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Featured researches published by Toru Sasamori.


Neurosurgery | 2010

Incidence and Pathogenesis of Transient Cheiro-Oral Syndrome After Surgical Revascularization for Moyamoya Disease

Toru Sasamori; Satoshi Kuroda; Naoki Nakayama; Yoshinobu Iwasaki

BACKGROUND:There are no reports that denote transient cheiro-oral syndrome (COS) after surgical revascularization for moyamoya disease. OBJECTIVE:To clarify the incidence and pathogenesis of transient COS after surgical revascularization for moyamoya disease. METHODS:This study included 21 patients who underwent superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and indirect bypass because of Moyamoya disease. Their medical records were evaluated to identify clinical features of postoperative transient COS. The findings on MRI, magnetic resonance angiography, and single-photon emission computed tomography were also analyzed. RESULTS:Transient COS developed in 8 (22.9%) of 35 operated hemispheres, or in 6 (28.6%) of 21 patients between 3 and 20 days after surgery. Most of the COS were associated with mild weakness of the ipsilateral face and hand. Simultaneous radiological studies detected no findings of cerebral infarct or postoperative hyperperfusion. STA-MCA anastomosis was patent in all patients. However, their disease stage more frequently progressed owing to considerable blood flow via STA-MCA anastomosis, and basal moyamoya vessels disappeared or diminished in patients with transient COS rather than in those without. CONCLUSION:Transient COS after surgical revascularization for moyamoya disease is not rare. Bypass flow through STA-MCA anastomosis may stimulate a rapid progression of disease stage and diminish basal moyamoya vessels, causing transient COS within 3 weeks after surgery.


Neurologia Medico-chirurgica | 2014

Neurovascular bundle decompression without excessive dissection for tarsal tunnel syndrome.

Kyongsong Kim; Toyohiko Isu; Daijiro Morimoto; Toru Sasamori; Atsushi Sugawara; Yasuhiro Chiba; Masahiro Isobe; Shiro Kobayashi; Akio Morita

Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the posterior tibial nerve and its branches in the tarsal tunnel. We present our less invasive surgical treatment of TTS in 69 patients (116 feet) and their clinical outcomes. The mean follow-up period was 64.6 months. With the patient under local anesthesia we use a microscope to perform sharp dissection of the flexor retinaculum and remove the connective tissues surrounding the posterior tibial nerve and vessels. To prevent postoperative adhesion and delayed neuropathy, decompression is performed to achieve symptom improvement without excessive dissection. Decompression is considered complete when the patient reports intraoperative symptom abatement and arterial pulsation is sufficient. The sensation of numbness and/or pain and of foreign substance adhesion was reduced in 92% and 95% of our patients, respectively. In self-assessments, 47 patients (68%) reported the treatment outcome as satisfactory, 15 (22%) as acceptable, and 7 (10%) were dissatisfied. Of 116 feet, 4 (3%) required re-operation, initial decompression was insufficient in 2 feet and further decompression was performed; in the other 2 feet improvement was achieved by decompression of the distal tarsal tunnel. Our surgical method involves neurovascular bundle decompression to obtain sufficient arterial pulsation. As we use local anesthesia, we can confirm symptom improvement intraoperatively, thereby avoiding unnecessary excessive dissection. Our method is simple, safe, and without detailed nerve dissection and it prevents postoperative adhesion.


Asian Spine Journal | 2016

Clinical Factors for Prognosis and Treatment Guidance of Spinal Cord Astrocytoma

Toshitaka Seki; Kazutoshi Hida; Shunsuke Yano; Takeshi Aoyama; Izumi Koyanagi; Toru Sasamori; Shuji Hamauch; Kiyohiro Houkin

Study Design Retrospective study. Purpose To obtain information useful in establishing treatment guidelines by evaluating baseline clinical features and treatment outcomes of patients with spinal cord astrocytoma (SCA). Overview of Literature The optimal management of SCA remains controversial, and there are no standard guidelines. Methods The study included 20 patients with low-grade and 13 with high-grade SCA surgically treated between 1989 and 2014. Patients were classified according to the extent of surgical resection. Survival was assessed using Kaplan–Meier plots and compared between groups by log-rank tests. Neurological status was defined by the modified McCormick scale and compared between groups by Mann–Whitney U tests. Results Surgical resection was performed for 19 of 20 low-grade (95%) and 10 of 13 high-grade (76.9%) SCA patients. Only nine patients (27.3%) underwent gross total resection, all of whom had low-grade SCA. Of all patients, 51.5% showed deteriorated neurological status compared to preoperative baseline. Median overall survival was significantly longer for low-grade SCA than that (91 months, 78% at 5 years vs. 15 months, 31% at 5 years; p=0.007). Low-grade SCA patients benefited from more aggressive resection, whereas high-grade SCA patients did not. Multivariate analysis revealed histology status (hazard ratio [HR], 0.30; 95% confidence interval [CI], 0.09–0.98; p<0.05) and postoperative neurological status (HR, 0.12; CI, 0.02–0.95; p<0.05) as independent predictors of longer overall survival. Adjuvant radiotherapy had no significant impact on survival rate. However, a trend for increased survival was observed with radiation cordotomy (RCT) in high-grade SCA patients. Conclusions Aggressive resection for low-grade and RCT may prolong survival. Preservation of neurological status is an important treatment goal. Given the low incidence of SCA, establishing strong collaborative, interdisciplinary, and multi-institutional study groups is necessary to define optimal treatments.


Asian Spine Journal | 2016

Surgical Outcome of Children and Adolescents with Tethered Cord Syndrome

Toshitaka Seki; Kazutoshi Hida; Shunsuke Yano; Toru Sasamori; Shuji Hamauch; Izumi Koyanagi; Kiyohiro Houkin

Study Design Retrospective cohort study. Purpose To compare long-term results of surgery with the outcomes of symptomatic and asymptomatic tethered cord syndrome (TCS) in children and adolescents and to assess the surgery duration for those with TCS. Overview of Literature Pediatric patients with TCS continue to pose significant diagnostic and management challenges. Methods We retrospectively analyzed the outcomes of 31 patients (16 males, 15 females) with TCS, including 21 with lumbosacral lipoma. All were surgically treated between 1989 and 2015. They were divided into symptomatic and asymptomatic TCS groups. The results of the treatment were summarized and analyzed using a non-parametric Mann–Whitney U test. Results Nineteen patients had symptomatic TCS and 12 had asymptomatic TCS. Patients had a median age of 34 months (range, 0–201 months). The median follow-up period was 116 months (range, 7–223 months). Of the 19 symptomatic TCS patients, preoperative deficits improved after surgery in two (10.5%) and remained stable in 17 (89.5%) patients. One of the 12 asymptomatic TCS (8.3%) patients showed an exacerbated illness after surgery, and one in 11 patients remained stable (11.7%). There were significant differences in monthly age at surgery, preoperative bowel and bladder dysfunction, neurological function, presence/absence of clean intermittent catheterization introduction, and presence/absence of motor disorder at final follow-up (all p<0.05). In the univariate analysis, the presence/absence of preoperative bowel and bladder dysfunction, and symptoms were strongly associated with the risk of children and adolescents with TCS (p<0.05). Conclusions Early accurate diagnosis and adequate surgical release might lead to successful outcomes in children and adolescents with TCS. Surgical untethering is a safe and effective method for treatment of children with TCS.


Journal of Neurology | 2014

Usefulness of 11C-methionine-positron emission tomography for the diagnosis of progressive multifocal leukoencephalopathy.

Shinichi Shirai; Ichiro Yabe; Takahiro Kano; Yuka Shimizu; Toru Sasamori; Kazunori Sato; Makoto Hirotani; Takayuki Nonaka; Ikuko Takahashi; Masaaki Matsushima; Naoya Minami; Kazuo Nakamichi; Masayuki Saijo; Kanako C. Hatanaka; Tohru Shiga; Shinya Tanaka; Hidenao Sasaki

Progressive multifocal leukoencephalopathy (PML) is a subacute demyelinating disease of the brain caused by the JC virus that occurs mainly in immunocompromised patients. The prognosis is very poor. As the lesion looks like non- specific leukoencephalopathy, making a diagnosis at the early stage is very difficult. We report three PML cases in which there was a mismatch between 11C-methionine-positron emission tomography (MET-PET) uptake and 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) uptake. All three cases demonstrated the hyper-uptake of MET around the white matter lesions and hypo-uptake of FDG inside the lesions. We speculate that the infection had ended inside the white matter lesions of these patients, while JC virus infection was ongoing around the lesions, resulting in the increase of methionine metabolism, and the glucose metabolism was reduced or intermediate because inflammatory cells infiltrate PML lesions rarely. Two patients who were diagnosed and treated with mefloquine while the JC virus was at a low level in the cerebrospinal fluid are still alive. We suggest the usefulness of MET-PET for the early diagnosis of PML and early treatment with mefloquine.


Journal of Neurosurgery | 2016

Development of a nonintermediate-incision ventriculoperitoneal shunt procedure using a nasogastric feeding tube for infant patients with hydrocephalus: technical note

Shuji Hamauchi; Toshitaka Seki; Toru Sasamori; Kiyohiro Houkin

Intermediate incisions are considered necessary to pass a catheter tube from the head to the abdomen in ventriculo-peritoneal (VP) shunting via a frontal bur hole. However, an intermediate incision can sometimes become dehiscent, resulting in CSF leakage or infection of the shunt system in the early period after shunt implantation, particularly in infant patients. In this article, the authors describe a novel method of VP shunt insertion that does not require an intermediate incision. This nonintermediate-incision VP shunt procedure was performed in 3 infant patients with hydrocephalus and was not associated with any complications. This method can eliminate the intermediate incision, which is a disadvantage of VP shunt insertion via a frontal bur hole.


Neurosurgery | 2016

In Reply: A Survey of Chronic Pain Due to Spinal Dural Arteriovenous Fistulae.

Toru Sasamori; Kazutoshi Hida; Toshiya Osanai; Shunsuke Yano; Toshitaka Seki; Kiyohiro Houkin

In Reply: A Survey of Chronic Pain Due to Spinal Dural Arteriovenous Fistulae We greatly appreciate the interest in our recent article and the thoughtful comments by Dr Rosenberg. Neurosurgeons may be less concerned with postoperative pain than other symptoms such as gait disturbance and micturition disorders in patients with spinal dural arteriovenous fistulae (SDAVFs). In fact, fewer studies have addressed chronic pain than gait disturbance and/or micturition disorders in patients with SDAVFs. Although the goal of neurosurgical SDAVF treatment is often the disconnection of the fistula, the issue of postoperative chronic leg pain must not be ignored, and active intervention to address this issue is necessary with respect to the quality of life of operated patients.


Clinical Imaging | 2014

A case of cervical juxtafacet cyst with extensive rim enhancement on Gd-DTPA MRI

Toru Sasamori; Kazutoshi Hida; Kimio Anzai; Shunsuke Yano; Yasutaka Kato; Shinya Tanaka; Hisatoshi Saito; Kiyohiro Houkin

The authors reported a case of cervical juxtafacet cyst with extensive rim enhancement on gadolinium-diethylenetriamine pentaacid magnetic resonance imaging. Operative finding revealed the epidural space around the mass filled with abundant venous plexus. Histological examination demonstrated that cyst wall was composed of the well-vascularized fibrous connective tissue with some inflammatory changes. We speculate that extensive rim enhancement of juxtafacet cyst may be attributed not only to the chronic inflammatory changes of cyst wall, but to engorged venous plexus within the widened epidural space.


Neurologia Medico-chirurgica | 2008

Cervical Perimedullary Arteriovenous Fistula in an Infant Presenting With Subarachnoid Hemorrhage

Toru Sasamori; Kazutoshi Hida; Shunsuke Yano; Takeshi Asano; Yoshinobu Iwasaki


No shinkei geka. Neurological surgery | 2009

[Assessing the treatment for sacroiliac joint dysfunction, piriformis syndrome and tarsal tunnel syndrome associated with lumbar degenerative disease].

Morimoto D; Toyohiko Isu; Shimoda Y; Shuji Hamauchi; Toru Sasamori; Sugawara A; Kim K; Matsumoto R; Isobe M

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