Urinary continence after repair of membranous urethral stricture in prostatectomized patients

Reconstruction of Membranous Urethral Strictures

PURPOSE OF REVIEW

Due to the proximity of the rhabdosphincter and cavernous nerves to the membranous urethra, reconstruction of membranous urethral stricture implies a risk of urinary incontinence and erectile dysfunction. To avoid these complications, endoscopic management of membranous urethral strictures is traditionally favored, and bulboprostatic anastomosis is reserved as the main classical approach for open reconstruction of recalcitrant membranous urethral stricture. The preference for the anastomotic urethroplasty among reconstructive urologists is likely influenced by the familiarity and experience with trauma-related injuries. We review the literature focusing on the anatomy of membranous urethra and on the evolution of treatments for membranous urethral strictures.

RECENT FINDINGS

Non-traumatic strictures affecting bulbomembranous urethra are typically sequelae of instrumentation, transurethral resection of the prostate, prostate cancer treatment, and pelvic irradiation. Being a different entity from trauma-related injuries where urethra is not in continuity, a new understanding of membranous urethral anatomy is necessary for the development of novel reconstruction techniques. Although efficacious and durable to achieve urethral patency, classical bulboprostatic anastomosis carries a risk of de-novo incontinence and impotence. Newer and relatively less invasive reconstructive alternatives include bulbar vessel-sparing intra-sphincteric bulboprostatic anastomosis and buccal mucosa graft augmented membranous urethroplasty techniques. The accumulated experience with these techniques is relatively scarce, but several published series present promising results. These approaches are especially indicated in patients with previous transurethral resection of the prostate in which sparing of rhabdosphincter and the cavernous nerves is important in attempt to preserve continence and potency. Additionally, introduction of buccal mucosa onlay grafts could be especially beneficial in radiation-induced strictures to avoid transection of the sphincter in continent patients, and to preserve the blood supply to the urethra for incontinent patients who will require artificial urinary sphincter placement. The evidence regarding erectile functional outcomes is less solid and this item should be furtherly investigated.

Mechanism of continence after repair of posterior urethral disruption: evidence of rhabdosphincter activity

PURPOSE

Controversy exists regarding continence mechanisms in patients who undergo posterior urethral reconstruction after pelvic fracture. Some evidence suggests that continence after posterior urethroplasty is maintained by the bladder neck or proximal urethral mechanism without a functioning distal mechanism. We studied distal urethral sphincter activity in patients who have undergone posterior urethroplasty for pelvic fracture.

MATERIALS AND METHODS

A total of 12 patients who had undergone surgical repair of urethral disruption involving the prostatomembranous region underwent videourodynamics with urethral pressure profiles at rest, and during stress and hold maneuvers. Bladder pressure and urethral pressure, including proximal and distal urethral sphincter activity and pressure, were assessed in each patient.

RESULTS

All 12 patients had daytime continence of urine postoperatively with a followup after anastomotic urethroplasty of 12 to 242 months (mean 76). Average maximum urethral pressure was 71 cm H2O. Average maximum urethral closure pressure was 61 cm H2O. The average urethral pressure seen during a brief hold maneuver was 111 cm H2O. Average functional sphincteric length was 2.5 cm. Six of the 12 patients had clear evidence of distal urethral sphincter function, as demonstrated by the profile.

CONCLUSIONS

Continence after anastomotic urethroplasty for posttraumatic urethral strictures is maintained primarily by the proximal bladder neck. However, there is a significant contribution of the rhabdosphincter in many patients.

Mechanism of continence after repair of post-traumatic posterior urethral strictures

OBJECTIVES

To determine the mechanism of urinary continence after repair of post-traumatic posterior urethral strictures by perineal anastomotic urethroplasty.

METHODS

Two groups of male patients were enrolled in this study. Group 1 consisted of 8 patients (mean age 31 years) who had undergone bulboprostatic anastomotic urethroplasty for strictures complicating a pelvic fracture urethral disruption. Group 2 consisted of 8 patients (mean age 32.5 years) with a normal urethra who were used as controls. All 16 patients underwent urethral pressure profilometry both at rest and with cough and hold maneuvers.

RESULTS

In group I, urethral pressure profilometry showed much lower mean maximal urethral pressures and maximal urethral closure pressures, as well as a much shorter mean functional profile length than in group 2 (48 and 39 cm H(2)O versus 75 and 65 cm H(2)O and 2.4 versus 4 cm, respectively, P <0.0003). On cough maneuver, intra-abdominal pressure changes were transmitted along the entire functional profile length in group 1 and only along its first part in group 2. The hold maneuver increased urethral pressure in 5 patients (65%) in group 1 and in all 8 patients (100%) in group 2.

CONCLUSIONS

Continence after anastomotic urethroplasty for post-traumatic posterior urethral strictures is maintained solely by the proximal urethral mechanism. Transmission of intra-abdominal pressure changes and contraction of pelvic floor musculature may augment urethral closure in these cases during stress conditions.

Urethral reconstruction of strictures resulting from treatment of benign prostatic hypertrophy and prostate cancer

Urethral strictures commonly result from treatments for prostate disease, such as transurethral resection, radical prostatectomy, and radiotherapy. Treating these strictures can be difficult: it may be complicated by previous irradiation, and endoscopy often fails. We review the risk factors for development of strictures resulting from the treatment of prostate disease and discuss the success rates of both endoscopic and open therapies.

Experimental evidence for a central nervous system site of action in the effect of alpha-adrenergic blockers on the external urinary sphincter

The present study was done to test the hypothesis that alpha-adrenoceptor blocking drugs (phentolamine and prazosin) could interfere with somatic control of the external sphincter through an action in the central nervous system. Stimulation of the hypogastric nerve in the chloralose-anesthetized cat caused a urethral constriction which could be antagonized by alpha-receptor blockers. However, the constriction produced by stimulation of the S1 or S2 ventral root was completely resistant to alpha blockade. The drugs therefore had the expected action against sympathetic stimulation of the urethra but had no peripheral effect on the somatic component. The central effect of these drugs was investigated by recording urethral perfusion pressure responses, or compound action potentials on the central cut end of the pudendal nerve, evoked by stimulation of the contralateral pudendal or pelvic nerve. The urethral constriction produced by stimulation of the central cut end of 1 pudendal nerve was antagonized by both prazosin and phentolamine. Action potentials evoked on the pudendal nerve by stimulation of the central cut end of the contralateral pudendal or pelvic nerve were substantially inhibited by prazosin. Phentolamine produced a more variable blockade of the pudendal-pudendal reflex. The results strongly indicate that these alpha-adrenoceptor antagonists and especially prazosin can influence pudendal nerve-dependent urethral responses through a central nervous system action and not through a peripheral mechanism.

Urethral stricture

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Urethral strictures secondary to pelvic injury in children

Surgical repair of a membranous urethral stricture is difficult because of the location and potential risks of incontinence, impotence and infertility. The treatment of 2 such strictures by the Badenoch pull-through urethroplasty is presented. The technique is described and its apparent advantages over other methods of repair are discussed.

The role of urethrography in urethral disease. Part II. Indications for transphincter urethroplasty in patients with primary bulbous strictures

We herein outline the radiological and clinical criteria that will aid the surgeon in deciding whether transphincter urethroplasty is required in patients whose primary stricture is in the proximal bulbous urethra. Sinc proximal bulbous urethral strictures are common the urologist frequently is called upon to make this important decision. The criteria described herein will help him to do so and, thus, avoid urethroplasty failure because of proximal stenosis in the membranous urethra. The concept of paradoxical dilatation of the membranous urethra on voiding urethrography also is described. Paradoxical dilatation means that in the presence of a primary obstructive bulbous urethral stricture the membranous urethra, although containing significant scar tissue, is dilated on the voiding study because of the distal obstruction. Relief of the bulbous urethral stricture alone may result in rapid contraction and stenosis of the previously dilated membranous urethra.

The one-stage island patch urethroplasty

Dartos-predicled scrotal skin island patch urethroplasties were performed in 72 patients and followed up for up to 7 years. Restenosis was seen at the site of the stricture in 5 cases and one developed a new meatal stenosis. There were no deaths. Hair-stones occurred in 4 patients and were removed endoscopically. One too-large pouch was trimmed. No patient was incontinent. More than one patch may be used for long or multiple strictures.

Transurethral external sphincterotomy sans external sphincter

Of 51 patients with detrusor-sphincter dyssynergia undergoing external urethral spincterotomy by transurethral resection, histological examination revealed no skeletal muscle in the resected tissue in six patients. The functional improvement which resulted in these cases despite this finding with an explanation for the same forms the topic of this paper.

Sympathetic dyssynergia in the region of the external sphincter: a possible source of lower urinary tract obstruction

Voiding cystourethrography demonstrated urethral constriction at the level of the external urinary sphincter in 10 patients with neurological dysfunctions. Ten mg. phentolamine mesylate intravenously alleviated this constriction, permitting better flow and reducing residual urine in 5 patients with a traumatic spinal injury, 2 with transverse myelitis and 1 who had had a cerebrovascular accident. Oral therapy with phenoxybenzamine hydrochloride, used in 7 of the 8 patients, reduced the post-void residual urine and produced improvement in hydronephrosis when present. These observations are consistent with the presence of a significant sympathetic component to obstruction at the region of the external sphincter in certain neurological disorders.

Two-stage urethroplasty for urethral stricture disease

Of 97 patients who underwent first-stage urethroplasty 23 per cent required at least 1 revision. Sixty-seven patients underwent second-stage reconstruction with a 90 per cent success rate. The various factors influencing the outcome of 2-stage urethroplasty procedures are analyzed critically.

Lower urinary tract pharmacology. I. Anatomic considerations

With this issue Dr. Bissada, Dr. Finkbeiner, and Dr. Welch introduce a series on uropharmacology, starting with the lower urinary tract. Since an understanding of the anatomy, neurophysiology, and basic pharmacology is necessary, Part I is a description of the functional anatomy of the lower urinary tract and the mechanisms of continence and voiding. Part II is a review of the differences between somatic and autonomic reflexes; the afferent and efferent innervation of lower urinary tract; the organization of pelvic ganglionic cells and the spinal and supraspinal control of lower urinary tract function. Subsequent articles will be on basic pharmacology of lower urinary tract and individual drug classes.