Dynamic three-dimensional spiral computed tomographic cysto-urethrography: a novel technique for evaluating post-traumatic posterior urethral defects

OBJECTIVE

To present a new method of identifying the anatomy of posterior urethral distraction defects (PUDDs) using three-dimensional spiral computed tomography/cysto-urethrography (CTCUG), as conventional two-dimensional CUG can give a false interpretation of the exact anatomy.

PATIENTS AND METHODS

Twenty-one patients presenting with a PUDD were assessed between February 2001 and October 2002. All patients initially underwent combined ascending and micturating CUG (ACUG), followed by CTCUG analysed using special software. In this technique all soft-tissue densities were subtracted from the volume of interest leaving only high-density images, i.e. pelvic bony structure and the contrast medium-filled bladder and urethra. The images were taken over a sequence and 36 different images viewed by 'roll and spin' techniques, each of which had a different plane of vision. Images were supplied as static CT films and as a movie on a compact disk using a computer program.

RESULTS

The technique allows one CT image to be viewed from 36 different angles both dynamically and statically, allowing the surgeon the unique opportunity to view the PUDD through several planes and precisely identify its anatomy. By comparing the data obtained with this technique to those obtained by conventional ACUG, and each in relation to the operative findings, the following aspects could be more thoroughly evaluated by CTCUG: the location of the distraction injury, the length of the distraction defect, the degree and direction of urethral end-alignment, the relation of the ectopic bony fragments and bone callus to the urethra, and the presence of various pathological defects, e.g. fistulae, false passages and diverticulae.

CONCLUSION

With CTCUG, both static and dynamic images can be obtained, allowing the easier staging of a PUDD and thus better surgical planning and consequently better results from reconstruction.

Perineal subcutaneous dartos pedicled flap as a new technique for repairing urethrorectal fistula

PURPOSE

Urethrorectal fistulas are rare, and the etiology is usually traumatic or iatrogenic (postoperative). Several operative approaches and techniques have been used for fistulous repair but no procedure has proved to be the best or universally acceptable. We present a new technique for repairing urethrorectal fistulas.

MATERIALS AND METHODS

We successfully treated 12 male patients 7 to 65 years old who presented with urethrorectal fistula from 1990 to 1997 using the perineal subcutaneous dartos pedicled flap procedure. Urethrorectal fistulas resulted from crush pelvic injury in 6 cases and gunshot in 2, and developed after prostatectomy in 4. The fistula was associated with urethral stricture in 4 cases. A perineal approach was used in all cases of urethrorectal fistula and combined with the transsymphyseal approach in the 4 patients with posterior urethral stricture. We interposed a subcutaneous dartos pedicled flap as a vascularized tissue flap between the repaired rectum and urethra.

RESULTS

The results of our technique were excellent in all cases. No leakage or perineal collection developed and there was no fistula recurrence. In 1 patient urethral stricture was managed by visual internal urethrotomy. Loss of the internal and external sphincters resulted in urinary incontinence in 4 cases, involving gunshot injury (2), crush pelvic injury (1) and prostatectomy (1). Followup ranged from 9 to 42 months.

CONCLUSIONS

Our technique of a perineal subcutaneous dartos pedicled flap fulfills all principles of the successful repair of urethrorectal fistula. We consider it to be an ideal solution to this urological dilemma.