Follow-up imaging to detect recurrence of surgically treated pediatric arteriovenous malformations

Abstract

Object The true postoperative incidence of arteriovenous malformation (AVM) recurrence in the pediatric population remains largely unreported. Some literature suggests that delayed imaging studies should be obtained at 6 months to 1 year after negative findings on a postoperative angiogram. The aim of this study was to describe the timing of AVM recurrences after resection and the neuroimaging modalities on which the recurrences were detected. Methods This study was performed in a retrospective cohort of all pediatric patients treated surgically for AVM resection by a single neurosurgeon between 2005 and 2010. Patients were followed after resection with MR angiography (MRA) or conventional angiography, when possible, at various time points. A visual scale for compactness of the initial AVM nidus was used, and the score was correlated with probability of recurrence after surgery. Results A total of 28 patients (13 female, 15 male) underwent an AVM resection. In 18 patients (64.3%) an intraoperative angiogram was obtained. In 4 cases the intraoperative angiogram revealed residual AVM, and repeat resections were performed immediately. Recurrent AVMs were found in 4 children (14.3%) at 50, 51, 56, and 60 weeks after the initial resection. Recurrence risk was 0.08 per person-year. No patient with normal results on an angiogram obtained at 1 year developed a recurrence on either a 5-year angiogram or one obtained at 18 years of age. All patients with recurrence had a compactness score of 1 (diffuse AVM); a lower compactness score was associated with recurrence (p = 0.0003). Conclusions All recurrences in this cohort occurred less than 15 months from the initial resection. The authors recommend intraoperative angiography to help ensure complete resection at the time of the surgery. Follow-up vascular imaging is crucial for detecting recurrent AVMs, and conventional angiography is preferred because MRA can miss smaller AVMs. One-year follow-up imaging detected these recurrences, and no one who had negative results on an angiogram obtained at 1 year had a late recurrence. However, not all of the patients have been followed for 5 years or until 18 years of age, so longer follow-up is required for these patients. A lower compactness score predicted recurrent AVM in this cohort.