Hiroyuki Masaoka

National Defense Medical College, Tokorozawa, Saitama-ken, Japan

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Publications (77)101.29 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of the present study was to investigate the risk factors for hydrocephalus after decompressive craniectomy (DC) for hemispheric cerebral infarction. This study selected 28 patients who underwent DC for malignant hemispheric cerebral infarction. The patients' clinical and radiologic findings were retrospectively reviewed. Fourteen of the 28 patients were male and 14 were female, with an age range from 34 to 80years (mean, 63.5years). Eighteen patients (64.3%) underwent DC within 48hours of stroke onset. The superior limit of DC was <25mm from the midline in 16 patients (57.1%). Twenty-two patients underwent cranioplasty, and the interval from DC to cranioplasty was within 60days in 14 patients. Pre- and post-cranioplasty hydrocephalus were observed in 13 and nine patients, respectively. Two patients required shunt procedures for post-cranioplasty hydrocephalus. Patients with DC whose superior limit was <25mm from the midline had a significantly increased risk of developing not only pre-cranioplasty but also post-cranioplasty hydrocephalus (p=0.008, p=0.010, respectively). In addition, the presence of pre-cranioplasty hydrocephalus was significantly associated with the development of post-cranioplasty hydrocephalus (p=0.001). The presence of pre- and post-cranioplasty hydrocephalus was significantly associated with a poor outcome (p=0.031, p=0.049, respectively). DC with a superior limit <25mm from the midline should be avoided to prevent the development of hydrocephalus.
    Journal of Clinical Neuroscience 12/2012; · 1.25 Impact Factor
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    ABSTRACT: OBJECTIVE: Primary brainstem hemorrhage (PBH) frequently causes severe disturbances of consciousness, papillary abnormalities, as well as respiratory and motor disturbances. The prognosis has been reported to be highly dependent on the clinical severity at presentation and the presence of certain radiological markers. However, the number of PBH patients enrolled in previous reports tended to be small, and precise statistical analyses were also lacking. The aim of this study was to analyze the impact of clinical or radiologic parameters on the outcome of patients with PBH. METHODS: We retrospectively reviewed 212 consecutive patients with PBH and analyzed the impact of the clinical or radiological parameters on the outcome of patients with PBH. RESULTS: Of the 212 patients, 134 (63.2%) were male and 78 (36.8%) were female, with an age range of 17-97 years (mean, 60.3 years). The median admission GCS score was 4. The outcomes included a good recovery in 13 patients (6.1%), moderate disability in 27 (12.7%), severe disability in 27 (12.7%), a vegetative state in 23 (10.8%), and death in 122 (57.5%). A multivariate analysis demonstrated bilateral hematoma extension, a GCS score ≤8, the presence of hydrocephalus, gender, and the hematoma volume to all be significantly associated with the 3-month mortality, while the GCS score ≤8, the presence of a pupillary abnormality, and the hematoma volume were found to be associated with the 3-month poor outcome. CONCLUSION: The identification of these factors is therefore considered to be useful for managing patients with PBH.
    Clinical neurology and neurosurgery 08/2012; · 1.30 Impact Factor
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    ABSTRACT: BACKGROUND: It is well known that intracranial lesions, which are already diagnosed on preoperative computed tomography, often expand after surgery, and the risk factors have been investigated. On the other hand, we have experienced cases in which new lesions, which were not detected on preoperative computed tomography, were found on postoperative computed tomography. However, little is known about the factors associated with such new postoperative lesions. Here, we investigated the predictive factors of new findings (NFs) on computed tomography early after surgery. METHODS: We conducted a retrospective registry-based review of 186 consecutive patients who underwent surgery for traumatic brain injury and investigated the prognostic factors of NFs on computed tomography early after surgery. RESULTS: Mean age was 51 years, and 67.2% were males among the 186 patients. NFs on postoperative computed tomography were observed in 29 patients (15.6%). A univariate analysis showed that Glasgow Coma Scale (GCS) score of 8 or less (p < 0.001), subdural hematoma as the primary indication for surgery (p = 0.012), midline shift (p < 0.001), absence of basal cistern (p < 0.001), and decompressive craniectomy and craniotomy as the surgical procedures (p < 0.001, p = 0.004, respectively) were significantly associated with NFs on postoperative computed tomography. A logistic regression analysis demonstrated that decompressive craniectomy as the surgical procedure (p = 0.001; odds ratio [OR], 8.1; 95% confidence interval [CI], 2.23-28.82), GCS score of 8 or less (p = 0.019; OR, 3.4; 95% CI, 1.23-9.52), and absence of basal cistern (p = 0.023; OR, 3.5; 95% CI, 1.19-10.35) were significant factors. CONCLUSION: Early postoperative computed tomography after surgery for head trauma seems to be warranted in patients presenting with the indicated predictive factors of NFs. LEVEL OF EVIDENCE: Prognostic/therapeutic study, level IV.
    The journal of trauma and acute care surgery. 08/2012;
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    ABSTRACT: OBJECTIVE: The aim of the present study was to investigate factors associated with the development of ventriculomegaly suggestive of hydrocephalus (VSOH) after decompressive craniectomy with hematoma evacuation for hemispheric hypertensive intracerebral hemorrhage. METHODS: This study focused on 21 patients who underwent decompressive craniectomy with hematoma evacuation for hemispheric hypertensive intracerebral hemorrhage. The patients' clinical and radiological findings were retrospectively reviewed. RESULTS: Eleven patients were male and ten were female, with an age range from 22 to 75 years (mean, 56.6 years). The preoperative Glasgow Coma Scale score ranged from 3 to 13 (mean, 6.9). Hematoma volumes ranged from 33.4 to 98.1ml (mean, 74.2ml). Hematoma locations were the basal ganglia in 10 patients and the subcortex in 11 patients. The presence of intraventricular hemorrhage was significantly associated with the development of VSOH (P=0.023). The distance of the decompressive defect to the midline and the presence of meningitis showed a strong trend for association with VSOH (P=0.051, P=0.090, respectively). CONCLUSION: Careful attention should be paid to the occurrence of VSOH after decompressive craniectomy with hematoma evacuation in intracerebral hemorrhage patients with intraventricular extension, meningitis, and/or a short distance of the decompressive defect to the midline.
    Clinical neurology and neurosurgery 06/2012; · 1.30 Impact Factor
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    ABSTRACT: OBJECTIVE: Intravenous tissue plasminogen activator (IV tPA) is an approved treatment for acute ischemic stroke. However, the effects of decompressive craniectomy (DC) after IV tPA administration for ischemic stroke are still largely unknown. The aim of this study was to investigate the safety and outcomes of DC after IV tPA administration. METHODS: We retrospectively reviewed patients who underwent DC for malignant hemispheric infarction. We compared 20 patients who underwent DC after IV tPA administration with another 20 patients who underwent DC without prior IV tPA administration. RESULTS: The patient characteristics did not differ between the DC patients with and without prior IV tPA administration. New intracranial bleeding or worsening of pre-existing ICH occurred in two patients (10%) in each group. Furthermore, the rates of an mRS score of 4-6, 5 or 6, and 6 did not differ significantly between the two groups. CONCLUSION: DC may be a safe and useful surgical procedure for space-occupying edema after IV tPA administration for acute stroke.
    Clinical neurology and neurosurgery 04/2012; · 1.30 Impact Factor
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    ABSTRACT: A 60-year-old man was admitted with slowly progressive dizziness. Cranial nerve evaluation found no abnormalities. Magnetic resonance imaging revealed a well-circumscribed mass with homogeneous enhancement located in the fourth ventricle. The patient underwent surgery for the removal of the tumor via the bilateral suboccipital approach. Subtotal removal of the tumor was achieved in a piecemeal fashion. Histological diagnosis was meningothelial meningioma. Fourth ventricular meningiomas are extremely rare. We reviewed the literature and discussed the features of fourth ventricular meningiomas.
    Acta neurologica Belgica 03/2012; 112(1):97-100. · 0.47 Impact Factor
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    ABSTRACT: Traumatic hematomas in the posterior fossa are rare, especially traumatic posterior fossa subdural hematomas (SDHs), which account for <1% of head injured patients. The aim of this study was to investigate the features of traumatic posterior fossa SDHs. We retrospectively reviewed clinical and radiologic findings, management, and outcomes of patients with traumatic posterior fossa SDH. Ten patients with traumatic posterior fossa SDHs were admitted to our hospital. There were seven males and three females, with an age range of 3 years to 97 years (mean, 57.5 years). Coagulopathies were observed in five patients. The causes of injury were motor vehicle crash in three patients, falls in six patients, and being hit by an iron plate in one patient. The mean admission Glasgow Coma Scale score was 8.3. Skull fractures were revealed in six patients. Hematoma sizes ranged from 5 mm to 20 mm (mean, 7.7 mm). Two patients presented with isolated posterior fossa SDHs, and eight patients presented with associated intracranial lesions. Only one patient was treated surgically for posterior fossa SDHs associated with intracerebellar hematomas. The poor outcome rate was 90% and the mortality was 50%. A review of the literature revealed the following characteristics of posterior fossa SDHs: (1) a relatively high frequency of occipital impacts and fractures, (2) a low Glasgow Coma Scale score, (3) a high frequency of associated intracranial lesions, especially supratentorial lesions and intracerebellar hematomas, (4) a potential for lesion evolution, especially within 2 days, and (5) a high poor outcome rate and mortality. IV.
    The journal of trauma and acute care surgery. 02/2012; 72(2):480-6.
  • Satoru Takeuchi, Yoshio Takasato, Hiroyuki Masaoka
    Internal Medicine 01/2012; 51(3):341-2. · 0.97 Impact Factor
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    ABSTRACT: In order to rapidly judge the response to intravenous tissue plasminogen activator (Ⅳ tPA) treatment, we retrospectively analyzed clinical data, such as MRI diffusion-weighted images (DWI), and treatment outcomes in 73 patients who developed anterior circulation disorders. The patients with favorable outcomes (modified Rankin Scale [mRS]: 2 or less) at discharge accounted for 32.9%. In these patients, the National Institutes of Health Stroke Scale (NIHSS) value, DWI Alberta Stroke Programme Early CT Score (ASPECTS), and the incidence of large artery (internal carotid artery [ICA]/sphenoidal segment of the middle cerebral artery [M1]) occlusion at their hospital visit were lower, higher, and lower, respectively (all P < 0.05 in univariate analysis). Multivariate analysis showed significant differences in DWI ASPECTS and the incidence of large artery occlusion. A DWI ASPECTS of at least 8 was found to be predictive of favorable outcomes. However, subclass analysis in the group with a DWI ASPECTS of 8 or higher predicting favorable outcome revealed 13 patients (41.9%) with unfavorable (mRS, 3-6) outcome. The factor associated with unfavorable outcomes is ICA occlusion. The combination of DWI ASPECTS and MRA appeared to be useful for predicting outcomes of Ⅳ tPA.
    Journal of medical and dental sciences 01/2012; 59(2):57-63.
  • Satoru Takeuchi, Yoshio Takasato, Hiroyuki Masaoka
    Internal Medicine 01/2012; 51(3):343. · 0.97 Impact Factor
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    ABSTRACT: This study aimed to investigate the clinicoradiological features in patients with traumatic peritentorial subdural hematomas (SDHs). We retrospectively reviewed the clinical and radiological findings, management criteria, and outcomes in 32 patients with peritentorial SDHs. The outcomes were classified as favorable (good recovery or moderate disability) or poor (severe disability, vegetative state, or death). Of the 32 patients, 19 were male and 13 were female. The patients' ages ranged from 10-92 years (mean age, 60.9 years). Coagulopathies were observed in 23 patients. Twenty-four patients presented with associated intracranial lesions. Eighteen patients had favorable outcomes and 14 had poor outcomes. All patients were treated conservatively. The presence of coagulopathy (p = 0.024) and presence of convexity SDH (p = 0.008) correlated with the outcome. The patients with traumatic peritentorial SDHs were predominantly male and relatively elderly, and had a high incidence of coagulopathy, associated intracranial lesions (especially falx SDHs), a high rate of impact in the occipital or frontal regions, and a low incidence of skull fractures. The factors that were correlated with outcome in patients receiving conservative therapy were the presence of coagulopathy and the presence of convexity SDH.
    Turkish neurosurgery 01/2012; 22(3):305-8. · 0.58 Impact Factor
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    ABSTRACT: We retrospectively reviewed the clinical and radiological findings, management, and factors correlated with outcomes in 20 patients with simultaneous multiple hypertensive intracranial hemorrhages (ICH). The mean admission Glasgow Coma Scale score was 7.8. The most common hematoma location was the putamen, while putamen-brainstem hematomas were the most common combination. The mean hematoma volume was 27.5 mL. Eight patients had favorable outcomes and 12 had poor outcomes. Statistical analysis identified that the GCS score on admission, hematoma distribution (unilateral supratentorial hematomas were the most favorable), and total hematoma volume were prognostic factors. This study provides important information on the clinicoradiological findings and prognosis in patients with simultaneous multiple hypertensive ICH.
    Journal of Clinical Neuroscience 09/2011; 18(9):1215-8. · 1.25 Impact Factor
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    ABSTRACT: We report on 17 patients with traumatic intra-cerebellar haematomas. We retrospectively reviewed patients' clinical and radiological findings, management criteria and outcomes. Ten patients had poor outcomes. Glasgow Coma Scale (GCS) score at admission was significantly higher in the favourable outcome group than in the poor outcome group (p = 0.010). The haematoma volume was significantly smaller in the favourable outcome group than in the poor outcome group (p = 0.025). There were also significant differences between the two groups in terms of types of haematoma location, the status of the brainstem cisterns, the status of the fourth ventricle, and the presence of associated subarachnoid haemorrhage (SAH) (p = 0.035, 0.002, 0.010, 0.003, respectively). The factors correlated with outcome were GCS score, the status of the brainstem cisterns and the fourth ventricle, the presence of associated SAH, haematoma volume and haematoma location. Further studies are needed to investigate the factors relevant to the management of traumatic intra-cerebellar haematomas.
    British Journal of Neurosurgery 02/2011; 25(1):62-7. · 0.86 Impact Factor
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    ABSTRACT: This report presents 12 consecutively managed patients with aneurysmal subarachnoid hemorrhage (SAH) associated with acute subdural hematoma (ASDH) who underwent decompressive craniectomy (DC) with special attention to their clinical characteristics and surgical outcomes. We retrospectively reviewed medical charts, radiologic findings, surgical notes, and video records. Among these 12 patients (mean age 59.1 years, 4 men, 8 women), the Hunt and Kosnik clinical grade was grade V in 7 patients (58.3%), grade IV in 2 patients (16.7%), grade III in 2 patients (16.7%), and grade II in 1 patient (8.3%). The aneurysms were located on the internal carotid artery in four patients, the middle cerebral artery in six patients, and the anterior communicating artery in two patients. Computed tomography findings on admission revealed ASDH in all patients. In addition, SAH was seen in 11 patients. An intracerebral hematoma was found in eight patients, intraventricular hemorrhaging occurred in four, and an acute hydrocephalus was seen in one patient. All patients underwent a microsurgical clipping procedure and an additional DC. Symptomatic vasospasm was confirmed in six (50%), and eight patients with chronic hydrocephalus received a ventriculoperitoneal shunt (67%). The Glasgow Outcome Scale at discharge showed good recovery in five patients (41.7%), severe disability in four (33.3%), vegetative state in two (16.7%), and death in one patient (8.3%). A favorable outcome was achieved in five patients (41.7%). We suggest that the DC was effective for reducing morbidity and mortality in poor grade patients with SAH presenting with ASDH.
    World Neurosurgery 01/2011; 75(1):73-7. · 1.77 Impact Factor
  • Satoru Takeuchi, Yoshio Takasato, Hiroyuki Masaoka
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    ABSTRACT: We report a rare case of chronic encapsulated intracerebral hematoma (CEIH) after radiosurgery for a cerebral arteriovenous malformation (AVM). A 49-year-old male underwent transarterial embolization and surgical excision of a cerebral AVM presenting with cerebral hemorrhage in the left temporal lobe. Stereotactic radiosurgery (SRS) was done after 12 months. Magnetic resonance imaging (MRI) 14 months after SRS showed a small-enhancing lesion close to the left lateral ventricle and marked white matter edema. At that time a diagnosis of radiation-induced necrosis was made and steroids administered. At 43 months after SRS, MRI showed a small-enhancing mass close to the lateral ventricle with a hematoma cavity. Surgical excision was performed and histological examination revealed that the capsule consisted of an outer collagenous layer and an inner granulated layer with deposits of hemosiderin, which was compatible with CEIH. CEIH should be considered after SRS for AVM.
    Neurology India 01/2011; 59(4):624-6. · 1.04 Impact Factor
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    ABSTRACT: The clinical and radiological findings, management, and outcomes in 35 patients with traumatic interhemispheric subdural haematoma (ISH) were reviewed retrospectively. Twenty-five patients had favourable outcomes and 10 had poor outcomes. All patients were treated conservatively for ISH. Univariate analysis found that the Glasgow Coma Scale (GCS) score (p < 0.001), hypovolemic shock (p = 0.018), skull fracture (p = 0.008), convexity or posterior fossa subdural haematoma (p = 0.008), and subarachnoid haemorrhage (SAH) were correlated with outcome (p < 0.001). Multivariate analysis showed that GCS score (p = 0.031; odds ratio [OR], 0.6; 95% confidence interval [CI], 0.3-0.9) and the presence of SAH (p = 0.023; OR, 14.2; 95% CI, 1.5-138.2) were significantly related to poor outcome. This study provides important information on the clinicoradiological findings and prognoses in patients with traumatic ISH.
    Journal of Clinical Neuroscience 12/2010; 17(12):1527-9. · 1.25 Impact Factor
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    Hiroyuki Masaoka
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    ABSTRACT: Cerebral blood flow (CBF) measurements during mild hypothermia therapy were made in 30 adult patients with severe head injuries (Glasgow Coma Scale score < or =18), by xenon enhanced computed tomography (Xe-CT). All patients but one underwent removal of hematomas and decompressive craniectomy. Immediately after surgery, hypothermia was induced by surface cooling, and a brain temperature of 32-35 degrees C was maintained for 3 days. During hypothermia therapy, CBF measurements by Xe-CT were made for all patients on post-injury days 1 to 4. From the arteriovenous-oxygen content difference and CBF values, the cerebral metabolic rate of oxygen (CMRO2) values were obtained. Outcome was assessed at discharge according to the patients' Glasgow Outcome Scale (GOS) scores. Patients were divided into two groups based on their outcomes. Nineteen patients (63%) showed good outcomes (GOS score of 4 or 5) and 11 (37%) showed poor outcomes (GOS score of 1, 2, or 3). Statistically significant differences were obtained for the mean global CBF and CMRO2 values between the good and poor outcome groups. In this study, we demonstrated that CBF measurement may be useful to predict neurological outcomes following severe traumatic brain injury in patients undergoing hypothermia as well as to identify those who might not likely benefit from hypothermia therapy.
    Journal of medical and dental sciences 06/2010; 57(2):133-8.
  • Journal of Anesthesia 04/2010; 24(2):315-6. · 0.87 Impact Factor
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    ABSTRACT: Hypereosinophilic syndrome (HES) is a rare disorder that can cause ischemic stroke. We present a patient with middle cerebral artery (MCA) occlusion resulting from HES. Transarterial thrombolysis resulted in MCA recanalization and adjuvant therapy may have contributed to stabilization of the underlying HES in our patient.
    Journal of Clinical Neuroscience 03/2010; 17(3):377-8. · 1.25 Impact Factor
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    ABSTRACT: Decompressive craniectomy for traumatic brain injury patients has been shown to reduce intracranial hypertension, while it often results in increased brain edema and/or contralateral space-occupied hematoma. The purpose of this study was to determine the prognosis of bilateral decompressive craniectomy in severe head injury patients with the development of either bilateral or contralateral lesions after ipsilateral decompressive craniectomy. Twelve patients underwent bilateral decompressive craniectomy among 217 individuals who had been treated with decompressive craniectomy with dural expansion from September 1995 to August 2006. The following patient data were retrospectively collected: age, neurological status at admission, time between injury and surgical decompression, time between first and second decompression, laboratory and physiological data collected in the intensive care unit, and outcome according to the Glasgow Outcome Scale. Patient outcomes fell into the following categories: good recovery (three patients); mild disability (one patient); severe disability (two patients); persistent vegetative state (one patient); and death (five patients). Patients with good outcomes were younger and had better pupil reactions and neurological statuses on admission. Other factors existing prior to the operation did not directly correlate with outcome. At 24 h post-surgery, the average intercranial pressure (ICP), cerebral perfusion pressure (CPP), glucose level, and lactate level in patients with poor outcomes differed significantly from those of patients with a good prognosis. Head injury patients with either bilateral or contralateral lesions have poor prognosis. However, bilateral decompressive craniectomy may be a favorable treatment in certain younger patients with reactive pupils, whose ICP and CPP values are stabilized 24 h post-surgery.
    Acta neurochirurgica. Supplement 01/2010; 106:265-70.

Publication Stats

541 Citations
101.29 Total Impact Points

Institutions

  • 2011
    • National Defense Medical College
      • Department of Neurosurgery
      Tokorozawa, Saitama-ken, Japan
  • 2001–2011
    • NHO Disaster Medical Center
      Nagasaki, Nagasaki, Japan
  • 2008–2010
    • NHO Nagasaki Medical Center
      • Department of Neurosurgery
      Nagasaki, Nagasaki, Japan
  • 1989–2010
    • Tokyo Medical and Dental University
      • Department of Neurosurgery
      Edo, Tōkyō, Japan
  • 1985
    • National Institutes of Health
      Maryland, United States