伽玛刀治疗听神经瘤致神经损伤的临床随访分析

目的 探讨伽玛刀治疗听神经瘤致听神经和面神经及三叉神经损伤情况。方法 收集1997～2000年采用伽玛刀治疗并获得随访的听神经瘤患者43例,共46个听神经瘤。随访时间为6～24个月,平均16．9个月。肿瘤周边剂量12—15 Gy。肿瘤平均直径28mm、10-20mm12个,21～30mm23个,31mm以上11个。结果 肿瘤总控制率91．3％。治疗前听力正常患者有用听力保留率治疗后为100％,6个月87％,2年78％,小肿瘤的听力保留高于大肿瘤。面神经和三叉神经放射损伤在治疗后0．5年出现。治疗后0．5年、1年和2年面神经损害的发生率分别为15．3％、7．6％和3．8％。三叉神经损害的发生率分别为11．4％、3．8％和3．8％。30mm以内肿瘤面神经和三叉神经放射损伤均为3．8%;30mm以上肿瘤面神经和三叉神经放射损伤分别为11．5％和7．6％,治疗后2年均为3．8％。20mm以内肿瘤听力保留在治疗前水平的为100%。结论 伽玛刀治疗听神经瘤用12．15Gy的周边剂量对控制听神经瘤是有用的,对患者的有用听力保留有重要意义。听神经瘤伽玛刀治疗后发生的临近神经损伤是亚致死性且能逐渐恢复。伽玛刀治疗具有较高的有用听力保护率和相对低的面神经和三叉神经损伤率。

Neuropathy in nearby cranial nerves after acoustic schwannoma gamma knife radiosurgery,a follow-up study

OBJECTIVE: To investigate the risks of facial, trigeminal and acoustic neuropathies after acoustic schwannoma gamma knife radiosurgery. METHODS: The clinical data of forty-three patients with 46 masses of acoustic schwannoma who underwent gamma knife radiosurgery with the dose of 12 approximately 15 Gy to the tumor margin between January 1997 and October 2000 and were followed up for 6 approximately 24 months (on average 16.9 months) were studied. The tumor diameter was 10 approximately 20 mm in 12 cases, 21 approximately 30 mm in 23 cases, >/= 31 mm in 11 cases, with the average value of 28 mm. RESULTS: The general tumor control rate was 91.3%. The useful hearing preservation rate was 100% immediately after radiosurgery, 87% 6 months later and 78% 2 years later. The hearing preservation rate was high for small tumors. The facial and trigeminal neuropathies began to appear after 6 months. The incidence rates of facial neuropathy was 15.3%, 7.6%, and 3.8% 6 months, 1 year and 2 years after radiosurgery respectively. The incidence rates of trigeminal neuropathy was 11.4%, 3.8%, and 3.8% respectively 6 months, 1 year, and 2 years after radiosurgery. The incidence of neuropathy was 3.8% for tumors with a diameter < 30 mm for both facial and trigeminal nerves. The hearing in 2 out of 15 cases with dysaudia began to improve 6 months after radiosurgery. The incidence of neuropathy for tumors with the diameter > 30 mm was 3.8% for both nerves 2 years after raadiosurgery. The preservation rate of useful hearing for tumors with the diameter < 20 mm was 100% after radiosurgery. CONCLUSION: Stereotactic radiosurgery using gamma knife with a dose of 12 approximately 15 Gy to the tumor margin succeeds in controlling acoustic schwannoma and preserving useful hearing. The incidence of facial and trigeminal neuropathies are low. The neuropathy caused by gamma knife radiosurgery is sub-lethal and can be recovered gradually.