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Objective: This study aimed to elucidate postoperative outcomes in patients with spinal metastases of prostate cancer, with a focus on patient-oriented assessments., Methods: This was a prospective multicenter registry study involving 35 centers. A total of 413 patients enrolled in the Japanese Association for Spine Surgery and Oncology Multicenter Prospective Study of Surgery for Metastatic Spinal Tumors were evaluated for inclusion. The eligible patients were followed for at least 1 year after surgery. The Frankel Classification, Eastern Cooperative Oncology Group Performance Status, visual analog scale for pain, face scale, Barthel Index, vitality index, indications for oral pain medication, and the EQ-5D-5L questionnaire were used for evaluating functional status, activities of daily living, and patient motivation., Results: Of the 413 eligible patients, 41 with primary prostate cancer were included in the study. The patient-oriented assessments indicated that the patients experienced postoperative improvements in quality of life and motivation in most items, with the improvements extending for up to 6 months. More than half of the patients with Frankel classifications B or C showed improved neurological function at 1 month after surgery, and most patients presented maintained or improved their classification at 6 months., Conclusion: Surgical intervention for spinal metastases of prostate cancer significantly improved neurological function, quality of life, and motivation of the patients. Consequently, our results support the validity of surgical intervention for improving the neurological function and overall well-being of patients with spinal metastases of prostate cancer., Competing Interests: Declaration of competing interest The Authors declare that there is no conflict of interest., (Copyright © 2024 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Despite the increasing prevalence of cervical odontoid fractures in older adults, the treatment strategy is controversial. The objectives of the current study are to investigate the prognosis and complications of cervical odontoid fractures in elderly patients and to identify factors associated with worsening of ambulation after 6 months., Methods: This multicenter, retrospective study included 167 patients aged 65 years or older with odontoid fractures. Patient demographic and treatment data were investigated and compared according to the treatment strategy. To determine associations with worsening ambulation after 6 months, we focused on the treatment strategies (nonsurgical treatment [collar immobilization or halo vest], conversion to surgery, or initial surgery) and patients' background., Results: Patients who received nonsurgical treatment were significantly older, and patients who underwent surgery had more Anderson-D'Alonzo type 2 fractures. Of the patients initially treated nonsurgically, 26% later underwent surgery. Numbers of complications, including death, and degrees of ambulation after 6 months did not differ significantly among treatment strategies. Patients who had worsened ambulation after 6 months were significantly more likely to be older than 80 years, to have needed assistance with walking before injury, and to have cerebrovascular disease. Multivariable analysis showed that a score of ≥2 on the 5-item modified frailty index (mFI-5) was significantly associated with worsening ambulation., Conclusions: Preinjury mFI-5 scores of ≥2 were significantly associated with worsening ambulation 6 months after treatment of cervical odontoid fractures in older adults., (Copyright © 2023 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Although previous studies have demonstrated the advantages of early surgery for traumatic spinal cord injury (SCI), the appropriate surgical timing for cervical SCIs (CSCIs) without bone injury remains controversial. Here, we investigated the influence of relatively early surgery within 48 h of injury on the neurological recovery of elderly patients with CSCI and no bone injury., Methods: In this retrospective multicenter study, we reviewed data from 159 consecutive patients aged ≥65 years with CSCI without bone injury who underwent surgery in participating centers between 2010 and 2020. Patients were followed up for at least 6 months following CSCI. We divided patients into relatively early (≤48 h after CSCI, n = 24) and late surgery (>48 h after CSCI, n = 135) groups, and baseline characteristics and neurological outcomes were compared between them. Multivariate analysis was performed to identify factors associated with neurological recovery., Results: The relatively early surgery group demonstrated a lower prevalence of cardiac disease, poorer baseline American Spinal Injury Association (ASIA) impairment scale grade, and lower baseline ASIA motor score (AMS) than those of the late surgery group (P < 0.030, P < 0.001, and P < 0.001, respectively). Although the AMS was lower in the relatively early surgery group at 6 months following injury (P = 0.001), greater improvement in this score from baseline to 6-months post injury was observed (P = 0.010). Multiple linear regression analysis revealed that relatively early surgery did not affect postoperative improvement in AMS, rather, lower baseline AMS was associated with better AMS improvement (P < 0.001). Delirium (P = 0.006), pneumonia (P = 0.030), and diabetes mellitus (P = 0.039) negatively influenced postoperative improvement., Conclusions: Although further validation by future studies is required, relatively early surgery did not show a positive influence on neurological recovery after CSCI without bone injury in the elderly., (Copyright © 2023 The Japanese Orthopaedic Association. All rights reserved.)

Background: Cervicobrachial pain frequently affects the quality of life (QOL) of the general public and has a significant economic impact on the health care systems of various countries. There are a number of treatment options for this disease, including widely-used drug therapy, but the effectiveness of each option is indeterminate, and there have been no published cost-effectiveness analysis studies so far. This prospective observational study aimed to examine the cost-effectiveness of drug treatment for cervicobrachial symptoms., Methods: A 6-month medication regimen for each of five frequently-prescribed drugs for cervicobrachial symptoms was administered to 322 patients at 24 centers in Japan. Outcome measures, including of the EuroQol Group 5D, Short Form-8, and Visual Analog Scale (VAS), were investigated at baseline and every month thereafter. Incremental cost-effectiveness ratios (ICERs) of the drug cost to quality-adjusted life years (QALYs) were calculated. A stratified analysis of patient characteristics was also performed to identify baseline factors potentially affecting cost-effectiveness., Results: The ICER of entire drug treatment for cervicobrachial symptoms was 7,491,640 yen. Compared with the reference willingness-to-pay, the ICER was assumed to not be cost-effective. A certain number of QALYs were gained during the first 3 months after the treatment intervention, but almost no QALYs were gained during the following 3 months. Stratified analysis showed that cost-effectiveness was extremely low for patients with high baseline VAS and high QOL., Conclusions: The available medications for cervicobrachial symptoms did not have excellent cost-effectiveness. Although a certain number of QALYs were gained during the first 3 months after medication, no QALYs were gained in the latter half of the study period, suggesting that it is not advisable to continue the medication needlessly., Level of Evidence: II, prospective cohort study., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest relevant to this work., (Copyright © 2023 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: The Japanese Orthopaedic Association (JOA) guideline for the management of lumbar spinal stenosis (LSS) was first published in 2011. Since then, the medical care system for LSS has changed and many new articles regarding the epidemiology and diagnostics of LSS, conservative treatments such as new pharmacotherapy and physical therapy, and surgical treatments including minimally invasive surgery have been published. In addition, various issues need to be examined, such as verification of patient-reported outcome measures, and the economic effect of revised medical management of patients with lumbar spinal disorders. Accordingly, in 2019 the JOA clinical guidelines committee decided to update the guideline and consequently established a formulation committee. The purpose of this study was to describe the formulation we implemented for the revision of the guideline, incorporating the recent advances of evidence-based medicine., Methods: The JOA LSS guideline formulation committee revised the previous guideline based on the method for preparing clinical guidelines in Japan proposed by the Medical Information Network Distribution Service in 2017. Background and clinical questions were determined followed by a literature search related to each question. Appropriate articles based on keywords were selected from all the searched literature. Using prepared structured abstracts, systematic reviews and meta-analyses were performed. The strength of evidence and recommendations for each clinical question was decided by the committee members., Results: Eight background and 15 clinical questions were determined. Answers and explanations were described for the background questions. For each clinical question, the strength of evidence and the recommendation were both decided, and an explanation was provided., Conclusions: The 2021 clinical practice guideline for the management of LSS was completed according to the latest evidence-based medicine. We expect that this guideline will be useful for all medical providers as an index in daily medical care, as well as for patients with LSS., Competing Interests: Declaration of competing interest All guideline formulation committee members confirmed the COI through self-reporting at the time of preparation of this manuscript. Committee members with any COI declined to vote for applicable recommendation decisions. No companies or any other organizations were directly involved in any text pertaining to the guideline, including the recommendations for all CQs and BQs., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Neuropathic pain (NeP) is pain provoked by damage or disease in the nervous system and about one in three Japanese patients with spinal disorders are highly likely to have NeP. The humanistic and economic burden of illness (BOI) of spine-related NeP represents unmet medical needs that should be addressed. The purpose of this targeted literature review was to synthesize the available evidence on the BOI of spine-related NeP in Japanese patients., Methods: PubMed and ICHUSHI were searched for relevant studies published between January 2010 and December 2020, in English or Japanese. The population included patients with one or more of prespecified spinal disorders and NeP, and outcomes of interest were data related to humanistic or economic burden., Results: Out of 32 studies that assessed the BOI of spine-related disorders in Japan, only six specifically assessed spine-related NeP. Among these studies, five different validated questionnaires were used to measure humanistic burden. Spine-related NeP was consistently shown to be related with a poorer health-related quality of life and higher levels of anxiety and depression compared to the general population as well as patients with nociceptive pain. No articles directly evaluating economic burden were identified in this search, so an exploratory analysis was conducted. Reduction in work productivity by people experiencing spine-related NeP in the whole of Japan were estimated to total JPY 172,266,780,480 per year., Conclusions: The humanistic burden of spine-related NeP on Japanese patients is considerable, not only physically but also mentally. Exploratory analysis of the economic burden illustrates the possibility of substantial societal costs associated with NeP. In order to better understand the depth of BOI and the unmet medical need caused by spine-related NeP, further studies on real-world outcomes are recommended., Competing Interests: Declaration of competing interest T Kaito has received consulting fees from Daiichi Sankyo Co., Ltd. K Okuizumi, S Takada, M Yokoyama and K Saito are full-time employees of Daiichi Sankyo Co., Ltd. B Crawford and K Usuba are full-time employees of Syneos Health. Syneos Health received funding from Daiichi Sankyo Co., Ltd. to conduct the data collection, data analysis and manuscript development., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by heterotopic bone formation in the posterior longitudinal ligament of the spine. Although the patients with OPLL are more common in the 60s and 70s, we know that there are markedly young patients (e.g., early 40s). However, to the best of our knowledge, there is few reports characterize young patients with cervical OPLL in terms of the imaging features, subjective symptoms, and ADL problems., Methods: This is the multicenter cross-sectional study. Two hundred and thirty-seven Japanese symptomatic patients with cervical OPLL confirmed by standard X-rays collected from 16 institutions belonging to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament formed by the Japanese Ministry of Health, Labor and Welfare were recruited. Whole spine CT data as well as demographic data such as age, gender, patients-based evaluations, and the 36-item Short Form Health Survey (SF-36) were evaluated., Results: Young group (≦ 45 years old) consisted of 23 patients (8 females and 15 males), accounting for 9.7% of the total. Their characteristics were high body mass index (BMI), significant involvement of trauma in the onset and deterioration of symptoms, and the predominance of thoracic OPLL. The patient-based evaluations did not show a significant difference between the young and non-young groups, or between the genders in the young group except for bodily pain (BP) of SF-36. Female patients in young group had significantly lower BP score of SF-36 than that of male in young group., Conclusions: Characteristics of young patients with cervical OPLL were high BMI, significant involvement of trauma in the onset and deterioration of symptoms, lower BP score of SF-36 in female, and the predominance of thoracic OPLL., Competing Interests: Declaration of competing interest None., (Copyright © 2021 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Surgical treatment for adolescent idiopathic scoliosis (AIS) has changed significantly with the advent of new medical devices and surgical procedures. Today, pre- and postoperative management differs widely between institutions. The purpose of this study is to establish consensus regarding the surgical management of AIS in Japan through the use of a questionnaire survey of experienced spine deformity surgeons., Methods: From February to March 2020, experienced spine deformity surgeons who perform more than 25 cases of AIS surgery annually were asked to respond to a questionnaire request regarding AIS surgical management formulated by the International Affairs Committee of the Japanese Scoliosis Society. For each of the questions, consensus was achieved upon a 70% agreement among respondents., Results: Responses were received from 25 of the 32 (78%) experienced spine deformity surgeons. The average age of the responding surgeons was 52 years with an average practice experience of 28 year. Consensus was achieved on 74 (76%) of the 97 aspects of care presented in the questionnaire and is broken down as follows: 12 of 17 items for preoperative management, all 5 items for perioperative management, 11 of 14 items for surgical technique, 9 of 15 items for implant selection, 6 of 8 items for bone grafting, 7 of 10 items for blood conservation, 5 of 7 items for postoperative management, all 17 items for postoperative evaluation, and 2 of 4 items for aftercare., Conclusions: Expert consensus was achieved on 74 aspects of the surgical management of AIS in Japan. In implant selection and aftercare, consensus was obtained in less than 70% of the aspects, revealing differences in AIS management between institutions. These findings on AIS surgery in Japan, informed by expert opinion, will conceivably help spine deformity surgeons determine appropriate surgical management of AIS., Competing Interests: Declaration of competing interest HA, TO, DK, HS, WS, HK, SS, MY, MI and DS have nothing to disclose. TK serves on the ethics review board of the Japanese Scoliosis Society., (Copyright © 2020 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Competing Interests: Declaration of competing interest None.

Background: Postoperative recovery of activities of daily living after surgery in elderly patients often takes a longer time because of their frailty. However, it is unclear how long it takes for patients with adult spinal deformity (ASD) to recover their abilities to live their daily lives in their home after corrective fusion surgery. This study aimed to investigate the length of hospital stay required to perform activities of daily living (ADL) in patients undergoing two-stage corrective fusion surgery for ASD in our institution and to detect factors associated with the length of hospital stay., Methods: Thirty-four consecutive female ASD patients (median age, 70 years) who underwent two-stage corrective fusion surgery (lateral lumbar interbody fusion at the first stage and posterior corrective fusion at the second stage) from T9 or T10 to the pelvis were included. The length of hospital stay from admission to return home was determined, and correlations between length of hospital stay and demographics, skeletal muscle mass, operative invasion and perioperative complications, and spino-pelvic alignment were investigated., Results: The median length of hospital stay was 51 days, exceeding 100 days in 25% of cases. Age at surgery (ρ = 0.545, p = 0.001), estimated glomerular filtration rate (ρ = -0.603, p < 0.001), age-adjusted Charlson comorbidity index (ρ = 0.437, p = 0.01), and preoperative pelvic incidence (ρ = 0.356, p = 0.04) were correlated with length of hospital stay. Preoperative skeletal muscle mass, preoperative spinal imbalance, perioperative changes in spino-pelvic alignment, operative invasion, and perioperative complications were not correlated with length of hospital stay., Conclusions: After >50 days, ADL performance of each patient reached the extent required for daily living to return home after two-stage corrective fusion surgery for ASD. Factors related to length of hospital stay were age and indices related to frailty., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Chronic low back pain (CLBP) is a major cause of chronic pain with nociceptive, neuropathic or both pain components, and a leading cause of disability. The objectives of this study were to determine the impact of background factors including previous use of drugs on outcomes of pharmacological therapy for CLBP in a nationwide multicenter prospective study., Methods: The subjects were 474 patients (male: 41.9%, median age: 73.0) with CLBP. Background factors that could influence outcomes after pharmacological treatment for 6 months were examined: age, gender, body mass index (BMI), duration of CLBP, osteoporosis, history of spinal surgery, history of malignant tumor, smoking habit, employment status (yes or no), exercise habit (frequency), number of live-in family members, having something to do for pleasure, Center for Epidemiologic Studies depression scale (CES-D) score, and medication at baseline. Japanese Orthopaedic Association (JOA) score, visual analogue scale (VAS) for LBP, JOA Back Pain Evaluation Questionnaire (JOABPEQ), Roland-Morris Disability Questionnaire (RDQ), Short-form 8-item health survey (SF-8), and EQ-5D were used for evaluation at baseline and after 6 months. Multivariate linear regression models were used in statistical analysis., Results: Drugs for neuropathic pain at baseline (p < 0.001), Tramacet® at baseline (p < 0.05), weak opioids at baseline (p < 0.05), older age (p < 0.001), long disease duration (p < 0.005), history of spinal surgery (p < 0.001), and smoking habit (p < 0.001) had significant negative effects on outcomes. Employment (p < 0.05), exercise habit (p < 0.05), and CED-D at baseline (p < 0.001) had positive effects on outcomes., Conclusions: This is the first study to identify significant prognostic factors for outcomes of pharmacological treatment of CLBP. The neuropathic pain component of CLBP at baseline is a major significant negative factor for most outcomes involving improved pain, activities of daily life, and quality of life. Treatment strategies developed with consideration of these factors may be advantageous for recovery from CLBP., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest relevant to the submitted work., (Copyright © 2020 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Backgrounds: Disadvantages of polyetheretherketone (PEEK) cages are their smooth and hydrophobic surfaces and their lack of osteoconductivity. Titanium (Ti) coated PEEK cage has been innovated to overcome these potential concerns. However, few well-designed studies have investigated the efficacy of Ti-coated PEEK cage on interbody fusion in humans. This study aimed to evaluate the efficacy of Ti coating on bone ongrowth at bone-implant surface by simultaneously comparing Ti-coated and uncoated PEEK cages in the same intervertebral space., Methods: This study is a prospective comparative study for the two different cages. Twenty-six subjects who underwent one-level instrumented posterior lumbar interbody fusion (PLIF) were included. Two PEEK cages [a plasma-sprayed Ti-coated (PTC-PEEK) and an uncoated PEEK cage] were inserted in the same intervertebral space. Fusion rates, cage subsidence, and vertebral cancellous condensation (VCC) around the cage, which indicates bone growth on the surface of each cage, were assessed by thin-slice computed tomography (CT) immediately (within 1 week) and at 3 months postoperatively. A functional radiograph was obtained at 3 and 12 months postoperatively., Results: Twenty-three subjects showed solid fusion at 3 months postoperatively (fusion rate, 88%). Cage subsidence was not observed. VCC was often observed around the PTC-PEEK cage as evaluated by completely synchronized CT images between immediately and at 3 months postoperatively. Quantified VCC around the cage was significantly larger in the PTC-PEEK cage than in the uncoated PEEK cage (P = 0.01)., Conclusions: The Ti-coated PEEK cage exhibits radiographic signs, suggesting bone ongrowth, as represented by VCC around the cage compared with that around the uncoated PEEK cage. The Ti-coated PEEK cage has the potential to promote solid fusion and to improve clinical outcomes in lumbar interbody fusion surgery., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

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/cm 3 , moderate 120-170 mg/cm 3 , and high >170 mg/cm 3 ., 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., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: The optimal surgical procedure for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL) remains controversial because there are few comprehensive studies investigating the surgical methods. Therefore, we conducted a systematic review and meta-analysis to evaluate evidence in the literature and compare the surgical outcomes of anterior decompression with fusion (ADF) and laminoplasty (LAMP), which are representative procedures for cervical OPLL., Methods: An extensive literature search was performed using PubMed, Embase, and the Cochrane Library to identify comparative studies of ADF and LAMP for cervical OPLL. The language was restricted to English, and the year of publication was from January 1980 to December 2018. We extracted outcomes from the studies, such as preoperative and postoperative Japanese Orthopaedic Association (JOA) score, cervical alignment, surgical complications and reoperation rate. Then, meta-analysis was performed for these surgical outcomes., Results: Twelve studies were obtained, including 1 prospective cohort study and 11 retrospective cohort studies. In the meta-analysis, neurological recovery rate in JOA score was greater in ADF than in LAMP, especially in patients with a large canal occupying ratio (≥60%) and preoperative kyphotic alignment. ADF also exhibited more favorable results in postoperative cervical alignment. In contrast, operating time and intraoperative blood loss were greater in ADF. Surgical complications were more frequently seen in ADF, leading to higher rates of reoperation., Conclusions: This systematic review and meta-analysis showed both the merits and shortcomings of ADF and LAMP. ADF resulted in more favorable neurological recovery compared to LAMP, especially for patients with massive OPLL and kyphotic alignment. Postoperative cervical lordosis was also better preserved in ADF. However, ADF was associated with greater surgical invasion and higher incidences of surgical complications., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: A consensus on the optimal surgical procedure for thoracolumbar OVF has yet to be reached due to the previous relatively small number of case series. The study was conducted to investigate surgical outcomes for osteoporotic vertebral fracture (OVF) in the thoracolumbar spine., Methods: In total, 315 OVF patients (mean age, 74 years; 68 men and 247 women) with neurological symptoms who underwent spinal fusion with a minimum 2-year follow-up were included. The patients were divided into 5 groups by procedure: anterior spinal fusion alone (ASF group, n = 19), anterior/posterior combined fusion (APSF group, n = 27), posterior spinal fusion alone (PSF group, n = 40), PSF with 3-column osteotomy (3CO group, n = 92), and PSF with vertebroplasty (VP + PSF group, n = 137)., Results: Mean operation time was longer in the APSF group (p < 0.05), and intraoperative blood loss was lower in the VP + PSF group (p < 0.05). The amount of local kyphosis correction was greater in the APSF and 3CO groups (p < 0.05). Clinical outcomes were approximately equivalent among all groups., Conclusion: All 5 procedures resulted in acceptable neurological outcomes and functional improvement in walking ability. Moreover, they were similar with regard to complication rates, prevalence of mechanical failure related to the instrumentation, and subsequent vertebral fracture. Individual surgical techniques can be adapted to suit patient condition or severity of OVF., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: There have been few reports on the incidence and risk factors of the complications after spinal fixation surgery for osteoporotic vertebral collapse (OVC) with neurological deficits. This study aimed to identify the incidence and risk factors of the complications after OVC surgery., Methods: In this retrospective multicenter study, a total of 403 patients (314 women and 89 men; mean age 73.8 years) who underwent spinal fixation surgery for OVC with neurological deficits between 2005 and 2014 were enrolled. Data on patient demographics were collected, including age, sex, body mass index, smoking, steroid use, medical comorbidities, and surgical procedures. All postoperative complications that occurred within 6 weeks were recorded. Patients were classified into two groups, namely, complication group and no complication group, and risk factors for postoperative complications were investigated by univariate and multivariate analyses., Results: Postoperative complications occurred in 57 patients (14.1%), and the most common complication was delirium (5.7%). In the univariate analysis, the complication group was found to be older (p = 0.039) and predominantly male (p = 0.049), with higher occurrence rate of liver disease (p = 0.001) and Parkinson's disease (p = 0.039) compared with the no-complication group. In the multivariate analysis, the significant independent risk factors were age (p = 0.021; odds ratio [OR] 1.051, 95% confidence interval [CI] 1.007-1.097), liver disease (p < 0.001; OR 8.993, 95% CI 2.882-28.065), and Parkinson's disease (p = 0.009; OR 3.636, 95% CI 1.378-9.599)., Conclusions: Complications after spinal fixation surgery for OVC with neurological deficits occurred in 14.1%. Age, liver disease, and Parkinson's disease were demonstrated to be independent risk factors for postoperative complications., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: We termed chronic neuropathic pain (NeP) in patients with diseases associated with spinal cord damage as "spinal cord-related pain syndrome". We conducted a survey of patients with the syndrome to assess the type and severity of NeP and its effect on QOL, and treatment modalities., Methods: This cross-sectional study was conducted in 185 patients recruited from 15 medical institutions. We analyzed the questionnaires sent to clinicians (basic information, magnetic resonance imaging (MRI) findings, type and effectiveness of medications) and patients [modified Neuropathic Pain Symptom Inventory (NPSI) and short form (SF)-36 healthy survey]., Results: The incidence of spinal cord-related pain syndrome was highest in patients with cervical spondylotic myelopathy, ossification of posterior longitudinal ligament (OPLL) and spinal cord injury. The number of patients with at-level pain was higher than those with below-level pain; dysesthesia/paresthesia, spontaneous and evoked pain types were mainly seen in patients with at-level pain and dysesthesia/paresthesia was common among those with below-level pain. NPSI score was higher than 10 in the majority of patients, and the subscore for dysesthesia/paresthesia was significantly the highest. The NPSI score was the highest in patients with severe hyperintense signal increase on MRI. The scores of all SF-36 sub-items were significantly lower than the national average. The majority of patients used non-steroid anti-inflammatory drugs and gabapentin/pregabalin; the latter was significantly effective for allodynia, compared with other medications, regardless of the pain level., Conclusions: The majority of patients with spinal cord-related pain syndrome suffered from severe NeP, which affected physical activity. The pain phenotype varied according to the level of the lesion and dysesthesia/paresthesia was the most intense. Compared with other medications, gabapentin/pregabalin was significantly effective especially for dysesthesia/paresthesia and evoked pain regardless of the pain level., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Chronic low back pain is a major health problem that has a substantial effect on people's quality of life and places a significant economic burden on healthcare systems. However, there has been little cost-effectiveness analysis of the treatments for it. Therefore, the purpose of this prospective observational study was to evaluate the cost-effectiveness of the pharmacological management of chronic low back pain., Methods: A total of 474 patients received pharmacological management for chronic low back pain using four leading drugs for 6 months at 28 institutions in Japan. Outcome measures, including EQ-5D, the Japanese Orthopaedic Association (JOA) score, the JOA back pain evaluation questionnaire (BPEQ), the Roland-Morris Disability Questionnaire, the Medical Outcomes Study SF-8, and the visual analog scale, were investigated at baseline and every one month thereafter. The incremental cost-utility ratio (ICUR) was calculated as drug cost over the quality-adjusted life years. An economic estimation was performed from the perspective of a public healthcare payer in Japan. Stratified analysis based on patient characteristics was also performed to explore the characteristics that affect cost-effectiveness., Results: The ICUR of pharmacological management for chronic low back pain was JPY 453,756. Stratified analysis based on patient characteristics suggested that the pharmacological treatments for patients with a history of spine surgery or cancer, low frequency of exercise, long disease period, low scores in lumbar spine dysfunction and gait disturbance of the JOA BPEQ, and low JOA score at baseline were not cost-effective., Conclusions: Pharmacological management for chronic low back pain is cost-effective from the reference willingness to pay. Further optimization based on patient characteristics is expected to contribute to the sustainable development of a universal insurance system in Japan., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Biologic agents (BAs) enabled not only a reduction of disease activity but also a slowing down of structural damage to the joints in patients with rheumatoid arthritis (RA). However, the incidence of cervical lesions in patients with RA is still high., Purpose: To elucidate the predictors for the progression of two different cervical lesions in patients with RA under BA treatment., Methods: Of 151 subjects who received more than two years of continuous BA treatment, 101 subjects who had cervical X-ray images taken at baseline and final visit were enrolled. The mean disease duration and mean radiography interval were 10.6 years and 4.4 years, respectively. The existence and progression of cervical lesions (atlanto-axial subluxation [AAS], vertical subluxation [VS], and subaxial subluxation [SS]) were investigated. And predictors for the AAS or VS progression were analyzed by multivariate logistic regression analysis., Results: The incidence of cervical lesions at baseline were no pre-existing cervical lesion (none) in 50 cases (50%), AAS only in 32 (32%), both AAS and VS in 12 (12%), and VS only in 7 cases (7%). In the none group, only 4 cases of AAS progression (8%) was observed during the follow-up. In contrast, in the groups with pre-existing cervical lesions, a high incidence of VS progression was observed (63% in the AAS only group, 58% in the AAS + VS group, and 71% in the VS only group). Multivariate regression analysis demonstrated that the DAS-CRP value at baseline (odds ratio [OR] = 9.23) and matrix metaloprotease-3 level at baseline (OR = 1.01) were significant predictors for the progression of AAS, and pre-existing AAS (OR = 18.38) was a sole significant predictor for the progression of VS., Conclusions: Cervical lesions progressed irrespective of disease activity after AAS development. Strict disease control before the development of AAS is crucial for preventing further progression and development of cervical lesions., (Copyright © 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Cortical pedicle screw placement is an attractive technique in terms of both fixation strength and less invasiveness. However, to insert the screw with penetrating cortical bone on the ideal trajectory is technically demanding. The use of three-dimensional (3D) patient-matched guides may facilitate the use of this technique., Purpose: To examine the accuracy of cortical screw placement using a patient-matched targeting guide with a cadaveric study assessing the accuracy., Methods: The 3D planning of the pedicle screw placement, including the location at which the screw would pass through the center of the pedicle, sagittal/transverse trajectory (angle), length, and diameter, was developed using 3D CAD design software. Three-dimensional guides based on the preoperative planning were created for three cadaveric specimens (L1 to S1, 36 pedicles). Screws (n = 18) and pins (n = 18) were placed using K-wire or drill-based guides, without X-ray exposure. Actual positioning was compared to the preoperative plan by superimposing the inserted screws/pins based on postoperative CT. The placement accuracy was graded based on the degree of perforation of the pedicle by the pedicle screw or pin using an acceptance criterion (no perforation; Grade A, 0-2 mm; Grade B, 2-4 mm; and Grade C, >4 mm). The mean deviation between the planned and inserted screw positions on the coronal plane at the midpoint of the pedicle was compared to the accuracy of screw guide for traditional pedicle screw trajectory (0.70 mm)., Results: Of 35 evaluated screws and pins, 32 (91.4%) were inserted completely inside the pedicle. All pedicle perforation was within 2 mm. The mean deviation from the plan at the midpoint of pedicle was 0.66 mm; thus, the accuracy was within the predefined criteria., Conclusions: Cortical pedicle screw placement using 3D-patient matched guides is accurate. Further clinical studies are required to confirm the radiographic and clinical effects., (Copyright © 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Object: This study aims to clarify the clinical potential of Hounsfield unit (HU), measured on computed tomography (CT) images, as a predictor of pedicle screw (PS) loosening, compared to bone mineral density (BMD)., Methods: A total of 206 screws in 52 patients (21 men and 31 women; mean age 68.2 years) were analyzed retrospectively. The screws were classified into two groups depending on their screw loosening status on 3-month follow-up CT (loosening screw group vs. non-loosening screw group). Preoperative HU of the trajectory was evaluated by superimposing preoperative and postoperative CT images using three-dimensional image analysis software. Age, sex, body mass index, screw size, BMD of lumbar, and HU of screw trajectory were analyzed in association with screw loosening. Multivariate logistic regression analysis was performed, and the thresholds for PS loosening risk factors were evaluated using a continuous numerical variable and receiver operating characteristic (ROC) curve analyses. The area under the curve (AUC) was used to determine the diagnostic performance, and values > 0.75 were considered to represent good performance., Results: The loosening screw group contained 24 screws (12%). Multivariate analysis revealed that the significant independent risk factors were not BMD but male sex [P = 0.028; odds ratio (OR) 2.852, 95% confidence interval (CI) 1.120-7.258] and HU of screw trajectory (P = 0.006; OR 0.989, 95% CI 0.980-0.997). ROC curve analysis demonstrated that the AUC for HU of screw trajectory for women was 0.880 (95% CI 0.798-0.961). The cutoff value was 153.5. AUC for men was 0.635 (95% CI 0.449-0.821), which was not considered to be a good performance., Conclusions: Low HU of screw trajectories was identified as a risk factor of PS loosening for women. For female patients with low HU, additional augmentation is recommended to prevent PS loosening., (Copyright © 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Lateral inter-body fusion (LIF) using cages with a large bone grafting space can lead to a shortage of autologous grafting materials. The use of artificial bone is an option to increase the volume of grafting materials. However, the rate of bony fusion for these materials compared to that of autologous bone is unclear., Methods: The bone fusion rate for artificial bone (HAp/Col) and autologous iliac bone (IBG) graft among 23 patients who had undergone LIF (total 66 disc levels) combined with multilevel posterior corrective fusion for the treatment of adult spinal deformity was retrospectively evaluated. To allow comparison, one of the two separate bone grafting holes in each LIF cage was filled with HAp/Col and the other, with IBG. The change in Hounsfield units (HU) inside the implanted holes at 1-year post surgery (PO1Y) from baseline and immediately after surgery and bony fusion between adjacent vertebrae, defined by the extent of trabecular continuity at PO1Y, were evaluated using computed tomography. Differences between the convex and concave sides as well as effects of the side of approach were investigated., Results: HU values increased significantly for IBG, from 228.9 at baseline to 286.1 at PO1Y (p < 0.001), with no change for HAp/Col. The fusion rate was higher for IBG (71.2%) than for HAp/Col (19.7%; p < 0.001). A significant effect of the location of the holes on fusion rate was identified for HAp/Col but not IBG. No effects of the side of approach were identified., Conclusions: A higher rate of fusion in LIF cages was obtained with IBG than with HAp/Col, with no effect of location of implantation (convex or concave) for IBG. Therefore, exclusive use of artificial bone, particularly on the convex side, should be avoided during LIF., (Copyright © 2018. Published by Elsevier B.V.)

Background: Although delayed union or pseudoarthrosis after lumbar arthrodesis has been recognized as a major radiographic complication, little has been known about the effect of fusion status on the patient's quality-of-life (QOL) outcome. The purpose of this study was to investigate the effects of fusion status after posterior lumbar interbody fusion (PLIF) on QOL outcomes by using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ)., Methods: Among 100 patients who underwent single level PLIF for spinal canal stenosis, 29 who had not achieved fusion (incomplete fusion group) and 29 age- and sex ratio-matched patients who had achieved fusion (fusion group) 6 months after surgery were enrolled. Overall clinical evaluation was performed before and 6 months after surgery: the physician determined the Japanese Orthopaedic Association Score for Low Back Pain (JOA score); the JOABPEQ and visual analogue scale (VAS) values were collected. The recovery rate of the JOA score, changes in all JOABPEQ subdomain scores and in the VAS values were calculated. All variables were compared between the groups., Results: The preoperative JOA scores, JOABPEQ scores of all subdomains, and VAS values of all categories did not differ between the groups. The recovery rate was higher in the fusion group than the incomplete fusion group (p = 0.0185). The changes in the JOABPEQ scores for walking ability and social life function were significantly greater in the fusion group than the incomplete fusion group (walking ability, p = 0.0172; social life function, p = 0.0191). The postoperative VAS values and changes in the VAS values for all categories did not differ between the groups., Conclusions: Incomplete fusion after PLIF correlated with poor improvement in walking ability and social life function. Therefore, the achievement of fusion after PLIF is essential to obtain better patient QOL outcomes.

Background: Anterior decompression with fusion (ADF) for patients with cervical ossification of the posterior longitudinal ligament (OPLL) is reportedly associated with a higher incidence of complications than is laminoplasty. However, the frequency of perioperative complications associated with ADF for cervical OPLL has not been fully established. The purpose of this study was to investigate the incidence of perioperative complications, especially neurological complications, following ADF performed to relieve compressive cervical myelopathy due to cervical OPLL., Methods: Study participants comprised 150 patients who had undergone ADF for cervical OPLL at 27 institutions between 2005 and 2008. Perioperative--especially neurological--complications occurring within 2 weeks after ADF were analyzed. Preoperative imaging findings, including Cobb angle, between C2 and C7 and occupying ratio of OPLL were investigated. Multivariate analysis with logistic regression was performed to identify independent risk factors for neurological complications., Result: Three patients (2.0 %) showed deterioration of lower-extremity function after ADF. One of the three patients had not regained their preoperative level of function 6 months after surgery. Upper-extremity paresis occurred in 20 patients (13.3 %), five of whom had not returned to preoperative levels 6 months after surgery. Patients with upper-extremity paresis showed significantly higher occupying ratios of OPLL, greater blood loss, longer operation times, fusion of more segments, and higher rates of cerebrospinal fluid leakage than those without paresis. Independent risk factors for upper-extremity paresis were a high occupying ratio of OPLL and large blood loss during surgery., Conclusions: The incidences of deterioration in upper- and lower-extremity functions were 13.3 % and 2.0 %, respectively. Patients with a high occupying ratio of OPLL are at higher risk of developing neurological deterioration.