Department of Anatomy and Histology, University of Sydney, Sydney, New South Wales, Australia.
J Pain. 2013 Aug;14(8):865-72. doi: 10.1016/j.jpain.2013.02.014. Epub 2013 May 17.
Trigeminal neuralgia, painful trigeminal neuropathy, and painful temporomandibular disorders (TMDs) are chronic orofacial pain conditions that are thought to have fundamentally different etiologies. Trigeminal neuralgia and neuropathy are thought to arise from damage to or pressure on the trigeminal nerve, whereas TMD results primarily from peripheral nociceptor activation. This study sought to assess the volume and microstructure of the trigeminal nerve in these 3 conditions. In 9 neuralgia, 18 neuropathy, 20 TMD, and 26 healthy controls, the trigeminal root entry zone was selected on high-resolution T1-weighted magnetic resonance images and the volume (mm(3)) calculated. Additionally, using diffusion-tensor images (DTIs), the mean diffusivity and fractional anisotropy values of the trigeminal nerve root were calculated. Trigeminal neuralgia patients displayed a significant (47%) decrease in nerve volume but no change in DTI values. Conversely, trigeminal neuropathy subjects displayed a significant (40%) increase in nerve volume but again no change in DTI values. In contrast, TMD subjects displayed no change in volume or DTI values. The data suggest that the changes occurring within the trigeminal nerve are not uniform in all orofacial pain conditions. These structural and volume changes may have implications in diagnosis and management of different forms of chronic orofacial pain.
This study reveals that neuropathic orofacial pain conditions are associated with changes in trigeminal nerve volume, whereas non-neuropathic orofacial pain is not associated with any change in nerve volume.
三叉神经痛、痛性三叉神经病变和痛性颞下颌关节紊乱（TMD）是慢性的面痛疾病，据认为它们具有根本不同的病因。三叉神经痛和神经病变被认为是由三叉神经的损伤或受压引起的，而 TMD 主要是由于周围伤害感受器的激活。本研究旨在评估这三种情况下三叉神经的体积和微观结构。在 9 例神经痛、18 例神经病变、20 例 TMD 和 26 例健康对照中，在高分辨率 T1 加权磁共振图像上选择三叉神经根进入区，并计算体积（mm(3)）。此外，使用弥散张量图像（DTI），计算三叉神经根的平均弥散度和各向异性分数值。三叉神经痛患者的神经体积显著减少（47%），但 DTI 值没有变化。相反，三叉神经病变患者的神经体积显著增加（40%），但 DTI 值仍无变化。相比之下，TMD 患者的体积或 DTI 值没有变化。这些数据表明，在所有口腔面痛疾病中，三叉神经内发生的变化并不统一。这些结构和体积的变化可能对不同形式的慢性口腔面痛的诊断和治疗有影响。
本研究表明，神经病变性面痛疾病与三叉神经体积变化有关，而非神经病变性面痛则与神经体积变化无关。
