Undescended Testis Flashcards
What is the pathophysiology of undescended testis?
The testes develop in the abdomen and descend into the scrotum under the influence of multiple factors, including traction on the testis by scrotal attachments, body wall growth, intra-abdominal pressure, epididymal maturation, and hormonal influences.
When does the testicle begin to descend during fetal development?
The testicle begins to form near the developing kidney before the 2nd fetal month. It descends in two phases:
- Abdominal phase (weeks 8-15): Migration from the kidney to the internal inguinal ring.
- Inguinal phase (weeks 28-35): The testicle moves through the internal ring, inguinal canal, external ring, and into the scrotum.
What can alter the descent of the testicle?
The descent of the testicle can be altered at any step along the process, during either the abdominal or inguinal phase.
Why should undescended testes be surgically transferred to the scrotum?
There are several reasons for surgical correction:
- The scrotum is 2-3°C cooler, which is optimal for post-pubertal testicular development and sperm production.
- Provides cosmetic and psychological benefits.
- The testes are less vulnerable to injury when they are in the scrotum.
- Testicular tumours are the most common solid tumours in males aged puberty to 40 years; scrotal testes can be easily monitored for potential issues.
What is the incidence of undescended testes in full-term and preterm boys?
The incidence is 3-5% in full-term boys, and 1.8% at 1 year of age.
33% of preterm babies will have undescended testes.
What percentage of testicles typically descend by 9 months of age?
About 65% of testicles typically descend by 9 months.
What should be considered if undescended testes are accompanied by abnormal genitalia?
Undescended testes with abnormal genitalia require a genetic and hormonal workup to investigate underlying causes.
How should the patient be positioned during a clinical examination for undescended testes?
The patient should be warm and relaxed to facilitate a proper examination
What should be checked when examining the penis in a patient with suspected undescended testes?
Ensure the penis is of normal shape and exclude conditions such as an ectopic urethral meatus (hypospadias).
What should be assessed in the scrotum during the examination?
Look for signs of poor development, such as scrotal hypoplasia.
Check for a bifid scrotum, which may indicate an underlying condition.
How should the testes be palpated during an examination for undescended testes?
- Check both the scrotum and groin.
- Lubricate the groin with soap and slide fingers from the external inguinal ring toward the scrotum.
- Trap the testicle by holding the hand in position and palpate the scrotum to locate the testis.
-Invert the scrotal skin if necessary.
When is ultrasound or imaging necessary in the evaluation of undescended testes?
Ultrasound or other imaging modalities are usually unnecessary. If physical examination findings are unclear, refer the patient to a paediatric surgeon for further assessment.
What are the three possible causes of impalpable testes?
The three possibilities are:
- Abdominal Testis: Located inside the abdominal cavity along the natural descent pathway (8% of cases).
- Ectopic Testicle: Found outside the normal descent pathway (5 major sites: perineum, femoral canal, superficial inguinal pouch, suprapubic area, and contralateral scrotal pouch).
- Absent Testicle: Can be bilateral and may result from in utero torsion, vascular insult, or agenesis (4% of cases).
What is the location and characteristic of a testicle located above the scrotum but outside the abdominal cavity?
The testicle is located above the scrotum but outside the abdominal cavity (72% of cases).
The testes are palpable in the groin but cannot be milked down into the scrotum.
What is retractile testis, and when does it usually occur?
A retractile testis can be milked down into the scrotum and will remain there once the cremaster muscle is exhausted (after several seconds of traction).
It is most common at ages 5-6 years.
Between ages 1-11 years, 80% of fully descended testes can retract due to a hyperactive cremaster muscle.
This is a normal variation and usually improves by puberty.
How can normally descended testes be identified on clinical examination?
Normally descended testes are palpable in the scrotum.
What is the mainstay treatment for undescended testis?
The mainstay treatment is surgical exploration and orchidopexy, typically performed around 9 months of age, as early damage to germ cells begins at this age.
What is the management for retractile testis?
No surgery is needed for retractile testes. Annual monitoring is recommended, as the condition usually improves by puberty.
What is the treatment for canalicular testis?
Exploration and open orchidopexy via a groin incision is performed.
After removal of the hernial sac, the testis is delivered into the scrotum and anchored in a sub-dartos pouch.
How is a non-palpable testis managed surgically?
Laparoscopy is the procedure of choice.
If the vas and vessels exit the abdominal cavity through the internal ring, groin exploration is performed. Either a nubbin of tissue is removed, or the vessels are followed to locate the testis, which is then placed in the scrotum.
If the testis is low in the abdomen and mobile, a laparoscopically assisted orchidopexy is performed through a small opening in the scrotum.
If the testis is high in the abdomen, the testicular artery is divided, and revascularization occurs. Pexy to the scrotum is performed in a second-stage operation 6 months later.
If a very abnormal gonad is found, orchidectomy is performed.
What are the complications of orchidopexy surgery for undescended testis?
Bleeding
Infection
These complications are uncommon.
How does orchidopexy affect fertility in boys with undescended testes?
Fertility is less likely to be normal in 40% of unilateral cases and 70% of bilateral cases.
Early orchidopexy should optimize fertility outcomes.
How does undescended testis affect the risk of tumorigenesis?
- An undescended testis is 20-48 times more likely to undergo malignant degeneration.
- Orchiopexy does not alter the risk of malignant transformation.
- The risk is also increased in the unaffected testis.
- At puberty, boys should be taught to perform monthly testicular self-examinations.
Seminoma is the most common type of testicular tumor.
