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To evaluate the surgical results of patients with cervical spondylotic myelopathy (CSM) with inconsistency between deep tendon reflex findings and cervical magnetic resonance imaging (MRI) findings and to analyze the differences between patients with good and poor surgical outcomes.We evaluated 50 subjects with CSM (30 males, 20 females; mean age: 70.4 years) who underwent posterior surgery and were followed for at least 1 year postoperatively. Matched CSM was defined as a consistent preoperative neurological pattern determined by deep tendon reflex and cervical MRI T2-weighted high-signal intramedullary area or stenosis in the most cranial compression levels. A lack of consistency was classified as unmatched CSM. Recovery rate (RR) according to Japanese Orthopaedic Association (JOA) scoring preoperatively and at 1 year postoperatively were compared between the groups.The matched and unmatched CSM group included 27 subjects (13 males, 14 females; mean age: 68.2 years) and 23 subjects (17 males, 6 females; mean age: 72.8 years), respectively. RR was significantly higher in the matched CSM group (56.1 ± 3.7 % vs 36.8 ± 2.7 %; p = 0.002). Unmatched CSM was significantly associated with a lower RR independently of sex, patient age, surgical procedure, preoperative JOA score, diagnosis levels, and complication of diabetes.Postoperative JOA score RR was significantly diminished among unmatched CSM patients comprising of 46% of cases. Some patients with unmatched CSM had multiple levels of spinal canal stenosis, foraminal stenosis, and peripheral neuropathy, suggesting that surgical results were poorer than those of matched CSM.

Posterior spinal fusion with pedicle screws is commonly used for the treatment of adolescent idiopathic scoliosis (AIS). To reduce radiation exposure, methods other than computed tomography (CT) are desirable for preoperative determination of pedicle diameter.Investigate the differences between magnetic resonance imaging (MRI) and CT measurements of pedicle diameter.Cross-sectional research.Twenty-one AIS Lenke type 1 patients (19 female and 2 males, mean age at surgery: 15.4 years) who underwent posterior spinal fusion between April 2009 and October 2019.Gap between CT and MRI pedicle diameters.The inner and outer diameters of the right and left pedicles from T1 to L3 were measured separately by two spine surgeons for statistical comparisons.The respective minimum and maximum CT-MRI values were -3.7 mm and 4.7 mm for inner diameter and -4.6 mm and 5.3 mm for outer diameter. Regarding inter-examiner error, the probability of a 2 mm difference in measurement was less than 5% for both modalities. The probability of a 1 mm difference was also less than 5%, and that of a 3 mm or more difference was 2.1% for the inner diameter and 2.9% for the outer diameter. Whereas low body weight was significantly associated with measurement differences, pedicle laterality was not.MRI does not have the reliability to measure pedicle size in AIS patients at present. However, with advancements in image processing technology, the accuracy of pedicle size measurement by MRI may soon improve.

Introduction: In this study, we present “microscopic mini-open foraminotomy (MicroMOF)” as a new, less invasive method for posterior cervical foraminotomy. Technical Note: Using surgical microscope guidance, the spinous process is hemi-split, and the posterior muscle is detached from the laminar subperiosteal surface. Bony resection is then performed obliquely from medial posterior to lateral anterior under lateral-tilted surgical field exposure. MicroMOF has been performed successfully for cervical radiculopathy and cervical spondylotic amyotrophy, which achieved postoperative symptom improvement with few complications. Conclusions: The novel MicroMOF foraminotomy technique has been found to protect the nerve root and vertebral artery and help preserve muscle and cervical facet joint bone.

Background Postoperative intracranial complications are rare in spine surgery not including cranial procedures. We describe an uncommon case of pseudohypoxic brain swelling (PHBS) and secondary hydrocephalus after transforaminal lumbar interbody fusion (TLIF) presenting as impaired consciousness and repeated seizures. Case presentation A 65-year-old man underwent L4-5 TLIF for lumbar spondylolisthesis and began experiencing generalized seizures immediately postoperatively. Computed tomography (CT) revealed diffuse cerebral edema-like hypoxic ischemic encephalopathy. He was transported to our hospital, at which time epidural drainage was halted and anti-edema therapy was commenced. His impaired consciousness improved. However, he suffered secondary hydrocephalus due to continuous bleeding from a dural defect and spinal epidural fluid collection 3 months later. Following the completion of dural repair and insertion of a ventriculoperitoneal shunt, his neurologic symptoms and neuroimaging findings improved significantly. Conclusions PHBS can be considered in patients with unexpected neurological deterioration following lumbar spine surgery even with the absence of documented durotomy. This might be due to postoperative intracranial hypotension-associated venous congestion, and to be distinguished from the more common postoperative cerebral ischemic events-caused by arterial or venous occlusions-or anesthetics complications.

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.

Background Musculocontractural Ehlers-Danlos syndrome caused by pathogenic variants in CHST14 (mcEDS-CHST14) is a recently delineated connective tissue disorder characterized by multisystem congenital malformations and progressive connective tissue fragility-related manifestations. With only 2 cases of mcEDS-CHST14 containing precise information on surgical spinal correction being reported to date, there remains no consensus on treatment standards. This study describes the detailed clinical and radiologic outcomes of the third known patient with mcEDS-CHST14 who successfully underwent surgery for severe kyphoscoliosis. Case Description The patient was a 19-year-old girl with mcEDS-CHST14 who suffered from low back pain and decreased daily activities caused by progressive kyphoscoliosis. She underwent posterior spinal fusion with an all-pedicle screw construct from T4 to L4 for a preoperative main curve Cobb angle of 69 degrees and kyphotic angle of 27 degrees. Postoperative Cobb angle of the main curve and kyphotic angle were 26 and 6 degrees, respectively. Although sufficient correction was achieved without disseminated intravascular coagulation or other serious sequelae, a large amount of blood (2600 g) was lost due to tissue fragility. Her low back pain was decreased at 1 year after surgery. Conclusions On the basis of the present and 2 earlier reported cases, posterior spinal fusion may be a reasonable surgical option for severe progressive spinal deformities in patients with mcEDS-CHST14. However, careful attention is needed for possible massive blood loss from tissue fragility.

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.

BACKGROUND: Amyloidosis is a rare group of diseases in which fibrillar amyloid proteins are deposited in systemic organs to result in functional disorder. However, amyloidosis affecting the cervical spine is very rare. We herein describe a case of systemic amyloidosis including a combination of cervical myelopathy with amyloid deposition and cardiac dysfunction due to cardiac amyloidosis. CASE PRESENTATION: An 86-year-old man with cervical myelopathy accompanied with cardiac dysfunction due to cardiac amyloidosis underwent posterior cervical laminectomy from C3 to C4. We were able to identify the patient’s cardiac amyloidosis and significant cardiac dysfunction before surgery and manage his perioperative treatment successfully. Preoperative cervical computed tomography (CT) showed multiple fine calcifications below the lamina, which were later confirmed by pathological analysis as amyloid deposition. CONCLUSIONS: This is a relatively rare report of systemic amyloidosis including a combination of cervical myelopathy with amyloid deposition and cardiac dysfunction from cardiac amyloidosis. CT findings of multiple fine calcifications suggest the possibility of amyloidosis and may warrant further examination of cardiac function.

Background Patients with congenital heart disease (CHD) are associated with an increased incidence of scoliosis, often with severe progression. We report a case of hemoptysis caused by rapid scoliosis progression subsequent to surgery for CHD that was successfully managed by surgical curve correction following coil embolization. Case presentation A 14-year-old girl with scoliosis had undergone open heart surgery for CHD at the age of 1 year. She was first noted to have scoliosis at 12 years of age, which began to progress rapidly. At age 13, her main thoracic curve Cobb angle was 46°, and hemoptysis with high pulmonary vein pressure due to vertebral rotation was detected. Nine months after coil embolization, she received posterior spinal fusion from T5 to L2 for scoliosis correction. Postoperatively, her pulmonary vein diameter was enlarged, with no detectable signs of hemoptysis. Conclusions We encountered a case of hemoptysis caused by advanced scoliosis after cardiac surgery that was successfully treated by correction of the scoliotic curve following coil embolization. Patients with secondary scoliosis after surgery for CHD should be carefully monitored for the possibility of cardiovascular system deterioration.

Objective: Cervical pedicle screw (CPS) fixation is widely used for the treatment of cervical spinal instability from various causes; however, there are few reports on the long-term outcomes of this procedure. The present study evaluated the 10-year results of CPS fixation for cervical instability. Methods: The medical records of 13 consecutive patients who underwent computer-guided CPS fixation for cervical instability were reviewed. The mean observation period was 153 months. Evaluated items included Japanese Orthopaedic Association (JOA) score and C2-7 lordotic angle before surgery and at 5 and 10 years afterwards. Visual analog scale (VAS) scores for neck pain and radiological evidence of adjacent segment degeneration (ASD) at 10 years of follow-up were also assessed. Results: Mean JOA score significantly improved from 9.4 points before surgery to 13.2 points at 5 years after surgery (p

No validated systems exist for selecting the upper instrumented vertebra (UIV) for optimal postoperative shoulder balance in Lenke type 2 adolescent idiopathic scoliosis (AIS). This study evaluated a new method for shoulder balance prediction using the modified Shinshu line (MSL) for UIV selection in AIS Lenke type 2 curves. Fifty-five consecutive AIS patients receiving posterior spinal fusion (PSF) for a Lenke type 2 AIS curve were retrospectively analyzed according to several UIV determination models. Shoulder imbalance was judged as absolute radiographic shoulder height ≥ 10 mm at the 2-year observational endpoint. The MSL was the line between the center of the spinous process of C7 and that of the lowest instrumented vertebra. The vertebral body first touched proximally by the MSL was defined as the MSL vertebra (MSLV) and recommended as the UIV. The group with the UIV matching the MSLV had a significantly lower prevalence of shoulder imbalance of 23% (odds ratio 4.08, 95% CI 1.22–13.7, P = 0.02). Setting the MSLV as the UIV in PSF for AIS Lenke type 2 may reduce the prevalence of postoperative shoulder imbalance.

Study Design: Retrospective cohort study.Purpose: This study aimed to evaluate the relationship between C7 plumb line (C7PL) decompensation and the Scoliosis Research Society (SRS) 22-item patient questionnaire scores, including those related to self-image, preoperatively and 2 years after surgery.Overview of Literature: In the surgical treatment of adolescent idiopathic scoliosis (AIS), inferior trunk balance caused by C7PL decompensation can negatively affect patients’ quality of life. However, there are few reports in the literature that describe or clarify how postoperative trunk imbalance affects each SRS-22 domain, including self-image domain scores.Methods: A total of 120 patients with AIS who underwent posterior spinal fusion from August 2006 to March 2017 at our facility and were followed up for 2 years or more were included. Radiological parameters were measured on whole-spine anteroposterior and lateral radiographs. Revised SRS-22 (SRS-22r) values were also recorded. Coronal trunk imbalance was defined as a deviation of ≥2.0 cm between the C7PL and the central sacral vertical line. Patients with and without coronal trunk imbalance at 2 years after surgery were defined as D (+) (decompensation type) and D (-), respectively. Mean SRS-22r values, including function, pain, self-image, mental health, and subtotal were compared between the D (+) and D (-) groups. Logistic regression analysis was performed to detect the preoperative factors related to D (+) using predictors, including curve type, maximum Cobb angle, and coronal trunk imbalance.Results: At 2 years after surgery, the D (+) group had a significantly lower self-image in the domain of SRS-22r scores compared with the D (-) group. Preoperative coronal trunk imbalance was significantly related to D (+) but not to significant changes in the postoperative SRS-22 score in any of the SRS-22 domains.Conclusions: Postoperative C7PL deviation lowers the self-image in patients with AIS. Patients with preoperative coronal trunk imbalance were significantly more likely to be D (+).

Background Due to the limited number of reports comparing posterior fusion with posterior decompression alone for retro-odontoid pseudotumor, there remains no consensus on treatment preference, especially in older patients. This study compared posterior fusion (with or without additional decompression) with posterior decompression alone for treating spinal cord pressure from non-inflammatory retro-odontoid pseudotumor with atlanto-axial subluxation (AAS). Methods Forty-one patients (27 male and 14 female; mean age, 73.0 ± 11.4 years) who underwent either posterior cervical fusion or decompression alone for the treatment of non-inflammatory retro-odontoid pseudotumor with AAS and were observed for more than 1 year between September 2009 and July 2019 were enrolled. Thirty-two patients (23 male and 9 female; mean age: 71.8 ± 10.9 years) received posterior fusion surgery (fusion group) and 9 patients (4 male and 5 female; mean age: 77.2 ± 12.5 years) underwent decompression alone (non-fusion group). We compared pre- and postoperative Japanese Orthopaedic Association (JOA) scores and preoperative cervical alignment parameters between the groups. Results In the fusion group, the mean preoperative JOA score was significantly improved from 9.0 ± 3.2 points to 11.7 ± 3.2 points at the final follow-up (p = 0.0002). Similarly in the non-fusion group, the mean preoperative and final follow-up JOA scores were 8.2 ± 3.5 points and 11.7 ± 3.8 points, respectively (p = 0.003). The recovery rate at the final follow-up was 22.6% in the fusion group and 43.4% in the non-fusion group, which were statistically comparable (p = 0.23). We observed no remarkable correlations between cervical sagittal spinal alignment parameters and JOA score recovery rate in the cohort, nor was any significant subluxation progression seen. Conclusion Compared with fusion surgery, surgical decompression alone may be a suitable and less invasive option for the treatment of non-inflammatory retro-odontoid pseudotumor with AAS, especially in elderly patients.

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.

Reducing the number of screw insertions while maintaining good clinical outcomes can improve the efficiency and cost-effectiveness of scoliosis surgery. However, the optimal minimum number of pedicle screws remains unclear. This study searched for factors to estimate the fewest number of pedicle screws required between end vertebrae in relation to preoperative main thoracic curve flexibility.Sixty-nine subjects (4 male and 65 female, mean age: 14.8 ± 2.5 years) who underwent skip pedicle screw fixation for Lenke type 1-4 or 6 curves and were followed for at least 1 year were enrolled. Intervention technique was selected according to the size and flexibility of the preoperative main thoracic curve. Surgery-related variables included pedicle screw number, rod material and diameter, and extent of Ponte osteotomy. The effect on postoperative correction angle (i.e., the difference between the preoperative supine position maximum bending and postoperative standing Cobb angles of the main thoracic curve) according to surgical intervention technique was estimated using multiple linear mixed regression models with the preoperative supine position maximum bending correction angle (i.e., the difference between the standing preoperative and supine position maximum bending Cobb angles) as a random effect.The preoperative maximum bending correction angle was 8-42° and had a moderate negative correlation with postoperative correction angle (r = -0.65, P 0.01). Multivariate analysis revealed a 1.7° (95% CI 0.7-2.6; P 0.01) correction gain per single-screw insertion and a 1.8° (95% CI 0.5-3.1; P 0.01) gain per intervertebral level in Ponte osteotomy.The number of pedicle screws necessary to correct main thoracic adolescent idiopathic scoliosis curves can be estimated by calculating correction gains of 1.7° per pedicle screw and 1.8° per Ponte osteotomy intervertebral level. Based on these results, it may be possible to reduce invasiveness and cost for patients requiring a smaller degree of correction.

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

Skip pedicle screw fixation for adolescent idiopathic scoliosis (AIS) requires fewer screws and can reduce the risk of neurovascular injury as compared with segmental pedicle screw fixation. However, the long-term impact of screw number reduction on correction and clinical results is unclear. This study examined the 10-year post-operative outcomes of skip pedicle screw fixation for patients with AIS. We reviewed the outcomes of 30 patients who underwent skip pedicle screw fixation for AIS. Radiological and clinical findings were assessed before and immediately, 2 years, and 10 years after surgery in the remaining 25 patients. The mean Cobb angle of the main curve preoperatively and immediately, 2 years, and 10 years post-operatively was 59.4&deg, 23.4&deg, 25.8&deg, and 25.60&deg, respectively, and was significantly improved at all post-surgical time points (all p &lt, 0.001). The mean correction rate immediately after surgery was 60.8%, and the correction loss rate at the observation end point was 4.8%. The Cobb angle of the lumbar curve was significantly improved immediately after surgery, and the correction persisted until 10 years post-operatively. Remarkable gains were observed for most Scoliosis Research Society-22 patient questionnaire sub-scores at the final follow-up versus preoperative assessments. In conclusion, good correction of the AIS deformity by skip pedicle screw fixation was well maintained over a long follow-up period of 10 years, with clinically meaningful gains in Society-22 patient questionnaire sub-scores.

OBJECTIVE For instrumented correction surgery for adolescent idiopathic scoliosis (AIS), surgeons are increasingly switching from titanium (Ti) alloy rods to stiffer cobalt-chromium (CoCr) rods. The authors conducted the first multicenter randomized controlled clinical trial to investigate whether these materials affect the outcomes in terms of spine correction and quality of life (QOL). This trial was registered at UMIN Clinical Trials Registry on September 3, 2012, under the identifier UMIN000008838 (level of evidence 1). METHODS Female AIS patients (Lenke types 1–3, patient age 10–19 years) were recruited at 5 Japanese institutions and randomized into two cohorts: 6.0-mm-diameter Ti rods were placed in one group, and 6.0-mm-diameter CoCr rods were placed in the other. Patients were followed up at 2 weeks and 3, 6, and 12 months with radiographic examination to quantify the sagittal and coronal correction (Cobb angle, thoracic kyphosis, rib hump, and apical vertebral rotation). Patients completed questionnaires (Scoliosis Research Society–22r, 12-Item Short-Form Health Survey, and Scoliosis Japanese Questionnaire–27) at 6 and 12 months to assess QOL. RESULTS A total of 69 AIS patients were randomized to the demographically similar Ti (n = 37) or CoCr (n = 32) cohort. Four adverse events were recorded, two in each cohort, but these were not related to the rod material. At the final follow-up, both Ti and CoCr cohorts showed significant improvement in spinal correction, including the Cobb angle, thoracic kyphosis, and rib hump size. The correction rates were 68.4% and 67.1% for the Ti and CoCr cohorts, respectively. No parameters differed significantly between the cohorts at any time. Survey data showed improved but similar outcomes in both cohorts. CONCLUSIONS Both treatments (Ti and CoCr) produced similar results and were efficient in engendering clinically significant spine corrections. Clinical trial registration no.: UMIN000008838 (UMIN Clinical Trials Registry)

BACKGROUND CONTEXT The minimally invasive (MI) approach in posterior lumbar interbody fusion (PLIF) minimizes the muscle-stripping posterior exposure of the lumbar spine; therefore, it is hypothesized that such benefits would reduce adjacent segment pathology (ASP) development. OBJECTIVE This study aimed to estimate the incidence of ASP following MI-PLIF. STUDY DESIGN Retrospective study. PATIENT SAMPLE A total of 100 patients who had undergone single-level PLIF at the L4/5 level for lumbar degenerative spondylolisthesis were retrospectively studied (MI-PLIF group: 68 patients; conventional open PLIF [O-PLIF] group; 32 patients; average follow-up period: 100.5 months). OUTCOME MEASURES Incidence of ASP. METHODS Patients were considered to have operative ASP (OASP) if adjacent segments manifested degenerative lesions that caused clinically significant symptoms requiring surgery. Survival curves were estimated for each group using the Kaplan–Meier method. The study was not externally funded. The authors have no conflicts of interest to declare. RESULTS Four (5.9%) of the 68 patients in the MI-PLIF group and 6 (18.8%) of the 32 patients in the O-PLIF group experienced OASP during the follow-up period. Kaplan–Meier analysis predicted a disease-free OASP survival rate of 98.5% (95% confidence interval [CI], 95.5%–100%) in the MI-PLIF group and 90.6% (95% CI, 81.1%–100%) in the O-PLIF group at 5 years, and 93.7% (95% CI, 86.8%–100%) in the MI-PLIF group and 71.8% (95% CI, 52.9%–97.5%) in the O-PLIF group at 10 years. MI-PLIF achieved a significantly higher survival rate in OASP than did O-PLIF (p=.04). O-PLIF was associated with a 3.97 times higher risk (odds ratio 3.97, 95% CI, 1.02–15.48; p=.04) of developing OASP in our cohort. CONCLUSIONS Following MI-PLIF, the rate of OASP was predicted to be 1.5% at 5 years and 6.3% at 10 years. MI-PLIF had a lower incidence of OASP and more favorable clinical outcomes than did O-PLIF.

Background Goldenhar syndrome sometimes displays progressive scoliosis and other spinal deformities that require treatment. However, few reports exist on scoliosis correction in Goldenhar syndrome. We described the rare radiological outcomes of a patient with Goldenhar syndrome who received brace treatment for scoliosis. Case presentation A 4-year-old boy was diagnosed as having Goldenhar syndrome and referred to our hospital for scoliosis treatment. The deformity deteriorated gradually, and left convex scoliotic angle was 26 degrees (T3-L2) at 11 years of age. Unexpectedly during treatment with an orthopedic brace, the curve had reversed to 21 degrees (T5-L2) at 7 months of therapy. After another adjustment of the brace, his right convex scoliotic angle improved to 13 degrees (T4-L2) at 15 months of treatment. Conclusions Curve reversal may occur during brace treatment for scoliosis in Goldenhar syndrome. Clinicians may opt to periodically check curve correction despite the risk of increased radiation exposure.

Study design A retrospective single-center and single-surgeon study. Objective This study investigated the screw perforation rate according to main curve flexibility in pedicle screw fixation using a computed tomography (CT) guidance for adolescent idiopathic scoliosis (AIS). Summary of background The authors have been using a CT-based navigation system during pedicle screw insertion for AIS to avoid serious neurovascular or visceral structure injury but suspect that high main curve flexibility may account for some breaches. Data Seventy-two consecutive patients with AIS Lenke type 1 or 2 who had undergone pedicle screw fixation using a CT-based navigation system between February 2008 and April 2018 were retrospectively reviewed. Materials and methods The authors evaluated the perforation rate of pedicle screws inserted into the main thoracic curve between the upper-end and lower-end vertebrae for factors associated with screw violations using multivariate logistic regression mixed models. Results A total of 723 pedicle screws were inserted into the T4-T12 vertebrae with the aid of CT-based navigation. The respective grade 3 perforation rates according to main curve flexibility were 0%-30%: 3.2%; 30%-55%: 1.1%; 55%-75%: 5.2%; and 75%-100%: 5.5%. Main curve flexibility of ≥55% was significantly associated with grade 3 screw perforations (P=0.02). Conclusions Main curve flexibility of ≥55% was significantly related to screw violation in AIS surgery. Greater care is thus advised for screw insertion using CT navigation in AIS with main curve flexibility ≥55%.

Spinal deformity is a characteristic feature of Loeys-Dietz syndrome (LDS). Surgical correction in LDS is indicated when the deformity is progressive to avoid neurological deficits, respiratory impairment, and back pain. However, few reports exist on the surgical treatment of spinal deformity in LDS, and no therapeutic standards have been established. We described the clinical and radiological outcomes of a patient with LDS receiving surgery for severe kyphoscoliosis. A 21-year-old male patient with LDS underwent posterior spinal fusion with an all-pedicle screw construct from T10 to L5 for a preoperative main curve Cobb angle of 70 degrees and kyphotic angle of 49 degrees. The postoperative Cobb angle of the main curve and kyphotic angle improved to 36 and 8 degrees, respectively. Correction surgery was performed with frequent motor evoked potential testing, taking care not to cause motor paralysis. Ameliorated low back pain and improvements in clinical questionnaire scores were noted at 21 months after surgery. No perioperative complications were reported. Based on the present case, posterior spinal fusion represents a good correction option for severe spinal deformity in LDS with syringomyelia. Careful preoperative examination and treatment for neurovascular and neurological lesions is advised to prevent severe complications.

This study investigated whether postoperative rotational deformity in adolescent idiopathic scoliosis patients could be predicted by prone-position pre-operative angle of trunk rotation (ATR). Surgical rib hump correction is performed with the patient in a prone position. However, the association between pre-operative ATR in the prone position and postoperative ATR results is unknown. Thirty-four consecutive patients who underwent skip pedicle screw fixation for Lenke type 1 or 2 adolescent idiopathic scoliosis were retrospectively reviewed. All subjects were followed for a minimum of 1 year. ATR measurements were taken for the standing-flexion position with a scoliometer before surgery and at 1 year afterward. Pre-operative measurements were also taken for the prone position. Correlations between pre- and postoperative ATR were calculated by means of Pearson correlation coefficient. Associations between the correction angle from the standing-flexion position to prone position and postoperative standing-flexion correction angle were determined by linear regression analysis. Pre- and postoperative ATR for the standing-flexion position showed a moderate association (r = 0.64, P

In skip pedicle screw fixation for adolescent idiopathic scoliosis (AIS), the mid-term effects of reducing screw number on correction and clinical results are uncertain. We clarified the mid-term outcomes of this technique in patients with Lenke type 1 and 2 AIS.Thirty-four patients who underwent skip pedicle screw fixation (mean screw density: 1.35 screws) for Lenke type 1 and 2 AIS were retrospectively reviewed. The follow-up period was at least 5 years (mean follow-up period: 6.1 years), and the follow-up rate was 89.5%. Radiological parameters and clinical symptoms were evaluated before, immediately after, and at 2 years and 5 years after surgery.The mean Cobb angle of the main thoracic (MT) curve before, immediately after, at 2 years after surgery, and at the final 5-year minimum follow-up was 52.5°, 16.4°, 20.5°, and 19.4°, respectively. The Cobb angle of the MT curve was significantly improved immediately after, at 2 years after surgery, and at the final follow-up compared with that before surgery (p 0.01). The mean correction rate immediately after surgery was 69.0% and the rate of correction loss at the final follow-up was 8.3%. All Scoliosis Research Society-22 patient questionnaire (SRS-22r) sub scores 5 years after surgery were significantly improved compared with those beforehand (p 0.01).Correction using skip pedicle screw fixation in AIS was well maintained from the initial follow-up measurements to the final follow-up. The SRS-22r sub scores at the final follow-up were significantly improved over preoperative levels.

It is generally recognized that the main thoracic curve Cobb angle threshold for surgical correction is approximately 50 degrees in patients with adolescent idiopathic scoliosis (AIS). Although AIS with a Cobb angle of50 degrees is sometimes treated surgically to improve cosmesis, the precise outcomes are unclear. This study analyzed the postoperative results for AIS with a main thoracic curve of 50 degrees.Thirty-nine consecutive patients with Lenke type 1-2 curves underwent posterior spinal fusion for AIS. These subjects were divided into the50 degrees of main thoracic curve group (n = 14) and the ≥50 degrees group (n = 25). Clinical and radiographic data were compared.The mean Cobb angle of the main thoracic curve before and at 2 years after surgery for the50 degrees and ≥50 degrees groups was 44.5 and 60.3 degrees (p 0.001) and 14.0 and 19.5 degrees (p = 0.016), respectively. Preoperatively, both groups had comparable Scoliosis Research Society-22 (SRS-22) scores (all p 0.05). Patients with a Cobb angle of50 degrees displayed significantly milder postoperative pain (4.7 vs. 4.3, p = 0.031), with no remarkable differences in other SRS-22 domain scores. These patients also had a significantly shorter operative time (194 vs. 235 min, p = 0.021) and fused level (9.2 vs. 10.8 vertebrae, p = 0.006) along with similar correction rate (68.1 vs. 65.8%, p = 0.622) and blood loss volume (932 vs. 1009 ml, p = 0.715).Surgical correction of AIS with50 degrees of main thoracic curve may less invasively achieve results that are comparable with those for AIS with 50 degrees or more, including improvements in self-image.

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.