Transmaxillary approach to the anterior cavernous sinus: a microanatomic study.

OBJECTIVE: Several approaches to expose the anterior cavernous sinus have been used, such as frontotemporal, orbitofrontal, anterior subtemporal, and various transfacial approaches. In an effort to gain exposure to the anterior cavernous sinus without necessitating a craniotomy or wide transfacial exposure, the authors in the present study have developed a transmaxillary approach to the cavernous sinus. METHODS: The approach was developed using data obtained by performing 24 cadaveric dissections. Using a sublabial incision to expose the maxilla, maxillotomy is performed and the course of the infraorbital nerve is identified as a guide to the maxillary branch of the trigeminal nerve. After an osteotomy of the posterior sinus wall and pterygoid plate, the foramen rotundum is identified, which lies a mean of 10 mm from the posterior wall of the maxilla. A superomedial enlargement of the foramen rotundum is then undertaken to ultimately expose the anterior cavernous sinus. RESULTS: This technique offers access to all cavernous cranial nerves, as well as the entire course of the anterior loop of the internal carotid artery to the origin of the ophthalmic artery. With a mean operative range of 38 mm from the posterior wall of the maxilla to the anterior loop of the internal carotid artery, this approach offers adequate exposure with a short operative distance. CONCLUSION: The approach may be useful in limited exposure of tumors of the anterior cavernous sinus and some intracavernous vascular lesions.

Embolization of neurosurgical lesions involving the ophthalmic artery.

OBJECTIVE: A number of anteriorly located cranial base and extracranial lesions receive their vascular supply wholly or in part from the ophthalmic artery, and embolization of the ophthalmic artery can be helpful in the management of these lesions, either as the primary treatment or as an adjunct to surgery. We present situations in which the embolization of lesions involving the ophthalmic artery was performed to effect a partial or total cure of the lesion. METHODS: Twelve patients underwent a total of 15 embolization attempts on lesions involving the ophthalmic artery. Four patients had arteriovenous malformations of the orbit, four had dural arteriovenous fistulae, two had orbital meningiomas, one had a planum sphenoidale meningioma, and one had a juvenile nasal angiofibroma. In each case, a Tracker No. 18 microcatheter (Target Therapeutics, Inc., Fremont, CA) was navigated into the ophthalmic artery using a steerable guidewire and digital road mapping. Embolic agents included polyvinyl alcohol particles ranging from 350 to 1500 microm in diameter, 2-mm platinum microcoils, and n-butyl-cyanoacrylate. In 12 of 15 cases, lidocaine and amytal provocation tests were conducted before any attempt at embolization to assess the role of the ophthalmic artery in vision. RESULTS: Embolization was successfully performed in the 14 situations in which it was attempted. Positive results of two lidocaine/amytal tests were noted. In one case, embolization was not attempted. In the other case, a larger caliber embolic agent (2-mm platinum coils) was used. A single transient decrease in visual acuity lasting 4 days was the only embolization-related complication. CONCLUSION: Proper case selection, judicious use of embolic agents, and use of provocative testing can result in safe embolization of lesions supplied by the ophthalmic artery.

Reoperative management of intracranial aneurysms.

Nineteen patients underwent 20 operative procedures for the treatment of recurrent or residual aneurysms. There were 13 small, three large, and four giant lesions; with one exception, all were in the anterior circulation. Five individuals presented with recurrent subarachnoid hemorrhage, six were referred for symptoms of mass effect, and nine were known to have had inadequate treatment at the time of the initial operative procedure. The average time interval from initial treatment to either recurrent subarachnoid hemorrhage or compressive effects was 10.5 and 9.75 years, respectively. No deaths resulted from the reoperative procedures. Two patients suffered moderate disability and one had severe disability. Malpositioned or slipped clips, intraoperative rupture, and inadequate exposure were responsible for 75% of the initial operative failures. The technical difficulty of the reoperative procedure correlated with the length of time between initial and reoperative treatment, the presence of clips and coating agents, and the complexity of the lesion. A classification scheme for preoperative planning and case selection is proposed based on the technical adjuncts required for reoperative aneurysm procedures.