Bostwick D G, Larson T R
Division of Anatomic Pathology, Mayo Clinic, Rochester, Minnesota 55905.
Prostate. 1995 Mar;26(3):116-22. doi: 10.1002/pros.2990260303.
Microwave irradiation administered by transurethral transducer to the prostate permits focused hyperthermia with resultant tissue ablation; a coding system within the catheter allows urethral preservation. We evaluated the effect of microwave hyperthermia in 13 dogs receiving 48-79 min of focused irradiation (16-45 watts, intraprostatic temperature > 45 degrees C) delivered by a specially-designed transducer with an operator-controlled directional antenna (T3, Urologix Inc., Minneapolis, MN); one other dog had transducer placement without irradiation (sham control). After treatment, the dogs were in good health, voiding well without complications, and were sacrificed after 5-38 days. The prostate and vasa deferentia were removed, fixed in 10% formalin, grossly inspected, cut at 5 mm intervals, and serially sectioned with whole mount sections; representative sections of the adjacent rectum and distal bladder were also obtained. All cases were histologically evaluated with prostatic mapping without knowledge of treatment or time of sacrifice. In the acute phase (5-13 days), the prostate showed sharply circumscribed periurethral coagulative necrosis with hemorrhage; necrosis was also seen in the mucosa and bladder wall of those with transducers placed at the bladder neck. In the subacute phase (17 days), the hemorrhagic necrosis was resolving, often with cystically dilated urethra due to sloughed necrotic tissue; the urothelium was intact. By 24-38 days, the necrosis was in the late stages of resolution, with residual patchy acute and chronic inflammation at the periphery, and frequent persistence of megalourethra. In all cases, the prostatic capsule was intact, the urethral mucosa was preserved, and the vasa deferentia and rectum were normal except for two cases with mild fat necrosis. Microwave irradiation allows precisely localized thermal ablation of prostatic tissue and enlargement of the urethral bore without clinical complications in dogs, offering promise as a therapeutic alternative to surgery in select patients with symptomatic prostatic nodular hyperplasia.
经尿道换能器对前列腺进行微波照射可实现聚焦热疗并导致组织消融；导管内的编码系统可保留尿道。我们评估了微波热疗对13只犬的影响，这些犬接受了48 - 79分钟的聚焦照射（16 - 45瓦，前列腺内温度>45摄氏度），照射由一个带有操作员控制定向天线的特殊设计换能器（T3，Urologix公司，明尼阿波利斯，明尼苏达州）进行；另一只犬进行了换能器放置但未照射（假对照）。治疗后，犬健康状况良好，排尿正常无并发症，在5 - 38天后被处死。取出前列腺和输精管，固定于10%福尔马林中，进行大体检查，每隔5毫米切片，并制作全层连续切片；还获取了相邻直肠和膀胱远端的代表性切片。所有病例均在不知治疗情况或处死时间的情况下进行前列腺图谱组织学评估。在急性期（5 - 13天），前列腺显示出界限清晰的尿道周围凝固性坏死并伴有出血；在膀胱颈部放置换能器的犬的黏膜和膀胱壁也可见坏死。在亚急性期（17天），出血性坏死正在消退，由于坏死组织脱落，尿道常呈囊性扩张；尿路上皮完整。到24 - 38天，坏死处于消退后期，周边残留散在的急性和慢性炎症，且常伴有巨尿道持续存在。在所有病例中，前列腺包膜完整，尿道黏膜得以保留，除两例有轻度脂肪坏死外，输精管和直肠均正常。微波照射可在犬体内精确地对前列腺组织进行局部热消融并扩大尿道内径，且无临床并发症，有望成为有症状的前列腺结节增生患者手术治疗的替代疗法。
