Gracilis urethral myoplasty: preliminary experience using an autologous urinary sphincter for post-prostatectomy incontinence

Adynamic Graciloplasty With a Pedicled Gracilis Muscle Flap Wrapped Around Bulbar Urethra for Treatment of Male Acquired Urinary Incontinence

OBJECTIVE

To evaluate the efficacy of adynamic gracilis urethral myoplasty with a pedicled gracilis muscle flap wrapped around bulbar urethra for treatment of male acquired urinary incontinence.

PATIENTS AND METHODS

Twenty-four patients with acquired urinary incontinence (8 after radical prostatectomy, 7 after transurethral resection of the prostate, and 9 after posterior urethroplasty) were included in our study. Eighteen of these patients (75.0%) had mild to moderate urinary incontinence, and 6 (25.0%) had severe urinary incontinence. All patients received adynamic gracilis urethral myoplasty with a pedicled gracilis muscle flap wrapped around bulbar urethra and had a close follow-up.

RESULTS

The mean postoperative maximum urethral pressure after the gracilis muscle wrapped around bulbar urethra was significantly higher than that of the preoperative measurements (P <.05). After a mean follow-up of 31.5 months (6-64 months), 18 patients were cured, 4 patients improved, and 2 patients were considered failures. The total cure rate was 75.0% (18 of 24). Five out of 6 patients with severe incontinence did not have a great success.

CONCLUSION

A pedicled gracilis muscle flap wrapped around bulbar urethra can raise the urethral pressure. Adynamic graciloplasty with a pedicled gracilis muscle flap wrapped around bulbar urethra is a safe and effective surgical option in the treatment of male patients with mild to moderate incontinence, but is not suitable for severe incontinence.

Clinical factors that predict successful posterior urethral anastomosis with a gracilis muscle flap

Purpose

We evaluated the preoperative clinical factors that affect the surgical outcome of posterior urethral anastomosis (PUA) with a gracilis muscle flap (GMF) to determine which factors predict benefit from the use of the GMF.

Materials and Methods

This was a retrospective analysis of 49 patients who underwent a delayed PUA with a GMF. A successful clinical outcome was defined as achieving a peak urinary flow rate greater than 15 mL/s at 3 and 12 months postoperatively without evidence of stricture recurrence on a retrograde urethrogram or cystourethroscopy at 3 months postoperatively. Multiple clinical factors were evaluated by use of univariate and multivariate analyses.

Results

The outcome of 21 of 49 patients (42.9%) was deemed successful. The mean age of the 49 patients was 37.2±13.5 years and the mean follow-up duration was 43.4±28.0 months. The length of the urethral defect was significantly shorter in patients with a successful outcome than in patients with an unsuccessful outcome (p=0.010). The outcome differed significantly depending on whether the patients had a previously successful urethroplasty (p=0.036) or whether they had suffered a pelvic bone injury (p=0.012). Multivariate logistic regression analyses revealed that a previous urethroplasty was the only preoperative clinical factor that significantly affected the surgical outcome in PUA with a GMF (odds ratio, 0.218; 95% confidence interval, 0.050 to 0.947; p=0.042).

Conclusions

A history of previous urethroplasty is a preoperative clinical factor that significantly affects the surgical outcome in PUA with a GMF; the procedure is more likely to be successful in patients who have not previously undergone urethroplasty.

Electrically stimulated rectus abdominis muscle flap to achieve enterostomal continence: development of a functional canine model

BACKGROUND

Dynamic myoplasty has many clinical applications and has proven to be a versatile surgical procedure with great promise. This procedure has been used to achieve fecal/urinary continence, as in the dynamic graciloplasty, and to augment cardiac ventricular function, as is commonly seen with dynamic latissimus cardiomyoplasty. In the present study, the authors describe a functional innovative island flap sphincter created from the rectus abdominis muscle in a large-animal model to provide stomal continence for future clinical studies.

METHODS

The caudal region of the rectus abdominis muscle in eight mongrel canines (23 to 25 kg) was investigated through anatomical dissections during which the location of the neurovascular pedicles and the intersegmental muscle dimensions between the muscle inscriptions were noted. The rectus abdominis muscle was used to create functional dynamic stomal sphincters that were trained with subcutaneously implanted pulse stimulators.

RESULTS

The neurovascular pedicles were consistently found in similar locations along the posterior medial aspect of the caudal portion of the canine's rectus abdominis muscle. The vertical height of the deep inferior epigastric pedicle and caudal intercostal nerve muscular mean entry points were 6.75 +/- 1.89 cm and 7.44 +/- 0.86 cm, respectively. The mean caudal intersegmental muscle length of the rectus abdominis muscle used to create the sphincter was 9.69 +/- 1.81 cm.

CONCLUSIONS

The canine rectus abdominis muscle has reliable anatomical locations where the neurovascular pedicle may be found. This canine muscle may be used to create a continent island flap stomal sphincter. This large-animal sphincter model is versatile, durable, and easy to manipulate, with minimal morbidity to the animal.

Gracilis muscle neosphincter for treating urinary incontinence

The purpose of this study was to test the anatomical and functional feasibility of using a gracilis muscle free flap to create a urinary sphincter. Anatomical studies were performed in 12 human cadavers and short-term (n = 7) and long-term (n = 8) functional studies were performed in dogs. In the short-term functional studies, the left gracilis muscle was transferred into the pelvis and wrapped around the urethra and the right gracilis muscle was wrapped around a stent. A cuff electrode was placed on the muscle's nerve pedicle and used to stimulate the neosphincter while peak pressure, fatigue rate, and perfusion measurements were performed. In the long-term functional studies, intramuscular electrodes were inserted into the neosphincter to stimulate the flap. The flaps were wrapped around the urethra and dogs were followed for 16 weeks, during which time urodynamic measurements were performed. Our anatomical studies demonstrated that the gracilis muscle free flap could be transferred into the pelvis to create a urinary neosphincter. Our short-term functional study demonstrated that gracilis muscle free-flap function and perfusion were not compromised by transfer. In our long-term functional study, all neosphincters provided bladder outlet resistance pressures consistent with continence. Our anatomical, short-term, and long-term functional studies indicate that a gracilis muscle free-flap neosphincter is an effective procedure for treating urinary incontinence.

Muscular urinary sphincter: electrically stimulated myoplasty for functional sphincter reconstruction

PURPOSE

To reconstruct an electrically stimulated muscular urinary sphincter (MUS) using a tailored gracilis muscle free flap with intact nerve.

MATERIALS AND METHODS

Unilateral surgically tailored gracilis muscle free flaps were transferred into the pelvis in eight dogs, leaving the obturator nerve intact. The muscle's pedicle vessels were anastomosed to the inferior epigastric artery and vein in the pelvis and the muscle was wrapped around the bladder neck. Electrodes were inserted into the MUS and connected to a programmable pulse generator. After 8 weeks of training the MUS, the pulse generator was programmed to be "on" for 4 hours and "off' for 15 minutes in a continuous cycle. Urodynamic studies were performed periodically, and at the end of the experiment the MUS and proximal urethra were harvested for histology. Three control dogs had sham operations.

RESULTS

All MUS's functioned well following the procedure. Histology of the MUS/urethra complex showed no evidence of stricture. Except for one dog, all urethras were easily catheterized.

CONCLUSIONS

This electrically stimulated innervated free-flap MUS technique effectively increases bladder outlet resistance without producing urethral obstruction.