Publications by authors named "Kazuyoshi Kobayashi"

223 Publications

Age-related degenerative changes and sex-specific differences in osseous anatomy and intervertebral disc height of the thoracolumbar spine.

J Clin Neurosci 2021 Aug 21;90:317-324. Epub 2021 Jun 21.

Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.

The aim of this study was to determine age-related changes and sex-specific differences in sagittal alignment, range of motion (ROM), and intervertebral disc height of the thoracolumbar spine in healthy subjects. Lateral neutral and flexion-extension radiographs of the thoracolumbar spine of 627 asymptomatic subjects (307 males and 320 females; average age, 49.6 ± 16.5 years) were evaluated. We included at least 50 males and 50 females in each decade of life between the 20s and the 70s. Intervertebral disc height from T10/T11 to L5/S1, local lordotic alignment, and ROM from T10-T11 to L5-S1 were measured. T10-L2 kyphosis and T12-S1 lordosis as well as flexion, extension, and total ROM were measured. T10-L2 kyphosis did not markedly change with age in subjects of either sex but a sudden increase was noted in the 70s females. T12-S1 lordosis increased with age in both sexes, except the 70s. Flexion, extension, and total ROM at T10-L2 and T12-S1 decreased with age in most subjects. The levels from L3-L4 to L5-S1 were conspicuous as mobile segments. Intervertebral disc height gradually increased from T10/T11 to L4/L5; the shortest was at T10/T11 and the longest at L3/L4 or L4/L5 in all subjects. Age-related decreases in intervertebral disc height were most prominent at L4/L5 in middle-aged and elderly individuals of both sexes. Normative values of sagittal alignment, ROM, and intervertebral disc height at each segmental level were established in both sexes and all age groups in healthy subjects.
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http://dx.doi.org/10.1016/j.jocn.2021.06.020DOI Listing
August 2021

Ossification of the posterior longitudinal ligament located on the concave side of the apex vertebra in adult spinal deformity.

Nagoya J Med Sci 2021 May;83(2):387-392

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.

A 48-year-old female patient presented with discomfort in the front of the chest. Whole spinal X-ray revealed a thoracic curve of 52°, and thoracic computed tomography (CT) myelography and magnetic resonance imaging (MRI) showed that ossification of the posterior longitudinal ligament (OPLL) on the concave side of the apex vertebra (T9) had highly compressed the spinal cord. Cervical MRI also showed that the C4-C5 intervertebral disc herniation mildly compressed the spinal nerve. In concomitant surgery, the patient underwent cervical laminoplasty, in which OPLL was removed by decompressive laminectomy and posterior correction surgery.In patients with adult spinal deformity (ASD), asymmetric mechanical stress at the apex vertebra can cause various abnormal conditions. Long-term local mechanical stress on the concave side of the apex vertebra might have affected OPLL formation in the present case. This is the first report of a surgical case for an ossification located on the concave side of the apex vertebra in a patient with ASD. Mechanical stress at the concave side of the apex vertebra was suspected to be a cause of formation of OPLL.
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http://dx.doi.org/10.18999/nagjms.83.2.387DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8236683PMC
May 2021

Efficacy of Intraoperative Neuromonitoring Using Transcranial Motor-Evoked Potentials for Degenerative Cervical Myelopathy: A Prospective Multicenter Study by the Monitoring Committee of the Japanese Society for Spine Surgery and Related Research.

Spine (Phila Pa 1976) 2021 Jul 1. Epub 2021 Jul 1.

Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan Department of Orthopedic Surgery, Yamaguchi Rosai Hospital, Yamaguchi, Japan Department of Orthopedic Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan; Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan Department of Orthopedic Surgery, Tokyo Medical and Dental University, Tokyo, Japan Department of Orthopedic Surgery, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan Department of Orthopedic Surgery, Kansai Medical University, Osaka, Japan Department of Orthopedic Surgery, Kurume University, Kurume, Japan Department of Orthopedic Surgery, Wakayama Medical University, Wakayama, Japan Department of Orthopedic Surgery, Kochi University, Kochi, Japan Department of Orthopedic Surgery, Kyorin University, Tokyo, Japan Department of Orthopedic Surgery, Hirosaki University, Hirosaki, Japan Department of Orthopedic Surgery, Tokyo Women's Medical University Medical Center East, Tokyo, Japan Department of Orthopedic Surgery, Nara Medical University, Nara, Japan Department of Orthopedic Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan Division of Central Clinical Laboratory, Nara Medical University, Nara, Japan Department of Orthopedic Surgery, Kubokawa Hospital, Kochi, Japan The Monitoring Committee of the Japanese Society for Spine Surgery and Related Research.

Study Design: A prospective multicenter observational study.

Objective: To elucidate the efficacy of transcranial motor-evoked potentials (Tc(E)-MEPs) in degenerative cervical myelopathy (DCM) surgery by comparing cervical spondylotic myelopathy (CSM) to cervical ossification of the posterior longitudinal ligament (OPLL) and investigate the timing of Tc(E)-MEPs alerts and types of interventions affecting surgical outcomes.

Summary Of Background Data: Although CSM and OPLL are the most commonly encountered diseases of DCM, the benefits of Tc(E)-MEPs for DCM remain unclear and comparisons of these two diseases have not yet been conducted.

Methods: We examined the results of Tc(E)-MEPs from 1176 DCM cases (840 CSM /336 OPLL) and compared patients background by disease, preoperative motor deficits, and the type of surgical procedure. We also assessed the efficacy of interventions based on Tc(E)-MEPs alerts. Tc(E)-MEPs alerts were defined as an amplitude reduction of more than 70% below the control waveform. Rescue cases were defined as those in which waveform recovery was achieved after interventions in response to alerts and no postoperative paralysis.

Results: Overall sensitivity was 57.1%, and sensitivity was higher with OPLL (71.4%) than with CSM (42.9%). The sensitivity of acute onset segmental palsy including C5 palsy was 40% (OPLL/CSM: 66.7%/0%) whereas that of lower limb palsy was 100%. The most common timing of Tc(E)-MEPs alerts was during decompression (63.16%), followed by screw insertion (15.79%). The overall rescue rate was 57.9% (OPLL/CSM: 58.3%/57.1%).

Conclusion: Since Tc(E)-MEPs are excellent for detecting long tract injuries, surgeons need to consider appropriate interventions in response to alerts. The detection of acute onset segmental palsy by Tc(E)-MEPs was partially possible with OPLL, but may still be difficult with CSM. The rescue rate was higher than 50% and appropriate interventions may have prevented postoperative neurological complications.Level of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000004156DOI Listing
July 2021

Impact of Neck and Shoulder Pain on Health-Related Quality of Life in a Middle-Aged Community-Living Population.

Biomed Res Int 2021 8;2021:6674264. Epub 2021 Jun 8.

Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Japan.

Purpose: Neck and shoulder pain (NSP) is very common in the general population. However, scarce information exists on the relationship between NSP and health-related quality of life (HRQOL) outcomes in this population. The present study described NSP prevalence and its impact on the HRQOL of middle-aged and older persons undergoing a routine medical checkup.

Methods: This study recruited 318 subjects (125 males and 193 females; average age, 63.4 years) in good health, collected underwent anthropometric measurements, physical function examinations, and blood testing. This study defined NSP as the presence of muscle tension, stiffness, pressure, or dull pain in areas between the neck and the arch of the scapular. Study subjects were divided into two groups (NSP (+) and NSP (-) groups). The subjects completed questions on the Medical Outcomes Study 36-item short-form health survey (SF-36) and the EuroQol 5-dimension, 5-level version (EQ-5D-5L) tool.

Results: Of the patients, 150 and 168 were NSP (+) and NSP (-), respectively. The NSP complaint rate was 47.2%. The NSP (+) group had younger and more female participants than the NSP (-) group. In the multivariate regression analysis, the NSP (+) group had lower physical QOL based on the SF-36 physical component summary (odds ratio (OR), 2.45) and lower mental QOL based on the SF-36 mental component summary (OR, 2.05). Overall, the NSP (+) group had a higher risk of having low QOL scores (EQ-5D-5L index; OR, 1.76).

Conclusions: The NSP (+) rate in healthy middle-aged and older persons was 47.2%. Furthermore, NSP (+) status was directly related poor HRQOL. NSP is a predictor of suboptimal physical and mental QOL. Therefore, NSP prevention or intervention for NSP may improve middle-aged and older adults' QOL.
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http://dx.doi.org/10.1155/2021/6674264DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8208860PMC
June 2021

Human Nonmercaptalbumin Is a New Biomarker of Motor Function.

J Clin Med 2021 Jun 2;10(11). Epub 2021 Jun 2.

Department of Orthopaedic Surgery, Graduate School of Medicine, Nagoya University, Nagoya 466-8560, Japan.

The ratio of human nonmercaptalbumin (HNA) and reduced albumin (HMA) may be a new marker for oxidative stress. Locomotive syndrome (LS) is reduced mobility due to impairment of locomotive organs. We investigated whether the HNA/HMA ratio could be a new biomarker of LS. This study included 306 subjects (mean age 64.24 ± 10.4 years) who underwent LS tests, grip strength, walking speed, and tests for HNA and HMA. Oxidative stress was measured by the ratio of HMA (f(HMA) = (HMA/(HMA + HNA) × 100)), and the subjects were divided into normal (N group; f[HMA] ≥ 70%) and low (L group; f[HMA] < 70%) groups. There were 124 non-elderly (<65 years) and 182 elderly subjects (≥65 years). There were no significant differences in LS, grip strength, and walking speed between the L and N groups in the non-elderly subjects. However, significant differences were found in the elderly subjects. In logistic regression analysis, there was an association between f(HMA) and the LS severity at older ages. LS in the elderly is associated with a decline in HMA and, thus, an increase in oxidative stress. Thus, f(HMA) is a new biomarker of LS.
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http://dx.doi.org/10.3390/jcm10112464DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8199584PMC
June 2021

A Longitudinal Study of Lumbar Sagittal Change in Middle-Aged Healthy Volunteers.

Spine Surg Relat Res 2021 23;5(3):160-164. Epub 2020 Sep 23.

Department of Orthopedic Surgery, Nagoya University Hospital, Graduate School of Medicine, Aichi, Japan.

Introduction: Recent research has shown that spinal sagittal alignment plays a critical role in health-related quality of life. However, most of these studies were cross-sectional in nature, and longitudinal studies of lumbar lordosis (LL) in healthy subjects were few. This study aims to evaluate the change in lumbar sagittal parameters during a 10-year period.

Methods: The study population included 45 individuals (mean age, 65.7 years; male, n=20; female, n=25) who underwent sagittal lumbar radiography and a basic health checkup during a 10-year period. The radiologic parameters were LL, disc angle, sacral slope angle (SS), and pelvic incidence (PI). The change of LL during the 10-year period was defined as ΔLL. The subjects were divided into the LL maintenance group (n=33) and the LL non-maintenance group (n=12) based on their LL values.

Results: The radiologic baseline/final parameters were as follows: LL, 45/34 degrees (P<0.001); L1/L2 disc angle, 4.5/2.5 degrees; L2/L3 disc angle, 5.5/2.7 degrees; L3/L4 disc angle, 6.2/4.2 degrees; L4/L5 disc angle, 8.1/5.1 degrees; L5/S disc angle, 14.2/12.2 degrees; and SS, 32.0/32.1 degrees. The mean PI (50.5 degrees) was tended to be associated with the final LL (R=0.31, P=0.044) and was correlated with the ΔLL (R=0.43, P<0.01). The data of the LL maintenance/non-maintenance groups were as follows: age, 65.0/67.0; primary LL, 43.2/50.2 degrees (P<0.05); final LL, 36.2/27.8 degrees (P<0.05); and PI, 52.8/43.8 degrees (P<0.01).

Conclusions: During the 10-year study period, the LL in middle-aged and elderly volunteers decreased by 11 degrees. The factor of maintenance of LL was PI.
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http://dx.doi.org/10.22603/ssrr.2020-0123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8208952PMC
September 2020

Characteristics of cases with and without calcification in spinal meningiomas.

J Clin Neurosci 2021 Jul 29;89:20-25. Epub 2021 Apr 29.

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan.

Purpose: To quantify calcification in spinal meningiomas using Hounsfield unit (HU) values on CT, and to analyze the characteristics of cases with and without calcification and with different histologic subtypes.

Methods: The subjects were 53 patients who underwent surgical resection of spinal meningioma between January 1999 and December 2019. Clinical and surgical data were collected, and all patients were examined neurologically preoperatively and at final follow-up using the modified McCormick scale and the American Spinal Injury Association scale. Calcification was quantified on CT of the spine prior to surgery. A HU value >60 was considered to indicate calcification.

Results: The 53 patients (11 males, 42 females) were aged 62.4 ± 14.3 (range 19 to 91) years at surgery, and had a symptom duration of 10.8 ± 9.0 (1-36) months. The histological type was meningothelial in 35 cases, psammomatous in 13, and others in 5. The mean tumor volume was 1166 ± 350 (593-2176) mm, and the mean HU value was 212.2 ± 192.8 (43-648). Forty cases (75%) had calcification (HU value > 60). HU values were significantly related to duration of symptoms (R = 0.590, p < 0.05) and significantly higher in psammomatous cases (p < 0.05). Cases with calcification had longer operative times and greater blood loss, and a significantly lower rate of neurological improvement.

Conclusion: CT was effective for detecting calcification based on HU values. Detection of a HU value > 60 in spinal meningioma may be useful to narrow the differential diagnosis, evaluate the difficulty of resection, and improve intraoperative management, all of which may improve outcomes.
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http://dx.doi.org/10.1016/j.jocn.2021.04.019DOI Listing
July 2021

Lumbar Thecal Sac Dimensions and Axial Spinal Cord Areas on Magnetic Resosnace Imaging in 626 Healthy Subjects.

Spine (Phila Pa 1976) 2021 Jun 10. Epub 2021 Jun 10.

Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Aichi, Japan Department of Orthopedics Surgery, Chubu Rosai Hospital, Minato-ku, Nagoya, Japan.

Study Design: A cross-sectional study.

Objective: The aim of this study was to investigate the lumbar thecal sac dimensions and spinal cord area on magnetic resonance (MR) imaging in healthy volunteers.

Summary Of Background Data: There are few reports regarding lumbar spine MRI in healthy subjects, and the difference in spinal canal dimensions by age remains unclear.

Methods: A total of 629 healthy volunteers were enrolled, including ≥50 males, females, and subjects in each of the 20s to 70s age decades. The anteroposterior and transverse diameters of the thecal sac and axial areas of the thecal sac and spinal cord were measured at the disc levels on T2-weighted axial MR images. The anteroposterior-to-transverse ratio of the thecal sac (APTR) was calculated.

Results: The thecal sac area from T12/L1 to L4/5 was reduced in older age group, but there was no significant difference in L5/S1. The thecal sac area was significantly reduced in older age group: 89.9%, 86.0%, 84.6%, 80.3% at T12/L1, L1/2, L2/3, and L3/4, respectively, and 79.9% at L4/5 in subjects in their 70 s relative to that in subjects in their 20 s. The APTR was significantly reduced in older age group from T11/12 to L2/L3 in males and at T10/11, L3/4 and from T11/12 to L2/3 in females. Narrow thecal sac areas <80 mm2 were found in 10 subjects. The spinal cord area was significantly reduced in older age group at T10/11 in males and at T9/10, T10/11, and T11/12 in females. The area was 92.0% at T10/11 in subjects in their 70s relative to the area of subjects in their 20s.

Conclusion: The thecal sac area was reduced in older age group from T12/L1 to L4/5, and the thecal sac area was reduced in the anteroposterior and all directions in the upper and lower lumbar area in age group, respectively. Approximately, 3.0% of healthy population in their 50s or older will have severe asymptomatic stenosis.Level of Evidence: 2.
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http://dx.doi.org/10.1097/BRS.0000000000004143DOI Listing
June 2021

Normative Magnetic Resonance Imaging Data of Age-Related Degenerative Changes in Cervical Disc Morphology.

World Neurosurg 2021 Jun 16. Epub 2021 Jun 16.

Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Aichi, Nagoya, Aichi, Japan.

Objective: Few studies have examined a possible correlation between cervical disc degeneration and disc height. The aim of this study was to establish age-related changes and sex-specific differences of cervical disc height using magnetic resonance imaging (MRI) and to evaluate the relationship between degree of cervical disc degeneration and disc height in asymptomatic subjects.

Methods: We measured the intervertebral disc anteroposterior diameter and disc height in each disc level using MRI in 1211 relatively healthy volunteers (606 men and 605 women, mean age 49.5 years). We included at least 100 males and 100 females in each decade of life between the 20s and the 70s. Cervical disc degeneration was defined according to the modified Pfirrmann classification system, and disc index and intervertebral disc height narrowing ratio were evaluated on sagittal plane MRI.

Results: Intervertebral disc height decreased gradually with increasing age in both sexes. The grade of disc degeneration significantly increased with age in both sexes at every level. Mild disc degeneration was observed even in subjects their 20s. Disc degeneration occurred around the C5-C6 level. The average disc height decreased with aging after the 40s. Disc index and intervertebral disc height narrowing ratio decreased with a progression in the disc degeneration grade in both sexes.

Conclusions: This large-scale cross-sectional analysis of cervical spine MRI data in healthy subjects demonstrated that cervical disc height narrowing progresses with age. Cervical disc height narrowing is highly correlated with the progression of disc degeneration.
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http://dx.doi.org/10.1016/j.wneu.2021.05.123DOI Listing
June 2021

Clinical features and prognostic factors in spinal meningioma surgery from a multicenter study.

Sci Rep 2021 Jun 2;11(1):11630. Epub 2021 Jun 2.

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.

Meningiomas are benign tumors that are treated surgically. Local recurrence is likely if the dura is preserved, and en bloc tumor and dura resection (Simpson grade I) is recommended. In some cases the dura is cauterized and preserved after tumor resection (Simpson grade II). The purpose of this study was performed to analyze clinical features and prognostic factors associated with spinal meningioma, and to identify the most effective surgical treatment. The subjects were 116 patients (22 males, 94 females) with spinal meningioma who underwent surgery at seven NSG centers between 1998 and 2018. Clinical data were collected from the NSG database. Pre- and postoperative neurological status was defined using the modified McCormick scale. The patients had a mean age of 61.2 ± 14.8 years (range 19-91 years) and mean symptom duration of 11.3 ± 14.7 months (range 1-93 months). Complete resection was achieved in 108 cases (94%), including 29 Simpson grade I and 79 Simpson grade II resections. The mean follow-up period was 84.8 ± 52.7 months. At the last follow-up, neurological function had improved in 73 patients (63%), was stable in 34 (29%), and had worsened in 9 (8%). Eight patients had recurrence, and recurrence rates did not differ significantly between Simpson grades I and II in initial surgery. Kaplan-Meier analysis of recurrence-free survival showed that Simpson grade III or IV, male, and dural tail sign were significant factors associated with recurrence (P < 0.05). In conclusion, Simpson I resection is anatomically favorable for spinal meningiomas. Younger male patients with a dural tail and a high-grade tumor require close follow-up. The tumor location and feasibility of surgery can affect the surgical morbidity in Simpson I or II resection. All patients should be carefully monitored for long-term outcomes, and we recommend lifelong surveillance after surgery.
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http://dx.doi.org/10.1038/s41598-021-91225-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8172892PMC
June 2021

Effects of Preoperative Motor Status on Intraoperative Motor-evoked Potential Monitoring for High-risk Spinal Surgery: A Prospective Multicenter Study.

Spine (Phila Pa 1976) 2021 Jun;46(12):E694-E700

The Monitoring Committee of the Japanese Society for Spine Surgery and Related Research, Japan.

Study Design: Prospective multicenter observational study.

Objective: To evaluate transcranial motor-evoked potentials (Tc-MEPs) baseline characteristics of lower limb muscles and to determine the accuracy of Tc-MEPs monitoring based on preoperative motor status in surgery for high-risk spinal disease.

Summary Of Background Data: Neurological complications are potentially serious side effects in surgery for high-risk spine disease. Intraoperative spinal neuromonitoring (IONM) using Tc-MEPs waveforms can be used to identify neurologic deterioration, but cases with preoperative motor deficit tend to have poor waveform derivation.

Methods: IONM was performed using Tc-MEPs for 949 patients in high-risk spinal surgery. A total of 4454 muscles in the lower extremities were chosen for monitoring. The baseline Tc-MEPs was recorded immediately after exposure of the spine. The derivation rate was defined as muscles detected/muscles prepared for monitoring. A preoperative neurological grade was assigned using the manual muscle test (MMT) score.

Results: The 949 patients (mean age 52.5 ± 23.3 yrs, 409 males [43%]) had cervical, thoracic, thoracolumbar, and lumbar lesions at rates of 32%, 40%, 26%, and 13%, respectively. Preoperative severe motor deficit (MMT ≤3) was present in 105 patients (11%), and thoracic ossification of the posterior longitudinal ligament (OPLL) was the most common disease in these patients. There were 32 patients (3%) with no detectable waveform in any muscles, and these cases had mostly thoracic lesions. Baseline Tc-MEPs responses were obtained from 3653/4454 muscles (82%). Specificity was significantly lower in the severe motor deficit group. Distal muscles had a higher waveform derivation rate, and the abductor hallucis (AH) muscle had the highest derivation rate, including in cases with preoperative severe motor deficit.

Conclusion: In high-risk spinal surgery, Tc-MEPs collected with multi-channel monitoring had significantly lower specificity in cases with preoperative severe motor deficit. Distal muscles had a higher waveform derivation rate and the AH muscle had the highest rate, regardless of the severity of motor deficit preoperatively.Level of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003994DOI Listing
June 2021

Efficacy of Transcranial Motor Evoked Potential Monitoring During Intra- and Extramedullary Spinal Cord Tumor Surgery: A Prospective Multicenter Study of the Monitoring Committee of the Japanese Society for Spine Surgery and Related Research.

Global Spine J 2021 May 20:21925682211011443. Epub 2021 May 20.

Department of Orthopedic Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan.

Study Design: Multicenter prospective study.

Objectives: Although intramedullary spinal cord tumor (IMSCT) and extramedullary SCT (EMSCT) surgeries carry high risk of intraoperative motor deficits (MDs), the benefits of transcranial motor evoked potential (TcMEP) monitoring are well-accepted; however, comparisons have not yet been conducted. This study aimed to clarify the efficacy of TcMEP monitoring during IMSCT and EMSCT resection surgeries.

Methods: We prospectively reviewed TcMEP monitoring data of 81 consecutive IMSCT and 347 EMSCT patients. We compared the efficacy of interventions based on TcMEP alerts in the IMSCT and EMSCT groups. We defined our alert point as a TcMEP amplitude reduction of ≥70% from baseline.

Results: In the IMSCT group, TcMEP monitoring revealed 20 true-positive (25%), 8 rescue (10%; rescue rate 29%), 10 false-positive, a false-negative, and 41 true-negative patients, resulting in a sensitivity of 95% and a specificity of 80%. In the EMSCT group, TcMEP monitoring revealed 20 true-positive (6%), 24 rescue (7%; rescue rate 55%), 29 false-positive, 2 false-negative, and 263 true-negative patients, resulting in a sensitivity of 91% and specificity of 90%. The most common TcMEP alert timing was during tumor resection (96% vs. 91%), and suspension surgeries with or without intravenous steroid administration were performed as intervention techniques.

Conclusions: Postoperative MD rates in IMSCT and EMSCT surgeries using TcMEP monitoring were 25% and 6%, and rescue rates were 29% and 55%. We believe that the usage of TcMEP monitoring and appropriate intervention techniques during SCT surgeries might have predicted and prevented the occurrence of intraoperative MDs.
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http://dx.doi.org/10.1177/21925682211011443DOI Listing
May 2021

Association between Low Muscle Mass and Inflammatory Cytokines.

Biomed Res Int 2021 27;2021:5572742. Epub 2021 Apr 27.

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.

Sarcopenia is a multifaceted geriatric syndrome associated with the loss of muscle mass. We examined the relationship between low muscle mass and inflammatory cytokines in the context of aging. This study involved 299 participants (127 men and 172 women; mean age 63.3 ± 9.8 years) who underwent health checkups for body composition and inflammatory cytokine (TNF-alpha, IL-6, and MCP-1) levels. Muscle mass was determined using the skeletal muscle mass index. We divided the participants into the normal (N) and low muscle mass (L) groups and compared the levels of inflammatory cytokines in nonelderly (<65 years) and elderly (≥65 years) participants. Among the nonelderly subjects, C-reactive protein was significantly lower in the L group than in the N group ( < 0.05). However, there was no significant difference in the inflammatory cytokine levels between the groups. Among the elderly subjects, the TNF-alpha level was significantly lower in the L group than in the N group ( < 0.05), whereas there were no significant differences in the IL-6 and MCP-1 levels. Moreover, TNF-alpha was identified as a risk factor for the L group in the logistic regression analysis (Exp (B) 0.935, 95% CI: 0.876-0.997, = 0.04). Although a low TNF-alpha level is a risk factor for low muscle mass, inflammatory cytokine levels are not necessarily elevated in elderly individuals with the loss of muscle mass.
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http://dx.doi.org/10.1155/2021/5572742DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8099521PMC
May 2021

Characteristics of Tc-MEP Waveforms in Spine Surgery for Patients with Severe Obesity.

Spine (Phila Pa 1976) 2021 May 6. Epub 2021 May 6.

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan Department of Orthopedic Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan Department of Orthopedic Surgery, Kansai Medical University, Osaka, Japan Department of Orthopedic Surgery, Tokyo Medical and Dental University, Tokyo, Japan Department of Orthopedic Surgery, Kurume University School of Medicine, Kurume, Japan Department of Orthopedic Surgery, Yamaguchi Rosai Hospital, Yamaguchi, Japan Department of Orthopedic Surgery, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan Department of Orthopedic Surgery, Wakayama Medical University, Wakayama, Japan Department of Orthopedic Surgery, Nara Medical University, Nara, Japan Department of Orthopedic Surgery, Kochi University, Kochi, Japan Department of Orthopedic Surgery, Kyorin University, Tokyo, Japan Department of Orthopedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan Department of Orthopedic Surgery, Tokyo Women's Medical University Medical Center East, Tokyo, Japan Department of Orthopedic Surgery, Yamaguchi University, Yamaguchi, Japan Department of Orthopedic Surgery, National Defense Medical College Hospital, Saitama, Japan Division of Central Clinical Laboratory, Nara Medical University, Nara, Japan Department of Orthopedic Surgery, Kubokawa Hospital, Kochi, Japan.

Study Design: Prospective multicenter study.

Objective: To evaluate transcranial motor evoked potential (Tc-MEP) waveform monitoring in spinal surgery for patients with severe obesity.

Summary Of Background Data: Spine surgeries in obese patients are associated with increased morbidity and mortality. Intraoperative Tc-MEP monitoring can identify neurologic deterioration during surgery, but has not been examined for obese patients.

Methods: The subjects were 3560 patients who underwent Tc-MEP monitoring during spine surgery at 16 centers. Tc-MEPs were recorded from multiple muscles via needle or disc electrodes. A decrease in Tc-MEP amplitude of ≥70% from baseline was used as an alarm during surgery. Preoperative muscle weakness with manual muscle test (MMT) grade ≤4 was defined as a motor deficit, and a reduction of one or more MMT grade postoperatively was defined as deterioration.

Results: The 3560 patients (1698 males, 47.7%) had a mean age of 60.0 ± 20.3 years. Patients with body mass index >35 kg/m2 (n = 60, 1.7%) were defined as severely obese. Compared with all other patients (controls), the rates of preoperative motor deficit (41.0% vs. 29.6%, p < 0.05) and undetectable baseline waveforms in all muscles were significantly higher in the severely obese group (20.0% vs. 1.7%, p < 0.01). Postoperative motor deterioration did not differ significantly between the groups. The sensitivity and specificity of the alarm criterion for prediction of postoperative neurologic complications were 75.0% and 83.9% in severely obese patients and 76.4% and 89.6% in controls, with no significant difference between the groups.

Conclusion: Tc-MEPs can be used in spine surgery for severely obese cases to predict postoperative motor deficits, but the rate of undetectable waveforms is significantly higher in such cases. Use of a multichannel waveform approach or multiple modalities may facilitate safe completion of surgery. Waveforms should be carefully evaluated and an appropriate rescue procedure is required if the alarm criterion occurs.Level of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000004096DOI Listing
May 2021

Risk factors of non-union in Anderson-D'Alonzo type III odontoid fractures with conservative treatment.

J Orthop 2021 Mar-Apr;24:280-283. Epub 2021 Mar 29.

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.

Objective: The purpose of this study was retrospectively to analyze the risk factors for non-union in Anderson-D'Alonzo type III odontoid fractures with conservative treatment.

Methods: 25 patients with type III fractures were analyzed. Coronal and sagittal tilt as well as sagittal and lateral mass gaps were measured by using computed tomography.

Results: The non-union group had significantly higher age, greater coronal tilt and lateral mass gap. Especially, the lateral mass gap was >2 mm in all cases with non-union.

Conclusions: Higher age, coronal tilt, and lateral mass gap were significant risk factors for non-union.
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http://dx.doi.org/10.1016/j.jor.2021.03.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8049875PMC
March 2021

Bioelectrical Impedance Analysis and Manual Measurements of Neck Circumference Are Interchangeable, and Declining Neck Circumference Is Related to Presarcopenia.

Biomed Res Int 2021 29;2021:6622398. Epub 2021 Mar 29.

Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Japan.

Purpose: Preventive medicine is important in an aging society. Presarcopenia is the preliminary stage of sarcopenia. Recent advances in bioelectrical impedance analysis (BIA) devices have enabled automatic estimation of neck circumference (NC). However, the agreement between and interchangeability of NC measured manually and that calculated with BIA have not been evaluated. We performed these analyses in the context of health checkups and investigated their associations with presarcopenia.

Methods: We enrolled 318 participants who underwent anthropometric measurements, including NC measured manually and by BIA; assessment of physical function; and blood testing. We used Bland-Altman analysis to calculate the agreement between and interchangeability of NC measurements by BIA and by the manual method. We then statistically compared normal participants and those with presarcopenia. Using multivariable analysis, we subsequently investigated significant risk factors for presarcopenia. We defined presarcopenia according to the appendicular skeletal muscle index (aSMI; the ratio of arm and leg skeletal muscle mass to height).

Results: Bland-Altman analysis showed that bias (BIA-manual) was negative overall (-1.07), for male participants (-1.23), and for female participants (-0.96). This finding suggests that BIA measurement is an underestimate in comparison with manual measurement. NC measurement by BIA was found to be interchangeable with that by manual methods, inasmuch as the percentage error was less than 5% overall (4.38%), for male participants (3.81%), and for female participants (4.58%). Univariable analysis revealed that NC was significantly smaller in the participants with presarcopenia than in those without. Multivariable analysis, adjusted for confounding factors, revealed that a decrease in NC was significantly correlated with presarcopenia.

Conclusions: BIA measurements of NC are interchangeable within about 95% with manual measurements. The decrease in NC measured by BIA was significantly associated with presarcopenia in both genders. NC measurement can be used for early detection of presarcopenia.
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http://dx.doi.org/10.1155/2021/6622398DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8024069PMC
May 2021

Conservative treatment of spondylolysis involving exercise initiated early and sports activities resumed with a lumbar-sacral brace.

J Orthop Sci 2021 Apr 9. Epub 2021 Apr 9.

Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Japan.

Background: Conservative treatment including the use of a brace and cessation of sports activities is known to be effective in spondylolysis. However, there is some controversy regarding [1] the type of brace, and [2] the endpoint for bracing, and [3] the timing of resumption of sports activities. The aim of the current study was to investigate the appropriateness of early exercise and resumption of sports activities with a lumbar-sacral brace in very early- and early-stage lumbar spondylolysis.

Methods: This prospective cohort study enrolled 45 patients with very early- and early-stage lumbar spondylolysis. A lumbar-sacral brace, structured to be a hard brace in the back and a mesh brace in the front, was used. Isometric exercises/stretching was started immediately after the initial visit. The number of patients for whom bone fusion was fully achieved on CT and the disappearance of signal intensity change on MRI were investigated.

Results: In 12 cases of very early-stage spondylolysis, the average elapsed time until signal intensity disappearance as confirmed on MRI was 4.3 ± 1.6 months. Bony union on CT was confirmed in all cases. In 33 cases of early spondylolysis, signal intensity change disappeared on MRI within 5.2 ± 2.4 months. The rate of bony union was 94.3%, and the average period required to achieve bony union observable on CT was 3.7 ± 1.0 months.

Conclusions: Sufficient bony union can be achieved by conservative treatment with early exercise and a lumbar-sacral brace in cases of very early and early spondylolysis.
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http://dx.doi.org/10.1016/j.jos.2021.01.013DOI Listing
April 2021

Kinetic changes in the spinal cord occupation rate of dural sac in cervical spondylotic myelopathy.

J Orthop 2021 Mar-Apr;24:222-226. Epub 2021 Mar 11.

Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.

Objective: The study aimed to establish the spinal cord occupation rate of the dural sac during flexion and extension.

Methods: We measured the cross-sectional area of the dural sac and the spinal cord between C2/C3 and C7/T1 disc levels in 100 patients with cervical spondylotic myelopathy and 1211 asymptomatic subjects.

Results: The spinal cord occupation rate of the dural sac in the cross-sectional area was higher on extension than on flexion at the mid-lower cervical spine.

Conclusions: The spinal cord occupation rate of the dural sac in the cross-sectional area was highest at the C4/C5 and C5/C6 levels on extension.
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http://dx.doi.org/10.1016/j.jor.2021.03.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7973381PMC
March 2021

The dual presence of frailty and locomotive syndrome is associated with a greater decrease in the EQ-5D-5L index.

Nagoya J Med Sci 2021 Feb;83(1):159-167

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.

Japan's aging society is facing an increase in the prevalence of frailty and locomotive syndrome (LS) among older adults. To evaluate the association of these age-related declines on health-related quality of life (QOL) in Japan, we investigated this relationship among Japanese middle-aged and older adults who underwent general checkups and examined whether LS or frailty has a stronger association with the Japanese version of EuroQol's five-level EQ-5D (EQ-5D-5L) index. Participants were 231 middle-aged and older Japanese adults receiving routine health checkups. The study utilized the 25-item Geriatric Locomotive Function Scale, the Japanese version of the Cardiovascular Health Study, and the Japanese version of the EQ-5D-5L. Univariate and multivariate analyses were performed to examine how frailty and LS are related to the EQ-5D-5L index. Patients with both frailty (p = 0.003) and LS (p < 0.001) had a significantly lower EQ-5D-5L index. After adjusting for age, gender, and body mass index, LS was significantly associated with a decrease in the EQ-5D-5L index (p < 0.001), whereas frailty had no significant association with the EQ-5D-5L index (p = 0.052). Further analysis showed no significant decrease in the EQ-5D-5L index among those with frailty but no LS, and a significant decrease among those with frailty and LS. The results suggest that frailty and LS are associated with a decrease in the EQ-5D-5L index, but LS has a more pronounced effect. In evaluating frailty's effects on health-related QOL, we determined the importance of separately assessing frailty both with and without LS, even within the same frailty group.
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http://dx.doi.org/10.18999/nagjms.83.1.159DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7938103PMC
February 2021

Challenges for Joint Commission International accreditation: performance of orthopedic surgeons based on International Patient Safety Goals.

Nagoya J Med Sci 2021 Feb;83(1):87-92

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.

The Joint Commission International (JCI) is a US-based organization that accredits and certifies hospitals worldwide. Among the requirements for accreditation, the JCI emphasizes continuous quality improvement (CQI) with regard to international patient safety goals (IPSGs). Our university hospital treats about 26,000 hospitalized patients and 600,000 outpatients annually, and our goal is patient safety in compliance with IPSGs. The purpose of this study is to examine the activities of orthopedic surgeons in preparation for JCI accreditation, including clear identification of patients, preoperative timeout and marking to ensure correct surgery, timely approval of CT/MRI reports, care with pain management, prevention of infection, setting of quality indicators and daily monitoring, and teamwork. Examiners from the JCI visited our hospital to review medical records and documents, and to interview patients, nurses and doctors. There were 1270 evaluation items covering 16 fields, including reviews of IPSGs, patient evaluation and care, infection prevention and control, and governance and leadership. Most importantly, the efforts of all the medical staff in our hospital in obtaining the first JCI accreditation among national university hospitals in Japan have promoted the safety and quality of medical care from the perspective of the patient.
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http://dx.doi.org/10.18999/nagjms.83.1.87DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7938100PMC
February 2021

Differences in the prevalence of locomotive syndrome and osteoporosis in Japanese urban and rural regions: The Kashiwara and Yakumo studies.

Mod Rheumatol 2021 Mar 30:1-6. Epub 2021 Mar 30.

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.

Objectives: To clarify whether the prevalence of locomotive syndrome (LS) and osteoporosis differed according to region, gender, and physical functions in Japan.

Methods: Data were collected in Kashiwara City (urban region) and Yakumo Town (rural region). Totally, 208 participants from the urban region and 782 participants from the rural region were included in this study. LS was assessed using the 25-item Geriatric Locomotive Function Scale and osteoporosis was assessed using a quantitative ultrasound. Physical functions were measured using grip strength and the 3-m timed up-and-go test. Differences between urban and rural regions were investigated using standardized incidence ratio and multivariate analysis.

Results: The prevalence of LS and osteoporosis was 24.5% and 42.8% in the urban region and 10.9% and 28.8% in the rural region, respectively. The standardized incidence ratio of the urban region versus the rural region was 1.80 (95% confidence intervals [CI] = 1.35-2.39) for LS and 1.21 (95% CI = 1.32-2.43) for osteoporosis, showing that the prevalence of LS was significantly higher in the urban region. Multivariate analysis indicated that LS was significantly associated with the urban sample and timed up-and-go was significantly longer in the urban sample.

Conclusion: Regional differences may be considered when evaluating LS in health checkups. Understanding the results of this study may help reduce LS prevalence.
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http://dx.doi.org/10.1080/14397595.2021.1899890DOI Listing
March 2021

Postoperative Syrinx Shrinkage in Spinal Ependymoma of WHO Grade II.

Clin Spine Surg 2021 Mar;34(2):E100-E106

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Tsurumai-cho, Showa-ku, Nagoya.

Study Design: A retrospective study of preoperative and postoperative magnetic resonance imaging (MRI) findings in spinal ependymoma.

Objective: The goal of the study was to examine MRI features, including the syrinx component volume, after surgical resection of spinal ependymoma, and to relate these features to extent of resection and improvement of postoperative neurological status.

Summary Of Background Data: Spinal ependymomas have a variety of MRI findings preoperatively, including a hemorrhage cap sign, gadolinium enhancement, and a spinal tumor cyst. However, little is known about these features on postoperative MRI after tumor resection.

Materials And Methods: The subjects were 38 patients treated for spinal cord ependymoma of World Health Organization grade II at our hospital. All had a spinal tumor cyst on preoperative MRI. All cases were followed with MRI for >1 year after surgery, including imaging at postoperative months (POM) 1 and 12. The maximum diameter of the syrinx was measured on mid-sagittal MRI. The extent of tumor resection was categorized as gross total resection (GTR) and subtotal resection (STR).

Results: The mean age of the 38 patients (22 male and 16 female individuals) was 50.9 years (range, 21-71 y) at the time of surgery. The mean preoperative duration from disease onset was 14.9 months (range, 2-47 mo). GTR was achieved in 28 patients (74%) and STR in 10 (26%). The mean syrinx sizes preoperatively and at POM 1 and POM 12 were 7.5±2.3, 4.1±1.9, and 2.5±1.8 mm, respectively, with significant differences among the time points (P<0.01). The syrinx size shrunk over time after GTR and STR. The shrinkage rate was significantly higher in GTR cases (P<0.05) and in cases with the improvement of McCormick grade for neurological status after both GTR and STR (P<0.05).

Conclusions: These findings suggest that MRI can be used to evaluate the improvement of neurological status after surgery for spinal ependymoma.
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http://dx.doi.org/10.1097/BSD.0000000000001061DOI Listing
March 2021

Overcoming locomotive syndrome: The Yakumo Study.

Mod Rheumatol 2021 May 11;31(3):750-754. Epub 2021 Feb 11.

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.

Objectives: Improvement of life expectancy is increasingly important with the aging of society. The aim of the study was to compare physical performance in elderly people in two 3-year periods (2001-2003) and (2016-2018).

Methods: The participants were healthy Japanese elderly adults who attended public health check-ups in Yakumo. Results for 10 m gait time, two-step test, back muscle strength, and grip strength were examined prospectively for participants in 2001-2003 (Group A:  = 488) and 2016-2018 (Group B:  = 309) by gender and age (65-74 and 75-84 years).

Results: There were significant differences between Groups A and B for 10 m gait time (age 65-74: male: 5.6 vs. 5.2 s, female: 6.3 vs. 5.5 s; age 75-84: male: 6.1 vs. 5.5 s, female: 6.7 vs. 5.8 s; all  < .05) and two-step test (age 65-74: male: 1.41 vs. 1.48, female: 1.35 vs. 1.44; age 75-84: male: 1.32 vs. 1.41, female: 1.30 vs. 1.38; all  < .05), but not for back muscle strength or grip strength.

Conclusion: Our results suggest a phenomenon of 'overcoming locomotive syndrome', in which physical performance changed by aging, including motor functions such as 10 m gait time and two-step test, has improved in the current population compared with a similar population from 15 years ago.
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http://dx.doi.org/10.1080/14397595.2021.1879413DOI Listing
May 2021

Association Between Vitamin A Intake and Disease Severity in Early-Onset Heterotopic Ossification of the Posterior Longitudinal Ligament of the Spine.

Global Spine J 2021 Jan 25:2192568221989300. Epub 2021 Jan 25.

Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, Hokkaido, Japan.

Study Design: A sex- and age-matched case-control study and a cross-sectional study.

Objective: In our previous study, patients with early-onset (<50 years of age) ossification of the posterior longitudinal ligament (OPLL) had distinct features such as morbid obesity, a high prevalence of lifestyle-related diseases, and diffuse ossified lesions mainly affecting the thoracic spine. Our goals were to determine whether early-onset OPLL patients have unbalanced dietary habits and to identify nutritional factors associated with OPLL exacerbation.

Methods: In Study 1, the simple brief-type self-administered diet history questionnaire (BDHQ) was used to compare nutrient intake levels of early-onset OPLL patients (n = 13) with those of sex- and age-matched non-OPLL controls (n = 39) or with those of common OPLL (onset age ≥ 50 years, n = 62). In Study 2, serological validation was conducted for thoracic OPLL patients (n = 77) and non-OPLL controls (n = 101) in a nationwide multicenter study in Japan.

Results: The BDHQ showed that the early-onset OPLL patients had significantly lower intakes of vitamins A and B6 than non-OPLL controls. These results were validated by lower serum vitamins A and B6 levels in the early-onset thoracic OPLL patients. The severity of OPLL negatively correlated with serum vitamin A levels in male early-onset OPLL patients. The multiple regression analysis revealed that the severity of thoracic OPLL had an association with onset age and serum vitamin A level.

Conclusions: Vitamin A deficiency resulting from unbalanced dietary habits is associated with exacerbation of male early-onset OPLL.
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http://dx.doi.org/10.1177/2192568221989300DOI Listing
January 2021

Poor derivation of Tc-MEP baseline waveforms in surgery for ventral thoracic intradural extramedullary tumor: Efficacy of use of the abductor hallucis in cases with a preoperative non-ambulatory status.

J Clin Neurosci 2021 Feb 28;84:60-65. Epub 2020 Dec 28.

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan. Electronic address:

Most thoracic intradural extramedullary tumors (IDEMT) are benign lesions that are treated by gross total resection and spinal cord decompression. Intraoperative transcranial-motor evoked potential (Tc-MEP) monitoring is important for reducing postoperative neurological complications. The purpose of this study is to examine the characteristics of Tc-MEP waveforms in surgery for thoracic IDEMT resection based on location of the tumor relative to the spinal cord. The subjects were 56 patients who underwent surgery for thoracic IDEMT from 2010 to 2018. The waveform derivation rate for each lower muscle was examined at baseline and intraoperatively. 56 patients had a mean age of 61.7 years, and 21 (38%) were non-ambulatory before surgery. The tumors were schwannoma (n = 28, 50%), meningioma (n = 25, 45%), and neurofibroma (n = 3, 5%); and the lesions were dorsal (n = 29, 53%) and ventral (n = 27, 47%). There was a significantly higher rate of undetectable waveforms in all lower limb muscles in the ventral group compared to the dorsal group (15% vs. 3%, p < 0.05). In non-ambulatory cases, the derivation rate at baseline was significantly lower for ventral thoracic IDMETs (47% vs. 68%, p < 0.05). The abductor hallucis (AH) had the highest waveform derivation rate of all lower limb muscles in non-ambulatory cases with a ventral thoracic IDMET. Spinal cord compression by a ventral lesion may be increased, and this may be reflected in greater waveform deterioration. Of all lower limb muscles, the AH had the highest derivation rate, even in non-ambulatory cases with a ventral IDEMT, which suggests the efficacy of multichannel monitoring including the AH.
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http://dx.doi.org/10.1016/j.jocn.2020.11.045DOI Listing
February 2021

Primary cervical decompression surgery may improve lumbar symptoms in patients with tandem spinal stenosis.

Eur Spine J 2021 04 6;30(4):899-906. Epub 2021 Jan 6.

Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai, Showa-ku, Nagoya, Aichi, 466-8560, Japan.

Purpose: Tandem spinal stenosis (TSS) refers to coexisting lumbar and cervical canal stenosis. Evidence regarding whether cervical decompression improves lumbar symptoms in TSS is insufficient. Therefore, we determined the effectiveness of cervical decompression surgery for patients with lumbar spinal stenosis (LSS) and cervical spinal stenosis.

Methods: The records of 64 patients with TSS experiencing lumbar symptoms who underwent cervical decompression surgery between April 2013 and July 2017 at a single institution were retrospectively reviewed. We categorized patients into the Non-improved (n = 20), Relapsed (n = 30), and Maintained-improvement (n = 14) groups according to the presence or absence of improvement and relapse in lower limb symptoms in TSS following cervical decompression surgeries.

Results: Of 64 patients, 44 (69%) showed improved lower limb or low back symptoms, with 14 (22%) patients maintaining improvement. The preoperative cervical myelopathy-Japanese Orthopedic Association score and the preoperative number of steps determined using the 10-s step test were significantly lower in the Non-improved group than in the Maintained-improvement group. Receiver operating characteristic curve of preoperative 10-s step test results revealed 12 steps as a predictor for maintained improvement.

Conclusion: The improvement of LSS symptoms following cervical decompression surgeries may be associated with the severity of cervical myelopathy as determined in clinical findings rather than in imaging findings. Patients with TSS having a 10-s step test result of < 12 steps were more likely to experience a relapse of lower limb symptoms following cervical decompression surgeries.
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http://dx.doi.org/10.1007/s00586-020-06693-0DOI Listing
April 2021

Sacroiliac Joint Degeneration After Lumbopelvic Fixation.

Global Spine J 2020 Dec 30:2192568220978235. Epub 2020 Dec 30.

Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Shouwa-ku, Nagoya, Aichi, Japan.

Study Design: Retrospective Study.

Objectives: Sacroiliac buttress screws (SBS) and S2 alar iliac screws (SAI) are used as distal screws in cases with long fusion to the pelvis. Distal fixation ends, whether exceeding the sacroiliac joint (SIJ), may affect postoperative degenerative changes in the SIJ. The aim of this study was to investigate SIJ degeneration after lumbosacral and lumbopelvic fixation, using SBS and SAI in degenerative spine diseases, respectively.

Methods: This study included 70 patients aged ≥50 years with lumbosacral fusion (>3 levels). They were divided into 2 groups (SBS 20 and SAI 50 cases) based on the type of distal screws. Radiographical and clinical data were reviewed with a minimum 2-year follow-up. Radiographical SIJ degeneration was analyzed using computed tomography; clinical outcomes were evaluated using visual analog scale (VAS) and Japanese Orthopaedic Association Back Pain Questionnaire (JOABPEQ).

Results: No significant differences were observed in patients' preoperative characteristics between the 2 groups. The incidence of SIJ degeneration, including osteophyte formation (30.0% and 8.0%, p = 0.03), intraarticular air (75.0% and 16.0%, p < 0.001), and subchondral cyst (20.0% and 2.0%. p = 0.02) in SBS and SAI groups, respectively, at the follow-up, was significantly higher in the SBS group. Although SIJ degenerative changes were significantly different between the SBS and SAI groups, there was no significant difference in VAS and JOABPEQ scores between the groups at 2 years post-surgery.

Conclusions: Lumbosacral fusion can cause SIJ degeneration, which is more frequent when SBS are used in fixation to the sacrum.
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http://dx.doi.org/10.1177/2192568220978235DOI Listing
December 2020

Risk factors for delayed diagnosis of spinal fracture associated with diffuse idiopathic skeletal hyperostosis: A nationwide multiinstitution survey.

J Orthop Sci 2020 Dec 14. Epub 2020 Dec 14.

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Aichi, Japan; Japanese Organization for the Study for Ossification of Spinal Ligament (JOSL), 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan. Electronic address:

Background: Patients with DISH are susceptible to spinal fractures and subsequent neurological impairment, including after minor trauma. However, DISH is often asymptomatic and fractures may have minimal symptoms, which may lead to delayed diagnosis. The purpose of this study was to identify risk factors for delayed diagnosis of spinal fractures in patients with diffuse idiopathic skeletal hyperostosis (DISH).

Methods: The subjects were 285 patients with DISH surgically treated at 18 medical centers from 2005 to 2015. Cause of injury, imaging findings, neurological status at the times of injury and first hospital examination, and the time from injury to diagnosis were recorded. A delayed diagnosis was defined as that made >24 h after injury.

Results: Main causes of injury were minor trauma due to a fall from a standing or sitting position (51%) and high-energy trauma due to a fall from a high place (29%) or a traffic accident (12%). Delayed diagnosis occurred in 115 patients (40%; 35 females, 80 males; mean age 76.0 ± 10.4 years), while 170 (60%; 29 females, 141 males; mean age 74.6 ± 12.8 years) had early diagnosis. Delayed group had a significantly higher rate of minor trauma (n = 73, 63% vs. n = 73, 43%), significantly more Frankel grade E (intact neurological status) cases at the time of injury (n = 79, 69% vs. n = 73, 43%), and greater deterioration of Frankel grade from injury to diagnosis (34% vs. 8%, p < 0.01). In multivariate analysis, a minor trauma fall (OR 2.08; P < 0.05) and Frankel grade E at the time of injury (OR 2.29; P < 0.01) were significantly associated with delayed diagnosis.

Conclusion: In patients with DISH, it is important to keep in mind the possibility of spinal fracture, even in a situation in which patient sustained only minor trauma and shows no neurological deficit. This is because delayed diagnosis of spinal fracture can cause subsequent neurological deterioration.
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http://dx.doi.org/10.1016/j.jos.2020.10.019DOI Listing
December 2020

An intraoperative 3D image-based navigation error during cervical pedicle screw insertion.

Nagoya J Med Sci 2020 Nov;82(4):799-805

Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.

A 67-year-old man underwent posterior cervical decompression surgery for ossification of the posterior longitudinal ligament (OPLL) with fixation using cervical pedicle screws (CPSs) guided by intraoperative 3D image-based navigation. Intraoperatively, while creating the screw hole using the navigation probe, the virtual trajectory on the intraoperative navigation screen showed a 10-degree angle discrepancy in the axial plane depending on whether a probing force was or was not applied for making the hole. This was potentially caused by vertebra rotation and a bent probe. Consequently, the CPSs were placed more laterally than the ideal trajectory, which resulted in <2 mm lateral perforation to the foramen transversarium. There were no screw insertion-related perioperative complications. Based on this case, we conclude that navigation error during CPS insertion can occur even with intraoperative 3D image-based navigation. The risk of a bowed navigation probe caused by posterior cervical muscle and vertebra rotation should be considered, even with use of a navigation reference frame.
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http://dx.doi.org/10.18999/nagjms.82.4.799DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7719458PMC
November 2020

Surgical outcomes and factors related to postoperative motor and sensory deficits in resection for 244 cases of spinal schwannoma.

J Clin Neurosci 2020 Nov 25;81:6-11. Epub 2020 Sep 25.

Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, Aichi 466-8550, Japan. Electronic address:

In a large cohort the clinical presentation, management and outcomes of spinal schwannoma and factors related to postoperative motor and sensory deficits were invesgtigated. In 244 patients (males: 126, females: 118, average age 51.8 y) at one center, significant factors related to postoperative motor and sensory deficits were identified. Tumors were in the cervical (n = 79, 32.4%), lumbar (n = 66), thoracolumbar (T11-L1) (n = 55), and thoracic (n = 39) regions, and 5 patients had sacrum tumors. The rates of postoperative motor and sensory deterioration were 13.1% and 20.5%, respectively. The risk factors for motor deterioration were preoperative motor weakness, preoperative gait disturbance, dumbbell Eden type II, subtotal resection, and operative time, and those for postoperative sensory deficit were preoperative gait disturbance and subtotal resection. Of 12 patients with significant TcMEP changes, 11 had a new motor deficit after surgery; and of 216 patients with stable TcMEP data, 196 were neurologically intact after surgery (true negative) and 20 (11.0%) had deficits in the immediate postoperative stage (false negative). These deficits resolved during hospitalization for most patients. Of 15 patients with TcMEP deterioration and recovery, 11 (93.3%) had no motor deficits after surgery (p < 0.01).
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http://dx.doi.org/10.1016/j.jocn.2020.09.025DOI Listing
November 2020