Undescended testis and orchiopexy

👶 Anatomy & Development - The Great Descent

• Gubernaculum: Fibromuscular cord anchoring fetal testis to the labioscrotal swelling; guides descent.
• Processus Vaginalis: Peritoneal outpouching preceding the testis through the inguinal canal. Normally obliterates after descent.
  • ⚠️ Failure to obliterate → indirect inguinal hernia or communicating hydrocele.

⭐ The inguinoscrotal phase is androgen-dependent. This is why conditions causing androgen insensitivity can lead to undescended testes located in the inguinal canal.

⚙️ Pathophysiology - Why It Gets Stuck

• Normal Descent (Two Phases):
  • Transabdominal (8-15 wks): Testis moves to the internal inguinal ring, driven by AMH & INSL3.
  • Inguinoscrotal (25-35 wks): Testis descends into the scrotum; this phase is androgen-dependent and guided by the gubernaculum & CGRP.
• Arrest Factors:
  • Hormonal: ↓ Androgens, ↓ AMH, or receptor defects.
  • Mechanical: Gubernaculum dysfunction or anatomical obstruction.
  • Neural: Genitofemoral nerve (CGRP) dysfunction.

⭐ The most common location for a palpable undescended testis is the superficial inguinal pouch, just outside the external inguinal ring.

🕵️‍♂️ Diagnosis - The Search Party

• Primarily a clinical diagnosis via careful physical exam (warm room, relaxed child).
• Palpable Testis: Found along the path of descent (e.g., inguinal canal). Differentiate from a retractile testis, which can be brought into the scrotum.
• Non-palpable Testis: Cannot be felt in the inguinal region or scrotum, prompting further workup.

⭐ For a non-palpable testis, laparoscopy is both diagnostic (locates testis or confirms agenesis via blind-ending vessels) and therapeutic (can proceed to orchiopexy).

🗺️ Management - The Relocation Plan

• Observation: Spontaneous descent is common in the first 3-6 months; re-evaluate at the 6-month well-child visit.
• Surgical Indication: Orchiopexy is required if the testis remains undescended by 6 months.
• ⚠️ Hormonal Therapy (hCG/GnRH): Not recommended due to low efficacy and side effects.

⭐ Optimal window for orchiopexy is 6-12 months. Surgery before 1 year maximizes fertility potential and may reduce (but not eliminate) the lifelong risk of testicular germ cell tumors.

🔭 Complications - Long-Term Lookout

• Testicular Cancer: ↑ risk (3-8x), even post-orchiopexy.
  • Seminoma is the most common histology.
  • Risk is highest for intra-abdominal testes.
• Subfertility/Infertility:
  • Risk persists, especially if bilateral or repair is delayed >1 year.
  • Orchiopexy improves semen parameters but doesn't guarantee normal fertility.
• Testicular Torsion & Inguinal Hernia:
  • Slightly ↑ torsion risk.
  • Hernia is common (patent processus vaginalis).

⭐ Orchiopexy does not eliminate malignancy risk but moves the testis to a palpable location, facilitating crucial self-examination and earlier detection.

⚡ Biggest Takeaways

• Most undescended testes descend spontaneously by 6 months; watchful waiting is key.
• Orchiopexy is performed between 6-12 months to preserve Sertoli cell function and fertility.
• Major risks include infertility, testicular torsion, and an associated indirect inguinal hernia.
• There is a significantly increased risk of seminoma, the most common testicular cancer.
• Orchiopexy does not eliminate cancer risk but facilitates early detection via self-examination.
• Diagnosis is clinical; laparoscopy is used for non-palpable, intra-abdominal testes.