藤田 順之

STUDY DESIGN: Retrospective study. OBJECTIVE: To compare outcomes for plate fixation versus suture suspension in expansive open-door laminoplasty (ELAP) for cervical spondylotic myelopathy (CSM). SUMMARY OF BACKGROUND DATA: C5 palsy and laminar closure have been reported to occur after ELAP when suture suspension is used to anchor the opened lamina. MATERIALS AND METHODS: We assessed 174 patients with CSM who were treated by ELAP using either suture suspension (114 patients, mean age 63.3 y, 83 men and 31 women, mean follow-up 12.0 mo) or laminoplasty plate (60 patients, mean age 65.6 y, 45 men and 15 women, mean follow-up 12.6 mo) to maintain the position of the opened laminae. We compared clinical outcomes, radiographic findings, and complications between the 2 groups. RESULTS: Mean Japanese Orthopaedic Association scores had improved significantly for both groups at the final follow-up (P<0.001), with similar recovery rates: scores improved from 10.8±2.8 to 13.4±2.8 points in the suture-suspension (SS) group and from 11.3±2.7 to 13.6±2.2 points in the laminoplasty plate (LP) group. The incidence of C5 palsy was significantly higher in the SS group (7.9%) than in the LP group (1.7%; P<0.05). Computed tomography (CT) showed larger mean angles of the opened laminae in the SS group compared with the LP group (P<0.01). Magnetic resonance imaging (MRI) showed that the mean anterior spinal-cord space at the C5 level was larger in the SS group than in the LP group (P<0.01). CONCLUSIONS: Plate fixation in ELAP produced comparable clinical outcomes and significantly lowered the incidence of C5 palsy compared with suture suspension. CT and MRI findings indicated that laminoplasty plate fixation prevented excessive opening of the lamina and decreased dorsal spinal-cord shift, which might explain the lower incidence of C5 palsy.

STUDY DESIGN: A multicenter retrospective case series of patients treated surgically for adult spinal deformity (ASD). OBJECTIVE: The aim of this study was to compare clinical outcomes between propensity score matched ASD patients with or without drop body syndrome (DBS). SUMMARY OF BACKGROUND DATA: DBS is an extreme primary sagittal-plane deformity often seen in Asian countries. Although the importance of sagittal alignment is widely recognized, surgical outcomes for deformities purely in the sagittal plane are poorly understood. METHODS: This study included 243 consecutive patients (age 66 ± 17 years; range 22-78) who were treated surgically for ASD and were followed at least 2 years (mean follow-up 3.7 ± 2.3 years). DBS was defined as a primary lumbar kyphosis with PI-LL >40°, Cobb angle <30°, and multifidus cross-sectional area <300 mm. DBS patients were matched with non-DBS patients by propensity scores for age, gender, lowest instrumented vertebra (LIV) level, and number of levels fused. Demographics, radiographic findings, and clinical outcomes were compared between DBS and non-DBS patients. RESULTS: Of 243 patients with ASD, 34 had DBS (14%); 28 of these were propensity-matched with ASD patients without DBS. Baseline bone mineral density (BMD), body mass index (BMI), and frailty were similar in DBS and non-DBS patients. Baseline sagittal alignment was worse in DBS than in non-DBS patients [C7SVA 14 ± 5 vs. 8 ± 5 cm; pelvic incidence (PI) - lumbar lordosis (LL) 60 ± 14 vs. 36 ± 20°], and scoliosis research society (SRS)22 scores were also worse for DBS patients (2.5 ± 0.6 vs. 2.9 ± 0.8). Although DBS patients had more complications (20 DBS vs. 16 non-DBS), the clinical outcomes were similarly improved in both groups after surgery. At the 2-year follow-up, the spinopelvic malalignment was worse in DBS than non-DBS patients (PI-LL 17 ± 16° vs. 8 ± 13°, P < 0.05). CONCLUSION: DBS affected 14% of 234 ASD patients. Although DBS patients had inferior baseline SRS22 scores than non-DBS patients, ASD surgery resulted in similar clinical improvement in both groups. Future studies should examine the influence of lifestyle and genetics on clinical outcomes after surgery for DBS. LEVEL OF EVIDENCE: 3.

OBJECTIVE: Intramedullary cavernous hemangioma (CH) is a rare vascular lesion that is mainly characterized by the sudden onset of hemorrhage in young, asymptomatic patients, who then experience serious neurological deterioration. Despite the severity of this condition, the therapeutic approach and timing of intervention for CH remain matters of debate. The aim of this study was to evaluate the clinical characteristics of CH patients before and after surgery and to identify prognostic indicators that affect neurological function in these patients. METHODS: This single-center retrospective study included 66 patients who were treated for intramedullary CH. Among them, 57 underwent surgery and 9 patients received conservative treatment. The authors collected demographic, symptomology, imaging, neurological, and surgical data. Univariate and multivariate logistic regression analyses were performed to identify the prognostic indicators for neurological function. RESULTS: When comparing patients with stable and unstable gait prior to surgery, patients with unstable gait had a higher frequency of hemorrhagic episodes (52.4% vs 19.4%, p = 0.010), as assessed by the modified McCormick Scale. The lesion was significantly smaller in patients who underwent conservative treatment compared with surgery (2.5 ± 1.5 mm vs 5.9 ± 4.1 mm, respectively; p = 0.024). Overall, the patients experienced significant neurological recovery after surgery, but a worse preoperative neurological status was identified as an indicator affecting surgical outcomes by multivariate analysis (OR 10.77, 95% CI 2.88–40.36, p < 0.001). In addition, a larger lesion size was significantly associated with poor functional recovery in patients who had an unstable gait prior to surgery (8.6 ± 4.5 mm vs 3.5 ± 1.6 mm, p = 0.011). CONCLUSIONS: Once a hemorrhage occurs, surgical intervention should be considered to avoid recurrence of the bleeding and further neurological injury. In contrast, if the patients with larger lesion presented with worse preoperative functional status, surgical intervention could have a risk for aggravating the functional deficiencies by damaging the thinning cord parenchyma. Conservative treatment may be selected if the lesion is small, but regular neurological examination by MRI is needed for assessment of a change in lesion size and for detection of functional deterioration. ABBREVIATIONS: AIS = ASIA Impairment Scale; ASIA = American Spinal Injury Association; CH = cavernous hemangioma; EBL = estimated blood loss; JOA = Japanese Orthopaedic Association; mMS = modified McCormick Scale.

Intervertebral discs (IVDs) are avascular; however, ingrowth of blood vessels into their outer regions has been noted during the progression of degeneration. The mechanisms underlying vascularization in IVD degeneration are not completely understood. Semaphorin 3A (Sema3A), originally characterized as a chemorepulsive factor for growing axons in the developing nervous system, inhibits angiogenesis. This study aimed to elucidate the potential involvement of Sema3A in maintaining tissue homeostasis within the avascular IVD. We demonstrated that the mRNA expression of Sema3A was higher in rat annulus fibrosus (AF) than in nucleus pulposus (NP) and that its expression level decreased with age. Both mRNA and protein expression level of Sema3A was also markedly suppressed in AF tissues of a rat IVD degeneration model. Both real-time RT-PCR and Western blot clearly indicated that Sema3A expression significantly reduced by treating inflammatory cytokines in rat AF cells. In a gain- and loss-of-function study, we observed that Sema3A reduced the catabolic shift in rat AF cells. In addition, our results indicated that Sema3A potentially inhibited the IL-6/JAK/STAT pathway. Finally, BrdU assay and tube formation assay revealed that treatment of recombinant Sema3A significantly blocks both proliferation and tube formation of HUVEC. Our results indicate that Sema3A may help maintain IVD tissue homeostasis. Thus, although further studies are needed, Sema3A may be a potential molecular target for suppressing IVD degeneration. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

BACKGROUND CONTEXT: Spinal epidural lipomatosis (SEL) is a condition in which excess lumbar epidural fat (EF) deposition often leads to compression of the cauda equina or nerve root. Although SEL is often observed in obese adults, no systematic research investigating the potential association between SEL and metabolic syndrome has been conducted. PURPOSE: To elucidate potential association between SEL and metabolic syndrome. STUDY DESIGN: An observational study used data of a medical checkup. PATIENT SAMPLE: We retrospectively reviewed data from consecutive subjects undergoing medical checkups. A total of 324 subjects (174 men and 150 women) were enrolled in this study. OUTCOME MEASURES: The correlation of EF accumulation with demographic data and metabolic-related factors was evaluated. METHODS: The degree of EF accumulation was evaluated based on the axial views of lumbar magnetic resonance imaging. Visceral and subcutaneous fat areas were measured at the navel level using abdominal computed tomography. Metabolic syndrome was diagnosed according to the criteria of the Japanese Society of Internal Medicine. The correlation of SEL with metabolic syndrome and metabolic-related conditions was statistically evaluated. RESULTS: The degree of EF accumulation demonstrated a significant correlation to body mass index, abdominal circumference, and visceral fat area. However, age, body fat percentage, and subcutaneous fat area showed no correlation with the degree of EF accumulation. Logistic regression analysis revealed that metabolic syndrome (odds ratio [OR]=3.8, 95% confidence interval [CI]=1.5-9.6) was significantly associated with SEL. Among the diagnostic criteria for metabolic syndrome, visceral fat area ≥100 cm2 (OR=4.8, 95% CI=1.5-15.3) and hypertension (OR=3.5, 95% CI=1.1-11.8) were observed to be independently associated with SEL. CONCLUSION: This is the first study to demonstrate that metabolic syndrome is associated with SEL in a relatively large, unbiased population. Our data suggest that metabolic-related conditions are potentially related to EF deposition and that SEL could be a previously unrecognized manifestation of metabolic syndrome.

PURPOSE: To clarify the effect of posterior correction and fusion surgery on the trunk-pelvic kinematics during gait in adolescent idiopathic scoliosis (AIS) patients with single thoracic major curve. METHODS: Among preoperative AIS patients who planned correction surgery, 18 patients with Lenke type 1A or B were selected for this study. All patients were female. The patients' trunk and pelvic kinematics during gait were measured three-dimensionally and dynamically using reflective markers, optoelectronic motion capture system. The gait analysis was performed before and 1-2 years after surgery. The trunk and pelvic symmetry during gait was evaluated at coronal, sagittal, and transverse planes between concave and convex sides. RESULTS: The trunk and pelvic angles in sagittal and coronal planes were equivalent between concave and convex sides before and after surgery. Preoperatively, transverse trunk rotation angles were significantly deviated toward the concave (left) side during both static standing (4.3 ± 2.0°) and gait (8.8 ± 0.6°, p < 0.01). Preoperative transverse pelvic rotation angles were significantly deviated toward the convex side during static standing (4.0 ± 3.8°). However, pelvis displayed with symmetric rotational kinematics during gait. Postoperatively, the deviated transverse trunk rotation angle significantly decreased (1.6 ± 0.3°), and the transverse rotational kinematics of both trunk and pelvis improved to symmetric. CONCLUSIONS: Posterior correction and fusion surgery have improved preoperative asymmetric global rotational kinematics of trunk and pelvis in transverse plane to symmetric postoperatively in AIS patients with thoracic single major curve. These slides can be retrieved under Electronic Supplementary Material.

STUDY DESIGN: Retrospective multicenter study. OBJECTIVES: To evaluate the outcomes of posterior cervical decompression for cervical spondylotic myelopathy (CSM) when performed by board-certified spine (BCS) or non-BCS (NBCS) surgeons. METHODS: We reviewed outcomes for 675 patients who underwent surgery for CSM, were followed at least 1 year after surgery, and were assessed preoperatively and at final follow-up by Japanese Orthopaedic Association (JOA) scores and by the visual analog scale (VAS) for the neck. Cervical alignment was assessed on radiographs by C2-C7 angles, and range of motion (ROM) by extension minus flexion C2-C7 angles. We compared outcomes for BCS surgeons, who must meet several requirements, including experience in more than 300 spinal surgeries, and for NBCS surgeons. RESULTS: BCS surgeons performed 432 of 675 laminoplasties. NBCS surgeons were primary in 243 surgeries, of which 187 were directly supervised by a BCS surgeon. BCS surgeons required significantly less time in surgery (98.0 ± 39.5 vs 108.1 ± 49.7 min; P < .01). BCS and NBCS surgeons had comparable perioperative complications rates, and preoperative-to-postoperative changes in JOA scores (2.9 ± 2.1 vs 3.1 ± 2.3; P = .40) and VAS (-1.5 ± 2.9 vs -1.4 ± 2.5; P = .96). Lordotic cervical alignment and ROM were maintained after operations by both groups. CONCLUSIONS: Surgical outcomes such as functional recovery, complication rates, and cervical dynamics were comparable between the BCS and NBCS groups. Thus, posterior cervical decompression for CSM is safe and effective when performed by junior surgeons who have been trained and supervised by experienced spine surgeons.

BACKGROUND: Locomotive syndrome is a condition in which the ability to lead a normal life is restricted owing to a dysfunction in one or more of the parts of the musculoskeletal system. Although lumbar spinal canal stenosis (LSS) is considered to cause locomotive syndrome, a detailed assessment of the association between two pathologies has not yet been reported. METHODS: The clinical data of patients aged > 65 years old who planned to undergo surgery for LSS at multiple institutions were prospectively collected from April 2016 to August 2017. A total of 200 participants comprising 120 men and 80 women were enrolled in this study. Association of severity of LSS evaluated by Zurich Claudication Questionnaire scores with three locomotive syndrome risk tests (Stand-up Test, the Two-step Test, and a 25-question risk assessment) and Timed Up-and-Go Test were evaluated. RESULTS: In the total assessment of locomotive syndrome, 96.5% of the participants were diagnosed as grade 2, and the remaining 3.5% were diagnosed as grade 1. When the participants were divided into 3 groups according to the LSS severity, the scores of all locomotive syndrome risk tests were significantly worse with increasing LSS severity. Logistic regression analysis revealed that LSS severity was positively correlated with the risk level of locomotive syndrome evaluated by the Two-step Test (OR = 3.45, CI = 1.33-8.96). CONCLUSIONS: All LSS patients with surgical indications were diagnosed as having locomotive syndrome. In addition, our results indicated that LSS severity is potentially associated with the progression of locomotive syndrome. The treatment of LSS may be beneficial in alleviating the risk for locomotive syndrome.

PURPOSE: Potential associations between radiographic parameters and the incidence of symptomatic postoperative spinal epidural hematoma (PSEH) have not been identified. This study aimed to identify risk factors including radiographic parameters for symptomatic PSEH after posterior decompression surgery for lumbar spinal canal stenosis (LSS). METHODS: We retrospectively reviewed 1007 consecutive patients who underwent lumbar decompression surgery for lumbar spinal canal stenosis (LSS) at our institution. We identified 35 cases of symptomatic PSEH, defined by clinical symptoms and MRI findings, and selected 3 or 4 age- and sex-matched control subjects for each PSEH subject (124 controls). We compared radiographic parameters and previously reported risk factors between PSEH and control subjects. RESULTS: Compared to the control group, PSEH patients had significantly higher preoperative systolic (p = .020) and diastolic (p = .048) blood pressure, and more levels of decompression (p = .001). PSEH and control subjects had significant differences in lumbar lordosis (PSEH 24.8° ± 14.6°, control 34.8° ± 14.5°), pelvic tilt (25.1° ± 11.7° vs. 20.8° ± 8.4°), sacral slope (23.4° ± 9.4° vs. 27.6° ± 8.3°), and pelvic incidence minus lumbar lordosis (23.7° ± 15.0° vs. 13.7° ± 14.6°). Multivariate analysis revealed two significant risk factors for PSEH: decompression of two or more levels and lumbar lordosis < 25°. CONCLUSIONS: Multilevel decompression and hypolordosis are significant risk factors for symptomatic PSEH after decompression surgery for LSS. LSS patients with lumbar hypolordosis or multilevel stenosis should be carefully observed for PSEH after decompression surgery. These slides can be retrieved under Electronic Supplementary Material.

PURPOSE: ASD surgery improves a patient's health-related quality of life, but it has a high complication rate. The aim of this study was to create a predictive model for complications after surgical treatment for adult spinal deformity (ASD), using spinal alignment, demographic data, and surgical invasiveness. METHODS: This study included 195 surgically treated ASD patients who were > 50 years old and had 2-year follow-up from multicenter database. Variables which included age, gender, BMI, BMD, frailty, fusion level, UIV and LIV, primary or revision surgery, pedicle subtraction osteotomy, spinal alignment, Schwab-SRS type, surgical time, and blood loss were recorded and analyzed at least 2 years after surgery. Decision-making trees for 2-year postoperative complications were constructed and validated by a 7:3 data split for training and testing. External validation was performed for 25 ASD patients who had surgery at a different hospital. RESULTS: Complications developed in 48% of the training samples. Almost half of the complications developed in late post-op period, and implant-related complications were the most common complication at 2 years after surgery. Univariate analyses showed that BMD, frailty, PSO, LIV, PI-LL, and EBL were risk factors for complications. Multivariate analysis showed that low BMD, PI-LL > 30°, and frailty were independent risk factors for complications. In the testing samples, our predictive model was 92% accurate with an area under the receiver operating characteristic curve of 0.963 and 84% accurate in the external validation. CONCLUSION: A successful model was developed for predicting surgical complications. Our model could inform physicians about the risk of complications in ASD patients in the 2-year postoperative period. These slides can be retrieved under Electronic Supplementary Material.

CASE: A 74-year-old woman presented with severe trunk deformity. Radiographs revealed severe sagittal and coronal imbalance with spinal canal stenosis at L4 to L5. Anterior cages were placed at L2 to L3, L3 to L4, and L4 to L5. Three days later, posterior correction surgery from T5 to the ilium with decompression at L4 to L5 was performed. At 30 minutes after surgery, leg muscle strength severely deteriorated. Emergency surgery revealed disc fragments protruding into the spinal canal at L2 to L3. CONCLUSION: Because posteriorly placed extreme lateral interbody fusion (XLIF) cages can be a risk factor for disc protrusion into the spinal canal, computed tomographic evaluation or prophylactic posterior decompression should be considered before the correction procedure.

PURPOSE: To validate the effectiveness of percutaneous pedicle screw (PPS) fixation for spinal fractures associated with diffuse idiopathic skeletal hyperostosis (DISH) by comparing surgical outcomes for PPS fixation and conventional open posterior fixation. Patients with DISH are vulnerable to unstable spinal fractures caused by trivial trauma, and these fractures have high rates of delayed paralysis, postoperative complications, and mortality. METHODS: This retrospective study assessed surgical outcomes for 16 patients with DISH (12 men; mean age 76.1 ± 9.4 years) who underwent PPS fixation for spinal fractures (pedicle screw (PS) group), and for a control group of 25 patients with DISH (18 men; mean age 77.9 ± 9.9 years) who underwent conventional open fixation (O group) at our affiliated hospitals from 2007 to 2017. We evaluated the preoperative physical condition (American Society of Anesthesiologists (ASA) classification), neurological status (Frankel grade), and improvement after surgery, fusion length, operating time, estimated blood loss, and perioperative complications. RESULTS: Preoperatively, the PS group consisted of one ASA-1 patient, eight ASA-2 patients, six ASA-3 patients, and one ASA-4 patient; by Frankel grade, there were 2 grade B patients, 13 grade C, 4 grade D, and 6 grade E patients. The O group had 2 ASA-1 patients, 13 ASA-2, 9 ASA-3, and 1 ASA-4 patients. Frankel grades in the O group reflected severe neurological deficits, with 3 grade C patients, 2 grade D, and 11 grade E ( p = 0.032) patients. The two groups had similar rates of neurological improvement (33.3% of PS and 40.0% of O patients; p = 0.410) and mean fusion length (PS 5.1 ± 0.8 segments; O 4.9 ± 1.2). The mean operating time and estimated blood loss were 168.1 ± 46.7 min and 133.9 ± 116.5 g, respectively, in the PS group, and 224.6 ± 49.8 min and 499.9 ± 368.5 g in the O group. Three O-group patients died of hypovolemic shock, respiratory failure, and pneumonia, respectively, within a year of surgery. CONCLUSION: Conventional open posterior fixation and PPS fixation for DISH-related spinal fractures were similar in fusion length and neurological improvement. However, PPS fixation was less invasive and had lower complication rates.

INTRODUCTION: Tenosynovial giant cell tumors (TSGCTs) generally occur in the limb joints, and only rarely in the spine. This case report describes a patient with TSGCT of the spine at C1-C2, which was treated surgically and diagnosed as TSGCT. CASE PRESENTATION: A 32-year-old woman with a 4-month history of neck pain and numbness in both upper extremities was referred to our department. Magnetic resonance imaging (MRI) revealed a neoplastic lesion extending from the left epidural space to the erector spinae muscles at the C1-C2 vertebral level, which was isointense on T1-weighted images, heterogeneously hypointense on T2-weighted images, and showed heterogeneous enhancement on gadopentetate dimeglumine (Gd-DTPA)-enhanced T1-weighted images. Computed tomography showed no findings suggestive of bone destruction of the vertebral body. Because the neurological symptoms were progressive, total macroscopic resection of the tumor was performed via a posterior approach. Histopathological examination of the resected specimen revealed the diagnosis of TSGCT. Improvement of the both the neck pain and upper-extremity numbness was noted postoperatively. An MRI obtained 6 months after the surgery revealed no evidence of tumor recurrence and the postoperative course was uneventful. DISCUSSION: TSGCT of the upper cervical spine (C1-C2) is rare, and this is the tenth reported case. If a tumor is heterogeneously hypointense on T2-weighted MRI, which reflects hemosiderosis, the possibility of this tumor should be considered in the differential diagnosis.

STUDY DESIGN: Retrospective multicenter study. OBJECTIVE: We aimed to assess the outcomes following posterior cervical decompression for cervical spondylotic myelopathy (CSM) in a large sample of patients older than 80 years. SUMMARY OF BACKGROUND DATA: Although age is a predictor of surgical outcomes for CSM, most previous studies have only investigated the effect of age for patients aged 65 to 75 years, and surgical outcomes remain unclear for older patients. METHODS: Patients older than 50 years who underwent posterior cervical decompression for CSM were enrolled from 17 institutions. The patients were grouped into a young-old group (<80 yrs old) and an old-old group (≥80 yrs). Clinical information, comorbidities, perioperative complications, Japanese Orthopaedic Association (JOA) scores, Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), visual analog scale (VAS) scores, and radiographic parameters were compared between the two groups. All patients were followed for at least 1 year after surgery. RESULTS: The young-old and old-old groups included 491 and 77 patients, respectively. The JOA score and quality of life measured by JOACMEQ improved significantly after surgery in both groups. Compared with the young-old group, the old-old group had lower preoperative JOA scores (9.6 vs. 11.0), lower final JOA scores (12.6 vs. 14.0), and lower recovery rates (42% vs. 50%). However, there were no significant differences in perioperative complications or in the VAS scores at the final assessments. The old-old group had a higher mean preoperative sagittal Cobb angle at C2-C5, though this was not statistically significant postoperatively. CONCLUSION: Posterior decompression surgery is safe and beneficial for patients older than 80 years with CSM, despite having a more limited neurological recovery compared with younger patients. LEVEL OF EVIDENCE: 3.

STUDY DESIGN: A retrospective study. OBJECTIVE: To identify the radiographic differences between Chinese and Japanese patients with cervical ossification of the posterior longitudinal ligament (OPLL) using computed tomography (CT) and magnetic resonance imaging (MRI), and to compare the characteristics of OPLL between the two nationalities. SUMMARY OF BACKGROUND DATA: OPLL has a high prevalence in East Asia. However, the differences between Chinese and Japanese OPLL patients are poorly known. METHODS: This was a retrospective study of Chinese (n = 300) and Japanese (n = 102) consecutive patients who received a diagnosis of cervical OPLL between January 2010 and December 2014. All patients underwent CT and MRI. The type and distribution of OPLL were determined. Spinal compression was assessed by MRI. OPLL type, distribution, comorbidity, and compression of the spinal cord were examined. The ossification index (OP-index) was used to evaluate the OPLL. Factors contributing to the OP-index were examined by multivariate analysis. RESULTS: The Chinese patients were younger than the Japanese patients (P < 0.0001), and there were more women among the Chinese patients (P = 0.0002). The OP-index was higher among the Japanese patients (median, 5 vs. 4, P = 0.003). Among men, OPLL lesions were more frequent in the under 55-year-old Japanese at C7 (P = 0.04), in the 55 to 64-year-old Japanese at C4, C5, and C6 (all P < 0.05), and in the over 64-year-old Japanese at C3/4 (P = 0.01), compared with their Chinese counterparts. Among women, OPLL lesions were more frequent in the 55 to 64-year-old Japanese at C6 (P = 0.04). The multivariate analysis showed that only age was independently associated with the OP-index (odds ratio [OR] = 1.023, 95% confidence interval [CI]: 1.002-1.045, P = 0.034). CONCLUSION: Japanese patients had a higher frequency of OPLL lesions at C5, C6, and C7. Age was independently associated with OPLL. LEVEL OF EVIDENCE: 3.

STUDY DESIGN: A 20-year longitudinal study. OBJECTIVE: To evaluate the long-term effect of sagittal alignment of the cervical spine on intervertebral disk degeneration in healthy asymptomatic subjects. SUMMARY OF BACKGROUND DATA: This study continues a previous 10-year longitudinal study to determine whether sagittal alignment affects disk degeneration during normal aging. MATERIALS AND METHODS: We assessed 90 healthy subjects (30 men and 60 women) from among 497 volunteers who underwent magnetic resonance imaging (MRI) and plain radiographs of the cervical spine between 1994 and 1996 (follow-up rate 18.1%). The mean age at the initial study was 35.5±13.4 years (11-65 y). We compared initial MRIs and follow-up MRIs, conducted at an average of 21.6 years after the initial study, for (1) decreased signal intensity of the intervertebral disks, (2) posterior disk protrusion, and (3) disk-space narrowing from C2-3 to C7-T1. Subjects were grouped by age at follow-up (under 40 vs. 40 y and older) and by a lordotic or nonlordotic cervical sagittal alignment at baseline. We assessed neck pain, stiff shoulders, and upper-arm numbness at follow-up, and examined associations between clinical symptoms and MRI parameters. RESULTS: Progressive changes during the 20-year period included a decrease in disk signal intensity (84.4% of subjects), posterior disk protrusion (86.7%), and disk-space narrowing (17.8%). No significant association was observed between sagittal alignment and decreased disk signal intensity, posterior disk protrusion, or disk-space narrowing. Among subjects over the age of 40, progressive degenerative changes at C7-T1 were significantly more frequent in nonlordotic subjects (90.9%) compared with those with cervical lordosis (54.2%, P=0.032). The prevalence of clinical symptoms was similar in lordotic and nonlordotic subjects at follow-up. CONCLUSIONS: Nonlordotic cervical alignment was related to the progression of disk degeneration at C7-T1 but not other levels. Cervical alignment did not affect the development of clinical symptoms in healthy subjects. LEVEL OF EVIDENCE: Level III.

BACKGROUND: Metabolomics is one of the "omics" technologies, and is a comprehensive analysis of small molecule metabolites which include amino acid, nucleotides, carbohydrates and fatty acid. The purpose of the present study was to compare the differences of metabolite profiling between patients with ossification of the posterior longitudinal ligament (OPLL) and control subjects. METHODS: We analyzed plasma metabolites in patients with cervical OPLL (n = 10) and in control subjects (n = 10). Ionic metabolites were analyzed using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS) and lipophilic metabolites were analyzed using liquid chromatograph time-of-flight mass spectrometry (LC-TOFMS). RESULTS: A total of 259 metabolites (144 metabolites in CE-TOFMS and 115 metabolites in LC-TOFMS) were detected. Among the 259 metabolites, six metabolites, namely acylcarnitine (AC) (14:0), palmitoylcarnitine, AC (18:2), fatty acid (FA) (24:2), thyroxine, thiaproline were significantly larger in OPLL group, even in analyzes excluding patients with diabetes mellitus and hyperlipidemia. CONCLUSIONS: We examined the metabolite profiling in patients with OPLL for the first time and detected six metabolites showing suggestive association with disease. These results of the present study could lead to new insights into clarifying the molecular pathomechanisms of OPLL.

INTRODUCTION: Intramedullary lesions and tumors are generally accessed by a posterior approach. However, if the lesion is located on the ventral side of the spinal cord, a posterior resection with myelotomy poses technical difficulties. We report two cases of complete resection of a cervical ventral intramedullary cavernous hemangioma using an anterior approach. CASE REPORT: Two cases of intramedullary cavernous hemangioma located on the ventral side of the spinal cord were successfully treated by total resection with anterior cervical corpectomy followed by anterior spinal fusion with an autologous bone strut from the iliac crest. In both cases, the postoperative course was uneventful, and there was no neurological deficit. Bony fusion was achieved, and there was no recurrence or complication during a follow-up period of at least two years. CONCLUSIONS: Here, we describe an anterior approach for total resection of cavernous hemangiomas on the ventral side of the cervical spinal cord. Outcomes were stable two years after the operations. Although the method should be assessed with more patients and a longer follow-up time, this anterior approach may be useful for the radical resection of a vascular malformation or tumor.

STUDY DESIGN: Retrospective review of surgically treated 481 adult patients with spinal disorders. OBJECTIVE: The aim of this study was to elucidate the effect of frailty and comorbidities on postoperative health-related quality of life (HRQoL) and complication rates. SUMMARY OF BACKGROUND DATA: Elective surgeries for spinal disorders not only improve clinical outcomes but also have high complication rates. METHODS: We retrospectively reviewed the results of consecutive elective spine surgeries for 156 adult spinal deformities (ASDs: 65 ± 9 years), 152 degenerative spondylolisthesis (DS: 64 ± 10 years), or 173 lumbar spinal canal stenosis (LSCS: 71 ± 9 years) with follow-up of at least 2 years. Modified Frailty Index (mFI) and Charlson Comorbidity Index (CCI) were determined from baseline demographics. We compared the prevalence and the influence of mFI and CCI on postoperative outcomes and complication rates. RESULTS: The mFI and CCI were significantly worse in ASD than in others (mFI: ASD 0.09 ± 0.12, DS 0.06 ± 0.06, LSCS 0.04 ± 0.05, P < 0.01. CCI: ASD 2.1 ± 1.6, DS 1.4 ± 0.7, LSCS 1.6 ± 0.9, P < 0.01). Postoperative HRQoL deteriorated as mFI worsened in ASD (nofrail: Oswestry Disability Index [ODI] 26 ± 11, Scoliosis Research Society Questionnaire [SRS] 3.7 ± 0.7; prefrail: ODI 32 ± 12, SRS 3.6 ± 0.6; frail: ODI 42 ± 15, SRS 3.2 ± 0.7). In DS and LSCS, however, SF-36 physical component score and mental component score improved regardless of mFI and CCI. The 2-year major complications rate increased with frailty (36%, 58%, and 81%) in ASD, but not in others. CONCLUSION: ASDs were more frail and had more comorbidities than the other populations. In ASD, postsurgical outcomes and complication rates deteriorated as frailty and CCI increased, whereas surgery produced favorable outcomes and acceptable complication rates in DS and LSCS regardless of frailty and CCI. Careful patient selection and treatment of comorbidities before surgery may decrease complications and improve outcomes for the surgical treatment of ASD. LEVEL OF EVIDENCE: 4.

A 23-year-old man presented with difficulty walking and leg pain and numbness. MRI revealed a cystic mass at Th11-12 and a pineal-region tumour. The patient underwent surgery to resect the thoracic-level mass. The tumour adhered strongly to the neural tissue and could only be partially resected. On pathological examination, the resected tumour was diagnosed as a mature teratoma. The tumour regrew and disseminated within 3 months after resection. Both the spinal cord tumour and the tumour in the pineal region shrank significantly after chemotherapy and radiotherapy. Although the tumour was pathologically diagnosed as a mature teratoma, we suspect that the residual tumour contained an immature or malignant component. Thus, careful follow-up observation is mandatory after partial resection of a mature teratoma. In addition, because teratomas can disseminate in the central nervous system, the presence of teratoma should prompt an examination of both the spinal cord and brain.

BACKGROUND: Cost-utility analysis of surgery for degenerative lumber spondylolisthesis (DS) is essential for healthcare providers and patients to select appropriate treatment. The purpose of this study was to review the cost-utility of decompression alone versus decompression with fusion for DS. METHODS: A retrospective review of 99 consecutive patients who were treated for Meyerding grade 1 DS at two representative spine centers was performed. Patients with significant spinal instability were treated by decompression with fusion (F group, 40 patients); all others were treated by decompression surgery alone (D group, 59 patients). All patients were followed for three years. Demographic and radiographic data, health-related quality of life (HRQoL), and the direct cost for surgery were analyzed, and the incremental cost-effectiveness ratio (ICER) was determined using cost/quality-adjusted life years (QALY). RESULTS: There were no differences between the groups in baseline demographics (D vs. F: age 68 ± 9 vs. 66 ± 7 years; 37% vs. 40% female) or HRQoL (ODI: D, 41 ± 16 vs. F, 46 ± 13%). The F group had a higher initial-surgery cost ($18,992 ± 2932) but lower reoperation frequency (7%) than the D group ($7660 ± 2182 and 12%, respectively). The three-year total direct cost was higher for F than for D ($19,222 ± 3332 vs. $9668 ± 6,168, p = .01). ICER was higher for F at one year ($136,408 ± 187,911 vs. $237,844 ± 212,049, p < .01), but was comparable for F and D at three years (D, $41,923 ± 44,503 vs. F, $51,313 ± 32,849, p = .17). CONCLUSION: At the three-year follow-up, the two methods had comparable cost-utility. Both methods were cost-effective (defined as an ICER within three times the per-capita gross domestic product).

STUDY DESIGN: Multicenter retrospective study. OBJECTIVE: To validate and improve the predictive model for proximal junctional failure (PJF) with or without the bone mineral density (BMD) score. SUMMARY OF BACKGROUND DATA: PJF is a serious complication of surgery for adult spinal deformity (ASD). A predictive model for PJF was recently reported that has good accuracy, but does not include BMD, a known PJF risk factor, as a variable. METHODS: We included 145 surgically treated ASD patients who were older than 50 at the time of surgery and had been followed up for at least 2 years. Variables included age, sex, body mass index (BMI), fusion level, upper and lower instrumented vertebral (UIV and LIV) level, primary or revision surgery, pedicle subtraction osteotomy (PSO), Schwab-SRS type, and BMD. PJF was defined as a ≥ 20° increase from baseline (immediately postoperative) of the proximal junctional angle with concomitant deterioration of at least 1 SRS-Schwab sagittal modifier grade, or any proximal junctional kyphosis requiring revision. Decision-making trees were constructed using the C5.0 algorithm with 10 different bootstrapped models, and validated by a 7:3 data split for training and testing; 112 patients were categorized as training and 33 as testing samples. RESULTS: PJF incidence was 20% in the training samples. Univariate analyses showed that BMD, BMI, pelvic tilt (PT), UIV level, and LIV level were PJF risk factors. Our predictive model was 100% accurate in the testing samples with an AUC of 1.0, indicating excellent fit. The best predictors were (strongest to weakest): PT, BMD, LIV level (pelvis), UIV level (lower thoracic), PSO, global alignment, BMI, pelvic incidence minus lumbar lordosis, and age. CONCLUSION: A successful model was developed for predicting PJF that included BMD. Our model could inform physicians about patients with a high risk of developing PJF in the perioperative period. LEVEL OF EVIDENCE: 4.

BACKGROUND: Few studies have addressed in detail long-term degenerative changes in the cervical spine. In this study, we evaluated the progression of degenerative changes of the cervical spine that occurred over a 20-year period in an originally healthy cohort. We also sought to clarify the relationship between the progression of cervical degenerative changes and the development of clinical symptoms. METHODS: For this prospective follow-up investigation, we recruited 193 subjects from an original cohort of 497 participants who had undergone magnetic resonance imaging (MRI) of the cervical spine between 1993 and 1996. The subjects were asked about the presence or absence of cervical spine-related symptoms. Degenerative changes of the cervical spine were assessed on MRI using an original numerical grading system. The relationship between the progression of degenerative changes and the onset of clinical symptoms was evaluated by logistic regression analysis. RESULTS: Degeneration in the cervical spine was found to have progressed in 95% of the subjects during the 20-year period. The finding of a decrease in signal intensity of the intervertebral disc progressed in a relatively high proportion of the subjects in all age groups and occurred with similar frequency (around 60%) at all intervertebral disc levels. The rate of progression of other structural failures on MRI increased with age and was highest at C5-C6. The progression of foraminal stenosis was associated with the onset of upper-limb pain (odds ratio, 4.71 [95% confidence interval, 1.02 to 21.7]). CONCLUSIONS: A progression of degenerative changes in the cervical spine on MRI over the 20-year period was detected in nearly all subjects. There was no relationship between the progression of degeneration on MRI and the development of clinical symptoms, with the exception of an association found between foraminal stenosis and upper-limb pain. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

STUDY DESIGN: Case-only study. OBJECTIVE: The aim of this study was to confirm the association of rs11190870 with adolescent idiopathic scoliosis (AIS) severity in Japanese patients with AIS. SUMMARY OF BACKGROUND DATA: Although the association of rs11190870 with AIS susceptibility is replicated in multiple ethnics, the association of rs11190870 with curve severity is controversial. Since the previous studies are of small, we performed a replication study using far larger number of patients than previous studies. METHODS: A total of 1860 Japanese patients with AIS who had reached skeletal maturity or undergone surgical fusion were included in the study. We evaluated the association between rs11190870 and AIS progression for the entire group, and then for patients grouped according to a severe curve (a Cobb angle of ≥40°) or mild curve (a Cobb angle <30°). Because braces could affect the results of the present study, patients in the mild-curve group were divided according to whether or not they had worn a brace. We then evaluated associations between rs11190870 genotype and curve severity in these groups. RESULTS: The mean Cobb angles were 54.8° ± 12.1° in the severe-curve group and 24.4° ± 4.0° in the mild-curve group. The difference in rs11190870 risk-allele frequency between the severe- and mild-curve groups was evaluated. No significant differences were observed. We then examined the association of rs11190870 risk-allele frequency between patients in the mild- and severe-curve groups using the χ test for three models, and found a marginal association between rs11190870 and curve severity in the dominant model (P = 0.035, odds ratio = 1.51). CONCLUSION: We found no association between rs11190870 and curve severity using the criteria of previous study. However, we found a marginal association between rs11190870 and curve severity. Large-scale replication studies that consider skeletal maturity and brace history, including replication studies in other ethnic groups, would be helpful for clarifying the association. LEVEL OF EVIDENCE: 4.