Letter regarding article 'Focal stenosis of the sigmoid sinus causing intracranial venous hypertension: Case report, endovascular management and review of the literature'.

Abstract

To the Editor: I read with great interest the article by Honarmand et al. in which they nicely review the latest arguments about the pathophysiology of idiopathic intracranial hypertension (IIH) on the basis of their case. They report a dramatic efficiency of endovascular stent placement and angioplasty of stenotic sigmoid sinus in a 31-month-old boy presenting with IIH symptoms. They refer to the hypothesis of De Simon et al. that explains the model of cerebrospinal fluid (CSF) pressure and sinus collapsibility, as well as the different venous-CSF pressure balance values as a result. I greatly appreciate the Honarmand et al. detailed review about the pathogenesis of IIH and I would like to state that this report gives very comprehensive and useful knowledge about this issue; however, I would like to comment on the article in some aspects. First, I agree with the clearness of the well-known association of IIH with sinus stenosis in the literature; whereas, as they stated, it is still not clear whether stenosis of the sinuses is a cause or a consequence of IIH. Nonetheless, they refer the review of Dykhuizen et al. and remark on the utilisability of endovascular stent placement in both patient groups, with IIH involving the patients of secondary sinus stenosis and stenosis as the consequence of intracranial hypertension (ICH). As an accurate differentiation of these two underlying mechanisms is still not available, we cannot know which processes had been improved by the endovascular treatment method in this referenced review. Although there are a large number of patients reported to respond to endovascular treatments in the literature, several cases have also been reported to fail with stent therapy; hence, the question of which patient will benefit from the endovascular process or CSF diversion methods remains unclear. On the other hand, in our unique report, we demonstrated multiple times (4 times) the relapse of transverse sinus stenosis and recovery of stenosis after lumbar punctures in a medically resistant patient with IIH. Every time, the clinical course was correlated with magnetic resonance venography (MRV) findings and finally, lumboperitoneal shunt has ensured the permanent recovery still, on the third year of follow up. Via our case, I would like to add that a significant recovery of sinus stenosis after lumbar punctures, which can be easily shown by follow-up MRVs, may give very crucial points in a decision selecting between the treatment of LPS or endovascular methods. Finally, as Honarmand et al. stated that the case in their report can rather be evaluated as hydrocephalus secondary to sinus stenosis: While the mechanisms of hydrocephalus and IIH are different, to give comments about IIH based on this patient could lead to confusing results.