Resection of C6 gliomas in rats with the aid of the waterjet technique

• C6 glioma tumor resection was performed in rats with ‘standard’ microsurgical technique or surgical resection with the waterjet dissection device.
• Resection radicality of both techniques was compared with regard to the amount of remaining tumor cells by histological analysis. Additionally, the survival after tumor resection was compared.
• In an experimental setting, waterjet dissection revealed a better resection radicality. Although no difference in time of survival was found, the technique might contribute to a better resection radicality – and a better outcome – in human gliomas as well.

ObjectivesWhile clinically the safety and efficacy of waterjet resection of brain tumors have been shown, evidence that waterjet dissection improves tumor resection radicality in comparison with conventional techniques is still missing. In the present study, resection radicality and tumor-free long-term survival of both techniques were evaluated in a C6-glioma model.Material and methodsFifty-thousand C6-glioma cells were stereotactically transplanted in the left frontal lobe of 100 male Sprague-Dawley rats. After MRI-scanning for evaluation of tumor extension, microsurgical tumor resection was performed with conventional techniques (n = 50) or with the waterjet dissector at pressures of 6 bar (n = 50). Twenty-five animals of each group were sacrificed after surgery for histological analysis. For analysis of survival after tumor resection, twenty-five animals of each group were followed-up to analyze tumor-free survival using the Kaplan Meier method.ResultsIn the waterjet group, the resection cavity was free of C6-tumor cells in 10/25 (40%) rats showing a trend (p = 0.3) towards better resection radicality compared to the rats that were treated conventionally (7/10; 28%). R1-resection with up to 250C6 cells/object slice was found in 14/25 (56%) rats after waterjet dissection compared to 6/25 (24%) rats treated conventionally showing significance (p < 0.01). Probability of survival was 38% after 2 weeks and 20% after 6 months in the waterjet group compared to 30% and 16% respectively in the conventional group. Diffuse tumor cell spreading with possible influence on survival was shown in 47/50 rats.ConclusionIn this experimental model, waterjet tumor resection did reveal significantly better resection radicality compared to the conventional technique. Although a direct transfer of these results to human glioma surgery is prohibited, the waterjet technique might contribute to the best possible resection radicality in human gliomas. Nevertheless, tumor cell spreading remains a major problem. Further studies have to address that the surgical results – in deed – improve the postoperative outcome.