MATERIAL and METHODS: Forty-one patients who underwent bilateral lumbar decompression with a unilateral approach between March 2020 and March 2022 at our clinic were followed up prospectively for 1 year from the date of their operation, and their sagittal balance parameters were measured by performing whole-body radiography. The measurements were analyzed and recorded with Surgimap® (Nemaris, Inc. product, USA). Patients were divided into 3 groups (<50 mm, ?50 mm- <100 mm, ?100 mm) according to their Sagittal Vertical Axis (SVA) values in preoperative measurements. The groups? clinical parameters and sagittal balance parameters were compared as preoperative and postoperative.

RESULTS: Significant improvements were detected in the sagittal balance parameters of patients who underwent bilateral decompression with a unilateral approach in the LSS. SVA values decreased significantly from 64.8 mm preoperatively to 48.6 mm. We observed a significant increase in the lumbar lordosis angle from 41.7? to 45.9?. Functional improvements were observed with clinical pain control and an increase in walking distance in these patients. Furthermore, improvements were also observed in compensatory mechanisms along with improvements observed in sagittal alignment. Pelvic tilt and knee flexion angles decreased.

CONCLUSION: Bilateral decompression surgery with a unilateral approach, which is a minimally invasive approach in patients with lumbar degenerative stenosis, is an effective method that causes improvements in sagittal balance parameters and compensation mechanisms in these patients and ensures clinical improvement in these patients. Keywords : Hemilaminotomy bilateral decompression, Lumbar spinal stenosis, Minimally invasive surgery, Unilateral laminotomy, Sagittal balance