RESUMEN
BACKGROUND: To report the long-term results of patients with lumbar spinal stenosis (LSS), for whom we applied the tubular and endoscopic approaches and previously published the short-term results. METHODS: A multicenter, prospective, randomized, double-blind study was carried out to evaluate 2 groups of patients with LSS who underwent microsurgery via a tubular retractor with a unilateral approach (T group) and bilateral spinal decompression using uniportal interlaminar endoscopic approaches (E group). Dural sac cross-sectional and spinal canal cross-sectional areas were measured with the patients' preoperative and postoperative magnetic resonance images. The visual analog scale, Oswestry Disability Index, and Japanese Orthopedic Association scores in the preoperative period and the first, second, and third years after surgery were evaluated. RESULTS: Twenty patients met the inclusion criteria for the research (T group; n = 10, E group; n = 10). The groups' visual analog scale (respectively; P = 0.315, P = 0.529, and P = 0.853), Oswestry Disability Index (respectively; P = 0.529, P = 0.739, and P = 0.912), and Japanese Orthopedic Association (respectively; P = 0.436, P =0.853, and P = 0.684) scores from the first, second, and third postoperative years were quite good compared with the preoperative period, but there was no statistically significant difference. A significant difference was found in the E group, with less blood loss (P < 0.001). CONCLUSIONS: The long-term results of the patients with LSS treated with tubular and endoscopic approaches were similar and very good. Bilateral decompression with minimally invasive spinal surgery methods can be completed with less tissue damage, complications, and blood loss with the unilateral approach.