BACKGROUND Stereotactic radiosurgery (SRS) is an effective treatment for trigeminal neuralgia (TN). Nevertheless, a proportion of patients will experience recurrence and treatment-related sensory disturbances. In order to evaluate the predictors of efficacy and safety of image-guided non-isocentric radiosurgery, we analyzed the impact of trigeminal nerve volume and the nerve dose/volume relationship, together with relevant clinical characteristics. METHODS Two-hundred and ninety-six procedures were performed on 262 patients at three centers. In 17 patients the TN was secondary to multiple sclerosis (MS). Trigeminal pain and sensory disturbances were classified according to the Barrow Neurological Institute (BNI) scale. Pain-free-intervals were investigated using Kaplan Meier analyses. Univariate and multivariate Cox regression analyses were performed to identify predictors. RESULTS The median follow-up period was 38 months, median maximal dose 72.4 Gy, median target nerve volume 25 mm3, and median prescription dose 60 Gy. Pain control rate (BNI I-III) at 6, 12, 24, 36, 48, and 60 months were 96.8, 90.9, 84.2, 81.4, 74.2, and 71.2%, respectively. Overall, 18% of patients developed sensory disturbances. Patients with volume ≥ 30 mm3 were more likely to maintain pain relief (p = 0.031), and low integral dose (< 1.4 mJ) tended to be associated with more pain recurrence than intermediate (1.4-2.7 mJ) or high integral dose (> 2.7 mJ; low vs. intermediate: log-rank test, χ2 = 5.02, p = 0.019; low vs. high: log-rank test, χ2 = 6.026, p = 0.014). MS, integral dose, and mean dose were the factors associated with pain recurrence, while re-irradiation and MS were predictors for sensory disturbance in the multivariate analysis. CONCLUSIONS The dose to nerve volume ratio is predictive of pain recurrence in TN, and re-irradiation has a major impact on the development of sensory disturbances after non-isocentric SRS. Interestingly, the integral dose may differ significantly in treatments using apparently similar dose and volume constraints.

中文翻译：

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影响三叉神经痛的无框架非等距立体定向放射外科手术结局的因素：一项多中心队列研究。

背景技术立体定向放射外科手术（SRS）是三叉神经痛（TN）的有效治疗方法。尽管如此，仍有一部分患者会出现复发和与治疗相关的感觉障碍。为了评估影像引导的非等中心放射外科手术的疗效和安全性的预测指标，我们分析了三叉神经体积和神经剂量/体积关系的影响以及相关的临床特征。方法对3个中心的262例患者进行了296例手术。在17例患者中，TN继发于多发性硬化症（MS）。根据巴罗神经病学研究所（BNI）量表对三叉神经痛和感觉障碍进行分类。使用Kaplan Meier分析研究无痛间隔。进行单因素和多因素Cox回归分析以识别预测因素。结果中位随访期为38个月，中位最大剂量为72.4 Gy，中位目标神经体积为25 mm3，中位处方剂量为60 Gy。在6、12、24、36、48和60个月时的疼痛控制率（BNI I-III）分别为96.8％，90.9％，84.2、81.4、74.2和71.2％。总体而言，18％的患者出现了感觉障碍。体积≥30 mm3的患者更有可能维持疼痛缓解（p = 0.031），低积分剂量（<1.4 mJ）往往比中级（1.4-2.7 mJ）或高积分剂量（> 2.7 mJ;低vs.中：对数秩检验，χ2= 5.02，p = 0.019;低vs.高：对数对秩检验，χ2= 6.026，p = 0.014）MS，积分剂量和平均剂量是与疼痛复发相关的因素，在多变量分析中，再照射和MS是感觉障碍的预测指标。结论剂量与神经体积的比值可预测TN疼痛的复发，并且重新辐照对非等中心SRS后感觉障碍的发展有重大影响。有趣的是，在使用明显相似的剂量和体积约束的治疗中，积分剂量可能会显着不同。