A magnetic device for increasing the urethral resistance to flow: an experimental study in female dogs.

OBJECTIVE: To test a new magnetic device for increasing the urethral resistance to flow in a dog model, and thus provide a potential mechanical device for the treatment of incontinence in women. MATERIALS AND METHODS: The study comprised 12 female mongrel dogs; three dogs were used to study the effect on urethral resistance of inserting a vaginal magnet (control experiment) and five were assessed in a urodynamic study. With the animals under general anaesthesia, the bladder and the urethra were exposed by a low midline incision. One magnet, embedded in a silicon layer, was placed on the anterior side of the urethra 3 cm distal to the bladder neck and fixed with a few sutures. To increase the urethral resistance as required, a second magnet was inserted into the vagina and the device activated. Urethral pressure profiles and leak-point pressures were recorded in the anaesthetized animals under resting conditions and after the urethra was compressed between the magnets. Recordings were also made after pharmacological blockade of the urethral musculature. In four additional dogs, chronic experiments were conducted to evaluate the effect of continuous compression of the urethra and the vaginal wall for 14 days. RESULTS: Urethral compression between the magnets resulted in a doubling of the maximal pressure in the proximal urethra and in a threefold increase of the leak-point pressure. After pharmacological denervation of the urethra the differences between the control pressures and those after activating the device were even greater, although not significantly so. After 2 weeks of continuous compression of the vaginal wall and the urethra between the magnets there was no detectable tissue damage. CONCLUSION: These results suggest that the magnetic device can efficiently increase urethral pressure and that prolonged compression caused no apparent damage to the urethra or vagina. It may therefore be a useful potential method of providing urinary continence in women.

A comparative study of the effects of a colorectal valve on the oro-anal transit time in patients with an augmented and valved rectum for urinary diversion.

OBJECTIVES: To evaluate the effect of the interposed colorectal valve on the flow of the proximal colonic contents to the rectum in patients with a valved urinary diversion to the rectum. PATIENTS AND METHODS: The oro-anal transit time (OATT) and segmental colonic transit time (SCTT) were estimated in two groups of 15 patients each (10 women and five men). In group 1, patients had a colorectal valve and in group 2 (control) they had no valve in the rectosigmoid area. The OATT and SCTT were evaluated using the 7-day method, whereby each patient swallowed 10 ring-shaped radio-opaque markers daily for 6 days, and a single abdominal radiograph was taken on day 7. The OATT and SCTT were then estimated as the number of retained markers divided by the daily dose of markers. RESULTS: The mean (sd) OATT was not significantly different (P=0.185), at 1.85 (1.21) days in group 1 and 2.49 (1.38) days in group 2. There were no sex differences in the values between the groups. The SCTT in the four areas of the colon again showed no significant differences within or between groups (P>0.05). CONCLUSION: Using a colorectal valve to functionally isolate the urinary rectal reservoir and thus reduce the high incidence of metabolic acidosis has no significant effect on intestinal transit times.

Radiology of the continent ileostomy reservoir: I. Method of examination and normal findings.

The aim of the present study is to describe the radiologic methods used to study continent ileostomy reservoirs and to depict the normal radiologic features and variations identified by these procedures. During an 8-year period, 408 double-contrast studies were performed in 261 patients. The present study comprises 170 examinations in 99 patients with normal findings. A high-density barium contrast medium and air were used. Modes variation in the size and shape of the reservoirs was observed. The mucosal pattern of the reservoirs resembled that of the ileum but the folds were slightly wider. The continence-providing valves were 3-5 cm long and had a diameter of 2.5-4.0 cm. The diameter of the afferent ileal segments was usually slightly larger than that of more proximal ileal segments, with an upper limit of approximately 4 cm. The efferent ileal segments generally had a straight course without widening or out-pouches. Retrograde barium double-contrast examination is a satisfactory method for the evaluation of continent ileostomy reservoirs. Here we define the range of normal variations of such reservoirs as seen on retrograde double-contrast radiologic examinations.

Radiology of the continent ileostomy reservoir: II. Findings in patients with late complications.

During an 8-year period, 238 barium double-contrast studies performed in 162 patients with continent ileostomy reservoirs who had signs and symptoms of late complications (malfunction of the valve, nonspecific inflammation of the mucosa, stenoses, hernias, and fistulas) showed radiologic abnormalities. The aim of the present study is to depict the radiologic findings in patients with late complications of continent ileostomy reservoirs. With radiologic examination, the correct diagnosis of valve malfunction was made in 96% of patients with surgically proven valve defects. We were able to differentiate between various types of valve dysfunction and complications related to the fixation of the reservoir to the abdominal wall. Inflammatory mucosal changes and fistulas of the reservoir and the afferent ileal segment were depicted with a high degree of accuracy. Barium double-contrast radiologic examination proved to be very valuable in the work-up of patients with dysfunction of continent ileostomy reservoirs. The method was of particular value in assessing the cause of valve dysfunction and in the appraisal of the afferent ileal segment.

Absorption of sodium and chloride in continent reservoirs for urine: comparison of ileal and colonic reservoirs.

The absorptive capacity of urinary reservoir mucosa was studied by measuring the fractions of 22sodium and 36chloride absorbed after instillation into reservoirs constructed from an ileal or a colonic segment. The absorption of 22sodium did not differ between the 2 reservoir types but absorption of 36chloride was greater in the colonic reservoirs. The levels of chloride in serum were significantly higher in patients with a colonic than in those with an ileal reservoir. In the ileal reservoirs the absorptive capacity was greater for 22sodium than for 36chloride.

Comparison between radiologic and endoscopic evaluation of the continent ileostomy reservoir.

The present study was performed to compare the results of radiologic examination and endoscopy in 156 patients with continent ileostomy reservoirs. Data from clinical follow-up and findings at revisional surgery were used for confirmation of diagnosis. One hundred and one patients had the clinical diagnosis nonspecific inflammation, 48 had symptoms of valve dysfunction, and 7 were studied because of suspected valve-shunting fistulas. For moderate and severe inflammation the findings on radiographs and at endoscopy were in accordance, whereas slight inflammation was more frequently reported by radiology than endoscopy. Radiology overdiagnosed slight inflammation. One disadvantage of endoscopy in patients with inflammation was that the afferent ileal segment could be reached in only 56%. By radiology 41 of 44 defective valves were identified (93%), whereas endoscopy disclosed only 24 defective valves (55%). The combined efforts of radiologic examination and endoscopy only managed to diagnose three of the seven patients with valve-shunting fistulas (two by radiologic and one by endoscopic examination). In conclusion, the retrograde double-contrast examination is a valuable complement in the assessment of patients with continent ileostomies and appears to be superior to endoscopy in the diagnosis of valve dysfunction and in depicting the afferent ileal segment.

[Evolution of urinary bladder substitution]. / Evolución de la sustitución de la vejiga urinaria.

The historical background to the currently used methods for continent bladder substitution is shortly outlined. The significance for the patient's quality of life of various methods for bladder reconstruction or urinary diversion is briefly discussed. The importance of reservoir configuration for achieving a high compliant urinary receptacle is pointed out. Factors affecting reabsorption of urinary constituents are stressed and the significance of an antireflux mechanism is discussed. Currently the majority of patients undergoing cystectomy for cancer or for other reasons can be offered bladder substitutes providing continence and easy emptying; that is, complete control over voiding. This can be achieved by orthotopic bladder reconstruction or by diverting the urine to the augmented and valved rectum or to the skin via a continent intestinal reservoir.

Ileostomy output of gas and feces before and after conversion from conventional to reservoir ileostomy.

In 28 patients who had previously had a proctocolectomy for ulcerative colitis, the ileostomy output of feces was determined before and after conversion to continent reservoir ileostomy, as was the output of gas in 20 of the patients. The median output of feces/24 hours collected in the hospital was 576 g before and 692 g after conversion (P less than 0.05); when collected at home the corresponding figures were 734 g and 740 g, respectively. In the majority of patients, the change in fecal ileostomy output after the conversion was not considerable, while in a few patients there was a marked increase. The fecal output was 24 percent (P less than 0.01) and 11 percent (P less than 0.01) larger at home than in hospital before and after conversion, respectively. The proportion dry weight of ileostomy discharge decreased after conversion (P less than 0.01). The median gas volume in the ileostomy output/24 hours was 1,664 ml before and 1,450 ml after conversion. The gas constituted 58 percent of the output and is significant with respect to the required reservoir capacity. Recording the emptying volumes and frequency in patients with reservoir ileostomy showed that, in general, patients with large output expand their reservoir capacity instead of increasing their emptying frequency.

Further experience with the modified rectal bladder (the augmented and valved rectum) for urine diversion.

Continent diversion with the modified rectal bladder was done in 83 patients and 65 are currently evaluable with followup ranging from 6 to 36 months. There was no postoperative mortality and the morbidity rate was acceptable. Renal function and configuration were maintained in most patients (91%). Dessusception of the colorectal valve was observed in 7.6% of the patients. Evidence was provided that this valve is effective in prevention of regurgitation of the rectal contents to the proximal colon. All patients were continent during the day. Enuresis was noted in 6 patients and all of them responded to imipramine hydrochloride therapy. The results support earlier observations that the procedure offers distinct advantages over ureterosigmoidostomy and the simple rectal bladder.

Further experience with the urethral Kock pouch.

In 185 men a urethral Kock pouch was constructed as a bladder substitute after radical cystectomy for cancer. A total of 117 patients was followed for a minimum of 1 year and is fully evaluable. Of the patients 108 (92%) are completely continent during the day, while 85 (73%) are dry at night. Also, 8 patients had an excellent response to imipramine hydrochloride. Stability or improvement in the configuration of the upper tract was noted in 210 renal units (90%). A total of 24 renal units showed evidence of deterioration due to reflux (16) and an anastomotic stricture (8). Stability of the antireflux nipple valve was ensured by creation of a window in the mesentery of the corresponding bowel segment and by anchoring the valve to the wall of the pouch by an additional row of staples. On the basis of this favorable outcome the procedure is recommended for male patients for whom cystectomy is indicated and in whom the urethra can be preserved.

Significance of the antireflux valve for upper urinary tract pressure. An experimental study in patients with urinary diversion via a continent ileal reservoir.

When bladder substitution is required, a low pressure receptacle and an antireflux valve with low resistance to flow is essential for preservation of the upper urinary tract. The aim of this study was to evaluate whether these criteria are attained in the continent ileal reservoir used for urinary diversion. The investigations were performed in six patients more than one year after supravesical urinary diversion via a continent ileal reservoir. The pressure was recorded simultaneously both in the afferent loop and in the reservoir during filling of the reservoir. There was a slow parallel increase in the basal pressure in the reservoir and the afferent loop. Pressure waves appeared sometimes simultaneously and sometimes in only one compartment at a time. Only during short periods of time did the pressure exceed 25 cm of water. The frequency of pressure waves increased with increased filling of the reservoir. The "total pressure" was larger in the reservoir than in the afferent loop. It is the antireflux valve which prevents pressure rises in the reservoir from being conveyed to the upper urinary tract. The resistance to urinary flow was moderate.

Pregnancy and delivery in patients with urinary diversion through the continent ileal reservoir.

The social and psychologic sequelae after external urinary diversion are known to be fewer in patients with urinary diversion through the continent ileal reservoir (Kock pouch) compared with those with diversion through the incontinent ileal conduit. Therefore, in young female patients treated surgically with urinary diversion through the continent ileal reservoir, a number of pregnancies can be expected. We report herein the results of four pregnancies in three women with this type of reservoir. All deliveries were vaginal. One patient showed urinary obstruction at the end of the pregnancy and delivery was induced. This particular infant was treated with phototherapy because of hyperbilirubinemia; the other three infants were mature. No damage to renal function was noted and revisional surgical treatment of the reservoir was not necessary in any. Consequently, pregnancy is not contraindicated after urinary diversion through the continent ileal reservoir (Koch pouch).

Bladder substitutes controlled by the anal sphincter: a comparison of the different absorption potentials.

A comparative study of the absorption potentials of the simple rectal bladder (10 patients), modified rectal bladder (20) and ureterosigmoidostomy (10) was done with intrarectal instillation of 22sodium. Results indicate that absorption is significantly greater among patients with ureterosigmoidostomy. The emptying patterns of ureterosigmoidostomy and the modified rectal bladder were also studied by ascending scintigraphy with 99mtechnetium. Evidence was provided that in cases with ureterosigmoidostomy the isotope is distributed throughout the entire colon. These studies proved the role of the colorectal valve in preventing reflux of urine from the rectum to the proximal colon. Consequently, the surface area of colonic mucosa exposed to urine is decreased and the rate of reabsorption is limited.

Decreased absorption of 22Na and 36Cl in ileal reservoirs after exposure to urine. An experimental study in patients with continent ileal reservoirs for urinary or fecal diversion.

After urinary diversion to intestinal segments, reabsorption of chloride, ammonium, and hydrogen ions occurs, sometimes leading to hyperchloremic acidosis. The mucosa of ileal reservoirs exposed to urine show substantial atrophy, indicating a loss of absorptive capacity. In ten patients with urinary diversion via a continent ileal reservoir, the absorption of [22Na] and [36Cl] was studied after instillation for 15 min into the reservoir of a test solution containing 50 kBq [22Na] and 50 kBq [36Cl]. The activity of the radionuclides was determined in serum samples after 60 and 180 min and the fractions absorbed were calculated. Absorption of the two radionuclides was also calculated by comparison of the activities in samples of the test solution taken before and 15 min after instillation into the reservoir. The same investigations were performed in seven patients with continent ileostomy reservoirs. The study demonstrated a decreased capacity to absorb [22Na] and [36Cl] across the mucosa of the reservoirs exposed to urine compared to the mucosa of those exposed to feces. Due to the transformation of the ileal mucosa after exposure to urine, the risk for development of metabolic disturbances should be minimal after urinary diversion to a continent ileal reservoir.

Long-term follow-up of patients with continent ileostomies.

Thirty-six patients were evaluated after having continent ileostomies for 16 to 20 years. Follow-up included clinical examination, response to a questionnaire, blood tests, and radiologic studies of the gallbladder. In addition, reservoir biopsies from 15 patients were examined. The patients were in excellent general health, all but one having gained weight postoperatively. There was no increased risk for gallstone formation or for urinary tract stone development. Although 11 of the 36 patients had reservoirs that were not provided with a valve, 92 percent of all patients were continent. Working capacity was normal in most patients and no harmful effects of the reservoir were revealed by morphologic or biochemical studies. In conclusion, no deleterious long-term effects were found as a result of the continent ileostomy.

Ileoanal anastomosis with interposition of the ileal 'Kock pouch'. Preliminary results.

For patients needing proctocolectomy, there are several alternatives available today for the previously dominating conventional ileostomy. Currently, the ileal pouch-anal anastomosis attracts major interest. Various reservoir procedures have been proposed, but the ideal reservoir design is still debated. The double-folded ileal reservoir (Kock pouch) has a large capacity, low pressure, and is expandable. It is successfully used for the construction of continent ileostomies, continent urostomies, and for replacing the urinary bladder by connecting the reservoir to the urethra. In view of these facts, it was decided to interpose the Kock pouch between the ileum and the anus after colectomy and mucosal proctectomy in a small number of patients, and to study and evaluate its merits in this position. Six consecutive patients formed the study group. Three months after ileostomy closure the stool frequency was 4 every 24-hours, range 3 to 5, and remained so during the follow-up period. All patients could sleep through the night without bowel movements or soiling. None of the patients used pads. The capacity of the reservoir increased from a mean of 100 ml preoperatively to 550 ml one year after ileostomy closure. The large reservoir capacity and the low pressure can explain the good functional results.

Renal function and upper urinary tract configuration following urinary diversion to a continent ileal reservoir (Kock pouch): a prospective 5 to 11-year followup after reservoir construction.

We followed 17 patients who underwent urinary diversion via a continent ileal reservoir (Kock pouch) with yearly examinations for 5 to 11 years postoperatively. The examinations involved control of renal function and configuration of the upper urinary tract. In 5 patients the upper urinary tract had become dilated during followup and in 2 of these renal scarring also had developed. All 5 patients had endured temporary outflow obstruction or reflux (stricture, overdistension of the reservoir or a defective antireflux valve). Of the patients 1 had a marked decrease in renal function before the outflow obstruction was corrected by an operation. Routine blood chemistry study was normal and hyperchloremic acidosis was not noted in any patient. After peroral loading of 6 patients with ammonium chloride significant excretion of titratable acid was found in the urine. Substitution with vitamin B12 was given to 6 patients due to subnormal values in 2 and borderline values in 4.