Diagnostic of non-palpable testis in children: laparoscopy or magnetic resonance imaging?

Laparoscopy and magnetic resonance imaging (MRI) are competetive tools in the diagnostic of non-palpable testis. Advantages and disadvantages of this methods will be demonstrate. 29 boys investigated for this indication with MRI. In case MRI failed to locate the testis laparoscopy was performed with a new miniaturized set of pediatric instruments (1.9 mm optic). The aim of laparoscopy was the identification of the spermatic duct and vessels and their topographic relation to the internal inguinal ring. All findings were verified by open surgical procedures. MRI revealed 10 inguinal and 7 abdominal testis. There was no false positive finding. In 12 boys MRI showed no testis. 4 cases were correct negative, 8 cases were false negative (32 %). In these 8 MRI-negative patients laparoscopy revealed 7 inguinal and 1 abdominal testis. The optical quality of the mini-telescope was sufficient for a 100 % correct diagnosis. Laparoscopy related complications did not occur. Laparoscopy proved to be a powerful low risk diagnostic method in non- palpable testis with high senitivity and specifity (100 % correct positive, 0 % false negative). Therefore lapraroscopy is recommended as primary diagnostic access for this indication. In the same anesthesia a optimal therapy is possible. Nevertheless a positive MRI-finding locates the testis reliably, whereas a negative finding always needs further exploration because testis might have been missed.