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Neurovascular relationships of the sphenoid sinus

A microsurgical study

Kiyotaka Fujii, Steven M. Chambers, and Albert L. Rhoton Jr.

✓ The increasing use of the transsphenoidal approach to sellar tumors has created a need for more detailed information about the neurovascular relationships of the sphenoid sinus. To better define this anatomy, 25 sphenoid sinuses were examined in cadavers, with attention to the neural and vascular structures in the lateral wall of the sinus. Three structures produced prominent bulges into the lateral wall of the sinus; they were 1) the optic nerves, 2) the carotid arteries, and 3) the maxillary branches of the trigeminal nerve. Over half of these structures had a bone thickness of less than 0.5 mm separating them from the sphenoid sinus, and in a few cases, they were separated by only sinus mucosa and dura.

1) The optic canals protruded into the superolateral part of the sphenoid sinus in all except one side of one specimen. In 4% of the optic nerves, only the optic sheath and sinus mucosa separated the nerves from the sinus, and in 78%, less than a 0.5-mm thickness of bone separated them. 2) The carotid arteries produced a prominent bulge into the sphenoid sinus in all but one side of one specimen. In 8% of the carotid arteries there were areas where no bone separated the artery and the sinus. 3) The maxillary branches of trigeminal nerves bulged into the inferolateral part of the sphenoid sinus in all except one side of two specimens. One side of one specimen had no bone, and 70% had less than a 0.5-mm thickness of bone separating the nerve from the sinus. The importance of these findings in transsphenoidal surgery is reviewed.

In Journal of Neurosurgery Volume 50: Issue 1 (Jan 1979)

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Microsurgical anatomy of the choroidal arteries: Lateral and third ventricles

Kiyotaka Fujii, Carla Lenkey, and Albert L. Rhoton Jr.

✓ The microsurgical anatomy of the arteries supplying the choroid plexus of the lateral and third ventricles was examined in 50 formalin-fixed cerebral hemispheres using × 3 to × 20 magnification. There was marked variation in the area of choroid plexus supplied by the choroidal arteries; however, the most common pattern was for the anterior choroidal artery (AChA) to supply a portion of the choroid plexus in the inferior horn and part of the atrium; the lateral posterior choroidal artery (LPChA) to supply a portion of the choroid plexus in the atrium and posterior part of the temporal horn and body; and the medial posterior choroidal artery (MPChA) to supply the choroid plexus in the roof of the third ventricle and a portion of that in the body of the lateral ventricle. The LPChA's and MPChA's occasionally sent branches to the choroid plexus on the contralateral side. The most frequent neural branches of the three choroidal arteries were as follows: AChA branches to the optic tract, cerebral peduncle, temporal lobe, and lateral geniculate body; LPChA branches to the thalamus, geniculate bodies, fornix, and cerebral peduncles; and MPChA branches to the thalamus, pineal body, cerebral peduncle, and tegmentum of the midbrain. Each of the choroidal arteries was divided into a cisternal and plexal segment. The cisternal segments were the most common site of origin of neural branches, but they also gave rise to some plexal branches. The plexal segments occasionally gave rise to neural branches.

In Journal of Neurosurgery Volume 52: Issue 2 (Feb 1980)

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Microsurgical anatomy of the choroidal arteries Fourth ventricle and cerebellopontine angles

Kiyotaka Fujii, Carla Lenkey, and Albert L. Rhoton Jr.

✓ The microsurgical anatomy of the arteries supplying the choroid plexus in the fourth ventricle and cerebellopontine angles was examined under × 3 to × 20 magnification in brains from 25 adult cadavers. In the most common pattern, the branches of the anterior inferior cerebellar artery (AICA) supplied the portion of the choroid plexus in the cerebellopontine angle and adjacent part of the lateral recess of the fourth ventricle, and the posterior inferior cerebellar artery (PICA) supplied the choroid plexus in the roof and medial part of the lateral recess of the fourth ventricle. The superior cerebellar artery (SCA) gave rise to a choroidal branch in only one brain. The choroid plexus on each side of the midline was divided into a medial and a lateral segment. Each segment was considered two parts to facilitate the description of its blood supply. The medial segment, located in the roof of the fourth ventricle, was divided into a rostral or nodular part, and a caudal or tonsillar part. The lateral segment, located in the lateral recess of the fourth ventricle and cerebellopontine angle, was separated into a medial or peduncular part, and a lateral or floccular part. The AICA most commonly supplied all the floccular part and the lateral portion of the peduncular part, and the PICA most commonly supplied all of the tonsillar and nodular parts, and the medial portion of the peduncular part.

In Journal of Neurosurgery Volume 52: Issue 4 (Apr 1980)

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Stereotactic radiosurgery as adjuvant treatment for residual solitary fibrous tumor

Case report

Kuniaki Nakahara, Masaru Yamada, Satoru Shimizu, and Kiyotaka Fujii

✓ This 50-year-old woman presented with headache and visual disturbance. Neuroimaging results demonstrated a well-demarcated tumor attached to the falx cerebri near the transverse sinus, and the lesion was subtotally removed. Based on histological and immunohistochemical evaluation, a solitary fibrous tumor (SFT) was diagnosed. During the next 32 months, the size of the residual tumor increased slightly at the transverse sinus. Stereotactic radiosurgery (SRS) was performed as an adjuvant treatment. Over the course of the next 4 years the tumor decreased in size. The authors suggest that SRS constitutes good adjuvant treatment for regrowing residual SFTs not amenable to reoperation.

In Journal of Neurosurgery Volume 105: Issue 5 (Nov 2006)

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Intracranial vertebral artery dissection with subarachnoid hemorrhage: clinical characteristics and outcomes in conservatively treated patients

Masaru Yamada, Takao Kitahara, Akira Kurata, Kiyotaka Fujii, and Yoshio Miyasaka

Object. Intracranial vertebral artery (VA) dissection with subarachnoid hemorrhage is notorious for frequent rebleeding and a poor prognosis. Nevertheless, some patients survive with a good final outcome. The factors associated with the prognosis of this disease are not fully understood and appropriate treatment strategies continue to be debated. The authors retrospectively evaluated the clinical features of conservatively treated patients to elucidate the relationship between the clinical and angiographic characteristics of the disease and final outcomes.

Methods. This study includes 24 patients who were treated by conservative methods between 1990 and 2000. Conservative treatment was chosen because of delayed diagnosis, poor clinical condition, or anatomical features such as bilateral lesions and contralateral VA hypoplasia.

Of nine patients with an admission Hunt and Kosnik Grade I or II, eight had good outcomes (mean follow-up period 8 years and 4 months). All 15 patients with Grade III, IV, or V died and in 10 of these the cause of death was rebleeding. Among the 24 patients, 14 suffered a total of 35 rebleeding episodes; in 10 (71.4%) of these 14 patients rebleeding occurred within 6 hours and in 13 (93%) within 24 hours. Compared with the survivors, there was a female preponderance (0.022) among patients who died. These patients also had significantly shorter intervals between onset and hospital admission (p = 0.0067), a higher admission Hunt and Kosnik grade (p = 0.0001), a higher incidence of prehospitalization (p = 0.0296) and postadmission (p = 0.0029) rebleeding episodes, and a higher incidence of angiographically confirmed pearl-and-string structure of the lesion (p = 0.0049).

Conclusions. In our series of preselected patients, poor admission neurological grade, rebleeding episode(s), and lesions with a pearl-and-string structure were predictive of poor outcomes. Our findings indicate that patients with these characteristics may be candidates for aggressive attempts to prevent rebleeding during the acute stage. Patients without these characteristics may be good candidates for conservative treatment, especially those who survive the acute phase without rebleeding.

In Journal of Neurosurgery Volume 101: Issue 1 (Jul 2004)

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Regression of an atlantoaxial degenerative articular cyst associated with subluxation during conservative treatment

Case report and review of the literature

Takao Sagiuchi, Satoru Shimizu, Ryusui Tanaka, Shigekuni Tachibana, and Kiyotaka Fujii

✓ The presence of an atlantoaxial degenerative articular cyst is rare; when present this lesion extends posteriorly to the dens, causing cervicomedullary compressive myelopathy. The authors describe a symptomatic case of this lesion associated with atlantoaxial subluxation in a 76-year-old man. The patient’s neurological symptoms resolved and corresponded to a reduction in the size of the cyst. After 8 months of continued conservative treatment, in which the patient wore a Philadelphia collar, the cyst spontaneously regressed. Subsequently, a C1–2 posterior fusion was performed to treat the atlantoaxial subluxation.

In Journal of Neurosurgery: Spine Volume 5: Issue 2 (Aug 2006)

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Flat arrangement of the cauda equina in Chiari malformation

Case illustration

Satoru Shimizu, Takao Sagiuchi, Takahiro Mochizuki, Shinichi Kan, and Kiyotaka Fujii

In Journal of Neurosurgery: Spine Volume 6: Issue 4 (Apr 2007)

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Obstruction of a Codman-Hakim programmable valve by a migrating pressure control cam

Case report

Satoru Shimizu, Satoshi Utsuki, Sachio Suzuki, Hidehiro Oka, and Kiyotaka Fujii

✓Although the Codman-Hakim programmable valve is popular, several problems arising from its design have been described. The authors report an additional cause of shunt obstruction in the system. A 6-year-old girl who had received a ventriculoperitoneal shunt with the Codman-Hakim programmable valve system presented with worsening consciousness. The valve proved hard to flush, and emergency revision of the valve was performed. Examination of the extracted valve revealed that the pressure control cam had migrated into the outlet of the valve, thus causing the obstruction. A crack in the plastic housing surrounding the cam suggesting a past impact to the system was also revealed. These factors should thus be kept in mind as potential sources of obstruction of the valve system, especially in patients susceptible to episodes of head impact.

In Journal of Neurosurgery: Pediatrics Volume 103: Issue 3 (Sep 2005)

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Fluorescence diagnosis of tumor cells in hemangioblastoma cysts with 5-aminolevulinic acid

Case report

Satoshi Utsuki, Hidehiro Oka, Kimitoshi Sato, Satoru Shimizu, Sachio Suzuki, and Kiyotaka Fujii

Peritumoral hemangioblastoma cysts are usually composed of fibrous tissue without tumor cells. The authors describe the first case in which fluorescence with 5-aminolevulinic acid (5-ALA) was used to diagnose a hemangioblastoma tumor in a peritumoral cyst wall. A 27-year-old woman with a homogeneous, enhanced nodular lesion in the right hemisphere of the cerebellum underwent surgical treatment. After the nodular lesion was removed, the cyst region was observed with the aid of a semiconductor laser with a peak wavelength of 405 ± 1 nm, which was powered using a fiberoptic cable. The cyst region was visualized with strong fluorescence, which disappeared after tissue removal. The fluorescent cyst consisted of tumor cells. The authors conclude that fluorescence diagnosis performed using 5-ALA can inform the choice of removing hemangioblastoma cysts.

In Journal of Neurosurgery Volume 112: Issue 1 (Jan 2010)

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Motor evoked potential mapping and monitoring by direct brainstem stimulation

Technical note

Satoshi Tanaka, Junko Takanashi, Kiyotaka Fujii, Hiroshi Ujiie, and Tomokatsu Hori

✓Motor evoked potentials (MEPs) by direct brainstem stimulation were generated during 12 neurosurgical operations performed in five posterior fossa tumors, six vertebrobasilar aneurysms, and an arachnoid cyst. The anterior aspect of the brainstem was exposed using a subtemporal approach (in six cases), a presigmoid approach (one case), or a lateral suboccipital approach (five cases). A train of five monopolar 5 to 25 mA pulses was then applied, and MEPs were recorded from the extremities. Motor evoked potentials were recorded in all patients (four mappings and seven monitorings) except in a 12-year-old child who underwent surgery for a posterior cerebral artery aneurysm. Although he experienced postoperative motor palsy, the aneurysm ruptured before electrodes could be placed. Two patients with postoperative motor palsy, one with a clival meningioma and one with a basilar trunk aneurysm, had shown significant decreases in MEP amplitude and even complete disappearance of MEPs during intraoperative brainstem stimulation. Motor evoked potentials elicited by direct brainstem stimulation seem to be an accurate neurophysiological monitoring method during operations around the anterior and lateral aspects of the brainstem.

In Journal of Neurosurgery Volume 107: Issue 5 (Nov 2007)