The Anatomic Study On Extented Pterional Transtemporal Transtentorial Approach For Surgery To Petroclival Region

Part ⅠThe Study On the Microsurgical Anatomic of Extended Pterional Transtemporal Transtentorial ApproachObjective:To study on the microsurgical anatomic of the extended pterional transtemporal transtentorial approach and provide anatomical basis for surgical treatment of petroclival tumors.Methods:Five cases (10sides) of Chinese adult cadaver heads fixed by10%formalin were dissected using the extended pterional transtemporal transtentorial approach, The exposure range of the petroclival region were observed under microscope, the relative anatomical structures were measured, described and analyzed. Then the distances of important bony structures of skull base in ten dry cadaver skulls were measured.Results:The extended pterional transtemporal transtentorial approach can fully reveal the anterior and posterior clinoid process, cavernous sinus, oculomotor nerve, trochlear nerve, trigeminal nerve, superior cerebellar artery, posterior cerebral artery, basilar artery, superior petrosal sinus, ventral lateral brainstem, petrous apex and arcuate eminence etc.Conclusion:The extended pterional transtemporal transtentorial approach applies to the petroclival tumors which invaded to the cavernous sinus and meckel’s cave. It also provides a satisfactory operability to the petroclival tumors which were mainly located in the posterior fossa. Part ⅡQuantitative Anatomic Comparison ofExtended Pterional Transtemporal Transtentorial Approach and Traditional Subtemporal Approach to the petroclival regionBackground:The anatomic characters and applicability of the extended pterional transtemporal transtentorial (EPTT) approach versus the traditional subtemporal (TS) approach were evaluated for surgery to petroclival tumors.Methods:Ten sides from five adult Chinese injected cadavers were dissected using both two approaches. Four deep bony anatomic landmarks in skull base were specified to create two adjoining triangles which were respectively located in the anterior and posterior petroclival region. Six external opening points in skull surface were composed the bone window planes of two approaches. The real, projected areas and the percentage of the projected areas were collected and calculated to compare the exposure area in the two approaches.Results:In the anterior triangles of middle cranial fossa, there were no significant difference in the percentages of projected areas between the two approaches (P=0.1948). But in the posterior triangles of posterior cranial fossa, the percentages of projected areas for the TS approach were significant smaller than the EPTT approach (P<0.01). Compared with TS approach, the EPTT approach provides equivalent percentage of projected areas in middle cranial fossa and a wider visual field to manipulate the tumors in posterior cranial fossa.Conclusions:the EPTT approach is suitable for the large petroclival tumors with premodinantly in middle cranial fossa or premodinantly in posterior cranial fossa and extensive invasion in middle cranial fossa.