Which case is best for scrotal incision as the initial surgical approach in unilateral non-palpable testis?

Abstract

Approximately 50-70% of unilateral non-palpable testis are vanishing testis and almost all are located in the scrotum. Laparoscopy has been performed increasingly as the initial procedure for management of unilateral non-palpable testis, but is unnecessary except in the minority of intra-abdominal testis. The aim of this prospective study is to examine validity of the initial scrotal incision when unilateral non-palpable testes show contralateral testicular hypertrophy and palpable intra-scrotal nubbin. We prospectively enrolled 21 patients with unilateral non-palpable testes which confirmed by palpation under general anesthesia at our institute between May 2016 and April 2019. Contralateral testicular length and volume were measured with ultrasonography. A testicular length > 1.6 cm or testis volume > 1.0 ml was considered contralateral testicular hypertrophy. In cases where unilateral non-palpable testes show contralateral testicular hypertrophy and palpable intra-scrotal nubbin, the initial scrotal incision were performed. Of the 21 patients with unilateral non-palpable testis, 12 had (57.1%) vanishing testis with scrotal nubbin in 10, inguinal nubbin in 2. Among the remaining 9 patients with sizeable testes, 5 were intra-abdominal testis and 4 were peeping testis. Of the 10 cases of scrotal nubbin, initial scrotal incision was performed in 7 cases (70.0%). Initial laparoscopy was performed in 14 cases, of which 9 cases of sizeable testis, 3 cases of scrotal nubbin, and 2 cases of inguinal nubbin which showed contralateral testicular hypertrophy but no palpable nubbin in scrotum. Contralateral testicular hypertrophy and palpable intra-scrotal nubbin was significantly predictive with 70% sensitivity and 100% specificity (P<0.001). In patients with unilateral non-palpable testis, when palpable nubbin in scrotum and/or contralateral testicular hypertrophy are present, initial scrotal incision is appropriate. In the case of contralateral testicular hypertrophy with no palpable nubbin in the scrotum, initial inguinal incision is more appropriate. Other cases should proceed to laparoscopy.