Anatomic research of suboccipito-retrosigmoidal approach for minimally invasive exposure of facial-acoustic nerve complex utilizing virtual reality skill

Abstract

Objective To discuss microanatomy features of facial-acoustic nerve complex in suboccipito-retrosigmoidal minimally invasive approach based on virtual reality image model. Methods CT and MRI scans were performed to 5 adult cadaver heads, and then, image data was inputted into Vitrea virtual reality system to establish three-dimensional anatomy model of facial-acoustic nerve complex. Suboccipito-retrosigmoidal approach was simulated by selecting osseous landmark points on the calvaria and skull base. Anatomic exposures in surgical trajectory were observed and measured following minimally invasive design. Statistical comparison was launched by paired t test. Results Routes simulating suboccipito-retrosigmoidal approach for exposure of facial-acoustic nerve complex passed under the inferior edge of transverse sinus. Spacial sequence of nerves and vessels in the route was displayed clearly. Vertebral artery and posterior inferior cerebellar artery did not show in the route. Cerebella, lower cranial nerves, anterior inferior cerebellar artery, facial-acoustic nerve complex were exposed successively in route before minimally invasive design. Then, lower cranial nerves pierced the jugular foramen at the site between the jugular bulb and inferior petrosal sinus. Minimally invasive route was higher than that before minimally invasive design and involved cerebella, anterior inferior cerebellar artery and facial-acoustic nerve complex successively. Lower cranial nerves and jugular bulb were not shown in minimally invasive route. Measure and comparative analysis showed that volumes of route (t = 36.331, P = 0.000) and cerebella (t = 16.775, P = 0.000) involved before minimally invasive design were more than that after minimally invasive design with statistically significant difference. Comparison did not show significant differences for the volumes of facial-acoustic nerve complex (t = 1.680, P = 0.127) and anterior inferior cerebellar artery (t = 1.278, P = 0.233) between routes before and after minimally invasive design. Conclusions Minimally invasive routes of suboccipito-retrosigmoidal approach can reduce surgical injury without sacrifice of anatomic exposure for facial-acoustic nerve complex.

doi: 10.3969/j.issn.1672-6731.2014.06.008