An undescended testicle, medically termed Cryptorchidism, is a common condition where one or both testicles fail to move into the scrotum before or shortly after birth. This affects about 3% of full-term and up to 30% of premature infant boys. When a physical examination cannot definitively locate the testicle, an ultrasound scan is often ordered. This non-invasive imaging method helps determine the testicle’s position, guiding the appropriate course of action.
Defining Cryptorchidism and the Role of Imaging
Cryptorchidism means the testicle is located somewhere along its normal descent path, such as the inguinal canal or abdomen. The condition involves the testicle being situated along this path, from the abdomen, through the inguinal canal, and toward the scrotum. Rarely, it may be in an ectopic location, having deviated from this path. Diagnosis begins with a physical examination, but this method is limited when the testicle is non-palpable, which occurs in 20% to 30% of cases.
Imaging is necessary when the testicle is not palpable or when the physical exam cannot distinguish it from a retractile testicle. A retractile testicle moves between the scrotum and groin but can be gently guided into the scrotum, requiring no treatment. Ultrasound is the preferred initial imaging choice because it is widely available, non-invasive, and safe for infants, as it does not use ionizing radiation.
The primary goal is to confirm the testicle’s location, typically focusing on the inguinal canal, which is the most common site. However, ultrasound has technical limitations for truly non-palpable testes, especially those situated high in the abdomen. Abdominal testes can be obscured by bowel gas or mistaken for other structures, leading to low sensitivity in these cases.
Preparing For and Undergoing the Ultrasound Scan
The ultrasound procedure is straightforward, requiring minimal preparation, and is completed quickly, usually within 15 to 30 minutes. There are typically no dietary or fasting restrictions necessary, which is beneficial when scanning infants. The child lies down, and a clear, water-based gel is applied to the examination areas to help sound waves transmit effectively.
A small handheld transducer is gently moved across the skin of the groin and lower abdomen. The transducer emits high-frequency sound waves that bounce off internal structures, creating a real-time image on a monitor. The sonographer systematically scans the normal path of descent, from the kidneys down to the scrotum, to locate the organ. The procedure is painless, though the gel may feel cold.
Interpreting the Results and Determining Treatment Pathways
The sonographer and radiologist carefully analyze the images, looking for specific characteristics of the testicle. They assess its location, size, and internal structure. Doppler technology may also be used to check for blood flow, which indicates viability. A normal undescended testicle appears as an ovoid structure that is slightly less echogenic than a normally descended testicle.
Common results include finding the testicle in the inguinal canal, an ectopic location, or not visualizing it at all. The ultrasound findings directly guide clinical decision-making. If the testicle is clearly located in the inguinal canal, the path to surgical correction is well-defined.
If the ultrasound is negative (testicle not found), it suggests the testicle may be intra-abdominal, severely atrophic, or entirely absent. These outcomes require further investigation, such as diagnostic laparoscopy. Reduced size or poor blood flow may indicate testicular atrophy, meaning the tissue is non-viable.
For newborns, a period of “watchful waiting” is often recommended, as approximately 80% of undescended testicles spontaneously descend within the first six months of life. If descent has not occurred by six months of age, spontaneous movement is highly unlikely, and surgical intervention is necessary.
The standard surgical procedure is Orchiopexy, typically performed between six and eighteen months of age. During this procedure, the surgeon moves the testicle into the scrotum and secures it in place. This early intervention is performed to reduce the risk of long-term complications, including impaired fertility and increased risk of testicular cancer in adulthood.