Quantitative anatomic comparison of the extended pterional transtemporal transtentorial approach and the subtemporal transtentorial approach to the petroclival region.

AIM The anatomic characters and applicability of the extended pterional transtemporal transtentorial (EPTT) approach versus the subtemporal transtentorial (ST) approach for surgical treatment of petroclival tumors were evaluated. MATERIAL AND METHODS Ten sides from five adult Chinese injected cadavers were manipulated using both two approaches. Four deep bony anatomic landmarks were specified in the skull base to create two adjoining triangles that were respectively located in the anterior and posterior petroclival region. The real, projected area and the percentage of the projected area were determined and calculated to compare the deep exposure from the two approaches. RESULTS There was no difference regarding the percentage of the projected area was calculated in the anterior triangles (EPTT, 21.5±12.5%; ST, 28.8±14.9%; p=0.1948), but a significant difference was present in the posterior triangles (EPTT, 74.0±4.5%; ST, 51.5±4.3%; p < 0.01). Compared with the ST approach, the EPTT approach provides an equivalent percentage of projected area in the middle cranial fossa and a wider exposed area in the posterior cranial fossa. CONCLUSION Through anatomic comparative analysis the EPTT approach provides better exposure and is more appropriate than the ST approach for large and giant petroclival tumors predominantly in the posterior cranial fossa with extensive invasion to parasellar structures and the cavernous sinus.