Why is catheterisation difficult in hypospadias?

Why Catheterisation is Difficult in Hypospadias

Catheterisation in hypospadias is difficult because the urethral meatus is abnormally positioned proximal to its normal glanular location—anywhere along the ventral penile shaft, scrotum, or perineum—making standard catheter insertion technically challenging or impossible through the displaced opening. 1, 2

Anatomical Abnormalities That Complicate Catheterisation

Abnormal Meatal Position

• The urethral opening is located on the ventral (underside) aspect of the penis rather than at the tip of the glans, with severity ranging from just below the glans (coronal) to the scrotum or perineum in proximal cases 1, 2, 3
• In proximal hypospadias, the meatus may be so far displaced that identifying the correct opening becomes challenging, particularly in severe perineal forms where sex determination at birth can be difficult 3

Associated Structural Defects

• Ventral penile curvature (chordee) is commonly present, creating an angulated path that prevents straight catheter advancement 1, 2, 3
• The corpus spongiosum is atrophic and underdeveloped, providing inadequate support for catheter passage 1
• A dorsally redundant prepuce (hooded foreskin) can obscure anatomical landmarks and make meatal identification more difficult 1

Post-Surgical Complications

• Urethral stricture formation is a common complication after hypospadias repair, occurring in a significant proportion of patients and creating additional obstruction to catheter passage 4, 3
• Recurrent ventral curvature develops in approximately 26% of patients after proximal hypospadias repair, even after initial straightening procedures, further complicating catheter trajectory 5
• Fistula formation and glans dehiscence can create false passages that misdirect catheter insertion 6

Clinical Approach When Catheterisation is Required

Pre-Catheterisation Assessment

• Identify the exact meatal position through careful inspection of the ventral penile surface, scrotum, and perineum 1, 2
• Assess for ventral curvature that will affect catheter trajectory 1, 3
• Review surgical history to anticipate stricture locations or anatomical alterations from prior repairs 4

Catheterisation Technique Modifications

• Use smaller caliber catheters (pediatric sizes) to navigate the narrowed or angulated urethra 4
• If urethral catheterisation fails or urethral injury is suspected, place a suprapubic catheter for drainage 7, 8
• Consider guidewire-assisted catheter placement to prevent false passage formation, particularly if stricture is suspected 4

When to Avoid Urethral Catheterisation

• Do not attempt blind catheter passage if blood is present at the meatus or urethral injury is suspected—perform retrograde urethrography first 4, 8
• In patients with known urethral stricture from prior hypospadias surgery, consider suprapubic catheterisation as first-line to avoid exacerbating the stricture 4, 7
• If initial catheterisation attempts are unsuccessful, proceed directly to suprapubic cystostomy rather than repeated traumatic attempts 4, 7

Common Pitfalls to Avoid

• Never force a catheter through resistance in hypospadias patients, as the abnormal anatomy and potential strictures create high risk for false passage creation, urethral perforation, or rectal injury 4
• Do not assume the meatus is in the normal glanular position—always inspect the entire ventral surface before attempting catheterisation 1, 2
• Avoid repeated instrumentation attempts in patients with prior hypospadias repair, as this increases morbidity and can worsen existing strictures 4
• In proximal hypospadias with severe curvature, standard straight catheter insertion may be anatomically impossible—early transition to suprapubic access prevents unnecessary trauma 7, 5