Comparative study of retrosigmoidal and presigmoidal approaches for minimally invasive exposure of jugular tubercle using a virtual reality technique

Qian Zenghui; Tang Ke; Liu Aihua

doi:10.11850/j.issn.1009-122X.2016.06.011

Abstract：Objective To quantitatively compare microanatomical features of minimally invasive exposure of jugular tubercle via retrosigmoidal and presigmoidal approaches based on anatomy model of virtual reality. Methods CT and MRI scans were performed on 15 adult cadaver heads (30 laterals). Then, image data was inputted into virtual reality system to establish three-dimensional anatomy model of the posterior cranial fossa. Minimally invasive routes of retrosigmoidal and presigmoidal approaches were simulated by selecting osseous landmarks on the calvaria and skull base. Anatomic exposures in above two surgical trajectories were observed and measured. A statistical comparison was performed by paired t test. Results Craniotomy via retrosigmoidal approach was performed below the transverse sinus. The route involved the cerebellum and anterior inferior cerebellar artery (AICA). Then, the route exposed the glossopharyngeal nerve, vagus nerve, accessory nerve and inferior petrosal sinus. Surgical route of presigmoidal approach involved drilling of the osseous structures through the mastoid, and the accessory nerve when arrived at the jugular tubercle through the internal jugular vein and inferior part of jugular bulb. Measuring showed volumes of the surgical route and lower cranial nerves were larger in the retrosigmoidal approach than in the presigmoidal approach. The volumes of the osseous structures and veins were larger in the presigmoidal approach than in the retrosigmoidal approach. All these differences reached statistical significance (P<0.05). The volume of the cerebellum and AICA involved in retrosigmoidal approach was 2750.50 ± 123.27 mm3 and 78.72 ± 1.75 mm3 respectively. The presigmoidal approach did not involve above structures. Conclusions Retrosigmoidal approach is helpful to expose the lower cranial nerves, and cerebellum and AICA should be protected during the exposure. The procedure of jugular tubercle exposure through presigmoidal approach will be confined by operation of petrous bone drilling and sinus protection. The presigmoidal approach is suitable for treating the lesion involving jugular foramen.