Masaki Yoshimura

Osaka City General Hospital, Ōsaka, Ōsaka, Japan

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Publications (15)6.29 Total impact

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    ABSTRACT: Objective: Spontaneous cerebrospinal fluid rhinorrhea associated with aqueductal stenosis is rare. CSF diversion is reported to be a failure in the majority of cases. The combination of the repair of the skull base and CSF diversion is reported to be successful. We describe a case successfully treated by intradural repair with ventricular drainage followed by endoscopic third ventriculostomy. Clinical presentation: A 28-year-old woman presented with rhinorrhea, and occasional attacks of headache, vomiting, and unconsciousness for two years. She had been diagnosed as arrested hydrocephalus for 10 years. Magnetic resonance imaging revealed triventriculomegaly with ballooning of the floor of the third ventricle, tonsilar herniation, right anterior horn herniation into the cribriform plate, and bilateral temporal lobe herniation into the temporal base. Intervention: A ventricular drain was inserted followed by dissection of the herniated brain and repair of the enlarged cribriform foramen with periosteal flap. Make sure that the bacterial culture negative, endoscopic third ventriculostomy has been performed. There is no recurrence of hydrocephalus and rhinorrhea for two years. Conclusion: Direct communication between the lateral ventricle and the nasal/paranasal sinus is a rare complication of aqueductal stenosis and LOVA. Surgical repair of the skull base followed by cerebrospinal fluid diversion with endoscopic third ventriculostomy was a safe and reliable method.
    No shinkei geka. Neurological surgery 10/2012; 40(10):897-902. · 0.13 Impact Factor
  • Masaki Yoshimura · Yoshinori Uchiyama · Yoshiyasu Iwai ·

    Higher Brain Function Research 01/2012; 32(2):320-327. DOI:10.2496/hbfr.32.320
  • Yoshiyasu Iwai · Masaki Yoshimura · Aiko Terada · Kazuhiro Yamanaka · Naomi Koshimo ·
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    ABSTRACT: We reviewed results of the surgical outcome of pituitary tumors treated via the transsphenoidal approach between January, 1994 and January, 2010 at our institution. This data included 100 patients (124 procedures) treated through the sublabial transsphenoidal approach and 45 patients (54 procedures) treated through the endoscopic endonasal (bilateral nostrils) transsphenoidal approach performed by a single surgeon. The extent of tumor removal was significantly improved with endoscopic surgery; adjuvant gamma knife radiosurgery was needed for 65% of patients undergoing microsurgery vs. 30% for patients who had endoscopic surgery (p<0.0001). Patients who underwent endoscopic surgery had less intraoperative blood loss (mean volume: 100 mL for microsurgery patients vs. 30 mL for endoscopic surgery patients, p<0.0001), less pain, and less need for postoperative hormone replacement therapy (19% for microsurgery patients vs. 6% for endoscopic surgery patients; p<0.05). CSF leakage and meningitis were experienced in one microsurgery patient (1%) and one endoscopic surgery patient (2.2%). Endoscopic surgery is a reasonable alternative to microsurgery and our experience supports the concept that an otolaryngologist/neurosurgeon team skilled in endoscopic techniques and pituitary surgery can safely make the transition from microsurgery to endoscopic surgery.
    No shinkei geka. Neurological surgery 02/2011; 39(2):141-7. · 0.13 Impact Factor
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    ABSTRACT: We report the case of a 64-year-old woman with cystic meningioma; this patients was otherwise healthy and experienced formed visual hallucinations after excision of the tumor. She experienced diplopia associated with metamorphopsia, which had persisted for 5 years only when she laid down and turned on her left side. After the excision of the convexity meningioma located in the right temporoparietal lobe, she experienced several types of formed visual hallucinations such as closet-like pictures, flowers sketched on stones, falling maple-like leaves, and moving or wriggling dwarves. She was alert and her visual field was normal; further, she did not experience delirium or seizures. She experienced these hallucinations only when she closed her eyes; these hallucinations persisted for 3 days after the operation. The patient illustrated her observations with beautiful sketches, and the mechanism of visual hallucinations was studied.
    Brain and nerve = Shinkei kenkyū no shinpo 08/2010; 62(8):893-7.
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    ABSTRACT: We evaluated the endocrinological outcomes of gamma knife radiosurgery (GKS) for the treatment of growth hormone (GH)-producing pituitary adenomas. Twenty-six patients treated with GKS (median treatment [tumour] volume: 0.8 mL; median marginal radiation dose: 20Gy) were followed for a median of 84 months. "Disease remission" was defined as either nadir levels of GH <1 microg/L during an oral glucose load, or random GH levels <2 microg/L and normal age-adjusted and sex-adjusted levels of insulin-like growth factor without pituitary suppressive medications. The remission rate was 38% (10/26) and the 5-year and 10-year actuarial remission rates were 16.9% and 47.4%, respectively. Two patients (8%) suffered hypopituitarism requiring medication, but no other serious deficits were observed. Although GKS requires a relatively long time to achieve hormonal remission, it is a very useful, long-term treatment for GH-producing adenomas. We propose that compared to continuing life-long medication, GKS is less invasive and more cost effective.
    Journal of Clinical Neuroscience 03/2010; 17(3):299-304. DOI:10.1016/j.jocn.2009.05.040 · 1.38 Impact Factor

  • Surgery for Cerebral Stroke 01/2010; 38(5):308-312. DOI:10.2335/scs.38.308
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    ABSTRACT: To report our experiences in the treatment for intracranial arteriovenous shunts (AV shunts) in the pediatric population. Twelve children with intracranial AV shunts were treated with endovascular embolization between December 1993 and March 2008. These comprised two cases of vein of Galen aneurysmal malformation, three of dural sinus malformation, two of infantile dural AV shunt, five of pial AV fistula including two of vein of Galen aneurysmal dilatation. There were eleven boys and one girl. The age at the first embolization ranged from day 0 to 9 years. We reviewed their clinical features and outcomes. Six patients including four neonates presented with congestive heart failure, one infant with macrocrania and three children with headache, seizure or ataxia. The number of endovascular embolization ranged from one to five per patient. These included eighteen transarterial embolizations and ten transvenous embolizations. All patients except for one who died eventually from pulmonary hemorrhage showed improvement in their symptoms. Although only five patients achieved complete occlusion of AV shunts, six patients including them developed normally. Intracranial AV shunts in the pediatric population present characteristic clinical features depending on the age of the presentation. Endovascular embolization is currently the treatment of choice for them. It is more important to obtain normal development than to achieve normal morphological appearance. It is also important to understand the difference of pathophysiological features of these diseases in the pediatric and adult population.
    No shinkei geka. Neurological surgery 07/2009; 37(6):543-50. · 0.13 Impact Factor

  • 01/2009; 3(3):198-202. DOI:10.5797/jnet.3.198
  • Yoshiyasu Iwai · Kazuhiro Yamanaka · Masaki Yoshimura ·
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    ABSTRACT: A 37-year-old man was treated for lung cancer by chemo-radiation therapy. Subsequently, magnetic resonance (MR) imaging identified a ring-enhanced lesion in the left temporal lobe. Gamma knife radiosurgery was performed under a diagnosis of brain metastasis. Nevertheless, MR imaging showed regrowth of the tumor 1 year later, so radiosurgery was repeated on the same lesion. Two years after the first radiosurgery, MR imaging revealed an irregularly enhanced lesion with increasing perifocal edema in the left temporal lobe. Emergency surgery was performed under a diagnosis of impending uncal herniation. The histological diagnosis was cavernous malformation. This case demonstrates that gamma knife radiosurgery can cause radiation-induced cavernous malformation.
    Neurologia medico-chirurgica 05/2007; 47(4):171-3. DOI:10.2176/nmc.47.171 · 0.72 Impact Factor
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    ABSTRACT: A CTO of the intracranial ICA is usually managed medically and rarely by EC-IC bypass in selected patients. Percutaneous transluminal angioplasty has not been used. A 73-year-old man presented with frequent temporary blindness of the left eye and dizziness due to thrombotic occlusion of the left intracranial ICA, causing hemodynamic compromise. This patient was successfully treated by percutaneous angioplasty (balloon angioplasty and stent placement) under proximal balloon protection at 7 weeks from the ictus. Ischemic symptoms had not recurred during the 6-month follow-up period. Percutaneous angioplasty for a CTO of the intracranial ICA is technically feasible and can be an alternative to EC-IC bypass in a selected group of patients with symptomatic hemodynamic compromise, which is refractory to the best medical treatment.
    Surgical Neurology 12/2006; 66(5):513-8; discussion 518. DOI:10.1016/j.surneu.2006.02.037 · 1.67 Impact Factor

  • Surgery for Cerebral Stroke 01/2006; 34(4):252-256. DOI:10.2335/scs.34.252
  • Yoshiyasu Iwai · Kazuhiro Yamanaka · Masaki Yoshimura ·
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    ABSTRACT: We evaluated the efficacy of gamma knife radiosurgery for cavernous sinus metastases and invasion. We treated and followed up 21 patients with cavernous sinus metastases and invasion using gamma knife radiosurgery. Nine of these patients had nasopharyngeal cancer, and 12 had distant metastases from other cancers. The volume of tumors ranged from 2.9 to 50.0 (median 9.9) mL. and the radiation dose to the tumor margin was 10 to 21 (median 14) Gy. The median follow-up period was 9 months. Clinical symptoms were improved in 48% of the patients after treatment, and tumor growth control was obtained in 67% of the patients at their final follow-up. The actual 1- and 2-year tumor growth control rates were 68% and 43%, respectively. The mean survival time was 13 months. No patient had radiation injury. Gamma knife radiosurgery is a very useful therapeutic option for the treatment of cavernous sinus metastases and invasion, either as initial treatment or as an adjunct treatment for recurrences even in preirradiated patients.
    Surgical Neurology 12/2005; 64(5):406-10; discussion 410. DOI:10.1016/j.surneu.2004.12.021 · 1.67 Impact Factor
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    ABSTRACT: We report a 13-year-old boy who presented with acute basilar artery occlusion due to traumatic arterial dissection. Because a grave prognosis was expected if left untreated, and the chance of neurological recovery was believed to be unlikely but not zero, given that emergency stenting for the dissection was performed within 6 h of ictus. Recanalization of the basilar artery with stent placement did not change the poor prognosis in this patient because there was extension of dissection into the posterior cerebral arteries.
    Pediatric Neurosurgery 11/2005; 41(6):318-22. DOI:10.1159/000088734 · 0.33 Impact Factor
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    ABSTRACT: We evaluated the treatment results of nonfunctioning pituitary adenomas in the era of radiosurgery. Between January 1994 and December 2003, we operated on 44 patients with nonfunctioning pituitary adenomas. 43 patients were operated on by transsphenoidal surgery and one patient was operated on by the transcranial approach. Total removal was able to be achieved in 13 patients (30%). Gamma knife radiosurgery was performed for residual tumor in 26 patients and for recurrence in 2 patients. The mean tumor diameter at the gamma knife radiosurgery was 18.2 mm (7.9 to 26.3 mm). The treatment dose was a mean of 12.3 Gy (8 to 16 Gy) to the tumor margin. The mean follow-up period after radiosurgery was 36.4 months. Tumor growth control was able to be achieved in 26 patients (93%). Two patients (7%) required adrenal and thyroid hormonal replacement during the follow-up period after radiosurgery due to radiation-induced endocrinopathy. None of the patients suffered from new cranial nerve deficits. This included optic neuropathy. Surgical resection using transsphenoidal surgery and subsequent gamma knife radiosurgery for residual and recurrent tumor proved to have a highly effective tumor growth control rate, and maintained the quality of life in patients with nonfunctioning pituitary adenomas.
    No shinkei geka. Neurological surgery 09/2005; 33(8):777-83. · 0.13 Impact Factor
  • A. Nishio · M. Yoshimura · M. Hara · M. Komiyama ·

    12/2003; 16(6):1277-1282. DOI:10.1177/197140090301600666