gms | German Medical Science

Objective: The presence of peritumoral edema in skull base meningiomas correlates with tumor features, complexity of surgery and outcome. 5-38% of vestibular schwannomas (VS) may also present with peritumoral edema on MRI. Goal of the current study was to evaluate the effect of preitumoral edema on VS surgery and outcome, which up to now has not been evaluated systematically.

Method: Retrospective study of an institutional VS database. Exclusion criteria were previous surgery, radiosurgery and NF-2. We performed a correlative analysis of the presence and severity of edema to the following parameters: operative difficulty, tumor adhesion, tumor vascularity, presence/ absence of tumor capsule, tumor pathology, functional outcome and complication rate. These parameters were than compared to those in VS of similar size without peritumoral edema (Group B).

Results: 30 patients (30/605 pts. or 5%) presented with peritumoral edema. Their epidemiological and clinical characteristics correlated to tumor size. Complete resection was achieved in all patients in Group A (vs. 97% in the control group B). The surgeon did not find difference in the operative difficulty in patients with/without edema. All tumors were WHO grade 1. A significant difference was found, however, in the frequency of hypervascular VS: 47% in Group A vs. 7% in the overall group (p<0.05). Correspondingly, the postoperative hemorrhage rate was significantly higher in Group A (10%) than in in the control Group B (1%) (p<0.05). The functional outcome in both groups was similar.

Conclusions: The presence of peritumoral edema does not correlate to operative difficulty, rate of complete tumor removal and functional outcome. VS with peritumoral edema are significantly more frequently hypervascular. Hemostasis in such patients should be particularly meticulous because of the higher risk of postoperative hemorrhage in the tumor bed.