The Microsurgery Anatomy And Clinical Application Of Operative Approach To The Petroclival Region

Objective:Through cadaveric head anatomy and operative approach simulation on cadaveric head, the current operative approach to the petroclival region was analyzed, summarized and improved so as to obtain an optimal operative approach.Method:The adult cadaveric head preserved with 10% formalin was dissected under the microscope and the mark and location of important bone structures were further determined. The shape, distribution of skull base vascular and its relationship with cranial nerve and brainstem were illustrated and the relevant distance was measured. The improved tempoccipital transtentorial and infratemperal approach was simulated on cadaveric head and compared with the traditional presigmoid approach.Results:1. It was put forward that the improved tempoccipital transtentorial and infratemperal approach could basically lock the bone windows of the combined approaches above and below the cerebelli through two keyholes (front rake of bregmatomastoid suture and 4.67mm before and under the asterion).2. It was put forward that the incision of the traditional presigmoid approach be used to create the incision of the improved tempoccipital transtentorial and infratemperal approach. 3. It was put forward that the front rake of bregmatomastoid suture be the keyhole of tempoccipital skull dissection, thus the bone window area could be reduced.4. It was put forward that the front rake of bregmatomastoid suture be used to judge the position of the upper margin of presigmoid rotating angle.5. It was put forward that the front rake of bregmatomastoid suture combining with asterion can be the two keyholes of combined skull dissection above and below the cerebelli, which can prevent the whole exposure of sigmoid sinus and reduce its damages.6. It was put forward of the selecting principles of individualized operative approach of petroclival region meningioma.Conclusions:(1) The bone windows of the combined approaches above and below the cerebelli can be basically locked through the two keyholes (front rake of bregmatomastoid suture and 4.67mm before and under the asterion). (2) In respects of the maximum operative view and operating depth, the improved tempoccipital transtentorial and infratemperal approach had no obvious differences with presigmoid approach ((P>0.05) as long as the infratemperal inner side part and the middle bone were removed. (3) The bone window area of the improved tempoccipital transtentorial and infratemperal approach was obviously decreased compared with that of presigmoid approach (P<0.05). (4) The exposed length of the brain stem ventral gap of the improved tempoccipital transtentorial and infratemperal approach was obviously bigger than that of presigmoid approach. While the angle needed to open lobi temporalis in middle ventral part of pon was obviously smaller than that of presigmoid approach (P<0.05). (5) The incision of the traditional presigmoid approach was used to create the incision of the improved tempoccipital transtentorial and infratemperal approach. (6) The front rake of bregmatomastoid suture was taken as the keyhole of tempoccipital skull dissection, thus the bone window area could be reduced. (7) The improved tempoccipital transtentorial and infratemperal approach exposed the base of petroclival region tumor well. It can stop the tumor blood supply earlier, reduce the tumor area, soften the texture and reduce the blood, thus the safety of operation could be enhanced. (8) The improved tempoccipital transtentorial and infratemperal approach was easier and safer than presigmoid approach. The former invades minimally and is a flexible operative approach of treating petroclival region tumor.