Meyer's loop and its anatomical importance in surgical planning - a systematic review

Abstract

Background: Meyer's loop (ML), the anterior extension of the optic radiation, is critical in neurosurgical planning for temporal lobe procedures. Establishment of accurate localization of ML relative to key anatomical landmarks is crucial to minimize post-surgical visual field deficits.

Materials and methods: A systematic review was conducted using PubMed, Scopus, and Embase databases from September to December 2024, following PRISMA 2020 guidelines. Anatomical and radiological studies focused on distances from Meyer's loop to surgical landmarks were included.

Results: Out of 1,466 identified studies, 27 met the inclusion criteria (21 radiological and 6 anatomical). 26 of included articles presented measurements of ML-TP distance which ranged from 14.0 to 54.4 mm. Asymmetry of the ML was observed in approximately half of the cases.

Conclusions: This review highlights the variability in ML positioning. Thorough individualized surgical planning with properly selected imaging protocol might reduce the risk of postoperative visual field deficits.

Keywords: Meyer’s loop; anterior temporal lobe resection; optic radiation; selective amygdalohippocampectomy; temporal lobe epilepsy.