Results of artificial sphincter in severe anal incontinence. Report of 14 consecutive implantations

PURPOSE AND METHODS: Fourteen AMS 800 (American Medical Systems, Minneapolis, MN) urinary artificial sphincters have been consecutively implanted in 13 patients with total incontinence for stool of various causes (traumatic or postoperative, 7; congenital, 3; neurologic, 2; idiopathic, 1). No proximal stoma was constructed but was already present in one patient before implantation. RESULTS: Sepsis occurred in two patients. Removal of sphincter and colostomy was necessary in three patients: one of these two had developed sepsis, one had perineal ulceration before activation of the sphincter in a severely scarred perineum, and one had severe pain in a radiation-injured anorectum. Sphincter-related failure occurred once by rupture of the cuff in a constipated woman after two years of satisfactory function. Reimplantation of a new cuff restored normal continence in this patient. After median follow-up of 20 (range, 4-60) months, nine of ten patients with a functioning sphincter were continent for stool, and five were also continent for gas. Failure occurred in one patient because the cuff was too large to occlude the anal canal. This patient is awaiting reimplantation. Four patients experienced easily controlled difficulties with evacuation of feces. Anal pressure with inflated cuff varied from 43 to 94 (mean, 58 +/- 12) cm H2O. CONCLUSION: These results show that an artificial sphincter has a role in the treatment of severe anal incontinence when local therapies are not applicable or have failed.     

Mayo Clinic long-term analysis of the functional durability of the AMS 800 artificial urinary sphincter: a review of 323 cases

PURPOSE: We determine the long-term durability of the AMS 800* artificial urinary sphincter in the correction of severe urinary incontinence, and evaluate mechanical versus nonmechanical failure and reoperation rates before (1983 to 1987) and after (1988 to present) the introduction of the narrow backing occlusive cuff design. MATERIALS AND METHODS: From January 1983 to October 1994 more than 400 patients received an AMS 800 artificial urinary sphincter placed by 1 surgeon and 323, mean age 60.4 years, met study requirements for review. Mean followup was 68.8 months (range 18 to 153). Only patients with a minimum of 18 months of followup were included in the study. Of the 313 men and 10 women in the study group sphincters were placed at the urethra in 272 and at the bladder neck in 51. All patients were followed from surgery to the date of sphincter failure. Etiology of the failures was recorded and divided into mechanical versus nonmechanical sphincters placed before and after the introduction of the narrow backing cuff. RESULTS: Overall, 58 of the 139 patients (42%) in the pre-narrow backing cuff group versus 31 of the 184 (17%) in the narrow backing cuff group required a first reoperation. Mechanical failure occurred in 29 cases (21%) with the pre-narrow backing and 14 (7.6%) with the narrow backing cuff. Nonmechanical failure developed in 24 cases (17%) with the pre-narrow backing and 17 (9%) with the narrow backing cuff. Ultimately 437 operations were required in the 323 patients, of whom 234 (72%) required no further surgical intervention at a mean followup of 68.8 months. CONCLUSIONS: Technological advances in the design and construction of the AMS 800 have dramatically decreased the reoperation and failure rates. These advances and improved surgical techniques provide an excellent long-term solution and increased continence in correctly selected patients with urinary incontinence.     

Inhibition of cytokine production and arachidonic acid metabolism by eucalyptol (1.8-cineole) in human blood monocytes in vitro

The authors implanted to a group of 10 patients incontinent after prostate surgery (on account of BPH and adenocarcinoma) an artificial AMS 800 sphincter. After a mean follow-up period of 29 months they evaluate based on a questionnaire the therapeutic effect and its influence on the patients quality of life as well as the adequacy of the approval procedure of indication on the part of the insurance company as it influences the quality of life. The effect of treatment and influence on quality of life is evaluated without exception very highly while the approval process is evaluated negatively. The authors draw attention to the risk of suicide in mentally otherwise sound subjects due to unsatisfactory solution of urinary incontinence. Correctly indicated treatment by an artificial sphincter can achieve very satisfactory results. The approval procedure must combine medical and rational aspects, it must be however revised, incl. the economic aspects of the system of health services.     

Urinary bladder incontinence after prostatectomy. Urodynamic evaluation and results of therapy

Forty-seven males referred due to postprostatectomy urinary incontinence (34 after transurethral resection of prostatic adenoma and 13 after open suprapubic adenomectomy) were retrospectively studied. Urodynamic evaluation identified 19 (40.4%) men with incontinence due solely to sphincter incompetence, and 19 (40.4%) men, in addition to sphincter incompetence, had urinary bladder dysfunction (unstable detrusor and/or reduced bladder compliance). Seven (14.8%) men had pure bladder dysfunction as the only cause of urinary incontinence. Two patients had normal urodynamic findings (N = 2; 4.2%). Men with urinary incontinence due only to sphincter incompetence were treated by insertion of artificial sphincter devices or condom catheter drainage (lack of artificial sphincters), while others were treated pharmacologically (imipramine, propantheline, oxybutynin or their combinations ... N = 25), or by augmentation cystoplasty using ileum after unsuccessful pharmacological treatment (N = 3). Out of 25 patients with pharmacological treatment, 21 were available for the final assessment of the treatment efficacy. Eleven (52.3%) patients were "socially continent" after the treatment. It is concluded that in the assessment of the cause of postprostatectomy urinary incontinence urodynamic evaluation is mandatory, and that the treatment should be based on the results of such studies. The role of bladder dysfunction as a cause of postsurgical urinary incontinence is again strongly emphasized.     

Identification of patients at increased risk for prolonged urinary retention following radioactive seed implantation of the prostate

PURPOSE: Urinary retention is a frequently reported complication following radioactive seed implantation of the prostate. If retention is refractory, a post-implant transurethral prostatic resection may ultimately be required to relieve obstruction, leading to an increased risk of urinary incontinence. In this series the incidence of prolonged urinary retention was determined, and the effect of pretreatment and treatment related factors was analyzed to identify high risk patients. MATERIALS AND METHODS: A total of 251 patients with organ confined prostate carcinoma underwent transperineal prostate seed implantation. Of the patients 114 were implanted with 103palladium (103Pd) and 137 with 125iodine seeds. Of the patients who were implanted with 103Pd 90 received 3 months of neoadjuvant hormonal therapy. All patients had International Prostate Symptom Scores (I-PSS) recorded before implantation to assess the degree of urinary symptoms. In the patients receiving neoadjuvant hormones prostate volumes and I-PSS were recorded before initiation of hormone treatment and 3 months later at the time of implant. RESULTS: Urinary retention developed in 14 patients requiring catheterization for more than 48 hours. Median time to onset was 1 day after implant. Of these patients 6 ultimately required transurethral prostatic resection to relieve urinary obstruction. No patient had urinary incontinence following implantation or transurethral prostatic resection. Multivariate analysis revealed that pretreatment I-PSS, and combined treatment with hormonal therapy and 103Pd predicted for the development of retention. Patients with I-PSS 20 or greater had a 29% risk, I-PSS 10 to 19, 11% risk and I-PSS less than 10, 2% risk of retention. Neither patient age, clinical stage, prostate specific antigen, Gleason score, use of 125I nor prostate volume was significant. A subgroup analysis of patients receiving hormonal therapy and 103Pd revealed that those with persistent urinary symptoms (I-PSS 10 or greater) following 3 months of hormonal therapy had the greatest risk of prolonged retention (37%). CONCLUSIONS: The overall risk of prolonged urinary retention following prostate implantation was low in our series. Using the I-PSS questionnaire, high risk patients can be identified before treatment. Patients with significant pretreatment urinary symptoms or persistent urinary symptoms following 3 months of hormonal therapy and then implantation with 103Pd have the greatest risk.     

Hpall endonuclease distinguishes between two species in the Anopheles funestus group

New surgical treatment modalities have been developed for patients with anal incontinence resulting from extensive sphincter destruction and in whom standard sphincter repair has failed. These new modalities include the transposition of striated skeletal muscles combined with implantation of neurostimulators, artificial sphincters based on the same principle as artificial urinary sphincters, and direct sacral nerve stimulation. In a few reported series muscle transposition in combination with neurostimulation has given a satisfactory continence in 50-70% of the patients. The same is true for the smaller series published on artificial anal sphincters, whereas the results of sacral nerve stimulation have thus far been reported in only a few patients. The selection of patients and the performance of these procedures should be limited to few specialist centres.     

Clinical, physiological, and radiological study of a new purpose-designed artificial bowel sphincter

BACKGROUND: Studies of the use of artificial urinary sphincters for faecal incontinence have led to refinement and adaptation of such sphincters to the anatomy of the anal region. We aimed to test this new device. METHODS: Six women, median age 53 (range 32-58) years, who were unsuitable for sphincter repair, had an artificial bowel sphincter implanted as a one-stage procedure without colostomy cover. Clinical assessment, physiological testing, and endosonography were done before and after the operation. Plain radiography, three-dimensional endosonography, and magnetic-resonance imaging were done after the operation, to define its anatomical location. RESULTS: Median follow-up was 10 (range 5-13) months and the device was functional in five patients. In one patient, the device was removed after ulceration through the skin. Of the patients with intact devices, Wexner incontinence scores improved from a median of 19 (18-20) of 20 before the operation, to 3 (0-6) of 20 after the operation. Median anal pressure at rest significantly increased from 60 (range 30-80) cm H2O to 110 (100-120) cm H2O. Functional anal-canal length varied after the operation from 3.3 cm to 3.8 cm. There was no significant change in the maximum tolerated volume of the rectum (140 [80-230] vs 100 [75-250] mL), or rectal compliance (2.9 [2.8-6.0] cm H2O/mL vs 3.5 [2.3-7.3] cm H2O/mL). All the imaging techniques accurately located the implant relative to the anal canal and pelvic floor in each patient. INTERPRETATION: The new artificial bowel sphincter provided a good functional result in five of the six patients, the surgical procedure was straightforward, and the maximum resting anal pressure rose without affecting rectal function. The ease of visualisation of such implants in situ should aid simple management of complications, should they arise.     

Stress urinary incontinence in women caused by severe sphincter hypotonia. Goebbel-Stoeckel intervention as alternative to artificial sphincter. Apropos of 26 cases treated between January 1985 and January 1994

Stress urinary incontinence with low urethral closure pressure and urethral mobility is often treated by artificial urinary sphincter. Our retrospective report in 19 patients evaluates the sling procedure as an alternative to the artificial urinary sphincter (7 patients). All patients had a preoperative clinical and urodynamic evaluation. 13 patients were continent (68.4%) in the sling procedure group and 5 in the sphincter group. Continence remained stable with a mean follow-up of 77 months (range: 39-110 months). 2 patients had urgency and none had dysuria. The sling procedure gave us the same results as sphincter with less morbidity.     

Low risk of urinary incontinence following prostate brachytherapy in patients with a prior transurethral prostate resection

PURPOSE: To review post implant morbidity in patients with prior transurethral prostate resection (TURP). METHODS AND MATERIALS: Nineteen patients with stage T1-T2 prostatic carcinoma and prior TURP were treated with I-125 or Pd-103 implantation from 1991 through 1994. Follow-up ranged from 1 to 6 years (median: 3 years). The time from TURP to implantation ranged from 2 months to 15 years (median: 3 years). RESULTS: Only one patient developed mild urinary stress incontinence, 6 months following his I-125 implant. The actuarial freedom from permanent urinary incontinence at 3 years after implantation was 94%. No patient required urethral dilatation for urethral stricture. Eleven patients were sexually potent prior to implantation. At 3 years after treatment, all patients had maintained potency. CONCLUSION: In our experience, there has been remarkably little adverse sequelae following I-125 or Pd-103 implantation in patients with a prior history of TURP.     

Anal and urinary incontinence after obstetric anal sphincter rupture]

The aim of the study was to assess the long term impact of obstetric anal sphincter rupture on the frequency of anal and urinary incontinence, and identify factors to predict patients at risk. In 94 consecutive women who had sustained an obstetric anal sphincter rupture, anal manometry, anal sphincter electromyography and pudendal nerve terminal motor latency at three months post partum was performed. A questionnaire regarding incontinence was sent between two to four years post partum. Forty-two percent of responders had anal incontinence, 32% had urinary and anal incontinence. Overall, 56% of the women had incontinence symptoms. The occurrence of anal incontinence was associated with pudendal nerve terminal motor latencies > 2.0 milliseconds and the occurrence of urinary incontinence was associated with the degree of rupture, the use of vacuum extraction and previous presence of urinary incontinence. Thirty-eight percent of the women with incontinence wanted treatment, but only a few had sought medical advice.     

Management of neurogenic fecal incontinence in myelodysplastic children by a modified continent appendiceal stoma and antegrade colonic enema

OBJECTIVES: Antegrade colonic enemas for neurogenic fecal incontinence via reverse reimplanted appendices (Mitrofanoff principle) have been primarily reported by Malone and coworkers in 1990. We used a modification of the described surgical technique and treated the first 10 patients with neurogenic fecal incontinence due to spina bifida. The surgical procedure and the results are reported. METHODS: Since November 1991, we have used a surgical procedure similar to the appendiceal continence mechanism in urinary diversion to establish a continent colonic cutaneous stoma for antegrade enemas in 10 myelodysplastic patients (4 females, 6 males; median age 13.2 years [range 6 to 26]) with severe neurogenic fecal incontinence. The average follow-up is now 26.4 months (range 12.5 to 50). All patients had neurogenic bladder dysfunction successfully managed by clean intermittent catheterization, anticholinergic drugs, or artificial sphincter implantation. The surgical technique for fecal incontinence included the partial orthotopic submucosal imbedding of the appendix into a cecal tenia and the fixation of the ileocecal region at the inner side of the abdominal wall after creation of an appendicocutaneous catheterizable stoma. RESULTS: All patients reached fecal continence for at least 38 hours (median 45.3) by using antegrade colonic enemas with 1.5% saline solution (n = 9) or GoLYTELY solution (n = 1), 0.5 to 1.5 L every 2 to 3 days. All other therapies (diet, oral medication, rectal purgative, or enema) to reach fecal continence had previously failed. There were only two complications seen at the follow-up. One boy with an artificial urinary sphincter presented with infection of the sphincter system, which led to explantation. Another boy presented 15 months after creation of the colonic appendiceal stoma with saline intoxication possibly due to a homemade saline solution. CONCLUSIONS: We conclude that the antegrade colonic enema via an orthotopic continent appendiceal stoma is a safe and highly effective treatment modality for fecal incontinence in patients with neurogenic bowel dysfunction if nonsurgical management has failed.     

One hundred cases of anal fissure treated with botulin toxin: early and long-term results

PURPOSE: Sphincterotomy still is considered the therapy of choice to eliminate sphincter spasm in the treatment of uncomplicated chronic anal fissure. The surgery is weighted with the possible surgical risk and the risk of subsequent fecal incontinence. This study reports the effect of botulin toxin injections within the first six months. PATIENTS AND METHODS: One hundred patients were treated (43 females; average age, 34.7 years). The injection of botulin toxin (2.5-5 units of Botox each) was done bilaterally to the fissure, thereby causing paresis of the sphincters for approximately three months. Patients were re-examined after one week and three and six months. RESULTS: Within the first week, 78 percent of patients were free of pain. In 82 percent of patients, complete healing of the fissure occurred within the first three months. Eight patients experienced relapses within the first six months of therapy, three of whom needed surgical intervention. The healing rate after six months was 79 percent. No healing occurred in 21 patients, and they had to undergo surgery. Transitory fecal incontinence resulted in seven cases. CONCLUSIONS: Injection of botulin toxin enables us to treat chronic, uncomplicated anal fissures with increased sphincter tone. It is well tolerated, can be administered on an outpatient basis, does not cause any lesion of the continence organ, and subsequently, does not lead to any permanent latent or apparent fecal incontinence.     

The use of polydimethylsiloxane in the treatment of incontinence after radical prostatectomy

OBJECTIVE: To report the results of transurethral submucosal injection therapy of polydimethylsiloxane (PDS) to treat incontinence after radical prostatectomy (RP). PATIENTS AND METHODS: Since 1993, about 80 retropubic RPs have been carried out at our institution each year. Severe post-operative incontinence occurred in six patients, with a mean duration of incontinence after RP of 28 months. The pre-operative evaluation consisted of cysto-urethroscopy and urodynamics. Because we have no experience with artificial sphincter implantation, transurethral injection therapy was used to treat the post-operative incontinence, using PDS (vulcanized silicone rubber particles). This material has a mean particle size of 188 microns, providing stability of the material at the injection site. The six patients with severe post-operative incontinence were treated using injection therapy with PDS. RESULTS: After a mean follow up of 15.5 months, five patients, who suffered from day and night incontinence and required at least five pads per day, were dry after injection therapy. One patient improved significantly but still required two pads during the day, but was continent during the night; three patients required a second injection. A mean of 7.5 mL of PDS was used per patient and the side-effects of therapy (dysuria and urinary retention) were minimal. CONCLUSION: Because PDS has excellent biocompatibility, few side-effects or complications, transurethral injection therapy using silicone particles is a justifiable procedure for treating incontinence after RP.     

Visuospatial neglect in normal subjects: altered spatial representations induced by a perceptual illusion

PURPOSE: All current bulking agents employed for treating stress urinary incontinence (SUI) have significant limitations due to various side effects, technical difficulties and inadequate long-term results. Implantable microballoons were therefore tested as a new therapeutic modality for female urinary incontinence. MATERIAL AND METHODS: The microballoons are implanted with a new system which consists of the self-detachable cross-linked silicone balloon, biocompatible filler material and a delivery system. Nineteen female patients (mean age 63.3 years) with SUI grade 1 or 2 were studied prospectively. Using the Blaivas-Olsson classification, 6 patients had stress incontinence type I, 4 had type II and 9 had type III. Three to seven balloons (mean 4.2) were implanted per patient. Patients were followed up with pad tests (g) and determination of leak point pressure (LPP; cm H2O) and maximal urethral closing pressure (Pura max; cm H2O) at 1, 3, 6, 12 and 18 months. RESULTS: The biocompatibility of the microballoons was excellent. No significant adverse events were associated with the procedure. With a mean follow-up of 14.4 months (range 10-18) 42.1% (8/19) of the women are dry. In the latter the pad test improved from a preoperative mean of 22.6 g (2-75) to 0 and the LPP increased from a preoperative mean of 38.5 cm H2O (25-60) to 80.5 cm H2O (68-106). 36.8% (7/19) of the patients showed significant improvement of their incontinence. In this group the pad test improved from a preoperative mean of 39.1 g (8-112) to 9.7 g (2-29) and LPP from a mean of 37.1 cm H2O (25-50) to 42.0 cm H2O (30-58). In 4 patients (21.05%) the technique failed. Seven of the 8 cured patients had type III incontinence; the eighth patient had type I incontinence. It failed in all patients with type II incontinence. CONCLUSION: The implantation of microballoons is a safe, well-tolerated and clinically effective modality for the treatment of type III SUI, i.e. intrinsic sphincter deficiency.     

Our experience with pubovaginal slings in patients with stress urinary incontinence

PURPOSE: Pubovaginal slings successfully treat stress urinary incontinence in women with intrinsic sphincter deficiency. Because of its durability, it has been an attractive procedure in select patients with urethral hypermobility. We examine our experience with pubovaginal sling. MATERIALS AND METHODS: A total of 150 patients were evaluated for pelvic prolapse and urinary incontinence. An abdominal leak point pressure was determined in all patients. Of patients with type II stress urinary incontinence, 36 patients (80%) underwent additional gynecological procedures at the time of the pubovaginal sling, compared to 29% with intrinsic sphincter deficiency and 33% with coexisting urethral hypermobility and intrinsic sphincter deficiency. RESULTS: The overall cure rate was 93% with a mean followup of 22 months. At 1 week postoperatively spontaneous voiding was accomplished by 56% of the patients with urethral hypermobility and 57% with intrinsic sphincter deficiency. Only 2.8% of patients required surgical therapy for prolonged urinary retention. De novo urgency/urge incontinence occurred in 19% of women with a 3% incidence of persistent urge incontinence. CONCLUSIONS: Pubovaginal slings are effective and durable. Voiding dysfunction is uncommon and is temporary in most patients.     

Signs of vagal reinnervation 4 years after heart transplantation in spectra of heart rate variability

OBJECTIVES: Transurethral injection of glutaraldehyde cross-linked bovine collagen has recently been advocated as a potentially useful treatment modality for management of urinary incontinence. The reported clinical experience with urethral collagen injection in adult males has been limited. METHODS: This study summarizes the current literature and reviews the clinical results of collagen injection in a group of 25 men with incontinence after either transurethral or radical prostatectomy. RESULTS: The overall results in this series were disappointing. Only 2 patients (8%) achieved significant improvement with this treatment. Eight patients (32%) experienced minimal improvement in symptoms, and 15 (60%) remained incontinent with no improvement in symptoms after collagen injection. The number of injection procedures and volume of collagen material implanted did not correlate with clinical outcome. Five patients (20%) have subsequently required placement of an artificial urinary sphincter to control their incontinence. CONCLUSIONS: We conclude that transurethral injection of glutaraldehyde cross-linked bovine collagen has a limited role in the management of urinary incontinence in adult men after prostatectomy.     

Collagen injections for intrinsic sphincter deficiency in the neuropathic urethra

Twelve subjects experiencing stress urinary incontinence caused by spinal injury or myelomeningocele were treated by periurethral injection of a bulking agent, glutaraldehyde cross-linked (GAX) collagen. Of the 11 subjects who completed the program, seven were either cured or improved and four were only slightly improved or no better following injection. The valsalva (abdominal) leak point pressure (LPP) rose an average of 57 cm H2O (pre-treatment mean of 60 cm H2O versus post-treatment mean of 117 cm H2O) and none of the patients experienced significant complications during the mean follow-up period of 24 months. Every subject injected was able to maintain an intermittent catheterization program after treatment. These data support the use of GAX collagen as an alternative or adjunct therapy to pharmacotherapy, surgical reconstruction or implantation of a prosthesis in the management of stress urinary incontinence in the neuropathic urethra.     

Catheter-free same day surgery transurethral resection of the prostate

PURPOSE: Transurethral resection of the prostate using electrocautery has long been the standard method of management of lower urinary tract obstructive symptoms. While there has been a trend towards reduced catheterization time following transurethral prostatic resection, this study outlines the methods and results of transurethral prostatic resection performed in the day surgery setting. MATERIALS AND METHODS: The study was performed at a free-standing licensed day surgical hospital serving a patient population of more than 150,000. A total of 58 patients of a mean age of 68.77 years (range 49 to 87) underwent same day conventional transurethral prostatic resection. Of the procedures 39 (67%) were performed with spinal and the remainder with general anesthesia. RESULTS: Mean overall duration of catheterization was 6.54 hours. Of the 48 patients (82.76%) undergoing single catheterization mean duration was 5.59 hours. Mean total duration of catheterization for 10 patients (17.24%) who required reinsertion of a catheter was 11.09 hours. Duration of catheterization was 7.69 hours for patients treated with spinal and 3.86 for those treated with general anesthesia. Repeat catheterization was required in 10 patients and was due to urethral discomfort in initiating micturition in 8. Postoperative urinary tract infections occurred in 2 patients. No patient was readmitted to the hospital for retention of urine but 1 was admitted to a private hospital for management of postoperative fever and 1 for monitoring of tachycardia. CONCLUSIONS: Conventional transurethral resection of the prostate can be effectively managed in the day surgery setting with minimal morbidity. There are significant advantages in reduction of catheterization time and duration of hospital stay, and the procedure compares favorably with new modalities.     

Effect of neonatal surfactant therapy on lung function at school age in children born very preterm

BACKGROUND: Involuntary detrusor contractions often cause irritative symptoms such as urgency and incontinence. A dog model for acutely induced variable bladder outlet resistance was developed to investigate the possible role of prostatic afferent nerve fibers in the development and maintenance of detrusor instability. METHODS: Fifty-eight mongrel dogs (weight range 19.5-36.5 kg) were divided into five groups: group I (n = 11) had surgically induced bladder outlet obstruction. Group II (n = 14) had urinary obstruction and bilateral sectioning of the lowest branches of the pelvic plexus supplying the prostate. Group III (n = 10) had prostate denervation only. Groups IV (n = 10) and V (n = 13) were sham-operated and controls, respectively. In the obstructed groups (I and II), an artificial urinary sphincter (length 4.5-6.0 cm) was placed around the bladder neck and connected to a reservoir placed subcutaneously to allow postoperative adjustments of urinary resistance. All dogs were evaluated at baseline and postoperatively at 1, 3, and 6 months with uroflowmetry, postvoid residual urine volume, cystometry as well as serum creatinine, and urinalysis. RESULTS: Occurrences of detrusor instability were not associated with prostatic denervation input. The mean peak flow rates decreased significantly in the obstructed groups at all follow-ups, but did not change significantly in the nonobstructed groups. Postoperatively, the mean maximum bladder capacity was significantly decreased for groups I and II only. However, a significant correlation between maximum bladder capacity and maximum detrusor pressure could not be detected at any time point in any of the groups. Mean postvoid residual urine volume varied considerably in all groups over time. Creation of a urinary model of infravesical obstruction was associated with considerable problems. CONCLUSIONS: In our dog model of bladder outlet obstruction, prostatic sensory nerve fibers appear not to be involved in detrusor instability. Surgical induction of a constant model of bladder outlet obstruction was difficult even in a large animal. The observations from the present study raise questions about the validity of obstructive urinary animal models.     

Assessment of a novel implantable artificial anal sphincter

PURPOSE: The aim of the study was to test a new implantable artificial anal sphincter in the porcine model. METHOD: The artificial sphincter, which includes an inflatable expander that compresses and flattens the bowel against a pillow, was implanted in 16 animals and studied for periods of up to 20 weeks. The anal sphincters were destroyed, and the efficacy of the device in rendering the animals continent was studied. RESULTS: Of the 11 animals in which the artificial sphincter was regularly closed, 8 completed the study and were continent during 85 percent of activation times. There was no evidence of ischemic injury. Major complications were related only to failure of the control pumps of the device. CONCLUSION: This study suggests that this neosphincter produces fecal continence without intestinal ischemia. At present reliability is limited only by the performance of the pump.