Artikel
The 2micron continuous wave laser in skull base surgery in children with NF II
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Veröffentlicht: | 16. September 2010 |
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Objective: In vestibular schwannoma surgery in children with NF II, where hearing preservation is the goal of surgery, the often hard and solid tumor consistency and strong adhesions to the cochlear nerve are the two major factors limiting the extent of tumor removal. Any movement of the tumor, any traction can cause deterioration of evoked potentials. The 2micron continuous wave laser combines the high tissue effectiveness of the CO2 laser with the hemostatic capacity of the Nd:YAG laser, however with a maximal tissue penetration of only 1–2 mm. We compared the utility of the 2micron laser enabling touch- and movement-free tumor volume reduction with CUSA and manual removal with tumor forceps under the given pre-conditions of intra-operative AEP preservation
Methods: Two children with NFII and bilateral VS (11y; 13y) underwent decompression of one cochlear nerve by opening of the internal auditory canal (IAC) and partial to subtotal removal of the VS, according to the effect of surgery on AEP monitoring. Tumor size was T1 in one and T3a (Hannover classification) in the other child. One child had an additional recurrent cranicervical junction meningeoma.
Results: The tumors turned out to be firm, very adhesive and it was impossible to remove tissue with the forceps without creating strong traction to the cochlear nerve. CUSA was moderately effective but the tip too bulky. The thin laser fibre however, could be safely moved within the IAC and a bloodless tumor reduction within the IAC in ultimate proximity to cochlear and facial nerves was possible. More than 50% of the tumor volume, that remained after manual/CUSA resection, could be removed. In both children hearing remained at the pre-operative level and facial nerve function was unaffected. In the recurrent meningeoma of the craniocervical junction surrounding the vertebral artery, the 2micron laser was used for reduction/resection of the hard tumor shell around the vertebral artery, which was too hard for CUSA.
Conclusions: The 2micron continuous wave laser seems to be a promising tool for touch- and traction free reduction of small tumor volumes in delicate areas. However meticulous application including continuous water cooling is necessary so as not to surrounding structures. Still lacking is scientific work regarding the extent of the zone with critical heat development in the different tissues during laser application.