Article
Custom-tailored transdural anterior transpetrosal approach to the ventral pons and retroclival region
Der modifizierte transdurale anterior transpetrosale Zugang zur ventralen Pons und retroclivalen Region
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Published: | May 4, 2005 |
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Outline
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Objective
The extradural anterior petrosectomy approach to the pons and midbasilar artery has the main disadvantage that the extent of resection of the petrous apex cannot be limited to the necessary minimum since the surgical target field is not visible during bone removal. Unnecessary excessive drilling carries the risk of injury to the internal carotid artery, stato-acoustic organ and 7th and 8th cranial nerve. A custom-tailored transdural anterior transpetrosal approach can potentially avoid these pitfalls.
Methods
A technique for a small transdural anterior petrosectomy was developed. Following a keyhole subtemporal craniotomy and basal opening of the dura the vein of Labbé is first identified and protected. 50-100 ml of CSF are drained at this stage via a spinal catheter. The tent is incised behind the entrance of the trochlear nerve toward the superior petrosal sinus. The sinus is coagulated and divided. The dura is stripped off the petrous pyramid. The petrosal vein often also needs to be coagulated and divided. Drilling starts on the petrous ridge and proceeds laterally and ventrally. The trigeminal nerve is unroofed. The internal acoustic meatus is identified and drilling is continued laterally as needed. The bone of Kawase's triangle toward the clivus can be removed down to the inferior petrosal sinus if necessary. Anterior exposure can be extended to the carotid artery if required. It is only exceptionally necessary to follow the greater superior petrosal nerve toward the geniculate ganglion and to expose the length of the internal acoustic canal.
Results
The modified transdural anterior petrosectomy exposure has been used in 7 patients, 3 pontine cavernomas, 2 midbasilar aneurysm, 1 pontine glioma and 1 dural arteriovenous fistula of the inferior petrosal sinus. In one patient with a midbasilar aneurysm, subcutaneous CSF collection occurred during the postoperative period. No CSF fistula or approach related cranial nerve deficit developed in any of these patients. We did not see retraction injury or venous congestion of the temporal lobe or venous congestion due to the obliteration of the superior petrosal sinus or the petrosal vein.
Conclusions
The custom made transdural anterior petrosectomy appears to be a feasible alternative to the formal extradural approach.