Repermeation of partially embolized cerebral arteriovenous malformations: A clinical, radiologic, and histologic study

PURPOSE: To describe the pattern and time course of embolization-related tissue lesions and repermeation of the intranidal cast after endovascular embolization of cerebral arteriovenous malformations (AVMs) with N-butyl cyanoacrylate (NBCA), METHODS: We retrospectively reviewed the records of 26 patients who were treated by endovascular embolization with NBCA and subsequent surgical extirpation to look for embolization-related tissue lesions and repermeation of the cast. A residual flow through the malformation was identified on preoperative angiograms in every case. RESULTS: Pattern and time course of embolization-related tissue lesions were typical, Until 3 months after embolization, repermeation of embolized structures did not occur, In contrast, repermeation was found in every patient who had surgery later than 3 months after the first embolization (n = 13; 50%). In these cases, histologic examination of the resected nidus disclosed capillary structures inside the lumen of embolized vessels. Capillaries were traced immunohistochemically with antibodies against membrane-bound factor VIII, No parameter other than the interval between the first embolization and surgery was found to relate to the repermeation of the cast. CONCLUSION: Intranidal recapillarization can occur later than 3 months after the first embolization with NBCA if total and solid casting of the nidus was not accomplished.