伽玛刀双靶点与单靶点治疗原发性三叉神经痛的对比分析

Comparative analysis of one and two target points of Gamma knife radiosurgery for trigeminal neuralgia

目的对比分析伽玛刀双靶点与单靶点治疗原发性三叉神经痛的疗效。方法回顾性分析236例单靶点与12例双靶点治疗的经验。均使用Leksell-B型伽玛刀,准直器4mm。双靶点者靶点分别置于三叉神经根脑桥进入区和近三叉神经半月节处,单靶点者仅置于三叉神经根脑桥进入区。两组均为中心剂量70～90Gy,50%等剂量线限定靶点;将20%等剂量线限定在脑桥表面,使脑干表面剂量小于16Gy。结果随访12～114个月,平均66.4月。单靶点组有效223例(94.5%),无效13例(5.5%),复发14例(5.9%),发生并发症9例(3.8%)。双靶点组有效12例(100%),发生并发症4例(33.3%)。经统计学分析,两组治疗有效率差异无统计学意义(P>0.05),并发症发生率以双靶点者为高(P<0.05)。结论双靶点治疗不能明显提高有效率,反而可使并发症发生率明显增加。当三叉神经根紧贴脑桥或受压变形时,为弥补单靶点可能引起的三叉神经受照不足,可使用双靶点治疗。

Objective To compare the therapeutic efficacy of Gamma Knife radiosurgery （GKRS） for primary trigeminal neuralgia using one and two target points. Methods All patients in our study were operated on via a Leksell Gamma knife B model unit, with the collimator of 4 mm. Twelve cases were treated using two target points, one located in the trigeminal root entry zone （REZ）, and the other was near the trigeminal ganglion; while the other 236 with one target point in the REZ. 20% isodose line was tangential to the brainstem surface. The prescription central dose varied from 70 to 90 Gy, and the isodose was 50% in the two groups. Results Follow-up ranged from 12 to 114 months （median, 66.4 months）, and the pain relief rate of single- and two-isocenter group were 94.5% （223 cases） and 100% （12 cases） respectively. Fourteen patients （5.9%） experienced pain recurrence 6 months after being completely free from pain. And the complication rate of the two target points group was 33.3% （4 cases）, which was higher than 3.8% （9 cases） of single group. Conclusion GKRS for trigeminal neuralgia using two target points does not significantly improve pain relief but may increase complications; it should be selected only if the root entry zone of the trigeminal nerve was compressed and distorted because of its tight contact with the pons.