Published papers

STUDY DESIGN: A retrospective multicenter cohort study. OBJECTIVE: The aim of this study was to identify the incidence and risk factors for UPROR within minimum 2-year follow-up in primary definitive fusion for pediatric spinal deformity. SUMMARY OF BACKGROUND DATA: Several previous reports have elucidated the incidence of complications after pediatric scoliosis surgery; however, there has been no study that described the incidence and risk factors for unplanned return to the operating room (UPROR) with long-term follow-up in surgery for pediatric scoliosis with every etiology. METHODS: We retrospectively extracted data of patients aged <19 years, from 14 institutes in Japan, who underwent primary definitive fusion surgery for spinal deformity between January 1, 2015 and December 31, 2017. The primary outcomes were the incidence of UPROR within the minimum 2-year follow-up period for any reason. Univariate and multivariate logistical analyses were conducted to identify potential risk factors associated with UPROR. RESULTS: We identified 1417 eligible patients (287 males and 1130 females) with a mean age of 13.9 years. UPROR for any reason within minimum 2-year follow-up was identified in 68 patients (4.8%). The most frequent cause for UPROR was implant failure found in 29 patients, followed by surgical site infection in 14 patients, junctional problems in 10 patients, and neurological complications in six patients. The multivariate logistic regression analysis revealed that a diagnosis of kyphosis (odds ratio [OR], 2.65; 95% confidence interval [CI] 1.16-6.04), etiology of congenital or structural type (OR 2.21; 95% CI 1.08-4.53), etiology of syndromic type (OR 2.67; 95% CI 1.27-5.64), and increased operation time of ≥300 minutes (OR 1.81; 95% CI 1.07-3.07) were the risk factors for the incidence of UPROR. CONCLUSION: The present multicenter study identified for the first time the incidence and risk factors for UPROR with minimum 2-year follow-up after primary definitive fusion surgery for pediatric spinal deformity with every etiology.Level of Evidence: 3.

Study Design.Retrospective multicenter study.Objective.To identify the impact of the intervertebral level of stenosis on surgical outcomes of posterior decompression for cervical spondylotic myelopathy (CSM).Summary of Background Data.As the upper affected cervical levels in elderly patients result from degenerative changes in the lower cervical levels with aging, it is usually difficult to determine the influence of the upper affected cervical levels on surgical outcomes after posterior decompression for CSM in older age.Methods.This study involved 636 patients with CSM who underwent posterior decompression. According to the most stenotic intervertebral level, patients were divided into upper (n = 343, the most stenotic intervertebral level was C2/3, C3/4, or C4/5) and lower (n = 293, the most stenotic intervertebral level was C5/6, C6/7, or C7/T1) cervical stenosis groups. Propensity score matching of the baseline factors (characteristics, comorbidities, and neurological function) was performed to compare surgical outcomes, the Japanese Orthopaedic Association (JOA) scores, and visual analog scale (VAS) for neck pain between the upper (n = 135) and lower (n = 135) cervical stenosis groups.Results.Before propensity score matching, age at surgery was older and pre- and postoperative JOA scores were lower in the upper cervical stenosis group (P < 0.001, P < 0.001, and P < 0.001, respectively). Following matching, baseline factors were comparable between the groups. Postoperative JOA scores, preoperative-to-postoperative changes in the JOA scores, and the JOA score recovery rate were not significantly different between the groups (P = 0.866, P = 0.825, and P = 0.753, respectively). No differences existed in postoperative VAS for neck pain and preoperative-to-postoperative changes in VAS for neck pain between the groups (P = 0.092 and P = 0.242, respectively).Conclusion.The intervertebral level of stenosis did not affect surgical outcomes after posterior decompression for CSM.Level of Evidence: 3.

Background: We conducted a finite element study to assess the effectiveness of a novel pedicle screw design with two alterations in the distal and proximal portions. Methods: Finite element (FE) models of 24 vertebrae were constructed using computed tomographic data. Pull-out strength of 4 different pedicle screws were compared. The basic screw design was a dual threaded one (PS0), in which the proximal portion is double-threaded (cortical thread), and the distal portion is single-threaded (cancellous thread). In PS1, the inter-thread double-core shape was added to PS0 in the distal portion. Compared to PS0, in PS2, the proximal portion was elongated by 5 mm. PS3 had both PS1 and PS2 features. In addition, the 24 vertebrae were classified into 3 groups based on volumetric bone mineral density (vBMD) of the vertebral body: low <120 mg/cm3, moderate 120–170 mg/cm3, and high >170 mg/cm3. Results: The mean pull-out strengths (±SD) were 1137 ± 500 N, 1188 ± 520 N, 1191 ± 512 N, and 1242 ± 538 N for PS0, PS1, PS2, and PS3, respectively. In PS1, there was significant difference in the incremental ratio of pull-out strength to PS0 between the low and high vBMD groups (3.7 ± 1.6% vs. 5.0 ± 1.0%, p = 0.006). In PS2, there was a significant difference in the incremental ratio to PS0 between the moderate and high vBMD groups (7.6 ± 4.0% vs. 3.3 ± 1.8%, p < 0.001). In PS3, there was a significant difference in the incremental ratio to PS0 between the moderate and high vBMD groups (12.1 ± 4.8% vs. 8.5 ± 2.1%, p = 0.003). Conclusions: The two design alterations showed the combined additive effect in the PS3 design. The moderate vBMD group has a balanced bone property to reflect the combined effects of the PS1 and PS2 design alterations.

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.

Background: The K-line in the neck-flexed position (FK-line) on radiography reflects dynamic factors and cervical alignment. Although the FK-line has been reported to affect the neurological recovery after muscle-preserving selective laminectomy for cervical spondylotic myelopathy (CSM), its influence on surgical outcomes after expansive open-door laminoplasty (ELAP) has not been investigated. Methods: We reviewed the surgical outcomes in 81 patients with multilevel CSM who underwent C4–C6 ELAP combined with C3 and C7 partial laminectomy using a laminoplasty plate and were followed up for at least 2 years. We defined the K-line (−) as some portion of a bony spur or the vertebral body crossing the FK-line, whereas the FK-line (+) was defined as that never crossing the FK-line. Patients were divided into the FK-line (+) (n = 61) and FK-line (−) groups (n = 20), and the surgical outcomes were compared between the groups. A multivariate analysis was performed to identify the factors that influenced the neurological outcomes. Results: The FK-line (−) group had a smaller C2–C7 angle, smaller C7 slope, greater postoperative increase in the C2–C7 sagittal vertical axis, greater kyphosis in cervical flexion and less lordosis in cervical extension, and higher incidence of postoperative residual spinal cord compression. The preoperative-to-postoperative changes in the Japanese Orthopedic Association (JOA) score and JOA score recovery rate (RR) were lower in the FK-line (−) group. The multiple linear regression analysis revealed that the K-line (−) (β = −0.327, P = 0.011) and high signal intensity (SI) changes on T2-weighted imaging (WI) combined with the low SI changes on T1-WI in the spinal cord (β = −0.320, P = 0.013) negatively affected the JOA score RR. Conclusions: The FK-line can be used for patients with CSM as a simple indicator of neurological outcomes after ELAP.

Laminectomy with instrumented fusion (LF) has demonstrated better prevention of ossification of posterior longitudinal ligament (OPLL) growth compared to laminoplasty (LP). There remains uncertainty, however, as to which surgical approach is more beneficial with respect to clinical outcomes and complications. We retrospectively reviewed 273 cervical OPLL patients of more than 3 levels, from the two institutions’ databases, who underwent LF or LP between January 1998 and January 2016. Each 273 patient (85 with LF, 188 with LP) was assessed for postoperative neurologic and radiologic outcomes, complications and reoperations. The mean length of follow-up was 40.11 months. There were baseline differences between cohorts. Overall, postoperative JOA recovery rate at last follow up was significantly better in the LP group with similar improvement in visual analog neck score. Postoperative C2-7 Cobb angle was decreased compared to baseline for both LF and LP cohorts, but there was no significant difference between groups. Complications occurred in 19 (22.35%) LF patients, and 11 (5.85%) LP patients, with higher incidence of C5 palsy and instrumentation failure in the LF group. Four LF patients (4.71%) and five LP patients (2.66%) underwent reoperation during the follow up period.

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 costeffectiveness of LIF in different ASD patient cohorts are warranted.

STUDY DESIGN: A multicenter retrospective case series. OBJECTIVE: The purpose of this study was to compare the clinical outcomes of a surgical treatment for adult spinal deformity (ASD) in the United States (US) with those in Japan (JP) in a matched cohort. SUMMARY OF BACKGROUND DATA: Surgical outcomes of thoracic-lumbar-sacral (TLS) spinal fusions in adult spinal deformity ASD patients who live in Asian countries are poorly understood. METHODS: A total of 300 surgically treated ASDs of age more than 50 years with the lowest instrumented vertebra at the pelvis and a minimum follow-up of 2 years (2y) were consecutively included. Patients were propensity-score matched for age, sex, levels fused, and 2y postop sagittal spinal alignment. Demographic, surgical, and radiographic parameters were compared between the US and JP groups. RESULTS: A total of 186 patients were matched by propensity score and were almost identical within these parameters: age (US vs. JP: 66 ± 8 vs. 65 ± 7 yr), sex (females: 90% vs. 89%), levels fused (10 ± 3 vs. 10 ± 2), 2y C7 sagittal vertical axis (C7SVA) (5 ± 5 vs. 5 ± 4 cm), 2y Pelvic incidence minus lumbar lordosis (9 ± 15° vs. 9 ± 15°), and 2y pelvic tilt (PT) (25 ± 10° vs. 24 ± 10°). Oswestry Disability Index (ODI) scores and Scoliosis Research Society patient questionnaire ((SRS-22) function and pain scores were similar at 2y between the US and JP groups (ODI: 27 ± 19% vs. 28 ± 14%, P = 0.72; SRS-22 function: 3.6 ± 0.9 vs. 3.6 ± 0.7, P = 0.54; SRS-22 pain: 3.6 ± 1.0 vs. 3.8 ± 0.8, P = 0.11). However, significantly lower satisfaction was observed in JP than in the US (SRS-22 satisfaction: 4.3 ± 0.9 vs. 4.0 ± 0.8, P < 0.01). CONCLUSION: Surgical treatment for ASD was similarly effective in patients in the US and in JP. However, satisfaction scores were lower in JP compared with the US. Differences in lifestyle and cultural expectations may impact patient satisfaction following ASD surgery.3.

Background: To evaluate surgical outcomes after posterior decompression surgery for lumbar spinal canal stenosis (LSS) in patients with diffuse idiopathic skeletal hyperostosis (DISH). Methods: The patients (n = 184; 132 males and 52 females; mean age 72.0 years; mean follow-up 30.7 months) who underwent posterior decompression surgery for LSS were identified and classified as either DISH (D) or non-DISH (N) based on whole spine radiograph findings. Data on age, gender, American Society of Anesthesiologists (ASA) classification, operation time, and estimated blood loss, were evaluated, while radiographic parameters were measured from radiographs obtained pre- and post-operatively. Results: Mean age and ASA classification were comparable between the two groups, while the proportion of males was significantly higher in the D group (87.5%) than in the N group (67.6%) (p = 0.016). Further, mean operation time was longer in the D group (89.0 min) than in the N group (73.7 min) (p = 0.036) and mean estimated blood loss was larger in the D group (98.7 g) than in the N group (51.9 g) (p = 0.006). At two years after surgery, the development of anterior translation was significantly higher in the D group (33.3%) than in the N group (17.3%) (p = 0.021). Improvements in ODI and SF-8 after the surgery were better in the N group than in the D group. Conclusions: Compared to LSS patients without DISH who also underwent posterior decompression surgery for LSS, surgery in patients with DISH was characterized by greater blood loss, longer operation time, increased translation at the decompressed segment, and poor recovery.

Context: Osseous epithelioid hemangioma is uncommon, and reports of epithelioid hemangiomas of the spine are especially rare. Study Design: Case report. Findings: A 43-year-old male was referred to our department with progressive gait disturbance. CT scans showed a lucent mass in the vertebral body at the T3 level. MRI of the thoracic spine showed a strongly enhanced mass compressing the spinal cord. The patient underwent laminectomy from T2 to T4, debulking of the tumor, and posterior fusion from T1 to T5. After the operation, the patient's neurological status improved significantly, and he was able walk without assistance. Histological examination determined that the tumor was an epithelioid hemangioma. The patient was treated with 40 Gy radiation for local control of the tumor. The patient could walk without difficulty 12 months after the surgery. Conclusion: This is a rare example of an epithelioid hemangioma that developed in the thoracic spine and compressed the spinal cord, and was treated successfully.

© 2017 Elsevier Inc. Background Context The relationship between gait pattern and the level of upper instrumented vertebra (UIV) in surgically treated patients with adult spinal deformity (ASD) has not been fully documented. Purpose This study aimed to assess the effect of UIV level for the gait pattern in ASD. Study Design/Setting A prospective case series was carried out. Patient Sample Thirty surgically treated consecutive female ASD with lumbosacral fusion (age 67.0±8.4 years; body mass index 22.7±2.4 kg/m 2 ; Cobb angle 49.9°±21.3°; coronal vertical axis 1.5±3.6 cm; C7 sagittal vertical axis [C7SVA] 9.3±5.3 cm; pelvic incidence-lumbar lordosis 35.4°±25.8°; and lean volume of the lower leg 5.5±0.9 kg) were categorized into upper thoracic [UT] group or lower thoracic [LT] group based on the level of UIV (UT; UIV T2–T5, LT; UIV T9–T11), and the gait pattern were compared before and after corrective spine surgery. Outcome Measures Scoliosis Research Society Patient Questionnaire, Oswestry Disability Index, and force plate analysis were the outcome measures. Methods All subjects underwent gait analysis on a custom-built force plate. Dual-energy X-ray absorptiometry. Subjects were followed-up for at least 2 years postoperation. Results The UT group had larger baseline Cobb angle, whereas the LT group had larger C7SVA (UT vs. LT; Cobb angle: 59.2±22.9 vs. 44.6±17.4° p=.03, C7SVA: 10.9±8.7 vs. 12.0±7.1 cm, p=.03). Preoperatively, no difference was found in gait velocity and stride between UT and LT group, whereas the right and left difference of step length was significantly large in UT group (velocity: 55.0±12.5 vs. 53.6±9.0 m/min, stride: 99.7±13.0 vs. 97.8±13.6 cm, step length; 10.4±4.9 vs. 5.6%±3.3%). Coronal and sagittal alignments were significantly improved in both groups (total; Cobb angle: 19.4°±10.6° C7SVA: 5.3±2.9 cm, PI–LL: 12.1°±5.1°). Gait pattern, stride, and velocity all improved significantly after surgery (total; velocity: 62.3±8.9m/min, stride: 106.8±12.3 cm, p=.01). The knee angle at the heel contact phase and hip range of motion (ROM) were also significantly improved at postoperation (total; hip ROM: preoperation: 29.2°±9.1° postoperation: 36.2°±4.8° knee angle; preoperation: 10.6°±6.6° postoperation: 4.4°±2.8°). No difference was observed for the pelvis and shoulder rotation on the horizontal plane at postoperation in both groups (total; pelvis rotation; preoperation: 7.4°±3.4° postoperation: 7.9°±2.4° shoulder rotation; preoperation: 7.4°±2.9° postoperation: 8.7°±3.6°). The head vertical deviation was also not changed postoperatively in both groups (preoperation: 3.1±0.9 cm, postoperation: 3.1±0.8 cm). Conclusions Both UT and LT groups achieved similar improvement of gait ability and pattern after surgery. Additional studies will be needed to further define the effect of UIV for the activity of daily living such as fast walking, stepping the stairs, or standing from the chair in ASDs.

© 2018 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).

© The Author(s) 2018. 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.

© The Author(s) 2019. Study design: A retrospective study of consecutive surgically managed cases of cervical spinal fractures and diffuse idiopathic skeletal hyperostosis (DISH) at our hospital from October 2006 to April 2016. Summary of background data: Prognostic factors have not been determined for cervical fractures in DISH. Objectives: To assess demographics, surgical techniques, and complications in cervical spinal cord injury with DISH and to evaluate factors affecting neurological prognosis. Methods: Patients’ medical records and radiographs were reviewed and analyzed for demographics, injury characteristics, surgical outcomes, perioperative complications, additional surgeries, and neurological prognosis. Neurological status was assessed by the American Spinal Injury Association (ASIA) grade at admission and discharge. Results: Of 38 patients (mean age 71.9 ± 8.8), 20 had type 1 fractures (through the disc space), 8 had type 2 (through the vertebral body), and 10 had type 3 (through disc and vertebral body). ASIA grades at admission included 14 ASIA-A, 4 ASIA-B, 7 ASIA-C, 8 ASIA-D, and 5 ASIA-E. All patients underwent posterior fusion with an average of 4.5 ± 2.5 instrumented vertebrae (range, 2–7) and six patients required secondary halo-vest fixation. Of 14 ASIA-A patients, 12 developed serious postsurgical pulmonary complications and 4 of these died within 6 months of surgery. Of the 38 patients, 13 improved more than one grade after treatment, 24 did not improve, and 1 deteriorated. In the 18 ASIA-A/B cases (complete motor paralysis), neither fracture type nor injury mechanism (e.g. a ground-level fall or high-energy trauma) correlated with neurological prognosis, but a time of 8 h or less from injury to surgery correlated significantly with an improvement from ASIA A/B to C/D (p < 0.01, Pearson’s χ 2 test). Conclusion: Patients with complete motor paralysis after a cervical fracture with DISH may recover to partial paralysis if surgically treated within 8 h of injury.

Study Design: Cross-sectional study. Objective: Patients who undergo intramedullary spinal surgery occasionally experience post-surgical chronic pain; however, the underlying mechanisms are not yet completely understood. Therefore, this study aimed to identify the cerebral structural changes in patients with post-surgical chronic myelopathic pain using voxel-based morphometry. Setting: Single university hospital in Tokyo, Japan. Methods: Forty-nine patients who had undergone intramedullary spinal surgery between January 2002 and April 2014 participated in this study. Participants were classified into two groups based on their post-surgical chronic pain intensity: control (numeric rating scale score of <3) and pain (numeric rating scale score of ≥3) groups. We compared pain questionnaire and brain MRI between two groups. Brain MRI data of each participants was analyzed using voxel-based morphometry. Results: Voxel-based morphometry revealed that the gray matter volume in the left supplementary motor area, left primary motor area, and left posterior cingulate cortex was higher in the pain group than that in the control group. In addition, the numeric rating scale score was significantly correlated with increased gray matter volume in the left primary motor area, left posterior cingulate cortex, and right superior parietal lobule. Conclusion: Present study elucidates the characteristic cerebral structural changes after an intramedullary spinal surgery using voxel-based morphometry and indicates that the structural changes in specific cerebral areas are associated with post-surgical chronic myelopathic pain.

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.

Chin on chest deformity caused by upper cervical kyphosis associated with ankylosing spon-dylitis is rare. A 66-year-old woman presented at our institute with chief complaints of diffi-culty 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 to-mography images at the C3/4 level suggested hemorrhage from the fracture site. Tracheos-tomy 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 fi-nally 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 vascu-lar injuries.

Study design: Diagnostic study. Objective: Although C5 palsy is a well-known potential complication after cervical procedure, the exact pathophysiology remains uncertain. Diffusion tensor tractography (DTT) has recently been proposed as a useful tool to examine quantitatively and non-invasively the pathology of spinal cord disorders. The purpose of this study is to determine the clinical interest of DTT in patients with C5 palsy after cervical laminoplasty. Setting: Single university hospital. Methods: Five patients with C5 palsy out of 108 patients after cervical laminoplasty were subjected to DTT using a 1.5 Tesla magnetic resonance imaging in our hospital between 2010 and 2012. For the tractography, two regions of interest (ROI) were placed at the C5 segmental level and the bilateral C4/5 intervertebral foramen level. Results: The postoperative number of tract fibers at the C5 segmental spinal cord level was significantly increased compared to the preoperative number, despite the C5 palsy. Analyses of two ROIs (at the C5 segmental level and the C4/5 intervertebral foramen level) showed that the number of tract fibers at the palsy side was significantly decreased compared to the intact side. Furthermore, in the patient who spontaneously recovered from C5 palsy within postoperative 6 months, a gradual augmentation of tract fibers was identified at the palsy side. Conclusions: Our findings suggest that DTT can document C5 palsy in detail, as the anatomical region between C5 segmental level and C4/5 intervertebral foramen level was potentially damaged in patients with C5 palsy after laminoplasty.

Ossification of the posterior longitudinal ligament (OPLL) can occur throughout the entire spine and can sometimes lead to spinal disorder. Although patients with OPLL sometimes develop physical limitations because of pain, the characteristics of pain and effects on activities of daily living (ADL) have not been precisely evaluated in OPLL patients. Therefore, we conducted a multi-center prospective study to assess whether the symptoms of cervical OPLL are different from those of cervical spondylosis (CS). A total of 263 patients with a diagnosis of cervical OPLL and 50 patients with a diagnosis of CS were enrolled and provided self-reported outcomes, including responses to the Japanese Orthopaedic Association (JOA) Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), JOA Back Pain Evaluation Questionnaire (JOABPEQ), visual analog scale (VAS), and SF-36 scores. The severity of myelopathy was significantly correlated with each domain of the JOACMEQ and JOABPEQ. There was a negative correlation between the VAS score for each domain and the JOA score. There were significantly positive correlations between the JOA score and the Mental Health, Bodily Pain, Physical Functioning, Role Emotional, and Role Physical domains of the SF-36. One-to-one matching resulted in 50 pairs of patients with OPLL and CS. Although there was no significant between-group difference in scores in any of the domains of the JOACMEQ or JOABPEQ, the VAS scores for pain or numbness in the buttocks or limbs were significantly higher in the CS group; however, there was no marked difference in low back pain, chest tightness, or numbness below the chest between the two study groups. The scores for the Role Physical and Body Pain domains of the SF-36 were significantly higher in the OPLL group than in the CS group, and the mean scores for the other domains was similar between the two groups. The results of this study revealed that patients with OPLL were likely to have neck and low back pain and restriction in ADL. No specific type of pain was found in patients with OPLL when compared with those who had CS.

Study Design: Multicenter retrospective study. Objectives: We aim to investigate features of cervical spondylotic myelopathy (CSM) associated with anterior cervical spondylolisthesis (ACS) during posterior decompression surgery. Methods: A total of 732 patients with CSM were enrolled, who underwent posterior decompression surgery between July 2011 and November 2015 at 17 institutions. The patients with ACS (group A), defined as an anterior slippage of ≥2 mm on plain radiographs, were compared with those without ACS (group non-A). Also, the characteristics of patients with ACS progression (group P), defined as postoperative worsening of ACS ≥2 mm or newly developed ACS, were investigated. Moreover, kyphosis was defined as C2-C7 angle in neutral position ≤−5°. The Japanese Orthopedic Association (JOA) scoring system was used for clinical evaluation. Results: Group A consisting of 62 patients (8.5%) had worse preoperative clinical status but comparable surgical outcomes to group non-A. Furthermore, ACS was associated with greater age, and the degree of slippage did not affect myelopathy grades. Seventeen patients (2.3%) were observed in group P, and preoperative ACS was a significant predisposing factor for the progression without clinical impact. Among the patients in group A, preoperative cervical kyphosis was a risk factor for lower JOA recovery rate. Conclusions: Although the presence of ACS increases the risk of postoperative progression, it is not a contraindication for posterior decompression. However, surgeons need to consider the indication of fusion surgery for the patients who have ACS accompanied by kyphosis because of the poor surgical outcomes.