Postoperative intraspinal subdural collections after pediatric posterior fossa XXXX resection: incidence, imaging, and clinical features.

@entity1 @entity6804 @entity3976 @entity1276 @entity5 @entity3
BACKGROUND AND PURPOSE: Postoperative intraspinal subdural collections in @entity1 after posterior fossa @entity5 resection may temporarily hinder @entity3 detection by MR imaging or CSF analysis, potentially impacting therapy. We investigated the incidence, imaging and clinical features, predisposing factors, and time course of these collections after posterior fossa @entity5 resection. MATERIALS AND METHODS: Retrospective review of postoperative spine MRI in 243 @entity1 (5.5    4.6 years of age) from our clinical data base postresection of @entity6804 from October 1994 to August 2010 yielded 37 (6.0    4.8 years of age) subjects positive for postoperative intraspinal subdural collections. Their extent and signal properties were recorded for postoperative (37/37), preoperative (15/37), and follow-up spine (35/37) MRI. Risk factors were compared with age-matched internal controls (n = 37, 5.9    4.5 years of age). Associations of histology, @entity1276 and @entity3976 , and postoperative intracranial subdural collections with postoperative intraspinal subdural collections were assessed by the Fisher exact test or   (2) test. The association between preoperative @entity5 volume and postoperative intraspinal subdural collections was assessed by the Wilcoxon rank sum test. RESULTS: The overall incidence of postoperative intraspinal subdural collections was 37/243 (15.2%), greatest  <=7 days postoperatively (36%); 97% were seen 0-41 days postoperatively (12.9    11.0 days). They were T2 hyperintense and isointense to CSF on T1WI, homogeneously enhanced, and resolved on follow-up MR imaging (35/35). None were symptomatic. They were associated with intracranial subdural collections (P = .0011) and @entity3976 (P = .0228). CONCLUSIONS: Postoperative intraspinal subdural collections are infrequent and clinically silent, resolve spontaneously, and have a distinctive appearance. @entity3976 appears to be a predisposing factor. In this series, repeat MR imaging by 4 weeks documented improvement or resolution of these collections in 88%.
