Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Shiro Imagama x
  • By Author: Katayama, Yoshito x
Clear All Modify Search
Restricted access

Yukihiro Matsuyama, Yoshihito Sakai, Yoshito Katayama, Shiro Imagama, Zenya Ito, Norimitsu Wakao, Koji Sato, Mitsuhiro Kamiya, Yasutsugu Yukawa, Tokumi Kanemura, Makoto Yanase and Naoki Ishiguro

Object

The authors investigated the outcome of intramedullary spinal cord tumor surgery, focusing on the effect of preoperative neurological status on postoperative mobility and the extent of tumor excision guided by intraoperative spinal cord monitoring prospectively.

Methods

Intramedullary spinal cord tumor surgery was performed in 131 patients between 1997 and 2007. The authors compared the pre- and postoperative neurological status and examined the type of surgery in 106 of these patients. A modified McCormick Scale (Grades I–V) was used to assess ambulatory ability (I = normal ambulation; II = mild motor sensory deficit, independent without external aid; III = independent with external aid; IV = care required; and V = wheelchair required). The type of surgery was classified into 4 levels: total resection, subtotal resection, partial resection, and biopsy.

Results

The 106 patients consisted of 47 females and 59 males, whose average age was 42.5 years (range 6–75 years). The mean follow-up period was 7.3 years (range 2.5 months–21 years). The tumor types included astrocytoma (12 cases), ependymoma (46 cases), hemangioblastoma (16 cases), cavernous hemangioma (17 cases), and others (15 cases overall: gangliocytoma, 1; germ cell tumor, 1; lymphoma, 3; neurinoma, 1; meningioma, 1; oligodendroglioma, 1; sarcoidosis, 2; glioma, 1; and unknown, 4). Initial total excision, subtotal resection, partial resection, biopsy, and duraplasty were performed in 59, 12, 22, 12, and 1 patients, respectively. According to the preoperative McCormick Scale, ambulatory status was classified as Grades I, II, III, IV, and V in 41(38%), 30 (28%), 14 (13%), 19 (19%), and 2 (2%) patients, respectively. Thirty-three (31%) of 106 patients suffered postoperative neurological deterioration. The number of patients who did not lose ambulatory ability or who achieved an ambulatory status of Grade I or II postoperatively was 33 (80%), 21 (70%), 10 (71%), 8 (42%), and 1 (50%) in patients with preoperative Grades I, II, III, IV, and V, respectively. Total excision was performed in 31 (79%) of 39 patients with preoperative Grade I, 12 (40%) of 30 patients with Grade II, 7 (50%) of 14 patients with Grade III, and 9 of 21 patients (38%) with Grade IV or V, indicating that the rate of total excision was significantly higher in patients with Grade I status.

Conclusions

The postoperative ambulatory ability was excellent in patients with a good preoperative neurological status. Total excision in patients with Grade I or II ambulation was associated with a good prognosis for postoperative mobility. However, the rate of postoperative deterioration was 31.5%, which is relatively high, and patients should be fully informed of this concern prior to intramedullary spinal cord tumor surgery.

Restricted access

Shiro Imagama, Yukihiro Matsuyama, Yoshihito Sakai, Hiroshi Nakamura, Yoshito Katayama, Zenya Ito, Norimitsu Wakao, Koji Sato, Mitsuhiro Kamiya, Fumihiko Kato, Yasutsugu Yukawa, Yasushi Miura, Hisatake Yoshihara, Kazuhiro Suzuki, Kei Ando, Kenichi Hirano, Ryoji Tauchi, Akio Muramoto and Naoki Ishiguro

Object

The purpose of this study was to provide the first evidence for image classification of idiopathic spinal cord herniation (ISCH) in a multicenter study.

Methods

Twelve patients who underwent surgery for ISCH were identified, and preoperative symptoms, severity of paralysis and myelopathy, disease duration, plain radiographs, MR imaging and CT myelography findings, surgical procedure, intraoperative findings, data from spinal cord monitoring, and postoperative recovery were investigated in these patients. Findings on sagittal MR imaging and CT myelography were classified into 3 types: a kink type (Type K), a discontinuous type (Type D), and a protrusion type (Type P). Using axial images, the location of the hiatus was classified as either central (Type C) or lateral (Type L), and the laterality of the herniated spinal cord was classified based on correspondence (same; Type S) or noncorrespondence (opposite; Type O) with the hiatus location. A bone defect at the ISCH site and the laterality of the defect were also noted.

Results

Patients with Type P herniation had a good postoperative recovery, and those with a Type C location had significant severe preoperative lower-extremity paralysis and a significantly poor postoperative recovery. Patients with a bone defect had a significantly severe preoperative myelopathy, but showed no difference in postoperative recovery.

Conclusions

The authors' results showed that a Type C classification and a bone defect have strong relationships with severity of symptoms and surgical outcome and are important imaging and clinical features for ISCH. These findings may allow surgeons to determine the severity of preoperative symptoms and the probable surgical outcome from imaging.

Restricted access

Zenya Ito, Shiro Imagama, Yoshihito Sakai, Yoshito Katayama, Norimitsu Wakao, Kei Ando, Kenichi Hirano, Ryoji Tauchi, Akio Muramoto, Hany El Zahlawy, Yukihiro Matsuyama and Naoki Ishiguro

Object

The purpose of this study was to review the present criteria for the compound muscle action potential (CMAP) alert and for safe spinal surgery.

Methods

The authors conducted a retrospective study of 295 patients in whom spinal cord monitoring had been performed during spinal surgery. The waveforms observed during spinal surgery were divided into the following 4 grades: Grade 0, normal; Grade 1, amplitude decrease of 50% or more and latency delay of 10% or more; Grade 2, multiphase pattern; and Grade 3, loss of amplitude. Waveform grading, its relationship with postoperative motor deficit, and CMAP sensitivity and specificity were analyzed. Whenever any wave abnormality occurred, the surgeon was notified and the surgical procedures were temporarily suspended. If no improvements were seen, the surgery was terminated.

Results

Compound muscle action potential wave changes occurred in 38.6% of cases. With Grade 1 or 2 changes, no paresis was detected. Postoperative motor deficits were seen in 8 patients, all with Grade 3 waveform changes. Among the 287 patients without postoperative motor deficits, CMAP changes were not seen in 181, with a specificity of 63%. The false-positive rate was 37% (106 of 287). However, when a Grade 2 change was set as the alarm point, sensitivity was 100% and specificity was 79.4%. The false-positive rate was 20% (59 of 295).

Conclusions

Neither the Grade 1 nor the Grade 2 groups included patients who demonstrated a motor deficit. All pareses occurred in cases showing a Grade 3 change. Therefore, the authors propose a Grade 2 change (multiphasic waveform) as a new alarm point. With the application of this criterion, the false-positive rate can be reduced to 20%.