Cavernous Malformations: From Frame-Based to ...

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Cavernous Malformations: From Frame-Based to Frameless Stereotactic Localization K. Ungersböck ', M. Aichholzer ', M. Giinthner'. K. Rössfer '. H. Görzer1• W T. Koos'

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An exact surgi cal approach to cavernous malforma-

uoos.to particular those located in area s of critical brain Iuncnon. is important for their m icrosurg ical resectlon without putting to muc h st rain c n the patient. Ouring a two-year perrod . 29 cavemoma resecncns were performed . Stereoteetic guid an ce was performed in 16 cases (55.2 %). Nine cever-

nomas located in the suprate ntonal region were resected using the stereot acnc operating m lcroscope ~ M K M·. w hich rep rese nt s 21.6 % of a tot al of S1 MKM·navigated ope ratio ns;

in one furthe r case systern referencing Iefl ed. The experlence gathe red with this fra meless stereo tecnc wstem ts compared to 01 retrc spectf ve analysis of 5 frame-based stereotecuc cavemoma loca lizations. rrameless stereo tact ic localizati on bes been shown to be sufficien tly ecc urete but more edvantaqecus than frame-ba sed techmq ues in terms of utility, ease of integratio n. and detaued image-guided enetcrmcat informa tion. Softwa re improveme nts beve resulted in 01 high stability of t he frame less st ereotacnc system. • Keywo rds: Stereotactk tecbnrq ues - Image-gu ided resection - Cevemous ang iomas - OCcult vascular ma lformation

irnage-guid ed loca lization possible (8, 11, 16, 24 ). We rep ort our expenence wi th the resecnon of supratenrorial caverno ma s against the background of th e devetopmen t fro m Iram e- based to fram ele ss ste reotee rte loca lization. Methods

Patient population In 01 period of (wo years (öct ober 1994-0ctober 1996 ). 29

cavemoma resecocns w ere per formed at our hos pital. The rnean patienr age was 40.5 years (range 20-74 yeers): 11 of

th e m were males and 18 femates. Patie nt selecnon for t he use of srereotacnc Intra-operative localization was at the surgeon's dtscrenon : su rgical guidance was use d in a to ta l of 16 supratentorial cavemoma resecnons (55.2%). In 5 cases ( 17.2%) operared between Ocrober 1994 and j anua ry 1996. srerectacttc Irarne-based locaüzanon wa s chosen. Afte r t he stereo tactic operati ng microscope MKM hold become ava ilable in Apr il 1995. fram eless srereo recnc local ization of 11 suprarenrenal cavernc rnas (37.9%) wa s performed using this system. Table 1 s ummarizes the c1 inica t dara of the caverno mas targeted wi rf an d without fra me guida nce.

Int ro d uctio n Cavernous angiomas of the brain ar e vascuta r maIfor mano ns d iagno sed mainly by tnrracereb ra l hemorrhages. ne urological dys funcrlo n. and seizu res ( 1.4.6. 10, 17.22.25). W hile t hese angiographica tly not ev ide nt lesion s we re forme rly d iagn osed on ly s po radical1 y, th e introduct ion of MR imag ing, w hich has de ve loped to beco me the method of choice for the evalu at ion of cavem omas. has res ulted in a m arked increase in the num ber of cavemomas d iagnosed. o f repo rts on the ir natu ral courses an d th e rapeutic stwegies ( 1.3.6.9. 10. 13, 21.28). Generally small an d we lldefine d lesions. cavemous angio ma s usually can be reseeted m icrosurgicall y w ithout .:m y prob lems: localiza tion of subcortical or dee p-.sea ted cavemomas. howeve r, may pose problems (7, 14, 17). Therefore, surgical resectio n of cavemomas req uire s their sa fe loca lization in orde r to m inimize tra umatiza tion of adj acent brai n tissu e. ln cri tical brain regio ns in particular, stereotactic guida nce for surgical approach e nhan ce s the safety of sur gical rese