Faculty Profiles - NAKASHIMA Hiroaki

Patterns of sitting spinal alignment in non-ambulatory scoliosis patients with paraplegia: an observational study Reviewed

Ouchida, J; Nakashima, H; Ohara, T; Machino, M; Ito, S; Segi, N; Yamauchi, I; Imagama, S

EUROPEAN SPINE JOURNAL Vol. 34 ( 2 ) page： 556 - 564 2025.2

Language：English Publisher：European Spine Journal

Purpose: To classify sagittal spinopelvic alignment patterns of non-ambulatory scoliosis patients with paraplegia based on lateral sitting radiographs and explore their relation to clinical background and physical function. Methods: We reviewed non-ambulatory scoliosis patients with paraplegia, excluding those with prior spinal surgery from a single-center database. Alignment patterns in sitting postures were classified into slump sitting (SS) and erect sitting (ES) based on the most posterior edge of the spine's location on lateral sitting radiographs. Radiographical spinopelvic sagittal alignment, demographics, and physical functions were analyzed. Clinical scoring for physical functions included Hoffer’s ambulator classification, Hoffer’s modified sitting classification, and the Modified Ashworth Score (MAS) for the severity of spasticity in the lower extremities. Percentages of patients without spasticity, with MAS of 0 indicating "no spasticity." were also compared between the two alignment patterns. Results: Of 172 patients screened, 86 met inclusion criteria, revealing two distinct alignment patterns: SS showed greater thoracic kyphosis, smaller lumbar lordosis, pelvic retroversion, and hip hyperflexion compared to ES. No significant differences in demographic data or curve patterns were observed between groups. The SS group had a significantly higher percentage of patients without spasticity compared to the ES group (39.2% vs. 14.3%, P = 0.016). Conclusion: Identified were two distinct sagittal alignment patterns in seated scoliosis patients with paraplegia, with potential influences from spasticity in the lower extremities. Recognizing these patterns can aid in assessing the function of sitting balance that includes the hip joint and in optimizing strategies for the treatment of scoliosis patients with paraplegia.

DOI： 10.1007/s00586-024-08584-0

Outcomes following instrumentation removal after posterior corrective fixation in adolescent idiopathic scoliosis Reviewed

Yamauchi, I; Nakashima, H; Ito, S; Segi, N; Ouchida, J; Morita, Y; Ode, Y; Nagatani, Y; Okada, Y; Tauchi, R; Ohara, T; Kawakami, N; Imagama, S

EUROPEAN SPINE JOURNAL Vol. 34 ( 2 ) page： 635 - 642 2025.2

Language：English Publisher：European Spine Journal

Purpose: To evaluate the complications and postoperative outcomes of implant removal after posterior fixation in adolescent idiopathic scoliosis. Methods: We retrospectively reviewed the data of patients who underwent implant removal after posterior corrective fixation for adolescent idiopathic scoliosis between 2002 and 2014. Complications were evaluated in the 116 patients who underwent implant removal at their choice. Radiological evaluations were performed and analyzed in 71 patients who were followed up for > 2 years after implant removal. Moreover, the patients were divided into two groups: those with increased thoracic kyphosis after implant removal and those without. Results: Overall, 14 of the 116 patients had complications. Two of the three patients with fractures required reoperation. Radiological examination revealed no significant difference in the scoliosis curvature in the coronal plane after implant removal. In the sagittal plane, the lowest instrumented vertebral tilt, cervical lordosis, T1 slope, T1–12 kyphosis angle, and T5–12 kyphosis angle were significantly increased. Moreover, patients with an increased T5–12 kyphosis angle after implant removal had greater pelvic incidence (PI) and sacral slope (SS) before implant removal. Conclusion: The prevalence of complications after implant removal in adolescent idiopathic scoliosis was 12.1%. Spinal alignment is more variable in the sagittal plane than in the coronal plane, and patients with increased thoracic kyphosis after implant removal have greater preoperative PI and SS. Sufficient preoperative explanation is necessary if a patient wishes to undergo implant removal.

DOI： 10.1007/s00586-024-08519-9

Difference of Disk Degeneration and Segmental Range of Motion due to Lumbar Disk Level among Age and Gender: 639 Asymptomatic Volunteer Data Open Access

Impact of diffuse idiopathic skeletal hyperostosis on quality of life and locomotive syndrome in community-dwelling older adults: the Yakumo study Reviewed Open Access

Ohshima, K; Nakashima, H; Segi, N; Ito, S; Ouchida, J; Takegami, Y; Ishizuka, S; Yamauchi, I; Hasegawa, Y; Murotani, K; Imagama, S

SCIENTIFIC REPORTS Vol. 15 ( 1 ) page： 3582 2025.1

Language：English Publisher：Scientific Reports

Diffuse idiopathic skeletal hyperostosis (DISH) is a common disease in older adults that causes extensive spinal ankylosis. However, its impact on quality of life (QOL) and locomotive syndrome (LS) remains unknown. Thus, we aimed to evaluate the DISH effect on QOL and LS in community-dwelling middle-aged and older adults. Data of community volunteers who attended a health checkup in 2018–2019 were assessed. A total of 455 subjects were included. Whole spine lateral radiographs were obtained to detect DISH according to the Resnik criteria. QOL was evaluated using SF-36 and EQ5D HUSV. LS was evaluated using the stand-up and two-step tests and GLFS-25. Multivariate regression analysis was performed, adjusting for sex, age, body mass index, and knee osteoarthritis. Additionally, a sex-stratified analysis was performed. DISH was detected in 83 (18.2%) participants. Multivariate analysis demonstrated that DISH was significantly associated with low EQ5D HSUV. Multivariate analysis in men demonstrated that DISH was associated with low PCS, low EQ5D HSUV, high LS stage. Multivariate analysis in women demonstrated that DISH was not associated with any QOL or LS. DISH may be associated with a poor QOL. Additionally, DISH is more common and produces a greater clinical impact in men than in women.

DOI： 10.1038/s41598-025-87878-9

Yamada Tomohiro, Nakashima Hiroaki, Machino Masaaki, Matsuyama Yukihiro, Kato Fumihiko, Yukawa Yasutsugu

Spine Surgery and Related Research Vol. 9 ( 1 ) page： 87 - 92 2025.1

Language：English Publisher：The Japanese Society for Spine Surgery and Related Research

Introduction: There is limited evidence between lumbar disk degeneration and normal lumbar segmental range of motions (SRMs), because previous studies were skewed by age and lacked large cohort of asymptomatic data. We aimed to characterize the normal lumbar SRMs according to age and gender and determine its association with disk degeneration.Methods: A total of 639 healthy Japanese volunteers (≥50 individuals of each decade of age from 20 to 79) without any symptom or morphological spinal abnormalities, who underwent lumbar radiograph and magnetic resonance image (MRI), were selected retrospectively. SRMs were evaluated by the flexion-extension radiographs taken in the recumbent position. Disk degenerations were assessed according to the Pfirrmann grade using MRI T2 imaging.Results: The mean SRMs became larger in the lower lumbar level. The range of the mean SRMs was smallest at L1-2 and largest at L4-5: 6 to 9 degrees at L1/2, to peaking at 11-14 degrees at L4/5 in male, and 6-8 degrees at L1/2, to peaking at 11-17 degrees at L4/5 in female. Lumbar disk degeneration progressed faster with age in the lower lumbar spine than in the upper lumbar level. SRM did not change depending on the severity of disk degeneration in upper lumbar spine, but significantly decreased with progressive disk degeneration in the lower lumbar spine.Conclusions: These findings could help to identify the normal lumbar SRMs that might be useful to evaluate the instability or inflexibility in the clinical situation. Furthermore, our results demonstrated the transition of the normative lumbar SRMs based on age, gender, and lumbar level.

DOI： 10.22603/ssrr.2024-0087

Trabecular Bone Remodeling after Lateral Lumbar Interbody Fusion: Indirect Findings for Stress Transmission between Vertebrae after Spinal Fusion Surgery Reviewed Open Access

Segi Naoki, Nakashima Hiroaki, Ito Sadayuki, Ouchida Jun, Oishi Ryotaro, Yamauchi Ippei, Miyairi Yuichi, Morita Yoshinori, Tsushima Mikito, Tomita Hiroyuki, Morishita Kazuaki, Ohshima Kazuma, Kanemura Tokumi, Imagama Shiro

Spine Surgery and Related Research Vol. 9 ( 1 ) page： 51 - 60 2025.1

Language：English Publisher：The Japanese Society for Spine Surgery and Related Research

Introduction: After posterior lumbar interbody fusion (PLIF), trabecular bone remodeling (TBR) occurs in the vertebral body. This study aimed to investigate whether imaging findings obtained with PLIF are applicable to lateral lumbar interbody fusion (LLIF).Methods: A total of 53 cases who underwent one- or two-level LLIF with polyether ether ketone cage and posterior spinal fixation/fusion (PSF) were retrospectively included in this study. TBR, vertebral endplate cyst (VEC), facet union, and pseudarthrosis were investigated on computed tomography (CT) images at 3 months, 1 year, and 2 years postoperatively. Of the 53 patients, 36 (68%) who underwent CT examination at approximately 5 years postoperatively were subanalyzed.Results: TBR was commonly observed anterior to the cage on CT sagittal images. The TBR-positive rate was 21%, 67%, and 73% at 3 months, 1 year, and 2 years postoperatively, respectively. The 3-month TBR-positive segments showed significantly less VEC (0% vs. 29%, P=0.029) at 1 year postoperatively. The 1-year TBR-positive segments showed a significantly higher facet union rate (83% vs. 57%, P=0.019) and less pseudoarthrosis (0% vs. 13%, P=0.041) at 2 years postoperatively. At 5 years postoperatively, 50% of the 2-year TBR-positive segments turned negative with solid intervertebral bony fusion.Conclusions: TBR-positive segments had significantly lower future VEC positivity, higher future facet union rates, and lower future pseudarthrosis rates. In LLIF-PSF, TBR suggests the establishment of intervertebral stability and allows consideration of intervertebral biomechanics.

DOI： 10.22603/ssrr.2024-0054

特集びまん性特発性骨増殖症(DISH)に対する治療の現状 DISHの総論と疫学 Reviewed

中島宏彰, 伊藤定之, 世木直喜, 大内田隼, 山内一平, 都島幹人, 今釜史郎

脊椎脊髄ジャーナル Vol. 38 ( 2 ) page： 56 - 60 2025.1

Effectiveness of Intraoperative Neurophysiological Spinal Cord Monitoring in Lumbosacral Spine Surgery: Analysis of 6,196 Patients from Spinal Cord Monitoring Committee of the Japanese Society for Spine Surgery and Related Research Reviewed Open Access

Takahashi Masahito, Imagama Shiro, Shigematsu Hideki, Funaba Masahiro, Ushirozako Hiroki, Nakanishi Kazuyoshi, Machino Masaaki, Taniguchi Shinichirou, Fujiwara Yasushi, Kobayashi Kazuyoshi, Yamamoto Naoya, Yamada Kei, Kanchiku Tsukasa, Iwasaki Hiroshi, Wada Kanichiro, Tadokoro Nobuaki, Ando Kei, Yasuda Akimasa, Hashimoto Jun, Morito Shinji, Kurosu Kenta, Nakashima Hiroaki, Segi Naoki, Arakawa Yasuo, Takatani Tsunenori, Kawabata Shigenori, Ando Muneharu, Matsuyama Yukihiro, Takeshita Katsushi, Yoshida Go

Journal of Spine Research Vol. 16 ( 1 ) page： 9 - 16 2025.1

Language：Japanese Publisher：The Japanese Society for Spine Surgery and Related Research

Introduction: In high-risk surgeries, those involving pathologies such as ossification of the posterior longitudinal ligament in the spine, spinal cord tumors, and spinal deformities, utilization of intraoperative neurophysiological monitoring (IONM) has been reported to be beneficial. However, efficacy of IONM for lumbosacral spinal surgery remains debated. Therefore, this study aimed to evaluate the efficacy of IONM in lumbosacral spinal surgeries in comparison with its use in cervical and/or thoracic spine surgeries.Methods: This was a multi-institutional prospective cohort study. The patients underwent spinal surgery with intraoperative neurophysiological monitoring in the hospitals of the Spinal Cord Monitoring Committee of the Japanese Society for Spine Surgery and Related Research. Patients were divided into two groups at the surgical level: 'cervical and/or thoracic' and 'lumbar and/or sacral'. Primary endpoints were sensitivity, specificity, positive and negative predictive values (PPV and NPV), and positive and negative likelihood ratios (PLR and NLR), and secondary endpoints were the incidence of postoperative motor palsy and the cutoff value of the rate of decrease of Tc-MEP amplitude in lumbar and/or sacral surgery.Results: The number of patients with cervical and/or thoracic surgery were 4,765, and those with lumbar and/or sacral surgery were 1,431. Furthermore, the sensitivity, specificity, PPV, NPV, PLR, and NLR were 77.6, 90.1, 21.1, 99.2, 7.9, and 0.2 in cervical and/or thoracic surgery, and 60.7, 95.9, 23.0, 99.2, 14.8, and 0.4 in lumbar and/or sacral surgery respectively. Specificity and PLR for lumbar and/or sacral surgery were significantly higher. Incidence of postoperative motor palsy was 3.1% (152/4,765) in the cervical and/or thoracic surgery group and 1.9% (27/1,431) in the lumbar and/or sacral surgery group. Cutoff value of the rate of Tc-MEP amplitude was 30%, with a 70% decrease compared to the baseline, and the sensitivity and specificity were 64.7% and 87.5%, respectively. The AUC was 0.69.Conclusions: Considering the substantially high specificity and PLR observed in lumbar and/or sacral surgeries, IONM can be considered effective within the context of lumbosacral spinal surgery.

DOI： 10.34371/jspineres.2023-0031

A nationwide multicenter study of the cost effectiveness of fi ve leading drugs for pharmacological management of cervicobrachial symptoms Reviewed

Wakao, N; Furuya, T; Yoshii, T; Arima, H; Yamato, Y; Nakashima, H; Imagama, S; Imajo, Y; Miyamoto, H; Inoue, G; Miyagi, M; Kanbara, S; Iizuka, Y; Chikuda, H; Watanabe, K; Kobayashi, K; Tsushima, M; Miyazaki, M; Yagi, M; Suzuki, S; Takahata, M; Hongo, M; Koda, M; Nagata, K; Mori, K; Suzuki, A; Kaito, T; Murotani, K; Miyakoshi, N; Hashizume, H; Matsuyama, Y; Kawakami, M; Haro, H

JOURNAL OF ORTHOPAEDIC SCIENCE Vol. 30 ( 1 ) page： 18 - 24 2025.1

Language：English Publisher：Journal of Orthopaedic Science

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.

DOI： 10.1016/j.jos.2023.12.004

Does Somatosensory-Evoked Potential Simultaneously Decrease with Transcranial Motor-Evoked Potential Alarm? A Multicenter Study by the Monitoring Committee of the Japanese Society for Spine Surgery and Related Research Reviewed Open Access

Trabecular Bone Remodeling after Posterior Lumbar Interbody Fusion: Comparison of the Osseointegration in Three-Dimensional Porous Titanium Cages and Polyether-Ether-Ketone Cages Reviewed Open Access

Segi, N; Nakashima, H; Ito, S; Ouchida, J; Oishi, R; Yamauchi, I; Miyairi, Y; Morita, Y; Matsumoto, T; Kanbara, S; Ito, K; Imagama, S

GLOBAL SPINE JOURNAL Vol. 15 ( 1 ) page： 66 - 75 2025.1

Language：English Publisher：Global Spine Journal

Study Design: Retrospective cohort study. Objectives: Imaging changes in the vertebral body after posterior lumbar interbody fusion (PLIF) are determined to be trabecular bone remodeling (TBR). This study aimed to investigate the influence of cage materials on TBR and segment stabilization in PLIF by studying image changes. Methods: This was a retrospective study reviewing 101 cases who underwent one-level PLIF with three-dimensional porous titanium (3DTi) cages (53 patients) or polyether-ether-ketone (PEEK) cages (48 patients). Computed tomography images obtained 3 months, 1 year, and 2 years postoperatively were examined for TBR, vertebral endplate cyst formation as an instability sign, cage subsidence, and clear zone around pedicle screw (CZPS). Results: No significant differences in the TBR-positivity rates were observed between the two cages at 3 months, 1 year, and 2 years postoperatively. However, all 3DTi cage segments that were TBR-positive at 3 months postoperatively showed no CZPS and fewer final instability segments than the TBR-negative segments (0% vs 9%). In contrast, although the PEEK cage segments that were TBR-positive at 3 months postoperatively were not associated with future segmental stabilization, those that were TBR-positive at 1 year postoperatively had fewer final instability segments than the TBR-negative segments (0% vs 33%). Conclusions: The 3DTi cage segments with TBR 3 months postoperatively showed significant final segmental stabilization, whereas TBR at 1 year rather than 3 months postoperatively was useful in determining final segmental stabilization for the PEEK cage segments. The timing of TBR, a new osseointegration assessment, were associated with the cage material.

DOI： 10.1177/21925682241255686

Characteristics of Poor Recordability of Intraoperative Neurophysiological Monitoring during Metastatic Spinal Tumor Surgery: A Multicenter Study Reviewed Open Access

Segi Naoki, Nakashima Hiroaki, Funaba Masahiro, Hashimoto Jun, Kawabata Shigenori, Takahashi Masahito, Yoshida Go, Ushirozako Hiroki, Kurosu Kenta, Shigematsu Hideki, Takatani Tsunenori, Morito Shinji, Yamada Kei, Iwasaki Hiroshi, Fujiwara Yasushi, Yasuda Akimasa, Ando Muneharu, Taniguchi Shinichirou, Wada Kanichiro, Tadokoro Nobuaki, Kobayashi Kazuyoshi, Yamamoto Naoya, Nakanishi Kazuyoshi, Kanchiku Tsukasa, Takeshita Katsushi, Matsuyama Yukihiro, Imagama Shiro

Spine Surgery and Related Research Vol. 9 ( 2 ) page： 164 - 172 2025

Language：English Publisher：The Japanese Society for Spine Surgery and Related Research

Introduction: The objective of this study is to investigate the poor recordability characteristics of intraoperative neurophysiological monitoring (IONM) for metastatic spinal tumors, focusing on tumor status or preoperative muscle weakness.Methods: A total of 132 patients (age 65.3±11.8 years; 82 men) with or without preoperative lower extremity muscle weakness were included in this study. The patients' background characteristics, the presence and degree of pre- and postoperative muscle weakness, and the IONM outcome, including the availability of transcranial motor evoked potential (Tc-MEP) recording and the occurrence of Tc-MEP alarms, were investigated. The data between the groups with and without preoperative muscle weakness were compared. Logistic regression analysis was performed to identify the risk factors for unrecordable Tc-MEP.Results: Sixty-seven patients with muscle weakness had significantly more unrecordable Tc-MEP (19% vs. 5%, p=0.009) than the 65 patients without muscle weakness. The highest percentage of recordable Tc-MEP in the group with muscle weakness was noted in the plantar muscle (72%). Multivariate analysis identified manual muscle test (MMT) score of ≤3 (odds ratio [OR] 4.529) and ventral spinal cord compression by metastatic tumor (OR 3.924) as independent significant factors for unrecordable Tc-MEP.Conclusions: IONM for metastatic spinal cord tumors with muscle weakness had a high rate of unrecordable Tc-MEP. Additionally, Tc-MEP may not be detectable in cases of ventral spinal cord compression by a tumor; therefore, preoperative imaging should be thoroughly evaluated.

DOI： 10.22603/ssrr.2024-0260

Shigematsu Hideki, Yoshida Go, Ushirozako Hiroki, Kurosu Kenta, Tadokoro Nobuaki, Funaba Masahiro, Kawabata Shigenori, Hashimoto Jun, Ando Muneharu, Taniguchi Shinichirou, Takahashi Masahito, Segi Naoki, Nakashima Hiroaki, Imagama Shiro, Morito Shinji, Yamada Kei, Takatani Tsunenori, Kanchiku Tsukasa, Fujiwara Yasushi, Iwasaki Hiroshi, Wada Kanichiro, Yamamoto Naoya, Kobayashi Kazuyoshi, Yasuda Akimasa, Nakanishi Kazuyoshi, Tanaka Yasuhito, Matsuyama Yukihiro, Takeshita Katsushi

Spine Surgery and Related Research Vol. 9 ( 2 ) page： 173 - 178 2025

Language：English Publisher：The Japanese Society for Spine Surgery and Related Research

Introduction: Multimodal intraoperative neurophysiological monitoring (IONM) -such as monitoring muscle-evoked potentials after transcranial electrical stimulation (Tc-MEP) with somatosensory-evoked potential (SEP) after electrical stimulation of the peripheral nerve-is recommended in spine surgeries to prevent iatrogenic neurological complications. However, the effect of using Tc-MEP with SEP to protect against neurological complications, particularly motor function, remains unknown. In clinical settings, changes due to Tc-MEP meeting the alarm points must be a potential neurological injury. This retrospective study, focusing on true-positive (TP) cases, aimed to clarify the change in the SEP waveform simultaneously with the Tc-MEP alarm.Methods: We included 68 patients with TP who had Tc-MEP changes and new postoperative motor weakness at more than one level of the manual muscle test after surgery. We compared the cases based on the category of spine surgery and paralysis type. We evaluated sex, age at spine surgery (high- or non high-risk), and paralysis type (segmental, long tract, or both). We defined the alarm points as follows: >70% decrease in Tc-MEP wave amplitudes, >50% decrease in wave amplitudes, or 10% extension of SEP latency. Next, we evaluated the SEP wave changes with a Tc-MEP alarm.Results: All patients showed progressive motor weakness after surgery, and 21 patients (31%) showed SEP changes at the same time as the Tc-MEP alarm. There were no statistically significant differences in the ratio of SEP change between the two groups according to the spine surgery category or among the three groups according to the paralysis type.Conclusions: Multimodal IONM is an important tool. However, the SEP changes do not necessarily appear immediately after the Tc-MEP alarm. Spine surgeons should appropriately treat Tc-MEP alarms to preserve motor function, regardless of SEP changes.

DOI： 10.22603/ssrr.2024-0229

Preoperative Planning for Cervical Pedicle Screw Placement: Identifying Key Morphological Parameters Open Access

Okada Yuya, Nakashima Hiroaki, Ito Sadayuki, Segi Naoki, Ouchida Jun, Urasaki Tetsuya, Imagama Shiro

Spine Surgery and Related Research Vol. 9 ( 3 ) page： 313 - 320 2025

Language：English Publisher：The Japanese Society for Spine Surgery and Related Research

Introduction: Cervical pedicle screw (CPS) placement is crucial for posterior cervical fusion surgery due to its strong fixation ability. However, CPS insertion is associated with risks, including screw perforation, which can lead to complications such as vertebral artery injury and neurological deficits. Although previous studies have explored some morphological factors affecting CPS placement, comprehensive data on specific parameters contributing to perforation remains limited. This study aimed to investigate cervical vertebrae features associated with CPS perforation and established threshold values for improved preoperative planning.Methods: A retrospective analysis of 36 patients who underwent posterior cervical fusion surgery with CPS placement was conducted using preoperative computed tomography (CT) -based navigation. Cases with CPS insertion at C1 or C2 were excluded. The key morphological parameters-optimal screw trajectory angle, pedicle diameter, and distance from the entry point to the pedicle isthmus (DEP) -were measured on preoperative CT images. CPS placement accuracy was assessed postoperatively using Neo's classification. The receiver operating characteristic (ROC) curve analysis determined the cutoff values for predicting CPS perforation.Results: Among the 102 CPSs placed from C3 to C7, the overall perforation rate was 25.5%. C3 had the highest perforation rate (45.5%), whereas C7 had the lowest (3.1%). The vertebrae with CPS perforation exhibited a significantly larger optimal screw trajectory angle (45.5° vs. 38.0°, p<0.001), smaller pedicle diameter (4.2 mm vs. 5.2 mm, p<0.001), and longer DEP (13.2 mm vs. 11.9 mm, p=0.002). The ROC analysis identified the following cutoff values: 44.0° for the optimal angle, 4.35 mm for the pedicle diameter, and 12.7 mm for the DEP. These morphological parameters strongly predicted the risk of CPS perforation.Conclusions: Establishing key morphological thresholds enhances preoperative planning for CPS placement, improves accuracy and patient safety, and minimizes complications.

DOI： 10.22603/ssrr.2024-0243

Impact of Nutritional Risk on Complications and Recovery in the Older People: A Geriatric Nutritional Risk Index-Based Study Reviewed Open Access

Ode Yukihito, Segi Naoki, Ito Sadayuki, Ouchida Jun, Yamauchi Ippei, Nagatani Yasuhiro, Okada Yuya, Takeichi Yosuke, Kagami Yujiro, Morishita Kazuaki, Oishi Ryotaro, Miyairi Yuichi, Morita Yoshinori, Tachi Hiroto, Ohshima Kazuma, Oyama Hiroki, Ogura Keisuke, Shinjo Ryuichi, Ohara Tetsuya, Tsuji Taichi, Kanemura Tokumi, Imagama Shiro, Nakashima Hiroaki

Spine Surgery and Related Research Vol. advpub ( 0 ) 2025

Language：English Publisher：The Japanese Society for Spine Surgery and Related Research

Introduction: The geriatric nutritional risk index (GNRI) has emerged as a useful predictor of surgical risk and postoperative outcomes. This study aimed to explore the utility of GNRI as a semiquantitative tool for predicting systemic and local complications after multilevel thoracolumbar fusion surgery in older patients and to evaluate the broader implications of nutritional status on postoperative recovery and independence.Methods: This multicenter study included 249 patients aged 65 years or older who underwent thoracolumbar fusion of at least four vertebrae. The nutrition-related risk grades were defined by the GNRI values, and the patients were divided into four groups: risk absent (GNRI > 98), low risk (GNRI 92 to ≤98), moderate risk (GNRI 82 to <92), and major risk (GNRI < 82). The occurrence of systemic complications, surgical site infection (SSI), length of stay in the hospital, place of discharge, and occurrence of proximal junctional kyphosis or failure (PJK/PJF) within 2 years after surgery were examined.Results: The risk-absent group consisted of 165 patients, the low-risk group of 40, the moderate-risk group of 36, and the major-risk group of eight. The incidence of any systemic complications (p = 0.016), PJK/PJF (p < 0.001), and hospital stay (p = 0.028) significantly increased with worsening GNRI. Furthermore, the number of patients who were discharged home significantly decreased as GNRI worsened (p < 0.001). SSI occurred most frequently in the risk-absent group (4.2%).Conclusions: The GNRI serves as a semiquantitative assessment tool that enables the identification of high-risk patients who may benefit from preoperative nutritional interventions.

DOI： 10.22603/ssrr.2025-0016

Comparison of anterior spinal bridging and sagittal spinal parameters in Diffuse Idiopathic Skeletal Hyperostosis and Axial Spondylitis: A multicenter study

Takahashi Takuya, Mori Kanji, Kobayashi Shigeto, Inoue Hisashi, Tada Kurisu, Tamura Naoto, Hirai Takashi, Matsukura Yu, Egawa Satoru, Tamura Satoshi, Nagoshi Narihito, Maki Satoshi, Katsumi Keiichi, Koda Masao, Murata Kazuma, Takeuchi Kazuhiro, Nakashima Hiroaki, Imagama Shiro, Kawaguchi Yoshiharu, Yoshii Toshitaka

Spine Surgery and Related Research Vol. advpub ( 0 ) 2025

Language：English Publisher：The Japanese Society for Spine Surgery and Related Research

Introduction: To evaluate the differences in anterior spinal bridging and sagittal spinal parameters between patients with diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) using whole-spine computed tomography (CT).Methods: This retrospective study included patients with DISH (n = 111) and AS (n = 27). The number of anterior spinal bridges and sagittal spinal parameters was evaluated. The sagittal vertical axis (SVA) evaluated by whole-spine CT was defined as sup-SVA. Patients were further evaluated by matching their age and sex.Results: Anterior spinal bridging frequently occurred in the thoracic spine in DISH and AS. In AS, bridging occurred in the lumbar spine according to the number of anterior spinal bridges. Sup-SVA and T5-T12 thoracic kyphosis (TK) were significantly greater in AS, and lumbar lordosis (LL) was significantly smaller in AS. TK was greater according to the number of anterior spinal bridges in both DISH and AS. Sup-SVA in DISH was greater according to the number of anterior spinal bridges, especially in the thoracic spine, whereas it was greater according to the lumbar in AS. LL in AS was smaller according to the number of lumbar bridges. Sup-SVA in DISH correlated with TK, whereas it correlated with both TK and LL in AS.Conclusions: In patients with AS, the spine tends to bridge from the lumbar to the thoracic spine, causing kyphosis in the thoracolumbar spine. In patients with DISH, the spine tends to bridge from the thoracic spine, causing kyphosis in the thoracic spine. Thus, sup-SVA is greater in AS than in DISH.

DOI： 10.22603/ssrr.2024-0345

Characteristics and Clinical Outcomes of Transition from Conservative Therapy to Surgical Intervention in Older Patients with Cervical Spinal Cord Injury Without Major Bone Injury: A Nationwide Retrospective Study Reviewed

Yokogawa Noriaki, Sasagawa Takeshi, Hayashi Hiroyuki, Demura Satoru, Nakashima Hiroaki, Segi Naoki, Watanabe Kota, Nori Satoshi, Funayama Toru, Eto Fumihiko, Nakajima Hideaki, Furuya Takeo, Yunde Atsushi, Terashima Yoshinori, Hirota Ryosuke, Yamada Tomohiro, Hasegawa Tomohiko, Suzuki Hidenori, Imajo Yasuaki, Kawaguchi Kenichi, Haruta Yohei, Tonomura Hitoshi, Sakata Munehiro, Terai Hidetomi, Tamai Koji, Inoue Gen, Ikegami Shota, Akeda Koji, Nakanishi Kazuo, Uei Hiroshi, Funao Haruki, Oshima Yasushi, Yoshii Toshitaka, Hashimoto Ko, Iizuka Yoichi, Kiyasu Katsuhito, Ishihara Masayuki, Kaito Takashi, Okada Seiji, Imagama Shiro, Kato Satoshi

Spine Surgery and Related Research Vol. advpub ( 0 ) 2025

Language：English Publisher：The Japanese Society for Spine Surgery and Related Research

Background: Cervical spinal cord injury (CSCI) without major bone injury is increasing among older adults, particularly in aging societies like Japan. The optimal treatment strategies remain unclear, with conservative therapy often preferred, especially for older patients. However, surgery is frequently necessary due to poor improvement or progression of paralysis during conservative treatment. This study investigated the characteristics and outcomes of older patients with CSCI without major bone injury who transitioned from conservative treatment to surgery.Methods: This nationwide, retrospective study examined data from patients aged ≥65 years with CSCI without major bone injury. The patients were categorized into 3 groups: conservative treatment, planned surgery, and those who switched from conservative treatment to surgery. The study aimed to identify the risk factors for conservative therapy failure that necessitate surgical intervention and to compare the outcomes between patients who had planned surgery and those who required surgery after conservative management failed.Results: Among 615 patients, 422 (68.6%) received conservative treatment, 193 (31.4%) had planned surgery, and 116 (18.9%) transitioned from conservative to surgical treatment. Transition to surgery was mainly due to poor improvement or progression of neurological deficits. Significant risk factors for transitioning to surgery included younger age, presence of ossification of the posterior longitudinal ligament, and spinal cord signal changes on magnetic resonance imaging. Comparative analysis showed no significant differences in neurological outcomes between patients who had surgery as planned and those who required surgery after failed conservative treatment.Conclusions: A significant proportion of older patients with CSCI without major bone injury who were initially managed conservatively eventually required surgery due to insufficient neurological improvement. The outcomes of patients who transitioned to surgery were similar to those who had surgery as initially planned, indicating that careful monitoring of conservative treatment followed by surgery, if necessary, may be an effective approach.

DOI： 10.22603/ssrr.2024-0291

Multimodal Deep Learning-based Radiomics Approach for Predicting Surgical Outcomes in Patients with Cervical Ossification of the Posterior Longitudinal Ligament Reviewed

Maki, S; Furuya, T; Katsumi, K; Nakajima, H; Honjoh, K; Watanabe, S; Kaito, T; Takenaka, S; Kanie, Y; Iwasaki, M; Furuya, M; Inoue, G; Miyagi, M; Ikeda, S; Imagama, S; Nakashima, H; Ito, S; Takahashi, H; Kawaguchi, Y; Futakawa, H; Murata, K; Yoshii, T; Hirai, T; Koda, M; Ohtori, S; Yamazaki, M

SPINE Vol. 49 ( 22 ) page： 1561 - 1569 2024.11

Language：English Publisher：Spine

Study Design. A retrospective analysis. Objective. This research sought to develop a predictive model for surgical outcomes in patients with cervical ossification of the posterior longitudinal ligament (OPLL) using deep learning and machine learning (ML) techniques. Summary of Background Data. Determining surgical outcomes assists surgeons in communicating prognosis to patients and setting their expectations. Deep learning and ML are computational models that identify patterns from large data sets and make predictions. Methods. Of the 482 patients, 288 patients were included in the analysis. A minimal clinically important difference (MCID) was defined as gain in Japanese Orthopaedic Association (JOA) score of 2.5 points or more. The predictive model for MCID achievement at 1 year postsurgery was constructed using patient background, clinical symptoms, and preoperative imaging features (x-ray, CT, MRI) analyzed through LightGBM and deep learning with RadImagenet. Results. The median preoperative JOA score was 11.0 (IQR: 9.0-12.0), which significantly improved to 14.0 (IQR: 12.0-15.0) at 1 year after surgery (P < 0.001, Wilcoxon signed-rank test). The average improvement rate of the JOA score was 44.7%, and 60.1% of patients achieved the MCID. Our model exhibited an area under the receiver operating characteristic curve of 0.81 and the accuracy of 71.9% in predicting MCID at 1 year. Preoperative JOA score and certain preoperative imaging features were identified as the most significant factors in the predictive models. Conclusion. A predictive ML and deep learning model for surgical outcomes in OPLL patients is feasible, suggesting promising applications in spinal surgery.

DOI： 10.1097/BRS.0000000000005088

Prospective Registration Study for Establishing Minimal Clinically Important Differences in Patients Undergoing Surgery for Spinal Metastases Reviewed

Hirota, R; Oshigiri, T; Iesato, N; Emori, M; Teramoto, A; Shiratani, Y; Suzuki, A; Terai, H; Shimizu, T; Kakutani, K; Kanda, Y; Tominaga, H; Kawamura, I; Ishihara, M; Paku, M; Takahashi, Y; Funayama, T; Miura, K; Shirasawa, E; Inoue, H; Kimura, A; Iimura, T; Moridaira, H; Nakajima, H; Watanabe, S; Akeda, K; Takegami, N; Nakanishi, K; Sawada, H; Matsumoto, K; Funaba, M; Suzuki, H; Funao, H; Hirai, T; Otsuki, B; Kobayakawa, K; Uotani, K; Manabe, H; Tanishima, S; Hashimoto, K; Iwai, C; Yamabe, D; Hiyama, A; Seki, S; Goto, Y; Miyazaki, M; Watanabe, K; Nakamae, T; Kaito, T; Nakashima, H; Nagoshi, N; Kato, S; Imagama, S; Watanabe, K; Inoue, G; Furuya, T

SPINE Vol. 49 ( 22 ) page： 1539 - 1547 2024.11

Language：English Publisher：Spine

Study Design. Multicenter, prospective registry study. Objective. To clarify minimal clinically important differences (MCIDs) for surgical interventions for spinal metastases, thereby enhancing patient care by integrating quality of life assessments with clinical outcomes. Background. Despite its proven usefulness in degenerative spinal diseases and deformities, the MCID remains unexplored regarding surgery for spinal metastases. Patients and Methods. This study included 171 (out of 413) patients from the multicenter "Prospective Registration Study on Surgery for Metastatic Spinal Tumors"by the Japan Association of Spine Surgeons. These were evaluated preoperatively and at 6 months postoperatively using the Face Scale, EuroQol-5 Dimensions-5 Levels (EQ-5D-5L), including the Visual Analog Scale, and performance status. The MCIDs were calculated using an anchor-based method, classifying participants into the improved, unchanged, and deteriorated groups based on the Face Scale scores. Focusing on the improved and unchanged groups, the change in the EQ-5D-5L values from before to after treatment was analyzed, and the cutoff value with the highest sensitivity and specificity was determined as the MCID through receiver operating characteristic curve analysis. The validity of the MCIDs was evaluated using a distribution-based calculation method for patient-reported outcomes. Results. The improved, unchanged, and deteriorated groups comprised 121, 28, and 22 participants, respectively. The anchor-based MCIDs for the EQ-5D-5L index, EQ-Visual Analog Scale, and domains of mobility, self-care, usual activities, pain/discomfort, and anxiety/depression were 0.21, 15.50, 1.50, 0.50, 0.50, 0.50, and 0.50, respectively; the corresponding distribution-based MCIDs were 0.17, 15,99, 0.77, 0.80, 0.78, 0.60, and 0.70, respectively. Conclusion. We identified MCIDs for surgical treatment of spinal metastases, providing benchmarks for future clinical research. By retrospectively examining whether the MCIDs are achieved, factors favoring their achievement and risks affecting them can be explored. This could aid in decisions on surgical candidacy and patient counseling.

DOI： 10.1097/BRS.0000000000005062