Clinical Significance of Redundant Nerve Roots in Patients with Lumbar Stenosis Undergoing Minimally Invasive Tubular Decompression

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 magnetic resonance imaging parameters were assessed, and patient-reported outcomes 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). The median follow-up after surgery was 2 months (range = 1.3-12 months). Preoperative and postoperative patient-reported outcomes were similar based on RNR presence. Patients without RNRs had larger lumbar cross-sectional areas (CSAs) (median = 121 mm² vs. 95 mm², P = 0.014) and the index-level CSA (52 mm² vs. 34 mm², P = 0.007). The CSA was not correlated with RNR morphology or location.

CONCLUSIONS

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.

Comparison of lumbar endoscopic unilateral laminotomy bilateral decompression and minimally invasive surgery transforaminal lumbar interbody fusion for one-level lumbar spinal stenosis

BACKGROUND

The aim of the present study is to compare the clinical outcomes and postoperative complications of lumbar endoscopic unilateral laminotomy bilateral decompression (LE-ULBD) and minimally invasive surgery transforaminal lumbar interbody fusion (MIS-TLIF) to treat one-level lumbar spinal stenosis (LSS) without degenerative spondylolisthesis or deformity.

METHODS

A retrospective analysis of 112 consecutive patients of one-level LSS undergoing either LE-ULBD or MIS-TLIF was performed. Patient demographics, operation time, estimated blood loss, time to ambulation, length of hospitalization, intraoperative and postoperative complications were recorded. The visual analog scale (VAS) score for leg and back pain, the Oswestry Disability Index (ODI) score, and the Macnab criteria were used to evaluate the clinical outcomes. The healthcare cost was also recorded.

RESULTS

The operation time, estimated blood loss, time to ambulation and length of hospitalization of LE-ULBD group were shorter than MIS-TLIF group. The postoperative mean VAS and ODI scores decreased significantly in both groups. According to the modified Macnab criteria, the outcomes rated as excellent/good rate were 90.6 and 93.8% in the two groups. The mean VAS scores, ODI scores and outcomes of the modified Macnab criteria of both groups were of no significant difference. The healthcare cost of LE-ULBD group was lower than MIS-TLIF group. Two cases of intraoperative epineurium injury were observed in the LE-ULBD group. One case of cauda equina injury was observed in the LE-ULBD group. No nerve injury, dural injury or cauda equina syndrome was observed in MIS-TLIF group. However, one case with transient urinary retention, one case with pleural effusion, one case with incision infection and one case with implant dislodgement were observed in MIS-TLIF group.

CONCLUSIONS

Both LE-ULBD and MIS-TLIF are safe and effective to treat one-level LSS without degenerative spondylolisthesis or deformity. LE-ULBD is a more minimally invasive option and of less economic burden compared with MIS-TLIF. Decompression plus instrumented fusion may be not necessary for one-level LSS without degenerative spondylolisthesis or deformity.