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Biomedical subjects

R C Rink

Publications and source records attributed to R C Rink.

At least 73 records · Page 4Linked to original sources
PubMed1995

Experimental assessment of small intestinal submucosa as a bladder wall substitute.

OBJECTIVES: This study determined the feasibility of promoting urinary bladder regeneration with porcine-derived small intestinal submucosa (SIS). METHODS: Twenty-two Sprague-Dawley rats underwent partial cystectomy with immediate bladder augmentation with SIS. Bladders were harvested for histologic evaluation at 2, 4, 8, 12, 24, and 48 weeks. RESULTS: Histologically at 2 weeks, there was infiltration of the graft material with viable host cells consisting of fibroblasts, macrophages, and blood vessels covered by complete mucosal urothelium comprised of transitional cells. During the next 10 weeks, collagen formation and maturation were noted, and by the end of 12 weeks, the SIS graft was comprised of a mature collagen matrix admixed with thinly scattered disorganized smooth muscle bundles and covered by normal urothelium. At 48 weeks, all three layers of the normal bladder (urothelium, smooth muscle, and serosa) were present and were grossly and microscopically indistinguishable from the normal rat urinary bladder. CONCLUSIONS: This study further supports the concept of bladder regeneration and suggests that SIS may be a viable material for bladder augmentations.

Animals↗
PubMed1995

Posterior urethral valves, pressure pop-offs and bladder function.

The pop-off mechanisms that sometimes occur with posterior urethral valves have well recognized implications for renal function, such that 1 or both kidneys can be protected from the deleterious effects of elevated bladder pressures. What has not been defined is the significance, if any, of pressure pop-offs to the developing bladder and ultimate bladder function. To answer this question we reviewed the records of 63 boys with posterior urethral valves. Eight boys who were not yet toilet trained had unevaluable bladder outcomes. Of the 55 remaining boys there was 1 or more pressure pop-off in 39 (71%), including massive (grade 5) reflux, massive reflux associated with ipsilateral renal dysplasia, a patent urachus, large diverticula and urinomas. Bladder outcomes were judged as favorable or unfavorable on the basis of urodynamic parameters and/or patient clinical status. A statistically significant positive correlation was found between the presence of a pop-off and a favorable outcome. Favorable characteristics were found in 34 of 39 bladders (87%) with pressure pop-offs. In contrast, only 9 of 16 bladders (55%) without pressure vents had favorable outcomes. In addition, 5 of the remaining 7 boys without pressure vents have required augmentation cystoplasty. A direct correlation between absolute number of pop-offs and favorable bladder outcome was also noted, further emphasizing this relationship. The presence of a pressure pop-off is a favorable prognostic sign for ultimate bladder function in boys with posterior urethral valves.

Adolescent↗
PubMed1995

Cloacal exstrophy: the neurological implications.

Congenital anomalies commonly accompany the abdominal wall defects of cloacal exstrophy with an incidence as high as 100% in some series. The urological literature cites an incidence of vertebral and/or spinal cord anomalies in 75% of cases. We reviewed the records of the 17 patients with cloacal exstrophy treated at our institution since 1978. Abnormalities of the vertebral column or spinal cord were identified in 16 patients, including 11 of 12 (92%) fully evaluated by myelography, computerized tomography or magnetic resonance imaging of the lumbosacral spinal cord. Nine patients had a lipomeningocele and 4 had a lipomyelocystocele. Spinal exploration, repair and cord untethering were done in 11 patients of whom 2 subsequently underwent reoperation for re-tethering the cord. A total of 15 patients is ambulatory although 5 require lower extremity braces. The incidence of spinal cord or vertebral anomalies in our patients with cloacal exstrophy approaches 100%, which is higher than commonly cited in the urological literature. We recommend magnetic resonance imaging of the spinal cord as part of the initial evaluation of newborns with cloacal exstrophy. Lifelong attention to the risk of spinal cord tethering can optimize neurological outcome in affected individuals.

Abnormalities, Multiple↗
PubMed1995

Stomach in combination with other intestinal segments in pediatric lower urinary tract reconstruction.

PURPOSE: We report the results of combining gastric and ileal segments in a small group of predominantly pediatric patients. MATERIALS AND METHODS: We retrospectively reviewed the records of 6 children and 1 adult who underwent lower urinary tract reconstruction using stomach and ileum, including 3 simultaneous and 4 staged procedures. Followup was 13 to 59 months. RESULTS: No patient had deterioration of renal function due to impaired upper tract drainage. One patient had an episode of hyponatremia during a gastrointestinal illness. The adult has the hematuria-dysuria syndrome and receives omeprazole. No ulceration developed in the 6 evaluable patients. CONCLUSIONS: The combined use of stomach and ileum has been effective in this small group of challenging patients. Long-term followup is mandatory.

Adolescent↗
PubMed1994

Long-term histopathological changes observed in rats subjected to augmentation cystoplasty.

Possible development of proliferative lesions in bladders subjected to augmentation cystoplasty is a matter of concern for many clinicians. We have previously reported on the development of bladder papillomas in 5 of 15 rats approximately 18 months after gastrocystoplasty. We now report a followup study designed to investigate histopathological changes occurring in rat bladders approximately 2 years after augmentation cystoplasty using various gastrointestinal segments. Prepubescent Long-Evans female rats were randomly divided into 4 groups and underwent either gastrocystoplasty, ileocystoplasty, colocystoplasty or a sham operation (controls). Animals were sacrificed 14 to 27 months (average 21.5) postoperatively and bladders were examined histologically. Metaplastic and/or hyperplastic changes were observed in the gastrointestinal patches or surrounding urothelium in all bladders having undergone augmentation cystoplasty. Tumors occurred on or adjacent to the lumenal surface of the augmented segment in 4 of 10, 3 of 11 and 2 of 11 rats that underwent gastrocystoplasty, ileocystoplasty or colocystoplasty, respectively. None of the tumors was observed to invade blood vessels, lymphatics or the underlying muscle layers. However, histological features of malignancy characterized by varying degrees of cellular pleomorphism occurred in some tumors. Control rats (10) had only minor changes related to reapposition of tissues and remnants of suture. Possible etiologies and the potential significance of these augmentation cystoplasty related proliferative lesions are discussed.

Animals↗
PubMed1994

The flip-flap technique to lengthen the urethra (Salle procedure) for treatment of neurogenic urinary incontinence.

We report the clinical results of a urethral lengthening procedure for neurogenic urinary incontinence. The urethra is lengthened by using a full thickness anterior bladder wall flap that is based at the urethra. This flap is approximated to a longitudinal strip of the trigonal mucosa and musculature. This neourethra is covered by urothelium creating a tunneled urethra, which creates a compressible flap valve mechanism that occludes with bladder filling. The ureters are reimplanted superior to the repair. Technical feasibility was first documented in the dog. Four myelomeningocele children with low urethral resistance and urinary incontinence refractory to medical management have undergone this procedure since July 1992. The 3 patients who have been followed for longer than 1 year are described. Two patients require concomitant bladder augmentation. Comparison of preoperative and postoperative urodynamics revealed increased urethral resistance. All 3 patients are clinically improved and dry on intermittent catheterization during the day. The patient without bladder augmentation has occasional nocturnal wetting. Since the posterior urethra and bladder wall remain intact without suture lines there have been no problems with catheterization. The upper tracts remain normal. We believe that this procedure is a helpful addition to the care of children with neuropathic incontinence. The technical aspects and results of this procedure are discussed in detail.

Child↗
PubMed1993

Urethral polyp presenting as interlabial mass in young girls.

We describe two young girls who presented with an interlabial mass. Histologic examination of each excised mass revealed a benign urethral polyp covered with transitional and squamous epithelium. Urethral polyps should be included in the differential diagnosis of an interlabial mass in young female patients.

Child, Preschool↗
PubMed1993

Bladder outlet reconstruction: fate of the silicone sheath.

The placement of a 1.5 cm. wide silicone sheath around a newly constructed urethra/bladder neck to ensure maintenance of repair length and to facilitate future placement of a sphincter cuff was reported by our institution in 1985. We present our long-term followup and new recommendations for use of the silicone sheath. A total of 15 silicone sheaths was placed between March 1981 and July 1984. Of the sheaths 14 were placed at the time of urinary reconstruction around the Young-Dees-Leadbetter bladder neck repair and 1 was placed after erosion of an artificial urinary sphincter cuff. Of the 15 sheaths 10 have eroded into the urethra and 4 sheaths remain in situ. Another sheath was replaced 2 years after its original insertion with an artificial urinary sphincter cuff. Mean time to erosion was 48.2 months, with a range of 2 to 108 months. Long-term followup of 10 patients revealed that 4 ultimately required ligation of the bladder neck and construction of continent stoma after erosion, 1 is dry after placement of a bulbar artificial urinary sphincter, 2 remain dry after removal of the eroded sheath alone, 2 required bladder neck revision to achieve continence after erosion and the most recent patient remains diverted with a suprapubic tube. All 4 patients with sheaths still remaining are dry without evidence of erosion (mean duration 116 months). These long-term results using a silicone wrap around a newly constructed bladder neck reveal an unacceptably high rate of erosion. Therefore, we no longer recommend or support the use of the silicone sheath in the manner we have described for bladder neck reconstruction.

Adolescent↗
PubMed1993

Seromuscular trough modification in construction of continent urinary stomas.

The creation of an effective flap-valve continent stoma requires use of supple, catheterizable conduit that is implanted in a submucosal bed having adequate backing. In some patients the backing that has been routinely used, colonic teniae or bladder detrusor for instance, is deficient or unavailable. As an alternative, the seromuscular layers of the recipient urinary reservoir can be simply reconfigured to provide the support required of a continent stoma. The technique has been effective in 4 patients and offers additional flexibility with challenging cases of continent urinary reconstruction.

Adolescent↗
PubMed1993

Appendicovesicostomy: a useful adjunct to continent reconstruction of the bladder.

Appendicovesicostomy is a useful adjunct to continent reconstruction of the bladder. During the last 3 years we have used this procedure in 14 children with difficult incontinence due to spina bifida (7), exstrophy/epispadias (5), imperforate anus (1) and urethral agenesis (1). In 4 patients in whom previous operations had failed to achieve continence the bladder neck was closed. In the remaining 10 children, all of whom had difficulty or discomfort catheterizing the native urethra, the bladder neck/urethra was preserved or reconstructed to serve as a vent for elevated bladder pressures. Continence was achieved in all 14 children with no complications related to the appendix. All children in whom the bladder neck/urethra was salvaged preferentially empty via the appendix and remain dry, except when the bladder is overly full.

Adolescent↗
PubMed1993

Lower urinary tract reconstruction using stomach and the artificial sphincter.

We implanted the artificial urinary sphincter at gastrocystoplasty in 13 male and 5 female patients. The diagnoses were classical bladder exstrophy (8 patients), myelodysplasia (8), cloacal exstrophy (1) and bilateral ectopic ureters (1). Mean patient age was 14.3 years (range 7 to 32.5). Six patients (5 with bladder exstrophy and 1 with clocal exstrophy) had failed bladder neck continence procedures, 3 myelodysplastic patients had failed artificial urinary sphincter placement, and 1 exstrophy patient had failed a Young-Dees bladder neck repair and artificial urinary sphincter placement. The sphincter cuff was placed around the reconstructed bladder neck in these patients, while in the remainder the artificial urinary sphincter was placed around the intact bladder neck. Mean followup was 20.3 months (range 1 to 5). Of the patients 16 (88%) are continent day and night, while 2 are wet. A total of 11 patients (61%) use Valsalva's maneuver alone for voiding and the remainder use Valsalva's maneuver and/or clean intermittent catheterization for bladder evacuation. Complications related to the artificial urinary sphincter were recurrent pump erosion requiring conversion to a Mitrofanoff continent stoma in 1 patient, and mechanical dysfunction requiring pump cuff and reservoir replacement in 3. There were no complications due to infection. Our report demonstrates that the combination of augmentation gastrocystoplasty and an artificial urinary sphincter leads to urinary continence and can allow for spontaneous urination. The rate of infectious complications is not increased when the 2 procedures are combined simultaneously.

Adolescent↗
PubMed1993

Improved results using a modification of the Young-Dees-Leadbetter bladder neck repair.

Forty-seven patients with primary total incontinence underwent bladder neck reconstruction (BNR) between 1978 and 1988. This included 31 patients with exstrophy/epispadias, 14 with myelomeningocele and 2 with caecoureteroceles. The patients were divided into 5 groups based on the type of BNR: Group 1--standard Young-Dees-Leadbetter (YDL) BNR; Group 2--YDL+Silastic sheath; Group 3--modified YDL; Group 4--Kropp BNR; Group 5--other BNRs. Group 1 included 18 patients with a 45% primary continence failure rate, a 44% reoperation rate and only a fair ability to void spontaneously after BNR. There were 11 patients in Group 3 with a 9% primary continence failure rate, a 27% reoperation rate and excellent post-operative emptying. None of the 3 patients in Group 4 was incontinent post-operatively, but they all required reoperation and had poor post-operative emptying. We feel that the modified YDL BNR provides better overall voiding and continence with less morbidity than the other bladder neck/urethral reconstructive procedures.

Adolescent↗
PubMed1992

Median raphe cysts of the genitalia.

We report 2 recent cases of midline cysts of the genitoperineal raphe in children, and discuss the embryogenesis, diagnosis and management. Congenital anomalies of an unclear etiology, median raphe cysts are probably more common than has been reported in the literature. Medical attention is usually sought for secondary infections or pain with intercourse. Awareness and prompt identification of these entities by urologists are essential for proper management when differentiation from other more formidable lesions, including urethral diverticula, becomes important. Simple surgical excision is effective in most cases.

Child↗
PubMed1990

Cloacal exstrophy reconstruction for urinary continence.

From 1978 to 1989 we treated 16 patients with cloacal exstrophy, including 8 who have been treated since birth. To achieve urinary continence bladder reconstruction was required in 12 patients, including 3 ileocystoplasties, 4 gastrocystoplasties and 5 gastric continent urinary reservoirs. All 12 patients underwent simultaneous bladder neck/urethral continence procedures. Of the 12 patients with completed reconstruction 10 were evaluable for continence. All 10 patients are dry for periods of 3 or more hours, and 5 are totally dry day and night. All but 1 patient are totally dependent on clean intermittent catheterization. Followup ranges from 2 to 66 months, and all except 1 patient have stable upper tract function. Patients with cloacal exstrophy can undergo reconstruction in a fashion to maintain urinary continence, and stomach is the ideal tissue for such reconstruction.

Adolescent↗
PubMed1990

Long term effects of gastrocystoplasty in rats.

Twenty prepubescent rats underwent microsurgical gastrocystoplasty by a technique which is described. An equal number of control rats had their bladders opened and closed. Rats were sacrificed at 16 to 18 months postoperatively. There were no differences in final weight, serum electrolytes, or renal function between the two groups. Prominent histopathologic changes of the bladder occurred in the gastrocystoplasty group. These changes included papillomas present in five of the 15 rats surviving long term. No significant changes occurred in the bladders of the control group of rats. Possible etiologies and the significance of the rats. Possible etiologies and the significance of the gastrocystoplasty related lesions are discussed.

Animals↗
PubMed1990

Physiology of lower urinary tract obstruction.

One of the major dilemmas facing pediatric urologists today is discerning obstruction in the dilated urinary tract. Apparently similar anatomic obstructions can result in very dissimilar consequences. The authors focus on the physiologic response of the bladder and upper tracts to infravesical obstruction. They caution against treatment focused merely on the obstruction, noting that the entire urinary tract must be addressed.

Animals↗
PubMed1989

Constant pressure perfusion: a method to determine obstruction in the upper urinary tract.

In an effort to define a more physiological method to determine obstruction in the upper urinary tract, the technique of constant pressure perfusion was studied in the canine and porcine models. In contrast to the constant flow technique of Whitaker, constant pressure perfusion is independent of upper tract compliance, uses low fixed pressures (7 to 12 cm. water) in the renal pelvis and measures flow rates from the upper tracts. In the canine and porcine models constant pressure perfusion demonstrated increased sensitivity and better discrimination between normal and partially obstructed systems relative to constant flow. Pressures in nonobstructed canine and porcine renal pelves are normally low (less than 8 cm. water) for flow rates into the bladder of 1 to 5 cc per minute. When using constant pressure perfusion in systems with partial distal ureteral obstruction, low or no flow is appreciated across the obstruction at renal pelvic pressures of 7 to 12 cm. water. By constant flow obstruction is defined in the same systems but only after renal pelvic pressures exceed 15 to 20 cm. water. We believe that there is clear clinical applicability.

Animals↗