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
The purpose of this study was to provide the first evidence for image classification of idiopathic spinal cord herniation (ISCH) in a multicenter study.
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.
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.
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.
Ryoji Tauchi, Shiro Imagama, Hidefumi Inoh, Yasutsugu Yukawa, Tokumi Kanemura, Koji Sato, Yoshihito Sakai, Mitsuhiro Kamiya, Hisatake Yoshihara, Zenya Ito, Kei Ando, Akio Muramoto, Hiroki Matsui, Tomohiro Matsumoto, Junichi Ukai, Kazuyoshi Kobayashi, Ryuichi Shinjo, Hiroaki Nakashima, Masayoshi Morozumi and Naoki Ishiguro
Cervical spondylosis that causes upper-extremity muscle atrophy without gait disturbance is called cervical spondylotic amyotrophy (CSA). The distal type of CSA is characterized by weakness of the hand muscles. In this retrospective analysis, the authors describe the clinical features of the distal type of CSA and evaluate the results of surgical treatment.
The authors performed a retrospective review of 17 consecutive cases involving 16 men and 1 woman (mean age 56.3 years) who underwent surgical treatment for the distal type of CSA. The condition was diagnosed on the basis of cervical spondylosis in the presence of muscle impairment of the upper extremity (intrinsic muscle and/or finger extension muscles) without gait disturbance, and the presence of a compressive lesion involving the anterior horn of the spinal cord, the nerve root at the foramen, or both sites as seen on axial and sagittal views of MRI or CT myelography. The authors assessed spinal cord or nerve root impingement by MRI or CT myelography and evaluated surgical outcomes.
The preoperative duration of symptoms averaged 11.8 months. There were 14 patients with impingement of the anterior horn of the spinal cord and 3 patients with both anterior horn and nerve root impingement. Twelve patients were treated with laminoplasty (plus foraminotomy in 1 case), 3 patients were treated with anterior cervical discectomy and fusion, and 2 patients were treated with posterior spinal fixation. The mean manual muscle testing grade was 2.4 (range 1–4) preoperatively and 3.4 (range 1–5) postoperatively. The surgical results were excellent in 7 patients, good in 2, and fair in 8.
Most of the patients in this series of cases of the distal type of CSA suffered from impingement of the anterior horn of the spinal cord, and surgical outcome was fair in about half of the cases.