Purpose
The purpose of this retrospective study was to evaluate the results and complications of lateral mass screw fixation on C7 in a single spinal center.
Materials and Methods
During a 7-year period, a total of 104 lateral mass screws were placed on C7 in 56 patients with cervical disorders. A review of the hospital records and radiographs of these patients was conducted. Followup plain X-rays and computed tomography (CT) including sagittal reconstruction were obtained to analyze screw positions.
Results
A total of 104 screws were placed on C7 lateral mass using the modified Magerl’s method. Most patients had two screws on both lateral masses, but eight underwent unilateral lateral mass screw fixation due to fracture (n=4), lateral mass deficit due to tumor removal (n=1), and unilateral fixation for additional stabilization of an anterior fixation (n=3). Most cases were connected to the subaxial spine (91.1%). All patients underwent more than 1 year of follow-up. The only complication was one wound infection. On follow-up CT, one transverse foramen invasion (2 mm), one spinal canal invasion, and four facet joint violations developed post-operatively. However, no symptoms related to these issues were occurred, so reoperations for instrument repositioning were not required. Screw loosening and pseudoarthrosis did not develop during the follow-up period. Also, there was no case of vertebral artery or neural injury requiring reoperation due to the position of the lateral mass screw. Almost patients showed successful bone fusion on follow-up images, with the exception of one patient.
Conclusion
Despite the small size of the lateral mass, risk of pseudoarthrosis, and steep angle of the lamina, lateral mass screw fixation can be a safe, easy and less complicated method of posterior cervical stabilization. If the lateral mass is suitable, lateral mass screw fixation may enable C7 stabilization during posterior subaxial cervical surgery.

Purpose
The purpose of this review is the current understanding of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) following adult spinal deformity (ASD) surgery.
Materials and Methods
We carried out a systematic search of PubMed for literatures published up to September 2016 with “proximal junctional kyphosis” and “proximal junctional failure” as search terms. A total of 57 literatures were searched. Finally, the 33 articles were included in this review.
Result
PJK and PJF are recognized complications after long instrumented posterior fusion in ASD surgery. PJK is multifactorial in origin and likely results from surgical, radiographic, and patient related risk factors. PJF is a progressive form of the PJK spectrum including bony fracture of uppermost instrumented vertebra (UIV) or UIV+1, subluxation between UIV and UIV+1, failure of fixation, neurological deficit, which may require revision surgery for proximal extension of fusion. Variable risk factors for PJK and PJF have been investigated, and they can be categorized into surgical, radiographic, and patient-related factors. There are several strategies to minimize PJK and PJF. Soft tissue protections, adequate selection of the UIV, prophylactic rib fixation, hybrid instrumentation such as hooks, vertebral cement augmentation at UIV and UIV+1, and age-appropriate spinopelvic alignment goals are worth consideration.
Conclusion
The ability to perform aggressive global realignment of spinal deformities has also led to the discovery of new complications such as PJK and PJF. Continuous research on PJK and PJF should be proceeded in order to comprehend the pathophysiology of these complications.

Objective
The aim of this study was to analyze significant motion predictors in patients with discogenic and facetogenic back pain confirmed by diagnostic injections and to see confounders which influence motion predictors.
Methods
Medial branch block and epidural steroid injection were used for facetogenic and discogenic midline pain. Transforaminal epidural steroid injection was selected for discogenic lateralized back pain. Positive response was defined as over 75% pain relief. Sixty-four patients (facetogenic pain, 45 bilateral or 9 unilateral, 82% pain relief ), Sixty-three patients (discogenic midline pain, 83%), and twenty-three patients (discogenic lateralized pain, 85%) had been enrolled prospectively in one institution between June 2010 and October 2013. Motion provocation tests were conducted during standing, sitting, flexion, extension, lateral bending, rotation, and extension with rotation for the detection of motion predictors. A self-weighted grade system was applied for pain provocation. Confounders such as age, sex, facet joint degeneration, flexion pain, grade of protrusion, circumferential annular tear, transverse annular tear, and spino-pelvic parameters were assessed to find the influence on motion predictors.
Results
In patients with facetogenic pain, pain provocation was prominent during standing (p=0.006), extension (p=0.052), rotation (p=0.000), and extension with rotation (p=0.000). In those with discogenic midline pain, more pain generated during flexion (p=0.000) and sitting (p=0.044). The difference in spino-pelvic parameters between two pain groups was not observed. The difference between discogenic midline and lateralized pain occurred during flexion (midline, p=0.046) and lateral bending (lateralized, p=0.057). Similarly, flexion (p=0.068) and lateral bending (p=0.067) might be also insignificant but helpful predictors to differentiate discogenic lateralized pain from facetogenic lateralized pain. For facetogenic pain, there were significant confounders as follows; standing (facet capsule enhancement, pelvic incidence), sitting (sex), extension (spino-pelvic parameters), lateral bending (pelvic tilt), rotation (age, sex, arthritis, facet capsule enhancement, pelvic tilt). Extension with rotation showed relatively less changes. For discogenic pain, a lake type circumferential tear generated less flexion pain and more extension pain. A superior transverse tear influenced sitting, extension, and lateral bending. A protrusion without a transverse tear increase flexion pain. Higher pelvic incidence and pelvic tilt generated more extension and extension with rotation pain. Among motions, sitting was not influenced by most probable confounders.
Conclusion
Predictors of facetogenic pain were extension with rotation, rotation, standing, extension, and lateral bending in order of probability. Flexion and sitting may be predictors of discogenic midline pain. Flexion and lateral bending may be predictors favoring discogenic lateralized pain compared with facetogenic pain. However, these motions may be vulnerable to parameters such as age, sex, facet arthritis, facet enhancement, circumferential or transverse tear, and spino-pelvic parameters. Considering the confounders’ effect, predictors were likely to be extension with rotation for facetogenic pain, sitting for discogenic midline pain, flexion and lateral bending for discogenic lateralized pain compared with facetogenic pain. These points should be considered in making a diagnosis during the physical examination in the outpatient clinic.

Background
Owing to its new introduction, there are few documents on pit-falls of biportal endoscopic spine surgery (BESS) clinically. The authors reported etiologies in need of early exploration after BESS for lumbar degenerative diseases and strategies to overcome them.
Methods
BESS were performed for lumbar spine diseases (LSDs) by two spine surgeons from December 2013 to March 2016. Postoperative MRI was checked for all cases and following-up MRIs in the case in need of revision surgery within six months after the first surgery due to pain intolerable, sustained or recurred. The complicated cases were reviewed and classified as radiographic and operative findings to reveal the main reasons for early explorations.
Results
The 562 cases (M:295, F:267, Age 58.5±14.1 yrs, 20~88 yrs) included lumbar disc herniation (LDH) (255 cases), extraforaminal disc herniation (22 cases), spinal stenosis (218 cases), degenerative spondylolisthesis (27 cases), revision surgery after recurred disc herniation or restenosis after open surgery (24 cases), juxtafacet cyst (11 cases), adjacent segment stenosis with fusion surgery (3 cases), and spondylolytic spondylolisthesis (2 cases). Early explorations were needed in 43 cases (7.7%) at 26.1±31.5 days after the initial operations. Causative etiologies were listed as recurred LDH (12 cases, 27.9%), remnant stenosis (7 cases, 16.3%), remained ruptured disc fragment (6 cases, 14.0%), root edema (5 cases, 11.6%), synovitis (4 cases, 9.3%), hematoma (3 cases, 7.0%), dura tear (2 cases, 4.7%), recurred stenosis (2 cases. 4.7%), wrong level (1 case, 2.3%) and postoperative fungal infection (1 case, 2.3%). Thirty-one cases (72.1%) were revised within 4 weeks and most conditions (40 cases, 93.0%) were improved after early exploration using BESS. Two cases of dura tear were conversed to open repair. One case of fungal infection was suspected to related with the patient’s medical illness including long-term steroid use for chronic lung disease with pulmonary fibrosis and Diabetes mellitus.
Conclusions
Preoperative planning should be prepared carefully to decrease early exploration. It was helpful to comparing MRIs immediately postoperative and early following-up to find the reasons. Don’t hesitate to explore the operated site again using BESS, because most etiologies are supposed to be controlled by early exploration without need of converting to open surgery except in the case of dura tear in need of dural repair.

Seventy-five-year female patient with diabetes, hypertension and hyperthyroidism visited our clinic for left shoulder radiating pain. In cervical radiologic study, multiple nodules were seen on both lung fields. In chest MDCT, active pulmonary tuberculosis and miliary tuberculosis were suspected and mass on 1st and 2nd thoracic vertebral body with destruction was seen. In cervico-thoracic MRI, 1st thoracic vertebral pathologic fracture was found. Miliary tuberculosis with spinal tuberculosis was diagnosed with right middle lobe biopsy. After 3 weeks with chemotherapy, lesion got advanced on MRI and radiating pain got worse. We performed 1st thoracic vertebral corpectomy with auto iliac bone graft, after 1 week posterior instrumentation was performed. After surgery, radiating pain and weakness got better, the patient is followed up at the outpatient. In general, spinal tuberculosis treats with antituberculous agent at first. But, if spinal deformity or neurologic symptom was accompanied, surgical correction will be necessary. In this case, advanced cervico-thoracic spinal tuberculosis with conservative therapy was treated 1st thoracic vertebral corpectomy with auto iliac bone graft and posterior instrumentation. The patient’s neurologic symptom was got better after surgery.