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Study Design: Retrospective cohort study with interrupted time series analysis., Objective: To examine the clinical effectiveness of gelatin-thrombin matrix sealant (GTMS) on blood loss reduction after adolescent idiopathic scoliosis (AIS) surgery., Summary of Background Data: The real-world effectiveness of GTMS on blood loss reduction in AIS surgery has not been determined., Patients and Methods: The medical records of patients receiving AIS surgery were retrospectively collected during a period before GTMS approval at our institution (January 22, 2010-January 21, 2015) as well as during a postintroduction period (January 22, 2015-January 22, 2020). The primary outcomes were intraoperative blood loss, drain output over 24 hours, and total blood loss (intraoperative blood loss + drain output over 24 h). Interrupted time series analysis using a segmented linear regression model was used to estimate the effect of GTMS on blood loss reduction., Results: A total of 179 AIS patients [mean age (range): 15.4 (11-30) yr; 159 females and 20 males; 63 preintroduction patients and 116 postintroduction patients] were included. After its introduction, GTMS was used in 40% of cases. Interrupted time series analysis revealed changes of -340 mL (95% CI: -649 to -31, P = 0.03) for intraoperative blood loss, -35 mL (95% CI: -124 to 55, P = 0.44) for drain output over 24 hours, and -375 mL (95% CI: -698 to -51, P = 0.02) for total blood loss., Conclusions: The availability of GTMS was significantly associated with reduced intraoperative and total blood loss in AIS surgery. GTMS use as needed is recommended to control intraoperative bleeding in the setting of AIS surgery., Level of Evidence: 3., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

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 yr) 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, operation room 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., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective study of a cohort of consecutive patients., Objective: The aim of this study was to clarify the usefulness and value of the difference in thoracic kyphosis (ΔTK) angle in various positions by imaging the patient standing, prone, and supine to evaluate TK flexibility and compensation, and to establish optimal radiography to determine an appropriate thoracic level for upper instrumented vertebra (UIV) because a strategy to select an appropriate level to avoid proximal junctional kyphosis (PJK) remains elusive., Summary of Background Data: Postoperative reciprocal progression of TK is a significant risk factor for PJK. However, how to predict and prevent postoperative reciprocal progression of TK remains unclear. We hypothesized that preoperative evaluation of both TK flexibility and compensation is essential to predict PJK and determine the UIV level., Methods: We included 144 consecutive patients with adult spinal deformity (ASD), ≥2 years' follow-up, and UIV Th9-11 in this retrospective cohort study. TK was measured from images with patients standing, prone, and supine. Supine ΔTK was calculated as standing TK- supine TK. Prone ΔTK was calculated as standing TK - prone TK. Receiver-operating characteristic (ROC) curves were analyzed to determine the thresholds of supine ΔTK and prone ΔTK for PJK occurrence., Results: PJK was observed in 64 of 144 (44%) patients 2 years postoperatively. Prone and supine ΔTKs were significantly larger in patients with PJK. A significant positive correlation between prone ΔTK and supine ΔTK was observed. When data from patients with and without PJK were plotted separately, a significantly higher proportion of patients with PJK had large prone and supine ΔTKs. The cutoff values of prone and supine ΔTKs for PJK risk were determined using ROC curve analysis., Conclusion: Because of their significantly high risk for PJK, in patients with ASD and prone ΔTK >11.5° and supine ΔTK >18.5°, the upper-thoracic spine should be considered for UIV.Level of Evidence: 3., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective observational study of a cohort of consecutive patients., Objective: The aim of this study was to compare surgical invasion, mechanical complications, and clinical and radiological outcomes 2 years after surgery between minimally invasive corpectomy following percutaneous pedicle screw placements (X-core/PPS) and posterior fixation with vertebroplasty (VP) for treating osteoporotic vertebral fractures (OVFs), which failed conservative treatment due to neurological deficits., Summary of Background Data: Numerous studies have proposed surgical procedures to treat OVFs that fail conservative treatment. However, an optimal approach remains controversial because patients often have numerous comorbid medical complications, frequent instrumentation failure, and/or adjacent vertebral fracture (AVF). Recently, a minimally invasive lateral approach has attracted attention as an alternative procedure to the thoracolumbar junction for corpectomy and expandable cage replacement (X-Core Adjustable VBR System). However, its usefulness and validity is largely unknown., Methods: A cohort of 102 consecutive patients with OVF at T11-L1 who underwent surgery were followed up for >2 years after surgery. Ultimately 50 patients were included in the VP group and 45 in the X-core/PPS group. Surgical invasion, radiological examinations, and clinical outcomes between two procedures were compared., Results: Both X-core/PPS and VP procedures were safe and acceptable for neurological improvement and surgical invasion. The correction loss of local kyphotic angle (LKA) and occurrence of AVF were significantly less in the X-core/PPS group. Oswestry Disability Index in the X-core/PPS group at 2 years after surgery showed better recovery than that in the VP group, and no revision surgery was needed in the X-core/PPS group. Postoperative correction loss of LKA increased significantly when intraoperative endplate injury developed., Conclusion: This next-generation minimally invasive anterior and posterior combined surgery was found to be a safe and useful procedure for OVF treatment to reduce correction loss, mechanical complication, and AVF, resulting in less postoperative low back pain.Level of Evidence: 3., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective multicenter study., Objective: This study aimed to investigate the incidence and risk factors of subjacent disc wedging (SDW) in adolescent idiopathic scoliosis (AIS) patients with Lenke type 5 curve., Summary of Background Data: SDW is frequently observed after surgery; however, data about its mechanism and relations with outcome are limited., Methods: Data of 59 patients with AIS with Lenke type 5 curves who underwent posterior spinal fusion to L3 as the lowest instrumented vertebra (LIV) were retrospectively analyzed. The subjacent disc angle (SDA) was defined as the angle between L3 (LIV) and L4. SDW was defined as the absolute value of SDA of 10° or higher 2 years postoperatively. The incidence of SDW was investigated between nonselective and selective thoracolumbar/lumbar (TL/L) fusion group. In the selective group, patients with and without SDW were compared., Results: Among 59 patients, 11 had nonselective and 48 had selective fusion. No patients in the nonselective group showed SDW versus 13 patients in the selective group (27%) showed SDW. In the selective group, patients with SDW showed significantly greater main thoracic curve, apical vertebral translation of the main thoracic curve, upper instrumented vertebra tilt, LIV tilt, and SDA 2 years postoperatively, whereas no differences were found in the coronal balance or clinical outcome. Multivariate analysis revealed preoperative T curve and SDA as predictors of SDW occurrence. T curve greater than 30° and SDA greater than 0° were calculated as cutoff values based on the receiver operating characteristic curve., Conclusion: SDW is sometimes seen in Lenke type 5 patients with AIS who underwent selective TL/L fusion. SDW seemed to occur as a compensation mechanism for progressing deformity of unfused segments (thoracic curve and residual lumbar curve) to maintain coronal alignment. Preoperative T curve > 30° and SDA > 0° (lower-end vertebra as L4) were determined as risk factors for SDW occurrence.Level of Evidence: 3., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

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 < 0.05)., 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: A multicenter, randomized, open-label, parallel-group trial., Objective: To investigate interbody bone fusion rates in titanium-coated polyetheretherketone (TiPEEK) and polyetheretherketone (PEEK) cages after posterior lumbar interbody fusion (PLIF) surgery., Summary of Background Data: Previous clinical studies have not revealed any significant difference in bone fusion rates between TiPEEK and PEEK cages., Methods: During one-level PLIF surgery, 149 patients (84 men, 65 women, mean age 67 yr) were randomly allocated to use either a TiPEEK cage (n = 69) or PEEK cage (n = 80). Blinded radiographic evaluations were performed using computed tomography and assessed by modified intention-to-treat analysis in 149 cases and per-protocol analysis in 143 cases who were followed for 12 months. Clinical outcomes were assessed using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire and the Oswestry Disability Index., Results: The interbody union rate at 12 months after surgery was 45% owing to a very strict definition of bone fusion. The rates of bone fusion were significantly higher at 4 and 6 months after surgery in the TiPEEK group than in the PEEK group in the unadjusted modified intention-to-treat analysis and were significantly higher at 6 months in the unadjusted per-protocol analysis. Binary logistic regression analysis adjusted for sex, age, body mass index, bone mineral density, and surgical level showed that using a TiPEEK cage (odds ratio, 2.27; 95% confidence interval: 1.09-4.74; P = 0.03) was independently associated with bone fusion at 6 months after surgery. Japanese Orthopaedic Association Back Pain Evaluation Questionnaire and Oswestry Disability Index results improved postoperatively in both groups., Conclusion: Using the TiPEEK cage for PLIF enabled the maintenance of better bone fusion to the endplate than using the PEEK cage at 6 months after the surgery. Our findings suggest the possibility of an earlier return to rigorous work or sports by the use of TiPEEK cage., Level of Evidence: 1.

Study Design: Retrospective observational study., Objective: The study objectives were to: (1) determine radiographically which spinal malalignment parameters predominantly influence the risk of gastroesophageal reflux disease (GERD); (2) evaluate the outcome of GERD 2 years after surgery for adult spinal deformity (ASD); and (3) clarify key factors that influence the improvement of postoperative GERD in ASD., Summary of Background Data: Spinal deformity is reported to be involved in the pathology of GERD. Our previous study found that approximately 50% of patients treated surgically for ASD had GERD symptoms. However, the postoperative progress of GERD and the key factors that influence the improvement of postoperative GERD are largely unknown., Methods: Ninety-two patients with ASD treated with thoracolumbar corrective surgery and followed up for a minimum of 2 years were enrolled. All patients were asked to complete the Frequency Scale for Symptoms of GERD (FSSG) questionnaire preoperatively and at 1 and 2 years after surgery. GERD was diagnosed by FSSG score more than 8 points. Before, and at 1 and 2 years after surgery, full-length lateral radiographs were taken and radiographic parameters were obtained., Results: Patients were classified into two groups based on GERD symptoms, with 47 (51.1%) in the GERD+ group. Among parameters assessed, only thoracolumbar kyphosis (TLK) was significantly greater in the GERD+ group than in the GERD- group. The FSSG score improved significantly 1 year after surgery, but no significant difference was found between groups at 2 years. A significant correction loss of TLK was observed 2 years after surgery. There was a significant highly positive correlation between the FSSG score and TLK at 2 years after surgery., Conclusion: GERD improved with correction of the spinal deformity but significant correction loss of the TLK even within the fusion presumably due to subsidence or proximal junctional kyphosis resulted in a cessation of that improvement over time., 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: Retrospective observational study of a cohort of consecutive patients., Objective: To determine 1) the correlation between clinical and radiographic outcomes and Global Alignment and Proportion (GAP) score, and 2) which preoperative parameters predominantly influence the risk for poor GAP scores., Summary of Background Data: Although numerous investigators have indicated their criteria for sagittal correction, it is still not unusual to observe poor outcome or complications even after ideal correction. The recently developed GAP score indicates spinopelvic alignment and setting surgical goals according to the score might decrease the prevalence of mechanical complications. However, there is no clear evidence of correlation between the GAP score and clinical outcomes, or which patient factors are preoperative predictors of poor postoperative GAP score., Methods: We included 128 consecutive patients treated with spinal correction surgery who had a minimum 2-year follow-up. The correlations between clinical outcomes, increased proximal junctional angle, and GAP score were determined. Univariate and multivariate logistic regression analyses were conducted to clarify potential preoperative risk factors for poor GAP score., Results: Based on total GAP score, 32 (25%) patients were grouped into proportioned, 50 (39.1%) into moderately disproportioned, and 44 (34.3%) into severely disproportioned spinopelvic alignment. Our present study showed a significantly positive correlation between Oswestry Disability Index, increased proximal junctional angle 2 years after surgery, and total GAP score. Uni and multivariate regression analysis showed a large global tilt was a risk factor for a poor GAP score and that the risk for a poor GAP score increased with ageing., Conclusions: Because GAP score correlated with Oswestry Disability Index and increased proximal junctional angle 2 years after surgery, GAP score might define targets for sagittal spinopelvic alignment for favorable outcomes of corrective spinal surgery. A large preoperative global tilt is a potential predictor of poor postoperative GAP score., Level of Evidence: 3.

Study Design: A multicenter case-control study., Objective: The aim of this study was to investigate the independent predictors of osseous union after posterior lumbar interbody fusion (PLIF)., Summary of Background Data: PLIF is usually performed to treat lumbar degenerative diseases in elderly patients. Some patients exhibit intervertebral pseudoarthrosis., Methods: We analyzed 66 elderly patients with osteoporosis who underwent PLIF from 2011 to 2014 (all women, mean age 71 years, follow-up period ≥6 months). Patients were randomly allocated to receive either treatment with weekly teriparatide, starting at 1 week postoperatively, or no teriparatide. Preoperative lumbar spine radiographs were obtained, and the amount of anterior slippage was measured. Osseous union was assessed by computed tomography at 6 months postoperatively., Results: Thirty-three patients (50%) showed complete osseous union, while 33 did not. Teriparatide was administered in 20 (61%) patients of the union group and in 9 (27%) patients of the nonunion group (P < 0.01). The preoperative anterior slippage of the cranial vertebra next to fusion segment < 2 mm was observed in 16 (49%) and 4 (12%) patients in the union and nonunion groups, respectively (P < 0.01). Multivariate regression analysis showed that teriparatide administration (odds ratio, 4.75; 95% confidence interval: 1.51-14.90; P < 0.01) and preoperative anterior slippage of the cranial vertebra next to fusion segment < 2 mm (odds ratio, 5.90; 95% confidence interval: 1.53-22.70; P < 0.01) were independently associated with osseous union within 6 months after PLIF. At 6 months postoperatively, the mean femoral neck bone mineral density significantly increased by 1.1% in the union group and decreased by 1.3% in the nonunion group (P < 0.05)., Conclusion: Weekly teriparatide administration and preoperative anterior slippage of the cranial vertebra next to fusion segment < 2 mm were independent predictors of osseous union within 6 months after PLIF. Our findings suggest that biological and mechanical factors may influence the improvement of spinal fusion., Level of Evidence: 4.

Study Design: Retrospective observational cohort study., Objective: To determine change in pelvic incidence (PI) and loss of correction after long fusion with iliac screws, the effect of iliac screw loosening, and global alignment according to postoperative PI., Summary of Background Data: Posterior long fixation and fusion of the thoracic to the ilium is one of the most common surgical treatments for adult spinal deformity (ASD). Long fusion to the sacrum with iliac screws decreases the PI by 3.9° after surgery. PI decreases once by long fusion with iliac screws. However, if the iliac screw loosens, PI may cause correction loss and return to the preoperative PI., Methods: We retrospectively reviewed the cases of 69 consecutive patients with ASD. Their mean age (SD) was 70.5 (7.3) years, 12% were male. PI was evaluated preoperatively, early- and 1-year postoperatively. We compared change in PI with and without loosening of iliac screws, spinopelvic parameters according to 1-year-postoperative PI., Results: PI decreased significantly from 51.8° (9.3°) to 48.1° (9.5°) early postoperatively (P < 0.01). PI increased significantly from 48.1° (9.5°) to 49.6° (9.7°) within a year postoperatively (P < 0.01). Significant loss of PI correction (2.3°, P < 0.01) occurred within a year after surgery in patients with iliac screw loosening and was significantly different from the PI loss in those without screw loosening (53.9°, 48.2°, P = 0.03). Pelvic tilt, sacral slope, C7 sagittal vertical axis, global tilt, and T1 pelvic angle were significantly smaller in the group with PI <50° postoperatively at 1 year compared with the group with PI >50°., Conclusion: Although PI decreases after long fusion surgery with iliac screws, significant correction loss appears within a year. Loosening of iliac screws may exacerbate this loss. Patients with PI <50° postoperatively were able to maintain better global alignment., Level of Evidence: 3.

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 < 0.01). Grade 1 to 3, Grades 2 or 3, and Grade 3 perforation rates after a previous perforation were significantly higher than those in patients without a previous perforation (P < 0.01). The rate of screw deviation can increase significantly to 12.2% after insertion of 8., Conclusion: The rate of major perforation of pedicles after inserting PS using O-arm navigation during surgery for AIS is relatively low. However, we recommend caution using intraoperative navigation after inserting eight pedicle screws because after this, the trajectory deviation rate can increase significantly., Level of Evidence: 3.

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: Case report., Objective: 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., Summary of Background Data: 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., Methods: 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., Results: 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., Conclusion: 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., Level of Evidence: 5.