Sigmoid plate dehiscence regrowth following transverse sinus stenting for pulsatile tinnitus

Background Sigmoid plate dehiscence (SPD) is a common finding in patients with pulsatile tinnitus (PT). The etiopathogenesis of SPD is controversial; however, increasing evidence suggests that SPD may be due to hemodynamic changes caused by upstream transverse sinus stenosis (TSS). Objective We sought to assess the evolution of SPD following transvenous endovascular treatment in patients with PT and SPD. Materials and methods We conducted a single-center retrospective cohort study of consecutive patients who underwent transvenous endovascular treatment for PT. Dehiscence was defined as the absence of a normal sigmoid plate overlying the sigmoid sinus, with direct contact of the sinus wall with the mastoid air cells. Regrowth was categorized via consensus by two neuroradiologists, based on the evaluation of the pre- and post-treatment CT images. Results Between September 2020 and March 2024, 15 patients met the inclusion criteria. All patients were female and the median age was 42 years (IQR 34.0–47.0). Bilateral SPD was present in 53.3% (8/15). TSS was present in all patients. Bone regrowth of the sigmoid plate was noted in 86.7% (13/15) of patients and occurred most often ipsilateral to the site of endovascular treatment (12/13, 92.3%). There were no significant differences in clinical, radiographic, or procedural characteristics between patients who experienced regrowth and those who did not. Conclusion Regrowth of sigmoid plate bone was observed in the majority of patients following endovascular treatment of PT. SPD is probably an acquired lesion, and its presence may not necessitate open surgical repair.