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.

Background
Cervical kyphosis is frequently observed in the patients without axial neck pain and sigmoid curvatures are parts of the variety of cervical kyphosis. Purpose: This study was designed to investigate the characteristics of the static and dynamic alignment of the cervical spine with sigmoid configurations.
Methods
Figty patients without changes of the cervical curvatures after subsidence of axial neck pain were enrolled in this study. Based on the alignment of cervical spine on lateral radiographs, cervical alignments were classified: kyphotic (K), kypho-lordotic (KL), lordo-kyphotic (LK), and Lordotic (L) group. The sagittal alignment angles and each segmental angle were measured using the Harrison method on neutral, flexion, and extension-lateral radiographs.
Results
The mean ratio of segmental ROM to C2-7 ROM revealed a similar pattern across the cervical levels without statistical difference between the groups. In the KL and LK group, the linear graphs for the mean ratio of segmental angles to C2-7 angles in flexion and extension showed a mirror image with respect to the C4-5 level. The lordotic components of both curves demonstrated larger ratio of segmental angles in flexion than the kyphotic components. The kyphotic components of both curves demonstrated larger ratio of segmental angles in extension than the lordotic components.
Conclusions
The lordotic and kyphotic components regardless of the type of sigmoid curvatures seem to adhere to constant dynamic behavior during flexion and extension. Therefore, the KL and LK cervical alignments may have the opposite dynamic behaviors in the high and low cervical levels.

Purpose
To assess the volume of fusion mass after posterior lumbar interbody fusion (PLIF) using Hounsfield units methods.
Methods
The present study was within the frame work about a prospective observational cohort study to compare the surgical outcomes of a single-level PLIF for LSS between the local bone (LbG) and local bone plus hydroxyapatite groups (LbHa). The fusion material for each case was determined by the amount of available local bone. After the fusion material was chosen, patients were assigned to either the LbG group (n=20) or the LbHa group (n=20). The primary outcome was the assessment of fusion mass volume in each group.
Results
We used the new method using Hounsfield units for volumetric assessments of interbody fusion mass. There was no difference in fusion rates or volume of the fusion mass between the 2 groups.
Conclusions
Hounsfield unit method, that is the CT-based summation method using a cross-sectional slice, can be applied usefully to other areas of orthopaedics.

Purpose
To evaluate the method of inserting cortical bone trajectory pedicle screws (cortical screws) and potential complications when performing lumbar fusion.
Methods
Lumbar fusion with cortical screw fixation in the hard cortical bone of the pars interarticularis of vertebrae was introduced to replace conventional pedicle screws. We review the literature on the biomechanics of cortical screw insertion and on the clinical outcomes.
Results
In vitro biomechanical testing has shown that cortical screws have greater pullout strength than traditional pedicle screws due to the strong bone–screw interface in cortical bone. Cortical screws have the advantages of requiring minimal muscle dissection and shortening the surgery. However, early screw loosening and loss of reduction have been reported.
Conclusions
When inserting cortical screws, the entry point and trajectory of the screws are important and a meticulous surgical technique is needed to prevent potential screw-related complications.

Although metastatic lung adenocarcinoma in the spinal cord is rare, it can be diagnosed by positron emission tomography and computed tomography (PET/CT) scan with high sensitivity during the early disease stage. A clinical and radiographic review was performed to present a rare case of an intradural intramedullary adenocarcinoma metastasis in the spinal cord with a negative PET/CT scan. A 75-year-old man with a diagnosis of lung cancer without metastasis confirmed by a negative PET/CT scan with no spinal symtoms (conducted 6 weeks previously) presented with progressive paralysis of both lower extremities and accompanying bowel and bladder symptoms. He underwent radical lobectomy of left lung under diagnosis of lung cancer without distant metastasis 6 weeks ago. Emergent MRI was performed, and MRI revealed a large intradural intramedullary mass compressing the spinal cord and extending from T12 to L1 with anterior compression of the spinal cord. Surgical decompression and tumor resection from T12 to L1 by lumbar laminectomy and durotomy were performed under a microscope. And, a diagnosis of adenocarcinoma to the spinal cord was made based on histopathologic findings. Postoperatively, the patient’s neurologic status was not significantly improved. Despite a negative PET/CT scan finding with no neurologic symptoms or pain, surgeons should not exclude the possibility of a spinal metastatic lesion with lung cancer.