Laminectomy plus Fusion versus Laminectomy Alone for Lumbar Spondylolisthesis

Lumbar Spinal Stenosis with Degenerative Spondylolisthesis Treated with Decompression Alone. A Cohort of 346 Patients at a Large Spine Unit. Clinical Outcome, Complications and Subsequent Surgery

STUDY DESIGN

Cohort study.

OBJECTIVE

To study the clinical outcome, complications and subsequent surgery rate of DA for lumbar spinal stenosis (LSS) with DS.

SUMMARY OF BACKGROUND DATA

There is still no consensus regarding the treatment approach for LSS with DS.

METHODS

We performed a retrospectively designed cohort study on prospectively collected data from a single high productive spine surgical center. Results from the Swedish Spine Registry and a local register for complications were used for the analyses. Patients with LSS and DS (>3 mm) who underwent DA during January 2012 to August 2017 were included. Patient reported outcome measures at baseline and 2 years after surgery were analyzed. Complications within 30 days of surgery and all subsequent surgery in the lumbar spine were registered.

RESULTS

We identified and included 346 patients with completed 2-year follow-up registration. At 2-year follow-up there was a significant improvement in all outcome measures. The global assessment success rate for back and leg pain was 68.3% and 67.6% respectively. Forty-one patients had at least 1 intra- or postoperative complication (11.9%). Nine patients (2.6%), underwent subsequent surgery within 2 years of the primary surgery whereof 2 underwent fusion. During the whole period of data collection, that is, as of June 2020, 28 patients had undergone subsequent surgery (8.1%) whereas 8 of them had had 2 surgeries. Fifteen patients underwent fusion.

CONCLUSION

DA provides good clinical outcome at 2-year follow-up in patients with LSS and DS with low rate of intra- and postoperative complications and subsequent surgery. Our data supports the evidence that DA is effective and safe for LSS with DS.Level of Evidence: 3.

Evaluation of the Predictors for Unfavorable Clinical Outcomes of Degenerative Lumbar Spondylolisthesis After Lumbar Interbody Fusion Using Machine Learning

Background

An increasing number of geriatric patients are suffering from degenerative lumbar spondylolisthesis (DLS) and need a lumbar interbody fusion (LIF) operation to alleviate the symptoms. Our study was performed aiming to determine the predictors that contributed to unfavorable clinical efficacy among patients with DLS after LIF according to the support vector machine (SVM) algorithm.

Methods

A total of 157 patients with single-segment DLS were recruited and performed LIF in our hospital from January 1, 2015 to October 1, 2020. Postoperative functional evaluation, including ODI and VAS were, performed, and endpoint events were defined as significant relief of symptom in the short term (2 weeks postoperatively) and long term (1 year postoperatively). General patient information and radiological data were selected and analyzed for statistical relationships with the endpoint events. The SVM method was used to establish the predictive model.

Results

Among the 157 consecutive patients, a postoperative unfavorable clinical outcome was reported in 26 patients (16.6%) for a short-term cohort and nine patients (5.7%) for a long-term cohort. Based on univariate and multivariate regression analysis, increased disc height (DH), enlarged facet angle (FA), and raised lateral listhesis (LLS) grade were confirmed as the risk factors that hindered patients' short-term functional recovery. Furthermore, long-term functional recovery was significantly associated with DH alone. In combination with the SVM method, a prediction model with consistent and superior predictive performance was achieved with average and maximum areas under the receiver operating characteristic curve (AUC) of 0.88 and 0.96 in the short-term cohort, and 0.78 and 0.82 in the long-term cohort. The classification results of the discriminant analysis were demonstrated by the confusion matrix.

Conclusions

The proposed SVM model indicated that DH, FA, and LLS were statistically associated with a clinical outcome of DLS. These results may provide optimized clinical strategy for treatment of DLS.

Facet Joint Opening on Computed Tomography Is a Predictor of Poor Clinical Outcomes After Minimally Invasive Decompression Surgery for Lumbar Spinal Stenosis

STUDY DESIGN

Retrospective longitudinal cohort study.

OBJECTIVE

To investigate the impact of facet joint opening (FJO) on clinical outcomes after minimally invasive decompression surgery for lumbar spinal stenosis.

SUMMARY OF BACKGROUND DATA

Although FJOs have previously been identified as indicators of segmental spinal instability, their impact on clinical outcomes after decompression alone surgery has yet to be investigated.

METHODS

This study included 296 patients from a single institution who underwent minimally invasive surgery for lumbar spinal stenosis and were followed up for ≥5 years. Our analysis focused on identifying FJOs at the index decompression level (d-FJO) and at multiple levels (m-FJO) (i.e., ≥3 levels within the lumbar segment) using preoperative computed tomography. Clinical outcomes including reoperations, improvement ratio for Japanese Orthopaedic Association score, and achievement of a minimal clinically important difference in visual analogue scale scores for low back pain or leg pain at 5 years were compared between patients with and without d-FJO or m-FJO.

RESULTS

There were 129 (44%) and 62 (21%) patients with d-FJO (more common with lateral olisthesis) and m-FJO (less common with spondylolisthesis), respectively. Reoperations were more common in patients with d-FJO than in those without (16% vs. 5%). On Cox proportional hazards analysis, d-FJO was identified as a predictor for revision at the index decompression level (hazard ratio 4.04, P = 0.03), whereas m-FJO was a predictor for revision at other lumbar levels (hazard ratio 3.71, P = 0.03). Patients with m-FJO had slightly lower rates of achieving minimal clinically important difference in visual analogue scale scores for low back pain (34% vs. 52%, P = 0.03) and poorer improvement ratio for Japanese Orthopaedic Association scores (74% vs. 80%, P = 0.03) than those without.

CONCLUSION

FJO at both index decompression level and multiple level were predictors of poor outcomes; patients with FJOs require careful surgical planning or special follow-up.Level of Evidence: 3.

Decompression Alone Compared to Decompression With Fusion in Patients With Lumbar Spondylolisthesis: Systematic Review, Meta-Analysis, and Meta-Regression

BACKGROUND

We aimed to synthesize the latest evidence on the efficacy and safety of decompression alone compared to decompression with fusion in patients with lumbar spondylolisthesis. We also aimed to evaluate factors affecting the efficacy and complications.

METHODS

A systematic literature search was conducted using PubMed, Scopus, Europe PMC, Cochrane Central Database, and ClinicalTrials.gov. The main outcome was improvement in Oswestry Disability Index (ODI). The secondary outcome was back pain and leg pain improvement, complications, reoperation rate, duration of surgery, length of hospital stay, and blood loss.

RESULTS

There were 3993 patients from 13 studies. Decompression with fusion was associated with greater reduction in ODI (mean difference 4.04 [95% CI 0.95, 7.13], P = 0.01) compared to decompression alone. Greater reduction in back (standardized mean difference [SMD] 0.27 [95% CI 0.00, 0.53], P = 0.05) and leg pain (SMD 0.13 [95% CI 0.06, 0.21], P < 0.001) was observed in the decompression with fusion group. Complications were similar in the 2 groups (OR 0.60 [95% CI 0.34, 1.04], P = 0.07). The reoperation rate was similar in both groups (P = 0.54). Decompression alone resulted in shorter duration of surgery (mean difference -85.18 minutes [95% CI -122.79, -47.57], P < 0.001), less blood loss (mean difference -262.65 mL [95% CI -313.45, -211.85], P < 0.001), and shorter hospital stay (mean difference -2.64 days [95% CI -3.58, -1.70], P < 0.001). Empirical Bayes random-effects meta-regression showed that the rate of complication was influenced by age (coefficient 0.172, P = 0.004).

CONCLUSION

Decompression with fusion had greater efficacy than decompression alone but was associated with more blood loss, lengthier surgery, and hospitalization. In terms of complications, decompression alone may be beneficial in younger patients. (PROSPERO CRD42020211904) LEVEL OF EVIDENCE: 2A.

Effect of Minimally Invasive Selective Laminectomy for Cervical Spondylotic Myelopathy on Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective analysis of prospectively collected observational data.

OBJECTIVE

This study aimed to evaluate the slippage, sagittal alignment, and range of motion (ROM) after selective laminectomy (SL) in patients who had cervical spondylotic myelopathy (CSM) with degenerative spondylolisthesis (DS).

SUMMARY OF BACKGROUND DATA

Clinical outcomes have been reported for both decompression and fusion surgeries for DS of the lumbar spine. However, only a few reports have examined cervical spine spondylolisthesis.

MATERIALS AND METHODS

This study included 178 patients who underwent SL for CSM. Those with ossification of the posterior longitudinal ligament were excluded. Slippage >2 mm was defined as spondylolisthesis, and spondylolisthesis progression was defined as an additional displacement >2 mm on a neutral radiograph. The slippage, translational motion, C2-C7 angle, local kyphosis, and ROM were examined before and ≥2 years after surgery. Radiologic parameters were evaluated according to the slip direction and the number of laminae removed.

RESULTS

DS was observed in 29 patients (16.3%); 24 patients, comprising 9 and 15 in the anterolisthesis and retrolisthesis groups, respectively, were successfully followed up for more than 2 years. Preoperative and postoperative radiologic changes in slippage, translational motion, C2-C7 angle, local kyphosis, and ROM were not remarkable in either group regardless of the number of laminae removed. Revision surgery for the progression of DS and alignment deterioration was not required in any patient of either group.

CONCLUSIONS

SL does not affect DS, sagittal alignment, or ROM irrespective of the slip direction and the number of laminae removed, even after >2 years after surgery. Given the preservation of the posterior elements, SL may be an effective treatment for CSM with DS.

LEVEL OF EVIDENCE

Level IV.

Does reduction of the Meyerding grade correlate with outcomes in patients undergoing decompression and fusion for grade I degenerative lumbar spondylolisthesis?

OBJECTIVE

Reduction of Meyerding grade is often performed during fusion for spondylolisthesis. Although radiographic appearance may improve, correlation with patient-reported outcomes (PROs) is rarely reported. In this study, the authors' aim was to assess the impact of spondylolisthesis reduction on 24-month PRO measures after decompression and fusion surgery for Meyerding grade I degenerative lumbar spondylolisthesis.

METHODS

The Quality Outcomes Database (QOD) was queried for patients undergoing posterior lumbar fusion for spondylolisthesis with a minimum 24-month follow-up, and quantitative correlation between Meyerding slippage reduction and PROs was performed. Baseline and 24-month PROs, including the Oswestry Disability Index (ODI), EQ-5D, Numeric Rating Scale (NRS)-back pain (NRS-BP), NRS-leg pain (NRS-LP), and satisfaction (North American Spine Society patient satisfaction questionnaire) scores were noted. Multivariable regression models were fitted for 24-month PROs and complications after adjusting for an array of preoperative and surgical variables. Data were analyzed for magnitude of slippage reduction and correlated with PROs. Patients were divided into two groups: < 3 mm reduction and ≥ 3 mm reduction.

RESULTS

Of 608 patients from 12 participating sites, 206 patients with complete data were identified in the QOD and included in this study. Baseline patient demographics, comorbidities, and clinical characteristics were similarly distributed between the cohorts except for depression, listhesis magnitude, and the proportion with dynamic listhesis (which were accounted for in the multivariable analysis). One hundred four (50.5%) patients underwent lumbar decompression and fusion with slippage reduction ≥ 3 mm (mean 5.19, range 3 to 11), and 102 (49.5%) patients underwent lumbar decompression and fusion with slippage reduction < 3 mm (mean 0.41, range 2 to -2). Patients in both groups (slippage reduction ≥ 3 mm, and slippage reduction < 3 mm) reported significant improvement in all primary patient reported outcomes (all p < 0.001). There was no significant difference with regard to the PROs between patients with or without intraoperative reduction of listhesis on univariate and multivariable analyses (ODI, EQ-5D, NRS-BP, NRS-LP, or satisfaction). There was no significant difference in complications between cohorts.

CONCLUSIONS

Significant improvement was found in terms of all PROs in patients undergoing decompression and fusion for lumbar spondylolisthesis. There was no correlation with clinical outcomes and magnitude of Meyerding slippage reduction.

Artificial Intelligence Algorithm-Based Lumbar and Spinal MRI for Evaluation of Efficacy of Chinkuei Shin Chewan Decoction on Lumbar Spinal Stenosis

The study aimed to explore the application value of lumbar Magnetic Resonance Imaging (MRI) images processed by artificial intelligence algorithms in evaluating the efficacy of chinkuei shin chewan decoction (a traditional Chinese medicine to nourish the kidney) in the treatment of lumbar spinal stenosis (LSS). Specifically, 110 LSS patients admitted to the hospital were selected as the research subjects. They were randomly divided into the control group (n = 55) and experimental group (n = 55) according to different treatment methods. The control group was treated with traditional medicine, and the experimental group additionally took chinkuei shin chewan decoction on its basis. Based on the traditional U-net algorithm, a U-net registration algorithm based on artificial intelligence was designed by introducing the information entropy theory, and the algorithm was applied to the lumbar MRI image evaluation of LSS patients. Compared with the traditional U-net algorithm, the artificial intelligence-based U-net registration algorithm had a decreased noise level (P < 0.05), the Jaccard (J) value (0.84) and the Dice value (0.93) increased significantly versus the traditional algorithm (J = 0.63, Dice = 0.81), and the characteristics of the image were more accurate. Before treatment, the Oswestry Disability Index (ODI) scores of the experimental group and the control group were 44.32 ± 6.45 and 43.32 ± 5.45, respectively. After treatment, the ODI scores of the two groups were 10.21 ± 5.05 and 17.09 ± 5.23, respectively. Both showed significant improvement, while the improvement of the experimental group was more obvious than that of the control group (P < 0.05). The overall effective rates of the two groups of patients were 96.44% and 82.47%, respectively, and the experimental group was significantly higher than the control group (P < 0.05). Under the U-net registration algorithm based on artificial intelligence, the diagnostic accuracy of lumbar MRI in the experimental group was 94.45%, significantly higher than 67.5% before the introduction of the algorithm (P < 0.05). In conclusion, chinkuei shin chewan decoction are effective for the treatment of LSS, and lumbar MRI based on the artificial intelligence U-net registration algorithm can evaluate the efficacy of LSS well and is worthy of promotion.

Hybrid surgery with PEEK rods for lumbar degenerative diseases: a 2-year follow-up study

Background

Finite element analyses and biomechanical tests have shown that PEEK rods promote fusion and prevent adjacent segment degeneration. The purpose of this study was to evaluate the effects and complications of hybrid surgery with PEEK rods in lumbar degenerative diseases.

Methods

From January 2015-December 2017, 28 patients who underwent lumbar posterior hybrid surgery with PEEK rods were included in the study. The patients were diagnosed with lumbar disc herniation, lumbar spinal stenosis, or degenerative grade I spondylolisthesis. Before the operation and at the last follow-up, the patients completed lumbar anteroposterior and lateral X-ray, dynamic X-ray, MRI examinations. In addition, at the last follow-up the patients also completed lumbar CT examinations. The radiographic parameters, clinical visual analog scale (VAS) score and Oswestry disability index (ODI) score were compared.

Results

The average age of the patients was 44.8 ± 12.6 years, and the average follow-up duration was 26.4 ± 3.6 months. The VAS score improved from 6.3 ± 1.6 to 1.0 ± 0.9, and the ODI score decreased from 38.4 ± 10.8 to 6.8 ± 4.6. The fusion rate of the fused segment was 100%. There were no significant changes in the modified Pfirrmann classifications or disc height index for the nonfused segments and the upper adjacent segments from pre- to postoperatively. No cases of screw loosening, broken screws, broken rods or other mechanical complications were found.

Conclusion

Hybrid surgery with PEEK rods for lumbar degenerative diseases can yield good clinical results and effectively reduce the incidence of complications such as adjacent segment diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04895-1.

Endoscopic modified total laminoplasty for symptomatic lumbar spinal stenosis

Context/objective: At present, there is no consensus on the most effective surgical method for treating symptomatic lumbar spinal stenosis (LSS). Total laminectomy, which is frequently used at this time, destroys the posterior midline structure, causing many postoperative complications. We have designed a new surgical approach instead of total laminectomy. In this paper, we aimed to describe the surgical method of endoscopic modified total laminectomy for lumbar spinal stenosis as well as to explore its early efficacy.Participants: Patients with symptomatic LSS who underwent endoscopic modified total laminoplasty between August 2016 and August 2017 were eligible for our study.Outcome measures: Before surgery and one year after surgery, we measured lower limb pain and back pain by visual analog scale (VAS), disability via Oswestry Disability Index (ODI), and severity of back pain according to the Japanese Orthopedic Association Score for Back Pain (JOA), while any complications were also assessed.Results: Endoscopic modified total laminoplasty was performed on 22 LSS patients, including eight males and 14 females(mean age = 59.3 ± 9.6 years). We found statistically significant differences before and one year after surgery for VAS lower limb pain and back pain, ODI and JOA scores(P < 0.001). Complications included intraoperative dural tears(n = 1),and weak fusion between the lamina and the vertebral body (n = 1).Conclusion: Endoscopic modified total laminectomy is a promising surgical approach which reduces patient suffering and improves patient quality of life.

Minimally invasive microsurgical decompression in patients with monosegmental lumbar spinal stenosis

Surgical treatment of degenerative lumbar spinal stenosis is an actual problem of modern spinal surgery and orthopedics.

OBJECTIVE

To analyze the results of minimally invasive microsurgical decompression (MI-MD) in patients with monosegmental lumbar spinal stenosis.

MATERIAL AND METHODS

A retrospective observational cohort study was performed. We analyzed medical records of patients who underwent MI-MD for monosegmental degenerative lumbar spinal stenosis. Clinical and objective results of MI-MD, as well as the types and prevalence of adverse clinical events were studied.

RESULTS

The study included 96 medical records (50 (52%) males and 46 (48%) females aged 18-84 years). Analysis of pain in lower back and lower extremities in 3, 6, 9, 12 and 24 months after MI-MD showed a significant decrease of this indicator (p<0.001). There was significant improvement of capacity according to ODI score up to 5-12% in 72.9% of patients in early postoperative period (p=0.055). In delayed postoperative period, we also observed significant improvement of working capacity according to ODI score and gradual decrease in disability index (p<0.001). Adverse clinical events occurred in 6 (6.2%) patients.

CONCLUSION

MI-MD is a highly effective surgical method for monosegmental lumbar spinal stenosis with minimal incidence of adverse clinical events.

Does change in focal lordosis after spinal fusion affect clinical outcomes in degenerative spondylolisthesis?

Study Design:

Retrospective cohort study.

Objective:

The objective of this study is to determine the effect of focal lordosis and global alignment and proportion (GAP) scores on patient reported outcome measures (PROMs) after posterior lumbar fusion for patients with 1- or 2-level lumbar degenerative spondylolisthesis (DS).

Summary of Background Data:

In patients with DS, improvements in spinopelvic parameters are believed to improve clinical outcomes. However, the effect of changing focal lordosis in patients with 1-or 2-level degenerative lumbar spondylolisthesis is unclear.

Materials and Methods:

Postoperative spinopelvic parameters and perioperative focal lordosis changes were measured for 162 patients at a single academic center from January 2013 to December 2017. Patients were divided into three groups: >2° (lordotic group), between 2° and −2° (neutral group), and −2°° (kyphotic group). Patients were then reclassified based on GAP scores. Recovery ratios (RR) and the number of patients achieving the minimal clinically important difference (MCID) were calculated for PROMs. Standard descriptive statistics were reported for patient demographics and outcomes data. Multiple linear regression analysis controlled for confounders. Alpha was set at P < 0.05.

Results:

There was no significant association between change in focal lordosis and surgical complications including adjacent segment disease (P = 0.282), instrumentation failure (P = 0.196), pseudarthrosis (P = 0.623), or revision surgery (P = 0.424). In addition, the only PROM affected by change in focal lordosis was Mental Component Scores (ΔMCS-12) (lordotic = 2.5, neutral = 8.54, and kyphotic = 5.96, P = 0.017) and RR for MCS-12 (lordotic = 0.02, neutral = 0.14, kyphotic 0.10, P = 0.008). Linear regression analysis demonstrated focal lordosis was a predictor of decreased improvement in MCS-12 (β = −6.45 [−11.03- −1.83], P = 0.007). GAP scores suggested patients who were correctly proportioned had worse MCID compared to moderately disproportioned and severely disproportioned patients (P = 0.024).

Conclusions:

The change in focal lordosis not a significant predictor of change in PROMs for disability, pain, or physical function. Proportioned patients based on the GAP score had worse MCID for Oswestry Disability Index.

Level of Evidence:

III

Revision Surgery for Adjacent Segment Degeneration After Fusion for Lumbar Spondylolisthesis: Is there a Correlation with Roussouly Type?

STUDY DESIGN

Retrospective study.

OBJECTIVE

The aim of this study was to investigate whether there is an association between revision surgery rates for adjacent segment degeneration (ASD) and Roussouly type after L4-5 transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Revision surgery for ASD is known to occur after spinal fusion; however, it is unclear whether rates of ASD are associated with certain Roussouly types.

METHODS

Patients who underwent L4-5 TLIF for spondylolisthesis at the University of California San Francisco from January 2006 to December 2016 with minimum 2-year follow-up were retrospectively analyzed by Roussouly type. Revision surgery for ASD was noted and correlated by Roussouly type. Spinopelvic parameters were also measured for correlation. A value of P < 0.05 was significant.

RESULTS

There were 174 patients who met inclusion criteria, (59 males and 115 females). The average age was 62.3 (25-80) years. A total of 132 patients had grade I spondylolisthesis, and 42 had grade II. Mean follow-up was 45.2 months (24-497). A total of 22 patients (12.6%) underwent revision surgery for ASD after L4-5 TLIF. When classified by Roussouly type, revision surgery rates for ASD were: 1, 14.3%; 2, 22.6%; 3, 4.9%; and 4, 15.6% (P = 0.013). Type 3 spines with normal PI-LL (8.85° ± 6.83°) had the lowest revision surgery rate (4.9%), and type 2 spines with PI-LL mismatch (11.06° ± 8.81°) had the highest revision surgery rate (22.6%), a four-fold difference (P = 0.013). The PI-LL mismatch did not change significantly in each type postoperatively (P > 0.05).

CONCLUSION

We found that there may be a correlation between Roussouly type and revision surgery for ASD after L4-5 TLIF for spondylolisthesis, with type 2 spines having the highest rate. Spinopelvic parameters may also correlate with revision surgery for ASD after L4-5 TLIF.Level of Evidence: 4.

Diagnostic Accuracy of SSEP Changes During Lumbar Spine Surgery for Predicting Postoperative Neurological Deficit: A Systematic Review and Meta-Analysis

STUDY DESIGN

This study is a meta-analysis of prospective and retrospective studies identified in PubMed, Web of Science, and Embase with outcomes of patients who received intraoperative somatosensory-evoked potential (SSEP) monitoring during lumbar spine surgery.

OBJECTIVE

The objective of this study is to determine the diagnostic accuracy of intraoperative lower extremity SSEP changes for predicting postoperative neurological deficit. As a secondary analysis, we evaluated three subtypes of intraoperative SSEP changes: reversible, irreversible, and total signal loss.

SUMMARY OF BACKGROUND DATA

Lumbar decompression and fusion surgery can treat lumbar spinal stenosis and spondylolisthesis but carry a risk for nerve root injury. Published neurophysiological monitoring guidelines provide no conclusive evidence for the clinical utility of intraoperative SSEP monitoring during lumbar spine surgery.

METHODS

A systematic review was conducted to identify studies with outcomes of patients who underwent lumbar spine surgeries with intraoperative SSEP monitoring. The sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated and presented with forest plots and a summary receiver operating characteristic curve.

RESULTS

The study cohort consisted of 5607 patients. All significant intraoperative SSEP changes had a sensitivity of 44% and specificity of 97% with a DOR of 22.13 (95% CI, 11.30-43.34). Reversible and irreversible SSEP changes had sensitivities of 28% and 33% and specificities of 97% and 97%, respectively. The DORs for reversible and irreversible SSEP changes were 13.93 (95% CI, 4.60-40.44) and 57.84 (95% CI, 15.95-209.84), respectively. Total loss of SSEPs had a sensitivity of 9% and specificity of 99% with a DOR of 23.91 (95% CI, 7.18-79.65).

CONCLUSION

SSEP changes during lumbar spine surgery are highly specific but moderately sensitive for new postoperative neurological deficits. Patients who had postoperative neurological deficit were 22 times more likely to have exhibited intraoperative SSEP changes.Level of Evidence: 2.

Decompression Using Minimally Invasive Surgery for Lumbar Spinal Stenosis Associated with Degenerative Spondylolisthesis: A Review

Lumbar spinal stenosis (LSS), which often occurs concurrently with degenerative spondylolisthesis (DS), is a common disease in the elderly population, affecting the quality of life of aged people significantly. Notwithstanding the frequently good effect of conservative therapy on LSS, a minority of the patients ultimately require surgery. Surgery for LSS aims to decompress the narrowed spinal canals with preservation of spinal stability. Traditional open surgery, either pure decompression or decompression with fusion, was considered effective for the treatment of LSS with or without DS. However, the long-term clinical outcomes of traditional open surgery are still unclear. Moreover, the disadvantages of conventional open surgery are extensive, examples including tissue injuries or secondary instability, with limited outcomes and significant reoperation rates. With the development and improvement of surgical tools, various minimally invasive spine surgery (MISS) methods, including indirect decompression techniques of interspinous process devices (IPDs) and direct decompression techniques such as microscopic spine surgery or endoscopic spine surgery (ESS), have been updated with enhancement. IPDs, such as Superion devices, were reported to behave with comparable physical function, disability, and symptoms outcomes to laminectomy decompression. As an emerging technique of MISS, ESS has beneficial hallmarks including minimal tissue injuries, reduced complication rates, and shortened recovery periods, thus gaining popularity in recent years. ESS can be classified in terms of endoscopic hallmarks and approaches. Predictably, with the continuous development and gradual maturity, MISS is expected to replace traditional open surgery widely in the surgical treatment of LSS associated with DS in the future.

Comparison of cost and complication rates for profiling hospital performance in lumbar fusion for spondylolisthesis

BACKGROUND CONTEXT

There is growing interest among payers in profiling hospital value and quality-of-care, including both the cost and safety of common surgeries, such as lumbar fusion. Nonetheless, there is sparse evidence describing the statistical reliability of such measures when applied to lumbar fusion for spondylolisthesis.

PURPOSE

To evaluate the reliability of 90-day inpatient hospital costs, overall complications, and rates of serious complications for profiling hospital performance in lumbar fusion surgery for spondylolisthesis.

STUDY DESIGN/SETTING

Data for this analysis came from State Inpatient Databases from nine states made available through the Healthcare Cost and Utilization Project.

PATIENT SAMPLE

Patients undergoing elective lumbar spine fusion for spondylolisthesis from 2010 to 2017 in participating states.

OUTCOME MEASURES

Statistical reliability, defined as the ability to distinguish true performance differences across hospitals relative to statistical noise. Reliability was assessed separately for 90-day inpatient costs (standardized across years to 2019 dollars), overall complications, and serious complication rates.

METHODS

Statistical reliability was measured as the amount of variation between hospitals relative to the total amount of variation for each measure. Total variation includes both between-hospital variation ("signal") and within-hospital variation ("statistical noise"). Thus, reliability equals signal over (signal plus noise) and ranges from 0 to 1. To adjust for differences in patient-level risk and procedural characteristics, hierarchical linear and logistic regression models were created for the cost and complication outcomes. Random hospital intercepts were used to assess between-hospital variation. We evaluated the reliability of each measure by study year and examined the number of hospitals meeting different thresholds of reliability by year.

RESULTS

We included a total of 66,571 elective lumbar fusion surgeries for spondylolisthesis performed at 244 hospitals during the study period. The mean 90-day hospital cost was $30,827 (2019 dollars). 12.0% of patients experienced a complication within 90 days of surgery, including 7.8% who had a serious complication. The median reliability of 90-day cost ranged from 0.97to 0.99 across study years, and there was a narrow distribution of reliability values. By comparison, the median reliability for the overall complication metric ranged from 0.22 to 0.44, and the reliability of the serious complication measure ranged from 0.30 to 0.49 across the study years. At least 96% of hospitals had high (> 0.7) reliability for cost in any year, whereas only 0-9% and 0-11% of hospitals reached this cutoff for the overall and serious complication rate in any year, respectively. By comparison, 10%-69% of hospitals per year achieved a more moderate threshold of 0.4 reliability for overall complications, compared to 21%-80% of hospitals who achieved this lower reliability threshold for serious complications.

CONCLUSIONS

90-day inpatient costs are highly reliable for assessing variation across hospitals, whereas overall and serious complications are only moderately reliable for profiling performance. These results support the viability of emerging bundled payment programs that assume true differences in costs of care exist across hospitals.

Clinical outcome following decompression and short or long instrumented fusion in lumbar degenerative spinal stenosis. A prospective case-control analysis

OBJECTIVES

There is limited data on the direct clinical comparison between short and long fusion following surgery for lumbar spinal stenosis. The hypothesis that regardless their baseline characteristics and morbidity, clinical outcome is similar in patients with lumbar stenosis treated with decompression plus posterior instrumented fusion in one or two versus three to five levels was tested.

METHODS

Subjects were divided into Group A and Group B corresponding to stenotic pathology and instrumented fusion in one or two levels and three to five levels, respectively. Primary outcome measures at one year were the change in SF-36 physical component (PCS) and Oswestry Disability Index (ODI). Secondary outcome measures included the EuroQol-5D (EQ-5D), the Visual Analog Scale (VAS), the mental component (MCS) of SF-36 scale and the Zung Self-Rating Depression Scale.

RESULTS

Seventy seven (77) patients were included (Group A, n = 42; Group B, n = 35). Patients in Group B were older, surgery lasted longer and intraoperative blood loss was greater than patients in Group A (p < 0.05). A significant clinical improvement was noted in both Groups on all scales (p < 0.01). Clinical outcome at one year was equally favorable in both Groups (p > 0.05). The evaluation of depression for Group A showed a significant improvement at one year (p = 0.02) compared to the preoperative status.

CONCLUSIONS

Older individuals are more likely to have multilevel stenosis and more co-morbidities and they were associated with longer instrumentation. However, complications are similar and clinical outcome is equally favorable compared to short instrumented fusion for fewer levels of disease.

Stable Low-Grade Degenerative Spondylolisthesis Does Not Compromise Clinical Outcome of Minimally Invasive Tubular Decompression in Patients with Spinal Stenosis

Background and Objectives: In recent literature, the routine addition of arthrodesis to decompression for lumbar spinal stenosis (LSS) with concomitant stable low-grade degenerative spondylolisthesis remains controversial. The purpose of this study is to compare the clinical outcome, complication and re-operation rates following minimally invasive (MIS) tubular decompression without arthrodesis in patients suffering from LSS with or without concomitant stable low-grade degenerative spondylolisthesis. Materials and Methods: This study is a retrospective review of prospectively collected data. Ninety-six consecutive patients who underwent elective MIS lumbar decompression with a mean follow-up of 27.5 months were included in the study. The spondylolisthesis (S) group comprised 53 patients who suffered from LSS with stable degenerative spondylolisthesis, and the control (N) group included 43 patients suffering from LSS without spondylolisthesis. Outcome measures included complications and revision surgery rates. Pre- and post-operative visual analog scale (VAS) for both back and leg pain was analyzed, and the Oswestry Disability Index (ODI) was used to evaluate functional outcome. Results: The two groups were comparable in most demographic and preoperative variables. VAS for back and leg pain improved significantly following surgery in both groups. Both groups showed significant improvement in their ODI scores, at one and two years postoperatively. The average length of hospital stay was significantly higher in patients with spondylolisthesis (p-value< 0.01). There was no significant difference between the groups in terms of post-operative complications rates or re-operation rates. Conclusions: Our results indicate that MIS tubular decompression may be an effective and safe procedure for patients suffering from LSS, with or without degenerative stable spondylolisthesis.

Classifying Patients Operated for Spondylolisthesis: A K-Means Clustering Analysis of Clinical Presentation Phenotypes

BACKGROUND

Trials of lumbar spondylolisthesis are difficult to compare because of the heterogeneity in the populations studied.

OBJECTIVE

To define patterns of clinical presentation.

METHODS

This is a study of the prospective Quality Outcomes Database spondylolisthesis registry, including patients who underwent single-segment surgery for grade 1 degenerative lumbar spondylolisthesis. Twenty-four-month patient-reported outcomes (PROs) were collected. A k-means clustering analysis-an unsupervised machine learning algorithm-was used to identify clinical presentation phenotypes.

RESULTS

Overall, 608 patients were identified, of which 507 (83.4%) had 24-mo follow-up. Clustering revealed 2 distinct cohorts. Cluster 1 (high disease burden) was younger, had higher body mass index (BMI) and American Society of Anesthesiologist (ASA) grades, and globally worse baseline PROs. Cluster 2 (intermediate disease burden) was older and had lower BMI and ASA grades, and intermediate baseline PROs. Baseline radiographic parameters were similar (P > .05). Both clusters improved clinically (P < .001 all 24-mo PROs). In multivariable adjusted analyses, mean 24-mo Oswestry Disability Index (ODI), Numeric Rating Scale Back Pain (NRS-BP), Numeric Rating Scale Leg Pain, and EuroQol-5D (EQ-5D) were markedly worse for the high-disease-burden cluster (adjusted-P < .001). However, the high-disease-burden cluster demonstrated greater 24-mo improvements for ODI, NRS-BP, and EQ-5D (adjusted-P < .05) and a higher proportion reaching ODI minimal clinically important difference (MCID) (adjusted-P = .001). High-disease-burden cluster had lower satisfaction (adjusted-P = .02).

CONCLUSION

We define 2 distinct phenotypes-those with high vs intermediate disease burden-operated for lumbar spondylolisthesis. Those with high disease burden were less satisfied, had a lower quality of life, and more disability, more back pain, and more leg pain than those with intermediate disease burden, but had greater magnitudes of improvement in disability, back pain, quality of life, and more often reached ODI MCID.

Improving effect of microendoscopic decompression surgery on low back pain in patients with lumbar spinal stenosis and predictive factors of postoperative residual low back pain: a single-center retrospective study

BACKGROUND

Although there are reports on the effectiveness of microendoscopic laminotomy using a spinal endoscope as decompression surgery for lumbar spinal stenosis, predicting the improvement of low back pain (LBP) still poses a challenge, and no clear index has been established. This study aimed to investigate whether microendoscopic laminotomy for lumbar spinal stenosis improves low back pain and determine the preoperative predictors of residual LBP.

METHODS

In this single-center retrospective study, we examined 202 consecutive patients who underwent microendoscopic laminotomy for lumbar spinal stenosis with a preoperative visual analog scale (VAS) score for LBP of ≥40 mm. The lumbar spine Japanese Orthopaedic Association (JOA), and VAS scores for LBP, leg pain (LP), and leg numbness (LN) were examined before and at 1 year after surgery. Patients with a 1-year postoperative LBP-VAS of ≥25 mm composed the residual LBP group. The preoperative predictive factors associated with postoperative residual LBP were analyzed.

RESULTS

JOA scores improved from 14.1 preoperatively to 20.2 postoperatively (p < 0.001), LBP-VAS improved from 66.7 to 29.7 mm (p < 0.001), LP-VAS improved from 63.8 to 31.2 mm (p < 0.001), and LN-VAS improved from 63.3 to 34.2 mm (p < 0.001). Ninety-eight patients (48.5%) had a postoperative LBP-VAS of ≥25 mm. Multiple logistic regression analysis revealed that Modic type 1 change (odds ratio [OR], 5.61; 95% confidence interval [CI], 1.68-18.68; p = 0.005), preoperative VAS for LBP ≥ 70 mm (OR, 2.19; 95% CI, 1.17-4.08; p = 0.014), and female sex (OR, 1.98; 95% CI, 1.09-3.89; p = 0.047) were preoperative predictors of residual LBP.

CONCLUSION

Microendoscopic decompression surgery had an ameliorating effect on LBP in lumbar spinal stenosis. Modic type 1 change, preoperative VAS for LBP, and female sex were predictors of postoperative residual LBP, which may be a useful index for surgical procedure selection.

Management and outcome of spinal implant-associated surgical site infections in patients with posterior instrumentation: analysis of 176 cases

PURPOSE

The management of implant-associated surgical site infections (SSI) in patients with posterior instrumentation is challenging. Evidence regarding the most appropriate treatment and the need for removal of implants is equivocal. We sought to evaluate the management and outcome of such patients at our institution.

METHODS

We searched our prospectively documented databases for eligible patients with posterior spinal instrumentation, excluding the cervical spine (January 2008-June 2018). Patient files were reviewed, demographic data and treatment details were recorded. Patient-reported outcome (PRO) was assessed with the Core Outcome Measures Index (COMI) preoperatively and postoperatively at 3 and 12 months.

RESULTS

A total of 170 patients underwent 210 revisions for 176 SSIs. Two-thirds presented within four weeks (105/176, 59.7%, median 22.5d, 7d-11.1y). The most common pathogens were Staphylococcus aureus (n = 79/210, 37.6%) and Staphylococcus epidermidis (n = 56/210, 26.7%). Debridement and implant retention was performed in 135/210 (64.3%) revisions and partial replacement in 62/210 (29.5%). In 28/176 SSI (15.9%), persistent infection required multiple revisions (≤ 4). Surgery was followed by intravenous and oral antimicrobial treatment (10-12w). In 139/176 SSIs (79%) with ≥ 1y follow-up, infection was cured in 115/139 (82.7%); relapse occurred in 9 (relapse rate: 5.1%). Two patients (1.4%) died. COMI decreased significantly (8.2 ± 1.5 vs. 4.8 ± 2.9, p < 0.0001) over 12 months. 72.7% of patients were (very) satisfied with their care.

CONCLUSION

Patients with SSI after posterior (thoraco-)lumbo(-sacral) instrumentation can be successfully treated in most cases with surgical and specific antibiotic treatment. An interdisciplinary approach is recommended. Loose implants should be replaced. In some cases, multiple revisions may be necessary. Patient outcomes were satisfactory.

Relationship between facet joint opening on CT and facet joint effusion on MRI in patients with lumbar spinal stenosis: analysis of a less invasive decompression procedure

OBJECTIVE

Both facet joint opening (FJO) on CT and facet joint effusion (FJE) on MRI are reportedly indicators of segmental instability in the lumbar facet joints of patients with lumbar spinal stenosis (LSS). However, no study has investigated both parameters simultaneously. Therefore, the association between these findings and which parameter is better for predicting clinical outcomes after surgical treatment remains unclear. The purpose of this study was to investigate the relationship between FJO and FJE in patients who underwent less invasive decompression procedures for LSS and to investigate the impact of these findings on clinical outcomes.

METHODS

This study included 1465 lumbar levels (L1-2 to L5-S1) in 293 patients who underwent less invasive surgery for LSS and had ≥ 5 years of follow-up. FJO was defined as joint space widening ≥ 2 mm on preoperative axial CT images. FJE was defined as fluid effusion in the facet joint on preoperative axial T2-weighted MR images. The characteristics and distributions of FJO and FJE were investigated with other preoperative radiological findings. The association between need for further surgery and FJO/FJE was analyzed according to intervertebral level.

RESULTS

FJO was observed at 402 levels (27%), and FJE was found at 306 levels (21%). The correspondence rate between FJO and FJE was 70% (kappa 0.195, p < 0.01). One hundred thirty-seven levels (9%) had both FJO and FJE. Levels with both FJO and FJE more commonly had lateral olisthesis, lateral wedging, and axial intervertebral rotation than other levels (p < 0.001). Levels with both FJO and FJE were more likely than other levels to need further surgery (OR 2.42, p = 0.027).

CONCLUSIONS

The correspondence rate between FJO and FJE was not high. However, multivariate analysis showed that levels with both FJO and FJE had a higher risk of requiring further surgery than those with other radiological findings, such as lateral olisthesis, lateral wedging, and axial intervertebral rotation. Patients with levels with both FJO and FJE need careful long-term follow-up after undergoing a less invasive decompression procedure.

Revision surgery following minimally invasive decompression for lumbar spinal stenosis with and without stable degenerative spondylolisthesis: a 5- to 15-year reoperation survival analysis

OBJECTIVE

Minimally invasive decompression (MID) is an effective procedure for lumbar spinal stenosis (LSS). Long-term follow-up data on reoperation rates are lacking. The objective of this retrospective cohort study was to evaluate reoperation rates in patients with LSS who underwent MID, stratified for degenerative lumbar spondylolisthesis (DLS), with a follow-up between 5 and 15 years.

METHODS

All consecutive patients with LSS who underwent MID between 2002 and 2011 were included. All patients had neurogenic claudication from central and/or lateral recess stenosis, without or with up to 25% of slippage (grade I spondylolisthesis), and no obvious dynamic instability on imaging (increase in spondylolisthesis by ≥ 5 mm demonstrated on supine-to-standing or flexion-extension imaging). Reoperation rates defined as any operation on the same or adjacent level were assessed. Revision decompression alone was considered if the aforementioned clinical and radiographic criteria were met; otherwise, patients underwent a minimally invasive posterior fusion.

RESULTS

A total of 246 patients (mean age 66 years) were included. Preoperative spondylolisthesis was present in 56.9%. The mean follow-up period was 8.2 years (range 5.0-14.9 years). The reoperation rates in patients with and without spondylolisthesis were 15.7% and 15.1%, respectively; fusion was required in 7.1% and 7.5%, with no significant difference (redecompression only, p = 0.954; fusion, p = 0.546). For decompression only, the mean times to reoperation were 3.9 years (95% CI 1.8-6.0 years) for patients with DLS and 2.8 years (95% CI 1.3-4.2 years) for patients without DLS; for fusion, the mean times to reoperation were 3.1 years (95% CI 1.0-5.3 years) and 3.1 years (95% CI 1.1-5.1 years), respectively.

CONCLUSIONS

In highly selected patients with stable DLS and leg-dominant pain from central or lateral recess stenosis, the long-term reoperation rate is similar between DLS and non-DLS patients undergoing MIS decompression.

A review of trauma and orthopaedic randomised clinical trials published in high-impact general medical journals

Introduction

The recent past has seen a significant increase in the number of trauma and orthopaedic randomised clinical trials published in “the big five” general medical journals. The quality of this research has, however, not yet been established.

Methods

We therefore set out to critically appraise the quality of available literature over a 10-year period (April 2010–April 2020) through a systematic search of these 5 high-impact general medical journals (JAMA, NEJM, BMJ, Lancet and Annals). A standardised data extraction proforma was utilised to gather information regarding: trial design, sample size calculation, results, study quality and pragmatism. Quality assessment was performed using the Cochrane Risk of Bias 2 tool and the modified Delphi list. Study pragmatism was assessed using the PRECIS-2 tool.

Results

A total of 25 studies were eligible for inclusion. Over half of the included trials did not meet their sample size calculation for the primary outcome, with a similar proportion of these studies at risk of type II error for their non-significant results. There was a high degree of pragmatism according to PRECIS-2. Non-significant studies had greater pragmatism that those with statistically significant results (p < 0.001). Only 56% studies provided adequate justification for the minimum clinically important difference (MCID) in the population assessed. Overall, very few studies were deemed high quality/low risk of bias.

Conclusions

These findings highlight that there are some important methodological concerns present within the current evidence base of RCTs published in high-impact medical journals. Potential strategies that may improve future trial design are highlighted.

Level of evidence

Level 1.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00590-021-03137-3.

Decompression of Lumbar Central Spinal Canal Stenosis Following Minimally Invasive Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

This was a retrospective clinical series.

OBJECTIVE

The objective of this study was to evaluate radiologic changes in central spinal canal dimensions following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) with placement of a static or an expandable interbody device.

SUMMARY OF BACKGROUND DATA

MIS-TLIF is used to treat lumbar degenerative diseases and low-grade spondylolisthesis. MIS-TLIF enables direct and indirect decompression of lumbar spinal stenosis, with patients experiencing relief from radiculopathy and neurogenic claudication. However, the effects of MIS-TLIF on the central spinal canal are not well-characterized.

MATERIALS AND METHODS

We identified patients who underwent MIS-TLIF for degenerative lumbar spondylolisthesis and concurrent moderate to severe spinal stenosis. We selected patients who had both preoperative and postoperative magnetic resonance imaging (MRI) and upright lateral radiographs of the lumbar spine. Measurements on axial T2-weighted MRI scans include anteroposterior and transverse dimensions of the dural sac and osseous spinal canal. Measurements on radiographs include disk height, neural foraminal height, segmental lordosis, and spondylolisthesis. We made pairwise comparisons between each of the central canal dimensions and lumbar sagittal segmental radiologic outcome measures relative to their corresponding preoperative values. Correlation coefficients were used to quantify the association between changes in lumbar sagittal segmental parameters relative to changes in radiologic outcomes of central canal dimensions. Statistical analysis was performed for "all patients" and further stratified by interbody device subgroups (static and expandable).

RESULTS

Fifty-one patients (age 60.4 y, 68.6% female) who underwent MIS-TLIF at 55 levels (65.5% at L4-L5) were included in the analysis. Expandable interbody devices were used in 45/55 (81.8%) levels. Mean duration from surgery to postoperative MRI scan was 16.5 months (SD 11.9). MIS-TLIF was associated with significant improvements in dural sac dimensions (anteroposterior +0.31 cm, transverse +0.38 cm) and osseous spinal canal dimensions (anteroposterior +0.16 cm, transverse +0.32 cm). Sagittal lumbar segmental parameters of disk height (+0.56 cm), neural foraminal height (+0.35 cm), segmental lordosis (+4.26 degrees), and spondylolisthesis (-7.5%) were also improved following MIS-TLIF. We did not find meaningful associations between the changes in central canal dimensions relative to the corresponding changes in any of the sagittal lumbar segmental parameters. Stratified analysis by interbody device type (static and expandable) revealed similar within-group changes as in the overall cohort and minimal between-group differences.

CONCLUSIONS

MIS-TLIF is associated with radiologic decompression of neural foraminal and central spinal canal stenosis. The mechanism for neural foraminal and central canal decompression is likely driven by a combination of direct and indirect corrective techniques.

Application of an index derived from the area under a neutrophil curve as a predictor of surgical site infection after spinal surgery

Background

Patients with prolonged and intense neutrophilia after spinal surgery are at high risk of developing surgical site infection (SSI). To date, there is no standard method for the objective assessment of the intensity and duration of neutrophilia. Thus, this retrospective observational study aimed to test a new index (I-index), developed by combining the duration and intensity of neutrophilia, as a predictor of SSI.

Methods

I-index was calculated based on the postoperative neutrophil percentage. A total of 17 patients with SSI were enrolled as cases, and 51 patients without SSI were selected as controls. The groups were matched at a ratio of 1:3 by age, sex, and surgery type. The differences in the I-index were compared between the groups. Moreover, we checked the cumulative I-index (c-I-index), which we defined as the area under the neutrophil curve from postoperative day 1 until the first clinical manifestation of SSI in each case. Furthermore, a cutoff for SSI was defined using the receiver operating characteristic curve.

Results

The median I-index-7, I-index-14, and c-I-index were significantly higher in the SSI group than those in the control group. For a cutoff point of 42.1 of the I-index-7, the sensitivity and specificity were 0.706 and 0.882, respectively. For a cutoff point of 45.95 of the I-index-14, the sensitivity and specificity were 0.824 and 0.804, respectively. For a cutoff point of 45.95 of the c-I-index, the sensitivity and specificity were 0.824 and 0.804, respectively.

Conclusion

We devised a new indicator of infection, i.e., the I-Index and c-I-index, and confirmed its usefulness in predicting SSI.

Clinical Outcomes of Minimally Invasive Posterior Decompression for Lumbar Spinal Stenosis with Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To compare the clinical outcomes 5 years after minimally invasive posterior decompression for lumber spinal stenosis (LSS) between patients with and without degenerative spondylolisthesis (DS).

SUMMARY OF BACKGROUND DATA

Indications for surgical procedures for patients with LSS and DS are still under investigation. Since minimally invasive surgery does not affect most anatomical structures, preoperative DS may not negatively affect the clinical outcomes of minimally invasive posterior decompression.

METHODS

Overall, 198 patients with LSS who underwent microendoscopic or microscopic decompression and were followed up for more than 5 years postoperatively were included in the present study. Patients who showed a segmental kyphosis >5° at the surgical level during flexion were treated with fusion surgery. However, other patients, including those with DS, were treated with posterior decompression. The patients were divided into two groups: the DS group included 82 patients with >3-mm slip and the non-DS group included 112 patients with ≤3-mm slip or without slip. A mixed-effects model adjusted for age and sex was used to compare the improvements in the visual analog scale score for low-back pain and the Japanese Orthopaedic Association score of the two groups. For subgroup analysis (n = 53), the changes in the preoperative physical component summary and the mental component summary of Short Form-36 of the two groups at 5 years after surgery were evaluated.

RESULTS

There was no significant difference in the improvement of preoperative low-back pain visual analog scale score and Japanese Orthopaedic Association score 5 years after surgery between the two groups. Subgroup analysis showed no significant difference between the two groups in the improvement of preoperative physical component summary and mental component summary 5 years after surgery.

CONCLUSION

After carefully eliminating patients with segmental instability, DS did not affect the clinical outcomes of minimally invasive decompression surgery.Level of Evidence: 3.

Pain Control Affects the Radiographic Diagnosis of Segmental Instability in Patients with Degenerative Lumbar Spondylolisthesis

BACKGROUND

Diagnosing intervertebral instability is crucial for the treatment of degenerative lumbar spondylolisthesis (DLS). Disabling back pain will reduce spinal mobility which leads to an underestimate of the incidence of intervertebral instability. We hypothesized that adequate analgesia could alter the flexion/extension exam performance, and thus increase the diagnostic accuracy of segmental instability.

MATERIALS AND METHODS

One hundred patients with low-grade DLS were prospectively enrolled in the before-after cohort study. Standing lateral flexion/extension radiographs of lumbar spines were examined and analyzed before and after intramuscular injections of 30 mg ketorolac.

RESULTS

Pain score decreased significantly after analgesic injections (p < 0.001). Dynamic slip (DS), dynamic segmental angle (DA), dynamic lumbar lordosis, and slip percentage (SP) were significantly increased after pain reduction (all p < 0.001). According to the diagnostic criteria for segmental instability (DS > 4.5 mm, DA > 15°, or SP > 15%), there were 4%, 4%, and 0.7% of total motion segments fulfilling the criteria which markedly increased to 42%, 32%, and 16.7% after analgesia was administered. The incidence of instability also increased from 6% to 38% after analgesia.

CONCLUSIONS

The diagnosis rate of intervertebral instability is commonly underestimated in the presence of low back pain. This short-term pain relief facilitates reliable functional imaging adding to the diagnosis of intervertebral instability.

Precise laminae segmentation based on neural network for robot-assisted decompressive laminectomy

BACKGROUND AND OBJECTIVE

The decompressive laminectomy is one of the most common operations to treat lumbar spinal stenosis by removing the laminae above the spinal nerve. Recently, an increasing number of robots are deployed during the surgical process to reduce the burden on surgeons and to reduce complications. However, for the robot-assisted decompressive laminectomy, an accurate 3D model of laminae from a CT image is highly desired. The purpose of this paper is to precisely segment the laminae with fewer calculations.

METHODS

We propose a two-stage neural network SegRe-Net. In the first stage, the entire intraoperative CT image is inputted to acquire the coarse segmentation of vertebrae with low resolution and the probability map of the laminar centers. The second stage is trained to refine the segmentation of laminae.

RESULTS

Three public available datasets were used to train and validate the models. The experimental results demonstrated the effectiveness of the proposed network on laminar segmentation with an average Dice coefficient of 96.38% and an average symmetric surface distance of 0.097 mm.

CONCLUSION

The proposed two-stage network can achieve better results than those baseline models in the laminae segmentation task with less calculation amount and learnable parameters. Our methods improve the accuracy of laminar models and reduce the image processing time. It can be used to provide a more precise planning trajectory and may promote the clinical application for the robot-assisted decompression laminectomy surgery.

Comparison of Prone Transpsoas and Standard Lateral Lumbar Interbody Fusion Surgery for Degenerative Lumbar Spine Disease: A Retrospective Radiographic Propensity Score-Matched Analysis

BACKGROUND

Prone transpsoas lateral lumbar interbody fusion (PTP-LLIF) is a recently introduced modification to standard LLIF. To date, no study has compared the radiographic outcomes of standard LLIF and PTP-LLIF. We performed a radiographic parameter-based propensity score-matched analysis to compare postoperative clinical and radiographic outcomes between PTP-LLIF and standard LLIF for degenerative lumbar spine disease.

METHODS

A total of 30 consecutive patients met the inclusion criteria. The preoperative standing scoliosis radiographs were retrospectively reviewed for global and segmental sagittal alignment. Propensity score matching was calculated using the baseline radiographic parameters. One-to-one matching of patients who had undergone PTP-LLIF with those who had a similar propensity score but had undergone standard LLIF was performed to compare the radiographic (primary) and clinical (secondary) outcomes.

RESULTS

Propensity score matching resulted in 10 pairs of PTP-LLIF and standard LLIF patients. The PTP-LLIF group had had significantly better improvement in lumbar lordosis (P = 0.047). The difference in the improvement in pelvic incidence minus lumbar lordosis mismatch approached statistical significance for the PTP-LLIF group (P = 0.05). This led to better improvement in the short-form 12-item physical score (P = 0.03) and Oswestry disability index (P = 0.1) in the PTP-LLIF group. No significant differences were found between the 2 groups in the other clinical and radiographic outcomes. The PTP-LLIF group had a shorter operative time (P = 0.4) and hospital stay (P = 0.1), without a statistically difference, and shorter radiation exposure time (P = 0.5). The standard LLIF group had experienced less intraoperative bleeding, without a statistically significant difference (P = 0.3). The mean follow-up time was 10.2 ± 5.2 months in the PTP-LLIF group and 30.9 ± 17.2 months in the standard LLIF group (P < 0.05).

CONCLUSIONS

The PTP-LLIF group showed significantly better improvement in lumbar lordosis and short-form 12-item physical score.

Classification and Reliability of Lumbar Facet Cysts Grading Scales

BACKGROUND

The presence of symptomatic lumbar facet cysts has been associated with segmental instability. Given this association, decompression versus decompression with fusion is a frequently debated topic. Multiple grading scales have been devised to identify patients at high risk for development of cyst recurrence; however, there exists no external evaluation of these scales.

METHODS

A retrospective review of 54 patients undergoing initial treatment for lumbar synovial cysts at a single institution over the past 12 years was conducted. Surgical treatment consisted of decompression with cystectomy without fusion. Patients were assessed and classified according to the NeuroSpine Surgery Research Group (NSURG) and Rosenstock Classification systems. Five neurosurgeons reviewed the preoperative magnetic resonance images, and results were classified. Interrater reliability was assessed using both Gwet's AC1 coefficient and Krippendorff's alpha. A 1-way analysis of variance was used to evaluate predictive ability of both classification systems.

RESULTS

In total, of the 54 patients who underwent decompression, 7 had cyst recurrence. Overall cyst recurrence was most common in NSURG grade 2 cysts (3/12, 25%) followed by grade 1 cysts (4/27, 14.8%). Of the NSURG grade 3 and 4 patients, none had cyst recurrence. In the Rosenstock grades the most common recurrence was in grade 3 cysts (1/4, 25%) followed by grade 1 cysts (5/26, 19.2%). Interrater reliability demonstrated good reproducibility on Gwet's AC1 and Krippendorff's alpha on both grading scales. Neither score was predictive of cyst recurrence (P > 0.05).

CONCLUSIONS

The Rosenstock and NeuroSpine scores demonstrate good overall interrater reliability but are inconsistent in their ability to predict recurrence of lumbar facet cysts.

Decompression alone versus decompression and instrumented fusion for the treatment of isthmic spondylolisthesis: a randomized controlled trial

OBJECTIVE

The most advocated surgical technique to treat symptoms of isthmic spondylolisthesis is decompression with instrumented fusion. A less-invasive classical approach has also been reported, which consists of decompression only. In this study the authors compared the clinical outcomes of decompression only with those of decompression with instrumented fusion in patients with isthmic spondylolisthesis.

METHODS

Eighty-four patients with lumbar radiculopathy or neurogenic claudication secondary to low-grade isthmic spondylolisthesis were randomly assigned to decompression only (n = 43) or decompression with instrumented fusion (n = 41). Primary outcome parameters were scores on the Roland Disability Questionnaire (RDQ), separate visual analog scales (VASs) for back pain and leg pain, and patient report of perceived recovery at 12-week and 2-year follow-ups. The proportion of reoperations was scored as a secondary outcome measure. Repeated measures ANOVA according to the intention-to-treat principle was performed.

RESULTS

Decompression alone did not show superiority in terms of disability scores at 12-week follow-up (p = 0.32, 95% CI -4.02 to 1.34), nor in any other outcome measure. At 2-year follow-up, RDQ disability scores improved more in the fusion group (10.3, 95% CI 3.9-8.2, vs 6.0, 95% CI 8.2-12.4; p = 0.006, 95% CI -7.3 to -1.3). Likewise, back pain decreased more in the fusion group (difference: -18.3 mm, CI -32.1 to -4.4, p = 0.01) on a 100-mm VAS scale, and a higher proportion of patients perceived recovery as showing "good results" (44% vs 74%, p = 0.01). Cumulative probabilities for reoperation were 47% in the decompression and 13% in the fusion group (p < 0.001) at the 2-year follow-up.

CONCLUSIONS

In patients with isthmic spondylolisthesis, decompression with instrumented fusion resulted in comparable short-term results, significantly better long-term outcomes, and fewer reoperations than decompression alone. Decompression with instrumented fusion is a superior surgical technique that should in general be offered as a first treatment option for isthmic spondylolisthesis, but not for degenerative spondylolisthesis, which has a different etiology.

How Preoperative Motor Weakness Affects the Extent of Recovery After Elective Spine Surgery in Patients with Degenerative Lumbar Spinal Stenosis

STUDY DESIGN

Retrospective review.

OBJECTIVE

This study sought to determine how baseline motor weakness (MW) affects elective spine surgery in patients with degenerative lumbar spinal stenosis (LSS).

SUMMARY OF BACKGROUND DATA

Favorable clinical outcomes have been described for elective spine surgery in patients with LSS. However, the way preoperative MW affects the patient's health-related quality of life (HRQoL) after surgery is not well understood.

METHODS

A retrospective review of prospectively collected data from 305 surgically treated patients with LSS who had 2-year follow-up was performed (age 71 ± 9 yrs, male 62%). Demographic, radiographic, and clinical outcomes were analyzed at baseline and at 1-year, 2-year, and 3-year postoperation. The Japanese Orthopedic Association Back Pain Evaluation Questionnaire was used to assess the HRQoLs. The HRQoLs were compared between those with or without preop MW. Adjusted multivariate logistic regression analyses were performed to determine whether MW affected HRQoLs.

RESULTS

One hundred sixteen patients (38%) were categorized as MW+. The patient background including age, sex, presence of degenerative spondylolisthesis, type of surgery, and presence of neurological claudication were similar between the two groups. However, the 1-, 2-, and 3-year postoperative visual analogue scale of back pain, leg pain, leg numbness, the Japanese Orthopedic Association Back Pain Evaluation Questionnaire lumbar function, social life, mental health, and walking ability were all inferior in the MW+ group, whereas a similar percentage of patients achieved a minimum clinically important difference in all subdomains at 3 years. The adjusted multivariate logistic regression analyses showed that having ≥2 muscles with MW, and severity of MW (manual motor test grade) were independent risk factors for both difficulty climbing stairs and walking >15 minutes. (muscles with MW≥2; stair climbing: OR 6.4[2.3-17.4], walking: OR 3.2[1.4-7.3], severity of MW; stair climbing: OR 2.5[1.4-4.4], walking: OR 2.2[1.3-3.7]).

CONCLUSION

The patients with baseline MW had inferior HRQoL for up to 3 years compared with that of those without MW; however, the amount of improvement in HRQoL was comparable. Timely follow-up is important to find out the deterioration of motor function.Level of Evidence: 4.

Independent Predictors of Revision Lumbar Fusion Outcomes and the Impact of Spine Surgeon Variability: Does It Matter Whether the Primary Surgeon Revises?

BACKGROUND

There is a paucity of information regarding treatment strategies and variables affecting outcomes of revision lumbar fusions.

OBJECTIVE

To evaluate the influence of primary vs different surgeon on functional outcomes of revisions.

METHODS

All elective lumbar fusion revisions, March 2018 to August 2019, were retrospectively categorized as performed by the same or different surgeon who performed the primary surgery. Oswestry Disability Index (ODI) and clinical variables were collected. Multiple logistic regression identified multivariable-adjusted odds ratio (OR) of independent variables analyzed.

RESULTS

Of the 130 cases, 117 (90%) had complete data. There was a slight difference in age in the same (median: 59; interquartile range [IQR], 54-66) and different surgeon (median: 67; IQR, 56-72) groups (P = .02); all other demographic variables were not significantly different (P > .05). Revision surgery with a different surgeon had an ODI improvement (median: 8; IQR, 2-14) greater than revisions performed by the same surgeon (median: 1.5; IQR, -3 to 10) (P < .01). Revisions who achieved minimum clinically important difference (MCID) performed by different surgeon (59.7%) were also significantly greater than the ones performed by the same surgeon (40%) (P = .042). Multivariate analysis demonstrated that a different surgeon revising (OR, 2.37; [CI]: 1.007-5.575, P = .04) was an independent predictor of MCID achievement, each additional 2 years beyond the last surgery conferred a 2.38 ([CI]: 1.36-4.14, P < .01) times greater odds of MCID achievement, and the anterior lumbar interbody fusion approach decreased the chance of achieving MCID (OR, 0.19; [CI]: 0.04-0.861, P = .03).

CONCLUSION

All revision lumbar spinal fusion approaches may not achieve the same outcomes. This analysis suggests that revision surgeries may have better outcomes when performed by a different surgeon.

Clinical outcomes in revision lumbar spine fusions: an observational cohort study

OBJECTIVE

The authors compared primary lumbar spine fusions with revision fusions by using patient Oswestry Disability Index (ODI) scores to evaluate the impact of the North American Spine Society (NASS) evidence-based medicine (EBM) lumbar fusion indications on patient-reported outcome measures of revision surgeries.

METHODS

This study was a retrospective analysis of a prospective observational cohort of patients who underwent elective lumbar fusion between January 2018 and December 2019 at a single quaternary spine surgery service and had a minimum of 6 months of follow-up. A prospective quality improvement database was constructed that included the data from all elective lumbar spine surgeries, which were categorized prospectively as primary or revision surgeries and EBM-concordant or EBM-discordant revision surgeries based on the NASS coverage EBM policy. In total, 309 patients who met the inclusion criteria were included in the study. The ODIs of all groups (primary, revision, revision EBM concordant, and revision EBM discordant) were statistically compared. Differences in frequencies between cohorts were evaluated using chi-square and Fisher's exact tests. The unpaired 2-tailed Student t-test and the Mann-Whitney U-test for nonparametric data were used to compare continuous variables. Logistic regression was performed to determine the associations between independent variables (surgery status and NASS criteria indications) and functional outcomes.

RESULTS

Primary lumbar fusions were significantly associated with improved functional outcomes compared with revisions, as evidenced by ODI scores (OR 1.85, 95% CI 1.16-2.95 to achieve a minimal clinically important difference, p = 0.01). The percentage of patients whose functional status had declined at the 6-month postoperative evaluation was significantly higher in patients who had undergone a revision surgery than in those who underwent a primary surgery (23% vs 12.3%, respectively). An increase in ODI score, indicating worse clinical outcome after surgery, was greater in patients who underwent revision procedures (OR 2.14, 95% CI 1.17-3.91, p = 0.0014). Patients who underwent EBM-concordant revision surgery had significantly improved mean ODI scores compared with those who underwent EBM-discordant revision surgery (7.02 ± 5.57 vs -4.6 ± 6.54, p < 0.01).

CONCLUSIONS

The results of this prospective quality improvement program investigation illustrate that outcomes of primary lumbar fusions were superior to outcomes of revisions. However, revision procedures that met EBM guidelines were associated with greater improvements in ODI scores, which indicates that the use of defined EBM guideline criteria for reoperation can improve clinical outcomes of revision lumbar fusions.

Decompression with or without Fusion in Degenerative Lumbar Spondylolisthesis

BACKGROUND

In patients with lumbar spinal stenosis and degenerative spondylolisthesis, it is uncertain whether decompression surgery alone is noninferior to decompression with instrumented fusion.

METHODS

We conducted an open-label, multicenter, noninferiority trial involving patients with symptomatic lumbar stenosis that had not responded to conservative management and who had single-level spondylolisthesis of 3 mm or more. Patients were randomly assigned in a 1:1 ratio to undergo decompression surgery (decompression-alone group) or decompression surgery with instrumented fusion (fusion group). The primary outcome was a reduction of at least 30% in the score on the Oswestry Disability Index (ODI; range, 0 to 100, with higher scores indicating more impairment) during the 2 years after surgery, with a noninferiority margin of -15 percentage points. Secondary outcomes included the mean change in the ODI score as well as scores on the Zurich Claudication Questionnaire, leg and back pain, the duration of surgery and length of hospital stay, and reoperation within 2 years.

RESULTS

The mean age of patients was approximately 66 years. Approximately 75% of the patients had leg pain for more than a year, and more than 80% had back pain for more than a year. The mean change from baseline to 2 years in the ODI score was -20.6 in the decompression-alone group and -21.3 in the fusion group (mean difference, 0.7; 95% confidence interval [CI], -2.8 to 4.3). In the modified intention-to-treat analysis, 95 of 133 patients (71.4%) in the decompression-alone group and 94 of 129 patients (72.9%) in the fusion group had a reduction of at least 30% in the ODI score (difference, -1.4 percentage points; 95% CI, -12.2 to 9.4), showing the noninferiority of decompression alone. In the per-protocol analysis, 80 of 106 patients (75.5%) and 83 of 110 patients (75.5%), respectively, had a reduction of at least 30% in the ODI score (difference, 0.0 percentage points; 95% CI, -11.4 to 11.4), showing noninferiority. The results for the secondary outcomes were generally in the same direction as those for the primary outcome. Successful fusion was achieved with certainty in 86 of 100 patients (86.0%) who had imaging available at 2 years. Reoperation was performed in 15 of 120 patients (12.5%) in the decompression-alone group and in 11 of 121 patients (9.1%) in the fusion group.

CONCLUSIONS

In this trial involving patients who underwent surgery for degenerative lumbar spondylolisthesis, most of whom had symptoms for more than a year, decompression alone was noninferior to decompression with instrumented fusion over a period of 2 years. Reoperation occurred somewhat more often in the decompression-alone group than in the fusion group. (NORDSTEN-DS ClinicalTrials.gov number, NCT02051374.).

Comparing Investigation Between Bilateral Partial Laminectomy and Posterior Lumbar Interbody Fusion for Mild Degenerative Spondylolisthesis

STUDY DESIGN

A retrospective comparative study.

OBJECTIVE

The present study aims to compare the surgical outcomes between bilateral partial laminectomy (BPL) and posterior lumbar interbody fusion (PLIF) in patients with mild degree of slippage.

SUMMARY OF BACKGROUND DATA

To date, there have not been established surgical procedures for patients with mild degree of slippage. Moreover, sufficient studies that have compared surgical outcomes between BPL and PLIF are very few.

MATERIALS AND METHODS

In this retrospective study, the authors enrolled 202 consecutive patients with degenerative spondylolisthesis with slippage at L3 or L4 of >3% who underwent spine surgery between 2005 and 2015. Patients were grouped into those who underwent single-segment PLIF (n=106) and those who underwent BPL (n=51). To adjust for potential confounders, the inverse probability of treatment weighting based on the propensity score was used. Surgical outcomes were compared between the BPL and PLIF groups. The threshold age for the final recovery rate of >70% was evaluated using receiver operating characteristic curve analyses to assess the limit of age to achieve good outcomes. Patients who underwent reoperation in both groups were also evaluated.

RESULTS

Operation time and blood loss were significantly lower in the BPL group. The final recovery rate was similar between the groups without age stratification. The cutoff age to achieve a final recovery rate of >70% was 75 years in the PLIF group, and the final recovery rate was significantly higher in the PLIF group than in the BPL group in patients aged less than 75 years but not in patients aged 75 years or older. In addition, the reoperation rate was similar between groups, and all reoperations in the PLIF group were for adjacent segment disease.

CONCLUSIONS

BPL is one of the useful options in patients with mild degenerative spondylolisthesis, particularly in patients aged more than 75 years.

Management of degenerative spondylolisthesis: development of appropriate use criteria

BACKGROUND CONTEXT

Outcomes of treatment in care of patients with spinal disorders are directly related to patient selection and treatment indications. However, for many disorders, there is absence of consensus for precise indications. With the increasing emphasis on quality and value in spine care, it is essential that treatment recommendations and decisions are optimized.

PURPOSE

The purpose of the North American Spine Society Appropriate Use Criteria was to determine the appropriate (ie reasonable) multidisciplinary treatment recommendations for patients with degenerative spondylolisthesis across a spectrum of more common clinical scenarios.

STUDY DESIGN

A Modified Delphi process was used.

METHODS

The methodology was based on the Appropriate Use Criteria development process established by the Research AND Development Corporation. The topic of degenerative spondylolisthesis was selected by the committee, key modifiers determined, and consensus reached on standard definitions. A literature search and evidence analysis were completed by one work group simultaneously as scenarios were written, reviewed, and finalized by another work group. A separate multidisciplinary rating group was assembled. Based on the literature, provider experience, and group discussion, each scenario was scored on a nine-point scale on two separate occasions, once without discussion and then a second time following discussion based on the initial responses. The median rating for each scenario was then used to determine if indications were rarely appropriate (1 - 3), uncertain (4-6), or appropriate (7-9). Consensus was not mandatory.

RESULTS

There were 131 discrete scenarios. These addressed questions on bone grafting, imaging, mechanical instability, radiculopathy with or without neurological deficits, obesity, and yellow flags consisting of psychosocial and medical comorbidities. For most of these, appropriateness was established for physical therapy, injections, and various forms of surgical intervention. The diagnosis of spondylolisthesis should be determined by an upright x-ray. Scenarios pertaining to bone grafting suggested that patients should quit smoking prior to surgery, and that use of BMP should be reserved for patients who had risk factors for non-union. Across all clinical scenarios, physical therapy (PT) had an adjusted mean of 7.66, epidural steroid injections 5.76, and surgery 4.52. Physical therapy was appropriate in most scenarios, and most appropriate in patients with back pain and no neurological deficits. Epidural steroid injections were most appropriate in patients with radiculopathy. Surgery was generally more appropriate for patients with neurological deficits, higher disability scores, and dynamic spondylolisthesis. Mechanical back pain and presence of yellow flags tended to be less appropriate, and obesity in general had relatively little influence on decision making. Decompression alone was more strongly considered in the presence of static versus dynamic spondylolisthesis. On average, posterior fusion with or without interbody fusion was similarly appropriate, and generally more appropriate than stand-alone interbody fusion which was in turn more appropriate than interspinous spacers.

CONCLUSIONS

Multidisciplinary appropriate treatment criteria were generated based on the Research AND Development methodology. While there were consistent and significant differences between surgeons and non-surgeons, these differences were generally very small. This document provides comprehensive evidence-based recommendations for evaluation and treatment of degenerative spondylolisthesis. The document in its entirety will be found on the North American Spine Society website (https://www.spine.org/Research-Clinical-Care/Quality-Improvement/Appropriate-Use-Criteria).

Quality of life scores in patients with unruptured cerebral aneurysm: Prospective cohort study

BACKGROUND

Living with the diagnosis of an unruptured cerebral aneurysm can understandably cause distress to a patient. The goal of preventive treatment is to increase the number of years with good quality of life (QoL).

OBJECTIVE

This study aimed to measure the effect of unruptured intracranial aneurysm treatment on change in QoL scores measured by the SF36 and EQ-5D-5L.

METHODS

We prospectively collected SF36 and EQ-5D-5L survey data for patients with unruptured intracranial aneurysms at two time-points over 1 year between 2 treatment groups: observation and intervention (microsurgical and endovascular). Multivariable linear regression was used to examine treatment group differences in the mean change in scores from baseline to 1 year when adjusted for covariates.

RESULTS

92 patients were included in the observation group and 68 patients were included in the intervention group, for a total of 160 patients. The intervention group had lower SF36 total scores at baseline (p = 0.001). With multivariate linear regression models, the effect of treatment on mean change in SF36 total score from baseline to 1 year was not statistically significant (p = 0.4); similarly, there was no difference in mean change in EQ-5D-5L.

CONCLUSION

In this large prospective study, preventive aneurysm treatment was not associated with a significant change in QoL score at 1 year compared to observation as measured by the SF36 and EQ-5D-5L. Further studies are needed to explore the lower QoL scores in patients seeking treatment and its impact on management decision making.

Variation in surgical treatment of degenerative spondylolisthesis in Canada: surgeon assessment of stability and impact on treatment

INTRODUCTION

Controversy exists regarding the optimal surgical treatment of degenerative lumbar spondylolisthesis (DS). Not all DS patients are the same, and the degree to which inherent stability may dictate treatment is unknown. The purpose of this study was to determine the variability in surgical approach relative to surgeon classified stability. The secondary objective was to compare patient-reported outcomes (PROs) across different surgical techniques and grades of stability.

METHODS

Patients prospectively enrolled from eleven tertiary care institutions and followed from 2015 to 2019. The surgical technique was at the surgeon's discretion. Surgeons were asked to grade the degree of instability based on the degenerative spondylolisthesis instability classification system (DSIC). DSIC categorizes three different types (I-stable, II-potentially unstable, and III-unstable). One-year changes in PROs were compared between each group. Multivariable regression was used to identify any characteristics that explained variability in treatment.

RESULTS

There were 323 patients enrolled in this study. Surgeons' stability classification versus procedure [decompression alone (D)/decompression and posterolateral fusion (D-PL)/and decompression with posterior/transforaminal lumbar interbody fusion (D-PLIF/TLIF)] were as follows: type I (n = 91): D-41%/D-PL-13%/D-PLIF/TLIF-46%; type II (n = 175): D-23%/D-PL-17%/D-PLIF/TLIF-60%; and type III (n = 57):(D-0%/D-PL-14%/D-PLIF/TLIF-86%). Type I patients undergoing D-PL had some improvements in EQ-5D and NRS versus those undergoing D-PLIF/TLIF but otherwise there were no other significant differences between groups. Regression analysis demonstrated advanced age (OR = 1.06, CI 1.02-10.12) and type I (OR = 2.61, CI 1.17-5.81) were associated with receiving decompression surgery alone.

CONCLUSIONS

There exists considerable variation in surgical management of DS in Canada. Given similar PROs in two of the three groups, there is potential to tailor surgical intervention and improve resource utilization.

Alternatives to Traditional Pedicle Screws for Posterior Fixation of the Degenerative Lumbar Spine

BACKGROUND

Traditional pedicle screws are currently the gold standard to achieve stable 3-column fixation of the degenerative lumbar spine. However, there are cases in which pedicle screw fixation may not be ideal. Due to their starting point lateral to the pars interarticularis, pedicle screws require a relatively wide dissection along with a medialized trajectory directed toward the centrally located neural elements and prevertebral vasculature. In addition, low bone mineral density remains a major risk factor for pedicle screw loosening, pullout, and pseudarthrosis. The purpose of this article is to review the indications, advantages, disadvantages, and complications associated with posterior fixation techniques of the degenerative lumbar spine beyond the traditional pedicle screws.

METHODS

Comprehensive literature searches of the PubMed, Scopus, and Web of Science databases were performed for 5 methods of posterior spinal fixation, including (1) cortical bone trajectory (CBT) screws, (2) transfacet screws, (3) translaminar screws, (4) spinous process plates, and (5) fusion mass screws and hooks. Articles that had been published between January 1, 1990, and January 1, 2020, were considered. Non-English-language articles and studies involving fixation of the cervical or thoracic spine were excluded from our review.

RESULTS

After reviewing over 1,700 articles pertaining to CBT and non-pedicular fixation techniques, a total of 284 articles met our inclusion criteria. CBT and transfacet screws require less-extensive exposure and paraspinal muscle dissection compared with traditional pedicle screws and may therefore reduce blood loss, postoperative pain, and length of hospital stay. In addition, several methods of non-pedicular fixation such as translaminar and fusion mass screws have trajectories that are directed away from or posterior to the spinal canal, potentially decreasing the risk of neurologic injury. CBT, transfacet, and fusion mass screws can also be used as salvage techniques when traditional pedicle screw constructs fail.

CONCLUSIONS

CBT and non-pedicular fixation may be preferred in certain lumbar degenerative cases, particularly among patients with osteoporosis. Limitations of non-pedicular techniques include their reliance on intact posterior elements and the lack of 3-column fixation of the spine. As a result, transfacet and translaminar screws are infrequently used as the primary method of fixation. CBT, transfacet, and translaminar screws are effective in augmenting interbody fixation and have been shown to significantly improve fusion rates and clinical outcomes compared with stand-alone anterior lumbar interbody fusion.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Lifetime incremental cost-utility ratios for minimally invasive surgery for degenerative lumbar spondylolisthesis relative to failed medical management compared with total hip and knee arthroplasty for osteoarthritis

Background:

The objective of this study was to compare the cost-effectiveness of minimally invasive surgery (MIS) for patients with degenerative lumbar spondylolisthesis (DLS) relative to failed medical management with the cost-effectiveness of hip and knee arthroplasty for matched cohorts of patients with osteoarthritis.

Methods:

A cohort of patients with DLS undergoing MIS procedures with decompression alone or decompression and instrumented fusion between 2008 and 2014 was matched to cohorts of patients with hip osteoarthritis (OA) and knee OA undergoing total joint replacement. Incremental cost–utility ratios (ICURs) were calculated from the perspective of the Ontario Ministry of Health, using prospectively collected Short Form–6 Dimension utility data. Costs and quality-adjusted life years (QALYs) were discounted at 3% and sensitivity analyses were performed.

Results:

Sixty-six patients met the inclusion criteria for the DLS cohort (n = 35 for decompression alone), with a minimum follow-up time of 1 year (mean 1.7 yr). The mean age of patients in the DLS cohort was 64.76 years, and 45 patients (68.2%) were female. For each cohort, utility scores improved from baseline to follow-up and the magnitude of the gain did not differ by group. Lifetime ICURs comparing surgical with nonsurgical care were Can$7946/QALY, Can$7104/QALY and Can$5098/QALY for the DLS, knee OA and hip OA cohorts, respectively. Subgroup analysis yielded an increased ICUR for the patients with DLS who underwent decompression and fusion (Can$9870/QALY) compared with that for the patients with DLS who underwent decompression alone (Can$5045/QALY). The rank order of the ICURs by group did not change with deterministic or probabilistic sensitivity analyses.

Conclusion:

Lifetime ICURs for MIS procedures for DLS are similar to those for total joint replacement. Future research should adopt a societal perspective and potentially capture further economic benefits of MIS procedures.

Investigating Research Hotspots and Publication Trends of Spinal Stenosis: A Bibliometric Analysis During 2000-2018

Spinal stenosis is a common disease affecting the elderly that is present in a various forms. Its high incidence forces researchers to pay more attention and offer countermeasures. We used the Web of Science Core collection and PubMed database to obtain 5,606 scientific studies concerning spinal stenosis, and the number of publications maintained a roughly increasing trend from 108 in 2000 to 512 in 2018, only declining in 2011. Bibliometric analysis was conducted using the online analysis software CiteSpace and Bibliographic Item Co-Occurrence Matrix Builder (BICOMB). The United States maintains academic leadership in this field. The journal SPINE was the most authoritative, with 695 articles and an average of 12.73 citations. The exported major MeSH terms were further biclustered with gCLUTO according to co-word analysis to reveal research hotspots, including etiology, pathogenesis, clinical manifestation, conservative treatment, operative indication, internal implantation, and postoperative complications. After combination, the main topics focused on pathogenesis and surgical treatment. Narrowing causes flavum ligamentum hypertrophy, and posterior longitudinal ligament ossification is widely accepted. Additionally, minimally invasive surgery and internal implantation fixation are more valid in the clinic. Refining pathological classification and optimizing surgical methods and instrument properties will be important future research directions for spinal stenosis.

The Impact of Incorporating Evidence-Based Guidelines for Lumbar Fusion Surgery in Neurosurgical Resident Education

BACKGROUND

Instrumented fusion procedures are essential in the treatment of degenerative lumbar spine disease to alleviate pain and improve neurological function, but they are being performed with increasing incidence and variability. We implemented a training module for neurosurgery residents that is based on evidence-based criteria for lumbar fusion surgery and measured its effectiveness in residents' decision making regarding whether patients should or should not undergo instrumented fusion.

METHODS

The study design was a pretest versus posttest experiment conducted from September 2019 until July 2020 to measure improvement after formalized instruction on evidence-based guidelines. Neurosurgery residents of all training levels at our institution participated. A test was administered at the beginning of each academic year. The highest possible score was 18 points in each pretest and posttest.

RESULTS

There was a general trend of test score improvement across all levels of training with a greater degree of change for participants with lower compared with higher pretest scores, indicating a possible ceiling effect. Paired t test demonstrated an overall mean score increase of 2 points (P < 0.0001), equivalent to an 11.11% increase (P < 0.0001). Stratified by training group, mean absolute change in test score was 2 (P = 0.0217), 1.67 (P = 0.0108), and 2.25 (P = 0.0173) points for junior, midlevel, and senior training groups, respectively.

CONCLUSIONS

Incorporating a targeted evidence-based learning module for lumbar spine fusion surgery can improve neurosurgery residents' clinical decision making toward a more uniform practice supported by published data.

Best versus worst surgical outcomes after single-level posterior lumbar interbody fusion for degenerative spondylolisthesis

PURPOSE

Previous studies have shown conflicting results regarding the factors affecting the clinical outcome after fusion for degenerative spondylolisthesis. However, no study has compared the best and worst clinical outcome groups using patient-reported outcome measures. We aimed to compare the characteristics of patients with best and worst outcomes following single-level lumbar fusion for degenerative spondylolisthesis.

METHODS

200 patients underwent single-level interbody fusion with a minimum 2-years follow-up were included. We excluded patients with surgical complications already-known to be associated with poor postoperative outcomes, including pseudoarthrosis and postoperative infection. According to 2-year postoperative Oswestry disability index scores, patients were divided into two groups; Best and Worst. Demographic, clinical and radiographic variables were compared between the two groups.

RESULTS

Compared with patients in the Best group, those in the Worst group were older (59.5 and 67.0 years, respectively; p = 0.012; odds ratio [OR], 1.143; 95% confidence interval [CI], 1.030-1.269) and had a longer duration of pain from onset (2.6 and 7.2 years, respectively; p = 0.041; OR, 1.021; 95% CI, 1.001-1.041). The cutoff value of pain duration from onset was measured as ≥3.5 years on Receiver operating characteristic analysis. Patients in the Worst group had a lower preoperative angular motion compared to those in the Best group (12.7° and 8.3°, respectively; p = 0.016; OR, 0.816; 95% CI, 0.691-0.963).

CONCLUSIONS

Degenerative spondylolisthesis patients of good clinical outcome after single-level lumbar interbody fusion were relatively young, had a short symptom duration before surgery, and a high preoperative instability compared with the patient having poor postoperative clinical outcome. Therefore, these findings should be considered preoperatively when deciding the appropriate individual treatment plan.

Patient Outcomes After Single-level Coflex Interspinous Implants Versus Single-level Laminectomy

STUDY DESIGN

Retrospective cohort analysis.

OBJECTIVE

The aim of this study was to compare postoperative outcomes of Coflex interspinous device versus laminectomy.

SUMMARY OF BACKGROUND DATA

Coflex Interlaminar Stabilization device (CID) is indicated for one- or two-level lumbar stenosis with grade 1 stable spondylolisthesis in adult patients, as an alternative to laminectomy, or laminectomy and fusion. CID provides stability against progressive spondylolisthesis, retains motion, and prevents further disc space collapse.

METHODS

Patients ≥18 years' old with lumbar stenosis and grade 1 stable spondylolisthesis who underwent either primary single-level decompression and implantation of CID, or single-level laminectomy alone were included with a minimum 90-day follow-up at a single academic institution. Clinical characteristics, perioperative outcomes, and postoperative complications were reviewed until the latest follow-up. χ2 and independent samples t tests were used for analysis.

RESULTS

Eighty-three patients (2007-2019) were included: 37 cases of single-level laminectomy (48.6% female) were compared to 46 single-level CID (50% female). CID cohort was older (CID 69.0 ± 9.4 vs. laminectomy 64.2 ± 11.0, P = 0.042) and had higher American Society of Anesthesiologists (ASA) grade (CID 2.59 ± 0.73 vs. laminectomy 2.17 ± 0.48, P = 0.020). CID patients had higher estimated blood loss (EBL) (97.50 ± 77.76 vs. 52.84 ± 50.63 mL, P = 0.004), longer operative time (141.91 ± 47.88 vs. 106.81 ± 41.30 minutes, P = 0.001), and longer length of stay (2.0 ± 1.5 vs. 1.1 ± 1.0 days, P = 0.001). Total perioperative complications (21.7% vs. 5.4%, P = 0.035) and instrumentation-related complication was higher in CID (10.9% vs. 0% laminectomy group, P = 0.039). There were no other significant differences between the groups in demographics or outcomes.

CONCLUSION

Single-level CID devices had higher perioperative 90-day complications, longer operative time, length of stay, higher EBL compared to laminectomies alone. Similar overall revision and neurologic complication rates were noted compared to laminectomy at last follow-up.Level of Evidence: 3.