Mobility-Preserving Surgery for Lumbar Spinal Stenosis: WFNS Spine Committee Recommendations

Dynamic Rod Constructs as the Preventive Strategy against Adjacent Segment Disease in Degenerative Lumbar Spinal Disorders: A Retrospective Comparative Cohort Study

Objectives

Adjacent segment degeneration (ASDe) and adjacent segment disease (ASDi) are potential long-term complications after lumbar fusion with rigid instrumentation. Dynamic fixation techniques (Topping-off) adjacent to the fused segments have been developed to curtail the risk of ASDe and ASDi. The current study sought to investigate whether the addition of dynamic rod constructs (DRC) in patients with preoperative degeneration in the adjacent disc was effective in reducing the risk of ASDi.

Methods

A retrospective analysis was performed on clinical data of 207 patients with degenerative lumbar disorders (DLD) from January 2012 to January 2019, who underwent posterior transpedicular lumbar fusion (without Topping-off, NoT/O), and posterior dynamic instrumentation with DRC. Clinical and radiological outcomes were evaluated using Oswestry Disability Index (ODI), Visual Analogue Scale (VAS), and lumbar radiographs one, three, and 12 months postoperatively and annually. ASDe was defined as disc height collapse > 20% and disc wedging > 5. Patients with confirmed ASDe and aggravation of ODI > 20 or VAS score > 5 at final follow-up were diagnosed as ASDi. The Kaplan-Meier hazard method was used to estimate the cumulative probability of ASDi within 63 months of surgery.

Results

Over three years of follow-up, 65 patients in the NoT/O (59.6%) and 52 cases (53.1%) in the DRC groups met the diagnostic criteria for ASDe. Furthermore, 27 (24.8%) patients in the NoT/O group showed ASDi during the follow-up, compared to 14 (14.3%) cases in the DRC group (P=0.059). Revision surgery was performed on 19 individuals in the NoT/O and 8 cases in the DRC groups (P=0.048). The Cox regression model identified a significantly decreased risk of ASDi if DRC was used (Hazard ratio: 0.29; 95% CI: 0.13-0.6).

Conclusion

Dynamic fixation adjacent to the fused segment is an effective strategy for preventing ASDi in carefully selected individuals with preoperative degenerative changes at the adjacent level.

Dynamic Fixation Techniques for the Prevention of Adjacent Segment Disease: A Retrospective Controlled Study

Study Design

Retrospective, controlled study.

Purpose

Dynamic fixation (topping-off technique) adjacent to a transforaminal lumbar interbody fusion (TLIF) level was developed to reduce the risk of adjacent segment disease (ASDi). This study was designed to compare the clinical and radiological outcomes between patients who underwent circumferential lumbar fusion (CLF) without the topping-off technique, CLF with dynamic rod constructs (DRC), and CLF with interspinous device (ISD).

Overview of Literature

Lumbar fusion can result in the re-distribution of stress, increased mobility, and increased intradiscal pressure at adjacent levels, ultimately leading to adjacent segment degeneration (ASDe) and ASDi. Dynamic fixation techniques (topping-off techniques) adjacent to vertebral fusion have been developed to reduce the risk of ASDe and ASDi because they provide a transitional zone between a caudal rigid fused segment and cephalad-mobile unfused levels.

Methods

A single-center, retrospective, controlled study was designed, including all patients who underwent CLF due to degenerative lumbar spinal disease in Hospital Clinic of Barcelona between 2012 and 2018. Three groups of patients were evaluated as per the type of topping-off technique used: CLF alone group, DRC group, and ISD group. Clinical and radiological outcomes were evaluated.

Results

A total of 117 patients were enrolled in the study. Sixty patients (51.3%) underwent CLF without dynamic stabilization, 24 (20.5%) were treated with DRC as topping-off technique, and 33 (28.5%) were treated with an ISD. A total of 12 patients (20.0%) in the CLF alone group showed ASDi at the final follow-up, compared to 1 (4.2%) in the DRC group (p=0.097) and 2 (6.1%) in the ISD group (p=0.127). The Cox regression model identified a significantly decreased risk of ASDi when a topping-off technique (DRC or ISD) was used (hazard ratio, 0.154; 95% confidence interval, 0.31–0.77).

Conclusions

Dynamic fixation adjacent to CLF was a safe and efficient procedure associated with improved clinical outcomes in patients with lumbar spine degenerative disease.

Degenerative Lumbar Spine Stenosis Consensus Conference: the Italian job. Recommendations of the Spinal Section of the Italian Society of Neurosurgery

In the modern era evidence-based medicine, guidelines and recommendations represent a key-point of daily activity. The Spinal Section of the Italian Society of Neurosurgery introduced some recommendations regarding Degenerative Lumbar Spine Stenosis based on those of the Spine Committee of World Federation of Neurosurgical Societies, revising them on the basis of Italian common practice. In June 2019, a Committee of 21 spine surgeons met in Rome to validate the recommendations of the WFNS. Furthermore, they decided to review the ones that did not reach a consensus to create Italian Recommendations on Degenerative Lumbar Spine Stenosis. A literature review of the last ten years was performed and the statements were voted using the Delphi method. Forty-one statements were discussed, and 7 statements were voted again to reach a consensus with respect to those of the WFNS. A total of 40 statements reached a consensus, of which 36 reached a positive consensus and 4 a negative consensus, while no consensus was reached in 1 case. Conservative multimodal therapy, tailored on the patient, is a reasonable and effective first option choice for the treatment of LSS patients with tolerable moderate symptoms. Surgical treatment is reserved for symptomatic patients non-responding to conservative treatment or with neurological deficits. The best surgical technique to use depends on personal experience; modern MISS techniques are equivalent to open decompressive surgery with some advantages and higher cost-effectiveness. Fusion surgery and mobility preserving surgery only have a marginal role in the treatment of DLSS without instability.