The Pretemporal Transcavernous Anterior Petrosal Approach: A Pathway to the Petroclival Area

Lesions in the petroclival region represent a surgical challenge due to their anatomical location hidden below Meckel's cave and being surrounded by critical neurovascular structures. Occasionally the surgical access to the petroclival area itself may result in surgical morbidity. So, choosing the surgical approach is one of the most important considerations the surgeon must make. The main goal of the surgical approach is to expose the tumor effectively while sparing the cranial nerves and other neurovascular structures. Although the combined petrosectomy (CP) approach has been widely used for petroclival meningiomas, the pretemporal transcavernous anterior petrosal (PTAP) approach has emerged as an alternative approach for reaching the petroclival region.

The authors’ objective is to evaluate their experience in treating petroclival lesions and discuss our results. Furthermore, we sought to analyze the benefits and limitations of the PTAP approach for treating petroclival lesions and try to identify tumor characteristics that may aid the surgeon in choosing the surgical approach.

Between 2015 and 2022, a total of 41 patients with lesions other than acoustic schwannomas and involving the anterior portion of the petrous apex were operated at our institution. Among those patients, we identified 19 (46.34%) patients presenting true petroclival lesions. There were 11 (57.9%) males and 8 (42.1%) females. Median age of the series was 56 years old (range: 27–80). All 19 lesions aroused from the petroclival fissure and were located medially to the trigeminal nerve. There were 14 (76.68%) patients with petroclival meningiomas, 2 (10.52%) chondrosarcomas, 2 (10.52%) epidermoid tumors and 1 (5.26%) trigeminal schwannoma.

PTAP approach was employed in 14 cases (73.68%) and CP was performed in 5 cases (26.31%). Gross total resection was achieved in 5 cases (26.31%), near total resection in 9 cases (47.36%) and partial resection in 5 (26.31%). Although gross total resection was more frequent in the PTAP approach than in the CP (5 vs. 0 cases) no statistical differences were found (p = 0.1). Tumors operated by means of the PTAP approach had no extension posterior to VII–VIII complex while 60% of tumors operated by means of CP had (p < 0.05). There were no significant differences in contralateral tumor extension or posteromedial displacement of cerebral peduncle, related to surgical approach.

Nine patients (47.36%) experienced new postoperative cranial nerve palsies, being the most frequently affected the sixth cranial nerve. However, 6 of them (66.66%) experienced full recovery of the postoperative deterioration. Only 3 patients (15.78%) presented permanent cranial nerve deficits.

Four patients (21.05%) presented surgical related complications, consisting in two cases of wound infection, one cerebrospinal fluid leak and one lobar hematoma that required surgery to be stopped and emergent hematoma evacuation.

PTAP is a complex skull base approach that requires surgical experience and deep anatomical knowledge but provides a wide corridor to the pretemporal, cavernous sinus, Meckel's cave and petroclival areas. The PTAP approach allowed us to safely treat large tumors that do not exceed the VI-VIII complex posteriorly.

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Artikel online veröffentlicht:
01. Februar 2023