Pathomechanisms and Predisposing Factors for Degenerative Lumbar Spondylolisthesis: A Narrative Review

The disaggregation of the oswestry disability index in patients undergoing lumbar surgery for degenerative lumbar spondylolisthesis

BACKGROUND CONTEXT

The Oswestry Disability Index (ODI), is a widely used patient-reported outcome measure (PROM) for assessing functional status in individuals with lumbar spine pathology. The ODI is used by surgeons to determine the initial status and monitor progress after surgery. Compiled ODI data enables comparisons between different surgical techniques. Degenerative lumbar spondylolisthesis (DLS) often causes symptoms such as back pain and neurogenic claudication affecting quality of life and activities of daily living captured by the ODI. Despite extensive studies on ODI changes after spinal surgery, little is known about the characteristics and changes in the different ODI subsections.

PURPOSE

To analyze the baseline characteristics and changes in total ODI and ODI subsections 2 years after elective lumbar surgery.

STUDY DESIGN

Retrospective analysis on patients prospectively enrolled who underwent spinal surgery for degenerative lumbar spondylolisthesis from 2016 to 2018. The ODI was assessed preoperatively and 2 years postoperatively.

PATIENT SAMPLE

A total of 265 patients were included in the study, 60% were female. The mean age of the patients was 67±8 years, and the mean BMI was 30±6 kg/m2.

OUTCOME MEASURES

The analysis considered the differences in ODI scores before and after surgery, as well as the changes in all ODI subsections 2 years after elective lumbar surgery for DLS.

METHODS

The analysis evaluated differences in ODI scores and variations in different subsections. Patients without an ODI follow-up at 2 years were excluded from the study. The study utilized the Wilcoxon Signed Rank Test for all prepost paired samples. The Wilcoxon rank sum test was used for sex and procedure comparisons for overall ODI and ODI subsection analysis. Univariate linear regression was applied for overall and subsection specific ODI outcomes with age and BMI as independent variables, respectively. The statistical significance level was set at p<.05.

RESULTS

Improvement in ODI was observed in 242 patients (91%). The highest baseline disability values were found for the questions regarding pain intensity (3.4±1.3), lifting (3.2±1.9), and standing (3.4±1.3). The lowest preoperative functional limitations were observed in sleeping (1.6±1.3), personal care (1.6±1.4), traveling (1.6±1.2) and sitting (1.5±1.4). At the 2-year follow-up, there was significant improvement in all questions and the overall ODI (all p<.001). The ODI subsections that showed the greatest absolute improvements were changing degree of pain (-2.6), with 89% of patients experiencing improvement, standing (-2.4) with 87% of patients experiencing improvement, and pain intensity (-2.1) with 81% of patients experiencing improvement. The subsections with the least improvement were personal care (-0.6), sitting (-0.7), and sleeping (-0.9). The study found that female patients had a significantly higher preoperative disability in various subsections but showed greater improvement in total ODI compared to male patients (p=.001). Additionally, improvement in sitting (p<.001), traveling (p<.001), social life (p<.001) and sleeping (p=.018) were significantly higher in female patients. Older patients showed significantly less improvement in sitting (p=.005) and sleeping (p=.002). A higher BMI was significantly associated with less improvement in changing degree of pain (p=.025) and higher baseline disability in various subsections. Patients who underwent decompression and fusion had significantly higher baseline disability in several subsections compared to those who underwent decompression alone. There was no significant difference between decompression alone and decompression with fusion in terms of overall improvement in the ODI and improvement in the subsections.

CONCLUSION

These results offer a more comprehensive understanding of ODI and its changes across different subsections. This insight is invaluable for improving preoperative education and effectively managing patient expectations regarding potential postsurgery disability in specific areas.

The relationship between paraspinal muscle atrophy and degenerative lumbar spondylolisthesis at the L4/5 level

BACKGROUND/CONTEXT

Degenerative lumbar spondylolisthesis (DLS) is a prevalent spinal condition that can result in significant disability. DLS is thought to result from a combination of disc and facet joint degeneration, as well as various biological, biomechanical, and behavioral factors. One hypothesis is the progressive degeneration of segmental stabilizers, notably the paraspinal muscles, contributes to a vicious cycle of increasing slippage.

PURPOSE

To examine the correlation between paraspinal muscle status on MRI and severity of slippage in patients with symptomatic DLS.

STUDY DESIGN/SETTING

Retrospective cross-sectional study at an academic tertiary care center.

PATIENT SAMPLE

Patients who underwent surgery for DLS at the L4/5 level between 2016-2018 were included. Those with multilevel DLS or insufficient imaging were excluded.

OUTCOME MEASURES

The percentage of relative slippage (RS) at the L4/5 level evaluated on standing lateral radiographs. Muscle morphology measurements including functional cross-sectional area (fCSA), body height normalized functional cross-sectional area (HI) of Psoas, erector spinae (ES) and multifidus muscle (MF) and fatty infiltration (FI) of ES and MF were measured on axial MR. Disc degeneration and facet joint arthritis were classified according to Pfirrmann and Weishaupt, respectively.

METHODS

Descriptive and comparative statistics, univariable and multivariable linear regression models were utilized to examine the associations between RS and muscle parameters, adjusting for confounders sex, age, BMI, segmental degeneration, and back pain severity and symptom duration.

RESULTS

The study analyzed 138 out of 183 patients screened for eligibility. The median age of all patients was 69.5 years (IQR 62 to 73), average BMI was 29.1 (SD±5.1) and average preoperative ODI was 46.4 (SD±16.3). Patients with Meyerding-Grade 2 (M2, N=25) exhibited higher Pfirrmann scores, lower MFfCSA and MFHI, and lower BMI, but significantly more fatty infiltration in the MF and ES muscles compared to those with Meyerding Grade 1 (M1). Univariable linear regression showed that each cm2 decrease in MFfCSA was associated with a 0.9%-point increase in RS (95% CI -1.4 to - 0.4, p<.001), and each cm2/m2 decrease in MFHI was associated with an increase in slippage by 2.2%-points (95% CI -3.7 to -0.7, p=.004). Each 1%-point rise in ESFI and MFFI corresponded to 0.17%- (95% CI 0.05-0.3, p=.01) and 0.20%-point (95% CI 0.1-0.3 p<.001) increases in relative slippage, respectively. Notably, after adjusting for confounders, each cm2 increase in PsoasfCSA and cm2/m2 in PsoasHI was associated with an increase in relative slippage by 0.3% (95% CI 0.1-0.6, p=.004) and 1.1%-points (95% CI 0.4-1.7, p=.001). While MFfCSA tended to be negatively associated with slippage, this did not reach statistical significance (p=.105). However, each 1%-point increase in MFFI and ESFI corresponded to increases of 0.15% points (95% CI 0.05-0.24, p=.002) and 0.14% points (95% CI 0.01-0.27, p=.03) in relative slippage, respectively.

CONCLUSION

This study found a significant association between paraspinal muscle status and severity of slippage in DLS. Whereas higher degeneration of the ES and MF correlate with a higher degree of slippage, the opposite was found for the psoas. These findings suggest that progressive muscular imbalance between posterior and anterior paraspinal muscles could contribute to the progression of slippage in DLS.

Surgical treatment of degenerative lumbar spondylolisthesis: Effect of TLIF and slip reduction on sagittal alignment

INTRODUCTION

The surgical treatment of lumbar degenerative spondylolisthesis (LDS) remains controversial. The aim of this study was to determine the effect of adding transforaminal lumbar interbody fusion (TLIF) to posterolateral fusion (PLF) on the local lordosis, sagittal alignment and potential complications. The second aim was to evaluate the effect of slip reduction on the same parameters.

HYPOTHESIS

The initial hypothesis was that TLIF provides better correction of the local lordosis and that reducing the slip improves the global sagittal balance.

METHODS

In this retrospective, single-center study, patients who had been operated on for LSD at one or two levels by laminectomy and PLF, with or without a TLIF cage, were included. Data collected consisted of age, sex, number of levels fused and whether or not a TLIF cage was used. Fusion was defined as the absence of indirect nonunion signs on radiographs at 2 years postoperative. The occurrence and time frame of any complications and the need for reoperation were documented. Lateral radiographs of the entire spine were analyzed preoperatively, in the early postoperative period (3 to 6 months) and at a minimum follow-up of 2 years. The following parameters were measured: pelvic parameters, C7 sagittal tilt (C7ST), spinosacral angle (SSA), maximum lumbar lordosis (LL), lordosis at slipped level (LS), slip percentage. The analysis compared patients treated by PLF and TLIF and determined the impact of slip reduction.

RESULTS

One hundred and three patients were included in the study (71% women). The mean follow-up was 38 months. The mean age was 69 years. Seventy-seven patients (75%) underwent PLF. Comparing the preoperative and early postoperative data identified 5.4% better spondylolisthesis reduction in the TLIF group than the PLF group (-8.9±9.5% vs -3.5±7.6%; p=0.04) that was not maintained at the final follow-up. The fusion rate was comparable between groups: 94% in APL and 89% in TLIF (p=0.7). The overall complication rate was 46% in the TLIF group versus 33% in the PLF group (p=0.35). A comparison based on whether or not the slip was reduced found significant improvement in the reduction group of the SSA by more than 6° (6.8°±6° vs 0.5°±7.4°; p=0.04). The fusion rate was 91% in the reduced group and 95% in the non-reduced group (p=0.81); the complication rate was 44% versus 28% in the non-reduced group (p=0.10).

CONCLUSION

This study shows that slip reduction helps to improve the sagittal alignment by increasing the SSA when treating LDS. Posterolateral fusion and TLIF produce comparable radiographic outcomes at 2 years postoperative in the segmental lordosis, slip reduction, global sagittal alignment and fusion rate.

LEVEL OF EVIDENCE

IV.

Abnormal L5-S1 Facet Joint Orientation as a Harbinger of Degenerative Spondylolisthesis: A Case Report

Degenerative spondylolisthesis is a common cause of low back pain and resultant disability in the adult population. The causes of degenerative spondylolisthesis are not entirely understood, though a combination of anatomic and lifestyle factors likely contributes to the development of this pathology. Here, we report a case of a 38-year-old female presenting with low back pain and right lower extremity radiculopathy, found to have degenerative L5-S1 spondylolisthesis, which we postulate developed in part due to the sagittal orientation of her L5-S1 facet joints bilaterally.

Reoperations after primary and revision lumbar discectomy: study of a national-level cohort with eight years follow-up

BACKGROUND CONTEXT

Published rates for disc reherniation following primary discectomy are around 6%, but the ultimate reoperation outcomes in patients after receiving revision discectomy are not well understood. Additionally, any disparity in the outcomes of subsequent revision discectomy (SRD) versus subsequent lumbar fusion (SLF) following primary/revision discectomy remains poorly studied.

PURPOSE

To determine the 8-year SRD/SLF rates and time until SRD/SLF after primary/revision discectomy respectively.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Patients undergoing primary or revision discectomy, with records in the PearlDiver Patient Records Database from the years 2010 to 2019.

OUTCOME MEASURES

Subsequent surgery type and time to subsequent surgery.

METHODS

Patients were grouped into primary or revision discectomy cohorts based off of the nature of "index" procedure (primary or revision discectomy) using ICD9/10 and CPT procedure codes from 2010 to 19 insurance data sets in the PearlDiver Patient Records Database. Preoperative demographic data was collected. Outcome measures such as subsequent surgery type (fusion or discectomy) and time to subsequent surgery were collected prospectively in PearlDiver Mariner database. Statistical analysis was performed using BellWeather statistical software. A Kaplan-Meier survival analysis of time to SLF/SRD was performed on each cohort, and log-rank test was used to compare the rates of SLF/SRD between cohorts.

RESULTS

A total of 20,147 patients were identified (17,849 primary discectomy, 2,298 revision discectomy). The 8-year rates of SRD (6.1% in revision cohort, 4.8% in primary cohort, p<.01) and SLF (10.4% in revision cohort, 6.2% in primary cohort, p<.01) were higher after revision versus primary discectomy. Time to SLF was shorter after revision versus primary discectomy (709 vs. 886 days, p<.01). After both primary and revision discectomy, the 8-year rate of SLF (10.4% in revision cohort, 6.2% in primary cohort, p<.01) is greater than SRD (6.1% in revision cohort, 4.8% in primary cohort, p<.01).

CONCLUSIONS

Compared to primary discectomy, revision discectomy has higher rates of SLF (10.4% vs. 6.2%), and faster time to SLF (2.4 vs. 1.9 years) at 8-year follow up.