True petroclival meningiomas: proposal of classification and role of the combined supra-infratentorial presigmoid retrolabyrinthine approach

BACKGROUND: The evolution of the surgical treatment of petroclival meningiomas (PMs) has led to a tendency to abandon complex petrous approaches and return to “less-aggressive” skull base approaches. OBJECTIVE: To propose a classification of PMs and establish the role of the combined supra-infratentorial presigmoid retrolabyrinthine (CSIPR) approach in the treatment of PMs rigorously matching the anatomical definition. METHODS: A retrospective analysis was conducted of 51 cases of PMs strictly adhering to the anatomical definition who were operated on from January 1990 to December 2011. On the basis of the different patterns of growth from a common anatomical region of origin, a classification of PMs in 4 groups is proposed. RESULTS: Gross total resection was achieved in 32 patients (63%) and subtotal resection (at least 90% tumor volume removal) in 14 patients (27%). Each of the 4 groups of the proposed classification lends itself to be removed by a distinct surgical approach. Statistical analysis confirmed that such group-approach pairings significantly correlate with radical surgical removal (P < 0.001). Despite the high incidence of early postoperative complications, at late follow-up 82% of patients were free of significant postoperative neurological deficits (95% confidence interval: 70-90). Comparable neurological improvement was observed limited to cases treated by CSIPR (P = 0.60). CONCLUSIONS: For each PM group, the most suitable approach was identified in terms of surgical radicality and low postoperative morbidity. CSIPR can be considered the approach of choice for the most frequent group of PMs in our series. We believe that the CSIPR remains a valuable option for the treatment of PMs.