After posterior cervical arthrodesis, many problems can arise, including adjacent segment degeneration and the related adjacent segment disease (ASD). As indicated by studies on the causes of ASD, posterior cervical arthrodesis can produce biomechanical and kinematic changes in adjacent unfused segments due to inappropriate forces. Several studies have been conducted to determine the appropriate lowest instrumented vertebra, specifically regarding whether to cross the cervicothoracic junction via extension of long-segment posterior cervical fusion. We searched for relevant articles in electronic databases including PubMed, the Cochrane Registry, Embase, and Ovid. Five meta-analyses were reviewed on this topic. Among these, Goyal et al. (2019), Rajjoub et al. (2022), and Chang et al. (2022) argued that ending instrumentation at the cervical level was associated with higher rates of ASD and reoperation. However, Truumees et al. (2022) and Coban et al. (2022) found no statistically significant differences between cases of instrumentation ending at the cervical and thoracic levels in the rates of ASD and requirement of revision surgery. Cervicothoracic junction breakage is a known possibility after cervical spine surgery because of the anatomical fragility of the junction. Terminating at the thoracic level reduces the stress on the cervicothoracic junction, thereby decreasing complications such as cervicothoracic junction breakage and lowering the frequency of reoperation. Based on the findings published to date, instrumentation across the cervicothoracic junction can be reasonably recommended in cases of multilevel posterior cervical fusion based on the lower reoperation and higher fusion rate.

Purpose
To analyze the serial change of the cervical saggital alignment especially cobb angle from immediately post operation to 3 month of post operation, and evaluate the effect of anatomically designed pillow to restore cervical lordosis.
Materials and Methods
cervical cobb angle (C2-C7) was measured in 38 patients whose radiographs at immediately post op, post op 1mo and post op 3mo were completely equipped. The patient group consisted of 10 patients in the general pillow group, 19 patients in the cervical pillow group, and 9 patients in the Philadelphia orthosis group.
Results
There was no statistically significant difference between the two groups using any pillow and the group using Philadelphia orthosis. Among them, patients who used anatomically designed pillow for 1 month to 3 months postoperatively were more likely to have lordotic change than the other patients, though it was not statistically significant.
Conclusion
The use of a cervical orthosis until the first month after the operation and subsequently anatomically degsined pillow for up to 3 months may be considered as a way to maintain lordotic curvature and prevent kyphotic changes.

Purpose
To analyze the risk of a fall in patients with cervical spondylotic myelopathy (CSM) and its clinical significance.
Materials and methods
40 patients with CSM who visited to our hospital From May 2014 to April 2015 were enrolled in this study. After confirmation of CSM based on MRI and Physical examination, patients were divided into three groups according to m-JOA score (Group A; severe; score <8, Group B; moderate; score 8-12, Group C; mild score >13). All patients enrolled in this study performed 4 functional assessment test including Alternative-Step Test (AST), Six-MeterWalk Test (SMT), Sit-to-Stand test (STS), and Timed Up and Go test (TUGT) to assess the risk of a falls (ROF).
Results
There were statistical significance between m-JOA score and ROF except for SMT. Average time (seconds) for STST was 26.12±5.60, 20.99±5.92 and 15.37±3.41 in group A, B, C, respectively (p=0.001), Although average time(s) for AST was 16.81±3.83, 14.39±4.05 and 12.37±3.95 in group A, B, C with no statistical significance (p=0.106), there was a significance between the value of Group A and C (p=0.047). Average time(s) for TUGT was 31.86±17.05, 15.09±4.59,18.04±9.32 in group A, B, C, respectively, showed statistical significance (p=0.000).
Conclusion
According to its severity of myelopathy, it took more time to carry out each ROF assessment tests. Among 4 functional assessment tests of ROF, STST showed the most highest correlation with mJOA socre. Careful attention of ROF will be needed in patients with myelopathy.

Lumbar cortical screw, an alternative to the traditional pedicle screw, has more cranially and laterally oriented trajectory within pedicle after being anchored in the pars interarticularis. Such cortical trajectory can lower the risk of nerve root impingement by traditional pedicle screw and reduce the iatrogenic soft tissue damage that occurs with muscle stripping and lateral retraction for traditional trajectory. In addition, lumbar cortical screw proved equivalent pullout strength compared with the traditional pedicle trajectory despite its shorter and smaller screw design. However, clinical trial is still in the beginning stage, and further clinical studies are required to clarify the actual outcome of the lumbar cortical screw.

Purpose
To find the factors that affecting surgical outcome after vertebroplasty and kyphoplasty in osteoporotic compression fracture.
Materials and Methods
Pre-operative, post-operative, technical, radiological factors of patients who diagnosed osteoporotic compression fracture and treated with vertebroplasty or kypholasty during from January 2008 to December 2010, were compared by outcomes that acute and chronic back pain, refracture rate and maintenance of the reduction of body height.
Results
The period of acute pain after the operation was less than 3 days in groups of trauma( p=0.0262) and hospital treatment(p=0.0113) before the operation as pre-operative factors. When it comes to technical factors, the cases of vertebroplasty(p<0.0001), injection of cement(p=0.0053), the case without leakage of cement(p=0.007) and the case being under anesthesia (p<0.005)achieved statistical significance. In the groups who got conservative treatment less than 1 week (p=0.0119) and local anesthetics(p=0.0246), refractures occurred many times. The groups of non-trauma(p=0.0105), having had more than 30% compression(p=0.0244) and the group that prescribed bisphosphonate(p=0.0286) statistical significantly maintained restoration.
Conclusion
Conservative treatment in the hospital for more than 1 week before the operation, operation being under anesthesia and intake of bisphosphonate after the operation put positive effects on the outcome of vertebroplasty and kyphoplasty.