Risk Factors for Reoperation at Same Level after Decompression Surgery for Lumbar Spinal Stenosis in Patients with Diffuse Idiopathic Skeletal Hyperostosis Extended to the Lumbar Segments

Risk of further surgery after decompression in patients with diffuse idiopathic skeletal hyperostosis extending to the lumbar segments: focus on the number of residual lumbar/lumbosacral and sacroiliac mobile segments

PURPOSE

Patients with diffuse idiopathic skeletal hyperostosis (DISH) that extends to the lumbar segments (L-DISH) have a high risk of further surgery after lumbar decompression. However, few studies have focused on the ankylosis status of the residual caudal segments, including the sacroiliac joint (SIJ). We hypothesized that patients with more ankylosed segments beside the operated level, including the SIJ, would be at a higher risk of further surgery.

METHODS

A total of 79 patients with L-DISH who underwent decompression surgery for lumbar stenosis at a single academic institution between 2007 and 2021 were enrolled. The baseline demographics and radiological findings by CT imaging focusing on the ankylosing condition of the residual lumbar segments and SIJ were collected. Cox proportional hazard analysis was conducted to investigate the risk factors for further surgery after lumbar decompression.

RESULTS

The rate of further surgery was 37.9% during an average of 48.8 months of follow-up. Cox proportional hazard analysis demonstrated that the presence of fewer than three segments of non-operated mobile caudal segments was an independent predictor for further surgery (including both the same and adjacent levels) after lumbar decompression (adjusted hazard ratio 2.53, 95%CI [1.12-5.70]).

CONCLUSIONS

L-DISH patients with fewer than three mobile caudal segments besides index decompression levels are at a high risk of further surgery. Ankylosis status of the residual lumbar segments and SIJ should be thoroughly evaluated using CT during preoperative planning.

Less-invasive decompression procedures can reduce risk of reoperation for lumbar spinal stenosis with diffuse idiopathic skeletal hyperostosis extended to the lumbar segment: analysis of two retrospective cohorts

PURPOSE

Clinical outcomes after decompression procedures are reportedly worse for lumbar spinal stenosis (LSS) with diffuse idiopathic skeletal hyperostosis (DISH), especially DISH extended to the lumbar segment (L-DISH). However, no studies have compared the effect of less-invasive surgery versus conventional decompression techniques for LSS with DISH. The purpose of this study was to compare the long-term risk of reoperation after decompression surgery focusing on LSS with L-DISH.

METHODS

This study compared open procedure cohort (open conventional fenestration) and less-invasive procedure cohort (bilateral decompression via a unilateral approach) with ≥ 5 years of follow-up. After stratified analysis by L-DISH, patients with L-DISH were propensity score-matched by age and sex.

RESULTS

There were 57 patients with L-DISH among 489 patients in the open procedure cohort and 41 patients with L-DISH among 297 patients in the less-invasive procedure cohort. The reoperation rates in L-DISH were higher in the open than less-invasive procedure cohort for overall reoperations (25% and 7%, p = 0.026) and reoperations at index levels (18% and 5%, p = 0.059). Propensity score-matched analysis in L-DISH demonstrated that open procedures were significantly associated with increased overall reoperations (hazard ratio [HR], 6.18; 95% confidence interval [CI], 1.37-27.93) and reoperations at index levels (HR, 4.80; 95% CI, 1.04-22.23); there was no difference in reoperation at other lumbar levels.

CONCLUSIONS

Less-invasive procedures had a lower risk of reoperation, especially at index levels for LSS with L-DISH. Preserving midline-lumbar posterior elements could be desirable as a decompression procedure for LSS with L-DISH.

Prognostic Factors and Optimal Surgical Management for Lumbar Spinal Canal Stenosis in Patients with Diffuse Idiopathic Skeletal Hyperostosis

Lumbar spinal canal stenosis (LSS) and diffuse idiopathic skeletal hyperostosis (DISH) tend to develop in the elderly, resulting in an increased need for lumbar surgery. However, DISH may be a risk factor for poor clinical outcomes following lumbar decompression surgery, especially in patients with DISH extending to the lumbar segment (L-DISH). This study aimed to identify the prognostic factors of LSS with L-DISH and propose an optimal surgical management approach to improve clinical outcomes. Of 934 patients who underwent lumbar decompression surgery, 145 patients (15.5%) had L-DISH. In multivariate linear regression analysis of the JOA score improvement rate, the presence of vacuum phenomenon at affected segments (estimate: −15.14) and distance between the caudal end of L-DISH and decompressed/fused segments (estimate: 7.05) were independent prognostic factors. In logistic regression analysis of the surgical procedure with JOA improvement rate > 25% in L-DISH patients with both negative prognostic factors, the odds ratios of split laminotomy and short-segment fusion were 0.64 and 0.21, respectively, with conventional laminotomy as the reference. Therefore, to achieve better clinical outcomes in cases with decompression at the caudal end of L-DISH, decompression surgery without fusion sparing the osteoligamentous structures at midline should be considered as the standard surgery.