Yoshikazu Kusano

Description and first clinical application of AirWay Scope for tracheal intubation.

We have developed a novel airway apparatus, AirWay Scope, which we have used in the orotracheal intubation of 10 consecutive patients requiring general anesthesia before neurosurgical procedures. The characteristic shape of the introducer (INTLOCK), the tube guiding function and the sighting device of the AirWay Scope has possibility to facilitate tracheal intubation. Here, we report the first clinical application of this system and describe potential advantages of the apparatus.

Characteristics of Distal Posteroinferior Cerebellar Artery Aneurysms

OBJECTIVEDistal posteroinferior cerebellar artery (PICA) aneurysms are rare and have not been well investigated previously. We report our series of 24 patients with 27 distal PICA aneurysms. METHODSAll patients with distal PICA aneurysms that were surgically treated at Shinshu University Hospital and its affiliated hospitals between 1983 and 2001 were reviewed retrospectively. Data relating to clinical, radiological, and intraoperative findings were analyzed. RESULTSIn our series, distal PICA aneurysms reached an incidence of 0.28 and 0.38% of all intracranial aneurysms and ruptured aneurysms, respectively. There were 23 ruptured and 4 unruptured distal PICA aneurysms. Of these, 74.1% were saccular, 7.4% fusiform, and 18.5% dissecting aneurysms. Primarily the telovelotonsillar segment of the PICA was affected. Usually, the surgical outcome was favorable and was influenced by the obstructive hydrocephalus and the preoperative grade. It was sometimes difficult to detect the ruptured distal PICA aneurysm on the initial angiogram, and an extracranial origin of the PICA was sometimes observed. CONCLUSIONThis review summarizes the presentation and outcome of a large series of 24 patients with 27 distal PICA aneurysms, and we conclude that distal PICA aneurysms are benign entities compared with vertebral artery-PICA aneurysms. Characteristics that should be considered in the treatment of distal PICA aneurysms are discussed.

Prediction of Functional Outcome in Acute Cerebral Hemorrhage Using Diffusion Tensor Imaging at 3T: A Prospective Study

BACKGROUND AND PURPOSE: Early evaluation of the pyramidal tract is a prerequisite in patients with intracerebral hemorrhage (ICH) in order to decide the optimal treatment or to assess appropriate rehabilitation. The aim of this study was to evaluate and predict the neuromotor and functional outcome of an ICH by using diffusion tensor imaging (DTI) in the acute phase. MATERIALS AND METHODS: Eighteen patients with a hemiparetic supratentorial ICH were prospectively studied with DTI within 2 days after onset. A region-of-interest-based analysis was performed for the fractional anisotropy (FA) of the pyramidal tract in the cerebral peduncles. The degree of paresis was assessed at day 0 and day 28 by paresis grading (PG). The functional outcome was evaluated by the modified Rankin Scale (mRS). RESULTS: The FA in the affected side was significantly lower compared with that of the unaffected side (P = .001) with the mean diffusivity remaining unchanged (P = .50). The ratio of the FA (rFA) in the affected side to the unaffected side was significantly correlated with the PG at day 0 and 28 and the mRS score at day 28 (P = .002, r = −0.674; P < .001, r = −0.767; and P = .002, r = −0.676). The rFA for the good and poor outcomes based on the PG was significantly different (P < .001). The cutoff point of the rFA for the good and poor outcomes was set at 0.85 (sensitivity, 100%, specificity, 100%). CONCLUSIONS: We conclude that DTI can evaluate the motor deficit quantitatively and may predict the functional outcome in patients with an ICH who were scanned within 2 days after the ICH onset.

Loss of visual evoked potential following temporary occlusion of the superior hypophyseal artery during aneurysm clip placement surgery : Case report

The authors report a case in which a 62-year-old woman with a history of subarachnoid hemorrhage due to a ruptured aneurysm was found to have a de novo paraclinoid aneurysm in the right internal carotid artery during a routine medical examination. Surgical clip placement was performed via a contralateral pterional approach under visual evoked potential (VEP) monitoring. The superior hypophyseal artery (SHA) was found to originate from the aneurysm body. The artery was temporarily occluded prior to application of the clip to the aneurysm neck. The VEP signal was lost 3 minutes after the SHA was occluded, and the potentials gradually recovered 10 minutes after the artery was released. The disappearance of VEP signal was reproducible with SHA occlusion. The clip was applied to the aneurysm body to preserve the origin of the SHA. The patient did not have any deterioration of vision after surgery. Intraoperative VEP monitoring can be used to help determine whether the SHA can be sacrificed safely.

Relationship between the ophthalmic artery and the dural ring of the internal carotid artery: Clinical article

OBJECT The ophthalmic artery (OphA) usually arises from the intradural internal carotid artery (ICA), and the extradural origin has also been known. However, the interdural origin is extremely rare. The purpose of this paper was to clarify the origin of the OphA in patients with a paraclinoid aneurysm in the ICA based on intraoperative findings. METHODS The authors retrospectively examined 156 patients who underwent direct surgical treatment for 166 paraclinoid aneurysms during a 17-year period. Based on intraoperative findings, 119 ophthalmic arteries were analyzed with respect to their origins. RESULTS The OphA originated from the intradural ICA on 102 sides (85.7%), extradural on 9 (7.6%), and interdural on 8 (6.7%). Although the extradural origin might be recognized preoperatively, it was difficult to distinguish the interdural origin of the OphA from the intradural one. CONCLUSIONS The incidence of the interdural origin was 6.7% and was not as rare as the authors expected. Neurosurgeons should know the possible existence of the interdural origin of the OphA to section the medial side of the dural ring.

De novo aneurysm: case reports and literature review.

BACKGROUND AND IMPORTANCE:Formation of cerebral de novo aneurysms (CDNAs) is rare, and the pathogenesis remains obscure. We analyzed factors involved in formation of CDNAs and suggest guidelines for follow-up of patients. CLINICAL PRESENTATION:We retrospectively reviewed intracranial aneurysms at our institute and published reports from 1964 to 2008. Eleven patients were found with CDNAs, and 138 patients were collected from the published literature. We assessed the clinical characteristics, such as sex, size, and site of CDNA, past history, and time to occurrence of CDNAs. Of 11 patients, 10 were female and 1 was male; the mean age of the first onset was 53 years (range, 25-69 years). The mean time between first aneurysms and CDNAs was 10.6 years (range, 3-29 years). The most common site of occurrence was anterior circulation. One patient experienced contralateral occurrence, and 2 patients changed from anterior to posterior circulation CDNAs. Six (54.5%) patients had a history of arterial hypertension. Results from analysis of the whole series from the literature revealed that the risk of rupture increased with a previous history of hemorrhage. Contralateral occurrence of CDNAs was related to previous location, and multiplicity, whereas the occurrence of anterior to posterior changes of CDNAs and shorter interval only correlated with an older age group. CONCLUSION:Although the formation of CDNAs is rare, several factors may contribute to its occurrence. Female patients with a history of arterial hypertension were at a higher risk for CDNA occurrence. We recommend follow-up imaging studies within 10 years after the initial aneurysms; therefore, at least 50% of CDNAs can be found before rupture.

Ruptured anterior paraclinoid aneurysms

The purpose of this study was to evaluate cases of subarachnoid hemorrhage (SAH) from ruptured anterior (dorsal) paraclinoid aneurysms. Anterior paraclinoid aneurysms are defined as aneurysms arising from the anterolateral wall of the proximal internal carotid artery without any relationship to an arterial branch. Between 1991 and 2008, a total of 159 patients with 169 paraclinoid aneurysms were treated at the Shinshu University Hospital and its affiliated hospitals. A retrospective analysis was carried out using charts, operation records, operation videos, and neuroimagings. Twenty six patients had anterior paraclinoid aneurysm. Six patients presented with SAH. Three aneurysms were saccular and the others were blister-like aneurysms based on operative findings. Neck laceration or premature rupture frequently happened during the clipping surgery even though the aneurysm was saccular type. The treatment of a ruptured anterior paraclinoid aneurysm is quite difficult. Trapping and bypass would be recommended for such fragile aneurysms.

Ectopic pituitary adenoma associated with an empty sella: a case report and review of the literature.

A case of ectopic pituitary adenoma in the sphenoid sinus associated with an empty sella is reported. The coexistence of an ectopic pituitary adenoma and an empty sella is quite rare. The diagnosis was made with an intraoperative finding of the intact dura mater of the sellar floor. In the present case, the hypointense line that coated the pituitary gland was clearly demonstrated on 3‐tesla T2‐weighted magnetic resonance imaging. The hypointense line is considered to be the pituitary capsule and was critical in diagnosing this rare entity.

Local brain herniation after partial membranectomy for organized chronic subdural hematoma in an adult patient: Case report and review of the literature

Objective: Local brain herniation after removal of chronic subdural haematoma is extremely rare, especially in adult patients. This study reports a case of local brain herniation after partial membranectomy for organized chronic subdural haematoma. Case report: A 77-year-old man presented with dysarthria and dysphasia caused by local brain herniation of the right frontal lobe through a defect of the inner membrane. The herniated brain was detected by magnetic resonance (MR) imaging. The patient underwent a craniotomy to release the herniated and strangulated brain, which were consistent with the MR imaging findings. The patient recovered fully within 1 month after surgery. Conclusions: To date, five cases of brain herniation through the internal subdural membrane have been reported as complications of chronic subdural haematomas. All but one case occurred in the paediatric population. Urgent surgery should be performed, even if an adult patient suffers from local brain herniation, for preservation of brain function. This is the sixth reported case of brain herniation through a defect of the inner membrane and the second reported case in the adult population.

Subtemporal transtentorial approach for recurrent trigeminal neuralgia after microvascular decompression via the lateral suboccipital approach: case report.

Microvascular decompression (MVD) via lateral suboccipital craniotomy is the standard surgical intervention for trigeminal neuralgia (TN). For recurrent TN, difficulties are sometimes encountered when performing reoperation via the same approach because of adhesions and prosthetic materials used in the previous surgery. In the present case report the authors describe the efficacy of the subtemporal transtentorial approach for use in recurrent TN after MVD via the lateral suboccipital approach. An 86-year-old woman, in whom an MVD via a lateral suboccipital craniotomy had previously been performed for TN, underwent surgery for recurrent TN via the subtemporal transtentorial approach, which provided excellent visualization of the neurovascular relationships and the trigeminal nerve without adhesions due to the previous surgery. Her TN disappeared after the MVD. The present approach is ideal for visualizing the trigeminal root entry zone, and the neurovascular complex can be easily dissected using a new surgical trajectory. This approach could be another surgical option for reoperation when the previous MVD had been performed via the suboccipital approach.