Preoperative Embolization of Brain Tumors Using a Provocative Test: Evaluating the Safety and Efficacy of Embolization of Test-Positive Vessels.

PURPOSE: The embolization of vessels potentially involved in the vasa nervorum during brain tumor embolization is often a non-aggressive procedure. In this study, we aimed to investigate the safety and efficacy of embolization of vessels with positive provocative test results.

METHODS

Embosphere (Merit Medical Systems, South Jordan, Utah, USA) was the embolization material of choice. A provocative test was performed using 30 mg of 1% lidocaine, with a positive result if neurological symptoms appeared. A size of 500-700 µm was used for positive results and 300-500 µm for negative results. Embolization was performed five to seven days before resection, and contrast-enhanced MRI was performed three to five days after embolization to assess the embolic status.

RESULTS

Provocative tests were performed on 61 vessels from 55 patients. A total of 36 vessels (59.0%) were positive, and 25 vessels were negative. The petrosal branch of the middle meningeal artery and the neuro-meningeal branch of the ascending pharyngeal artery showed particularly high positivity rates (91.7% and 76.5%, respectively). Three patients (8.3%) out of the 36 who underwent embolization of the positive vessels had neurological symptoms after embolization; two had symptoms similar to those observed in the provocative test, and one had different symptoms. All symptoms were mild and transient. The postoperative contrast-enhanced MRI showed that the enhancing effect was attenuated in 18 of the 30 patients (60%) with provocative test-positive vessels.

CONCLUSION

Embolization of provocative test-positive vessels can be performed safely and effectively with a larger Embosphere (500-700 μm).