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.

Step-by-Step Sublaminar Approach With a Newly-Designed Spinal Endoscope for Unilateral-Approach Bilateral Decompression in Spinal Stenosis

Fujio Ito,Zenya Ito,Motohide Shibayama,Shu Nakamura,Minoru Yamada,Hideki Yoshimatu,Mikinobu Takeuchi,Kenzo Shimizu,Yasushi Miura 대한척추신경외과학회 2019 Neurospine Vol.16 No.1

Objective: Spinal stenosis is increasingly common due to population aging. In elderly patients with lumbar central canal stenosis (LCCS), minimizing muscle damage and bone resection is particularly important. We performed a step-by-step operation with a newly designed spinal endoscope to obtain adequate decompression in patients with spinal stenosis. Methods: From April 2015 to August 2016, 78 patients (48 males, 30 females) with LCCS (91 segments) underwent endoscopic decompression using a newly designed endoscope system. The inclusion criteria were: (1) neurogenic intermittent claudication with or without radiculopathy, (2) LCCS, and (3) having exhausted conservative treatment (>3 months). The exclusion criteria were: (1) >10° of instability, (2) spondylolisthesis grade II or greater according to the Meyerding criteria, (3) foraminal stenosis, (4) vascular intermittent claudication, (5) infection, and (6) stenosis combined with malignancy. We performed a step-by-step procedure using a newly designed endoscope system for unilateral-approach bilateral decompression. We used the same incision for 2–3 segments, only moving the skin. Results: The mean follow-up was 2.3±1.3 years. Excellent or good results were found according to the MacNab criteria in 85.9% of cases (67 of 78). The visual analogue scale, Japanese Orthopedic Association score, and Oswestry Disability Index showed significant decreases at 1 month, persisting until the 2-year follow-up. Dural tear occurred in 4 cases (5.1%), and patch repair was performed under endoscopy. No patients experienced aggravated instability requiring surgery. Conclusion: We obtained good results with endoscopic decompression surgery using a newly designed instrument that minimized muscle and bone damage in elderly patients with spinal stenosis.

Methods and Early Clinical Results of Percutaneous Lumbar Interbody Fusion

Shu Nakamura,Fjio Ito,Zenya Ito,Motohide Shibayama 대한척추신경외과학회 2020 Neurospine Vol.17 No.4

Objective: Percutaneous lumbar interbody fusion (PELIF) is a procedure that includes the use of new devices, which allow minimally invasive diskectomy under the percutaneous full-endoscopic guidance and safe percutaneous insertion of a standard-sized cage. This procedure can be applied to severe disk degeneration, spondylolisthesis, and all lumbar intervertebral levels including the L5–S1 level. We report the methods and the clinical outcomes of this procedure. Methods: Percutaneous diskectomy was performed with an outer sheath cutter and other devices. A cage was inserted with an L-shaped retract-slider. Hybrid facet screw fixation was performed for severe disk degeneration without spondylolisthesis. Conventional percutaneous pedicle screw fixation was performed for spondylolisthesis. The subjects consisted of 21 patients, who underwent PELIF and were followed up for 1 year or longer. Results: No complications related to cage insertion were detected. The mean visual analogue scale scores were improved from 6.1 to 1.9 for lower back pain in severe disc degeneration cases without spondylolisthesis, and from 7.6 to 1.0 for lower extremity symptoms in spondylolisthesis cases. Conclusion: The clinical outcomes were favorable. PELIF was found to be a minimally invasive method that did not compromise safety and efficiency. PELIF is a possible therapeutic option that should be considered for not only spondylolisthesis at various intervertebral levels but also for severe disk degeneration because of its minimal invasiveness.

Utility of a Computed Tomography-Based Navigation System (O-Arm) for En Bloc Partial Vertebrectomy for Lung Cancer Adjacent to the Thoracic Spine: Technical Case Report

Kazuyoshi Kobayashi,Shiro Imagama,Zenya Ito,Kei Ando,Kohei Yokoi,Naoki Ishiguro 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.2

We describe successful vertebrectomy from a posterior approach using a computed tomography (CT)-based navigation system (O-arm) in a 53-year-old man with adenocarcinoma of the posterior apex of the right lung with invasion of the adjacent rib, thoracic wall, and T2 and T3 vertebral bodies. En bloc partial vertebrectomy for lung cancer adjacent to the thoracic spine was planned using O-arm. First, laminectomy was performed from right T2 to T3, and pedicles and transverse processes of T2 to T3 were resected. O-arm was used to confirm the location of the cutting edge in the T2 to 3 right vertebral internal body, and osteotomy to the anterior cortex was performed with a chisel. Next, the patient was placed in a left decubitus position. The surgical specimen was extracted en bloc . This case shows that O-arm can be used reliably and easily in vertebrectomy from a posterior approach and can facilitate en bloc resection.

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.

Spinal Metastasis from Struma Ovarii: Case Report and Review of the Literature

Kazuyoshi Kobayashi,Shiro Imagama,Shin Tsunekawa,Kaori Hosokawa,Minemori Watanabe,Zenya Ito,Kei Ando,Naoki Ishiguro 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.2

Struma ovarii is a rare tumor that is defined as an ovarian teratoma with a thyroid tissue component exceeding 50%. Most of these tumors are benign, with malignant struma ovarii occurring in <1% of patients. Here, we describe the case of a 49-year-old female patient with malignant struma ovarii who developed thoracic spine metastasis. She had undergone an oophorectomy and was diagnosed with struma ovarii 10 years previously. She had remained recurrence-free thereafter. At 49 years of age, she developed low back pain and was admitted to our hospital for evaluation of a spinal tumor at the Th7 level. An emergency bone biopsy led to a diagnosis of metastasis from malignant struma ovarii. External beam radiotherapy inhibited further tumor growth and there was no resulting muscle weakness. This is the first report of spinal metastasis occurring 10 years after resection of struma ovarii, indicating the need for long-term follow-up.