Natural History of Bone Formation Following Venous Sinus Stenting.

Background
Venous sinus stenting has emerged as a potential effective treatment for pulsatile tinnitus (PT) and idiopathic intracranial hypertension (IIH) secondary to venous sinus stenosis. Bone formation adjacent to the stent has been described in isolated case reports, but it has remained underexplored. This study aimed to characterize bone formation following venous sinus stenting.Methods
This retrospective observational study included consecutive patients who underwent venous sinus stenting for PT and/or IIH. Bone formation was assessed at each follow-up time point. Comparisons between patients with and without bone formation were performed using Mann-Whitney U test for continuous variables and Fisher's exact test for categorical variables. Univariate logistic regression was used to identify predictors of bone formation.Results
Twenty-one patients were included. Bone formation was observed in 12 (57%) patients at 3 months and 14 (67%) patients at 12 months. Patients with bone formation had a significantly greater maximum incomplete stent apposition compared to those without (median 1.9 mm [IQR: 1.4-3.0] vs. 0.9 mm [IQR: 0.6-1.5]; p=0.03). On logistic regression, each millimeter increase in maximum incomplete stent apposition was associated with 3.72-fold higher odds of bone formation (95% CI: 0.95-14.50; p=0.06). Symptom resolution at 12 months was similar between patients with and without bone formation (71% vs. 86%; p=0.62).Conclusions
Bone formation following venous sinus stenting is common, affecting two-thirds of patients at 12 months, was not associated with worse symptom resolution at 12 months, although longer follow-up is needed to characterize its long-term significance. Incomplete stent apposition could be associated with increased bone formation; however, this warrants confirmation in larger cohorts.