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Study design Retrospective observational study. Objective This study aimed to determine the effect of reducing the radiation dose of intraoperative cone beam computed tomography (CBCT) during posterior spinal fusion (PSF) for pediatric scoliosis on the rate of pedicle screw (PS) violation. Summary of background data Intraoperative CBCT for pediatric scoliosis improves the accuracy of PS insertion in PSF. However, few reports have addressed the PS perforation rate from reduced radiation doses in hybrid navigation. Methods We evaluated 855 PSs inserted into 58 pediatric scoliosis patients (11 male and 47 female, mean age: 16.6 years) who underwent PSF using CBCT. A radiation dose of 1/3 or 1/5 of the normal dose (ND) was defined as a low dose (LD). After PS insertion, intraoperative CBCT images were reviewed to assess the degree of PS perforation. G2-3 (i.e., perforations of 4 mm or more) was defined as a violation. The PS violation rate was compared between the groups, and factors associated with violations were examined. Results A total of 567 and 288 screws were inserted in the ND group and LD group, respectively. The PS violation rate was comparable at 1.8% in the ND group and 1.7% in the LD group. Multiple logistic regression analysis showed that distance from the upper instrumented vertebra (UIV) was an independently associated factor of PS violation (+1 vertebra, OR 0.73, P = 0.038). In addition, the mean height of patients with PS violations (148.8 ± 3.6 cm) was significantly shorter than that of patients without violations (157.9 ± 1.2 cm) (P = 0.034). Conclusion There was no increase in PS violation rate with lower doses of radiation for intraoperative navigation CBCT. Extra care is warranted for vertebrae close to the UIV and patients of shorter stature.Level of Evidence: 3.

Study design Japanese resident cohort study based on a municipal registry. Objective This study of a community-dwelling elderly Japanese population employed random sampling from the basic resident registry of a rural town for subject selection to investigate the differences in bone mineral density (BMD) and bone turnover markers between subjects with and without diffuse idiopathic skeletal hyperostosis (DISH). Summary of background data DISH is a condition characterized by the calcification and ossification of soft tissues. Although some reports have addressed BMD in DISH, the precise status of BMD and bone metabolism in individuals with DISH remains unclear. Methods Eight groups based on age (50s, 60s, 70s, and 80s) and sex after random sampling from the resident registry of Obuse town were established. A total of 411 participants (202 males and 209 females) were enrolled for the evaluation of BMD and bone turnover markers. All subjects underwent a single whole-spine lateral radiographic examination for the existence of DISH. The BMD and bone turnover markers of subjects with and without DISH were analyzed for associations with the disorder using multivariate analysis. Results DISH was detected in 66 (16.1%) participants in our population cohort. According to multivariate analysis, increased lumbar and hip BMD were significantly related to DISH (odds ratio: 7.47 and 22.8, respectively). Conclusion This study clarified the differences in BMD and bone turnover markers between subjects with and without DISH on a general population basis. Multivariate analysis revealed increased lumbar and hip BMD to be significantly associated with DISH, with no remarkable findings for bone turnover markers. Level of evidence 4.

Study design Retrospective multicenter cohort study. Objective We evaluated a new upper instrumented vertebra (UIV) selection method that used the modified Shinshu line (MSL) to establish the selected UIV as the MSL vertebra (MSLV). Summary of background data No reports have addressed optimal UIV selection according to the lower instrumented vertebra (LIV) for good trunk balance in Lenke 1A curves. Methods Forty-five consecutive patients (44 female, 14.4 ± 2.4 yrs) receiving posterior spinal fusion (PSF) for a Lenke 1A adolescent idiopathic scoliosis (AIS) curve were analyzed. We defined the novel MSL as the line between the center of the spinous process of C7 and that of the spinous process of the LIV. The vertebral body with which the MSL first contacted proximally was defined as the MSLV. The groups in which the UIV was at, proximal to, or distal to the MSLV were defined as the matched group (M-group; 15 cases [15 female], 14.7 ± 2.1 yrs), proximal group (P-group; 20 cases, [19 female], 15.0 ± 2.2 yrs), and distal group (D-group; 10 case [10 female], 14.8 ± 2.5 yrs), respectively. We measured Cobb angle, main thoracic (MT) curve correction rate, and C7 plumb line absolute value (C7PL) at pre- and 2 years postoperatively for comparisons using Dunnett test, with the M-group as the control. Results In the M-group, P-group, and D-group, the Cobb angle correction rate between pre- and postoperative time points were 65.3 ± 1.3%, 62.4 ± 1.6%, and 52.8 ± 6.8%, respectively, and comparable apart from a smaller correction tendency in the D-group versus the M-group (P = 0.08). At 2 years postoperatively, C7PL was 0.5 ± 0.4, 1.0 ± 0.6, and 1.3 ± 0.9 cm, respectively, and significantly smaller for the M-group (both P Conclusion Better trunk balance were obtained without reducing correction rate by setting the novel MSLV as the UIV in PSF for Lenke type 1A curves. Level of evidence 3.

Study design Multicenter, prospective randomized study. Objective Evaluate the impact of weekly teriparatide (WT) and bone contact (BC) status of grafted bone in patients recovering from multilevel lumbar interbody fusion (M-LIF). Summary of background data WT has been reported to significantly improve bone fusion following posterior or transforaminal interbody fusion in osteoporosis patients. Methods Patients older than 50 years and osteoporotic were recruited. We defined the fusion of two or more consecutive intervertebral levels as M-LIF. All patients were instrumented with pedicle, iliac, or S-2 alar iliac screws after transplanting cages and autogenous bone between vertebral bodies. After surgical indication for M-LIF, the subjects were randomly allocated to receive either subcutaneous WT from 1 week to 6 months postoperatively (WT arm, N = 50) or a bisphosphonate (BP; BP arm, N = 54). Blinded radiological evaluations were performed using computed tomography (CT). Evaluation of bone fusion was performed at the intervertebral disc located at the bottom of the fixed range. The degree of bone fusion was calculated as a score from 2 to 6 points, with 2 defined as complete fusion. Bone fusion rate was also compared at 6 months postoperatively based on BC status of the grafted bone on CT immediately after surgery. Results Mean bone fusion score at 6 months postoperatively was 3.9 points in the WT group and 4.2 points in the BP group. The bone fusion rate at 6 months postoperatively tended to be higher in the WT group (46.8% vs. 32.7% in the BP group). The 6-month postoperative fusion rate of immediately postoperative of BC+ patients was significantly higher than that of BC- patients (47.4% vs. 9.5%). Conclusion In M-LIF, there were no significant differences in bone fusion score between WT- and BP-treated patients. In contrast, BC status immediately postoperatively had a major impact on 6-month bone fusion. Level of evidence 1.

Study design Case report. Objective Describe the clinical and radiological outcomes of a patient with a piezo-type mechanosensitive ion channel component 2 (PIEZO2)-deficient arthrogryposis receiving surgery for severe kyphoscoliosis. Summary of background data Spinal deformity is a characteristic feature of arthrogryposis due to PIEZO2 gene deficiency, for which surgical correction is indicated when the deformity is progressive to avoid neurological deficits and respiratory impairment. However, there exist few reports on the surgical treatment of spinal deformity in PIEZO2-deficient arthrogryposis, and no therapeutic standards have been established. Methods We retrospectively reviewed a case of proximal junctional kyphosis after posterior spinal fusion for severe kyphoscoliosis in PIEZO2-deficient arthrogryposis. Results The patient was a 13-year-old girl with PIEZO2-deficient arthrogryposis who underwent posterior spinal fusion with an all-pedicle screw construct from T2 to L2 for a preoperative main thoracic curve Cobb angle of 78° and thoracic kyphotic angle of 83°. Postoperative Cobb angle of the main thoracic curve and thoracic kyphotic angle were improved at 11° and 34°, respectively. Although revision surgery was required for neurological deficits from proximal junctional kyphosis, she could walk with a crutch and improvements in clinical questionnaire scores were noted at 2 years and 3 months after surgery. Conclusion Based on the present case, posterior spinal fusion represents a good treatment option for severe spinal deformity in PIEZO2-deficient arthrogryposis. Careful consideration of fusion level is needed to prevent proximal junctional kyphosis. Level of evidence 5.

STUDY DESIGN An observational cohort study. OBJECTIVE The aim of this study was to compare the rate of pedicle perforation while inserting screws (PS) using O-arm navigation during surgery for scoliosis with that reported previously and to determine the risk factors specific to O-arm navigation. SUMMARY OF BACKGROUND DATA O-arm navigation provides intraoperative three-dimensional fluoroscopic imaging with an image quality similar to that of computed tomography. Surgeons have started using O-arm navigation in treatment of adolescent idiopathic sclerosis (AIS). However, there are few reports of the perforation rate when using O-arm navigation to insert pedicle screws for AIS. To our knowledge, no information has been published regarding risk factors for pedicle perforation by PS when using O-arm navigation during surgery for AIS. METHODS We retrospectively reviewed the cases of 23 consecutive patients with AIS (all female; mean age 15.4 years, range 12-19 years) who had all undergone PS fixation under O-arm navigation. RESULTS There were 11 major pedicle perforations (Grade 2 or 3) by the 404 screws (2.7%). For both Grade 1 to 3 and Grade 2 or 3 perforations, the pedicle perforation rate by the ninth or subsequent screws was significantly higher than that for the other two groups (screws 1-4, 5-8) (P

Study design A retrospective chart review. Objective The aim of this study was to investigate the incidence and characteristics of screw loosening in surgically treated adolescent idiopathic scoliosis (AIS) patients. Summary of background data Pedicle screws are widely used in posterior spinal fusion for AIS, although postoperative loosening can occur. However, few reports exist on screw loosening after pedicle screw fixation in young scoliosis patients and the etiology of loosening is not well known. Methods One hundred twenty AIS patients (9 males, 111 females; mean age: 15.0 years) who had received pedicle screw fixation were retrospectively reviewed. All patients underwent routine computed tomography (CT) reconstruction scans at 6 months postoperatively to assess screw position, bony fusion, and the presence of screw loosening. The perforation status of each pedicle screw was assigned a grade of 0 to 3 using Rao classification. Results Forty-three of 1624 (2.6%) screws showed evidence of loosening on CT. Screw loosening rates according to vertebral insertion level were upper instrumented vertebra (UIV): 9.6%; lower instrumented vertebra (LIV): 5.4%; one vertebra below the UIV: 1.8%; one vertebra above the LIV: 0.5%; two vertebrae below the UIV: 1.2%; and three vertebrae below the UIV: 0.9%. Screw loosening rates based on screw perforation grade were Grade 0: 1.4%; Grade 1: 3.1%; Grade 2: 15.5%; and Grade 3: 15.2%. Multivariate analysis revealed a distance from the UIV or LIV of one vertebra as well as the presence of major perforation to be independent factors affecting screw loosening. The odds ratios (ORs) of UIV/LIV insertion and major perforation were 73.4 and 17.2, respectively. When major perforations occurred in the UIV or LIV, the OR for loosening approached 1262. Conclusion Pedicle screw loosening after posterior spinal fusion in AIS patients tend to occur in the UIV or LIV. Major screw perforation is also significantly associated with screw loosening. The risk of loosening becomes compounded when major perforations are present in the UIV or LIV. Level of evidence 4.

Case report.We report here on an 18-month-old boy with brachytelephalangic chondrodysplasia punctata (BCDP), whose atlantoaxial instability was successfully managed with occipitocervical instrumented fusion (OCF) using screw and rod instrumentations.Recently, there have been a number of reports on BCDP with early onset of cervical myelopathy. Surgical OCF is a vital intervention to salvage affected individuals from the life-threatening morbidity. Despite recent advancement of instrumentation techniques, however, rigid OCF is technically demanding in very young children with small and fragile osseous elements. To our best knowledge, this is the first report on application of the instrumentation technique to a toddler patient with BCDP.A 16-month-old boy with BCDP presented with tetraplegia and swallow obstacle. Hypoplasia of the odontoid process and atlantoaxial instability were present in lateral radiographs. T2-weighted magnetic resonance (MR) images revealed a high signal region in the spinal cord at the C1-2 and C7-T1 levels. Cervical computed tomography (CT) showed that the pedicles and lateral masses in the cervical spine were small and immature, but the laminae were comparatively thick.One week before surgery, the patient was fitted with a Halo-body jacket. We performed plate-rod placement with occipital cortical screws and C2/C3 interlaminar screws, and added an autogenous bone graft using the right 8 and 9 ribs. Rigid fixation of the occipito-cervical spine was completed successfully without major complications. Postoperative halo-body jacket immobilization was continued for 3 months, after which Aspen collar was fitted. CT confirmed occipitocervical bone fusion at 6 months after surgery. Mild clinical improvements in motor power of the affected muscles and swallowing were witnessed at 1 year postoperatively.Rigid fixation using screw, rod, and occipital plate instrumentation was successful in an 18-month-old toddler with BCDP and atlantoaxial instability. Bone fusion was achieved at postoperative 6 months.5.

Study design Retrospective analysis. Objective To test the hypothesis that preoperative spinal cord damage affects postoperative segmental motor paralysis (SMP). Summary of background data SMP is an enigmatic complication after cervical decompression surgery. The cause of this complication remains controversial. We particularly focused on preoperative T2-weighted high signal change (T2HSC) on magnetic resonance imaging in the spinal cord, and assessed the influence of preoperative T2HSC on SMP after cervical decompression surgery. Methods A retrospective review of 181 consecutive patients (130 males and 51 females) who underwent cervical decompression surgery was conducted. SMP was defined as development of postoperative motor palsy of the upper extremities by at least 1 grade in manual muscle testing without impairment of the lower extremities. The relationship between the locations of T2HSC in preoperative magnetic resonance imaging and SMP and Japanese Orthopedic Association score was investigated. Results Preoperative T2HSC was detected in 78% (142/181) of the patients. SMP occurred in 9% (17/181) of the patients. Preoperative T2HSC was not a significant risk factor for the occurrence of SMP (P = 0.682). However, T2HSC significantly influenced the severity of SMP: the number of paralyzed segments increased with an incidence rate ratio of 2.2 (P = 0.026), the manual muscle score deteriorated with an odds ratio of 8.4 (P = 0.032), and the recovery period was extended with a hazard ratio of 4.0 (P = 0.035). In patients with preoperative T2HSC, Japanese Orthopaedic Association scores remained lower than those in patients without T2HSC throughout the entire period including pre- and postoperative periods (P Conclusion Preoperative T2HSC was associated with worse severity of SMP in patients who underwent cervical decompression surgery, suggesting that preoperative spinal cord damage is one of the pathomechanisms of SMP after cervical decompression surgery. Level of evidence 3.

Retrospective observational study OBJECTIVE.: To clarify the efficacy of recombinant human erythropoietin-beta (EPO-beta) injections during autologous blood donation (ABD) before spinal deformity surgery in children and teenagers.ABD is preferred for spinal deformity surgery. A few studies have assessed the usefulness of preoperative ABD with EPO-beta in anemic patients.Fifty-six spinal deformity surgery patients (41 females, 15 males; median age: 15 yrs; range, 5-19 yrs) underwent preoperative ABD. ABD was performed weekly according to the patient's body weight with a subcutaneous EPO-beta injection (24,000 U). The collected blood volumes were compared among the low hemoglobin (low-Hb) (13 g/dL), mid-Hb (13-13.9 g/dL), and high-Hb (≥14 g/dL) groups using the Kruskal-Wallis test. The effects of EPO-beta injection on the Hb levels were estimated using a linear mixed model.The patients underwent a median of four ABD collections (range, two to six). The median collected volume per ABD was 200 mL (range, 40-400 mL). The median total blood collection was 700 mL (range, 160-1,350 mL); the corresponding values were 700 mL, 700 mL, and 800 mL in the low-Hb, mid-Hb, and high-Hb groups, respectively (P = 0.964). The median blood loss was 500 mL (range, 10-2,940 mL); 53 out of 55 patients (96%) did not require unplanned allogeneic transfusion, including 11 out of 12 (92%) cases with blood loss1,000 mL. The additional recovery of Hb levels with one EPO-beta injection was 0.29 ± 0.14 g/dL (P = 0.039) after adjusting for confounding factors.ABD with an EPO-beta injection is useful for avoiding allogeneic transfusion during spinal deformity surgery in children and teenagers, and patients in the low-Hb group achieved ABD volumes equivalent to those in the high-Hb group. Thus, an additional recovery of Hb levels of 0.29 g/dL per injection can be expected after 1 week.4.