Background and Objectives: Lumbar disc degeneration (LDD) is the main cause of lower back pain and leads to corresponding disc height loss. Although lumbar interbody fusion (LIF) is commonly used for treating LDD, several different treatment strategies are available. We performed a minimally invasive full-endoscopic LIF (FELIF) using a uniportal full-endoscopic system. Materials and Methods: FELIF was performed for 12 patients with LDD with disc-height loss using a 4.1 mm working channel endoscope and a newly developed slider for cage insertion. The mean age of the patients was 68.3 years; the patients presented with single vertebral level involvement. The Brandner’s disc index was used for evaluating the postoperative increase in the disc height. Preoperative and postoperative leg pain was evaluated using the numerical rating scale (NRS) score. Results: The mean operation time for FELIF was 109.4 min. The mean duration of hospital stay after FELIF was 7.7 days. There were no operative and postoperative complications, even without drainage during the mean follow-up period of 6.2 months (range, 2–10 months). The Brandner’s disc index improved statistically significant (p > 0.01). The mean preoperative and postoperative NRS scores were 6.5 and 1.2, respectively. Conclusions: FELIF using a 4.1 mm working channel endoscope can be used for treating LDD with disc height loss. Radiculopathy caused by foraminal stenosis was the most suitable operative indication for FELIF.

Background: Posterior pedicle screw fixation without fusion has been commonly applied for thoracolumbar burst fracture. Implant removal is performed secondarily after bone union. However, the occurrence of secondary kyphosis has recently attracted attention. Secondary kyphosis results in poor clinical outcomes. The purpose of this was to determine predictors of kyphosis after implant removal following posterior pedicle screw fixation without fusion for thoracolumbar burst fracture. Methods: This retrospective study reviewed 59 consecutive patients with thoracolumbar burst fracture who underwent implant removal following posterior pedicle screw fixation without fusion. Inclusion criteria were non-osteoporotic fracture and T11-L3 burst fracture. Old age, sex, initial severe wedge deformity, initial severe kyphosis, and vacuum phenomenon were examined as factors potentially associated with final kyphotic deformity (defined as kyphotic angle greater than 25°) or loss of correction. Logistic regression analysis was performed using propensity score matching. Results: Among the 31 female and 28 male patients (mean age 38 years), final kyphotic deformity was found in 17 cases (29%). Multivariate analysis showed a significant association with the vacuum phenomenon. Loss of correction was found in 35 cases (59%) and showed a significant association with the vacuum phenomenon. There were no significant associations with other factors. Conclusions: The findings of this study suggest that the vacuum phenomenon before implant removal may be a predictor of secondary kyphosis of greater than 25° after implant removal following posterior pedicle screw fixation without fusion for thoracolumbar burst fracture, but that old age, sex, initial severe kyphosis, and initial severe wedge deformity may not be predictors.

Background and Objectives: Full-endoscopic cervical foraminotomy (FECF) and microendoscopic cervical foraminotomy (MECF) are effective surgeries for cervical radiculopathy and are considered minimally invasive in terms of damage to paraspinal soft tissue. However, no studies have quantitatively compared FECF and MECF in terms of neurological invasiveness. The aim of this study was to compare the neurological invasiveness of FECF and MECF using intraoperative motor evoked potential (MEP) monitoring. Materials and Methods: A chart review was conducted of 224 patients with cervical radiculopathy who underwent FECF or MECF between April 2014 and March 2020. Patients were 37 women and 187 men, with a mean age of 51 (range, 21–86) years. FECF was performed in 143 cases and MECF was performed in 81 cases. Results: Average MEP amplitude significantly increased from 292 mV before to 677 mV after nerve root decompression in patients who underwent the FECF. The average improvement rate was 273%. In patients who underwent the MECF, average MEP amplitude significantly increased from 306 mV before to 432 mV after nerve root decompression. The average improvement rate was 130%. The improvement rate was significantly higher for FECF compared with MECF. Conclusions: MEP amplitude increased after nerve root decompression in both FECF and MECF, but the improvement rate was higher in FECF. These results suggest that FECF might be more minimally invasive than MECF in terms of neurological aspects.

Background: Posterior pedicle screw fixation without fusion has been commonly applied for thoracolumbar burst fracture. Implant removal is performed secondarily after bone union. However, the occurrence of secondary kyphosis has recently attracted attention. Secondary kyphosis results in poor clinical outcomes. The purpose of this was to determine predictors of kyphosis after implant removal following posterior pedicle screw fixation without fusion for thoracolumbar burst fracture.Methods: This retrospective study reviewed 60 consecutive patients with thoracolumbar burst fracture who underwent implant removal following posterior pedicle screw fixation without fusion. Inclusion criteria were non-osteoporotic fracture and T11-L4 burst fracture. Old age, sex, initial severe wedge deformity, initial severe kyphosis, and vacuum phenomenon were examined as factors potentially associated with final kyphotic deformity (defined as kyphotic angle greater than 25°) or loss of correction. Logistic regression analysis was performed using propensity score matching.Results: Among the 31 female and 29 male patients (mean age 39 years), final kyphotic deformity was found in 17 cases (28%). Multivariate analysis showed a significant association with the vacuum phenomenon. Loss of correction was found in 35 cases (58%) and showed a significant association with the vacuum phenomenon. There were no significant associations with other factors.Conclusions: The findings of this study suggest that the vacuum phenomenon before implant removal may be a predictor of secondary kyphosis of greater than 25° after implant removal following posterior pedicle screw fixation without fusion for thoracolumbar burst fracture, but that old age, sex, initial severe kyphosis, and initial severe wedge deformity may not be predictors.