論文 - 渡邉　航太

Surgical outcomes of spinal fusion for osteoporotic vertebral fracture in the thoracolumbar spine: Comprehensive evaluations of 5 typical surgical fusion techniques

Watanabe K., Katsumi K., Ohashi M., Shibuya Y., Hirano T., Endo N., Kaito T., Yamashita T., Fujiwara H., Nagamoto Y., Matsuoka Y., Suzuki H., Nishimura H., Terai H., Tamai K., Tagami A., Yamada S., Adachi S., Yoshii T., Ushio S., Harimaya K., Kawaguchi K., Yokoyama N., Oishi H., Doi T., Kimura A., Inoue H., Inoue G., Miyagi M., Saito W., Nakano A., Sakai D., Nukaga T., Ikegami S., Shimizu M., Futatsugi T., Ohtori S., Furuya T., Orita S., Imagama S., Ando K., Kobayashi K., Kiyasu K., Murakami H., Yoshioka K., Seki S., Hongo M., Kakutani K., Yurube T., Aoki Y., Oshima M., Takahata M., Iwata A., Endo H., Abe T., Tsukanishi T., Nakanishi K., Watanabe K., Hikata T., Suzuki S., Isogai N., Okada E., Funao H., Ueda S., Shiono Y., Nojiri K., Hosogane N., Ishii K.

Journal of Orthopaedic Science （Journal of Orthopaedic Science）  24 （ 6 ） 1020 - 1026 2019年11月

ISSN  09492658

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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.

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Lumbar spinal canal stenosis in patients with diffuse idiopathic skeletal hyperostosis: Surgical outcomes after posterior decompression surgery without spinal instrumentation

Okada E., Yagi M., Fujita N., Suzuki S., Tsuji O., Nagoshi N., Nakamura M., Matsumoto M., Watanabe K.

Journal of Orthopaedic Science （Journal of Orthopaedic Science）  24 （ 6 ） 999 - 1004 2019年11月

ISSN  09492658

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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.

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Risk, Recovery, and Clinical Impact of Neurological Complications in Adult Spinal Deformity Surgery

Yagi M., Michikawa T., Hosogane N., Fujita N., Okada E., Suzuki S., Tsuji O., Nagoshi N., Asazuma T., Tsuji T., Nakamura M., Matsumoto M., Watanabe K.

Spine （Spine）  44 （ 19 ） 1364 - 1370 2019年10月

ISSN  03622436

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Study Design. Multicenter retrospective case series. Objective. To report the risks, recovery, and clinical impact of neurological complications (NCs) in adult spinal deformity (ASD) surgery. Summary of Background Data. Although recent studies have reported the incidence of NCs in ASD surgery, few have addressed the recovery from and clinical impacts of NC. Methods. We reviewed records from a multicenter database for 285 consecutive surgically treated ASD patients who had reached a 2-year follow-up. NCs were categorized as sensory only or motor deficit (MD). Recovery was noted as none, partial, or complete, during hospitalization and at every postoperation visit. Uni- and multivariate risk analyses were performed to identify risk factors for MD. Results. NC developed in 29 (10%) patients within 30 days of surgery, of which 11 were permanent deficits (seven no recovery, and four partial recovery). MD developed in 14 (5%) patients, including one spinal cord injury. Seven MD patients required physical assistance at the latest follow-up. While NC patients experienced significant improvements in health-related quality of life at the 2-year follow-up, the health-related quality of life was significantly worse for the NC versus no-NC group at this time point. Univariate analyses revealed that Schwab-SRS types N and L, pelvic tilt, modified frailty index physical function, and an inferior SRS22 function domain at baseline were risk factors for MD. Among them, modified frailty index physical function, which represented a preoperative decline in activities of daily living, was identified as an independent risk factor for MD (OR: 4.0, 95% CI: 1.2-13.5, P = 0.03).Conclusions. NC developed in 10% of ASD surgery patients, with permanent deficits occurring in 4%. Half of the patients who developed MD required physical assistance, which contributed to the inferior clinical outcomes. Surgical intervention should be considered before severe activities of daily living decline to prevent NCs.

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Dietary habits had no relationship with adolescent idiopathic scoliosis: Analysis utilizing quantitative data about dietary intakes

Asakura K., Michikawa T., Takaso M., Minami S., Soshi S., Tsuji T., Okada E., Abe K., Takahashi M., Matsumoto M., Nishiwaki Y., Watanabe K.

Nutrients （Nutrients）  11 （ 10 ）  2019年10月

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Although several genetic and environmental factors have been identified as risk factors of adolescent idiopathic scoliosis (AIS), the influence of dietary intake has not been elucidated. We evaluated the association between AIS and dietary habits among female students. Junior high school girls aged 12 to 15 years in the Tokyo metropolitan area who underwent a second school screening for scoliosis were recruited. AIS was diagnosed by orthopedic surgeons specializing in scoliosis, using standing whole spine radiography. Students with a Cobb angle of ≥15° were classified into the AIS group, and others were considered healthy controls. Dietary assessment was performed using a validated diet history questionnaire. Dietary intakes were categorized into quintiles based on distribution, and crude and multivariable odds ratios and 95% confidence intervals for AIS for each quintile category of dietary variable were calculated, with the lowest quintile category used as a reference. In total, 2431 subjects were included in the analysis, and 47.8% of them were diagnosed with AIS. None of the selected nutrients or food groups was significantly associated with AIS. In conclusion, dietary habits may not be associated with AIS.

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The 5-Item Modified Frailty Index Is Predictive of Severe Adverse Events in Patients Undergoing Surgery for Adult Spinal Deformity

Yagi M., Michikawa T., Hosogane N., Fujita N., Okada E., Suzuki S., Tsuji O., Nagoshi N., Asazuma T., Tsuji T., Nakamura M., Matsumoto M., Watanabe K.

Spine （Spine）  44 （ 18 ） E1083 - E1091 2019年09月

ISSN  03622436

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Study Design.A retrospective review of 281 consecutive cases of adult spine deformity (ASD) surgery (age 55 ± 19 yrs, 91% female, follow-up 4.3 ± 1.9 yrs) from a multicenter database.Objective.To compare the value and predictive ability of the 5-item modified frailty index (mFI-5) to the conventional 11-item modified frailty index (mFI-11) for severe adverse events (SAEs).Summary of Background Data.Several recent studies have described associations between frailty and surgical complications. However, the predictive power and usefulness of the mFI-5 have not been proven.Methods.SAEs were defined as: Clavien-Dindo grade >3, reoperation required, deterioration of motor function at discharge, or new motor deficit within 2 years. The patients' frailty was categorized by the mFI-5 and mFI-11 (robust, prefrail, or frail). Spearman's rho was used to assess correlation between the mFI-5 and mFI-11. Univariate and multivariate Poisson regression analyses were conducted to analyze the relative risk of mFI-5 and mFI-11 as a predictor for SAEs in ASD surgery. Age, sex, and baseline sagittal alignment (Schwab-SRS classification subcategories) were used to adjust the baseline variance of the patients.Results.Of the 281 patients, 63 (22%) had developed SAE at 2 years. The weighted Kappa ratio between the mFI-5 and mFI-11 was 0.87, indicating excellent concordance across ASD surgery. Frailty was associated with increased total complications, perioperative complications, implant-related complications, and SAEs. Adjusted and unadjusted models showed similar c-statistics for mFI-5 and mFI-11 and a strong predictive ability for SAEs in ASD surgery. As the mFI-5 increased from 0 to ≥2, the rate of SAEs increased from 17% to 63% (P < 0.01), and the relative risk was 2.2 (95% CI: 1.3-3.7).Conclusion.The mFI-5 and the mFI-11 were equally effective predictors of SEA development in ASD surgery. The evaluation of patient frailty using mFI-5 may help surgeons optimize procedures and counsel patients.Level of Evidence: 4.

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Impact of fusion for adolescent idiopathic scoliosis on lung volume measured with computed tomography

Fujita N., Yagi M., Michikawa T., Yamada Y., Suzuki S., Tsuji O., Nagoshi N., Okada E., Tsuji T., Nakamura M., Matsumoto M., Watanabe K.

European Spine Journal （European Spine Journal）  28 （ 9 ） 2034 - 2041 2019年09月

ISSN  09406719

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Purpose: Although lung volume (LV) can be measured directly by computed tomography (CT), the literature regarding CT-assessed LV in adolescent idiopathic scoliosis (AIS) patients is limited, and the influence of posterior spinal fusion with instrumentation (PSF) on LV has not been established. This study aimed to identify factors associated with decreased LV after PSF in AIS patients. Methods: We retrospectively reviewed 111 consecutive AIS patients who were between 10 and 20 years of age and were treated by PSF at our facility. We assessed age at surgery, sex, height, body weight, Risser stage, Lenke classification, radiographic parameters, pulmonary function tests, and LV. Factors associated with a postoperative decrease in LV were identified by multivariable analysis. Results: The mean total LV had increased at the 2-year follow-up, although marginally significant (p =.06), and there was a significant increase in the left LV (p =.01) but not the right LV (p =.25). We observed a postoperative reduction in total LV, defined as a total LV postoperative/preoperative ratio < 0.9, in 20 of the 111 patients (18.0%). Univariable analysis showed a significant correlation between ≥ 11 fusion levels and postoperative LV reduction (OR 3.11, 95% CI 1.13–8.57). This factor remained significant in the multivariable analysis, which yielded an adjusted OR of 2.82 (95% CI 1.01–7.93) for postoperative LV reduction in patients with ≥ 11 fusion levels. Conclusion: Our data suggest that a longer fusion area is associated with postoperative LV reduction. Therefore, avoidance of a longer fusion area of ≥ 11 will be preferable for preserving LV. Graphical abstract: These slides can be retrieved under Electronic Supplementary Material.[Figure not available: see fulltext.].

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A review of my invention of expansive laminoplasty

Hirabayashi K., Watanabe K.

Neurospine （Neurospine）  16 （ 3 ） 379 - 382 2019年09月

ISSN  25866583

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Clinical indicators of surgical outcomes after cervical single open-door laminoplasty assessed by the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire

Nagoshi N., Tsuji O., Okada E., Fujita N., Yagi M., Tsuji T., Nakamura M., Matsumoto M., Watanabe K.

Spinal Cord （Spinal Cord）  57 （ 8 ） 644 - 651 2019年08月

ISSN  13624393

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Study design: Retrospective cohort study. Objectives: The old-version JOA score for cervical myelopathy (CM) is an evaluation system performed by medical providers that focuses only on neurological function. The purpose of this study was to evaluate patient-reported outcomes using the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), and to clarify clinical factors that affect the therapeutic effectiveness for CM. Setting: Single institute in Japan. Methods: We reviewed surgical outcomes for 126 CM patients who were treated by single open-door laminoplasty and were followed at least 2 years. We assessed clinical information, JOACMEQ, JOA scores, and radiographic parameters. Patients were grouped according to effective or ineffective surgical outcomes as defined by the JOACMEQ using logistic regression analyses. Results: Laminoplasty resulted in functional improvement in the cervical spine and extremities for 40–50% of the patients, while bladder function showed only minimal recovery. Multivariable analyses revealed that a significant postoperative reduction in neck or shoulder pain influenced the effective functional recovery of the cervical spine. A reduction in arm or hand pain favorably affected the postoperative upper extremity function. Lower age and a postoperative decrease in limb pain were correlated with significantly improved function of the lower extremities. A postoperative reduction in arm pain enhanced the QOL recovery. Conclusions: The JOACMEQ makes it possible to analyze multiple aspects of surgical outcomes for patients who undergo cervical spine surgery. Open-door laminoplasty did not provide favorable results for some patients, which highlights the importance of assessing the indications for this procedure and managing postoperative pain.

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TBX6-associated congenital scoliosis (TACS) as a clinically distinguishable subtype of congenital scoliosis: further evidence supporting the compound inheritance and TBX6 gene dosage model

Liu J., Wu N., Yang N., Takeda K., Chen W., Li W., Du R., Liu S., Zhou Y., Zhang L., Liu Z., Zuo Y., Zhao S., Blank R., Pehlivan D., Dong S., Zhang J., Shen J., Si N., Wang Y., Liu G., Li S., Zhao Y., Zhao H., Chen Y., Zhao Y., Song X., Hu J., Lin M., Tian Y., Yuan B., Yu K., Niu Y., Yu B., Li X., Chen J., Yan Z., Zhu Q., Meng X., Chen X., Su J., Zhao X., Wang X., Ming Y., Li X., Raggio C.L., Zhang B., Weng X., Zhang S., Zhang X., Watanabe K., Matsumoto M., Jin L., Shen Y., Sobreira N.L., Posey J.E., Giampietro P.F., Valle D., Liu P., Wu Z., Ikegawa S., Lupski J.R., Zhang F., Qiu G.

Genetics in Medicine （Genetics in Medicine）  21 （ 7 ） 1548 - 1558 2019年07月

ISSN  10983600

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Purpose: To characterize clinically measurable endophenotypes, implicating the TBX6 compound inheritance model. Methods: Patients with congenital scoliosis (CS) from China(N = 345, cohort 1), Japan (N = 142, cohort 2), and the United States (N = 10, cohort 3) were studied. Clinically measurable endophenotypes were compared according to the TBX6 genotypes. A mouse model for Tbx6 compound inheritance (N = 52) was investigated by micro computed tomography (micro-CT). A clinical diagnostic algorithm (TACScore) was developed to assist in clinical recognition of TBX6-associated CS (TACS). Results: In cohort 1, TACS patients (N = 33) were significantly younger at onset than the remaining CS patients (P = 0.02), presented with one or more hemivertebrae/butterfly vertebrae (P = 4.9 × 10‒8), and exhibited vertebral malformations involving the lower part of the spine (T8–S5, P = 4.4 × 10‒3); observations were confirmed in two replication cohorts. Simple rib anomalies were prevalent in TACS patients (P = 3.1 × 10‒7), while intraspinal anomalies were uncommon (P = 7.0 × 10‒7). A clinically usable TACScore was developed with an area under the curve (AUC) of 0.9 (P = 1.6 × 10‒15). A Tbx6-/mh (mild-hypomorphic) mouse model supported that a gene dosage effect underlies the TACS phenotype. Conclusion: TACS is a clinically distinguishable entity with consistent clinically measurable endophenotypes. The type and distribution of vertebral column abnormalities in TBX6/Tbx6 compound inheritance implicate subtle perturbations in gene dosage as a cause of spine developmental birth defects responsible for about 10% of CS.

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A 20-year prospective longitudinal MRI study on cervical spine after whiplash injury: Follow-up of a cross-sectional study

Daimon K., Fujiwara H., Nishiwaki Y., Okada E., Nojiri K., Shimizu K., Ishihama H., Fujita N., Ichihara D., Tsuji T., Nakamura M., Matsumoto M., Watanabe K.

Journal of Orthopaedic Science （Journal of Orthopaedic Science）  24 （ 4 ） 579 - 583 2019年07月

ISSN  09492658

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Background: Some patients suffer from long-lasting symptoms after whiplash injury. However, there are few reports on the long-term changes in the cervical spine after whiplash injury using imaging tests. The purpose of this longitudinal study was to determine the changes on MRI of the cervical spine 20 years after whiplash injury, and to examine the relationships between changes in the cervical spine on MRI and changes in related clinical symptoms. Methods: Eighty-one subjects finally participated in this study (follow-up rate 16%). The mean follow-up duration was 21.7 years. All subjects filled out a questionnaire about their clinical symptoms. The MRI findings were assessed using numerical grading system applied in the original study. Statistic analyses were used to investigate whether the progression of each MRI finding was associated with the severity of neck pain, stiff shoulders, dizziness and tinnitus. Results: All subjects had complained of some clinical symptoms in the original study: 71 had neck pain, 53 stiff shoulders, and others. In the present study, 66 subjects (81.5%) complained of some clinical symptoms: 57 had stiff shoulders, 20 neck pain, and others. The progression of degeneration on MRI was observed in 95% of the subjects, with C4/5 and 5/6 being the most frequently involved levels. Changes in the severity of neck pain, stiff shoulders, dizziness and tinnitus over 20 years were not significantly associated with the progression of degenerative changes in the cervical spine on MRI. Conclusions: Twenty years after whiplash injury, 95% of the subjects showed a progression of degeneration in the cervical spine. The progression of the intervertebral disc degeneration in the cervical spine on MRI after whiplash injury was not significantly associated with changes in the severity of related clinical symptoms, indicating that the degenerative changes on MRI may reflect the physiological aging process rather than post-traumatic sequelae.

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Modic changes in the cervical spine: Prospective 20-year follow-up study in asymptomatic subjects

Tsuji T., Fujiwara H., Nishiwaki Y., Daimon K., Okada E., Nojiri K., Watanabe M., Katoh H., Shimizu K., Ishihama H., Fujita N., Nakamura M., Matsumoto M., Watanabe K.

Journal of Orthopaedic Science （Journal of Orthopaedic Science）  24 （ 4 ） 612 - 617 2019年07月

ISSN  09492658

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Background: Few studies have characterized the development of Modic changes in the cervical spine over time. We evaluated Modic changes of the cervical spine that developed over a 20-year period in a healthy cohort, and sought to clarify the relationship between Modic changes and the development of clinical symptoms. Methods: For this multicenter prospective cohort study, we recruited 193 subjects from an original cohort of asymptomatic volunteers who underwent MRI of the cervical spine between 1993 and 1996. Each cervical level from C2/3 to C7/T1 (total n = 1158 intervertebral levels) was assessed on current MRIs as normal or showing type 1, 2, or 3 Modic change, and we asked about symptoms related to the cervical spine. Relationships between the presence of Modic changes and patient characteristics, pre-existing disc degenerations or clinical symptoms were evaluated by logistic regression analysis. Results: After 20-year follow-up, Modic changes affected 31 subjects (16.1%) at 47 intervertebral disc levels. Of these 47 intervertebral disc levels, type 2, found at 30 levels (63.8%), was the most frequent, followed by type 1 at 15 levels (31.9%) and type 3 at two levels (4.3%). The most frequent changes were observed at the C5/6 segment with type 2 Modic changes. The presence of Modic changes correlated with pre-existing posterior disc protrusion (odds ratio 3.31, 95% confidence interval 1.21–9.05) and neck pain (odds ratio 2.71, 95% confidence interval 1.08–6.80). Conclusions: In the cervical spine over a 20-year period, type 2 Modic changes were most frequent at the C5/6 segment. The Modic changes were associated with pre-existing disc degeneration and neck pain but not with age, BMI, smoking, shoulder stiffness, arm pain or numbness.

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Spinal fractures in patients with Diffuse idiopathic skeletal hyperostosis:A nationwide multi-institution survey

Okada E., Yoshii T., Yamada T., Watanabe K., Katsumi K., Hiyama A., Watanabe M., Nakagawa Y., Okada M., Endo T., Shiraishi Y., Takeuchi K., Matsunaga S., Maruo K., Sakai K., Kobayashi S., Ohba T., Wada K., Ohya J., Mori K., Tsushima M., Nishimura H., Tsuji T., Okawa A., Matsumoto M., Watanabe K.

Journal of Orthopaedic Science （Journal of Orthopaedic Science）  24 （ 4 ） 601 - 606 2019年07月

ISSN  09492658

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Background: Diffuse idiopathic skeletal hyperostosis (DISH) increases the spine's susceptibility to unstable fractures that can cause neurological deterioration. However, the detail of injury is still unclear. A nationwide multicenter retrospective study was conducted to assess the clinical characteristics and radiographic features of spinal fractures in patients with DISH. Methods: Patients were eligible for this study if they 1) had DISH, defined as flowing ossification along the anterolateral aspect of at least four contiguous vertebral bodies, and 2) had an injury in the ankylosing spine. This study included 285 patients with DISH (221 males, 64 females; mean age 75.2 ± 9.5 years). Results: The major cause of injury was falling from a standing or sitting position; this affected 146 patients (51.2%). Diagnosis of the fracture was delayed in 115 patients (40.4%). Later neurological deterioration by one or more Frankel grade was seen in 87 patients (30.5%). The following factors were significantly associated with neurological deficits: delayed diagnosis (p = 0.033), injury of the posterior column (p = 0.021), and the presence of ossification of the posterior longitudinal ligament (OPLL) (p < 0.001). The majority of patients (n = 241, 84.6%) were treated surgically, most commonly by conventional open posterior fixation (n = 199, 69.8%). Neurological improvement was seen in 20.0% of the conservatively treated patients, and in 47.0% of the patients treated surgically. Conclusions: Minor trauma could cause spinal fractures in DISH patients. Delayed diagnosis, injury of the posterior column, and the presence of OPLL were significantly associated with neurological deterioration. Patients with neurological deficits or unstable fractures should be treated by fixation surgery.

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Treatment for frailty does not improve complication rates in corrective surgery for adult spinal deformity

Yagi M., Michikawa T., Hosogane N., Fujita N., Okada E., Suzuki S., Tsuji O., Nagoshi N., Asazuma T., Tsuji T., Nakamura M., Matsumoto M., Watanabe K.

Spine （Spine）  44 （ 10 ） 723 - 731 2019年05月

ISSN  03622436

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Study Design.A retrospective multicenter database review of 240 consecutive patients at least 21 years of age (mean 58±17, range 22-79) who underwent surgery for adult spinal deformity (ASD) and were followed at least 2 years.Objective.To investigate how treatment for frailty affects complications in surgery for ASD.Summary of Background Data.Several recent studies have focused on associations between frailty and surgical complications. However, it is not clear whether treating frailty affects complication rates in surgery for ASD.Methods.Patients were categorized as robust (R group), prefrail, or frail based on the modified frailty index (mFI); prefrail and frail patients were divided by good control of frailty (G group), defined as treatment following the appropriate guidelines for each mFI factor, or poorly controlled frailty (PC group). We compared clinical outcomes and perioperative and 2-year complications between the three groups.Results.Of the 240 patients, 142 (59%) were robust, 81 (34%) were prefrail, and 17 (7%) were frail. Among the frail and prefrail patients, 71 (72%) were classified as G and 27 (28%) as PC. The perioperative complication rate was similar in the G and PC groups (32% vs. 37%) but was significantly lower in the R group (15%, P<0.01). The age-and sex-Adjusted odds ratio for 2-year complications was not different in the P group when the G group was referenced (odds ratio 1.3 [0.5-3.2], P=0.63). In the G and PC groups, which had similar 2-year outcomes, the Scoliosis Research Society-22 function and total scores were significantly lower than in the R group (function: R 3.9±0.7, G 3.5±0.7, P 3.3±0.6; total: R 3.9±0.6, 3.7±0.7, 3.4±0.6; P<0.01).Conclusion.Regardless of its treatment status, frailty increases the risk of complications and inferior clinical outcomes in ASD surgery. Surgeons should routinely evaluate frailty and inform patients of frailty-related risks when considering surgery for ASD.Level of Evidence: 4.

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A multiethnic meta-analysis defined the association of rs12946942 with severe adolescent idiopathic scoliosis

Takeda K., Kou I., Otomo N., Grauers A., Fan Y.H., Ogura Y., Takahashi Y., Momozawa Y., Einarsdottir E., Kere J., Kawakami N., Tsuji T., Uno K., Suzuki T., Ito M., Minami S., Kotani T., Sakuma T., Yanagida H., Taneichi H., Yonezawa I., Sudo H., Chiba K., Hosogane N., Nishida K., Kakutani K., Akazawa T., Kaito T., Watanabe K., Harimaya K., Taniguchi Y., Shigematsu H., Demura S., Iida T., Kono K., Okada E., Fujita N., Yagi M., Matsumoto M., Qiu Y., Song Y.Q., Gerdhem P., Watanabe K., Ikegawa S.

Journal of Human Genetics （Journal of Human Genetics）  64 （ 5 ） 493 - 498 2019年05月

ISSN  14345161

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Adolescent idiopathic scoliosis (AIS) is the most common type of scoliosis. Controlling its curve progression is the most important clinical task. Although recent genome-wide association studies (GWASs) identified several susceptibility loci associated with the development of AIS, the etiology of curve progression has been still unknown. Our previous GWAS has identified that rs12946942 showed significant association with severe AIS. To confirm the association, we conducted an international meta-analysis using four cohorts with different ethnicity. We analyzed 2272 severe AIS cases and 13,859 controls in total, and found the replication of significant association of rs12946942 (combined P = 7.23×10 −13 ; odds ratio = 1.36, 95% confidence interval = 1.25−1.49). In silico analyses suggested that SOX9 is the most likely susceptibility gene for AIS curve progression in the locus.

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Changes in sagittal alignment after surgical excision of thoracic spinal cord tumors in adults

Kobayashi Y., Kawabata S., Nishiyama Y., Tsuji O., Okada E., Fujita N., Yagi M., Watanabe K., Matsumoto M., Nakamura M., Nagoshi N.

Spinal Cord （Spinal Cord）  57 （ 5 ） 380 - 387 2019年05月

ISSN  13624393

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Study design: Retrospective chart audit. Objectives: This study investigated changes in sagittal alignment in adults after excision of thoracic spinal cord tumors without spinal fixation. Setting: Single-center study at an academic orthopedic department in Japan. Methods: We retrospectively reviewed records for 32 adults who underwent excision of thoracic spinal cord tumors by multilevel laminectomies without fixation. The participants were divided according to whether the tumor was in the upper (T1–4), middle (T5–8), or lower (T9–12) thoracic spine. We analyzed parameters such as age, sex, time in surgery and estimated blood loss, follow-up period, and preoperative and follow-up the Japanese Orthopaedic Association (JOA) scores and radiographs. Results: Postoperative T1-12 kyphotic changes did not correlate with age, the number of resected laminae, or preoperative T1-12 kyphosis. JOA recovery rates were similar regardless of the tumor location. Participants with tumors in the upper thoracic spine had significant postoperative increases in T1–4 kyphosis, T1 slope (p <.05, respectively). In contrast, there were no significant changes in alignment in participants with tumors in the middle or lower thoracic spine. Conclusion: Even without fixation, sagittal alignment did not change after surgery to excise tumors in the middle and lower thoracic spine, indicating that fixation may not be necessary when excising spinal cord tumors in this region. In contrast, postoperative kyphosis may increase when the tumor is in the upper thoracic spine.

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Plate fixation of expansive open-door laminoplasty decreases the incidence of postoperative C5 palsy

Kobayashi Y., Matsumaru S., Kuramoto T., Nagoshi N., Iwanami A., Tsuji O., Okada E., Fujita N., Yagi M., Tsuji T., Ogawa J., Nakamura M., Masumoto M., Ishii K., Watanabe K.

Clinical Spine Surgery （Clinical Spine Surgery）  32 （ 4 ） E177 - E182 2019年05月

ISSN  23800186

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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.

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Spinal fractures in diffuse idiopathic skeletal hyperostosis: Advantages of percutaneous pedicle screw fixation

Okada E., Shiono Y., Nishida M., Mima Y., Funao H., Shimizu K., Kato M., Fukuda K., Fujita N., Yagi M., Nagoshi N., Tsuji O., Ishii K., Nakamura M., Matsumoto M., Watanabe K.

Journal of Orthopaedic Surgery （Journal of Orthopaedic Surgery）  27 （ 2 ）  2019年05月

ISSN  10225536

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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.

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Spinal fractures in patients with diffuse idiopathic skeletal hyperostosis: Clinical characteristics by fracture level

Okada E., Shimizu K., Kato M., Fukuda K., Kaneko S., Ogawa J., Yagi M., Fujita N., Tsuji O., Suzuki S., Nagoshi N., Tsuji T., Nakamura M., Matsumoto M., Watanabe K.

Journal of Orthopaedic Science （Journal of Orthopaedic Science）  24 （ 3 ） 393 - 399 2019年05月

ISSN  09492658

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© 2018 The Japanese Orthopaedic Association Background: Diffuse idiopathic skeletal hyperostosis (DISH) makes the spine prone to unstable fractures with neurological deterioration. This study was conducted to assess clinical and radiographic features of spinal fractures in DISH by the level of spinal injury, and to evaluate the optimal treatment for each level. Methods: A multicenter retrospective study over a 5-year period, including 46 patients (35 males; 11 females) with a mean age of 77.2 ± 9.7 years at the time of injury. By fracture level, there were 7 cervical (15.2%), 25 thoracic (54.3%), and 14 lumbar (30.4%) fractures. We recorded the cause of injury, whether diagnosis was delayed, and neurological status by Frankel grade. Ossification and fracture patterns were assessed by CT-multi-planar reconstruction (MPR). Results: Neurological status immediately after the cervical-spine injury was C (28.6%) or E (71.4%); after thoracic injury, C (12.0%) or E (88.0%); and after lumbar injury, D (21.4%) or E (78.6%). Inability to walk at admission was more frequent in patients with a spinal-cord injury above the lumbar level (P = .033). Vertebral-body fractures were observed in 14.3% of the cervical injuries, 80.0% of the thoracic injuries, and 50.0% of the lumbar injuries (P = .004). Most patients with a cervical fracture had a disc-level fracture (85.7%). Posterior-column ankylosis was observed in 14.3% of the cervical-fracture group, 72.0% of the thoracic-fracture group, and 78.6% of the lumbar-fracture group (P = .008). Conclusion: Ossification and fracture patterns in patients with DISH varied distinctly by the level of spinal injury. Intervertebral-disc fractures were frequently observed in the cervical spine. Delayed diagnosis, vertebral-body fracture, and posterior-column ankylosis were observed in the thoracolumbar spine. This study recommends 3 above and 3 below fusion, to avoid instrumentation failure in the fixation of spinal fracture in patients with DISH.

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Surgical risk stratification based on preoperative risk factors in adult spinal deformity

Yagi M., Hosogane N., Fujita N., Okada E., Suzuki S., Tsuji O., Nagoshi N., Asazuma T., Tsuji T., Nakamura M., Matsumoto M., Watanabe K.

Spine Journal （Spine Journal）  19 （ 5 ） 816 - 826 2019年05月

ISSN  15299430

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© 2018 Elsevier Inc. BACKGROUND CONTEXT: Corrective surgery for adult spinal deformity (ASD) improves health-related quality of life but has high complication rates. Predicting a patient's risk of perioperative and late postoperative complications is difficult, although several potential risk factors have been reported. PURPOSE: To establish an accurate, ASD-specific model for predicting the risk of postoperative complications, based on baseline demographic, radiographic, and surgical invasiveness data in a retrospective case series. STUDY DESIGN/SETTING: Multicentered retrospective review and the surgical risk stratification. PATIENT SAMPLE: One hundred fifty-one surgically treated ASD at our hospital for risk analysis and model building and 89 surgically treated ASD at 2 other our hospitals for model validation. OUTCOME MEASURES: HRQoL measures and surgical complications. METHODS: We analyzed demographic and medical data, including complications, for 151 adults with ASD who underwent surgery at our hospital and were followed for at least 2years. Each surgical risk factor identified by univariate analyses was assigned a value based on its odds ratio, and the values of all risk factors were summed to obtain a surgical risk score (range 0–20). We stratified risk scores into grades (A–D) and analyzed their correlations with complications. We validated the model using data from 89 patients who underwent ASD surgery at two other hospitals. RESULTS: Complications developed in 48% of the patients in the model-building cohort. Univariate analyses identified 10 demographic, physical, and surgical risk indicators, with odds ratios from 5.4 to 1.4, for complications. Our risk-grading system showed good calibration and discrimination in the validation cohort. The complication rate increased with and correlated well with the risk grade using receiver operating characteristic curves. CONCLUSIONS: This simple, ASD-specific model uses readily accessible indicators to predict a patient's risk of perioperative and postoperative complications and can help surgeons adjust treatment strategies for best outcomes in high-risk patients.

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Surgical Outcomes for Drop Body Syndrome in Adult Spinal Deformity

Yagi M., Fujita N., Okada E., Tsuji O., Nagoshi N., Yato Y., Asazuma T., Nakamura M., Matsumoto M., Watanabe K.

Spine （Spine）  44 （ 8 ） 571 - 578 2019年04月

ISSN  03622436

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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.3.

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