BACKGROUND The suprameatal tubercle (SMT) may obscure the neurovascular compression (NVC) in microvascular decompression (MVD) for trigeminal neuralgia (TGN). The aim of this study is to address the necessity of resecting SMT in MVD for TGN. METHODS We retrospectively analyzed radiological findings of 461 MVDs in patients with TGN, focusing on the relation between SMT and the NVC site. Three-dimensional (3D) images were used for preoperative evaluation. The NVC sites were obscured by SMT in 48 patients (10.4%) via the retrosigmoid approach. This study was conducted to review the management of SMT among these patients. Resection of SMT was performed in 8 patients (resected group) for direct visualization of the NVC site. On the other hand, nerve decompression was achieved without resecting SMT for the rest of the 40 patients (non-resected group). Biographical data, radiological findings, intraoperative findings, and surgical outcomes were retrospectively evaluated. RESULTS The mean height of SMT obscuring NVC was 5.0 mm (2.8-13.9 mm) above the petrous surface. The NVC was located at a mean of 1.9 mm (0-5.9 mm) from the porous trigeminus. The most common offending vessel was the superior cerebellar artery (SCA, 56.3%), followed by the transverse pontine vein (TPV, 29.2%). In the resected group, the transposing culprit vessels were feasibly performed after direct visualization of the NVC site, whereas in the non-resected group, the SCA was successfully transposed using curved instruments after thorough dissection around the nerve. TPV having contact with the nerve was coagulated and divided. Immediate pain relief was obtained in all patients except one who experienced delayed pain relief 1 month after surgery. Facial numbness at discharge was noted in 9 patients (18.8%); thereafter, numbness diminished over time. Numbness at the final visit was observed in 5 patients (10.4%) at mean of 49 months after MVD. Recurrent pain occurred in 4 patients (8.3%) in total. Statistical analysis showed no significant differences in surgical outcomes between both groups. CONCLUSIONS Direct visualization of the NVC site by resecting the SMT does not affect surgical outcomes in the immediate and long term. Resecting the SMT is not always necessary to accomplish nerve decompression in most cases by use of suitable instruments and techniques.

中文翻译：

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三叉神经痛微血管减压术中上睑结节的切除术。

背景技术对于三叉神经痛（TGN），上睑结节（SMT）可能会掩盖微血管减压（MVD）中的神经血管压迫（NVC）。这项研究的目的是解决在TGN的MVD中切除SMT的必要性。方法我们回顾性分析了TGN患者中461例MVD的影像学表现，重点是SMT与NVC部位之间的关系。三维（3D）图像用于术前评估。通过乙状结肠后入路，SMT使NVC部位模糊不清，占48例（10.4％）。进行这项研究以回顾这些患者中SMT的管理。在8例患者（切除组）中进行了SMT切除，以直接可视化NVC部位。另一方面，其余40例患者（未切除组）在不切除SMT的情况下实现了神经减压。回顾性评估传记资料，放射学发现，术中发现和手术结果。结果SMT遮盖NVC的平均高度为岩壁上方5.0毫米（2.8-13.9毫米）。NVC位于距多孔三叉骨平均1.9毫米（0-5.9毫米）的位置。最常见的血管是小脑上动脉（SCA，56.3％），其次是桥脑横静脉（TPV，29.2％）。在切除组中，在直接可视化NVC部位后可行地进行了移位的罪犯血管，而在未切除组中，在彻底解剖神经周围后，使用弯曲器械成功地置换了SCA。与神经接触的TPV被凝结并分裂。所有患者均获得了立即的疼痛缓解，除了一名患者在手术后1个月延迟缓解疼痛。出院时面部麻木9例（18.8％）；此后，麻木感随着时间的流逝而减少。MVD后平均49个月，有5位患者（10.4％）在最后一次就诊时出现麻木。共有4例患者（8.3％）发生复发性疼痛。统计学分析显示两组之间的手术结果无显着差异。结论通过切除SMT直接可视化NVC部位在近期和长期内均不影响手术效果。在大多数情况下，通过使用合适的工具和技术，切除SMT并非总是必要的以实现神经减压。麻木感随着时间的流逝而减少。MVD后平均49个月，有5位患者（10.4％）在最后一次就诊时出现麻木。共有4例患者（8.3％）发生复发性疼痛。统计学分析显示两组之间的手术结果无显着差异。结论通过切除SMT直接可视化NVC部位在近期和长期内均不影响手术效果。在大多数情况下，通过使用合适的工具和技术，切除SMT并非总是必要的以实现神经减压。麻木感随着时间的流逝而减少。MVD后平均49个月，有5位患者（10.4％）在最后一次就诊时出现麻木。共有4例患者（8.3％）发生复发性疼痛。统计学分析显示两组之间的手术结果无显着差异。结论通过切除SMT直接可视化NVC部位在近期和长期内均不影响手术效果。在大多数情况下，通过使用合适的工具和技术，切除SMT并非总是必要的以实现神经减压。结论通过切除SMT直接可视化NVC部位在近期和长期内均不影响手术效果。在大多数情况下，通过使用合适的工具和技术，切除SMT并非总是必要的以实现神经减压。结论通过切除SMT直接可视化NVC部位在近期和长期内均不影响手术效果。在大多数情况下，通过使用合适的工具和技术，切除SMT并非总是必要的以实现神经减压。