Jae-Sung Ahn

Extraforaminal approach of biportal endoscopic spinal surgery: a new endoscopic technique for transforaminal decompression and discectomy

This study was performed to describe the extraforaminal approach of biportal endoscopic spinal surgery (BESS) as a new endoscopic technique for transforaminal decompression and discectomy and to demonstrate the clinical outcomes of this new procedure for the first time. Twenty-one patients (27 segments) who underwent the extraforaminal approach of BESS between March 2015 and April 2016 were enrolled according to the inclusion and exclusion criteria. The operative time (minutes/level) and complications after the procedure were recorded. The visual analog scale (VAS) score was checked to assess the degree of radicular leg pain preoperatively and at the time of the last follow-up. The modified Macnab criteria were used to examine the clinical outcomes at the time of the last follow-up. The mean duration of the follow-up period was 14.8 months (minimum duration 12 months). The mean operative time was 96.7 minutes for one level. The mean VAS score for radicular leg pain dropped from a preoperative score of 7.5 ± 0.9 to a final follow-up score of 2.5 ± 1.2 (p < 0.001). The final outcome according to the modified Macnab criteria was excellent in 5 patients (23.8%), good in 12 (57.2%), fair in 4 (19.0%), and poor in 0. Therefore, excellent or good results (a satisfied outcome) were obtained in 80.9% of the patients. Complications were limited to one dural tear (4.8%). The authors found that the extraforaminal approach of BESS was a feasible and advantageous endoscopic technique for the treatment of foraminal lesions, including stenosis and disc herniation. They suggest that this technique represents a useful, alternative, minimally invasive method that can be used to treat lumbar foraminal stenosis and disc herniation.

Comparison between Radiological and Clinical Outcomes of Laminoplasties with Titanium Miniplates for Cervical Myelopathy

Background Laminoplasty is a surgical procedure frequently performed for cervical myelopathy. We investigated correlations between changes in the anteroposterior diameter (APD) of the spinal canal, spinal canal area (SCA), and laminar angle (LA) and clinical outcomes of laminoplasty. Methods Of the 204 cervical myelopathy patients who underwent laminoplasty from July 2010 to May 2015, 49 patients who were evaluated with pre- and postoperative computed tomography of the cervical vertebrae were included. The average age of the patients was 60.4 years (range, 31 to 82 years), and the average duration of follow-up was 31.6 months (range, 9 to 68 months). Changes in the APD and SCA were measured at the middle of the vertebral body. Changes in LA were measured where both pedicles were clearly visible. Clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA) score and visual analog scale score for pain preoperatively (1 day before surgery) and postoperatively (last outpatient visit) and examining postoperative complications. Results The APD showed an average of 54.7% increase from 11.5 to 17.8 mm. The SCA showed an average of 57.7% increase from 225.9 to 356.3 mm2. The LA increased from 34.2° preoperatively to 71.9° postoperatively. The JOA score increased from an average of 9.1 preoperatively to 13.4 postoperatively. Three patients were found to have hinge fractures during surgery. Postoperative complications, including two cases of C5 palsy, were recorded. The correlation coefficient between the LA change and JOA score improvement was −0.449 (p < 0.05). Patients with a < 33° (25%) increase in the LA showed the most significant clinical improvement. Conclusions Patients with a < 33° (25%) change in the LA after laminoplasty with a titanium miniplate showed the most significant clinical improvement. Thus, LA changes can be useful in predicting the clinical outcome of laminoplasty.