosis, 24 of whom underwent the TTL system and posterolateral fusion combined (TTL group), and 21 of whom underwent posterolateral fusion alone (Rigid group). The surgical segment, admission diagnosis, operation time, and intraoperative bleeding were recorded separately for the two groups of patients. Imaging studies included pre- and postoperative radiography, magnetic resonance imaging, and computed tomography. The clinical outcomes were measured by Oswestry Disability Index (ODI) scores, and a visual analogue scale (VAS) for back and leg pain.

RESULTS

All patients completed the surgery successfully with a mean follow-up of 56.09 months. The operative time and intraoperative bleeding were lower in the TTL group than in the Rigid group (p < 0.05). All patients showed significant improvements in clinical outcomes, including VAS for back and leg pain, and ODI scores (p < 0.05). ODI scores, the TTL group was better than the Rigid group at 1 year after surgery and at the final follow-up (p < 0.05). Postoperative surgical segment range of motion (ROM) decreased in both groups (p < 0.05). The postoperative ROM of the upper adjacent segment increased in both groups and was significantly higher in both groups at the last follow-up compared with the preoperative period (p < 0.05), and the superior adjacent segment rom of the TTL group was lower than the Rigid group (p < 0.05). The modified Pfrrmann classification of the superior adjacent segment was significantly increased in both groups at the last follow-up (p < 0.05). And in the TTL group, ROM, DH, and modified Pfrrmann grading of dynamic segment outperformed fusion segments. According to the UCLA classification, the incidence of adjacent segment degeneration (ASD) was 4.2% in the TTL group and 23.8% in the Rigid group, and the incidence of ASD was lower in the TTL group than in the Rigid group (P < 0.05).

CONCLUSION

The Isobar TTL System was utilized in two-level lumbar hybrid surgery, resulting in no evident indications of lumbar instability being detected on X-rays captured at a minimum of 4 years after the operation, while retaining partial range of motion of the surgical segment. The general clinical efficacy is equivalent to titanium rod fusion surgery, presenting an alternative treatment for individuals with mild and moderate lumbar degenerative disease.

Which is the most effective treatment for lumbar spinal stenosis: Decompression, fusion, or interspinous process device? A Bayesian network meta-analysis

Objective

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.

Materials and methods

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.

Results

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.

Conclusion

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.

The translational potential of this article

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.

Multi-segmental lumbar spinal stenosis treated with Dynesys stabilization versus lumbar fusion in elderly patients: a retrospective study with a minimum of 5 years' follow-up

INTRODUCTION

Middle- and long-term outcomes of multi-segmental lumbar spinal stenosis treated with Dynesys stabilization (DS) have rarely been reported. Older age and multi-segmental degeneration may be positive factors in achieving satisfactory outcomes following DS. The present study aimed to compare the middle- and long-term outcomes of DS with lumbar fusion for treatment of multi-segmental lumbar spinal stenosis (ms-LSS) in elderly patients.

MATERIALS AND METHODS

This study retrospectively analyzed patients with ms-LSS treated by DS or lumbar fusion from January 2011 to April 2013. Twenty-two patients were included in the Dynesys group, and 44 patients treated by lumbar fusion and rigid fixation were included in the fusion group. Clinical outcomes were assessed by VAS and ODI. Radiological outcomes were measured by range of motion (ROM) of stabilized segments and the proximal adjacent segment, intervertebral disc height (DH) and L1-S1 lumbar lordosis angle (LL). Modified Pfirrmann grade score was used to access disc degeneration.

OUTCOMES

The mean follow-up time of the Dynesys group and fusion group was 68.50 ± 6.40 and 70.14 ± 7.26 months, respectively. Baseline data were similar between the two groups. There were no significant differences between the two groups in terms of improvement of clinical outcomes (VAS and ODI). DS preserved a certain degree of ROM (3.74 ± 2.00) of surgical segments. ROM of proximal adjacent segment underwent an increase in both groups at the final follow-up. The DH of the surgical segments and proximal adjacent segment in both groups was significantly lower than that before surgery (P = 0.000). LL of both groups improved (P = 0.000), and there was no significant difference between the two groups. The modified Pfirrmann score of proximal adjacent segment of both groups increased at the final follow-up. The fusion group underwent a more significant increase (P = 0.000), whereas the inter-group difference showed no significance (P = 0.090).

CONCLUSION

DS is a safe and effective surgical treatment of multi-segmental lumbar spinal stenosis in the elderly population. DS preserves a certain degree of mobility of surgical segments.

SURGICAL TREATMENT OF ELDERLY AND SENILE PATIENTS WITH DEGENERATIVE CENTRAL LUMBAR SPINAL STENOSIS

Objective. To analyze the results of surgical treatment of patients of the older age group with central spinal stenosis at the lumbar level. Material and Methods. A total of 107 patients of elderly and senile age with clinically significant degenerative central stenosis of the spinal canal were treated. They were divided into two groups: patients in Group 1 underwent bilateral decompression of nerve roots through unilateral approach; those in Group 2 - nerve root decompression supplemented with interbody fusion and transpedicular fixation. Results. The surgery resulted in statistically significant reduction in pain, improvement of the quality of life, enlargement of spinal canal dimension parameters, and increase in the distance of walking. Statistical difference in the quality of life between Groups 1 and 2 was revealed for the indicator characterizing the psychological component of the SF-36 questionnaire (p = 0.03); there were no statistical differences for the remaining indicators. The key parameter for assessing central stenosis is the cross-sectional area of the dural sac. Conclusion. Preoperative examination of patients of the older age group should be comprehensive and include CT myelography with 3D reconstruction. The cause of nerve root compression in central stenosis is a combination of various factors in 41.9 % of cases. Differential surgical tactics provides an improvement in the quality of life in 80 % of cases. Excessive decompression does not improve the quality of life of patients. Instrumental fixation does not improve the outcome of surgical intervention and should be used only for clinically significant instability of the spinal motion segment.

The 2-Level Experience of Interlaminar Stabilization: 5-Year Follow-Up of a Prospective, Randomized Clinical Experience Compared to Fusion for the Sustainable Management of Spinal Stenosis

BACKGROUND

To alleviate the symptoms of lumbar spinal stenosis, widely accepted methods of surgical treatment include decompression alone and decompression with fusion. As an alternative to these methods, interlaminar stabilization (ILS) devices with decompression were introduced. There is a large amount of research dedicated to examining the efficacy of ILS devices in single-level procedures, but fewer studies focus on their efficacy in 2-level procedures. The purpose of this study was to compare decompression with instrumented posterolateral fusion to decompression with interlaminar stabilization in patients who require surgical treatment at 2 levels for lumbar spinal stenosis at 5 years postoperation.

METHODS

Of the 322 patients enrolled in the Investigational Device Exemption clinical trial, 116 required surgical treatment at 2 levels. The ILS group consisted of 77 patients, and the fusion group consisted of 39 patients. Efficacy was measured using composite clinical success (CCS). Patients achieve CCS if they achieve all 4 of the following outcomes: ≥15-point improvement from baseline Oswestry Disability Index (ODI); no reoperation or epidural injections; no persistent, new, or increasing neurological deficits; and no major device-related complications.

RESULTS

There was a 91% rate of follow-up within the participant population in the 5-year data. There was a difference trending toward significance between groups for the absence of reoperation or epidural injection, with 68.8% of ILS patients and only 51.3% of fusion patients meeting this criteria (P = .065); 13.0% of ILS patients and 25.7% of fusion patients required secondary surgery. The percentage of patients achieving overall CCS was much greater in the ILS group than the fusion group, with 55.1% (38/69) of ILS patients and only 36.4% (12/33) of fusion patients achieving CCS at month 60 (P = .077). With regard to the ODI, the visual analog scale back and worse leg pain, the Short Form-12, and the Zurich Claudication Questionnaire, both groups had significantly better results at every follow-up time point when compared to their respective baseline scores.

CONCLUSIONS

The 2-level ILS patient group performed as well as, if not better than, the 2-level fusion group across almost all outcome measures, demonstrating both clinical outcome success and favorably low reoperation rates in patients who received ILS surgery.

CLINICAL RELEVANCE

This is the first 5-year analysis of the 2-level ILS experience, which supplements previous studies that describe the advantages of ILS by extending such advantages to 2-level cases.

Which functional outcome parameters correlate better with elderly patients' satisfaction after non-fusion lumbar spine surgery?

BACKGROUND

Elderly patients are increasingly operated for spinal degenerative diseases. The treatment objective is quality of life, which, in this population, is difficult to assess. Hence, patient satisfaction, although less objective, is of high importance. In this study, we have examined the relation of various functional parameters after non-fusion spinal surgery, with patient satisfaction.

METHODS

A 5-year follow-up after non-fusion lumbar spine surgery on 185 elderly patients was performed. Demographics, co-morbidity factors, type of lesion and operation performed were recorded. The Oswestry Disability Index (ODI) was calculated. Also, walking distance, use of analgesics, daily activities, social life and patient mobility were assessed by means of study-specific stratified pain-independent questionnaires. Finally, patient satisfaction was assessed by the single-item satisfaction question.

RESULTS

Postoperative ODI, and the improvement regarding ODI, analgesic use and walking distance indices were independent factors influencing patient satisfaction. The insertion of pain analog scale score into this model altered the results, and along with this score, only the walking distance improvement remained an independent statistically significant factor. When the independent from pain scales were used, the improvement of the walking distance score were independently related to the satisfaction of the elderly.

CONCLUSIONS

ODI is applicable in elderly patients, even with the exception of some of the categories assessed. Walking capacity should be assessed separately from other pain-dependent activities; its improvement should be an independent goal of lumbar spine surgery in the elderly. The level of the elderly patient subjectivity in auto-assessing the outcome of lumbar spine surgery is high, and objective outcome measurements remain important.

Posterior Decompression and Fusion: Whole-Spine Functional and Clinical Outcomes

The mobility of the spine and the change in the angle of the curvatures are directly related to spinal pain and spinal stenosis. The aim of the study was the evaluation of morphology and mobility of the spine in patients who were subjected to decompression and posterior fusion with pedicle screws. The treatment group consisted of 20 patients who underwent posterior fixation of lumbar spine (one and two level fusion). The control group consisted of 39 healthy subjects. Mobility and curvatures of the spine were measured with a non-invasive device, the Spinal Mouse. Pain was evaluated with the Visual Analogue Scale (VAS). The Oswestry Disability Index (ODI) and the SF-36 were used to evaluate the degree of the functional disability and the quality of life, respectively. The measurements were recorded preoperatively and at 3, 6 and 12 months postoperatively. The mobility of the lumbar spine in the sagittal plane increased (p = 0.009) at 12 months compared to the measurements at 3 months. The mobility of the thoracic spine in the frontal plane increased (p = 0.009) at 12 months compared to the preoperative evaluation. The results of VAS, ODI and SF-36 PCS improved significantly (p<0.001). The levels of fusion exhibited a strong linear correlation (r = 0.651, p = 0.002) with the total trunk inclination in the upright position. Although pain, quality of life and spinal mobility in the sagittal and frontal planes significantly improved in the treatment group, these patients still had limited mobility and decreased curves/angles values compared to control group.

Microsurgical unilateral laminotomy for decompression of lumbar spinal stenosis: long-term results and predictive factors

BACKGROUND

The microsurgical unilateral laminotomy (MUL) technique for bilateral decompression of lumbar spinal stenosis (LSS) is a less destabilizing alternative to laminectomy and leads to good short-term outcomes. However, little is known about the long-term results including predictive factors.

METHODS

Medical records of patients who underwent MUL for LSS decompression between 2005 and 2010 were reviewed, and a questionnaire was distributed to complement the long-term outcome data. The study population consisted of 176 patients including 17 patients with stable grade I spondylolisthesis. Complications and reoperations were meticulously analyzed. Clinical outcome was measured using a modified Prolo scale and was further dichotomized in good vs. poor outcome. Predictive factors were obtained from uni- and multivariate analyses.

RESULTS

The median age of the cohort was 70.0 years and the follow-up 71.7 months. Complications occurred in 5.1 % of the patients. The overall reoperation rate was 17.0 %, including surgery, which was exclusively performed at other levels in 4.0 %. The reoperation rate for fusion was 4.5 %. Good neurogenic claudication outcome faded from 98.3 % at hospital discharge to 47.2 % at 6 years. Multivariate analysis identified previous lumbar operation as a potential independent predictor of a reoperation; potential independent predictors of poor long-term claudication outcome were older age, female gender, higher body mass index (BMI) and tobacco smoking.

CONCLUSIONS

In our experience, the long-term reoperation rate after MUL for LSS is not negligible and higher in previously operated patients. It seems like the good initial clinical results after MUL may fade over time, and several patient-related predictive factors including potentially modifiable obesity and tobacco smoking seem to play an important role.

Stand-alone interspinous spacer versus decompressive laminectomy for treatment of lumbar spinal stenosis

OBJECTIVE

To compare the two-year clinical outcomes of a prospective, randomized controlled trial of an FDA-approved interspinous spacer with the compilation of published findings from 19 studies of decompressive laminectomy for the treatment of lumbar spinal stenosis.

METHODS

Back and leg pain, Oswestry disability index (ODI), and Zurich Claudication Questionnaire (ZCQ) values were compared between spacer- and laminectomy-treated patients preoperatively and at 12 and 24 months.

RESULTS

Percentage improvements between baseline and 24 months uniformly favored patients treated with the spacer for back pain (65% vs. 52%), leg pain (70% vs. 62%), ODI (51% vs. 47%) and ZCQ symptom severity (37% vs. 29%) and physical function (36% vs. 32%).

CONCLUSION

Both treatments provide effective and durable symptom relief of claudicant symptoms. This stand-alone interspinous spacer offers the patient a minimally invasive option with less surgical risk.

Effect of fusion following decompression for lumbar spinal stenosis: a meta-analysis and systematic review

PURPOSE

The surgical methods of degenerative lumbar spinal stenosis include spinal decompression with or without instrumented or non-instrumented spinal fusion. Previous meta-analysis and systematic reviews have reported the contrast between surgical management and nonsurgical management for degenerative lumbar spinal stenosis, while no literature did among surgical managements. And it is evidenced that whether fusion should be added to spinal decompression in patients of lumbar spinal stenosis is still divisive. So our purpose is to identify whether spinal fusion with or without decompression has a better effect than decompression alone for patients with degenerative lumbar spinal stenosis.

METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) for reports before November 2014 and PubMed, EMBASE, GOOGLE SCHOLAR for those before December 2014. We also searched the reference lists included in studies and previous reviews. Randomized Controlled Trials and prospective or retrospective cohort studies of patients with degenerative lumbar spinal stenosis after spinal decompression with or without fusion were eligible. Abstracted outcomes from retrieved articles included clinical outcome and reoperation rate of two aspects. Both random-effects and fixed-effects models were used to calculate the end-points.

RESULTS

We identified 23 studies with data collected from 61576 patients. The combined relative risk (RR) of clinical outcome for the spinal fusion compared with the spinal decompression was 0.91 (95% confidence interval [CI]: 0.85 to 0.98), and little evidence of heterogeneity was observed. Namely, a satisfactory clinical outcome was significantly more likely with fusion than with decompression alone. But there was a trend toward a higher reoperation rate with fusion compared with decompression alone (RR: 0.93; 95% CI: 0.88 to 0.97).

CONCLUSION

This meta-analysis provides robust evidence of a better clinical outcome but a higher reoperation rate for spinal fusion compared with decompression alone.

Biomechanical analysis of an interspinous fusion device as a stand-alone and as supplemental fixation to posterior expandable interbody cages in the lumbar spine

OBJECT

In this paper the authors evaluate through in vitro biomechanical testing the performance of an interspinous fusion device as a stand-alone device, after lumbar decompression surgery, and as supplemental fixation to expandable cages in a posterior lumbar interbody fusion (PLIF) construct.

METHODS

Nine L3-4 human cadaveric spines were biomechanically tested under the following conditions: 1) intact/control; 2) L3-4 left hemilaminotomy with partial discectomy (injury); 3) interspinous spacer (ISS); 4) bilateral pedicle screw system (BPSS); 5) bilateral hemilaminectomy, discectomy, and expandable posterior interbody cages with ISS (PLIF-ISS); and 6) PLIF-BPSS. Each test consisted of 100 N of axial preload with ± 7.5 Nm of torque in flexion-extension, right/left lateral bending, and right/left axial rotation. Significant changes in range of motion (ROM), neutral zone stiffness (NZS), elastic zone stiffness (EZS), and energy loss (EL) were explored among conditions using nonparametric Friedman test and Wilcoxon signed-rank comparisons (p ≤ 0.05).

RESULTS

The injury increased ROM in flexion (p = 0.01), left bending (p = 0.03), and right/left rotation (p < 0.01) and also decreased NZS in flexion (p = 0.01) and extension (p < 0.01). Both the ISS and BPSS reduced flexion-extension ROM and increased flexion-extension stiffness (NZS and EZS) with respect to the injury and intact conditions (p < 0.05), but the ISS condition provided greater resistance than BPSS in extension for ROM, NZS, and EZS (p < 0.01). The BPSS increased the rigidity (ROM, NZS, and EZS) of the intact model in lateral bending and axial rotation (p ≤ 0.01), except in EZS for left rotation (p = 0.23, Friedman test). The incorporation of posterior cages marginally increased (p = 0.05) the EZS of the BPSS construct in flexion but these interbody devices provided significant stability to the ISS construct in lateral bending and axial rotation for ROM (p = 0.02), in lateral bending for NZS (p = 0.02), and in flexion/axial rotation for EZS (p ≤ 0.03); however, both PLIF constructs demonstrated equivalent ROM and stiffness (p ≥ 0.16), except in lateral bending where the PLIF-BPSS was more stable (p = 0.02). In terms of EL, the injury increased EL in flexion-extension (p = 0.02), the ISS increased EL for lateral bending and axial rotation (p ≤ 0.03), and the BPSS decreased EL in lateral bending (p = 0.02), with respect to the intact condition. The PLIF-ISS decreased lateral bending EL with respect to the ISS condition (p = 0.02), but not enough to be smaller or, at least, equivalent, to that of the PLIF-BPSS construct (p = 0.02).

CONCLUSIONS

The ISS may be a suitable device to provide immediate flexion-extension balance after a unilateral laminotomy, but the BPSS provides greater immediate stability in lateral bending and axial rotation motions. Both PLIF constructs performed equivalently in flexion-extension and axial rotation, but the PLIF-BPSS construct is more resistant to lateral bending motions. Further biomechanical and clinical evidence is required to strongly support the recommendation of a stand-alone interspinous fusion device or as supplemental fixation to expandable posterior interbody cages.

Analysis of factors contributing to postoperative spinal instability after lumbar decompression for spinal stenosis

Objective

Decompressive laminectomy is one of the most commonly used surgical methods for the treatment of spinal stenosis. We retrospectively examined the risk factors that induce spinal instability, including slippage (spondylolisthesis) and/or segmental angulation after decompressive laminectomy on the lumbar spine.

Methods

From January 1, 2006 to June 30, 2010, 94 consecutive patients underwent first-time single level decompressive laminectomy without fusion and discectomy. Of these 94 patients, 42 with a follow-up period of at least 2 years were selected. We measured the segmental angulation and slippage in flexion and extension dynamic lumbar radiographs. We analyzed the following contributing factors to spinal instability: age/sex, smoking history, disc space narrowing, body mass index (kg/m²), facet joint tropism, effect of the lordotic angle on lumbar spine, asymmetrical paraspinal muscle volume, and surgical method and level.

Results

Female patients, normal lordotic angle, and asymmetrical paraspinal muscle volume were factors more significantly associated with spondylolisthesis (p-value=0.026, 0.015, <0.01). Statistical results indicated that patients with facet tropism were more likely to have segmental angulation (p-value=0.046). Facet tropism and asymmetry of paraspinal muscle volume were predisposing factors to spinal instability (p-value=0.012, <0.01).

Conclusion

Facet joint tropism and asymmetry of paraspinal muscle volume are the most important factors associated with spinal instability; therefore, careful follow-up after decompressive laminectomy in affected patients is necessary.