Endoscopic endonasal transsphenoidal surgery in acromegaly with conchal sphenoid sinus.

BACKGROUND: A conchal non-pneumatized sphenoid sinus tends to be considered as unfavorable for transsphenoidal surgery because of procedural difficulties. Especially in acromegalic patients, the proportion of the conchal type of sphenoid sinus is potentially high compared with that of other patients who have a pituitary tumor. This report investigates the characteristics and surgery of the conchal type of sphenoid sinus in acromegaly along with the internal bone properties. CLINICAL PRESENTATION: A 70-year-old man with acromegaly underwent endoscopic endonasal transsphenoidal surgery. Intraoperatively, the anterior wall of the non-pneumatized sphenoid was cortical, however, the cancellous bone was very soft, included fatty tissue, and was easily removed by suction. The sellar lesion could be reached without any problems, and finally, total tumor resection was achieved. CONCLUSION: Based on this surgical case, the conchal sphenoid sinus of acromegaly is not always homogeneous solid bone but may contain soft fatty tissue. Therefore, although the sphenoidal characteristics may have an impact on the surgical procedures, precise assessment pre- and intraoperatively can make transsphenoidal surgery with conchal sphenoid sinus feasible.

Neurocysticercosis in Japan.

Neurocysticercosis is a condition rarely reported in Japan, and therefore, the specific route of infestation in our set up has not been conclusively elucidated. Preoperative diagnosis remains difficult to make with certainty due to the slowly evolving nature of the disease and the fact that there are no typical characteristic clinical findings particularly associated with the disease. The hematological, serological, serum biochemistry, stool, and radiological tests were nonspecific for neurocysticercosis. The characteristic neuro-imaging findings were demonstrated in this case, and histopathology confirmed Taenia solium parenchymal infestation.

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.

A case of presumably Rathke's cleft cyst associated with postoperative cerebrospinal fluid leakage through persisting embryonal infundibular recess.

Persisting embryonal infundibular recess (PEIR) is a rare anomaly of the third ventricular floor. Only eight cases have been published. In this report, a case of presumably Rathke's cleft cyst associated with cerebrospinal fluid leakage caused by PEIR is described. An 81-year-old woman underwent endoscopic transsphenoidal surgery for the intra- and supra-sellar cystic lesion. Intraoperatively a hole was confirmed over the sella turcica connecting the sellar cyst and the infundibular recess. Liquorrhea did not occur throughout the procedure. A computed tomography (CT) scan obtained immediately after surgery disclosed accumulation of air in the third and lateral ventricles, in addition to the intra- and supra-sellar region. Air accumulation resolved spontaneously after bed rest for 11 days and she was discharged without neurological deficits. However, she required the second transsphenoidal surgery to repair the sellar floor because of bacterial meningitis caused by liquorrhea on the postoperative day 23. A postoperative 3-tesla magnetic resonance image revealed a deep infundibular recess connecting the sella turcica and the third ventricle, which was considered to be PEIR. To the best our knowledge, this is the first reported case describing the intraoperative findings of PEIR.

Early changes in tissue perfusion after tissue plasminogen activator administration in hyperacute ischemic stroke: initial experiences with arterial spin labeling perfusion magnetic resonance imaging.

Cerebral perfusion monitoring is an important component of hyperacute stroke treatment. Arterial spin labeling (ASL) perfusion magnetic resonance (MR) imaging provides a noninvasive method of cerebral perfusion observation. Rapid changes in cerebral perfusion were demonstrated in two patients admitted one hour after onset of hyperacute stroke who underwent recombinant tissue plasminogen activator (rt-PA) treatment. Serial MR images and ASL images were taken on admission and after rt-PA administration. Cerebral blood flow (CBF) values were obtained using the CBF workstation and analysis software. Interpretable ASL images were taken in both patients. Perfusion deficits were consistent with symptoms and/or MR angiography imaging abnormalities. Delayed arterial transit effect was present in one patient; serial imaging showed improvement of CBF after rt-PA treatment in both patients. ASL perfusion MR imaging can provide rapid noninvasive multislice imaging in hyperacute ischemic stroke, and can depict early perfusion deficit and quantify regional CBF concomitantly.

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.

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.

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.

Role of adenosine A2 receptors in regulation of cerebral blood flow during induced hypotension.

The mechanisms responsible for vascular autoregulation in the brain during changes in mean arterial blood pressure are ambiguous. Potentially, adenosine, a purine nucleoside and potent vasodilator, may be involved as earlier studies have documented an increase in brain adenosine concentrations with cerebral ischemia and hypotension. Consequently, we tested the hypothesis that adenosine is involved in vasodilatation during hypotension within the autoregulatory range (>50 mm Hg) by exposing adenosine 2a receptor (A2aR) knockout and wild type (WT) mice to short (2 to 5 mins) periods of hypotension. We found that autoregulation was significantly (P<0.05) impaired by 29% in A2a knockout mice as compared with WT animals. Furthermore, the A2R antagonist (A2a>A2b:10-85>1), ZM-241385, in a dose (1, 5, 10 mg/kg, intraperitoneally)-related manner, attenuated autoregulation in WT mice. In knockout mice treated with ZM-2413585 (5 and 10 mg/kg), autoregulation was further impaired indicating that A2b receptors also participated in cerebral vasodilatation. Treatment with dipyridamole (1.0 mg/kg) that increases extracellular concentrations of adenosine improved autoregulation in the A2aR knockout mice. We would conclude that adenosine through both A2a and A2b receptors is involved in physiologic vascular regulation during hypotension even within the autoregulatory range.

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.

Regulation of cerebral vasculature in normal and ischemic brain.

We outline the mechanisms currently thought to be responsible for controlling cerebral blood flow (CBF) in the physiologic state and during ischemia, focusing on the arterial pial and penetrating microcirculation. Initially, we categorize the cerebral circulation and then review the vascular anatomy. We draw attention to a number of unique features of the cerebral vasculature, which are relevant to the microcirculatory response during ischemia: arterial histology, species differences, collateral flow, the venous drainage, the blood-brain barrier, astrocytes and vascular nerves. The physiology of the arterial microcirculation is then assessed. Lastly, we review the changes during ischemia which impact on the microcirculation. Further understanding of the normal cerebrovascular anatomy and physiology as well as the pathophysiology of ischemia will allow the rational development of a pharmacologic therapy for human stroke and brain injury.

Cerebral blood flow response in adenosine 2a receptor knockout mice during transient hypoxic hypoxia.

We evaluated cerebral blood flow by laser Doppler during 30 secs of hypoxia (0.10 FiO(2)) in anesthetized, ventilated adenosine 2a receptor knockout (A2aR KO) and wild-type (WT) mice to test the hypothesis that cerebral hypoxic hyperemia in KO mice would be attenuated. We also studied the effects of selective and nonselective A2aR antagonists. During 30 secs of hypoxia, P(a)O(2) decreased significantly (P<0.05) and to a similar degree in both types of mice, whereas P(a)CO(2) remained relatively stable. However, mean arterial blood pressure (MABP) decreased to a greater extent (P<0.05) during hypoxia in KO mice (58.6+/-1.5 mm Hg) than in WT animals (76.1+/-3.2 mm Hg). Consequently, in a separate group of mice, we stabilized and matched MABP during hypoxia. Hypoxic hyperemia was attenuated by 38% (P<0.05) in KO animals whose MABP was uncontrolled, and by 81% (P<0.05) in KO animals whose MABP changes were matched to the MABP in the hypoxic WT mice. In animals treated with adenosine antagonists, hypoxic hyperemia was decreased by 44% to 48% (P<0.05) in WT mice, but was without effect in KO mice. We conclude that adenosine via A2aR is responsible for a significant proportion of the hyperemia during hypoxia.

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.

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.

Transient cerebellar mutism caused by bilateral damage to the dentate nuclei after the second posterior fossa surgery. Case report.

The authors report on the case of a 6-year-old boy who underwent resection of a midline cerebellar tumor. The boy was able to speak fluently after the operation. Magnetic resonance (MR) imaging showed that the right dentate nucleus had been partially removed along with the tumor, but that the left dentate nucleus remained with the residual tumor. A second operation was performed to remove the residue, after which the child suffered mutism. Three weeks post-surgery, he could only communicate through gestures. He started speaking I week later and regained normal speech 2 months after the operation. Final MR imaging revealed gross-total removal of the tumor and dentate nucleus on the injured left side. The cerebellar mutism was considered to have been caused by bilateral damage to the dentate nuclei and not by unilateral damage.

Characteristics of distal posteroinferior cerebellar artery aneurysms.

OBJECTIVE: Distal 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. METHODS: All 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. RESULTS: In 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. CONCLUSION: This 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.