Study Design Retrospective study.Objective To assess the learning curve of microendoscopic decompression surgery for lumbar spinal canal stenosis (LSCS).Methods Four hundred eighty LSCS cases involving 753 stenotic lesions limited to the intraspinal canal were treated with microendoscopic decompression by a single surgeon at an institution between November 2006 and January 2015. They were numbered chronologically, and the operating time, intraoperative blood loss, and perioperative complications were investigated. Surgical outcomes were evaluated using the Japanese Orthopedic Association (JOA) score for low back pain before and 1 year after the operation.Results The mean operating time per level was 66.1 minutes. There was a progressive reduction in the operating time through the case series, and the approximate curve seemed to be y =  − 9.4Ln(x) + 115.0. The blood loss per level, which showed a mean value of 15.0 mL, was more than 50 mL in only 2.7% of the cases after case no. 30 and in 20% of the cases before it. There were 10 (2.1%) cases of perioperative complications, which occurred even after the surgeon had gained mastery of the procedure. The median JOA score improved significantly from 17 points preoperatively to 26 points postoperatively.Conclusions The learning curve of microendoscopic decompression surgery for LSCS has been defined with data for a single surgeon in an institution. The operating time seems to decrease along a natural logarithmic function. The intraoperative blood loss stabilizes after the first 30 cases, whereas perioperative complications can occur at any time even after mastery of the technique.

The objective of this study was to evaluate the efficacy of a microendoscopic spinal decompression surgical technique using a novel approach for the treatment of lumbar spinal canal stenosis (LSCS). The following modifications were made to the conventional microendoscopic bilateral decompression via the unilateral approach: the base of the spinous process was first resected partially to secure a working space, so as not to separate the spinous process from the lamina. The tip of the tubular retractor was placed at the midline of the lamina, where laminectomy was performed microendoscopically. A total of 126 stenotic levels were decompressed in 70 patients. The mean operating time per level was 77.0 minutes, and the mean intraoperative blood loss per level was 15.0 mL. There were no dural tears or neurological injuries intraoperatively. Fracture of the spinous process was detected postoperatively in two patients, both of whom were asymptomatic. All patients could be followed up for at least 12 months. Their median Japanese Orthopaedic Association (JOA) score improved significantly from 16 points preoperatively to 27.5 points after the surgery (p < 0.001). The case series showed that the modifications of the technique improved the safety and ease of performance of the microendoscopic decompression surgery for LSCS.

Study Design: Retrospective cohort study. Objectives: To investigate the effectiveness and safety of a gelatin–thrombin matrix sealant (GTMS) during microendoscopic laminectomy (MEL) for lumbar spinal canal stenosis (LSCS). Methods: This study included 158 LSCS cases on hemostasis-affecting medication who underwent MEL by a single surgeon between September 2016 and August 2020. Patients were divided into 2 groups depending on whether GTMS was used (37 cases, Group A) or not (121 cases, Group B). Perioperative data related to bleeding or postoperative spinal epidural hematoma (PSEH) was investigated. Clinical outcomes were evaluated using the Japanese Orthopedic Association (JOA) score for low back pain. Results: The mean intraoperative blood loss per level was greater in Group A (26.0 ± 20.3 g) than in Group B (13.6 ± 9.0 g), whereas the postoperative drainage volume was smaller in Group A (79.1 ± 42.5 g) than in Group B (97.3 ± 55.6 g). No revision surgeries for PSEH were required in Group A, while 2 (1.7%) revisions were required in Group B ( P = .957). The median JOA score improved significantly from the preoperative period to 1-year postoperatively in both Group A and B (total score, 16.0-23.5 and 17.0-25.0 points, respectively). Conclusions: The use of GTMS during MEL for LSCS may be associated with a reduction in postoperative drainage volume. The revision rate for PSEH was not affected significantly by the use of GTMS. Clinical outcomes (represented by the JOA score) were significantly improved after the surgery, regardless of GTMS use during MEL.

TD is a safe and effective surgical approach for the treatment of recurrent lumbar disc herniation. Operative time, intraoperative blood loss, and clinical results compare favorably with MED.

Study Design: Case series. Objectives: To report the clinical outcomes of the decompression procedure using the microendoscopic discectomy system for the treatment of a separation of lumbar posterior ring apophysis in young active athletes. Methods: We retrospectively reviewed 17 cases that underwent the microendoscopic surgery to treat a symptomatic separated lumbar ring apophysis between 2001 and 2014 at our institute or our associated hospital. The cases consisted of 15 males and 2 females, with their ages ranging from 12 to 19 years. The surgeries were performed at total of 18 lumbar levels, including 15 L4/5 and 3 L5/S1 levels. All patients were young athletes. We evaluated the following: (1) the Japanese Orthopaedic Association (JOA) score for low back pain, (2) recovery rates using Hirabayashi’s method, (3) operating time, (4) intraoperative blood loss, (5) perioperative complications, (6) the status of comeback to sports, and (7) the period taken to return to sports. Results: The JOA score was improved after the surgery in all cases. Recovery rate was 92.0% ± 8.1%. The mean operating time per level was 89.2 ± 33.3 minutes. The mean intraoperative blood loss per level was 95.3 ± 93.1 mL. A pinhole size dural tear occurred in one case as a perioperative complication. All cases returned to sports. The mean period taken to return to sports was 10.9 ± 3.5 weeks. Conclusion: Microendoscopic decompression surgery is useful for treating a separation of lumbar posterior ring apophysis.