Undescended Testis (UDT) and cryptorchidism testes (affecting 2-8% of full term and up to 30% of premature boys) describe testes not normally located at the bottom of the scrotum.
Points of note
The testis can be:
- Ectopic – in the superficial inguinal pouch or the femoral, pubopenile, perineal and crossed scrotal regions.
- UDT/Cryptorchid – not manipulated into the scrotum.
- Retractile – the testis can be manipulated into the scrotum and stays there without tension. Treatment: close observation until aged 10.
- Ascending – the testis can be manipulated into the upper scrotum, however it is under tension and retracts once released. Can be acquired after inguinal surgery (hernia and orchiopexy).
UDT can descend spontaneously by six months of age due to a spike in testosterone secretion (stimulation from pituitary gonadotropins). Spontaneous descent after this is very rare, hence surgery is indicated at age 6-9 months.
UDT can be congenital or acquired, unilateral (80%) or bilateral, and palpable (80%) or not.
Non–palpable testis (NPT) i.e. not felt during physical examination, can be due to anorchia (absence of testis) or an intra-abdominal location.
Children with bilateral NPT and UDT associated with hypospadias should be investigated for Disorders of Sexual Development.
Implications of UDT
Spermatogenesis requires 2-7 ºC less than body temperature with the scrotum providing an ideal environment.
Between 3 to 9 months of age, foetal/neonatal monocytes transform into adult spermatogonia. This transformation is impaired in UDT. Men with unilateral UDT have the same paternity rate as the normal population; however, men with bilateral UDT have a significant risk of infertility (30-60%). Early surgery improves the sperm count in unilateral and bilateral cases.
UDT is associated with a 2.5 to 5 fold increase in risk of Testicular Germ Cell Tumours(TGCT) – a risk reduced by early orchiopexy to ensure optimal germ cell development in the first year of life.
The aim for surgical treatment in UDT it to decrease or prevent the risk of TGCT, prevent the impairment of spermatogenesis, facilitate future examination of the testicle and treat inguinal hernia (90%) associated with UDT.
The timing of orchiopexy surgery is 6-12 month’s age, and for inguinal testes the success rate in terms of scrotal position and lack of atrophy is 82-89%.
Diagnostic laparoscopy via an umbilical port is the procedure of choice in NPT – ultrasound can evaluate inguinal testis well but is not reliable for an intra-abdominal testis. The presence of blind ending vessels on diagnostic laparoscopy is the hall mark of testicular atrophy/anarchia (due to prenatal torsion) (Figure 1a).
- Undescended testis is unlikely to descend after 5 months of (corrected gestational) age.
- Orchiopexy is indicated between 6 – 12 months of age.
- Diagnostic laparoscopy is gold standard to confirm absence of testis.
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