Abstract
BACKGROUND: Far lateral disc herniations (FLDHs) are foraminal and extra-foraminal disc prolapses that comprise only 7-12% of all lumbar disc herniations. They compress the exiting nerve root and dorsal root ganglion (DRG) accounting for an increased severity of pain and neurological deficit compared to standard posterolateral and medial foraminal disc prolapses. There is a paucity of data on the mid-to-long-term outcomes and reoperation rates following a far lateral microdiscectomy (FLMD) operation. We report mid-term follow-up of patients undergoing FLMD using a Wiltse muscle-splitting approach that optimises approach angle to the lateral and foraminal disc with minimal facet joint removal and preservation of the pars interarticularis. The aim of this study is to report the mid-to-long-term outcomes and reoperation rates in a cohort of patients undergoing FLMD via a Wiltse approach. METHODS: Single centre, single surgeon, retrospective analysis of consecutive patients underwent lumbar FLMD. A cohort of 50 patients from one senior spine surgeon were included. Patient-reported outcome measures (PROMs), visual analogue scale (VAS back and leg), Oswestry Disability Index (ODI) and short-form-12 (SF-12), patient satisfaction using Odom's criteria, recurrence and reoperation rates were evaluated preoperatively, at 6 weeks postoperatively, and at last follow-up. All consecutive patients underwent a lumbar FLMD via a paramedian Wiltse approach from January 2010 to December 2021. Minimum follow-up was 3 years. RESULTS: The mean patient age was 60.6±14.1 years, body mass index (BMI) 27.9±2.6 kg/m(2), and 25 (50.0%) were male. The mean operation time was 77±17 minutes and the mean follow-up was 5.2 years (range, 3-14 years). All PROMs improved significantly from the pre-operative consultation to the last post-operative follow-up (P<0.001). Forty-two (84%) reported excellent or good outcomes. There were no dural tears, nerve root injuries, residual neuropathic pain or infections, and no known iatrogenic pars defects or facet fractures. Eight (16%) patients needed reoperation. Two patients had a revision FLMD within 2 weeks postoperatively. Six patients had interbody fusions at a mean 1.9 years (range, 0.17-3 years) post-index FLMD. CONCLUSIONS: FLMD via a Wiltse approach is safe and effective for decompressing the exiting nerve root and the DRG, providing excellent visualisation of the pathology and the exiting root, while requiring minimal bone removal. This mid-term follow-up demonstrated over 80% of patients reported early mobilization with excellent or good outcomes. Subsequent interbody fusions were performed for either symptomatic disc degeneration, foraminal stenosis, or both, rather than for instability.