Undescended Testis “Basic to Clinical Practice”
@ Asian Congress of Urology / Thai Urological Association 23 Aug 2012
By Dr Clarence Lei Chang Moh, FRCS (Urol), FEBU, Consultant Urologist
clarencelei@gmail.com; WA: +60128199880; kuchingurology.com
Undescended testis (UDT) is defined as a testis which has failed to descend to the scrotum and is retained at some point along its path of descent. The gonads first appear in intra-uterine life around the 2nd month at the lumbar area and descends under the influence of androgens and shortening of the gubernaculum. The cause of UDT is thought to be due to hormonal or genetic defects. Nevertheless, hormonal manipulation after delivery is of limited value in UDT. The incidence of UDT at birth is estimated to be about 4% and 1% at 1 year of age. Therefore, surgical treatment is recommended around 1 year of age.
The management of UDT depends on the following factors: unilateral or bilateral, whether ectopic, the location and size of the testis. 80% of UDT are palpable. Retractile testis may be observed. If the testis is not palpable in an obese groin, a good quality ultrasound of the groin may help to locate the testis in the groin or just at deep ring; sensitivity in identifying inguinal testis is 95%. MRI & CT may not be useful to locate the intraabdominal position. The definitive investigation is a laparoscopy and if only a nubbin is found, it is not necessary to excise it.
Almost all bilateral intraabdominal testes would be infertile, if not operated. Germ cell depletion is noted in 55% of testicular biopsies of intra-abdominal testes at 12 months (AbouZeid). On the other end of spectrum, fertility is almost normal if there is a unilateral descended normal testis. 93% of UDT have absent germ cells on biopsy. There is an increased relative risk of malignancy in the UDT, 2.75 to 8 times, with an absolute risk of 1%. The risk of cancer would be when the patient is 15 to 30 years old. The peritoneal invagination of the processes vaginalis follows the course of the gubernaculum and when patent, increases the UDT to torsion, trauma and hernia formation. These are additional reasons for surgical treatment. Surgery is usually a one-stage orchidopexy, performed under magnification, Prentiss manoeuvre if necessary. After orchidopexy, malignant risk is still present, with more cases of non-seminoma. If it is not possible to bring intraabdominal testis to the scrotum, one can do a two-stage procedure by performing a high ligation of the spermatic vessels during the first stage (Fowler Stephen). The 2ndstage operation may be performed 6 to 12 months later, doing one side at a time.
Updated 14 February 2021
References:
AbouZeid et al Intraabdo testes Biopsy J Urol 2011, 185- 269-274
Fowler Stephen J Urol 1996, 156:802
Jack Elder J Urol 2009, 181: 452-461
Prentiss, J Pediat Urol 2012 (8): 488
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