Site of Dural Attachment and Cranial Nerve Relationships Predict Clinical Outcome in Petrous Meningiomas

Background: Petrous meningiomas (PMs) represent a heterogeneous group of tumors originating in a complex anatomical skull base region. The lack of a shared classification and different adopted surgical strategies makes the interpretation and comparison of the surgical outcome reported in literature often difficult and inaccurate. This study reports the clinical outcomes of PMs operated by a single surgeon using only the retrosigmoid approach (RSA); further, we compare results stratified between different tumor dural attachment patterns.

Methods: Patients surgically treated for PMs using the RSA by the senior author (P.M.) from January 2002 to December 2019 were selected. Patients with incomplete data or with different treatment strategies were excluded. Tumors were classified based on their dural attachment site: (1) posterior petrous meningioma (PPM), lateral to the internal acoustic meatus (IAM); (2) petrous apex meningioma (PAM): between IAM and V CN; (3) petroclival meningioma (PCM): medial to the V CN. Only tumors operated with RSA were included. Recurrence or residual tumors were treated by a second surgery (orbitozygomatic approach) or focused radiation. Clinical and radiographic findings were recorded preoperatively, immediately postoperatively, and at one and 5-year follow-ups. Statistical univariate and multivariate logistic and linear regression analyses were conducted using SPSS 25 (IBM). p-Value ≤0.05 was considered for statistical significance.

Results: One hundred patients were identified. Seventy-seven were female. The mean age at diagnosis was 56.6 years. There were 37 PPMs, 19 PAMs, and 44 PCMs. Mean tumor volume was 45.8 mm³ (24–59 mm³), 43.5 mm³ (25.1–61 mm³), and 38.8 mm³ (20–55 mm³) for PPM, PAM, and PCM, respectively. GTR was achieved in 56.7, 52.6, and 22.2% of PPM, PAM, and PCM, respectively. Three patients underwent a second surgery and 62 focused radiations. The mean KPS at the last follow-up was PPM 94.05, PAM 83.8, and PCM 83.7 (p = 0.003). Two patients died. Rate of new CN deficit was higher in PCM (44.6%; p = 0.004). Compared to PPM, PAM and PCM had worse facial nerve outcomes immediately postoperatively (OR: 19.99, p = 0.011; OR: 36.18, p = 0.003, respectively) and at 5-year follow-up (OR: 5.41, p = 0.071; OR: 11.31, p = 0.011, respectively). Postoperative VIII CN deficit was higher in PAM and PCM compared to PPM (OR: 7.6, p = 0.023, OR: 8.0; p = 0.019). New V CN deficit was highest in PCM (8%; p = 0.008). Persistent V CN deficit at 5-year follow-up was significantly related to Meckel’s cave and supratentorial extension (OR: 28.45, p = 0.0019, OR: 32.48, p = 0.008). Postoperative VI CN deficit was highest in PCMs (31.1%, p = 0.001) and was significantly related to Dorello’s canal and cavernous sinus invasion (OR: 32.48, p = 0.002; OR: 27.45, p = 0.008).

Conclusion: The results of the present study confirm that PPM, PAM, and PCM represent three distinct entities characterized by different and, respectively progressive surgical pitfalls that impact the patients’ clinical outcome. The clinical outcome remains worse for patients harboring PCMs, even if a multimodal treatment strategy is performed. The proposed classification demonstrates to be a reliable tool to predict the clinical outcome in patients harboring petrous and clival meningiomas ([Fig. 1]).

Fig. 1

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Artikel online veröffentlicht:
05. Februar 2024