Abstract
OBJECTIVE: Degenerative lumbar spondylolisthesis often leads to bilateral spinal canal and intervertebral foramen stenosis, yet symptoms frequently present unilaterally. The need for decompression on the asymptomatic or mildly symptomatic side remains a topic of debate. METHODS: There were 28 patients with single-level degenerative lumbar spondylolisthesis (Meyerding grades I/II) with bilateral symptoms were selected for this study. We measured preoperative and postoperative foramen height (FH), foraminal area (FA), disc height (DH), cross-sectional area of spinal canal(CASC), and degree of upper vertebral slip (DUVS). Clinical outcomes were assessed using the visual analog scale (VAS), Oswestry Disability Index (ODI), and the Macnab standard was used to evaluate the efficacy at the last postoperative follow-up. RESULTS: All parameters on the surgical side and the contralateral side presented a significant increase compared to preoperative values (P < 0.001). The postoperative values for FH on operative and contralateral sides were 18.13 ± 1.19 mm and 18.49 ± 1.09 mm, for FA were 120.04 ± 23.57 mm(2) and 123.07 ± 21.51 mm(2), for DH were 8.53 ± 0.77 mm, and the cross-sectional area of spinal canal were 117.29 ± 16.83(2). The VAS scores and ODI scores for lumbar pain and bilateral leg pain improved significantly. CONCLUSION: Satisfactory ipsilateral direct and contralateral indirect decompression can be achieved by unilateral-approach RA-ULIF.Routine decompression on the contralateral side may not be necessary for patients with bilateral symptoms and bilateral intervertebral foramen stenosis in single-level lumbar spondylolisthesis, barring cases of severe spinal stenosis. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12891-025-09333-0.