Minimally Invasive Interlaminar Decompression with a 10-mm Endoscope and Microscope in Cases of Adult Degenerative Scoliosis

BACKGROUND: Adult degenerative (de novo) scoliosis (ADS) usually occurs due to degenerative changes and is accompanied by progressive low-back pain and/or symptomatic lumbar stenosis. Interlaminar decompression is considered an effective treatment of lumbar stenosis, but some surgical contraindications to traditional open surgery limit its application in elderly patients with many disorders. A 10-mm endoscope has been used in the treatment of stenosis in individuals with ADS and its safety and efficacy should be assessed. OBJECTIVE: The objective was to conduct a retrospective analysis to compare interlaminar decompression with a 10-mm endoscope versus a microscope. STUDY DESIGN: Retrospective study. SETTING: This study took place at the First Affiliated Hospital of Harbin Medical University. METHODS: The data of 34 ADS patients treated in our hospital from January 2018 to December 2019, who underwent decompression with a 10-mm endoscope (ES group, 19 patients) or microscope (MS group, 15 patients) were retrospectively reviewed. The two methods were compared using the visual analog scale (VAS), Japanese orthopedic association (JOA) scale, and Oswestry disability index (ODI). Lumbar stability was also evaluated by the progression of scoliosis. RESULTS: There were no significant differences between the 2 groups in demographic or clinical characteristics. The mean preoperative Cobb angle of all patients was 23.34° ± 6.44°, which indicated degenerative scoliosis. The mean JOA and ODI scores were 8.09 ± 1.44 and 55.47 ± 11.91. The mean preoperative pelvic incidence (PI) and lumbar lordosis (LL) angles were 51.02° ± 7.21 and 38.26° ± 6.98 and the mean PI-LL mismatch was 12.76° ± 5.63. There was no significant difference in the VAS scores for back/leg pain between the groups at 1 week after the operation, but the scores of the ES group were significantly higher than those of the MS group at 3 months and 12 months. There were no significant differences of mean JOA and ODI between the ES and MS groups preoperatively, at 3 months, or at 12 months, but the JOA and ODI scores of the ES group were significantly higher than those of the MS group 1 week after the operation. LIMITATIONS: The study showed that a novel method for the minimally invasive treatment of ADS is feasible; the safety and outcomes of this method should be verified with more cases. CONCLUSIONS: Minimally invasive decompression with a 10-mm endoscope was suggested to be a safe and effective method, as expected, for the treatment of lumbar stenosis in ADS patients. KEY WORDS: Adult degenerative scoliosis, endoscope, lumbar stability, microscopic decompression, minimally invasive