| Background:The petroclival region is a small cisternal space located deeply in the most anterior part of the posterior cranial fossa. In front, it is blocked by the clivus and on the side, by the anterior third of the petrous pyramids and peripetrous elements. Various neurovascular structures pass through this space. The petroclival region is a surgical entity, recognized because of specific diseases, notably petroclival tumors. The term petroclival tumor refers to a lesion originating or inserted in the upper two-thirds of the clivus or the petrous apex, medial to the trigeminal nerve, for example, meningioma, schwannoma, chordoma, epidermoid cyst, chondroma, and so on. Structures close to the clival dura mater are often involved by growing tumor masses in this region and in consequence, the cavernous sinus, the Meckel’s cave, the sphenoidal sinus, the sellar region, the incisure of the tentorium, the porus and the ventral edge of the foramen magnum may be encroached upon and may need to be exposed. It is particularly difficult to expose the endocranial face of the clivus, the vertical aspect of the posterior face of the petrous portion of the temporal bone, the ventral surface of the brain stem, and all the intradural elements of the petroclival region. Special attention should be paid to select suitable surgical approaches according to different types of petroclival tumors, which is important to increase the therapeutic efficacy and decrease the postoperative complications.Objective:1. To investigate the surgical techniques of petroclibal region tumors through preauricular subtemporal keyhole approach, reduce intraoperative adverse events and complications after operation.2. To observe the surgical techniques clinical efficacy.Materials and Method:A retrospective review was performed to analyze the clinical data of 18 patents with petroclibal region tumors who undergone preauricular subtemporal keyhole approach under electrophysiologic monitoring of cranial nerves and brain stem function from January 2012 to September 2014 in our department. The patients’ general information, clinical features, imaging findings, therapeutic methods and effects, and the changes of neurofunction pre-and post-operation were all reviewed retrospectively.Results:All 18 cases underwent the preauricular subtemporal keyhole approach under electrophysiologic monitoring of cranial nerves and brain stem function. In all 18 cases, gross total resection was accomplished in 15 (83.3%) cases, subtotal resection in 2(11.1%) cases, great part in 1 (5.6%) case due to the encompassing of internal carotid artery and the cavernous sinus invasion. Labbe’s vein were reserved in 17 patients, freed in a segment from the cortex in 1 patient. Trochlear nerve was partly wrapped in 16 cases, totally wrapped but can be explored in the initial segment of the cerebellum te ntorium in 1 case, totally wrapped and could not be seen until tumor was partly removed in 1 case. The incision of the cerebellum tentorium was performed posterior to where cranial nerve IV merged and parallel to the superior petrous sinus. Mean hospitalized days were 26 days (ranged from 16 to 64 days).18 patients were followed up for 6 to 26 months. Oculomotor paralysis in 1 patient, who recovered completely 9 days later. Ambiopa in 2 patients,1 recovered completely 4 months later, another 6 months later. Facial hypesthesia in 3 patients, including recovered completely in 2 and recovered to some degree in 1. Facioplegia in 1 patient, who recovered completely 6 months later. There was no CSF leakag, hemiplegia and aphasia cases.Conclusion:1. Preauricular subtemporal keyhole approach combined with electrophysiological monitoring is a reasonable therapy in petroclibal region tumors.2. Microneurosurgical knowledge and technique always play a key role in the maximal tumors resection with the preservation of the nerve function.3. Intraoperative electrophysiologic monitoring of cranial nerves and brain stem function is useful for the protection of neurological function. |
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