[Evaluating the risk factors of inferior alveolar nerve injury following removal of the mandibular third molars].

抄録

To evaluate the risk factors of inferior alveolar nerve injury (IANI) after surgical removal of the mandibular third molars (M3) and present a new risk scoring system to predict the probability of IANI. Patients who underwent extraction of M3 in the Stomatology Hospital, Zhejiang University School of Medicine from April 2017 to December 2019 were involved. The investigators enrolled a sample composed of 949 mandibular third molars. Prediction model was used for univariate and multivariate analysis of gender, age, M3, inferior alveolar canal (IAC), and the contact between M3 and IAC, to assess the risk factors of IANI. Combined with the risk factors determined by the outcomes of prediction model, the risk scoring system was constructed. The diagnostic performance of each cut-off score was examined to conduct a risk stratification of IANI risk scores. The predictive ability and reliability of the model were evaluated. In prediction model, twenty nine cases (4.4%, 29/664) experienced postoperative IANI. Number of root (<0.01), depth of impaction (<0.05), contact between M3 and IAC (<0.01) and their contact position (<0.05) were statistically significant as contributing risk factors of IANI. Specifically, the incidence of temporary IANI was higher in those who aged under 25 years (<0.001), while female suffer more permanent injury (<0.05). Based on the IANI risk scoring system, patients were stratified into low-risk, middle-risk and high-risk groups at cutoff scores of 3 and 4. The area under the receiver operator characteristic curve of the risk scoring system were 0.81 [95% (0.70-0.90), =0.002] and 0.80 [95% (0.68-0.92), =0.007] towards good discrimination. Age, gender, number of root, depth of impaction, and contact between M3 and IAC were risk factors of IANI. IANI risk scoring system might help in preoperative assessment, recognition of high-risk cases and decision-making to reduce IANI.

探究下颌第三磨牙拔除相关的下牙槽神经损伤（inferior alveolar nerve injury，IANI）危险因素，并构建IANI风险评分系统用于术前IANI风险评估，为临床提供参考。 本研究纳入2017年4月至2019年12月于浙江大学医学院附属口腔医院口腔颌面外科接受牙拔除术的949颗下颌第三磨牙，其中，664颗为预测样本，285颗为验证样本。通过对预测样本的性别、年龄、下颌第三磨牙、下牙槽神经管（inferior alveolar canal，IAC）及下颌第三磨牙与IAC的接触关系进行单因素与多因素分析，确定IANI危险因素并构建IANI风险评分系统。根据不同截止分值的诊断参数评估结果，对IANI风险分层，并进行预测模型验证。 预测样本中，4.4%（29/664）术后出现IANI。下颌第三磨牙牙根数目（<0.01）、阻生深度（<0.05）以及牙根与IAC的接触关系（<0.01）与垂直接触位置（<0.05）是IANI的危险因素；年龄<25岁是暂时性IANI的危险因素（<0.001），性别为女性是永久性IANI的危险因素（<0.05）。IANI风险根据评分划分为低风险（≤2分）、中风险（3分）和高风险组（≥4分且≤6分）。IANI风险评分系统模型区分度较好，暂时性IANI评分曲线下面积为0.81［95%（0.70~0.90），=0.002］，永久性IANI评分曲线下面积为0.80［95%（0.68~0.92），=0.007］。 患者年龄、性别、下颌第三磨牙牙根数目、阻生深度、牙根与IAC的接触关系与垂直接触位置是术后IANI的危险因素。IANI风险评分系统有助于临床医师术前筛选与识别高风险病例。.