Clinical significance of redundant nerve roots in patients with lumbar stenosis undergoing minimally invasive tubular decompression.

Overview

abstract

OBJECTIVE: Symptomatic lumbar spinal stenosis (LSS) is a common indication for surgery in the elderly. Preoperative radiographic evaluation of patients with LSS often reveals redundant nerve roots (RNRs). The clinical significance of RNRs is uncertain. RNRs have not been studied in the setting of minimally invasive surgery. This study investigates the relationship between RNRs and clinical outcomes after minimally invasive tubular decompression. METHODS: Chart review was performed for patients with degenerative LSS who underwent minimally invasive decompression. Preoperative MRI parameters were assessed and patient reported outcomes (PROs) were analyzed. RESULTS: Fifty-four patients underwent surgery performed at an average of 1.8 +/- 0.8 spinal levels. Thirty-one patients (57%) had RNRs. Patients with RNRs were older (median 72 years vs 66 years, p = 0.050), had longer median symptom duration (32 months vs 15 months, p < 0.01), and had more levels operated on (2.1 vs 1.4; p <0.01). Median follow up after surgery was 2 months (range 1.3-12 months). Preoperative and post-operative PROs were similar based on RNR presence. Patients without RNRs had larger lumbar cross-sectional areas (CSA) (median 121 mm² vs. 95 mm², p = 0.014) and index level CSA (52 mm² vs. 34 mm², p = 0.007). CSA was not correlated with RNR morphology or location. CONCLUSION: Preoperative RNRs are associated with increased age, symptom duration, and lumbar stenosis severity. Patients improved after minimally invasive decompression regardless of RNR presence. RNR presence had no effect on short term clinical outcomes. Further study is required to assess their long-term significance.