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  • Author or Editor: Kenichi Sato x
  • Journal of Neurosurgery: Spine x
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Kenichi Sato, Karel G. TerBrugge and Timo Krings

Object

Spinal dural arteriovenous fistulas (SDAVFs) consist of a shunt with converging feeding vessels arising from radiculomeningeal arteries and draining retrogradely via a radicular vein into the perimedullary veins, thereby causing progressive myelopathy due to venous hypertension in the spinal cord. The purpose of this study was to evaluate the hypothesis that the obstruction of radicular venous outlets could be an additional factor inducing symptomatic venous hypertension due to a decreased outflow in SDAVFs.

Methods

The authors compared the clinical and imaging findings in patients with asymptomatic SDAVFs identified incidentally at the upper thoracic region with the findings in symptomatic patients who harbored SDAVFs at the same level.

Results

All symptomatic patients presented with medullary dysfunction. The mean age of patients with asymptomatic SDAVF was 51.5 years, approximately 10 years younger than the patients with symptomatic SDAVF (64.1 years old). Despite the existence of dilated perimedullary vessels in the dorsal side of the spinal cord in all patients, the spinal cord edema seen in symptomatic patients was not detected on the MR images obtained in patients with asymptomatic SDAVF. The spinal angiograms of the asymptomatic patients distinctively demonstrated early radicular venous outflow from affected perimedullary veins to the extradural venous plexus as a potential alternate route for the venous hypertension to be released.

Conclusions

Obstruction of the radicular venous outflow could be an important factor in inducing spinal congestive edema due to venous hypertension, as well as subsequent clinical symptoms of SDAVFs.

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Takumi Kajitani, Toshiki Endo, Tomoo Inoue, Kenichi Sato, Yasushi Matsumoto and Teiji Tominaga

The authors report the case of a 70-year-old woman with lumbar spinal epidural arteriovenous fistula (SEDAVF) who experienced subarachnoid hemorrhage (SAH) after a diagnostic lumbar puncture. According to the literature, perimedullary spinal vein enlargement is a hallmark of spinal vascular diseases; however, there are certain cases in which routine sagittal MRI fails to disclose signal flow voids. In such cases, patients may undergo a lumbar tap to investigate the possible causes of spinal inflammatory or demyelinating disease. Recognizing this phenomenon is essential because lumbar puncture of the epidural venous pouch or an enlarged intradural vein in SEDAVF may induce severe SAH. A high clinical index of suspicion can prevent similar cases in lumbar SEDAVF.

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Kei Ando, Shiro Imagama, Norimitsu Wakao, Kenichi Hirano, Ryoji Tauchi, Akio Muramoto, Fumihiko Kato, Yasutsugu Yukawa, Noriaki Kawakami, Koji Sato, Yuji Matsubara, Tokumi Kanemura, Yukihiro Matsuyama and Naoki Ishiguro

Object

The purpose of this study was to provide the first evidence for the influence of an ossified anterior longitudinal ligament (OALL) on the clinical features and surgical outcomes in an ossified ligamentum flavum (OLF) in the thoracic region.

Methods

Sixty-three patients who underwent surgery for a 1-level thoracic OLF were identified, and preoperative symptoms, severity of symptoms and myelopathy, disease duration, MR imaging and CT findings, surgical procedure, intraoperative findings, complications, and postoperative recovery were investigated in these patients. Entities of OALLs were found on sagittal CT images to be adjacent to or at the same vertebral level as the OLF were classified into 4 types: no discernible type (Type N), one-sided (Type O), discontinuous (Type D), and continuous (Type C).

Results

The duration of symptoms was especially long for Types D and C OALLs. Patients with Type D OALLs had a significantly worse percentage of recovery, as well as worse preoperative JOA scores.

Conclusions

The authors' results showed that a Type D OALL had strong associations with preoperative severity of symptoms and surgical outcomes. These findings may allow surgeons to determine the severity of preoperative symptoms and the probable surgical outcomes from the OALL classifications. Moreover, surgery with instrumentation for Type D OALLs may produce better surgical outcomes.

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Ayumi Narisawa, Toshiki Endo, Kenichi Sato, Mika Watanabe, Akira Takahashi and Teiji Tominaga

The authors report on a 49-year-old man with a thoracic spinal dural arteriovenous shunt (dAVS) in which rupture of a varix caused intramedullary hemorrhage. In the literature, patients with a thoracic dAVS predominantly present with congestive myelopathy; however, the patient featured in this report presented without increased deep tendon reflexes or muscle weakness, but instead with intermittent stabbing chest pain and paresthesia. Magnetic resonance images and angiograms demonstrated tortuous enlargement and the formation of a varix-like structure of the draining veins, features compatible with those of high-flow angiopathy. Recognition of this phenomenon is important in thoracic dAVS because intramedullary hemorrhage dramatically degrades outcome. A high index of clinical suspicion can prevent a similar case of thoracic dAVS from progressing to intramedullary hemorrhage.

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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.