ABSTRACT
Objective To analyze the learning curve of microendoscopic lumbar discectomy (MED) and summarize the operative experience. Methods From July 2010 to March 2012, the first 100 patients with single level lumbar disc herniation managed with MED were divided into chronological groups (A, B, C and D), 30 patients in group A, B, C and 10 patients in group D. The comparsons were conducted in terms of operative time , estimated blood loss , number of cases with transition from MED to open surgey or for reoperation , rate of complications and postoperative efficacy. Results The mean operative time and the mean estimated blood loss in each group was valuated respectively. In group A , the operative time and estimated blood loss were significantly decreased as compared with those in group B, C and D respectively (P 0.05). There were 6 complications in group A, 1 complication in group B and C respectively and no complication in group D. The leg pain visual analogue scale and Oswestry disability index at the first month and the twelfth month postoperatively were all improved respectively as compared with those preoperatively (P < 0.01). Conclusion The learning curve of microendoscopic lumbar discectomy generally may reach the plateau when about 30 cases are operated on. The key procedure to pass over the learning curve includes puncture and location , flavectomy , anatomy mark identification, and precaution of damage in dural sac.
ABSTRACT
BACKGROUND: To describe and assess clinical outcomes of the semi-circumferential decompression technique for microsurgical en-bloc total ligamentum flavectomy with preservation of the facet joint to treat the patients who have a lumbar spinal stenosis with degenerative spondylolisthesis. METHODS: We retrospectively analyzed the clinical and radiologic outcomes of 19 patients who have a spinal stenosis with Meyerding grade I degenerative spondylolisthesis. They were treated using the "semi-circumferential decompression" method. We evaluated improvements in back and radiating pain using a visual analogue scale (VAS) and the Oswestry Disability Index (ODI). We also evaluated occurrence of spinal instability on radiological exam using percentage slip and slip angle. RESULTS: The mean VAS score for back pain decreased significantly from 6.3 to 4.3, although some patients had residual back pain. The mean VAS for radiating pain decreased significantly from 8.3 to 2.5. The ODI score improved significantly from 25.3 preoperatively to 10.8 postoperatively. No significant change in percentage slip was observed (10% preoperatively vs. 12.2% at the last follow-up). The dynamic percentage slip (gap in percentage slip between flexion and extension X-ray exams) did not change significantly (5.2% vs. 5.8%). Slip angle and dynamic slip angle did not change (3.2° and 8.2° vs. 3.6° and 9.2°, respectively). CONCLUSIONS: The results suggested that semi-circumferential decompression is a clinically recommendable procedure that can improve pain. This procedure does not cause spinal instability when treating patients who have a spinal stenosis with degenerative spondylolisthesis.