Anatomical Risk Factors Associated with Inferior Alveolar Nerve Injury During Third Molar Surgery: A Systematic...

Understanding the impact of anatomical factors in mandibular third molar surgery is crucial for minimizing the risk of nerve damage and improving patient outcomes.

Prospective studies published in English language and based on anatomical risk factors associated with inferior alveolar nerve injury during lower third molar surgery were incorporated. A comprehensive online and manual search of English language literature with no date restrictions was done in November 2023. Of the 101 studies, only 9 were included for the qualitative analysis. The variables assessed were as follows: type of preoperative assessment, duration of follow-up, incidence of temporary or permanent paresthesia, and criteria used to identify the type of impaction, proximity to inferior alveolar nerve canal (IAC), and IAC shape.

Around 22.22% of the studies did a follow-up period of 2 years, radiographic techniques employed included intraoral periapical radiograph (IOPA), panoramic (PAN) radiographs, cone beam computed tomography (CBCT) and a combination of PAN and CBCT, IOPA and shift cone technique in 11% of the studies while in 22% of the studies radiographs type was unspecified; the type of impaction criteria was assessed in six studies using various criteria based on degree of impaction, Pell and Gregory classification and Ma'aita & Alwrikat classification; IAC shape evaluation was done in two studies; paresthesia incidence was observed in 89% of the studies and proximity of anatomical landmarks to the IAC was observed in all nine studies which employed different classifications based on Rood and Shehab, Maglione's, Felez-Guiterrez et al. and > 2 mm / < 2 mm theory. Additionally, studies have shown that the use of CBCT imaging can significantly improve the accuracy of preoperative risk assessment for inferior alveolar nerve injury.

Certain anatomical factors raise inferior alveolar nerve injury risk, but careful preoperative planning mitigates it while standardized assessments aid meta-analysis. Furthermore, the use of advanced imaging techniques like CBCT can enhance the precision of preoperative risk assessment, potentially leading to better surgical outcomes and reduced complications.