Progressive Relapse of Ligamentum Flavum Ossification Following Decompressive Surgery

Kei Ando,Shiro Imagama,Zenya Ito,Kazuyoshi Kobayashi,Junichi Ukai,Akio Muramoto,Ryuichi Shinjo,Tomohiro Matsumoto,Hiroaki Nakashima,Naoki Ishiguro 대한척추외과학회 2014 Asian Spine Journal Vol.8 No.6

Thoracic ossification of the ligamentum flavum (T-OLF) is a relatively rare spinal disorder that generally requires surgical intervention, due to its progressive nature and the poor response to conservative therapy. The prevalence of OLF has been reported at 3.8%–26%, which is similar to that of cervical ossification of the posterior longitudinal ligament (OPLL). The progression of OPLL after cervical laminoplasty for the treatment of OPLL is often shown in long-term follow-up. However, there have been no reports on the progression of OLF following surgery. We report a case of thoracic myelopathy secondary to the progressive relapse of OLF following laminectomy.

Single-Stage Removal of Thoracic Dumbbell Tumors from a Posterior Approach Only with Costotransversectomy

Kei Ando,Shiro Imagama,Norimitsu Wakao,Kenichi Hirano,Ryoji Tauchi,Akio Muramoto,Hiroki Matsui,Tomohiro Matsumoto,Yukihiro Matsuyama,Naoki Ishiguro 연세대학교의과대학 2012 Yonsei medical journal Vol.53 No.3

Purpose: Thoracic dumbbell tumors are relatively rare, usually arising from neurogenic elements. Methods for surgical removal thereof remain controversial. The purpose of this study was to evaluate the surgical results of a single-stage posterior approach with laminectomy and costotransversectomy only for the management of thoracic dumbbell tumors. Materials and Methods: Eight cases of thoracic large dumbbell tumor were analyzed retrospectively: seven men and one woman (mean age, 49 years). Pathologic findings included schwannoma in five patients, neurofibroma in two patients (Recklinghausen in one patient), and ganglioneuroma in one patient. All patients underwent single-stage removal of dumbbell tumors by a posterior approach followed by laminectomy and costotransversectomy combined with instrumentation. Clinical and radiologic outcomes were reviewed, thereafter. Results: Operative time ranged from 185 to 420 minutes (mean, 313 minutes), with estimated blood loss ranging from 71 to 1830 mL (mean, 658 mL). Postoperative complications included atelectasis in one case. All patients had tumors successfully removed with no neurological deterioration. Spinal deformities were not observed in any patients at the last follow-up (mean, 52 months), with instrumentation. Conclusion: Single-stage surgery with laminectomy and costotransversectomy may be useful for removing thoracic dumbbell tumors without a combined anterior approach.

Scoliosis Caused by Limb-Length Discrepancy in Children

Kobayashi Kazuyoshi,Ando Kei,Nakashima Hiroaki,Machino Masaaki,Morozumi Masayoshi,Kanbara Shunsuke,Ito Sadayuki,Inoue Taro,Yamaguchi Hidetoshi,Mishima Kenichi,Ishiguro Naoki,Imagama Shiro 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.6

Study Design: Single-center retrospective study in pediatric patients.Purpose: The purpose of the study was to investigate the effects of the presence and severity of leg-length discrepancy (LLD) on scoliosis in children.Overview of Literature: LLD is a common orthopedic problem that can result in standing imbalance, low back pain, and stress fractures. It may cause structural changes in the spine over time, but the exact effect of LLD on scoliosis is unknown.Methods: The subjects were 23 children with LLD ≥20 mm (range, 27–65 mm) treated at Nagoya University Hospital between 2007 and 2017. Whole spine posteroanterior standing radiographs and whole lower limb radiographs in a supine position were recorded. Data were collected for demographics, LLD, Cobb angle, pelvic obliquity, and Nash/Moe index. Scoliosis was defined as a Cobb angle ≥10°. Leg length was measured from the top of the femoral head to the middle of the tibial plafond, and LLD was defined as the difference between the left and right leg lengths.Results: The patients (nine males and 14 females) had a mean age of 14.0 years (range, 5–18 years). The average LLD was 44.3±17.2 mm, with LLDs of 20 to 39 mm, 40 to 59 mm, and ≥60 mm in 13, five, and five subjects, respectively. The average Cobb angle was 13.0°±7.0°, and 15 subjects (65%) had scoliosis. Convexity of the scoliosis was to the short leg side in all cases. The Cobb angle was significantly related to the severity of the LLD (<i>R</i>=0.736, <i>p</i><0.01), pelvic obliquity (<i>R</i>=0.966, <i>p</i><0.01), and Nash/Moe index (<i>p</i><0.05).Conclusions: LLD is a common pediatric condition that can cause scoliosis of the spine. Severe scoliosis may develop if the LLD is ≥30 mm. Long-term studies are needed to examine the effect of LLD resolution on the elimination of scoliosis.

Efficacy of Anal Needle Electrodes for Intraoperative Spinal Cord Monitoring with Transcranial Muscle Action Potentials

Kazuyoshi Kobayashi,Kei Ando,Hideki Yagi,Kenyu Ito,Mikito Tsushima,Masayoshi Morozumi,Satoshi Tanaka,Masaaki Machino,Kyotaro Ota,Yukihiro Matsuyama,Naoki Ishiguro,Shiro Imagama 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.4

Study Design: Retrospective study. Purpose: To examine the relationship between postoperative bowel bladder disorder (BBD) and the efficacy of needle electrodes for the external anal sphincter (EAS) in intraoperative spinal cord monitoring with transcranial muscle action potentials (Tc-MsEP). Overview of Literature: Spinal surgery for spina bifida, spinal cord tumor, and spinal tethered cord syndrome has a high rate of postoperative BBD. Monitoring of the EAS with Tc-MsEP is frequently performed during spinal surgery. We initially used plug-surface electrodes for this purpose, but have more recently switched to needle electrodes for the monitoring of the EAS. To date, there has been no comparison between the utility of these electrodes. Methods: Waveform derivation, exacerbation of postoperative BBD, and sensitivity and specificity for prediction of BBD by 70% amplitude reduction of EAS activity using needle and plug-surface electrodes were investigated in 239 spine surgeries. The cut-off for the % drop in amplitude for BBD prediction was determined for EAS monitoring using a needle electrode. Results: The overall rate of postoperative BBD aggravation was 7.1% (17/239 cases), with the individual rates using needle and plug-surface electrodes being 6.9% (8/116) and 7.3% (9/123), respectively. The waveform derivation rate was significantly higher using needle electrodes (91.3% [106/116] vs. 76.4% [94/123], p <0.01). In patients with baseline waveform detection, the sensitivity and specificity for postoperative BBD were similar in the two groups. With needle electrodes, a cutoff amplitude of Tc-MsEP for the EAS at the end of surgery of 25% of the baseline amplitude had a sensitivity of 89% and specificity of 82% for the prediction of postoperative BBD aggravation. Conclusions: The significantly higher waveform derivation rate using needle electrodes suggests that these electrodes are effective for monitoring the EAS in spinal surgery in cases with preoperative BBD.

Neutrino burst and gravitational wave from supernova explosions

Katsuhiko Sato,Kei Kotake,Keitaro Takahashi,Shin'ichiro Ando 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.1

The time prole and energy spectrum of a neutrino burst from supernovae is greatly modied by the eect of neutrino oscillations. We review how these conversions happen in a supernova mantle and how the burst could be detected by SK (Super-Kamiokande) and SNO (Sudbury Neutrino Observatory). We show that implications for neutrino parameters (mass hierarchy and the mixing angle between mass eigenstate 1; 3), can be obtained if a supernova appears at the Galactic Center. We also discuss the eects of neutrino oscillation on the supernova relic neutrino observations. In the end, we discuss the gravitational radiation from the rotating stellar cores, which will give us the information of the angular momentum distribution for evolved massive stars.

Persistence of Denosumab Therapy among Patients with Osteoporosis

Kobayashi Kazuyoshi,Ando Kei,Machino Masaaki,Morozumi Masayoshi,Kanbara Shunsuke,Ito Sadayuki,Inoue Taro,Yamaguchi Hidetoshi,Ishiguro Naoki,Imagama Shiro 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.4

Study Design: Retrospective study in a single center.Purpose: To examine denosumab persistence in patients of different ages with severe osteoporosis in Japan.Overview of Literature: Denosumab is an antibody drug used for the treatment of osteoporosis. It is mainly used in patients with severe osteoporosis who might have high motivation for treatment, and the need for only semi-annual subcutaneous injection might improve the continuation rate. However, no English-language articles have reported on denosumab persistence in the Japanese population, including young people, despite the importance of this issue in a super-aging society. Methods: The subjects started treatment with subcutaneous denosumab in our department from July 2013 until December 2017. Persistence rates were calculated using Kaplan-Meier curves. Patients were defined as “persistent” or “non-persistent” according to the use of therapy after 60 months.Results: The study included 101 patients (84 females) with a median follow-up period of 23.6±14.2 months. The persistence rate declined to 85.3%, 78.3%, 74.1%, 71.3%, and 69.3% at 12, 24, 36, 48, and 60 months, respectively. Age at the initiation of denosumab therapy differed significantly between non-persistent (n=31) and persistent (n=70) patients (81.3 vs. 72.8 years, <i>p</i> <0.01). Persistence was significantly lower in patients aged ≥80 years than in those aged <60 and 60–79 years (both <i>p</i> <0.01). The reasons for non-persistence of denosumab therapy were transfer to another hospital (n=13), interruption of outpatient visits (n=11), dental treatment (n=4), adverse events (n=2), and patient request (n=1).Conclusions: Persistence was significantly lower in patients aged ≥80 years than in patients of other ages, and strategies promoting persistence are needed for these elderly patients.

Perioperative Management of Patients with Hemophilia during Spinal Surgery

Kazuyoshi Kobayashi,Shiro Imagama,Kei Ando,Kenyu Ito,Mikito Tsushima,Masayoshi Morozumi,Satoshi Tanaka,Masaaki Machino,Kyotaro Ota,Yoshihiro Nishida,Naoki Ishiguro 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.3

Study Design: Single-center retrospective study. Purpose: To optimize the perioperative management of patients with hemophilia who are undergoing spinal surgery. Overview of Literature: Hemophilia is a rare disease in which there is a tendency of bleeding because of a congenital deficiency in blood coagulation factor activity. There has been no previous report on spinal surgery in patients with hemophilia. Methods: The subjects were five patients (all males) with hemophilia who underwent spinal surgery at Nagoya University Hospital. Two patients had hemophilia A (deficiency of factor VIII) and three had hemophilia B (deficiency of factor IX). The mean age at the time of surgery was 63 years (range, 46–73 years). The following surgeries were performed: posterior lumbar interbody fusion (PLIF) in two patients, and lumbar fenestration, cervical laminoplasty and lumbar fenestration, and cervical laminoplasty and PLIF in one patient each. Results: Coagulation factor at a mean dose of 4.8 ×103 U (range, 3–6 ×103 U) was intravenously injected before surgery, and a mean dose of 5.2 ×103 U (rang, 4–6 ×103 U) was continuously administered for 24 hours after surgery. Factor activity was maintained at ≥80% until postoperative day 14 and at ≥50% thereafter. The average duration of surgery was 178 minutes (range, 133–233 minutes), the estimated blood loss was 661 mL (range, 272–1,344 mL), and a drain tube was left subfascially in place for 2 days in all patients. Reoperation due to postoperative surgical site infection was required in one patient, but there were no complications due to hemorrhagic diathesis. The total dose of coagulation factor administered during hospitalization was 102 ×103 U (range, 46–198 ×103 U). Conclusions: Coordination with a hematologist and dose adjustment of the coagulation factor preparation to maintain a target level of coagulation factor activity facilitated a smooth postoperative course with perioperative control of bleeding during spinal surgery for patients with hemophilia.

Association between Postoperative Neck Pain and Intraoperative Transcranial Motor-Evoked Potential Waveforms of the Trapezius Muscles in Patients with Cervical Myelopathy Who Underwent Cervical Laminoplasty

Ito Sadayuki,Sakai Yoshihito,Ando Kei,Nakashima Hiroaki,Machino Masaaki,Segi Naoki,Tomita Hiroyuki,Koshimizu Hiroyuki,Hida Tetsuro,Ito Kenyu,Harada Atsushi,Imagama Shiro 대한척추외과학회 2023 Asian Spine Journal Vol.17 No.2

Study Design: Retrospective study.Purpose: Cervical laminoplasty is safe and effective for treating cervical myelopathy but has a higher frequency of postoperative axial pain compared to other methods. Several studies have reported on the causes of postoperative axial pain, but none have fully elucidated them. This study aimed to investigate the association between postoperative neck pain and intraoperative transcranial motor-evoked potential (MEP) waveforms of the trapezius muscles using transcranial MEPs.Overview of Literature: Few studies have investigated the association between postoperative neck pain and intraoperative transcranial MEP waveforms of the trapezius muscles in patients with cervical laminoplasty.Methods: A total of 79 patients with cervical myelopathy who underwent cervical laminoplasty at our facility between June 2010 and March 2013 were included in this study. Intraoperative control and final waveform were evaluated based on the trapezius muscle MEPs by measuring the latency and amplitude. A neck pain group comprised patients with higher neck pain Visual Analog Scale scores from preoperative value to 1 year postoperatively. The cross-sectional areas of the trapezius muscles and the MEP latencies and amplitudes were compared between patients with and without neck pain.Results: The latency and amplitude of the control waveforms were not significantly different between groups. The neck pain group had a significantly shorter final waveform latency (neck pain: 23.6±2.5, no neck pain: 25.8±4.5; p =0.019) and significantly larger amplitude (neck pain: 2,125±1,077, no neck pain: 1,630±966; p =0.041) than the no neck pain group.Conclusions: Postoperative neck pain was associated with the final waveform latency and amplitude of the trapezius muscle MEPs during cervical laminoplasty. Intraoperative electrophysiological trapezius muscle abnormalities could cause postoperative neck pain.

Impact of the COVID-19 Pandemic on Adherence to Denosumab Therapy: A Single Center Study

Kobayashi Kazuyoshi,Sato Koji,Ando Toshihiro,Ando Kei,Imura Saori 대한척추외과학회 2023 Asian Spine Journal Vol.17 No.5

Study Design: A retrospective comparative study of denosumab therapy adherence before and during the coronavirus disease 2019 (COVID-19) pandemic.Purpose: To evaluate the effect of the COVID-19 pandemic on denosumab therapy adherence in Japan.Overview of Literature: Denosumab is a monoclonal antibody for osteoporosis treatment. Delayed denosumab injections are associated with reduced treatment responses, which was a concern during the COVID-19 pandemic.Methods: Participants included 376 patients who received denosumab (60 mg every 6 months) from January 2013 to June 2021. The time from therapy initiation to discontinuation was used to measure persistence, and that between initial and subsequent injections was used to determine adherence. The pandemic period was from March 2020 to December 2021.Results: Patients were divided into those treated after March 2020 (pandemic group, n=244) and those who discontinued treatment before March 2020 (non-pandemic group, n=132). Non-persistent cases accounted for 154, including 24 (20%), 64 (19%), and 66 (53%) aged ≤59 years, 60–79 years, and ≥80 years, respectively. The overall persistence rate at 78 months was 59.2%. Postponed cases were significantly lower in the non-pandemic group than in the pandemic group (8% vs. 15%, <i>p</i> =0.042). Postponement with a delay of 1–2 months did not significantly differ between the two groups, but with a significant difference for a delay of ≥3 months (0% vs. 36%, <i>p</i> =0.024).Conclusions: Denosumab adherence remained constant but postponed cases significantly increased during the COVID-19 pandemic. Better communication by health providers on denosumab adherence and alternative administration may reduce dosing interruptions in similar pandemic situations.

Variety of the Wave Change in Compound Muscle Action Potential in an Animal Model

Zenya Ito,Shiro Imagama,Kei Ando,Akio Muramoto,Kazuyoshi Kobayashi,Tetsuro Hida,Kenyu Ito,Yoshimoto Ishikawa,Mikito Tsushima,Akiyuki Matsumoto,Satoshi Tanaka,Masayoshi Morozumi,Yukihiro Matsuyama,Naok 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.6

Study Design: Animal study. Purpose: To review the present warning point criteria of the compound muscle action potential (CMAP) and investigate new criteria for spinal surgery safety using an animal model. Overview of Literature: Little is known about correlation palesis and amplitude of spinal cord monitoring. Methods: After laminectomy of the tenth thoracic spinal lamina, 2–140 g force was delivered to the spinal cord with a tension gage to create a bilateral contusion injury. The study morphology change of the CMAP wave and locomotor scale were evaluated for one month. Results: Four different types of wave morphology changes were observed: no change, amplitude decrease only, morphology change only, and amplitude and morphology change. Amplitude and morphology changed simultaneously and significantly as the injury force increased (p <0.05) Locomotor scale in the amplitude and morphology group worsened more than the other groups. Conclusions: Amplitude and morphology change of the CMAP wave exists and could be the key of the alarm point in CMAP.