藤田 順之

STUDY DESIGN: Retrospective study. OBJECTIVES: The combination of oblique lateral interbody fusion (OLIF) with grade 2 posterior column osteotomy (PCO) is an effective treatment for adult spinal deformity. However, grade 2 PCO may lead to pseudoarthrosis because it involves complete removal of the bilateral posterior facet joints. The main study objective was to determine the achievement rate of anterior and posterolateral fusion resulting in circumferential fusion in patients who underwent combined OLIF and grade 2 PCO. METHODS: This retrospective study included consecutive patients who underwent OLIF and grade 2 PCO. The group comprised a long fusion group, with fusion from the thoracic level to the ilium, and a short fusion group, with fusion within the lumbar region. The OLIF with percutaneous pedicle screw insertion group was also used for reference. The Brantigan-Steffee-Fraser classification was used to assess interbody fusion and Lenke classification for assessment of posterolateral fusion. RESULTS: Sixty-six patients with 109 lumbar levels were included in the study. We observed 100% anterior fusion in all 3 groups. The fusion rate for posterolateral fusion between the OLIF-grade 2 PCO group was 97%, with very low (3%) non-circumferential fusion (pseudoarthrosis only at the osteotomy site). In most cases, solid posterolateral fusions (Lenke A) occurred within 24 months. CONCLUSIONS: The combination of OLIF and grade 2 PCO resulted in circumferential fusion for most (97%) of the cases within 24 months. OLIF and grade 2 PCO are considered a good combination treatment to achieve sufficient lumbar lordosis and solid bone fusion.

BACKGROUND: Extreme lateral interbody fusion (XLIF) is often used with posterior spinal fixation (PSF) to treat adult spinal deformity (ASD). However, the amount of intraoperative blood loss (IBL) reported for XLIF may underestimate the total blood loss (TBL). The objective of this study was to determine the total perioperative blood loss in XLIF for ASD. METHODS: We assessed 30 consecutive ASD patients with Schwab-SRS type L (mean age: 68.7 ± 8.2 years; mean follow-up 2.0 ± 1.3 years) who were treated by multilevel XLIF (mean, 2.5 ± 0.6 levels) followed by PSF after 3-5 days. We calculated the TBL after XLIF by the Gross equation, by hemoglobin (Hb) balance, and by the Orthopedic Surgery Transfusion Hemoglobin European Overview (OSTHEO) formula. We defined hidden blood loss (HBL) as the difference between the TBL and IBL. Pearson correlation, Spearman correlation, and multiple logistic regression analysis were performed to investigate the risk factors related to HBL. RESULTS: Post-XLIF blood tests showed a significant decrease in the Hb (from 11.8 ± 1.1 mg/dl to 10.6 ± 1.1 mg/dl) and hematocrit (from 36.0 ± 3.2% to 32.5 ± 3.2%). Although the mean IBL was relatively small (33 ± 52 mL), we calculated the TBL as 291 ± 171 mL (Gross equation) and the HBL as 258 ± 168 mL by Gross equation, which was 8 times greater than the IBL on average. There was no difference in the results obtained using the three methods. Multiple logistic regression analysis indicated preoperative lumber lordosis was the risk factor of high HBL (Odds ratio = 1.085, 95%CI: 1.006-1.170, p = 0.035). CONCLUSIONS: The HBL in XLIF was 8 times greater than the IBL. During the perioperative course of correction and fusion surgery for ASD with XLIF, surgeons need to pay attention not to underestimate the TBL.

INTRODUCTION: Gliofibroma is a rare tumor that develops in the brain and spinal cord. Due to the rarity of its nature, its pathophysiology and appropriate treatment remain elusive. We report a case of intramedullary spinal cord gliofibroma that was surgically treated multiple times. This report is of great significance because this is the first case of recurrence of this tumor. CASE PRESENTATION: A 32-year-old woman complained of gait disturbance and was referred to our institution. At the age of 13 years, she was diagnosed with intramedullary gliofibroma and underwent gross total resection (GTR) in another hospital. Based on imaging findings, tumor recurrence was suspected at the level of cervical spinal cord, and surgery was performed. However, the resection volume was limited to 50% because the boundary between the tumor and spinal cord tissue was unclear and intraoperative neuromonitoring alerted paralysis. At 1 year postoperatively, the second surgery was performed to try to resect the residual tumor, but subtotal resection was achieved at most. At 2 years after the final surgery, no tumor recurrence was observed, and neurologic function was maintained to gait with cane. DISCUSSION: Although complete resection is desirable for this rare tumor at the initial surgery, there is a possibility to recur even after GTR with long-term follow-up. During surgical treatment for tumor recurrence, fair adhesion to the spinal cord is expected, and reoperation and/or adjuvant therapy might be considered in the future if the tumor regrows and triggers neurological deterioration.

BACKGROUND: The complication rate for palliative surgery in spinal metastasis is relatively high, and major complications can impair the patient's activities of daily living. However, surgical indications are determined based primarily on the prognosis of the cancer, with the risk of complications not truly considered. We aimed to identify the risk predictors for perioperative complications in palliative surgery for spinal metastasis. METHODS: A multicentered, retrospective review of 195 consecutive patients with spinal metastasis who underwent palliative surgeries with posterior procedures from 2001 to 2016 was performed. We evaluated the type and incidence of perioperative complications within 14 days after surgery. Patients were categorized into either the complication group (C) or no-complication group (NC). Univariate and multivariate analyses were used to identify potential predictors for perioperative complications. RESULTS: Thirty patients (15%) experienced one or more complications within 14 days of surgery. The most frequent complications were surgical site infection (4%) and motor weakness (3%). A history of diabetes mellitus (C; 37%, NC; 9%: p < 0.01) and surgical time over 300 min (C; 27%, NC; 12%: p < 0.05) were significantly associated with complications according to univariate analysis. Increased blood loss and non-ambulatory status were determined to be potential risk factors. Of these factors, multivariate logistic regression revealed that a history of diabetes mellitus (OR: 6.6, p < 0.001) and blood loss over 1 L (OR: 2.7, p < 0.05) were the independent risk factors for perioperative complications. There was no difference in glycated hemoglobin A1c between the diabetes patients with and without perioperative complications. CONCLUSIONS: Diabetes mellitus should be used for the risk stratification of surgical candidates regardless of the treatment status, and strict prevention of bleeding is needed in palliative surgeries with posterior procedures to mitigate the risk of perioperative complications.

STUDY DESIGN: This is a retrospective observational study with an outpatient setting. PURPOSE: This study aimed to describe the effects of duloxetine (DLX) administration for postsurgical chronic neuropathic disorders (both pain and numbness) following spinal surgery in patients without depression. OVERVIEW OF LITERATURE: Although several reports indicated the potential of DLX to effectively treat postoperative symptoms as a perioperative intervention, there have been no reports of its positive effect on postsurgical chronic neuropathic disorders. METHODS: A total of 24 patients with postsurgical chronic pain and/or numbness Numeric Rating Scale (NRS) scores of ≥4 were enrolled. All patients underwent spine or spinal cord surgery at Keio University Hospital and received daily administration of DLX for more than 3 months. The mean postoperative period before the first administration of DLX was 35.5±57.0 months. DLX was administered for more than 3 months at a dose of 20, 40, or 60 mg/day, and the degree of pain and numbness was evaluated using the NRS before administration and 3 months after administration. Effectiveness was defined as more than a 2-point decrease in the NRS score following administration. RESULTS: In terms of the type of symptoms, 15 patients experienced only numbness, eight experienced both pain and numbness, and one experienced only pain. Of the 24 patients, 19 achieved effective relief with DLX. DLX was effective for all patients with postsurgical chronic pain (n=9), and it reduced postsurgical chronic numbness in 18 of 23 patients. No significant difference was observed in background spinal disorders. DLX was not effective for five patients who complained only of postsurgical chronic numbness. CONCLUSIONS: This study reports the effectiveness of DLX for postsurgical chronic neuropathic disorders. Although DLX reduced postsurgical chronic pain (efficacy rate=100%) and numbness (78.3%) in certain patients, further investigation is needed to determine its optimal use.

Hyaluronic acid (HA) is widely recognized as a therapeutic target and currently used in medicine. However, HA metabolism during intervertebral disc degeneration (IVDD) has not been completely elucidated. This study aimed to evaluate the efficacy of HA on intervertebral disc (IVD) inflammation and identify the main molecules modulating HA degradation in IVDs. To assess HA function in IVD cells in vitro, we treated human disc cells and U-CH1-N cells, a notochordal nucleus pulposus cell line, with HA or hyaluronidase. Real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis showed that tumor necrosis factor alpha (TNF-α)-mediated induction of the expression of TNF-α and cyclooxygenase-2 (COX2) was clearly neutralized by HA treatment, and the expression of TNF-α and COX2 was significantly induced by hyaluronidase treatment in both cell types. Additionally, Western blot analysis showed that hyaluronidase-induced phosphorylation of p38 and Erk1/2, and that TNF-α-mediated phosphorylation of p38 and Erk1/2 was clearly reduced by HA addition. In degenerating human IVD samples, immunohistochemistry for hyaluronidase showed that the expression of hyaluronidases including HYAL1, HYAL2, and cell migration-inducing protein (CEMIP) tended to increase in accordance with IVDD. In particular, HYAL1 showed statistically significant differences. In vitro study also confirmed a similar phenomenon that TNF-α treatment increased both messenger RNA and protein expression in both cell types. Our results demonstrated that HA could potentially suppress IVDD by regulating p38 and Erk1/2 pathways, and that the expression of HYAL1 was correlated with IVDD progression. These findings indicated that HYAL1 would be a potential molecular target for suppressing IVDD by controlling HA metabolism.

STUDY DESIGN: A retrospective comparative study. OBJECTIVE: The aim of this study was to examine the changes in cervical sagittal alignment (CSA) following surgical correction in a patient with Lenke type 5 adolescent idiopathic scoliosis (AIS) and evaluate any possible factors influencing postoperative CSA. SUMMARY OF BACKGROUND DATA: Few studies have assessed the association between CSA and thoracic or lumbar sagittal alignment in AIS patients with major thoracolumbar/lumbar curve who underwent posterior correction and fusion surgery. METHODS: Sixty-six patients with Lenke type 5 AIS (two males and 64 females, the mean age at surgery of 16.2 years) were included in this study. They were followed up for minimum 5 years after surgery. Multiple linear regression analysis was used to evaluate possible factors influencing the postoperative CSA. To determine the influence of upper end vertebra (UEV) level on postoperative CSA, the subjects were divided into two groups according to UEV level of ≥T9 or ≤T10. The outcome variables were compared between the two groups and analyzed for changes in various spinal sagittal profiles using radiographic outcomes. RESULTS: Multiple linear regression analysis revealed that preoperative T10-L2 kyphosis and LL were significantly correlated with postoperative C2-7 lordosis. However, CSA did not significantly change at 5 years after surgery. Sub-analysis of the cohort revealed that in the UEV ≥T9 group, the mean thoracic kyphosis significantly increased from 20.3° ± 10.6° to 24.0° ± 8.9° and the mean C2-7 lordosis also significantly increased from -12.5° ± 8.3° to -4.3° ± 10.3° at 5-year postoperatively. SRS-22 outcomes were comparable between the groups. CONCLUSION: We indicated that the CSA was not influenced by surgical correction in most Lenke type 5 AIS patients. However, in a patient whose UEV was located at T9 or higher levels, CSA was influenced through the changes in thoracic kyphosis following posterior correction surgery.Level of Evidence: 4.

CASE: A 14-year-old adolescent boy with congenital kyphoscoliosis with T5 hemivertebra visited our hospital complaining gait disturbance. The T5 hemivertebra was resected posteriorly, and kyphosis at T4 to T7 was corrected from 43° to 36°. However, neurological status gradually deteriorated after surgery. Surgery to reduce kyphosis by bending the rods was performed with intraoperative ultrasonography, which resulted in spinal cord decompression and repulsation of the spinal cord. The muscle strength of the lower extremities improved immediately after surgery. CONCLUSION: Correction surgery for congenital kyphoscoliosis has high risk of perioperative neurological deterioration. Ultrasonography may be a useful tool for monitoring status of the spinal cord.

BACKGROUND: Musculoskeletal disorders are a key cause of morbidity in elderly people. How musculoskeletal disorders relate to healthy life expectancy remain elusive. Hence, we aimed to estimate gains in healthy life expectancy from the elimination of musculoskeletal diseases and injuries by using recent national health statistics data in Japan. METHODS: Mortality data were taken from Japanese national life tables and death certificates in 2016. Information on medical diagnoses, injuries, and activity were obtained from the 2016 Comprehensive Survey of Living Conditions. We examined five disorders: rheumatoid arthritis, arthrosis, low back pain, osteoporosis, and fracture. The prevalence of limitations in activities of daily living (ADL) in the population after eliminating the disorder was estimated as the proportion of outpatients without the disorder and ADL limitations, inpatients without the disorder in hospitals and clinics, and people without the disorder who reside in long-term elderly care facilities. RESULTS: There were small gains in life expectancy from elimination of all selected musculoskeletal disorders (0.0-0.1 years). Elimination of rheumatoid arthritis, osteoporosis, and fracture slightly increased the expected years without activity limitation (0.1-0.4) and slightly decreased years with activity limitation (0.1-0.4 years). Meanwhile, elimination of arthrosis, low back pain, and arthrosis and low back pain moderately increased expected years without activity limitation (0.3-1.5 years) and decreased years with activity limitation (0.3-1.5 years). In addition, elimination of rheumatoid arthritis, arthrosis, low back pain, osteoporosis, and fracture decreased expected years with ADL limitations (0.0-0.8 years) and non-ADL limitations (0.0-0.3 years). A combination of arthrosis and low back pain showed a moderate decrease in expected years with both ADL limitations (0.7-1.1 years) and non-ADL limitations (0.3-0.4). CONCLUSIONS: These findings provide clinical evidence that among the musculoskeletal disorders low back pain and arthrosis are the key factors for the elongation of healthy life expectancy.

Adolescent idiopathic scoliosis (AIS) is a common disease causing three-dimensional spinal deformity in as many as 3% of adolescents. Development of a method that can accurately predict the onset and progression of AIS is an immediate need for clinical practice. Because the heritability of AIS is estimated as high as 87.5% in twin studies, prediction of its onset and progression based on genetic data is a promising option. We show the usefulness of polygenic risk score (PRS) for the prediction of onset and progression of AIS. We used AIS genomewide association study (GWAS) data comprising 79,211 subjects in three cohorts and constructed a PRS based on association statistics in a discovery set including 31,999 female subjects. After calibration using a validation data set, we applied the PRS to a test data set. By integrating functional annotations showing heritability enrichment in the selection of variants, the PRS demonstrated an association with AIS susceptibility (p = 3.5 × 10-40 with area under the receiver-operating characteristic [AUROC] = 0.674, sensitivity = 0.644, and specificity = 0.622). The decile with the highest PRS showed an odds ratio of as high as 3.36 (p = 1.4 × 10-10 ) to develop AIS compared with the fifth in decile. The addition of a predictive model with only a single clinical parameter (body mass index) improved predictive ability for development of AIS (AUROC = 0.722, net reclassification improvement [NRI] 0.505 ± 0.054, p = 1.6 × 10-8 ), potentiating clinical use of the prediction model. Furthermore, we found the Cobb angle (CA), the severity measurement of AIS, to be a polygenic trait that showed a significant genetic correlation with AIS susceptibility (rg = 0.6, p = 3.0 × 10-4 ). The AIS PRS demonstrated a significant association with CA. These results indicate a shared polygenic architecture between onset and progression of AIS and the potential usefulness of PRS in clinical settings as a predictor to promote early intervention of AIS and avoid invasive surgery. © 2021 American Society for Bone and Mineral Research (ASBMR).

BACKGROUND: Chemonucleolysis with condoliase, which degrades chondroitin sulfate, could be a new, minimally invasive therapeutic option for patients with lumbar disc herniation (LDH). The purpose of this study was to analyze prognostic factors for clinical outcomes in LDH patients subjected to chemonucleolysis with condoliase. METHODS: Inclusion criteria for this procedure were 1) 18-70 years of age; 2) unilateral leg pain and positive straight leg raise (SLR) (<70°) or femoral nerve stretching test; 3) subligamentous extrusion verified on magnetic resonance imaging; 4) neurological symptoms consistent with a compressed nerve root on magnetic resonance imaging (MRI) images; and 5) minimum six months of follow-up. In total, 82 patients (55 men, 27 women; mean age, 47.2 ± 15.5 years; mean follow-up, 9.1 ± 3.0 months) who underwent chemonucleolysis with condoliase for painful LDH were included. An improvement of 50% or more in the Visual analogue scale (VAS) of leg pain was classified as effective. RESULTS: Seventy patients (85.4%) were classified into the effective (E) group and 12 patients (14.6%) into the less-effective (L) group. Surgical treatment was required in four patients. No severe adverse complications were reported; 41.3% of the patients developed disc degeneration of Pfirrmann grade 1 or more at the injected disc level. Univariate analysis revealed that young age (p = 0.036), without history of epidural or nerve root block (p = 0.024), and injection into the central portion of the intervertebral disc (p = 0.014) were significantly associated with clinical effectiveness. A logistic regression analysis revealed that injection into the central portion of the intervertebral disc (p = 0.049; odds ratio, 4.913; 95% confidence interval, 1.006-26.204) was significantly associated with clinical effectiveness. CONCLUSIONS: Chemonucleolysis with condoliase is a safe and effective treatment for painful LDH; 85.4% of the patients showed improvement after the treatment without severe adverse events. To obtain the best outcome, condoliase should be injected into the center of the intervertebral disc.

BACKGROUND: Although several causes of ligamentum flavum (LF) hypertrophy have been identified, the pathomechanisms underlying LF hypertrophy are not fully understood. Because collagen fibers are essential for the maintenance of LF tissues, characterization of the collagen composition of hypertrophied LF may help to elucidate the pathology of lumbar spinal canal stenosis (LCS). This study aimed to determine the association between the collagen composition and LF hypertrophy. METHODS: LF tissues were collected from 23 patients who underwent spinal decompression surgery for lumbar disorders. The cross-sectional area of LF was measured using the axial images of lumbar MRI. The expression of each collagen in human surgical samples was evaluated by real-time RT-PCR and immunohistochemical analysis. To investigate the impact of inflammatory cytokines on the expression of each collagen, we treated primary human LF cells with TNF-α or IL-1β. RESULTS: Real-time RT-PCR analysis and immunohistochemistry showed that of the 28 types of collagen, collagen type I, III, V, VI, VIII were highly expressed regardless of LF hypertrophy. In addition, we found the moderate correlation between the cross-sectional area of LF and the mRNA expression level of collagen type I, III, and VI. In vitro analysis showed that the mRNA expression of collagen type I, III, V, VI, and VIII was up-regulated by treatment with TNF-α and with IL-1β. CONCLUSION: Our results suggested that collagen type I, III, V, VI, and VIII were the main components of the LF extracellular matrix and that collagen type I, III, and VI may serve as useful markers of LF hypertrophy. These findings may contribute to the future development of diagnostic and treatment modalities for LF hypertrophy and even LCS.

STUDY DESIGN: Retrospective review of 159 surgically treated consecutive adult symptomatic lumbar deformity (ASLD) (65 ± 9 years, female: 94%) from a multicenter database. OBJECTIVE: The aim of this study was to provide a comprehensive analysis of the risk of a poor clinical outcome in ASLD surgery. SUMMARY OF BACKGROUND DATA: Poor-risk patients with ASLD remain poorly characterized. METHODS: ASLD was defined as age >40 years with a lumbar curve ≥30° or C7SVA ≥5 cm and Scoliosis Research Society 22 (SRS22) pain or function <4. Poor outcome was defined as 2y SRS22 total <4 or pain, function or satisfaction ≤3. The outcomes of interest included age, sex, body mass index, bone mineral density, Schwab-SRS type, frailty, history of arthroplasty, upper-instrumented vertebral, lower-instrumented vertebral, levels involved, pedicle subtraction osteotomy, lumbar interbody fusion, sagittal alignment, global alignment and proportion (GAP) score, baseline SRS22r score, estimated blood loss, time of surgery, and severe adverse event (SAE). Poisson regression analyses were performed to identify the independent risks for poor clinical outcome. A patient was considered at poor risk if the number of risks was >4. RESULTS: All SRS22 domains were significantly improved after surgery. In total, 21% (n = 34) reported satisfaction ≤3 and 29% (n = 46) reported pain or function ≤3. Poisson regression analysis revealed that frailty (odds ratio [OR]: 0.2 [0.1-0.8], P = .03), baseline mental-health (OR: 0.6 [0.4-0.9], P = .01) and function (OR: 1.9 [1.0-3.6], P < .01), GAP score (OR: 4.6 [1.1-18.7], P = .03), and SAE (OR: 3.0 [1.7-5.2], P < .01) were identified as independent risk for poor clinical outcome. Only 17% (n = 6) of the poor-risk patients reached SRS22 total score >4.0 at 2 years. CONCLUSION: The overall clinical outcome was favorable for ASLD surgery. Poor-risk patients continue to have inferior outcomes, and alternative treatment strategies are needed to help improve outcomes in this patient population. Recognition and optimization of modifiable risk factors, such as physical function and mental health, and reduced SAEs may improve overall clinical outcomes of ASLD surgery.Level of Evidence: 3.

STUDY DESIGN: Retrospective single-center study. OBJECTIVE: We investigated the risk factors of postoperative shoulder imbalance (PSI) in patients with Lenke type 2 adolescent idiopathic scoliosis (AIS) including the position of preoperative upper end vertebra (UEV). METHODS: Seventy-five patients with Lenke type 2 AIS who underwent posterior correction and fusion surgeries from 2008 to 2018 were included. We included only patients whose upper instrumented vertebrae were at T2. The patients were divided into 2 groups based on radiographic shoulder height (RSH) at final follow-up, namely PSI group and non-PSI group, and PSI was defined as RSH > 10 mm. UEV, RSH, Cobb angle, curve flexibility, T1 and T2 tilt, correction rate, Risser grade, Scoliosis Research Society-22 scores, and demographic data were compared between the groups using independent t-tests or chi-square tests. Variables with P value < 0.20 in univariate analysis were assessed in logistic regression analysis. RESULTS: Thirty-four patients in the PSI group and 37 patients in the non-PSI group were analyzed. Univariate analysis revealed that there were more patients with UEV at T1 (PSI: 85%, non-PSI: 54%, P < 0.01) and Risser grade ≥ 3 (PSI: 88%, non-PSI: 62%; P < 0.05) in the PSI group than in the non-PSI group. Logistic regression analysis revealed that UEV at T1 (odds ratio [OR] = 4.1 [1.2-14.4], P < 0.05) and Risser grade ≥ 3 (OR = 3.9 [1.1-14.5], P < 0.05) are significantly associated with PSI. CONCLUSIONS: UEV at T1 and Risser grade ≥ 3 at the time of surgery are significant risk factors of PSI.

CASE: A 22-year-old skeletally mature man with scoliosis accompanied by syringomyelia associated with Chiari malformation type 1 was presented to our hospital. Because the maximal syrinx/cord ratio was small, and he had no neurological deficit, he underwent corrective surgery without the treatment of the syringomyelia. CONCLUSION: The scoliosis was corrected without any neurological complications. Magnetic resonance imaging taken 8 days after the surgery showed the reduction of the size of the syringomyelia. The syringomyelia almost disappeared at the 8-year follow-up.

BACKGROUND: Although the incidence of symptomatic pulmonary thromboembolism after elective surgery for degenerative musculoskeletal disorders is comparatively low, it is extremely detrimental to both patients and health-care providers. Therefore, its prevention is mandatory. We aimed to perform a cross-sectional analysis of deep venous thrombosis (DVT) before elective surgery for degenerative musculoskeletal disorders, including total knee arthroplasty (TKA), total hip arthroplasty (THA), and spinal surgery, and identify the factors associated with the incidence of preoperative DVT. METHODS: The clinical data of patients aged ≥ 30 years who underwent TKA or THA, and spine surgery for lumbar or cervical degenerative disorders at our institution were retrospectively collected. D-dimer levels were measured preoperatively in all the patients scheduled for surgery. For the patients with D-dimer levels ≥ 1 µg/mL or who were determined by their physicians to be at high risk of DVT, the lower extremity vein was preoperatively examined for DVT on ultrasonography. RESULTS: Overall, we retrospectively evaluated 1236 consecutive patients, including 701 men and 535 women. Of the patients, 431 and 805 had D-dimer levels ≥ 1 and < 1 µg/mL, respectively. Of 683 patients who underwent lower extremity ultrasonography, 92 had proximal (n = 7) and distal types (n = 85) of DVT. The preoperative prevalence of DVT was 7.4 %. No patient had the incidence of postoperative symptomatic venous thromboembolism. A multivariate analysis revealed that age ≥ 80 years (odds ratio [OR], 95 % confidence interval [CI]: 2.8, 1.1-7.3), knee surgery (2.1, 1.1-4.0), American Society of Anesthesiologists (ASA) grade 2 (2.8, 1.2-6.8), ASA grades 3 or 4 (3.1, 1.0-9.4), and malignancy (1.9, 1.1-3.2) were significantly associated with DVT incidence. CONCLUSIONS: This is the first study to conduct a cross-sectional analysis of preoperative DVT data of patients scheduled for elective surgery for degenerative musculoskeletal disorders. Although whether screening for preoperative DVT is needed to prevent postoperative symptomatic pulmonary thromboembolism remains to be clarified, our data suggested that DVT should be noted before surgery in the patients with advanced age, knee surgery, high ASA physical status, and malignancy.

STUDY DESIGN: A longitudinal, 20-year comparative study of patients with whiplash-associated disorders (WAD). OBJECTIVE: The aim of this study was to clarify the long-term impact of WAD on patient symptoms and on magnetic resonance imaging (MRI) findings of the cervical spine, in comparison with asymptomatic volunteers. SUMMARY OF BACKGROUND DATA: The long-term impact of WAD has not been fully elucidated. METHODS: Between 1993 and 1996, we conducted a cross-sectional comparative study of 508 acute WAD patients and 497 asymptomatic volunteers, all of whom underwent MRI on cervical spine and physical examinations. For this 20-year follow-up comparative study, 75 WAD patients and 181 control subjects aged <60 years were recruited from the original cohort. The MRI findings, including discs' signal intensities, posterior disc protrusions, anterior dural compressions, spinal cord disc space narrowing, and foraminal stenoses, were evaluated using two to four numerical grades. The results of the WAD patients and control subjects were compared. RESULTS: In this follow-up, the prevalence of shoulder stiffness (72.0% vs. 45.9%), headache (24.0% vs. 12.2%), and arm pain (13.3% vs. 3.9%) were significantly greater in WAD patients than in control subjects. The multiregression analysis revealed that a history of WAD was associated with shoulder stiffness (odds ratio [OR]: 3.36), headache (OR: 2.39), and arm pain (OR: 3.82). Although MRI findings in WAD patients were more degenerated than in control subjects in the initial study, all MRI findings were similar at the 20-year follow-up. There were no significant correlations between clinical cervical symptoms and progression in each MR finding in either group. CONCLUSION: After 20 years, whiplash injuries significantly impacted the residual symptoms of shoulder stiffness, headache, and arm pain when compared with initially asymptomatic volunteers. The progression of degenerative changes in the cervical intervertebral discs after 20 years revealed no association with existing whiplash injuries, neither did the residual cervical-related symptoms.Level of Evidence: 3.

PURPOSE: To elucidate the influence of spinal deformity in adolescent idiopathic scoliosis (AIS) on lumbar intervertebral disc (IVD) degeneration in adulthood using magnetic resonance imaging (MRI). METHODS: A total of 102 patients (8 men, 94 women; mean age, 31.4 years) who had developed idiopathic scoliosis at the age of 10-18 years and underwent preoperative lumbar spine MRI at the age of ≥ 20 were included in the study. Twenty volunteers (3 men, 17 women; mean age, 33.6 years) without scoliosis were assessed as controls. We divided the adult scoliosis patients into two groups: Group A consisted of patients with lumbar modifier A, and Group BC consisted of those with modifiers B and C. IVD degeneration from L1/2 to L5/S1 was assessed by MRI. The Scoliosis Research Society-22 (SRS-22) patient questionnaire was used in the patients' clinical assessment. RESULTS: There were 40 patients in the Group A and 62 in the Group BC. Compared to the control groups, significant IVD degeneration was observed at L2/3 and L3/4 in Group A, and at all levels except for L5/S1 in Group BC. The proportion of degenerated IVDs patients (Grades 1c and 2) was significantly higher in Group BC than those in Group A at L3/L4 and L4/L5. Furthermore, the severity of IVD degeneration was significantly greater in the group BC than in the group A at all levels, except for L5/S1, especially in patients aged > 30 years. The mean scores of all subdomains in the SRS-22 questionnaire were comparable between the two groups. CONCLUSION: Our study showed that the residual lumbar curvature from AIS may have accelerated IVD degeneration in adulthood, especially in patients aged > 30 years. LEVEL OF EVIDENCE: III.

INTRODUCTION: We investigated the changes in MRI T2 mapping values in subjects with carpal tunnel syndrome (CTS) compared to healthy controls. METHODS: We enrolled 71 patients with CTS and 26 healthy controls. Median nerve T2 values were measured at the distal carpal tunnel, hamate bone, proximal carpal tunnel, and forearm levels. These were compared between patients and controls and correlated with median nerve cross-sectional area (CSA) and nerve conduction measurements. RESULTS: The mean T2 values at the proximal carpal tunnel levels were higher in the CTS group (56.7 ms) than in the control group (51.2 ms, P = .02) and also were higher than at the distal carpal tunnel (51.0 ms, P < .001) and forearm levels (47.6 ms, P < .001). T2 values were not significantly associated with CSA or nerve conduction measurements. DISCUSSION: T2 mapping of the carpal tunnel provides qualitative information on median nerve pathology but does not reflect CTS severity.

CASE: A 4-year-old girl with spastic gait and hand clumsiness who was diagnosed with cervical myelopathy caused by atlantoaxial dislocation and midcervical severe kyphosis associated with chondrodysplasia punctata (CDP). The patient underwent posterior instrumentation and anterior spinal fusion and successful correction with osseous fusion was obtained 8 months after surgery. In addition, the preoperative neurological symptoms were completely recovered. CONCLUSION: Owing to the characteristics of CDP, the treatment for the cervical lesion is extremely complicated. Successful stabilization and improvement of the neurological symptom were achieved by combining posterior and anterior fusion with instrumentation in this case.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: Intraspinal solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) is often misdiagnosed preoperatively as schwannoma or meningioma because its imaging characteristics are not well understood. As postoperative prognosis differs among the 3 lesions, predicting the probability of SFT/HPC preoperatively is essential. Thus, this study investigates the imaging characteristics of SFT/HPC compared with those of schwannoma or meningioma and evaluates surgical outcomes. METHODS: The preoperative imaging findings, tumor resection extent, recurrence and regrowth rates, and neurological improvement were compared between 10 patients with SFT/HPC and 42 patients with schwannoma or 40 patients with meningioma. RESULTS: Most patients with SFT/HPC showed isointensity on both T1- and T2-weighted images compared with patients with schwannoma (P = 0.011 and 0.029, respectively) and no significant difference compared with patients with meningioma (P = 0.575 and 0.845, respectively). Almost all patients with SFT/HPC showed highly uniformizing enhancement patterns, similar to those with meningioma (P = 0.496). Compared with meningioma, SFT/HPC lacked the dural tail sign and intratumoral calcification and exhibited irregular shape. Of the 5 patients who underwent partial resection, 60% exhibited tumor recurrence and regrowth following surgery. CONCLUSIONS: Complete en bloc surgical resection should be attempted in patients with intraspinal SFT/HPC to prevent postoperative recurrence or regrowth. As this tumor is often preoperatively misdiagnosed, we recommend that the imaging findings exhibited in this study should be used to positively suspect SFT/HPC. This will enhance patient outcomes by enabling more appropriate preoperative surgical planning.

CASE: Gorham-Stout disease (GSD) is a rare disorder characterized by progressive localized osteolysis and lymphatic malformation. A 26-year-old woman with GSD presented to our hospital with a Cobb angle of 100° and a kyphosis angle of 88°. Everolimus therapy was initiated to control the disease prior to surgery. After halo-gravity traction for 4 weeks, we performed anterior and posterior spinal fusion. Postoperative computed tomography revealed satisfactory bone union and no significant loss of correction 1 year post-surgery. CONCLUSION: This case suggests that anterior and posterior spinal fusion combined with everolimus therapy can be a therapeutic option for GSD.

Proximal junctional failure (PJF) is considered to be one of the most serious complications after correction surgery with a long construct for adult spinal deformity. Proximal junctional kyphosis (PJK) was first defined as an angle between the lower endplate of the uppermost instrumented vertebra (UIV) and the upper endplate of UIV+2 of 10 degrees or greater, and at least 10 degrees greater than the preoperative measurement. Although PJK has been found to cause no significant clinical symptoms, PJF is regarded as a pathology associated with a fracture of UIV or UIV+1, posterior osseoligamentous disruption, or a pullout of instrumentation at the UIV, and may require revision surgery. The incidence of PJK or PJF is influenced by a variety of factors including the pathology of the deformity, surgical procedures and spinal construct, status of osteoporosis, prophylactic procedures, and the follow-up period. Therefore, the reported incidences of PJK vary widely, from 7.7% to 56%, whereas those of PJF vary widely, from 1.4% to 35%.

OBJECTIVE: Diffuse idiopathic skeletal hyperostosis (DISH) causes spinal ankylosis, which can result in patients suffering specific spinal fractures that lead to a reduction in the activities of daily life in older patients. Currently, DISH is associated with diabetes mellitus and cardiovascular disease; however, the association between DISH and metabolic syndrome has not been established. The purpose of this study was to investigate a potential association between DISH and metabolic syndrome. METHODS: We retrospectively reviewed clinical data from consecutive subjects undergoing the musculoskeletal health medical checkups, and enrolled 327 subjects (174 men and 153 women; mean, 63.4 ± 13.7-years). Subjects who had spinal ankylosis at least 4 contiguous vertebral bodies were classified as the DISH group (n = 39) while the others were part of the non-DISH group (n = 288). The definition of the metabolic syndrome comes from diagnostic criteria used by the Japanese Society for Internal Medicine. Age, sex, body max index (BMI), hematological evaluation, blood pressure, presence of metabolic syndrome, the visceral fat area on abdominal computed tomography, and spinal epidural lipomatosis (SEL) on magnetic resonance imaging were evaluated. RESULTS: Compared to the non-DISH group, in the DISH group, mean age (DISH group, 74.3 years; non-DISH group, 1.9 years; p < 0.001), male prevalence were higher (DISH group, 82.1%; non-DISH group, 49.3%; p < 0.001), and BMI was greater (DISH group, 24.8; non-DISH group, 23.0; p = 0.006). the metabolic syndrome was more frequently observed in DISH group (28.9%) than in the non-DISH group (16.0%) (p = 0.045). The visceral fat area was significantly larger in the DISH group than in the non-DISH group (DISH group, 130.7 ± 58.2 cm2; Non-DISH group, 89.0 ± 48.1 cm2; p < 0.001). The prevalence of SEL was similar between the 2 groups (10.3% in the DISH group vs. 8.7% in the nonDISH group; p = 0.464). Poisson regression analysis revealed that the metabolic syndrome was significantly associated with DISH with odds ratio of 2.0 (95% confidence interval, 1.0-3.7; p = 0.004). CONCLUSION: Metabolic syndrome was significantly associated with DISH. Our data showed metabolic syndrome is potentially related to DISH.

When sizing the femoral component or determining its placement in total knee arthroplasty (TKA), if the anterior–posterior diameter of the femoral condyle is between component sizes, the selected size will differ depending on whether anterior referencing (AR) or posterior referencing (PR) is used. As a result, the amount of resected bone will also vary. In the present prospective study, we compared the two referencing methods to determine which is more suitable for individual patients. We recruited 58 patients (92 joints) who received TKA using the standard technique with intermediate-size components. AR was used in 26 joints, and PR in 23 joints. Seventeen of the patients underwent same-day bilateral TKA in which components of different sizes were used for the left and right joints. AR resulted in significantly smaller anterior and posterior offsets than PR. Preoperative clinical evaluation revealed no significant differences among cases in which intermediate-size components were indicated, or those in which components of different sizes were indicated. When an intermediate-sized component was indicated using the AR method, moving the sizer forward resulted in a larger posterior gap, but this technique was nevertheless considered acceptable. AR is likely to be more suitable than PR as it achieves more physiological anterior clearance.

STUDY DESIGN: Retrospective case series. OBJECTIVE: The aim of this study was to compare the utility and cost-effectiveness of multilevel lateral interbody fusion (LIF) combined with posterior spinal fusion (PSF) (L group) and conventional PSF (with transforaminal lumbar interbody fusion) (P group) in adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: The clinical and radiographic outcomes of multilevel LIF for ASD have been reported favorable; however, the cost benefit of LIF in conjunction with PSF is still controversial. METHODS: Retrospective comparisons of 88 surgically treated ASD patients with minimum 2-year follow-up from a multicenter database (L group [n = 39] and P group [n = 49]) were performed. Demographic and radiographic data, health-related quality of life (HRQoL), and the direct hospitalization cost for the initial surgery and 2-year total hospitalization cost were analyzed. RESULTS: Analyses of sagittal spinal alignment showed no significant difference between the two groups at baseline and 2 years post-operation. Surgical time was longer in the L group (L vs. P: 354 vs. 268 minutes, P < 0.01), whereas the amount of blood loss was greater in the P group (494 vs. 678 mL, P = 0.03). The HRQoL was improved similarly at 2 years post-operation (L vs. P: SRS-22 total score, 3.86 vs. 3.80, P = 0.54), with comparable revision rates (L vs. P: 18% vs. 10%, P = 0.29). The total direct cost of index surgery was significantly higher in the L group (65,937 vs. 49,849 USD, P < 0.01), which was mainly due to the operating room cost, including implant cost (54,466 vs. 41,328 USD, P < 0.01). In addition, the 2-year total hospitalization cost, including revision surgery, was also significantly higher in the L group (70,847 vs. 52,560 USD, P < 0.01). CONCLUSION: LIF with PSF is a similarly effective surgery for ASD when compared with conventional PSF. However, due to the significantly higher cost, additional studies on the cost-effectiveness of LIF in different ASD patient cohorts are warranted. LEVEL OF EVIDENCE: 3.

Patients with lumbar spinal canal stenosis (LSS) have impaired activities of daily living because of pain or motor paralysis, but no effective preventive treatment is currently available. The number of patients with LSS is predicted to continually increase as the average age of the global population increases. To provide a conceptual framework for improving healthy life expectancy, the Japanese Orthopaedic Association introduced the concept of locomotive syndrome, to which LSS is related. Ours and other studies have shown that LSS exacerbates locomotive syndrome and that surgical treatment is one method for improving it. Furthermore, we propose that the two-step test, a locomotive syndrome risk test, is effective for assessing the risk for falls and severity of LSS. Meanwhile, lumbar spinal epidural lipomatosis (LSEL), which is a manifestation of LSS, has been shown to be related to metabolic syndrome. Previous studies have suggested that the whole LSS can be also associated with metabolic syndrome. Although locomotive syndrome is very different from metabolic syndrome, which involves lipid metabolism, these two syndromes overlap, such as in LSS. Conducting research on LSS from the perspectives of both locomotive syndrome and metabolic syndrome may lead to novel methods for prevention and treatment of LSS and, conversely, may yield clues for resolving symptoms of the two syndromes. This review provides an overview of LSS from the perspective of locomotive syndrome and metabolic syndrome, along with findings from our research group.

Purpose: Many people with chronic musculoskeletal pain (CMP) seek healthcare from conventional and complementary and alternative medicine. However, treatment/therapy is not always adequate, patients often change healthcare providers, and some patients are left untreated. This study clarified care-seeking behaviours and explored factors behind the behaviours in people with CMP. Methods: Using a Japanese cross-sectional online survey, participants aged ≥ 20 years with non-cancer/fracture CMP lasting for ≥ 6 months and presenting ≤1 month, interfering with daily living activities and/or work were enrolled. We summarized and analysed the characteristics and factors associated with choice of healthcare providers; information on socio-demographics, including employment; ability to use healthcare, including income; and need for healthcare, including pain intensity, using a logistic regression model. Results: Among the 9105 respondents, 24.5% consulted physicians, 18.3% complementary and alternative medicine practitioners, and 57.2% were untreated. More respondents who had moderate-severe pain visited physician, more regularly employed and with high income visited complementary and alternative medicine, and less respondents who had moderate-severe pain were untreated. These were found to be associated with the respective healthcare use versus untreated. Conclusions: People with severe conditions, higher income and regular employment, and less severe conditions have visited physicians, complementary and alternative medicine practitioners and none, respectively. By applying this result at each type of healthcare provider, it may be possible to treat patients more appropriately.

STUDY DESIGN: Single-center retrospective study. PURPOSE: We aimed to explore the postoperative prognostic factors for spinal intramedullary ependymoma. OVERVIEW OF LITERATURE: Ependymoma (World Health Organization grade II) is the most frequent intramedullary spinal tumor and is treated by total resection. However, postoperative deterioration of motor function occasionally occurs. METHODS: Eighty patients who underwent surgical resection at Keio University and Fujita Health University in Tokyo, Japan between 2003 and 2015 with more than 2 years of follow-up were enrolled. A good surgical result was defined as an improvement in the modified McCormick Scale score by one grade or more or having the same clinical grade as was observed preoperatively. Meanwhile, a poor result was defined as a reduction in the McCormick Scale score of one grade or more or remaining in grade IV or V at final follow-up. Univariate and multivariate logistic regression analyses of the following factors were performed in the two groups: sex, age, preoperative Visual Analog Scale (VAS), tumor location, the extent of tumor resection, hemosiderin caps, cavity length, and tumor length on magnetic resonance imaging. RESULTS: At final follow-up, 15 patients were included in the poor results group and 65 in the good results group. In the univariate analysis, the factors related to poor results were as follows: higher age, preoperative McCormick Scale score severity, higher preoperative VAS, thoracic location, hemosiderin capped, and non-gross total resection (GTR). A multiple logistic regression analysis was conducted and showed that age, worse preoperative McCormick Scale score, and non-GTR were significant factors for poor prognosis. CONCLUSIONS: The independent risk factors for motor deterioration after ependymoma resection were age, worse preoperative McCormick Scale score, and non-GTR. Early surgery for patients with even mild neurological disorders could facilitate functional outcomes. These results may contribute to determining the optimal timing of surgery for spinal intramedullary ependymoma.

STUDY DESIGN: This was a case-control study. OBJECTIVE: The objective of this study was to clarify the surgical outcomes after cervical posterior decompression in patients who smoked. SUMMARY OF BACKGROUND DATA: Smoking is associated with poor outcomes in the field of spinal surgery. However, the impact of tobacco smoking on the outcomes after posterior decompression surgery has not been fully evaluated in patients with cervical spondylotic myelopathy. MATERIALS AND METHODS: In this retrospective multicenter study, 587 patients with cervical spondylotic myelopathy were enrolled at 17 institutions in Japan. Patients underwent cervical laminoplasty or laminectomy and were followed up for at least 1 year after surgery. Outcome measures were: preoperative smoking status, perioperative complications, the Japanese Orthopedic Association scale, and the Visual Analog Scale for neck pain. After adjusting for age and sex by exact matching, smoking and nonsmoking groups were compared using an unpaired t test for continuous variables or a χ test for categorical variables. RESULTS: There were 182 (31%) current smokers and 405 (69%) nonsmokers including previous smokers. After matching, 158 patients were extracted from each group. Demographic data and surgical information were almost the same between the groups. Regarding postoperative complications, there was no significant difference in the rate of surgical site infection, cerebrospinal fluid leakage, hematoma, segmental motor paralysis, or neurological deficit. However, smokers showed a significantly higher risk for delirium (3.8% vs. 0.0%, P=0.039). Smokers and nonsmokers showed comparable changes in functional recovery according to Japanese Orthopedic Association scores (3.2±2.1 vs. 3.0±2.1, P=0.425) and in neck pain reduction using the Visual Analog Scale (-1.7±3.1 vs. -1.4±2.8, P=0.417) at the final follow-up. CONCLUSIONS: Smokers exhibited functional restoration and neck pain reduction after cervical posterior decompression. Attention is required, however, for the postoperative complication of delirium, which could be caused by the acute cessation of tobacco smoking after admission. LEVEL OF EVIDENCE: Level III.

The degree of intervertebral disc (IVD) degeneration is qualitatively evaluated on T2-weighted imaging (T2WI). However, it is difficult to assess subtle changes in IVD degeneration using T2WI. Q-space imaging (QSI) is a quantitative diffusion-weighted imaging modality used to detect subtle changes in microenvironments. This study aimed to evaluate whether QSI can detect the inhibitory effects of the antioxidant N-acetylcysteine (NAC) in IVD degeneration. We classified female Wistar rats into control, puncture, and NAC groups (n = 5 per group). In the puncture and NAC groups, IVDs were punctured using a needle. The antioxidant NAC, which suppresses the progression of IVD degeneration, was orally administered in the NAC group 1 week prior to puncture. The progression and inhibitory effect of NAC in IVD degeneration were assessed using magnetic resonance imaging (MRI): IVD height, T2 mapping, apparent diffusion coefficient (ADC), and QSI. MRI was performed using a 7-Tesla system with a conventional probe (20 IVDs in each group). QSI parameters that were assessed included Kurtosis, the probability at zero displacement (ZDP), and full width at half maximum (FWHM). IVD degeneration by puncture was confirmed by histology, IVD height, T2 mapping, ADC, and all QSI parameters (P < .001); however, the inhibitory effect of NAC was confirmed only by QSI parameters (Kurtosis and ZDP: both P < .001; FWHM: P < .01). Kurtosis had the largest effect size (Kurtosis: 1.13, ZDP: 1.06, and FWHM: 1.02) when puncture and NAC groups were compared. QSI has a higher sensitivity than conventional quantitative methods for detecting the progressive change and inhibitory effect of NAC in IVD degeneration.

Chin on chest deformity caused by upper cervical kyphosis associated with ankylosing spondylitis is rare. A 66-year-old woman presented at our institute with chief complaints of difficulty in horizontal gaze and opening her mouth. Cervical radiographs showed a C0-2 angle of 1° on flexion and 7° on extension, and her chin-brow vertical angle was 49°. We planned fixation surgery at C0-5 posteriorly to prevent the progression of kyphosis, with slight correction of the kyphosis at C0-2. The correction was performed by pushing down the over lordotically contoured titanium rods connected to an occipital plate onto the C3-5 lateral mass screws, just like cantilever technique. No palpable cracking or loss of resistance was noticed during the correction. However, intraoperative radiographs revealed apparent anterior separation of the vertebral bodies between C3 and C4. Postoperative computed tomography images at the C3/4 level suggested hemorrhage from the fracture site. Tracheostomy was performed because of massive edema around the pharynx. To secure solid bone fusion, staged surgery to extend the fusion to T3 and to graft an additional iliac bone was performed. Fortunately, the C2-7 angle was corrected to 40°, and her chin-brow vertical angle was restored to 17° without any catastrophic complications. Although the patient finally obtained an ideal sagittal alignment, the surgeon should be aware that the technique had a higher perioperative risk for iatrogenic fracture, resulting in neurological and vascular injuries.

INTRODUCTION: Multiple spinal cord tumors rarely occur without genetic predisposition, and concurrent tumors with discrete pathologies developed at the same spinal level are most rare. Here, we report a case of concurrent dorsal schwannoma and ventral meningioma arising at the same upper cervical level (C1-C2). CASE PRESENTATION: A 55-year-old woman presented with neck pain and upper and lower extremity numbness for 1 year. Magnetic resonance imaging of the cervical spine showed a partially circumferential C-shaped intradural extramedullary tumor at C1-C2. The preoperative diagnosis based on imaging was intradural extramedullary meningioma with circumferential development. Surgical resection was performed, and dorsal subpial and ventral tumors were detected. Intraoperative pathological diagnosis was schwannoma for the dorsal tumor and meningioma for the ventral tumor. Both tumors were completely resected, followed by circumferential durotomy and duroplasty (Simpson grade 1 resection). Although symptoms related to cerebrospinal fluid hypovolemia occurred immediately after surgery, they disappeared within several days. At 2 years postoperatively, no local recurrence has been identified with mild kyphotic cervical malalignment. DISCUSSIONS: Only nine cases of concurrent multiple spinal tumors with discrete histopathological types at the same cervical level have been reported to date, however, this is the first case of meningioma combined with subpial schwannoma. Furthermore, although the ventral location of meningioma often compelled inadequate resection leaving behind a dura mater from which meningioma originated, a gross total resection including dura mater was achieved accompanied with circumferential duroplasty. Careful and sequential postoperative follow-up is ongoing for this individual.

STUDY DESIGN: Case-control study. OBJECTIVE: To examine factors influencing cervical alignment after corrective surgery for adult patients with adolescent idiopathic scoliosis (AdIS) SUMMARY OF BACKGROUND DATA.: Corrective surgery for spinal deformity influences postoperative cervical spinal alignment, but changes in the cervical alignment in adults with AdIS are scarcely reported. METHODS: We retrospectively examined 85 patients with AdIS who underwent posterior corrective surgery for thoracic or lumbar major curve and were followed up for 2 years. Clinical characteristics, radiographic parameters, and health-related quality of life (HRQOL) were evaluated. Cervical deformity (CD) was defined as one of the following cases: (1) T1 tilt minus C2-C7 angle more than 20°, (2) C2-C7 SVA more than 40 mm, (3) and C2-C7 angle less than -10°. Patients were divided into those with and without CD based on the defined criteria; statistically relevant factors were analyzed. RESULTS: There were 19 patients in the postoperative CD group. The average age at the time of surgery was lower in the CD group (26.5 vs. 31.4). In the CD group, the average preoperative T1 tilt was smaller (1.1° vs. 12.5°), and the C2-C7 angle was kyphotic (-16.1° vs. 3.0°). The average kyphotic angle at thoracic spine (T5-T12) was lower in the CD group preoperatively (12.5° vs. 19.5°) and postoperatively (15.2° vs. 20.8°). HRQOL outcomes were comparable between the groups. Of the patients with preoperative CD, 51.5% (n = 17) maintained their deformity at the final follow-up, and baseline C2-C7 angle was lower than those who converted to non-CD following surgery (n = 16) (-17.0° vs. -10.3°). CONCLUSION: More than half of the patients with baseline CD maintained their cervical malalignment postoperatively. Patients with postoperative CD presented cervical kyphotic and thoracic hypokyphotic alignments before surgery. Because CD has the potential to lead to cervical degeneration, careful follow-up observation is necessary for these young patients. LEVEL OF EVIDENCE: 3.

Mechanical failure (MF) following adult spinal deformity (ASD) surgery is a severe complication and often requires revision surgery. Predicting a patient's risk of MF is difficult, despite several potential risk factors that have been reported. The purpose of this study was to establish risk stratification model for predicting the MF based on demographic, and radiographic data. This is a multicenter retrospective review of the risk stratification for MF and included 321 surgically treated ASD patients (55 ± 19 yr, female: 91%). The analyzed variables were recorded for at least 2 yr and included age, gender, BMI, BMD, smoking status, frailty, fusion level, revision surgery, PSO, LIF, previous surgery, spinal alignment, GAP score, Schwab-SRS type, and rod materials. Multivariate logistic regression analyses were performed to identify the independent risk factors for MF. Each risk factor was assigned a value based on its regression coefficient, and the values of all risk factors were summed to obtain the PRISM score (range 0-12). We used an 8:2 ratio to split the data into a training and a testing cohort to establish and validate the model. MF developed in 41% (n = 104) of the training subjects. Multivariate analysis revealed that BMI, BMD, PT, and frailty were independent risk factors for MF (BMI: OR 1.7 [1.0-2.9], BMD: OR 3.8 [1.9-7.7], PT: OR 2.6 [1.8-3.9], frailty: OR 1.9 [1.1-3.2]). The MF rate increased with and correlated well with the risk grade as shown by ROC curve (AUC of 0.81 [95% CI 0.76-0.86]). The discriminative ability of the score in the testing cohort was also good (AUC of 0.86 ([95% CI 0.77-0.95]). We successfully developed an MF-predicting model from individual baseline parameters. This model can predict a patient's risk of MF and will help surgeons adjust treatment strategies to mitigate the risk of MF.

INTRODUCTION: Spinal intramedullary endodermal cyst is a rare spinal cord tumour. In particular, an endodermal cyst that includes glial tissues is extremely rare. Herein, we present the case of an individual with a thoracic spinal cord intramedullary endodermal cyst, which includes glial tissues that achieved gross total resection by surgery. CASE PRESENTATION: A 59-year-old man presented with a 10-month history of right thigh pain and numbness. Magnetic resonance imaging (MRI) revealed a well-marginated 15-mm cystic lesion at the T7-T8 level. We performed cystectomy and achieved gross total resection. Pathological findings revealed an endodermal cyst, with the presence of glial tissues. No recurrence of cysts was observed upon MRI 2 years after the surgery. DISCUSSION: Endodermal cyst is defined by pathological findings of a cyst lined by columnar epithelium of presumed endodermal derivation. To date, only 104 reported cases of intramedullary endodermal cysts have been reported; our report was the third case that showed the presence of glial cells in the cyst during pathological examination. Intramedullary cysts are generally difficult to completely resect, with many recurrences. Although we achieved gross total resection, careful follow-up is necessary in the future.