Search

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.

This is a retrospective single-center and single-surgeon study.We investigated the correlation between lower instrumented vertebra (LIV) and spinal mobility 2 years after posterior spinal fusion with pedicle screws for adolescent idiopathic scoliosis (AIS) for optimal LIV selection.Spinal motion can become limited in scoliosis patients who undergo posterior spinal fusion. However, few reports exist on spinal mobility after posterior spinal fusion for AIS and the relationship between the LIV and mobility is unknown. We hypothesize that mobility limitation increases as the LIV is moved inferiorly.Of 72 consecutive patients who received posterior spinal fusion using pedicle screws for AIS between October 2009 and August 2015, 66 patients (5 male and 61 female, mean age: 14.9 y) were enrolled.In total, 66 patients were retrospectively reviewed after stratification according to LIV level. Follow-up rate was 91.7%. Patients were examined for the fingertip-to-floor distance (FFD) before and 2 years after surgery. FFD was measured from the tips of the middle fingers to the floor with the barefoot subject bent maximally forward and the feet together and knees straight. Clinical outcome was assessed using Scoliosis Research Society-22 patient questionnaire (SRS-22r) scores and a visual analog scale for low back pain before and at 2 years postoperatively.The median number of fused vertebrae was 9 (range: 4-15). The LIV was T11-12 in 15 patients, L1 in 11 patients, L2 in 10 patients, and L3 in 30 patients. The median decrease in FFD according to LIV at 2 years after surgery was T11-12: 0 cm, L1: 0 cm, L2: 5.5 cm, and L3: 10 cm. Thus, limited FFD became significantly more severe as the LIV was moved downwards (P0.01). There were no significant correlations between limited FFD and SRS-22r or pain visual analog scale scores at 2 years postoperatively.FFD became significantly more restricted as the LIV was moved inferiorly but clinical results appeared unaffected by limited FFD.

STUDY DESIGN Retrospective, single-center, single-surgeon study. OBJECTIVE This study investigated screw perforation rate according to surface registration accuracy in pedicle screw fixation using a CT-based navigation system for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA Posterior spinal fusion for scoliosis correction using pedicle screws is widely adopted but carries a risk of serious neurovascular or visceral structure events. To attempt to avoid these complications, we have been using a computed tomography (CT)-based navigation system during screw insertion, although insufficient surface registration accuracy may be a reason for some screw perforations. METHODS We evaluated 116 AIS patients (9 male and 107 females; mean±standard deviation age: 15.2±2.3 y) who had received pedicle screw fixation guided by a CT-based navigation system between August 2007 and December 2017. Screw perforation rate was evaluated in relation to surface registration accuracy and cut-off values were determined by receiver operating characteristic (ROC) curves. RESULTS A total of 1553 pedicle screws were inserted into T2-L4 vertebrae using CT-based navigation system. The respective overall perforation rates for grade 2 or 3 and grade 3 perforations by surface registration accuracy were 0.2 mm: 0% and 0%; 0.3 mm: 3.5% and 0%; 0.4 mm: 3.5% and 0.8%; 0.5 mm: 8.0% and 3.5%; 0.6 mm: 6.7% and 2.7%; 0.7 mm: 8.9% and 3.8%; 0.8 mm: 9.3% and 6.7%; and 0.9 mm: 9.3% and 4.7%. ROC curve analysis revealed a cut-off surface registration accuracy of 0.5 mm. The major screw perforation rate for a surface registration accuracy of ≥0.5 mm was significantly higher than that for

STUDY DESIGN This is a retrospective single-center and single-surgeon study. OBJECTIVE The present study examined for preoperative parameters having the highest correlation with compensatory thoracolumbar/lumbar (TL/L) curve correction 2 years after surgery in adolescent idiopathic scoliosis (AIS) patients with Lenke type 1 curves. SUMMARY OF BACKGROUND Several parameters have been considered to evaluate the flexibility of compensatory TL/L curve in AIS patients with Lenke type 1 curves. However, the imaging position with the strongest correlation with postoperative spontaneous TL/L curve correction is unknown. DATA In total, 37 patients with AIS Lenke type 1 curves who had undergone skip pedicle screw fixation were followed for a 2-year period were enrolled. MATERIALS AND METHODS TL/L Cobb angles measured at the standing posteroanterior view, supine position, supine position with maximum bending, supine position with traction, prone position, and prone-push position were determined before surgery. Using TL/L Cobb angles determined 2 years postoperatively, correlations between preoperative and postoperative Cobb angles were calculated for each position using the Spearman rank-correlation coefficient, linear regression analysis, and paired t tests. RESULTS Mean preoperative mean±SD TL/L Cobb angle was significantly improved from 31±9 to 13±8 degrees at the study end point. In analyses of correlations between postoperative TL/L Cobb angle and preoperative parameters, the supine position with traction was most strongly associated with TL/L curve correction rate at 2 years after surgery (r=0.72; P

BACKGROUND The most severe complication after surgery for adolescent idiopathic scoliosis is spinal cord injury. There is a relationship between corrective surgery and subsequent elongation of the spinal canal. We sought to investigate which factors are involved in this phenomenon. METHODS Seventy-seven patients with adolescent idiopathic scoliosis (49 with Lenke type 1 and 28 with type 2) who underwent spinal correction surgery were included. The mean patient age at surgery was 14.2 years (range, 11 to 20 years). The spines of all patients were fused within the range of T2 to L2, and computed tomography (CT) data were retrospectively collected. We measured the preoperative and postoperative lengths of the spinal canal from T2 to L2 using 3-dimensional (3D) CT-based imaging software. We also examined the association between the change in T2-L2 spinal canal length and the radiographic parameters. RESULTS The length of the spinal canal from T2 to L2 was increased by a mean of 8.5 mm in the patients with Lenke type 1, 12.7 mm in those with type 2, and 10.1 mm overall. Elongation was positively associated with the preoperative main thoracic Cobb angle in both the type-1 group (R = 0.43, p < 0.005) and the type-2 group (R = 0.77, p < 0.000001). The greatest elongation was observed in the periapical vertebral levels of the main thoracic curves. CONCLUSIONS Corrective surgery for adolescent idiopathic scoliosis elongated the spinal canal. The preoperative proximal, main thoracic, and thoracolumbar/lumbar Cobb angles are moderate predictors of postoperative spinal canal length after scoliosis surgery. CLINICAL RELEVANCE It is important to understand how much the spinal canal is elongated after surgery to lessen the risk of intraoperative and postoperative neurological complications.

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.

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.

Rationale: Fusionless techniques for early-onset scoliosis (EOS) have evolved to allow near-normal growth while maintaining the correction achieved during the initial surgery. However, such procedures require repeated surgeries and have increased complication rates. We have developed a 2-stage fusion technique using pedicle screws for EOS to reduce patient burden and complication risk. This series describes the clinical and radiological features of 2 patients with EOS who received 2-stage posterior spinal fusion. This surgical method for EOS represents the first of its kind. Patient concerns: Case 1 was a 10-year-old girl who was diagnosed as having scoliosis with Prader Willi syndrome at the age of 2 years. Her preoperative major curve Cobb angle was 100 degrees at age 10 years. Case 2 was an 11-year-old boy who was found to have scoliosis with 22q11.2 deletion syndrome at the age of 4 years. His preoperative major curve Cobb angle was 77 degrees at age 11 years. Diagnosis: Whole-spine radiographs were performed to diagnose scoliosis. Interventions: Both patients received 2-stage posterior spinal fusion. Outcomes: Postoperative Cobb angle of the major curve improved to 46 and 48 degrees, respectively. Thoracic height respectively improved from 160 and 148 mm before surgery to 206 and 211 mm at final follow-up. Surgical outcome as evaluated by Scoliosis Research Society-22 patient questionnaires revealed acceptable results without any severe complications. Lessons: Based on the present case report, 2-stage posterior spinal fusion for EOS achieves good radiological and clinical outcomes without severe complications.

Interest is mounting regarding diffuse idiopathic skeletal hyperostosis (DISH) as the rate in the elderly increases. Although some studies have demonstrated an effect of DISH on sagittal spinal alignment, the pathogenetic mechanism remains unknown. Random sampling from the basic resident registry of a rural town for subject selection was used to investigate the impact of DISH on sagittal spinal alignment. Methods Registered citizens who were 50 to 89 years of age were targeted for this survey. We divided the study population into 8 groups based on sex (male and female) and age (50 to 59, 60 to 69, 70 to 79, and 80 to 89 years) after random sampling from the resident registry of the town of Obuse in 2014. A total of 411 participants (202 male and 209 female) were enrolled and underwent a whole-spine lateral radiographic examination. We investigated the spinal level of DISH occurrence, measured sagittal spinal alignment parameters, and analyzed the effects of clinical factors on DISH using multivariate analysis. Results A total of 66 participants (16.1%) were identified as having DISH in our population cohort. With regard to DISH involving the thoracic spine, sagittal vertical axis, cervical sagittal vertical axis, T1 slope, thoracic kyphosis, aging, and male sex were significantly associated with DISH in the univariate analysis. Aging and male sex were also independent factors according to multivariate analysis; the odds ratio (OR) was 1.70 for aging per decade and 3.75 for male sex. Sagittal vertical axis, lumbar lordosis, sacral slope, pelvic tilt, aging, and male sex had significant associations with DISH involving the lumbar spine in univariate analysis, with decreased lumbar lordosis (OR, 1.82), aging per decade (OR, 4.35), and male sex (OR, 10.7) as independent factors in multivariate analysis. Conclusions In this study examining the impact of DISH on sagittal spinal alignment in a general population, decreased lumbar lordosis was significantly associated with DISH involving the lumbar spine in the healthy community-dwelling elderly population, and no sagittal spine parameters were significantly related to DISH affecting the thoracic spine. Clinical relevance When there is decreased lumbar lordosis in elderly people, we should check for the existence of DISH.