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Biomedical subjects

C A Sheldon

Publications and source records attributed to C A Sheldon.

At least 37 records · Page 2Linked to original sources
PubMed1996

Doppler contrast sonography for detecting reduced perfusion in experimental ischemia of prepubertal rabbit testes.

RATIONALE AND OBJECTIVES: We examined whether the intravenous (IV) Doppler ultrasound contrast agent SHU 508 would improve the detection of reduced perfusion of rabbit testes when normal flow was otherwise difficult to detect. METHODS: Seventeen anesthetized prepubertal rabbits underwent random unilateral spermatic cord ligation and a contralateral sham operation. Immediate, blinded, and systematic color Doppler examination of each pair of testes was recorded before and after IV administration of 1 ml (300 mg) SHU 508, a gas-containing microparticle. Recorded examinations were reviewed by two pediatric radiologists who were unaware of experimental conditions and who graded intratesticular flow. RESULTS: For 34 pairs of observations (17 animals x 2 observers), intratesticular flow was absent in the sham-operated testes in 18 precontrast and two postcontrast images. The false-positive rate in this group decreased from 53% to 6%. This improvement in the detection of normal blood flow was statistically significant. The absence of flow in the ischemic testis was not significantly different before or after contrast agent administration. CONCLUSION: IV SHU 508 enhances color Doppler ultrasound detection of flow not otherwise evident in prepubertal rabbit testes. Doppler ultrasound contrast agents may be used in a setting of suspected torsion when routine Doppler sonography is indeterminate.

Age Factors↗
PubMed1996

Laparoscopically assisted testicular autotransplantation for management of the intraabdominal undescended testis.

PURPOSE: The intra-abdominal testis continues to present a considerable urological challenge and the approach to its management continues to evolve. We report our initial experience with laparoscopically assisted testicular autotransplantation. MATERIALS AND METHODS: An intra-abdominal testicle was identified laparoscopically in 5 patients who subsequently underwent testicular autotransplantation. RESULTS: The success rate was 100% and median operative time was 5 hours. All patients were discharged home the day after surgery with no complications and a good result. CONCLUSIONS: Because of success with this technique, this procedure offers significant advantages (decreased hospital stay and lower morbidity) than an open or 2-stage Fowler-Stephens approach.

Adolescent↗
PubMed1996

Acute testicular torsion: comparison of unenhanced and contrast-enhanced power Doppler US, color Doppler US, and radionuclide imaging.

PURPOSE: To compare the usefulness of conventional color Doppler ultrasound (US), unenhanced and contrast material-enhanced power Doppler US, and radionuclide imaging in a model of acute testicular torsion. MATERIALS AND METHODS: Twenty rabbits underwent unilateral 360 degree testis torsion and contralateral orchiopexy. Gray-scale, color Doppler, and unenhanced and contrast-enhanced power Doppler US were performed 4-6 hours later. The side of torsion was determined, and intratestis flow was graded. Within 2 hours of US, technetium-99m pertechnetate was intravenously administered, the rabbits were killed, and the testes excised for radionuclide imaging. RESULTS: Intratestis perfusion was detected in 85% of torsed testes at US and radionuclide imaging. The side of torsion was correctly diagnosed in 25% of cases with radionuclide imaging and in 60% of cases with US. Power Doppler US demonstrated significantly greater intratestis flow in pexed than in torsed testes. Although the numbers of correct diagnosis with the three US modalities were similar, flow grades within torsed and normal testes were significantly different. CONCLUSION: Perfusion to torsed and normal testes was demonstrated equally well with color Doppler US, power Doppler US, and radionuclide imaging. Doppler US better depicted differences in intratesticular flow between torsed and normal testes.

Acute Disease↗
PubMed1996

Urinary reconstruction (rather than diversion) for continence in difficult pediatric urologic disorders.

Surgical reconstruction of the pediatric urinary tract for purposes of restoration of function is a complex and highly successful undertaking that holds the potential of dramatically enhancing a child's health and quality of life. Unfortunately, such reconstruction may carry with it adverse sequelae that may complicate subsequent therapy and may be difficult to reverse completely. Urinary tract function has several components, each of which are essential to ensure maximal renal preservation, freedom from clinically significant infection, and continence. Several surgical alternatives exist for each component. Representative alternatives and surgical judgment with respect to their application are reviewed.

Child↗
PubMed1995

Testicular autotransplantation for the intra-abdominal testis.

Oftentimes patients with intra-abdominal testes require more than the standard procedure to accomplish orchiopexy. Division of the spermatic vessels has been one mainstay of operative approaches for the intra-abdominal testis since Fowler and Stephens (Congenital Malformations of Rectum, Anus, and Genitouriary Tracts, chapter 19, pp 306-320, 1963) provided an anatomically rational basis for this procedure. Silber and Kelly (J Urol, 115:452-454, 1976) first described using a microvascular anastomosis to bring extra blood supply to the testicle after mobilization of a high intra-abdominal testicle into the scrotum; however, this approach has not been adopted by many for a number of reasons. The microvascular skill and instrumentation required for a successful anastomosis are not universally available and there is a misconception that the procedure is a lengthy one (Bianchi, Br J Urol 56:521-524, 1984; Bogaert et al., Urology 42:182-188, 1993). We present our series for testicular autotransplantation used over a 17 year period with a greater than 95% success.

Abdomen↗
PubMed1995

Evaluation of acute scrotum in the emergency department.

A 2-year retrospective review of 238 cases of acute scrotal pain encountered in a children's hospital emergency department is presented. The incidences of testicular torsion, torsion of a testicular appendage, and epididymitis were 16%, 46%, and 35%, respectively. Testicular salvage was critically dependent on the interval between onset of pain and surgical intervention. No testis likely to have been viable at the time of presentation was "lost." The diagnostic error rate on first encounter was 7%, resulting in 10 negative scrotal explorations. With the exception of cases of far-advanced necrotic testes, both color Doppler ultrasound and radioisotope imaging were highly specific diagnostic modalities. Thirty-nine percent of the children with epididymitis who underwent investigation were found to have either structural or functional urinary tract abnormalities. Noninvasive urodynamic studies appear to be useful screening modalities in older children with epididymitis.

Acute Disease↗
PubMed1995

Gastrocystoplasty: technical and metabolic characteristics of the most versatile childhood bladder augmentation modality.

The authors report on 23 patients who underwent complex continent urinary reconstructions, made successful by the selection of gastrocystoplasty as the chosen augmentation modality. The mean patient age was 6.1 years, and the mean weight was 17.9 kg. The minimum follow-up period was 1.5 years. The bladder capacity increased from a preoperative mean of 77.8 +/- 52.2 (SD) mL to a postoperative mean of 303.5 +/- 117.4 mL (P < .000001). No adverse effects on renal function or serum electrolyte composition were encountered, and there were no instances of acidosis or alkalosis. Continence was achieved in 91% of patients. In two patients (0.9%), hematuria-dysuria developed; one case was extremely mild. The other occurred only during a period of severe oliguria and resolved after transplantation. Gastrointestinal complications were minimal. Five patients had end-stage renal disease at the time of reconstruction and have since had successful transplantation. Gastrocystoplasty is particularly applicable to the pediatric population because of its unique anatomic and metabolic characteristics, which bestow tremendous versatility.

Acidosis↗
PubMed1995

Comparison of color Doppler sonography and radionuclide imaging in different degrees of torsion in rabbit testes.

RATIONALE AND OBJECTIVES: We compared color Doppler sonography and radionuclide imaging in an animal model of variable torsion of the testes. METHODS: The testes of 19 rabbits with unilateral 0 degree (nontorsion), 180 degrees, 360 degrees, or 540 degrees torsion and contralateral nontorsion were evaluated by sonography serially over 24 hr. Color Doppler sonography and radionuclide imaging at 24 hr were compared and correlated with pathology in a subset of testes. RESULTS: Nontorsion (n = 16 testes) and 540 degrees torsion (n = 7 testes) were always correctly diagnosed at 24 hr by color Doppler sonography and radionuclide imaging. Torsion at 180 degrees (n = 2) was indistinguishable from nontorsion. With 360 degrees torsion (n = 6 testes), four testes had reduced or absent flow with color Doppler sonography, whereas only one testis was abnormal with radionuclide imaging. CONCLUSION: Nontorsion and extreme torsion of rabbit testes are well documented by radionuclide imaging and color Doppler sonography. Torsion at 360 degrees can result in variable flow alterations that are better detected by color Doppler sonography than by radionuclide imaging.

Animals↗
PubMed1995

Oxybutynin administration diminishes the high gastric muscular tone associated with bladder reconstruction.

Oxybutynin has a proved role in correcting uninhibited detrusor contractions in the intact and the bowel augmented bladder. Beneficial responses to oxybutynin have also been noted after gastrocystoplasty. It has been questioned whether this response reflects a selective effect on the bladder segment or whether there is an additional effect on the gastric patch musculature. We report a case of improved function of a previously poorly complaint gastric neobladder caused by oxybutynin, thereby demonstrating a direct action on gastric smooth muscle.

Female↗
PubMed1995

Relative microbial resistance of gastric, ileal and cecal bladder augmentation in the rat.

PURPOSE: Bladder resistance to bacterial infection after gastrocystoplasty, ileocystoplasty and cecocystoplasty was investigated in the rat. MATERIALS AND METHODS: Bladders were infected with Escherichia coli 6 to 13 months after augmentation and urine culture was obtained weekly for 3 months. RESULTS: No differences were observed in the number of infected animals within each group or electrolyte data among groups. The number of animals infected after surgery but before E. coli challenge was lowest in the gastrocystoplasty group. Bladder stones formed only in ileocystoplasty and cecocystoplasty groups. No group had a change in urinary pH. CONCLUSIONS: Gastrocystoplasty may be associated with a lower incidence of spontaneous infection and stone formation. An aggressive infection protocol may have masked differences in susceptibility to infection. Since urinary pH was unchanged after gastrocystoplasty, use of the rat may not be appropriate for augmentation studies.

Animals↗
PubMed1995

Testicular autotransplantation: a 17-year review of an effective approach to the management of the intra-abdominal testis.

PURPOSE: Patients with intra-abdominal testes represent a small but challenging group who require innovative therapy. We report our 17-year experience with testicular autotransplantation. MATERIALS AND METHODS: Testicular autotransplantation was performed in 23 patients with 27 intra-abdominal testes. RESULTS: The success rate was 96% and average operative time was 4.25 hours with 40 to 90 minutes for vascular anastomoses. A contralateral Fowler-Stephens procedure had previously failed in 3 cases. CONCLUSIONS: Since the variability of collateral blood supply in patients with high undescended testes may potentially compromise the Fowler-Stephens procedure, we believe that testicular autotransplantation should be strongly considered in such patients, particularly those with bilateral undescended testicles.

Adolescent↗
PubMed1995

Epididymitis in older boys: dysfunctional voiding as an etiology.

Although male infants and young boys with epididymitis have a high incidence of anatomical pathology, dysfunctional voiding is not a well established cause of epididymitis. In our series 36 boys with epididymitis underwent noninvasive urodynamic studies to determine whether a physiological defect could be assigned as an etiology. The 2 mechanisms proposed are similar to that in children with vesicoureteral reflux associated with dyssynergia or bladder instability and to a cause of recurrent urinary tract infection in children (the infrequent voider syndrome). Urinalysis and urine culture are recommended in all children with epididymitis and urethral swabs are obtained from those who are sexually active. We recommend renal/bladder ultrasound and voiding cystourethrography in all infants and young children with epididymitis. In the older child we advocate detailed questioning regarding voiding symptoms and the performance of noninvasive urodynamic studies.

Adolescent↗
PubMed1994

Management of multiple jejunoileal atresias with an intraluminal SILASTIC stent.

Multiple small bowel atresias present a unique challenge because maximum intestinal conservation is mandatory for survival. We recently treated a patient who had multiple atresias using a 7F SILASTIC catheter as an intraluminal stent. The catheter facilitated the completion of multiple primary anastomoses and served as a conduit for radiological evaluation and enteral feeding. The patient was a 1,860-g boy with 23 atresias of the jejunum and ileum. All stenotic segments were resected, and seven primary anastomoses were completed over the catheter. The distal 34 cm of bowel were exteriorized as a mucus fistula, with the catheter extending through to the level of the ileocecal valve. The proximal jejunal limb also was exteriorized. Eleven days later, contrast was instilled through the catheter and showed no leak or stricture. The catheter was then used for enteral nutrition and administration of the proximal jejunal effluent. Bowel continuity was reestablished after a tapering enteroplasty of the proximal jejunal limb. Parenteral nutrition was ultimately discontinued. Thirty-one months later, the patient no longer requires supplemental nutritional support. This case demonstrates the safety of multiple primary anastomoses over an exteriorized intraluminal stent. The catheter was useful in the radiological evaluation of the distal limb before it was used as an access route for enteral nutrition.

Diseases in Twins↗
PubMed1994

Renal transplantation into the dysfunctional bladder: the role of adjunctive bladder reconstruction.

A retrospective review of pediatric renal transplantation at 3 centers identified 9 patients who had undergone major bladder reconstruction. Seven patients underwent bladder augmentation (5 gastric, 1 colonic, 1 ureteral) and 2 received gastric neobladders. Six patients required Mitrofanoff neourethras. Patient survival was 100% with initial graft survival of 56% during a mean followup of 29.4 months. Eight patients (89%) are presently dialysis-free with functioning allografts and all 9 (100%) are continent of urine. We conclude that renal transplantation and reconstruction to ensure continence are justifiable in even the most anatomically compromised children with end stage renal disease. It is essential that the pediatric urologist should have an integral role in the management of such cases.

Adult↗
PubMed1994

A rabbit model of free bladder mucosal grafting in a damaged urethral bed.

Proximal and distal penile-urethral stomas were created in the rabbit and 1 to 3 months later a free bladder mucosal graft was placed in the damaged urethral bed. The graft adhered to a rapidly proliferating submucosa with active regeneration by post-transplantation day 5. All grafts were adherent and viable by days 10 to 14, during which time sham operated animals that had been stented only showed a degree of epithelial regeneration that was of variable quality and without submucosal proliferation. The graft may stimulate the subepithelial layer, and the most viable bladder mucosa may be associated with the most actively proliferating subepithelial layer, which is also the area of greatest neovascularity. Further studies may explain the apparent paradox of how a free bladder mucosal graft survives in a poorly vascularized, scarred urethral bed.

Animals↗
PubMed1994

Vaginal reconstruction: critical technical principles.

Childhood vaginal anomalies are frequently encountered, often in association with significant anorectal or urinary tract abnormalities. As a result, reconstruction poses a number of technical challenges. We maintain that the best results are achieved by single stage perineal reconstruction. The primary goal of achieving a functional and cosmetically adequate vagina must not be at the expense of the optimal repair of associated urinary and anorectal abnormalities. In addition, since these repairs are performed early in childhood, vaginal growth is an issue that further limits the choice of reconstructive technique. We present a series of successful vaginal reconstructions in complex cases and an outline of the principles of surgical care.

Abnormalities, Multiple↗
PubMed1994

Surgical implications of genitourinary tract anomalies in patients with imperforate anus.

Genitourinary anomalies in patients with imperforate anus are a frequent source of significant morbidity. We report a retrospective study of 64 genitourinary procedures performed on 23 patients. Renal, collecting system, bladder and perineal anomalies were encountered in 65%, 83%, 87% and 65% of these complex cases, respectively. A total of 70% of the patients required intermittent catheterization due to bladder dysfunction. Surgical alternatives, complications of management and functional outcomes are reviewed in detail. Genitourinary reconstruction is best undertaken as an integral part of imperforate anus reconstruction. Failure to do so results in the loss of surgical alternatives, unnecessary reoperative procedures and compromised outcomes.

Abnormalities, Multiple↗