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Yamakami I.,Chiba Central Medical Center | Ito S.,Neurosurgery | Higuchi Y.,Chiba University
Journal of Neurosurgery | Year: 2014

Object. Management of small acoustic neuromas (ANs) consists of 3 options: observation with imaging followup, radiosurgery, and/or tumor removal. The authors report the long-term outcomes and preservation of function after retrosigmoid tumor removal in 44 patients and clarify the management paradigm for small ANs. Methods. A total of 44 consecutively enrolled patients with small ANs and preserved hearing underwent retrosigmoid tumor removal in an attempt to preserve hearing and facial function by use of intraoperative auditory monitoring of auditory brainstem responses (ABRs) and cochlear nerve compound action potentials (CNAPs). All patients were younger than 70 years of age, had a small AN (purely intracanalicular/cerebellopontine angle tumor ≤ 15 mm), and had serviceable hearing preoperatively. According to the guidelines of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery Foundation, preoperative hearing levels of the 44 patients were as follows: Class A, 19 patients; Class B, 17; and Class C, 8. The surgical technique for curative tumor removal with preservation of hearing and facial function included sharp dissection and debulking of the tumor, reconstruction of the internal auditory canal, and wide removal of internal auditory canal dura. Results. For all patients, tumors were totally removed without incidence of facial palsy, death, or other complications. Total tumor removal was confirmed by the first postoperative Gd-enhanced MRI performed 12 months after surgery. Postoperative hearing levels were Class A, 5 patients; Class B, 21; Class C, 11; and Class D, 7. Postoperatively, serviceable (Class A, B, or C) and useful (Class A or B) levels of hearing were preserved for 84% and 72% of patients, respectively. Better preoperative hearing resulted in higher rates of postoperative hearing preservation (p = 0.01); preservation rates were 95% among patients with preoperative Class A hearing, 88% among Class B, and 50% among Class C. Reliable monitoring was more frequently provided by CNAPs than by ABRs (66% vs 32%, p < 0.01), and consistently reliable auditory monitoring was significantly associated with better rates of preservation of useful hearing. Long-term follow-up by MRI with Gd administration (81 ± 43 months [range 5-181 months]; median 7 years) showed no tumor recurrence, and although the preserved hearing declined minimally over the long-term postoperative follow-up period (from 39 ± 15 dB to 45 ± 11 dB in 5.1 ± 3.1 years), 80% of useful hearing and 100% of serviceable hearing remained at the same level. Conclusions. As a result of a surgical technique that involved sharp dissection and internal auditory canal reconstruction with intraoperative auditory monitoring, retrosigmoid removal of small ANs can lead to successful curative tumor removal without long-term recurrence and with excellent functional outcome. Thus, the authors suggest that tumor removal should be the first-line management strategy for younger patients with small ANs and preserved hearing. ©AANS, 2014. Source


Wada M.,Chiba Rehabilitation Center | Iizuka M.,Chiba Rehabilitation Center | Iwadate Y.,Chiba University | Yamakami I.,Chiba Central Medical Center | And 2 more authors.
Thrombosis Research | Year: 2013

Introduction The diagnosis and treatment of deep vein thrombosis/pulmonary embolism (DVT/PE) are important issues not only in acute-care hospitals, but also in rehabilitation hospitals. To test the hypothesis that DVT/PE occurring at rehabilitation hospitals is carried over from acute-care hospitals, we evaluated a method of DVT screening on admission that combined D-dimer (D-D) measurement and compression ultrasound (CUS). Material and Methods This prospective single-center observational study included 1043 patients who were admitted to our rehabilitation hospital between August 1, 2007, and August 1, 2011, after excluding those meeting the exclusion criteria. We screened patients on admission and observed the occurrence of DVT/PE until discharge. Results Of the 1043 patients, 152 (14.6%) had a D-D level of ≥ 3.0 μg/mL on admission. CUS was performed for these patients and indicated the presence of DVT in 15 patients (1.4%), who were subsequently treated. Of these 15 patients, six (40%) had no DVT symptoms, and five of these six patients had spinal cord injury. Of 137 patients who were CUS negative, two developed DVT/PE within 8 days of hospitalization, and recovery was achieved by treatment. No subsequent occurrence was observed. Conclusions These results indicated all cases were carried over from acute-care hospitals. Six out of 15 patients had no symptoms of DVT/PE. Thus, this method of DVT screening on admission to a rehabilitation hospital is useful for risk management. © 2013 Elsevier Ltd. Source


Terada H.,Chiba University | Terada H.,Chiba Central Medical Center | Kurayama T.,Chiba University | Nakazawa K.,Chiba University | And 2 more authors.
Neuroscience Letters | Year: 2015

Transcranial direct current stimulation (tDCS) has been reported to modify cortical function by inducing alterations in the underlying brain function. P50auditory evoked potentials, as assessed using a paired auditory stimulus (S1 and S2) paradigm, are thought to reflect a sensory gating process in which the functional involvement of the dorsolateral prefrontal cortex (DLPFC) is suggested. P50 sensory gating has also been reported to be associated with the pathogenesis of psychiatric diseases such as schizophrenia and anxiety-related disorders. Here we investigated whether the tDCS over the DLPFC could modulate the cortical function leading to alteration of the P50 sensory gating. P50 gating indices (the S2/S1 ratio and S1-S2 difference) were measured during the tDCS (current 1.0. mA, duration 15. min) over the DLPFC with different conditions (anodal, cathodal and sham). Ten male healthy volunteers were studied on separate days in a single blinded paradigm. We observed that the cathodaltDCS significantly altered the mean P50 gating indices compared to the other two conditions. Our results suggest that sensory gating could be modulated by cathodaltDCS on the left DLPFC but not by anodal/sham tDCS. © 2015 Published by Elsevier Ireland Ltd. Source


Yamakami I.,Chiba Central Medical Center | Higuchi Y.,Chiba University | Horiguchi K.,Chiba University | Saeki N.,Chiba University
Neurosurgical Review | Year: 2011

Aggressive tumor removal is not always the best treatment for petroclival meningioma (PCM). However, radical removal actually provides the cure with minimal morbidity. We evaluated the relation of surgical results and tumor size in the PCM removal to clarify the treatment policy for PCM. This study comprised 32 consecutive patients with newly-diagnosed PCM who underwent tumor removal; tumor size was small (< 3 cm) in 12 patients and large (3 cm) in 20. Tumor removal was classified into radical (Simpson's grade I/II) and non-radical (Simpson's grade III/IV). Removal of small PCM was 11 radical and one non-radical; no surgical morbidity/mortality occurred and postoperative regular follow-up using magnetic resonance imaging showed no recurrence in the period of 66 ± 45 months. Removal of large PCM was eight radical and 12 non-radical; despite no mortality, the incidence of permanent cranial nerve deficits and major neurological deficits newly developed postoperatively was 35% and 25%, respectively. Radical removal was significantly more frequent in small PCMs than in large PCMs. Permanent cranial nerve deficits newly developed postoperatively and poor outcome (Karnofsky score 80) were significantly more frequent in large PCMs than in small PCMs. Radical removal of small PCM is achieved with minimal morbidity and results in the cure. Notwithstanding high morbidity, aggressive removal of large PCM does not achieve a high rate of radical removal. To find and remove PCM radically while it is small is the only way to cure the disease with minimal morbidity. © 2011 Springer-Verlag. Source


Wada M.,Chiba Rehabilitation Center | Yamakami I.,Chiba Central Medical Center | Higuchi Y.,Chiba University | Tanaka M.,Sanmu Medical Center | And 3 more authors.
Clinical Neurology and Neurosurgery | Year: 2014

Objective The present study tested the hypothesis of whether antiplatelet agents (APA) induce chronic subdural hematoma (CSDH) recurrence via a platelet aggregation inhibitory effect. Method We examined risk factors for CSDH recurrence, focusing on APA, in 719 consecutive patients who admitted to three tertiary hospitals and underwent burr-hole craniostomy and irrigation for CSDH. This was a multicenter, retrospective, observational study. Results Age, sex, history of diabetes mellitus, hypertension, chronic renal failure, alcohol consumption habits, consciousness disturbance on admission, or preoperative CT density was not associated with recurrence. Subdural drainage was significantly associated with less recurrence. Preoperative oral APA administration was significantly associated with more recurrence. The recurrence rate of CSDH in non-APA group was 11% if surgery was performed on admission. However, if surgery was performed immediately after discontinuation of oral APA administration, the recurrence rate in APA group significantly increased to 32% (p value < 0.0001; odds ratio, 3.77; 95% confidence interval, 1.72-8.28). The effect of APA on CSDH recurrence gradually diminished as the number of days until initial surgery, after stopping APA, increased. Conclusion Antiplatelet therapy significantly influences the recurrence of CSDH. © 2014 Elsevier B.V. Source

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