Can magnetic resonance imaging (MRI) reduce lingual nerve injuries during mandibular third molar surgery? A scoping review.

Background: Recent advancements in MRI, with its superior soft tissue resolution and ionising radiation-free nature, provide a promising solution for the limitations of current imaging modalities. This review aims to evaluate whether MRI can be utilised to reduce the risk of lingual nerve (LN) injury during mandibular third molar surgery (M3M).

Methods: Following PRISMA guidelines, the protocol was registered in PROSPERO (CRD42024625994). A systematic literature search was employed across MEDLINE/PubMed, Scopus, Web of Science, Cochrane Library, and Science Direct without language or date restrictions. Studies assessing MRI's ability to visualise the LN and surgically relevant anatomy were included. The risk of bias was evaluated using ROBINS-I. Given the heterogeneity of included studies, this review was conducted as a scoping review to explore the range of evidence available, and findings were summarised through narrative synthesis.

Results: Fourteen studies met the inclusion criteria. While none directly assessed whether MRI reduces the incidence of LN injury, it consistently demonstrated superior LN visualisation compared to conventional imaging. Among the sequences evaluated, Three-dimensional Double-Echo Steady-State with Water Excitation (3D-DESS-WE) and Sampling Perfection with Application-optimised Contrasts using different flip angle Evolutions with Short Tau Inversion Recovery (SPACE-STIR) provided nerve delineation and anatomical clarity. However, variability in scan duration, availability of MRI, the need for specialised image interpretation, and only moderate inter-observer agreement currently limit the clinical application of MRI in M3M surgery.

Conclusion: Definitive evidence of the efficacy of MRI in reducing nerve injury during M3M is lacking. However, moderate to low quality evidence suggests that MRI offers superior visualisation of the LN compared to conventional imaging. Further clinical trials are needed to evaluate whether MRI's enhanced preoperative visualisation translates into improved clinical outcomes from M3M surgery.