Trochlear nerve palsy associated with intracranial aneurysms: Scoping review

Background: Trochlear nerve palsy (TNP) in patients with ruptured or unruptured intracranial aneurysms (IA) can result from the disease process or its treatment. We systematically reviewed the literature on TNP in patients with IA. Methods: PubMed, ScienceDirect, and Web of Science were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data extraction and quality assessment were performed according to pre-established guidelines. Results: Our review yielded 29 studies out of 273 retrieved articles. A total of 134 patients with TNP and IA were included in our study. The mean age was 55.35 years and females accounted for 78%. Among the TNP cases, 91% harbored aneurysms located in the internal carotid artery and posterior communicating artery, and 93% of these aneurysms were large to giant-sized aneurysms. Out of the total cases, the vast majority (96.2%) exhibited TNP at the time of their initial presentation. Only a small proportion ( n = 5, 3.73%) developed TNP after the treatment of their aneurysms. For the multiplicity of cranial nerve involvement, 81 (60.4%) had cranial nerve palsies other than trochlear palsy, and the remaining 53 (39.5%) had isolated TNP. Finally, in terms of TNP outcome, the recovery rate from TNP was identified in 110 cases (85.2%), with a duration of resolution of <6 months ( n = 58, 89.2%). Conclusion: TNPs are correlated with IAs, and this correlation depends on the location and size of the aneurysms.