Tetsuyoshi Horiuchi

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.

Surgical treatment for aneurysmal subarachnoid hemorrhage in the 8TH and 9TH decades of life

OBJECTIVE:Industrialized countries are facing a rapid increase of their senior populations. Consequently, the number of elderly patients with aneurysmal subarachnoid hemorrhage is increasing. The purpose of this study was to assess the results of surgical repair for ruptured aneurysm in elderly patients. METHODS:We retrospectively investigated elderly patients (ages 70–89 yr) who were undergoing surgical treatment for ruptured aneurysm during the 15-year period 1988 to 2002 and compared patients in the 8th and 9th decades of life. Generally, patients were treated surgically within 72 hours after ictus. RESULTS:Of the total of 2835 patients, there were 509 patients (18.0% of total patients) in the 8th decade and 99 patients (3.5%) in the 9th decade of life. Because data were incomplete and patients who received ventricular drainage or ventriculoperitoneal shunt without aneurysmal repair were excluded, 449 and 89 patients in the 8th and 9th decades of life, respectively, were analyzed. No differences in sex, preoperative grade, preoperative computed tomographic findings, location of aneurysm, and aneurysm size were observed between the two decades. Preoperative grade and computed tomographic findings were predictors of favorable outcomes in the 8th and 9th decades. Patient age was a significant predictor of outcome in the 8th but not in the 9th decade. CONCLUSION:To the best of our knowledge, this study is the largest series of its kind to date. Advanced age alone does not exclude adequate surgical repair in patients with aneurysmal rupture in the 9th decade of life.

Fenestrated oculomotor nerve caused by internal carotid-posterior communicating artery aneurysm: case report.

OBJECTIVE AND IMPORTANCE The fenestrated oculomotor nerve associated with the internal carotid-posterior communicating artery aneurysm is very rare. CLINICAL PRESENTATION A 48-year-old woman had a history of subarachnoid hemorrhage caused by a ruptured right middle cerebral artery aneurysm, which was wrapped with good postoperative course. Twenty years later, the patient suffered frontal headache with a mild oculomotor nerve paresis in the right side. Follow-up neuroimaging studies demonstrated a de novo right internal carotid-posterior communicating artery aneurysm. INTERVENTION The aneurysm was exposed and clipped via a right pterional route. The fenestrated oculomotor nerve associated with the aneurysm was confirmed at surgery. CONCLUSION We speculated that the fenestration was most likely caused, by the growth of the aneurysm.

Safe and minimally invasive laminoplastic laminotomy using an ultrasonic bone curette for spinal surgery: technical note

BACKGROUND Ultrasonic surgical aspirators have been used mainly for removing brain tumors. Because of their longitudinal and torsional tip, they are used for cutting the bone structures in spinal surgery installing a scalpel-type tip. The purpose of this report is to describe the effectiveness and surgical pitfalls of an ultrasonic bone curette in laminoplastic laminotomy and hemilaminotomy. METHODS We present 12 patients who underwent laminoplastic laminotomy and hemilaminotomy. We used a SONOPET UST-2001 ultrasonic bone curette with HB-05S handpieces (M and M Co, Ltd, Tokyo, Japan). After a tumor was removed, titanium plates were used for the laminoplastic laminotomy and hemilaminotomy. The technical advantage of an ultrasonic bone curette and procedure-related complication were examined. RESULTS There were no major procedure-related complications such as cord injury. Wound infection and subcutaneous fluid collection caused by cerebrospinal fluid leakage did not occur for reconstruction of posterior bony structure. In 1 patient with calcified dura mater associated with tumor, dural tear occurred. The width of the tip was narrow enough for resected laminae to be fused postoperatively, and spinal instability did not occur in all cases. CONCLUSION The scalpel-type ultrasonic bone curette is useful for cutting bone and effective for reconstruction of the laminae. Laminotomy with an ultrasonic bone curette is safe and minimally invasive. To prevent dural tear, we recommend drilling laminae to make the bone thin as the first step, followed by cutting the remaining laminae using a bone curette especially in cases with calcified or tense dura mater.

Desmoplastic fibroma of the calvarium

A very rare case of desmoplastic fibroma located in the frontal bone is presented. It was discovered in a 29-year-old female who complained of a painful swelling in the right frontal region. The tumour was resected en bloc and there has been no recurrence. Findings on magnetic resonance imaging, angiography and radionuclide bone scans of the tumour are reported. The clinical, neuroradiological and histopathological features are discussed.

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.

Emergency revascularization for acute main-trunk occlusion in the anterior circulation

We report the surgical results in patients with acute cerebral main-trunk occlusion in the anterior circulation. Between April 2004 and March 2005, 26 patients were surgically treated within 24h after the onset. The occlusion occurred in the internal carotid artery in 10 patients, in the middle cerebral artery in 15, and in the anterior cerebral artery in 1. We investigated the clinical characteristics and surgical treatment and evaluated the outcome using the modified Rankin Scale (mRS). Nine patients underwent anastomosis, 14 had an embolectomy, and 3 had a carotid endarterectomy. In all the patients, revascularization was achieved, and neurological improvement was obtained. At 6months after the onset, eight (30.8%) patients showed a good recovery (defined as grade 1 on the mRS), seven (26.9%) were rated as grade 2, eight (30.8%) were grade 3, and three (11.5%) were grade 4. Manual muscle test on admission was significantly different between the good outcome and the poor outcome groups at 6months after onset. None of the patients experienced any complications related to the surgery. Early surgical revascularization can be an effective and safe treatment modality in appropriately selected patients with acute cerebral main-trunk occlusion in the anterior circulation.

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.

Thoracic dumbbell intra- and extramedullary schwannoma

We present a rare case of a solitary dumbbell intra- and extramedullary schwannoma of the thoracic spine in a 54-year-old man without signs of von Recklinghausens disease. The patient presented with motor weakness in the left lower extremity, bilateral sensory impairment below the T9 dermatome and rectovesical dysfunction. Preoperative magnetic resonance imaging was suspicious for an intradural extramedullary tumor. At operation, the tumor was located posteriorly, at the midline, with no relationship to the posterior nerve roots and was firm and adherent to the adjacent spinal cord, which surrounded the intramedullary portion of the tumor. The intramedullary mass was completely removed with sharp dissection after removal of the extramedullary mass. Surgery resulted in minimal postoperative neurological deficits. These tumors may arise from the Schwann cells of the nerve plexus surrounding vessels in the posterior median sulcus and thus may grow in both an intra- and extramedullary fashion. The optimal treatment of these schwannomas is total removal.