Postoperative Cerebral Venous Sinus Thrombosis Following Retrosigmoid Craniotomy for a Cerebellopontine Angle Tumor: A Clinical and Radiological Analysis

Introduction: The retrosigmoid approach (RSA) is one of the most common approaches to the posterolateral skull base. Postoperative cerebral venous sinus thrombosis (CVST) is a rare but known complication following RSA. There is a paucity of literature regarding CVST. To overcome this lack, we performed radiological and clinical analyses to report our experience with CVST after RSA.

Methods: This study was a retrospective evaluation of radiological and clinical data of patients undergoing elective RSAs between 2016 and 2021. Radiological data encompassed routine contrast-enhanced computed tomography (CT) head scans, and clinical data incorporated medical charts. CVSTs were divided into demonstrating radiological features of CVSTs (rCVSTs) and clinical CVSTs (cCVSTs), in which a clinical diagnosis of CVST had been established during hospitalization. CT scans were evaluated for rCVST in sigmoid sinus (SS) and transverse sinus (TS)—each treated separately—on the ipsilateral side of the RSA. Identifying rCVST required visualization of lack of contrast in any of sinuses. We evaluated the closest distance from the edge of the craniotomy to either of the sinuses as a method of quantifying sinuses exposures: Positive value expresses closest distance between edge of the craniotomy and the sinus, whereas negative value represents overlapping of the craniotomy with the sinus and its magnitude. We analyzed independent group differences using Mann–Whitney U-test and Welch's unequal variances t-test; and chi-square test to examine if values of qualitative variables are related.

Results: We included 130 patients (52 males, 78 females) with a median age of 46.0. We recognized rCVSTs in 46.9% (61/130), most often in the TS (65.6%, 40/61). There were 4 cases of cCVSTs (3.1%, 4/130). Out of patients with rCVST, only 3 (4.9%, 3/61) had cCVST; the remaining patient had superior sagittal sinus thrombosis, but no rCVST in TS nor SS. Distances to the SS and TS were not statistically different in regard to presence of cCVST (p = 0.32 and p = 0.72). Distance to the SS was not significantly different in regard to rCVST (p = 0.13). Contrarily, lesser exposure of the TS correlated with lower incidence of rCVST (p = 0.009). A receiver operating characteristic curve analysis revealed that exposing the TS over 6.95 mm increases the risk of rCVST (sensitivity: 66.67%, specificity: 57.38%, area under curve: 0.634). When we analyzed rCVST in the SS only, its presence was related to the greater exposure of SS (p = 0.04). A similar analysis for the TS did not reveal significant difference (p = 0.209). Side of the sinus dominance was not related with cCVST nor rCVST. However, when the surgery was on the side of the dominant sinuses, the rCVST was more frequent (p = 0.042). Among other examined factors—intraoperative injuries of the sinuses, intraoperative difficulties and tumor volume—none was related with rCVST nor cCVST (p = 0.321 and p = 0.655, p = 0.241 and p = 0.729, p = 0.203 and p = 0.493, respectively).

Conclusions: rCVST is a common consequence of RSA, but it rarely (4.9%, 3/61) becomes symptomatic. Surgery on the side of the dominant sinuses and magnitude of exposing them seem to be related with rCVST. Further prospective studies are needed.

Publikationsverlauf

Artikel online veröffentlicht:
01. Februar 2023