L5-S3 Compared to L5-S2 Full-Endoscopic Rhizotomy and Ablation Under a Navigation System for Sacroiliac Joint Pain: A Comparative Study.

Background: Chronic low back pain (CLBP) with sacroiliac joint (SIJ) involvement is a prevalent issue in health care. Surgical intervention, employing an endoscopic technique with a navigation system, targets and ablates nociceptive nerve fibers associated with SIJ pain, although the clinical effect of omitting rhizotomy of the lateral sacral branch of S3 remains uncertain.

Objectives: This study aimed to compare the clinical outcomes of 2 full-endoscopic rhizotomy and ablation (FERA) techniques for SIJ pain and to determine the effect of omitting rhizotomy of the lateral sacral branch of S3 on patient outcomes.

Study design: This study adopted a retrospective cohort study design.

Setting: This study was conducted at a single medical institution by a neurosurgeon.

Methods: From January 2018 through March 2021, the records of 73 patients undergoing L5-S3 or L5-S2 FERA for SIJ pain associated with CLBP were retrospectively reviewed. The patients were evaluated using the Visual Analog Scale (VAS) for pain, Oswestry Disability Index (ODI) for functional disability, and MacNab criteria for satisfaction. The procedures were guided by 3-D robotic C-arm navigation. The L5-S3 FERA group underwent rhizotomy and ablation of the L5-S3 lateral branches, whereas the L5-S2 FERA group did not undergo rhizotomy of the S3 lateral sacral branch.

Results: Both groups showed significant  improvements at one year in VAS and ODI scores with similar trends. The L5-S2 FERA group had a shorter operative time, particularly bilaterally, without complications. Although the L5-S3 FERA group initially presented a slightly higher recurrence rate at 6 months, their recurrence rate was equal with that of the L5-S2 FERA group at one year. Furthermore, the MacNab criteria showed comparable satisfaction rates in both groups.

Limitation: This was a small retrospective study.

Conclusion: L5-S2 FERA demonstrated clinical outcomes similar to those of L5-S3 FERA for pain relief, functional improvement, and satisfaction. Omitting S3 lateral branch rhizotomy did not adversely affect the outcomes. Surgeons may consider omitting S3 lateral branch rhizotomy for SIJ pain treatment, thereby reducing operative time while maintaining patient benefits.