How should a 20‑month‑old boy with bilateral non‑palpable testes, an empty left scrotum, a right communicating hydrocele, and inconclusive ultrasound be evaluated and managed—including the reliability of ultrasound for intra‑abdominal testes, the role of endocrine testing (anti‑Müllerian hormone, inhibin B, luteinizing hormone, follicle‑stimulating hormone, testosterone), indications for karyotyping, the need for examination under anesthesia and diagnostic laparoscopy, criteria for single‑stage orchidopexy versus staged Fowler‑Stephens orchiopexy, intra‑operative decision‑making for various testicular locations, and optimal timing of surgical intervention?

Management of Bilateral Nonpalpable Testes at 20 Months

This child requires urgent examination under anesthesia followed by diagnostic laparoscopy within the next 2–4 weeks, as he is already beyond the recommended 12–18 month window for orchidopexy, and further delay risks irreversible testicular damage. 1

Urgency of Surgical Intervention

At 20 months, this child is already past the critical 12–18 month deadline established by the 2025 EAU/ESPU guidelines. Histological studies demonstrate progressive loss of germ cells and Leydig cells in undescended testes by 12–18 months of age, making timely intervention essential for preserving future fertility and endocrine function 1. Every additional month of delay compounds the risk of permanent testicular damage. Schedule surgery as soon as feasible—ideally within 2–4 weeks.

Reliability of Ultrasound and Role of Additional Imaging

Ultrasound is unreliable for bilateral nonpalpable testes and should not delay surgical management. The 2025 EAU/ESPU guidelines explicitly state that "localisation studies using different imaging modalities usually provide no additional benefit" 1. The ultrasound in this case failed to locate either testis definitively, which is typical—ultrasound has only 45% sensitivity and 78% specificity for nonpalpable testes 2, 3. For intra-abdominal testes specifically, sensitivity drops to 48% 4.

MRI is not necessary. While MRI has better sensitivity than ultrasound, it is expensive, often requires sedation in young children, and does not change surgical management 3. The 2014 AUA guidelines explicitly recommend against routine imaging prior to referral 2. The only imaging exception would be if disorder of sex development (DSD) is suspected—then ultrasound to detect müllerian structures would be indicated 3.

Endocrine Evaluation Before Surgery

Endocrine testing is indicated in this case of bilateral nonpalpable testes to assess for anorchia and guide surgical planning. The 2014 AUA guidelines recommend measuring anti-müllerian hormone (AMH) or müllerian inhibiting substance in boys with bilateral nonpalpable testes who do not have congenital adrenal hyperplasia 2.

Obtain the following preoperative labs:

• AMH (anti-müllerian hormone): Produced by Sertoli cells; detectable AMH confirms presence of testicular tissue
• Inhibin B: Another Sertoli cell marker; levels <33.9 pg/mL predict Leydig cell dysfunction 5
• Baseline LH, FSH, and testosterone: Establish baseline gonadal function
• Consider hCG stimulation test if initial testosterone is low, though this is less reliable in isolation 2

These tests help differentiate between true bilateral cryptorchidism and bilateral anorchia (vanishing testes syndrome), which would obviate the need for extensive surgical exploration. However, do not delay surgery for endocrine testing—these can be drawn immediately and results reviewed before or during the surgical planning.

Karyotyping and DSD Evaluation

Karyotyping is NOT routinely indicated in this case because the child has a normal phenotypic male appearance with a right communicating hydrocele (indicating normal testicular descent pathway development on that side) and no mention of hypospadias, micropenis, or ambiguous genitalia 2.

Karyotyping and DSD workup ARE mandatory if:

• Bilateral nonpalpable testes in a newborn (to rule out congenital adrenal hyperplasia—a medical emergency) 2
• Associated hypospadias or micropenis 2, 5
• Ambiguous genitalia 2
• Ultrasound detection of müllerian structures 3

Since this child is 20 months old and has been stable without adrenal crisis, congenital adrenal hyperplasia is effectively ruled out. The presence of a communicating hydrocele on the right suggests normal Wolffian duct development and makes DSD unlikely.

Surgical Approach: Examination Under Anesthesia and Diagnostic Laparoscopy

The next step is examination under anesthesia (EUA) followed immediately by diagnostic laparoscopy if both testes remain nonpalpable. 1

Step 1: Examination Under Anesthesia

With the child fully relaxed under general anesthesia, perform a thorough bilateral groin and scrotal examination. The 2025 EAU/ESPU guidelines emphasize this as "an important step in surgery" because a previously nonpalpable testis may become palpable, fundamentally changing the surgical approach 1. If either testis becomes palpable during EUA, proceed with standard inguinal or scrotal orchidopexy on that side.

Step 2: Diagnostic Laparoscopy for Nonpalpable Testes

Diagnostic laparoscopy is the gold standard for locating nonpalpable testes, with nearly 100% sensitivity and specificity 1, 2, 3. The 2025 EAU/ESPU guidelines state that "the optimal approach for locating an intra-abdominal testis is diagnostic laparoscopy" 1.

Intraoperative Decision-Making Based on Laparoscopic Findings

During laparoscopy, you will encounter one of four anatomical scenarios for each testis 1:

Scenario 1: Spermatic Vessels Entering the Internal Inguinal Ring (40% of cases)

• Interpretation: Testis is in the inguinal canal or distal to the ring
• Management: Convert to inguinal exploration and perform standard orchidopexy via inguinal approach
• The testis is typically viable and can be brought to the scrotum with standard technique

Scenario 2: Intra-abdominal Testis (40% of cases)

• Interpretation: Testis is located within the abdomen, proximal to the internal ring
• Management: Decision depends on vessel length and testicular mobility (see detailed algorithm below)

Scenario 3: "Peeping" Testis at the Internal Ring (10% of cases)

• Interpretation: Testis is at the internal ring, partially visible
• Management: Can often be managed with laparoscopic or inguinal orchidopexy, depending on vessel length

Scenario 4: Blind-Ending Spermatic Vessels (10% of cases)

• Interpretation: Vanishing testis syndrome—testis underwent prenatal or perinatal torsion and atrophied
• Management: No further intervention needed for that side; document findings and remove any visible nubbin of tissue 1

Management of Bilateral Intra-abdominal Testes

If both testes are intra-abdominal, the decision between single-stage laparoscopic orchidopexy versus staged Fowler-Stephens procedure depends on testicular vessel length and whether the testis can reach the scrotum without tension 1.

Criteria for Single-Stage Laparoscopic Orchidopexy:

• Testis is close to the internal ring with adequate vessel length
• Testicular vessels are long enough to allow tension-free placement in the scrotum
• Perform laparoscopic-assisted orchidopexy, bringing the testis through the internal ring and into the scrotum

Criteria for Staged Fowler-Stephens Orchidopexy:

• Short testicular vessels that prevent tension-free scrotal placement
• High intra-abdominal testis (>2 cm above the internal ring is a common threshold)
• Stage 1: Clip or divide the testicular artery and vein laparoscopically, preserving collateral blood supply via the vas deferens and cremasteric vessels
• Stage 2: Perform orchidopexy 6 months later, once collateral circulation is established
• Alternative: Shehata technique (single-stage Fowler-Stephens with immediate orchidopexy after vessel division) 1

Important caveat: Laparoscopic orchidopexy for intra-abdominal testes carries "slightly higher rates of atrophy and retraction in comparison to the conventional inguinal approach, especially if a staged approach is required" 1. However, this must be balanced against the alternative of leaving the testes intra-abdominal, which guarantees progressive damage.

Can Both Sides Be Treated During the Same Operation?

Yes, both sides can and should be addressed during the same operation whenever feasible. The 2025 EAU/ESPU guidelines do not contraindicate bilateral simultaneous orchidopexy. In fact, addressing both sides in one procedure:

• Minimizes anesthesia exposure
• Reduces family burden and time away from normal development
• Prevents further delay in treating the contralateral testis

Specific scenarios:

• Both testes suitable for single-stage orchidopexy: Perform bilateral orchidopexy in the same operation
• One or both require staged Fowler-Stephens: Perform Stage 1 (vessel division) bilaterally, then Stage 2 bilaterally 6 months later
• Mixed findings (e.g., one vanishing testis, one viable): Perform orchidopexy on the viable side and document/remove nubbin on the other side

Management of Right Communicating Hydrocele

The right communicating hydrocele should be repaired during the same operation as the orchidopexy. A communicating hydrocele indicates a patent processus vaginalis, which is routinely ligated during inguinal orchidopexy.

Surgical approach:

• If the right testis is found in the inguinal canal or becomes palpable during EUA, perform standard inguinal orchidopexy with high ligation of the processus vaginalis
• If the right testis is intra-abdominal and requires laparoscopic orchidopexy, the internal ring will be addressed during the laparoscopic portion, effectively treating the hydrocele
• If the right testis is absent (vanishing testis), still ligate the patent processus vaginalis to prevent future hydrocele or hernia

Step-by-Step Management Algorithm

Preoperative Phase (Complete Within 1–2 Weeks):

1. Draw endocrine labs: AMH, inhibin B, LH, FSH, testosterone
2. No additional imaging (ultrasound already done and uninformative; MRI not indicated)
3. No karyotype unless DSD features present (hypospadias, micropenis, ambiguous genitalia)
4. Schedule surgery urgently—within 2–4 weeks given the child's age

Operative Phase:

1. Examination under anesthesia: Thorough bilateral groin/scrotal palpation

   • If either testis becomes palpable → proceed with standard orchidopexy on that side
   • If both remain nonpalpable → proceed to laparoscopy

2. Diagnostic laparoscopy: Systematically examine both internal rings

   • Document findings for each side (vessels entering ring, intra-abdominal testis, peeping testis, or blind-ending vessels)

3. Intraoperative decision-making for each testis:

   • Vessels entering ring → inguinal exploration and standard orchidopexy
   • Intra-abdominal with adequate vessel length → single-stage laparoscopic orchidopexy
   • Intra-abdominal with short vessels → staged Fowler-Stephens (clip vessels, return in 6 months)
   • Blind-ending vessels → document vanishing testis, remove nubbin if present
   • Peeping testis → laparoscopic or inguinal orchidopexy based on mobility

4. Address right hydrocele: High ligation of processus vaginalis during orchidopexy or as separate step if right testis is absent

5. Bilateral simultaneous treatment: Perform definitive management on both sides during the same operation whenever possible

Postoperative Follow-up:

1. Immediate postoperative (2–4 weeks): Wound check, assess testicular position and size
2. 3–6 months: Clinical examination to confirm bilateral scrotal position, assess testicular size and consistency
3. Annual follow-up through puberty: Monitor testicular growth, pubertal development
4. Endocrine reassessment at puberty: LH, FSH, testosterone, semen analysis when age-appropriate
5. Lifelong testicular self-examination education: Increased risk of testicular cancer (not limited to the undescended testis) 1

Critical Pitfalls to Avoid

Do not delay surgery for additional imaging. Ultrasound and MRI will not change management and only postpone necessary intervention 1, 2, 3.

Do not assume bilateral vanishing testes without surgical confirmation. Even with negative imaging and low AMH, diagnostic laparoscopy is required to definitively rule out intra-abdominal testes 2.

Do not perform unilateral orchidopexy and "wait and see" on the contralateral side. Both sides must be addressed, as bilateral cryptorchidism carries compounded fertility risks 1, 6.

Do not underestimate the urgency. At 20 months, this child has already exceeded the 12–18 month guideline window. Each additional month increases the risk of irreversible germ cell loss, Leydig cell dysfunction, and future infertility 1, 6.

Do not forget that unilateral cryptorchidism can damage the contralateral descended testis through mechanisms including genitofemoral nerve injury, increased oxidative stress, and antisperm antibody production 6. Bilateral nonpalpable testes compound these risks.

Recognize that even with successful orchidopexy, fertility may be compromised. The association between undescended testes and impaired fertility is multifactorial, involving germ cell loss, impaired maturation, Leydig cell diminution, and testicular fibrosis 1, 6. Set realistic expectations with the family regarding future reproductive potential, emphasizing that early intervention optimizes but does not guarantee normal fertility.