Impact of Preoperative Ultrasonographic Evaluation for Detection of a Viable Testis in Patients With a Unilateral Nonpalpable Testis

Objectives To investigate the impact of preoperative ultrasonography (US) for detecting a viable testis in patients with a unilateral nonpalpable testis. Methods Patients with a unilateral nonpalpable testis or unilateral palpable undescended testis who underwent preoperative US were enrolled. Patients were divided into 3 groups as follows: nonpalpable testis/no testis (n = 27), which included patients who had a unilateral nonpalpable testis with no viable testis detected at surgery; nonpalpable testis/viable testis (n = 10), which included patients who had a unilateral nonpalpable testis with a viable testis identified at surgery; and palpable undescended testis (n = 63), which included patients who had a unilateral palpable undescended testis. Preoperative US findings were compared among each group. Results The testicular volume on the contralateral descended side in the nonpalpable testis/no testis group was significantly greater than that in the nonpalpable testis/viable testis and palpable undescended testis groups. When a testicular volume of 0.54 mL was used as the cutoff value, the sensitivity, specificity, positive predictive value, and negative predictive value for the presence of the affected testis were 75.3%, 100%, 100%, and 60.0%, respectively. The testis on the affected side was detected in none of the nonpalpable testis/no testis group, 7 of the nonpalpable testis/viable testis group, and all of the palpable undescended testis group. When a visible testis on the affected side and a testicular volume of 0.54 mL or less were defined as positive, all patients in the nonpalpable testis/viable testis and palpable undescended testis groups had positive findings versus none in the nonpalpable testis/no testis group. Conclusions Preoperative US provides valuable information for predicting the presence of a viable testis in patients with a unilateral nonpalpable testis by estimating both the unaffected testis and the affected side.