Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia, USA.
J Neurosurg. 2010 Jul;113(1):53-8. doi: 10.3171/2009.9.jns09196.
Trigeminal neuralgia is believed to be related to vascular compression of the affected nerve. Radiosurgery has been shown to be reasonably effective for treatment of medically refractory trigeminal neuralgia. This study explores the rate of occurrence of MR imaging-demonstrated vascular impingement of the affected nerve and the extent to which vascular impingement affects pain relief in a population of trigeminal neuralgia patients undergoing Gamma Knife radiosurgery (GKRS).
The authors performed a retrospective analysis of 106 cases involving patients treated for typical trigeminal neuralgia using GKRS. Patients with or without single-vessel impingement on CISS MR imaging sequences and with no previous surgery were included in the study. Pain relief was assessed according to the Barrow Neurological Institute (BNI) pain intensity score at the last follow-up. Degree of impingement, nerve diameter preand post-impingement, isocenter placement, and dose to the point of maximum impingement were evaluated in relation to the improvement of BNI score.
The overall median follow-up period was 31 months. Overall, a BNI pain score of 1 was achieved in 59.4% of patients at last follow-up. Vessel impingement was seen in 63 patients (59%). There was no significant difference in pain relief between those with and without vascular impingement following GKRS (p > 0.05). In those with vascular impingement on MR imaging, the median fraction of vessel impingement was 0.3 (range 0.04-0.59). The median dose to the site of maximum impingement was 42 Gy (range 2.9-79 Gy). Increased dose (p = 0.019) and closer proximity of the isocenter to the site of maximum vessel impingement (p = 0.012) correlated in a statistically significant fashion with improved BNI scores in those demonstrating vascular impingement on the GKRS planning MR imaging.
Vascular impingement of the affected nerve was seen in the majority of patients with trigeminal neuralgia. Overall pain relief following GKRS was comparable in those with and without evidence of vascular compression on MR imaging. In subgroup analysis of those with MR imaging evidence of vessel impingement of the affected trigeminal nerve, pain relief correlated with a higher dose to the point of contact between the impinging vessel and the trigeminal nerve. Such a finding may point to vascular changes affording at least some degree of relief following GKRS for trigeminal neuralgia.
据信三叉神经痛与受影响神经的血管压迫有关。放射外科治疗已被证明对治疗药物难治性三叉神经痛是合理有效的。本研究探讨了在接受伽玛刀放射外科治疗（GKRS）的三叉神经痛患者中，磁共振成像（MRI）显示受影响神经血管受压的发生率，以及血管受压对疼痛缓解的影响程度。
作者对 106 例采用 GKRS 治疗的典型三叉神经痛患者进行了回顾性分析。纳入研究的患者为 CISS MR 成像序列上存在单血管压迫或无既往手术史的患者。根据最后一次随访时的巴罗神经研究所（BNI）疼痛强度评分评估疼痛缓解情况。评估压迫程度、压迫前后神经直径、等中心点位置和最大压迫点剂量与 BNI 评分改善的关系。
总体中位随访时间为 31 个月。总体而言，最后一次随访时，59.4%的患者达到 BNI 疼痛评分 1 分。63 例（59%）患者存在血管压迫。GKRS 治疗后，有血管压迫和无血管压迫的患者疼痛缓解无显著差异（p＞0.05）。在 MRI 上有血管压迫的患者中，血管压迫的中位数分数为 0.3（范围 0.04-0.59）。最大压迫点的中位数剂量为 42Gy（范围 2.9-79Gy）。在那些在 GKRS 计划 MRI 上显示血管压迫的患者中，剂量增加（p=0.019）和等中心点更接近最大血管压迫部位（p=0.012）与 BNI 评分的改善呈统计学显著相关。
大多数三叉神经痛患者存在受影响神经的血管压迫。在 MRI 上有或无血管压迫证据的患者中，GKRS 治疗后的总体疼痛缓解情况相当。在那些有 MRI 证据显示受影响的三叉神经血管受压的亚组分析中，疼痛缓解与受压迫血管与三叉神经接触点的更高剂量相关。这一发现可能表明血管变化至少在某种程度上为三叉神经痛的 GKRS 治疗提供了缓解。
