Background
Percutaneous-short segment screw fixation (SSSF) without bone fusion has proven to be a safe and effective modality for thoracolumbar spine fractures (TLSFs). When fracture consolidation is confirmed, pedicle screws are no longer essential, but clear indications for screw removal following fracture consolidation have not been established.
Methods
In total, we enrolled 31 patients with TLSFs who underwent screw removal following treatment using percutaneous-SSSF without fusion. Plain radiographs, taken at different intervals, measured local kyphosis using Cobb’ angle (CA), vertebra body height (VBH), and the segmental motion angle (SMA). A visual analogue scale (VAS) and the Oswestry disability index (ODI) were applied pre-screw removal and at the last follow-up.
Results
The overall mean CA deteriorated by 1.58º (p<0.05) and the overall mean VBH decreased by 0.52 mm (p=0.001). SMA preservation was achieved in 18 patients (58.1%) and kyphotic recurrence occurred in 4 patients (12.9%). SMA preservation was statistically significant in patients who underwent screw removal within 12 months following the primary operation (p=0.002). Kyphotic recurrence occurred in patients with a CA ≥20º at injury (p<0.001) with a median interval of 16.5 months after screw removal. No patients reported worsening pain or an increased ODI score after screw removal.
Conclusion
Screw removal within 12 months can be recommended for restoration of SMA with improvement in clinical outcomes. Although, TLSFs with CA ≥20º at the time of injury can help to predict kyphotic recurrence after screw removal, the clinical outcomes are less relevant.

Purpose
Minimally invasive technique in spinal surgery have evolved including cortical bone trajectory (CBT) screw technique which is s new lumbar pedicle screw path, as an alternative fixation technique for lumbar spine. Theoretical advantage is that it provides enhanced screw torque and has biomechanical characteristics, also it minimizes approach-related damages. Midline lumbar fusion (MIDLF) has appeared with CBT screw technique. Many studies of CBT screw reported the effectiveness of MIDLF. We adopted this technique for lumbar degenerative spondylolisthesis and evaluated early radiological outcomes.
Materials and Methods
From May 2014 to March 2015, 17 patients (mean age 65.6±7.5 years; 4 males, 13 females) underwent MIDLF procedures for the treatment of single level lumbar spondylolisthesis. Average follow-up period was 8.8±2.7 months. Initial and last follow-up X-ray and computed tomography (CT) were evaluated for screw malposition, detection of peri-screw halo, loosening of the construct, or signs of spinal instability.
Results
The average bone mineral density (BMD) was -1.9±0.8. Eleven patients were fused at L4-5, 5 were at L3-4, and 1 was at L2-3. Five CBT screws were converted into pedicle screws due to intraoperative misposition of screws, so total 63 CBT screws were evaluated for peri-screw halo and malposition. There were no findings of screw pull-out or breakage in all screws. Four out of 63 (6.3%) screws were judged as peri-screw halo, and 20 (41.2%) screws were judged as malposition (1 medial; 2 superior; 17 lateral pedicle violation). But, there were no screw related nerve root injury. In all cases, interbody bony mass were identified. Four out of 17 (23.6%) patients were detected more than 2 degrees motions on flexion-extension lateral X-rays at final follow-up, and 1 out of these 4 patients was identified loss of reduction. There was no operation related complication.
Conclusion
There is no doubt that MIDLF with CBT screw is the minimally invasive method. Many numbers of screw malposition identified in our series were thought to be due to our earlier experience of trying free hands technique. We recommend the use of intraoperative fluoroscopy, which achieve accuracy. Although MIDLF with CBT has theoretical strengths, we must evaluate further long-term clinical follow-up and measure outcome.

Purpose
To evaluate the impacts of regional and socioeconomic factors on adolescent idiopathic scoliosis (AIS) diagnosis and treatment using national datasets of the Korean National Health Insurance System. The prevalence of, and therapeutic trends in, AIS are affected by a variety of environmental factors.
Materials and Methods
We analyzed random samples from datasets (10% of all entries) between 2012 and 2018, including in terms of patient demographics, residential status (a “special city”, and urban, and rural regions) and socioeconomic status (SES) based on health insurance premiums (which distinguish National Health Insurance and Medical Aid [MA] beneficiaries).
Results
The AIS prevalence was approximately 1.6-fold higher in females than in males, whereas the rate of male surgery was approximately 1.5-fold higher than that in females. AIS prevalence was higher among National Health Insurance beneficiaries (in all years), whereas the surgery rate was higher among MA beneficiaries (in most years). In all years, AIS prevalence was significantly higher among special city residents than in urban and rural residents. However, the surgical treatment rates were higher in the latter regions.
Conclusions
Our nationwide evaluation revealed AIS prevalence rates and therapeutic trends. AIS epidemiology varies by region and economic status.

Background
Endoscopic surgery has demonstrated its effectiveness against disc herniations. However, there are limitations in its use in removing a highly up-migrated lumbar disc in hidden zone. This study aimed to introduce the biportal endoscopic approach for the treatment of a highly up-migrated lumbar disc and to report the preliminary surgical outcomes.
Methods
This study included 28 patients with a highly up-migrated lumbar disc who underwent biportal endoscopic surgery through one-level above contralateral corridor for disc removal. Patients were re-evaluated by postoperative MRI to confirm the successful removal of ruptured fragments. Simple X-ray was obtained for assessing the development of spinal instability. Back and leg pain were evaluated using Visual Analog Scale (VAS) scores. The satisfaction rate of clinical outcomes was assessed using the modified MacNab criteria.
Results
The mean age of patients was 62.3 years, and the mean follow-up period was 21.4 months. Compared to preoperative scores, VAS scores of back and leg pain significantly improved. At the final follow-up, two patients had unfavorable outcome due to the presence of residual leg pain. There was no new development of segmental instability or spondylolisthesis.
Conclusions
Biportal endoscopic approach with one-level above contralateral corridor may be an alternative treatment method for a highly up-migrated lumbar disc, with advantages including direct visualization of the hidden zone from the tail of ruptured fragment to the ruptured site, preservation of the facet joint and pars interarticularis.