Preoperative ultrasonography of the undescended testis.

In a prospective study during 1981-1983 42 boys aged 3-12 (mean 6.5) years were operated on for a palpable undescended testis. Twelve boys 3-8 (mean 4) years old were operated on for an unpalpable testis and 2 boys for an ectopic testis. The day before operation an ultrasound examination was performed. Reoperations were made on 11 patients and a bilateral operation on 2. In total, 69 ultrasound examinations were made. Comparison of the position at operation and ultrasound showed accordance in 47 of the 55 cases with only a slight variation of the position in 8 cases. Of the 12 non-palpated testes the ultrasonography showed 4 testicles, 3 non-testis-like formations and no finding in 5 cases. Exploration of these 5 latter cases showed an aplasia testis in 4 and a small intraabdominal testis in 1 boy. Preoperative ultrasonography can be recommended in case of an unpalpable testis in a boy not previously operated on in the inguinal area. Ultrasonography is particularly valuable before reaching a decision on hormonal therapy.