Risk of lingual nerve injuries in removal of mandibular third molars: a retrospective case-control study

Itaru Tojyo,Takashi Nakanishi,Yukihiro Hiraishi,Yukari Shintani,Shigeyuki Fujita,Kenjiro Okamoto

doi:10.1186/s40902-019-0222-4

Abstract

BackgroundThrough the analysis of clinical data, we attempted to investigate the etiology and determine the risk of severe iatrogenic lingual nerve injuries in the removal of the mandibular third molar.MethodsA retrospective chart review was performed for patients who had undergone microsurgical repair of lingual nerve injuries. The following data were collected and analyzed: patient sex, age, nerve injury side, type of impaction (Winter’s classification, Pell and Gregory’s classification). Ratios for the respective lingual nerve injury group data were compared with the ratios of the respective data for the control group, which consisted of data collected from the literature. The data for the control group included previous patients that encountered various complications during the removal of the mandibular third molar.ResultsThe lingual nerve injury group consisted of 24 males and 58 females. The rate of female patients with iatrogenic lingual nerve injuries was significantly higher than the control groups. Ages ranged from 15 to 67 years, with a mean age of 36.5 years old. Lingual nerve injury was significantly higher in the patient versus the control groups in age. The lingual nerve injury was on the right side in 46 and on the left side in 36 patients. There was no significant difference for the injury side. The distoangular and horizontal ratios were the highest in our lingual nerve injury group. The distoangular impaction rate in our lingual nerve injury group was significantly higher than the rate for the control groups.ConclusionDistoangular impaction of the mandibular third molar in female patients in their 30s, 40s, and 50s may be a higher risk factor of severe lingual nerve injury in the removal of mandibular third molars.

Highlights

Through the analysis of clinical data, we attempted to investigate the etiology and determine the risk of severe iatrogenic lingual nerve injuries in the removal of the mandibular third molar
The ratio for the female patients with iatrogenic lingual nerve injuries was significantly higher than the ratios found for the female patients in the various control groups (Table 1)
The side of the lingual nerve injury was located on the right in 44 and on the left in 35 patients

Summary

Introduction

Through the analysis of clinical data, we attempted to investigate the etiology and determine the risk of severe iatrogenic lingual nerve injuries in the removal of the mandibular third molar. The most common cause of lingual nerve injury is the removal of the mandibular third molars. The mean horizontal and Lingual nerve injury is an uncommon but important complication in the removal of the mandibular third molar. Renton et al reported that the incidence of lingual nerve injury was estimated to vary from 0.02 to 2% of the patients undergoing third molar surgery [2]. Pippi et al reviewed the incidence of temporary lingual nerve injury and estimated it to vary from 0 to 37.5% of the patients undergoing third molar surgery, while the incidence of permanent lingual nerve surgery was estimated

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Discussion

Conclusion