Risk Factors of Undescended Testis in Congenital Diaphragmatic Hernia: A Multicenter Study in Japan

This study aimed to examine the incidence of undescended testis (UDT) in congenital diaphragmatic hernia (CDH) and clinical risk factors for developing UDT.

Male patients with CDH born between 2006 and 2021 were retrospectively assessed for UDT using the database of the Japanese CDH study group. The UDT risk factors were examined by comparing patients with and without UDT.

Of the 605 boys with CDH, 408 were followed for at least one year and were included in this study. A total of 50 (12.3 %) of the 408 patients experienced UDT and orchidopexy was performed in 41 (10.2 %) patients. Twenty-four cases developed UDT on the same side of CDH, whereas only 6 cases developed UDT on the contralateral side of CDH; the remaining 20 cases were bilateral UDT. Comparison between the patients with and without UDT revealed significantly lower birth weight and lower Apgar Score in the patients with UDT. Furthermore, patients with UDT demonstrated a significantly higher rate of non-isolated, "liver-up", defect with C/D type, and patch closure. Multivariate analysis showed that the C/D type defect was deemed an independent risk factor for developing UDT.

The incidence of UDT and the need for orchidopexy are elevated in boys with CDH. In patients with CDH, UDT may tend to occur on the same side as that affected by CDH. The diaphragmatic large defect was considered to be an independent risk factor for UDT in CDH although different factors are thought to be involved in testicular descent.