Faculty Profiles - NAKASHIMA Hiroaki

Automated Detection of Spinal Schwannomas Utilizing Deep Learning Based on Object Detection From Magnetic Resonance Imaging

Ito, S; Ando, K; Kobayashi, K; Nakashima, H; Oda, M; Machino, M; Kanbara, S; Inoue, T; Yamaguchi, H; Koshimizu, H; Mori, K; Ishiguro, N; Imagama, S

SPINE Vol. 46 ( 2 ) page： 95 - 100 2021.1

Language：English Publisher：Spine

Study Design.A retrospective analysis of magnetic resonance imaging (MRI) was conducted.Objective.This study aims to develop an automated system for the detection of spinal schwannoma, by employing deep learning based on object detection from MRI. The performance of the proposed system was verified to compare the performances of spine surgeons.Summary of Background Data.Several MRI scans were conducted for the diagnoses of patients suspected to suffer from spinal diseases. Typically, spinal diseases do not involve tumors on the spinal cord, although a few tumors may exist at the unexpectable level or without symptom by chance. It is difficult to recognize these tumors; in some cases, these tumors may be overlooked. Hence, a deep learning approach based on object detection can minimize the probability of overlooking these tumors.Methods.Data from 50 patients with spinal schwannoma who had undergone MRI were retrospectively reviewed. Sagittal T1- and T2-weighted magnetic resonance imaging (T1WI and T2WI) were used in the object detection training and for validation. You Only Look Once version3 was used to develop the object detection system, and its accuracy was calculated. The performance of the proposed system was compared to that of two doctors.Results.The accuracies of the proposed object detection based on T1W1, T2W1, and both T1W1 and T2W1 were 80.3%, 91.0%, and 93.5%, respectively. The accuracies of the doctors were 90.2% and 89.3%.Conclusion.Automated object detection of spinal schwannoma was achieved. The proposed system yielded a high accuracy that was comparable to that of the doctors.Level of Evidence: 4.

DOI： 10.1097/BRS.0000000000003749

Zonisamide ameliorates neuropathic pain partly by suppressing microglial activation in the spinal cord in a mouse model Reviewed

Transdiaphragmatic Approach as a Novel Less Invasive Retroperitoneal Approach at Thoracolumbar Junction: Comparison with Conventional Diaphragmatic Incision Reviewed Open Access

Nakashima Hiroaki, Kanemura Tokumi, Satake Kotaro, Ito Kenyu, Tanaka Satoshi, Segi Naoki, Ouchida Jun, Ando Kei, Kobayashi Kazuyoshi, Imagama Shiro

Spine Surgery and Related Research Vol. 5 ( 6 ) page： 405 - 411 2021

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

Introduction: Lateral corpectomy has been considered a minimally invasive surgery, allowing a "transdiaphragmatic approach" at the thoracolumbar junction. This approach allows for a small diaphragmatic incision directly in the retroperitoneal space and the affected vertebra. However, its effectiveness in comparison to a conventional approach remains unclear. Thus, in this present study, we compared the surgical outcomes between conventional diaphragmatic detachment and the transdiaphragmatic approach in patients with vertebral fracture at the thoracolumbar junction.Methods: In total, 31 patients with a vertebral fracture at the thoracolumbar junction (T12-L2) were included in this study: 17 underwent a conventional approach, whereas 14 underwent a transdiaphragmatic approach, with a minimum 2-year follow-up. The effectiveness of surgery was evaluated in each category of the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ).Results: Operative time and estimated blood loss were determined to be significantly shorter in the transdiaphragmatic than in the conventional approach. Perioperative complications were observed in the conventional approach (one atelectasis and one pleural effusion), while no complication was noted in the transdiaphragmatic approach. There were no significant differences in postoperative quality of life as assessed by JOABPEQ in terms of pain-related disorders, lumbar spine dysfunction, gait disturbance, social life dysfunction, or psychological disorders between the conventional and transdiaphragmatic approaches.Conclusions: A "transdiaphragmatic approach" using lateral access surgery has been found to be associated with a shorter operative time and less blood loss with fewer complications than the conventional approach. Given that equivalent clinical outcomes were achieved in both conventional and transdiaphragmatic approaches, this "transdiaphragmatic approach" could be useful because of its minimal invasiveness.

DOI： 10.22603/ssrr.2020-0191

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

Ito Kenyu, Ando Kei, Kobayashi Kazuyoshi, Nakashima Hiroaki, Hasegawa Yukihiro, Imagama Shiro

Spine Surgery and Related Research Vol. 5 ( 3 ) page： 160 - 164 2021

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

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.

DOI： 10.22603/ssrr.2020-0123

Koshimizu, H; Ohkawara, B; Nakashima, H; Ota, K; Kanbara, S; Inoue, T; Tomita, H; Sayo, A; Kiryu-Seo, S; Konishi, H; Ito, M; Masuda, A; Ishiguro, N; Imagama, S; Kiyama, H; Ohno, K

LIFE SCIENCES Vol. 263 page： 118577 2020.12

Language：English Publisher：Life Sciences

Neuropathic pain is caused by a lesion or a functional impairment of the sensory nervous system and allodynia is one of the frequently observed symptoms in neuropathic pain. Allodynia represents abnormal pain due to a non-noxious stimulus that does not normally provoke pain. Cellular mechanisms underlying neuropathic pain remain mostly elusive, and partial pain relief can be achieved in a limited number of patients by antidepressants, anticonvulsants topical anesthetics, and others. Zonisamide (ZNS) is widely used as an anti-epileptic and anti-Parkinson's disease drug. A recent report shows that ZNS suppresses neuropathic pain associated with diabetes mellitus in a mouse model. We made a mouse model of neuropathic pain in the hindlimb by cutting the nerve at the intervertebral canal at lumbar level 4 (L4). At 28 days after nerve injury, ZNS ameliorated allodynic pain, and reduced the expression of inflammatory cytokines and the nerve injury-induced increase of Iba1-positive microglia in the spinal dorsal horn at L4. In BV2 microglial cells, ZNS reduced the number of lipopolysaccharide-induced amoeboid-shaped cells, representing activated microglia. These results suggest that ZNS is a potential therapeutic agent for neuropathic pain partly by suppressing microglia-mediated neuroinflammation.

DOI： 10.1016/j.lfs.2020.118577

Scoliosis Caused by Limb-Length Discrepancy in Children.

Kobayashi K, Ando K, Nakashima H, Machino M, Morozumi M, Kanbara S, Ito S, Inoue T, Yamaguchi H, Mishima K, Ishiguro N, Imagama S

Asian spine journal Vol. 14 ( 6 ) page： 801 - 807 2020.12

An intraoperative 3D image-based navigation error during cervical pedicle screw insertion Reviewed Open Access

Nakashima, H; Ishikawa, Y; Ando, K; Kobayashi, K; Ishiguro, N; Imagama, S

NAGOYA JOURNAL OF MEDICAL SCIENCE Vol. 82 ( 4 ) page： 799 - 805 2020.11

Language：English Publisher：Nagoya Journal of Medical Science

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.

DOI： 10.18999/nagjms.82.4.799

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

Ando, K; Kobayashi, K; Nakashima, H; Machino, M; Ito, S; Kanbara, S; Inoue, T; Segi, N; Koshimizu, H; Imagama, S

JOURNAL OF CLINICAL NEUROSCIENCE Vol. 81 page： 6 - 11 2020.11

Language：English Publisher：Journal of Clinical Neuroscience

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).

DOI： 10.1016/j.jocn.2020.09.025

Prediction of outcome following laminoplasty of cervical spondylotic myelopathy: Focus on the minimum clinically important difference

Machino, M; Ando, K; Kobayashi, K; Nakashima, H; Kanbara, S; Ito, S; Inoue, T; Koshimizu, H; Ito, K; Kato, F; Imagama, S

JOURNAL OF CLINICAL NEUROSCIENCE Vol. 81 page： 321 - 327 2020.11

Language：English Publisher：Journal of Clinical Neuroscience

The minimum clinically important difference (MCID) of the Japanese Orthopaedic Association (JOA) score has been reported to be around 2.5 points in cervical myelopathy. This study sought to define significant predictive factors on achieving the MCID following laminoplasty in a large series of patients with cervical spondylotic myelopathy (CSM). A total of 485 consecutive patients with CSM (295 males and 190 females; mean age: 67.0 years; age range: 42–91 years) who underwent laminoplasty were prospectively enrolled. The average postoperative follow-up period was 26.6 months (range: 12–66 months). We calculated the achieved JOA score. The relationships between outcomes and various clinical and imaging predictors including comorbidity and quantitative performance tests were examined. Logistic regression analysis was conducted to identify the predictors correlated with a JOA score of 2.5 points or more. Clinically meaningful gains were exhibited in 299 patients (61.6%) with a JOA score of ≥2.5 points, whereas 186 patients (38.4%) achieved a JOA score of <2.5 points. Univariate logistic regression analysis showed the predictive factors with a shorter duration of CSM symptoms, lower preoperative JOA scores, absence of hypertension, no use of anticoagulant/antiplatelet agents, and nonsmoking status. Multivariate logistic regression analysis determined that the duration of CSM symptoms (odds ratio: 0.771, 95% confidence interval: 0.705–0.844; p < 0.01) was the only significant predictive factor for achieving JOA scores of ≥2.5 points. An important predictor of MCID achievement following laminoplasty was shorter duration of CSM symptoms.

DOI： 10.1016/j.jocn.2020.09.065

Larger muscle mass of the upper limb correlates with lower amplitudes of deltoid MEPs following transcranial stimulation

Ito, S; Ando, K; Kobayashi, K; Nakashima, H; Machino, M; Kanbara, S; Inoue, T; Yamaguchi, H; Segi, N; Koshimizu, H; Imagama, S

JOURNAL OF CLINICAL NEUROSCIENCE Vol. 81 page： 426 - 430 2020.11

Language：English Publisher：Journal of Clinical Neuroscience

To perform spinal surgery safely, it is important to understand the risk factors, including factors that negatively influence intraoperative neuromonitoring (IONM). Transcranial motor evoked potentials (TcMEPs) are important in IONM. Therefore, we aimed to investigate whether muscle mass affects the waveforms of TcMEPs to understand the risk factors influencing TcMEPs. We enrolled 48 patients with thoracolumbar spinal diseases who underwent surgery at our facility between April 2015 and March 2018. Before surgery, the body composition, including muscle mass and fat mass, of all patients was measured using bioelectrical impedance analysis (BIA). During surgery, cranial stimulation under general anesthesia was used to derive TcMEPs, enabling us to measure the amplitude, using the control wave of the TcMEPs of the deltoid muscles and the abductor digiti minimi (ADM) muscles. We found a negative correlation between the amplitude of deltoid-muscle TcMEPs and muscle mass of the upper limb. The amplitude of deltoid-muscle TcMEPs did not correlate with the skeletal muscle index (SMI), muscle mass of the lower limb, or body fat mass. The amplitude of ADM-muscle TcMEPs did not correlate with SMI, muscle mass of any limb, or body fat mass. In conclusion, a larger muscle mass of the upper limb correlated with a lower amplitude of deltoid-muscle TcMEPs. By contrast, there was no correlation between the muscle mass of the upper limb and the amplitude of ADM-muscle TcMEPs. These findings suggest that TcMEPs of the ADM are less influenced by muscle mass and are more stable than those of the deltoid.

DOI： 10.1016/j.jocn.2020.10.004

Dynamic changes in longitudinal stretching of the spinal cord in thoracic spine: Focus on the spinal cord occupation rate of dural sac

Machino, M; Morita, D; Ando, K; Kobayashi, K; Nakashima, H; Kanbara, S; Ito, S; Inoue, T; Koshimizu, H; Ito, K; Kato, F; Imagama, S

CLINICAL NEUROLOGY AND NEUROSURGERY Vol. 198 page： 106225 2020.11

Language：English Publisher：Clinical Neurology and Neurosurgery

Objectives: This study aimed to evaluate the anteroposterior diameters and cross-sectional areas of the dural sac and spinal cord in the thoracic spine, to elucidate the spinal cord occupation rate of the dural sac in these dynamic changes for each level using multidetector-row computed tomography (MDCT). Patients and Methods: Fifty patients with cervical or lumbar spinal disease were prospectively enrolled. After preoperative myelography, MDCT was performed at maximum passive ﬂexion and extension. The anteroposterior diameter and cross-sectional area of the dural sac and spinal cord in the axial plane and the thoracic spinal cord length in the sagittal plane were measured. The spinal cord occupation rate in the dural sac was calculated. Results: The spinal cord occupation rate of the dural sac in anteroposterior diameter was lower on ﬂexion than on extension, with signiﬁcant differences from the T1/T2 to T11/T12 levels (p < 0.0001). The spinal cord occupation rate of the dural sac in cross-sectional area was lower on ﬂexion than on extension, with signiﬁcant differences except from T3/T4 to T6/T7 levels (p < 0.01). There was a bimodal increase in the occupation rate with elevations at the cervicothoracic junction and thoracolumbar junction. The thoracic spinal cord length on ﬂexion was signiﬁcantly longer than that on extension (p < 0.0001). Conclusions: The spinal cord occupation rate of the dural sac was lower on ﬂexion than on extension, despite thoracic spine being considered a rigid region. The dynamic changes in longitudinal stretching and shrinkage of the spinal cord affected the occupation rate.

DOI： 10.1016/j.clineuro.2020.106225

Trends in Reoperation for Surgical Site Infection after Spinal Surgery with Instrumentation in a Multicenter Study. Reviewed

Kobayashi K, Imagama S, Ando K, Nakashima H, Kato F, Sato K, Kanemura T, Matsubara Y, Yoshihara H, Hirasawa A, Deguchi M, Shinjo R, Sakai Y, Inoue H, Ishiguro N

Spine Vol. 45 ( 20 ) page： 1459 - 1466 2020.10

Preoperative 6-Minute Walk Performance in Children With Congenital Scoliosis

Nakashima, H; Kawakami, N; Matsumoto, H; Redding, GJ

JOURNAL OF PEDIATRIC ORTHOPAEDICS Vol. 40 ( 9 ) page： E818 - E821 2020.10

Language：English Publisher：Journal of Pediatric Orthopaedics

Background:The 6-minute walk test (6MWT) is used to assess the function of cardiopulmonary and neuromuscular conditions in adults and children. The primary research question was to determine the relationship between 6MWT distance and forced vital capacity (FVC) and the major curve among children with congenital scoliosis with rib anomalies.Methods:The authors recorded 6MWT distance in meters, FVC as a percentage of predicted normal value using arm span for height (FVC%), and Cobb angle in 20 children (13 girls; average age, 6.7±1.3 y) with congenital scoliosis before outpatient surgical treatment. The 6MWT uses a standardized protocol and measures distance traveled in 6 minutes on a flat surface. The authors then determined the correlation between these measures using linear regression analysis.Results:The Cobb angle of the major curvature was 55.4±20.5 degrees. The type of vertebral anomaly was mixed in 17 cases, formation failure in 2 cases, and segmentation failure in 1 case. The range of rib anomalies was 3.4±3.9 levels; 15 and 5 patients, respectively, had unilateral and bilateral rib anomalies. FVC and FVC% were 0.7±0.2 L and 60%±19%, respectively. The ratio of forced expiratory volume at 1 second to FVC (FEV<inf>1</inf>/FVC), which indicates obstructive lung disease, was normal at 93%±7%. The 6MWT distance was 386.3±59.4 m, which was ≤10% of the predicted distance for normal children. No child was able to walk the normal distance on the basis of published norms. 6MWT distance was significantly correlated with arm span (ρ=0.46, P=0.04) and major curve (ρ=-0.61, P=0.004), but not with FVC% (ρ=0.17, P=0.49).Conclusions:The 6MWT distance is a feasible measure of function and is substantially reduced before surgery in children with thoracic congenital scoliosis with rib anomalies. The 6MWT distance was significantly correlated with a major curve but not with FVC%. 6MWT distance is not affected by moderate lung function impairment.Level of Evidence:Level IV - retrospective cohort study.

DOI： 10.1097/BPO.0000000000001641

Patient-Reported Quality of Life Following Posterior Lumbar Interbody Fusion or Indirect Decompression Using Lateral Lumbar Interbody Fusion.

特集脊椎硬膜病変-最近の話題脊髄ヘルニアの病態と治療

中島宏彰, 今釜史郎, 安藤圭, 小林和克, 八木秀樹

脊椎脊髄ジャーナル Vol. 33 ( 9 ) page： 865 - 869 2020.9

Influence of Global Spine Sagittal Balance and Spinal Degenerative Changes on Locomotive Syndrome Risk in a Middle-Age and Elderly Community-Living Population Reviewed Open Access

Machino, M; Ando, K; Kobayashi, K; Nakashima, H; Kanbara, S; Ito, S; Inoue, T; Yamaguchi, H; Koshimizu, H; Seki, T; Ishizuka, S; Takegami, Y; Ishiguro, N; Hasegawa, Y; Imagama, S

BIOMED RESEARCH INTERNATIONAL Vol. 2020 page： 3274864 2020.9

Language：English Publisher：Biomed Research International

Purpose. The aim of this study was to describe the characteristics of each locomotive syndrome (LS) risk stage, including global spine sagittal alignment, spinal degenerative changes evident on plain radiographs, low back pain (LBP), muscle strength, and physical ability in middle-aged and elderly people in a health checkup. Methods. This study included 211 healthy Japanese volunteers (89 men and 122 women; mean age, 64.0 years) who underwent assessment with both radiographs and Spinal Mouse. Spinal sagittal parameters included thoracic kyphosis angle (TKA), lumbar lordosis angle (LLA), sagittal vertical axis, and spinal inclination angle (SIA). Lumbar disc height (LDH) and lumbar osteophyte formation (LOF) at each level were evaluated as the spinal degenerative changes. The LS assessment comprised three tests: Stand-up test, two-step test, and 25-question Geriatric Locomotive Function Scale (GLFS-25). The subjects were divided into three groups (no risk, stage 1 LS, or stage 2 LS) according to LS risk test criteria. The prevalence of LBP was investigated with a visual analogue scale (VAS), and physical performances were also compared among the groups. Results. Of the participants, 122 had no risk of LS, 56 had stage 1 LS risk, and 29 had stage 2 LS risk. With increasing LS risk stage, the prevalence of and VAS score for LBP increased significantly, and back muscle strength and physical abilities decreased significantly. The TKA did not differ among the three groups. The LLA decreased gradually with LS risk stage (P=0.0001). At each level except L1-L2 and L5-S1, LDH decreased gradually with LS risk stage. The prevalence of LOF increased significantly with increasing LS risk stage. The SIA increased significantly with LS risk stage (P=0.0167). Conclusions. Participants with LS had higher prevalence of spinal degeneration, small LLA, and global spinal imbalance by anterior spinal inclination.

DOI： 10.1155/2020/3274864

Nakashima H, Kanemura T, Satake K, Ito K, Tanaka S, Ouchida J, Segi N, Kobayashi K, Ando K, Ishiguro N, Imagama S

Spine Vol. 45 ( 18 ) page： E1172 - E1178 2020.9

Differences of locomotive syndrome and frailty in community-dwelling middle-aged and elderly people: Pain, osteoarthritis, spinal alignment, body balance, and quality of life. Reviewed

Imagama S, Ando K, Kobayashi K, Machino M, Tanaka S, Morozumi M, Kanbara S, Ito S, Seki T, Ishizuka S, Nakashima H, Ishiguro N, Hasegawa Y

Modern rheumatology Vol. 30 ( 5 ) page： 921 - 929 2020.9

Impact of pelvic incidence on lumbar osteophyte formation and disc degeneration in middle-aged and elderly people in a prospective cross-sectional cohort Reviewed

Imagama Shiro, Ando Kei, Kobayashi Kazuyoshi, Machino Masaaki, Tanaka Satoshi, Morozumi Masayoshi, Kanbara Shunsuke, Ito Sadayuki, Inoue Taro, Seki Taisuke, Ishizuka Shinya, Nakashima Hiroaki, Ishiguro Naoki, Hasegawa Yukiharu

EUROPEAN SPINE JOURNAL Vol. 29 ( 9 ) page： 2262 - 2271 2020.9

Inoue, T; Ito, K; Ando, K; Kobayashi, K; Nakashima, H; Katayama, Y; Machino, M; Kanbara, S; Ito, S; Yamaguchi, H; Koshimizu, H; Kato, F; Imagama, S

EUROPEAN SPINE JOURNAL Vol. 29 ( 9 ) page： 2378 - 2383 2020.9

Language：English Publisher：European Spine Journal

Purpose: To identify age-related changes and the relationship between upper and lower cervical sagittal alignment and the range of motion (ROM). Methods: A total of 600 asymptomatic volunteers were enrolled. There were 50 males and 50 females in each decade of life between the third and the eighth. The O–C2 angle and the C2–7 angle were measured using the neutral radiographs of the cervical spine. ROM was assessed by measuring the difference in alignment in the neutral, flexion, and extension positions. Results: The mean O–C2 angle in the neutral position was 14.0° lordotic. The mean ROM of the O–C2 angle was 23.1°. The mean C2–7 angle in the neutral position was 14.3° lordotic. The mean ROM of the C2–7 angle was 56.0°. The O–C2 angle was 16.1° in the third decade and gradually decreased to 11.4° in the eighth decade. There were no significant age-related changes in the ROM of the O–C2 angle. The C2–7 angle was 7.2° in the third decade and gradually increased to 20.8° in the eighth decade, and the ROM gradually decreased with increasing age. Significant negative correlation was observed between O–C2 angle and C2–7 angle. Conclusion: The O–C2 angle gradually decreased and the C2–7 angle increased with age. The ROM of the O–C2 angle did not change, but the ROM of the C2–7 angle decreased with age. The upper and lower cervical spine showed different age-related changes.

DOI： 10.1007/s00586-020-06547-9

True accuracy of percutaneous pedicle screw placement in thoracic and lumbar spinal fixation with a CT-based navigation system: Intraoperative and postoperative assessment of 763 percutaneous pedicle screws Reviewed

Ouchida, J; Kanemura, T; Satake, K; Nakashima, H; Segi, N; Suzuki, K; Imagama, S

JOURNAL OF CLINICAL NEUROSCIENCE Vol. 79 page： 1 - 6 2020.9

Language：English Publisher：Journal of Clinical Neuroscience

Purpose: To investigate intraoperative reinsertion of percutaneous pedicle screw (PPS) with intraoperative CT-based navigation and to evaluate the rate of deviation of PPS at postoperative radiographic examination. Methods: Seven hundred sixty-three screws were inserted in 138 patients. We investigated the rate of occurrence of intraoperative PPS reinsertion after the diagnosis of screw deviation by fluoroscopy and the causes of each screw deviation. The subsequent distribution of PPS deviation was evaluated by postoperative CT. We also assess the difference in variance between the group judged to be PPS misplaced intra-/postoperatively (IOD group/POD group) and appropriate PPS placement (ND group). Results: Among all the screws inserted, 10 (1.3%) were diagnosed as being deviated by fluoroscopy during surgery, and 74 (9.7%) screws were found to be deviated at postoperative CT evaluation. We found more pedicle screw mismatch in the POD group than in the ND group (52.7 vs 11.0%, P < 0.001). The distance between the screw and the reference was greater in the IOD group than that in the ND group (1.4 ± 1.2 vs 2.4 ± 1.1 vertebral levels, P = 0.016). In one patient in the IOD group, a motor function deficit was observed postoperatively. Conclusion: PPS fixation under intraoperative CT-based navigation did not prevent screw deviation completely. It is necessary to consider errors that occur during surgery and to confirm placement with real-time assistance such as fluoroscopy even in a surgery performed under CT navigation assistance.

DOI： 10.1016/j.jocn.2020.07.012