[Clinical and radiological results of patients with central lumbar stenosis operated on with unilateral microscopic ''over the top'' technique: the void sign as a predictor of failure].

INTRODUCTION: lumbar spinal stenosis is a common condition in elderly patients, which can lead to neurogenic claudication or radiculopathy. One of the current surgical techniques used for decompression is the "over the top" approach, which consists of a unilateral microscopic decompression with partial resection of the lamina, ligamentum flavum, and part of the facet joint, without causing instability. The objective was to evaluate the clinical and radiological postoperative outcomes of patients with degenerative lumbar stenosis treated with the "over the top" technique.

MATERIAL AND METHODS: a retrospective study was conducted between January 2022 and December 2023. The Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) scales were used to assess clinical outcomes. The presence of the tomographic "vacuum sign" was evaluated, as well as imaging changes according to the Schizas classification. Postoperative complications and reoperations were also recorded.

RESULTS: a total of 56 patients were included. The preoperative lumbar VAS was 7.21 ± 1.24 [range 4-9], and at 12 months it was 3.11 ± 1.54 [range 2-8] (p < 0.00001). The preoperative ODI was 32 ± 8.02 [range 25-39]; at 12 months, it significantly improved to 14.92 ± 5.03 [range 7-26] (p < 0.00001). A statistically significant association was found between patients with preoperative pneumodisc and those who underwent reoperation (p = 0.025). No patients showed signs of postoperative instability on radiographic assessment.

CONCLUSION: the minimally invasive "over the top" decompression technique provides good clinical outcomes in the surgical treatment of lumbar spinal stenosis.