Ejaculatory Duct Obstruction and TURED
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Direct answer
Ejaculatory duct obstruction (EDO) is a correctable cause of male infertility in which blocked terminal ejaculatory ducts prevent seminal vesicle secretions from entering the urethra, producing the pathognomonic quartet of azoospermia or severe oligospermia, semen volume under about 1.5 mL, acidic ejaculate pH, and absent or greatly reduced fructose, with palpable vasa and normal gonadotrophins. Transrectal ultrasound shows dilated seminal vesicles (over about 1.5 cm) and a dilated ejaculatory duct or a midline cyst. Treatment is transurethral resection of the ejaculatory ducts (TURED), unroofing the ducts through the verumontanum, which restores sperm to the ejaculate in a majority with complete obstruction.
What you must remember
- The biochemical signature: low volume, acidic pH (seminal vesicle fluid is alkaline), fructose absent or minimal — fructose comes from the seminal vesicles.
- Both vasa palpable on examination plus normal FSH and testosterone plus azoospermia equals obstruction somewhere: duct versus ejaculatory duct is the next question.
- Causes: midline prostatic cysts (Mullerian duct remnants), Wolffian duct cysts, calculi in the duct or seminal vesicle, post-inflammatory strictures, and obstruction after transurethral surgery.
- TRUS is the diagnostic cornerstone: dilated seminal vesicles (anterior-posterior diameter above roughly 1.5 cm), dilated ejaculatory ducts, cysts or stones.
- Seminal vesicle aspiration finding sperm supports the diagnosis and can provide sperm for assisted reproduction.
- TURED complications: reflux of urine into the ejaculatory ducts and seminal vesicles (watery, foul ejaculate), retrograde ejaculation, and urethral stricture; rectal injury is rare but catastrophic.
- Partial obstruction (low volume with oligospermia) is a recognised, subtler variant; TURED outcomes are less predictable here.
Locating the block in an azoospermic man, step by step
A 30-year-old with primary infertility has azoospermia on two analyses; volume is 0.8 mL, pH 6.8, fructose absent. Examination: both vasa palpable, testes 16 mL, normal virilisation; FSH 5 mIU/mL. The reasoning: normal testicular volume with normal FSH and palpable vasa makes obstructive azoospermia near-certain; the low volume and absent fructose localise the lesion distal to the seminal vesicle orifices — that is, the ejaculatory ducts — because a block at the epididymis or vas would still allow seminal vesicle fluid (alkaline, fructose-rich, the bulk of volume) through.
Confirm with TRUS: dilated seminal vesicles and a midline cyst at the level of the prostate clinch it. The operation: cystoscopic resection through the verumontanum in the direction of the ducts (classically at the 5 and 7 o'clock or midline for a cyst), unroofing until the duct lumen or cyst cavity is entered — often signalled by a gush of cloudy, sperm-laden fluid. Semen analysis at six to twelve weeks shows sperm in a majority with complete obstruction, and natural pregnancies follow in a meaningful proportion; failures proceed to sperm retrieval with ICSI, and sperm aspirated from the seminal vesicle at diagnosis can be cryopreserved as insurance.
Where students slip
The sequence "azoospermia, check FSH, high means non-obstructive" is learned by everyone; the exam separates candidates on the low-volume detail. A stem with volume 0.9 mL and absent fructose is pointing at the ejaculatory duct or seminal vesicle, and the next investigation is TRUS — not testicular biopsy. The second slip is forgetting that urine reflux after TURED explains the post-operative complaint of a clear or foul-smelling ejaculate; it is a known sequela, not necessarily infection. Third, candidates overlook that vasography, once standard, has largely been replaced by TRUS and MRI, and that open seminal vesicle surgery is a last resort for stones or symptomatic cysts.
Frequently asked questions
What semen parameters suggest ejaculatory duct obstruction?
Azoospermia or severe oligospermia with volume under about 1.5 mL, acidic pH and absent or markedly reduced fructose, in a man with palpable vasa and normal gonadotrophins.
Which investigation diagnoses ejaculatory duct obstruction?
Transrectal ultrasound, showing dilated seminal vesicles (over about 1.5 cm), dilated ejaculatory ducts, or midline cysts and calculi along the duct course.
What is TURED?
Transurethral resection of the ejaculatory ducts — endoscopic unroofing of the ducts through the verumontanum to relieve obstruction and restore sperm passage.
What are the complications of TURED?
Urine reflux into the ejaculatory ducts and seminal vesicles causing watery ejaculate, retrograde ejaculation, urethral stricture, and rarely rectal injury.
Why is fructose absent in ejaculatory duct obstruction?
Seminal fructose is produced by the seminal vesicles; obstruction at the ejaculatory duct blocks its entry into the posterior urethra, so the ejaculate lacks both volume and fructose.