Clinicoradiological Evaluation of Trigeminal Neurovascular Loops: A Retrospective Cohort Study from Eastern India

Abstract

Introduction: Several lesions may affect trigeminal nerve from the nucleus to peripheral branches causing facial pain, called trigeminal Neuralgia (TN). Neurovascular compression (NVC) of the trigeminal nerve is the primary cause of TN, usually occurring at the root entry zone but is known to occur in both symptomatic and asymptomatic nerves. Aim: To evaluate trigeminal neurovascular loops (NVLs) clinico- radiologically and to know the association between the shortest distance of loop as well as the severity of compression with clinical symptoms. Materials and Methods: This is a Retrospective cohort study conducted in March 2020 after collecting data from January 2017 to January 2020 in a tertiary care center of Eastern India. All the patients, detected with trigeminal NVLs by Magnetic Resonance (MR) imaging were evaluated clinically (from records) & radiologically and an association is drawn between the distance of the loop, the severity of compression with symptoms. Data were analyzed using Statistical Package for Social Sciences (SPSS) statistical software version 24.0. Result: Among 103 cases studied, the symptomatic and asymptomatic loops were 76 & 27. In symptomatic group, males and females were 48 (63%) and 28 (36.8%) respectively with mean age of 56 years with male:female ratio in symptomatic group of 76 cases was 1.7:1. Left-sided presentation and pain in the maxillary area were found in 39 (51.3%) and 33 (43.4%) cases. Sharp/electric current like/ lancinating pain was present in 72 (94.7%) case. Triggering factors and spontaneous onset pain were presentations in 70 (92%) and 76 (100%) cases. Magnetic Resonance Imaging (MRI) showed NVLs with a just contact to the nerve in all asymptomatic (27/27,100%) and most symptomatic cases (57/76, 75%). The superior cerebellar artery was found to be the most common vessel involved (59/76, 77.6%). Proximal and bilateral NVLs were found in 62 (82.89%) and 27 (35.9%) cases of symptomatic nerves. Severe NVC was only present in symptomatic nerves in 19 (25%) cases. Conclusion: Typical clinical features of trigeminal neuralgia include male preponderance, lancinating pain on maxillary area of left face. Compression by NVLs are most common cause of TN, among which Superior cerebellar artery is most common culprit vessel. Severe neurovascular compressions are more symptomatic. All neurovascular compressions are not always symptomatic.