Microscopic Discectomy of Axillary Lumbar Disc Herniation: Surgical Technique and Clinical Outcomes

Background: Lumbar disc herniation (LDH) can be categorized based on its relation to the nerve root into shoulder type and axillary type. This study assesses the safety and clinical outcome of microscopic discectomy (MD) for axillary LDH. Methods: We retrospectively reviewed 27 patients with axillary LDH. The Visual Analogue Scale (VAS) was used to assess low back pain and sciatica, and the Medical Research Council (MRC) grading scale was used to evaluate lower limb motor power. Oswestry Disability Index (ODI) and Modified Macnab Criteria (MMC) were used to assess patient functional outcomes. Procedure time, intraoperative findings, and/or complications were documented. Results: A total of 27 patients (15 females (55.6%) and 12 males (44.4%)), with a mean age of 39.6 ± 9.3 years, underwent axillary LDH by MD. MRI revealed L4-L5 in 10 patients (37%) and L5-S1 in 17 patients (63%), with radiological kissing sign in all patients (100%). Mean operative time was 125.92 ± 16 minutes. Intraoperatively, adhesions, a sequestrated free fragment, and an increased axillary space with a divergent nerve root were reported in 18 patients (66.7%), all patients (100%), and 21 patients (77.8%), respectively. Postoperatively, sciatica improved in all patients (100%) before discharge. The lower extremity weakness improved on discharge in 4 out of 7 (57.1%) patients, after one week in two (28.6%) patients, and after four weeks in one (14.3%) patient, as they became intact in motor power according to the MRC grading scale. All patients had excellent function and regained normal daily activities, as indicated by ODI and MMC scores. Conclusion: Axillary lumbar disc herniation can be successfully treated with microscopic discectomy, with excellent clinical outcome. Preoperative diagnosis is crucial, and the adoption of a tailored, meticulous surgical technique will help avoid surgical drawbacks.