原发性三叉神经痛的伽玛刀双靶点治疗

目的 探索使用双靶点来改进伽玛刀治疗三叉神经痛的技术，提高有效率，减少复发率。方法 55例病人接受了伽玛刀双靶点治疗，9例失随访。87％的病人术前有手术史。一个靶点放在三叉神经根近桥脑处，另一个放在近半月神经节处，中心剂量84～90Gy，周边剂量42～45Gy，桥脑临界剂量20Gy。结果 随访4～72个月(平均30个月)。术后疼痛消失时间为2h～16个月(平均4个月)。按疼痛缓解评分，在随访时点，总有效率为95．7％，面部感觉异常等并发症的发生率为10．8％。经统计学分析，某些因素与疗效相关。结论 采用伽玛刀双靶点治疗三叉神经痛，因增加了辐射容量，比单靶点的成功率高、复发率低，并发症发生率与双靶点相近。特别值得一提的是，当病人术前有沿三叉神经注射史的，双靶点治疗比单靶点治疗的优越性更明显。

The treatment of trigeminal neuralgia using Gamma knife with double targets

Objective The purpose of this study was to assess the efficacy of Gamma knife surgery with two targets in the treatment of trigeminal neuralgia, and whether it can decrease pain recurrence. Methods 55 patients underwent Gamma knife surgery with double targets, 9 patients were lost of follow-up. 87% of the patients experienced other surgical intervention before radiosurgery. One target was set on root entry zone, the other was set on cisternal retrogasserian part of trigeminal nerve near by the Gasserian ganglion. The maximum dose of irradiation is 84~90 Gy, the marginal dose is 42~45 Gy corresponded to the isodose curve of 50% which must cover the pathway of trigeminal nerve in the cistern of cerebellar pons angle. The critical dose to pons was decided below 20 Gy. Results According to the pain response score, the complete and partial pain relief reached 95.7% of the patients treated and excellent result was reached in 80.4% who no longer needed medication. On the other hand, the statistic analysis revealed that some factors are related to the effectiveness using Gamma knife with double targets. Conclusions The results became all the better(the higher success rate , lower rate of pain recurrence and acceptable incidence of complication compared with single target technique). It is noticeable that the patients who experienced injection along the pathway of trigeminal nerve will have very good response to Gamma knife surgery with double targets rather than single target.