Objective Suprameatal tubercle (SMT), a bony prominence located above the internal acoustic meatus, is reported to impede the microscopic view during microvascular decompression (MVD) for trigeminal neuralgia (TN). For an enlarged SMT, removal of the SMT may be required in addition to the routine MVD to precisely localize the offending vessels. The objective of this study is to investigate the predictive factors influencing the requirement of SMT removal during trigeminal MVD.

Methods We retrospectively reviewed 197 patients who underwent MVD for TN, and analyzed the correlation of the SMT height and other clinicosurgical data with the necessity to remove the SMT during MVD. The parameters evaluated in the statistical analyses included maximum SMT height, patient's clinical characteristics, surgical data including the type and number of offending vessels, and surgical outcomes.

Results SMT removal was required for 20 patients among a total of enrolled 197 patients. In the univariate analysis, maximum SMT height, patient's age, and number (≥ 2) of offending vessels were associated with the requirement for SMT removal. Multivariate analysis with binary logistic regression revealed that the maximum SMT height and number (≥ 2) of offending vessels were significant factors influencing the necessity for SMT removal. A receiver operating characteristic curve analysis revealed that an SMT height ≥ 4.8 mm was the optimal cutoff value for predicting the need for SMT removal.

Conclusion Large SMTs and the presence of multiple offending vessels are helpful in predicting the technical difficulty of trigeminal MVD associated with the necessity of SMT removal.

目的 甲上结节 (SMT) 是位于内耳道上方的骨突出，据报道在三叉神经痛 (TN) 的微血管减压 (MVD) 过程中会妨碍显微镜观察。对于扩大的 SMT，除了常规 MVD 之外，可能还需要去除 SMT，以精确定位有问题的血管。本研究的目的是调查影响三叉神经 MVD 期间 SMT 去除要求的预测因素。

方法 回顾性分析197例因TN而接受MVD的患者，分析SMT高度和其他临床手术数据与MVD期间是否需要切除SMT的相关性。统计分析中评估的参数包括最大 SMT 高度、患者的临床特征、手术数据（包括违规血管的类型和数量）以及手术结果。

结果 197 例患者中，有 20 例需要切除 SMT。在单变量分析中，最大 SMT 高度、患者年龄和违规血管数量 (≥ 2) 与移除 SMT 的要求相关。二元 Logistic 回归多变量分析显示，最大 SMT 高度和违规血管数量（≥ 2）是影响 SMT 去除必要性的重要因素。接受者操作特征曲线分析显示，SMT 高度≥ 4.8 mm 是预测是否需要去除 SMT 的最佳截止值。

结论 大型 SMT 和多个违规血管的存在有助于预测与 SMT 去除必要性相关的三叉神经 MVD 的技术难度。