Differences in clinical presentation, intraoperative findings and outcome between petroclival and lateral posterior pyramid meningioma.

Objective: The goal of this study was to determine the impact of the location of the most frequent skull base meningioma of the posterior fossa, i.e. petroclival (PCM) and lateral posterior pyramid meningioma (LPPM) on clinical presentation, surgical treatment and treatment results.

Patients And Methods: We retrospectively reviewed a consecutive series of patients operated on for PCM (n=46) and LPPM (n=32). Uni- and multivariate analyses were performed to identify differences in clinical presentation, surgical treatment and pre-, intra- and postoperative factors of influence upon the outcome parameters: Complications rate, mortality, tumour recurrence/progress, hospital stay, Karnofsky Performance Score (KPS).

Results: At Presentation, the rate of dizziness was higher in LPPM (56% vs. 7%, p<0,001) and trigeminal nerve impairment was more frequent in PCM (50% vs. 3%, p<0,001). Complete tumour resections were more often achieved (91% vs. 39%, p<0,001), and surgery lasted shorter (median: 247 min vs. 500 min, p<0,001) with less blood loss (median: 525 ml vs. 1000 ml, p<0,001) in LPPM compared to PCM. The overall complication rates (73% vs. 31%, p<0,001) as well the rate of irreversible complications (57% vs. 9%, p<0,004) were higher in PCM than in LPPM. The most frequent complications of PCM surgery were eye movement (46% vs. 6%, p<0,001), facial nerve (28% vs. 3%, p<0.02) and swallowing impairments (21% vs. 3%, p<0.02). The perioperative mortality was 11% in PCM and 0% in LPPM patients. In the multivariate analyses, KPS at discharge correlate positively with age (p=0.034) and preoperative KPS (p=0.0048) in LPPM and positively with staged resection (p=0.056) and negatively with the occurrence of surgical complications (p=0,0427) in PCM. Hospitalization time correlated with the blood loss (p<0,001) for PCM, negatively with the preoperative KPS (p=0.0002) for PCM and LPPM and positively with tumour diameter (p=0.0001) and non-surgical complications rate (p=0.0001) for LPPM.

Conclusion: As compared to LPPM, surgical treatment of PCM is associated with higher morbidity and mortality. The outcome of LPPM was primarily influenced by preoperative factors: Patients age, tumour size, preoperative KPS. The outcome of PCM was primarily influenced by intraoperative factors like: blood loss, surgery duration, staged tumour resection and the surgical complications rate.