Cavernous hemangioma of the mesencephalon: tonsillouveal transaqueductal approach.
OBJECTIVE
Recent advances in microsurgical techniques facilitate surgical resection of brainstem lesions that were previously considered inoperable. In this article we present, for the first time, the tonsillouveal transaqueductal approach to access a progressively symptomatic cavernoma within the depth of the tegmentum of the mesencephalon.


METHODS
A 52-year-old woman presented with a history of slowly progressive right-sided hemiparesis and ataxia. On magnetic resonance imaging, a relatively large cavernoma involving the tegmentum of the mesencephalon was shown. The sylvian aqueduct was patent and there was no secondary ventriculomegaly. The patient underwent surgery via a suboccipital craniotomy and C1 laminectomy. The right tonsillouveal and medullotonsillar spaces were opened to the level of the choroidal point of the posteroinferior cerebellar artery. The tela choroidea was incised from the foramen of Magendie to the telovelar junction. Looking through the aqueduct and at a point 5 mm superior to its inferior inlet, there was a small cherry-like blister protruding into the aqueductal anterior surface. This was used as an entry point to access the cavernoma. The space around the cavernoma was gently dissected and the cavernoma was circumferentially coagulated to shrink it in a concentric manner toward its center.


RESULTS
The total removal of the lesion was achieved and the histopathological findings were consistent with a cavernoma. As a result of noncommunicating hydrocephalus, the patient needed a ventriculoperitoneal shunt. The 1-year postoperative neurological examination was consistent with preoperative findings.


CONCLUSIONS
This report shows, for the first time, direct surgical removal of a cavernous hemangioma in the mesencephalic tegmentum via the aqueduct. This approach adds to contemporary microneurosurgery, respecting functional anatomy and minimizing neurological deficits.
Dammers
Ruben
R
Department of Neurosurgery, Erasmus Medical Center, Rotterdam, The Netherlands. r.dammers@erasmusmc.nl
Delwel
Ernst J
EJ
Krisht
Ali F
AF
D001259:Ataxia / Q000209:etiology; D020295:Brain Stem Neoplasms / Q000473:pathology / Q000601:surgery*; D002531:Cerebellum / Q000033:anatomy & histology / Q000601:surgery; D002535:Cerebral Aqueduct / Q000033:anatomy & histology / Q000601:surgery*; D001270:Cervical Atlas / Q000033:anatomy & histology / Q000601:surgery; D003399:Craniotomy / Q000379:methods; D004564:Electrocoagulation / Q000379:methods; D005260:Female; D020546:Fourth Ventricle / Q000033:anatomy & histology / Q000601:surgery*; D020786:Hemangioma, Cavernous, Central Nervous System / Q000473:pathology / Q000601:surgery*; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology / Q000601:surgery; D007431:Intraoperative Complications / Q000209:etiology / Q000517:prevention & control; D007796:Laminectomy / Q000379:methods; D008636:Mesencephalon / Q000473:pathology / Q000601:surgery*; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D009777:Occipital Bone / Q000033:anatomy & histology / Q000601:surgery; D010291:Paresis / Q000209:etiology; D013681:Tegmentum Mesencephali / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome; D017287:Ventriculoperitoneal Shunt