P. A. Dewan

Urothelial lined colocystoplasty in a sheep model.

Nineteen lambs underwent colocystoplasty using a segment of demucosalised sigmoid colon, and were compared to 14 control animals. Nine animals had a procedure which included the addition of the muscle patch to an autoaugmented bladder, and 10 had a clam cystoplasty with the denuded colon. Six months after the procedure, the average compliance value for the autoaugmentation colocystoplasty bladders was 5.7 +/- 1.7 ml/cm H2O, compared to 6.9 +/- 2.2 ml/cm H2O for the clam-demucosalised colocystoplasty group, and 11.0 +/- 4.8 ml/cm H2O for the control group. Whereas at 12 months the compliance values were 9.2 +/- 3.5, 10.7 +/- 5.1 and 9.1 +/- 3.7 ml/cm H2O for each of the groups, respectively. The sheep colonic muscle tolerated the demucosalisation procedure poorly, reflected in an inflamed, haemorrhagic colonic segment in the animals sacrificed within 1 month; this may have been the reason for the poor results, and explain why the autoaugmentation did not improve the outcome. Colonic mucosal regrowth occurred in 5, and was related to the demucosalisation technique.

Variable expression of the congenital obstructive posterior urethral membrane.

OBJECTIVESnTo assess the variability of membranous folds in the posterior urethra and their relationship to urethral obstruction.nnnMETHODSnEndoscopic video recordings of 19 boys with a membranous lesion in the posterior urethra were obtained over a 2.5-year period. Six had an endoscopy after a prenatal diagnosis of obstructive uropathy and 13 boys presented with either a urinary tract infection or hematuria.nnnRESULTSnYoungs type I and type III appearances were seen in all with an obstructive membrane, and those with a less obstructing membrane probably had incidental pathologic conditions.nnnCONCLUSIONSnThese observations support the thesis that the congenital attachment of the verumontanum to the anterior wall of the posterior urethra is the embryologic fore-runner to the congenital obstruction of the posterior urethra, and that there may be a variable degree of persistence of that attachment, which in some boys is not obstructive.

Autoaugmentation gastrocystoplasty and demucosalized gastrocystoplasty in a sheep model

OBJECTIVESnTo compare the normal sheep bladder at 6 and 12 months with bladders subjected to either an autoaugmentation gastrocystoplasty or a clam demucosalized gastrocystoplasty.nnnMETHODSnTwenty male lambs aged between 8 and 10 weeks had an autoaugmentation gastrocystoplasty in which de-epithelialized stomach muscle was added to an intact urothelium. The functional, radiologic, and histologic outcomes were compared with 11 animals who underwent a clam demucosalized gastrocystoplasty and 14 control animals. A total of 18 operated animals had a urodynamic study at 6 months and 9 at 12 months.nnnRESULTSnThe average bladder volume for the autoaugmentation gastrocystoplasty group at 12 months was greater than that of the control group (401 +/- 120 mL versus 205 +/- 77 mL). The demucosalized clam bladders had been less effectively enlarged (286 +/- 77 mL). The compliance values for autoaugmentation gastrocystoplasty animals were 14.7 +/- 11.3 mL/cm water (H2O) compared with 9.0 +/- 4.8 mL/cm H2O in the demucosalized gastrocystoplasty group, and 9.1 +/- 3.7 mL/cm H2O for the control animals.nnnCONCLUSIONSnThe addition of the autoaugmentation procedure improves the prospect of enlarging the normal sheep bladder when using demucosalized gastric muscle.

Plastic migration from implanted central venous access devices

BACKGROUND This is the first reported study of histologically confirmed migration from intravenous access devices in children. METHODS The capsules from around intravenous access devices were examined by light microscopy to determine the extent of the foreign body response; energy dispersive x ray analysis was performed to document the elemental content of the foreign material. RESULTS A fibroconnective tissue capsule was found around all the samples. Elemental silicon was found in six of 13 tissue samples, and a foreign body giant cell reaction was seen in three of these. CONCLUSIONS The pseudocapsule that surrounds an implanted vascular access device often has residual foreign material, including silicone.

Long-term histological response to intravenous Teflon and silicone in a rat model

Particle migration is one of the main concerns raised when implanted plastics are discussed, especially when used for the endoscopic treatment of vesicoureteric reflux in children. To study the histological response to migrated plastic material, we injected particulate plastics (Teflon and silicone) into the jugular vein of 21 Sprague-Dawley rats, 11 of which were killed at 12 months, 9 at 2 years, and 1 died at 18 months. The findings were similar for Teflon and silicone and unchanged after from 1 to 2 years. The plastic particles were seen outside pulmonary vessels, within aggregated multinucleate giant cells, surrounded by only small numbers of other types of inflammatory cells.

Ureterocystoplasty with renal preservation in young infants

To assess the outcome of ureterocystoplasty (UCP) with renal preservation in infants, three infants had a UCP with preservation of the ipsilateral kidney, including one who had a ureteropyeloplasty and one who had a UCP using a previously reimplanted ureter. All three had complication-free improvement in bladder volume and compliance. UCP thus produces an augmented bladder and can be performed as part of a transureteropyeloplasty and following ureteric reimplantation.

An in vitro study of silicone migration from intravenous fluid tubing

Migration of particulate matter from plastic tubing and solid plastic implants has been documented in a number of studies, including some with the use of cardiac bypass, haemodialysis, and pump-assisted intravenous infusions. In order to ascertain whether silicone embolisation occurs when children have an Ivac 560 pump-assisted IV infusion, we passed 180 ml of pumped fluid through a microfilter and compared the scanning electron micrographs of those filters with unused filters and with others through which a similar volume had been passed without using the pump. The particles on the filters were analysed for their elemental content using energy-dispersive X-ray analysis. In addition, the appearance of the silicone tubing used in the pump over 3 and 72 h was assessed and compared to that of flow-only and unused tubing. More particles were found on the microfilter when fluid had been delivered via the pump than on those through which nonpumped fluid had passed or that were unused. Elemental silicon-containing particles were only found on the filter when a pump had been attached to the IV line. The flow-only and unused tubing were found to have adherent particles on the inner surface that were not seen once the tubing had been used for 3 h in the Ivac 560 pump. Also, after 72 h use, the silicone tubing had a deformed inner layer. The clinical significance of these findings is yet to be determined, but it does appear that silicone embolisation occurs during pump-assisted infusions in children.

Historical trends in the management of bladder exstrophy

The history of bladder exstrophy dates back to 2,000 B.C., there being a reference to this congenital anomaly on an Assyrian tablet preserved in the British Museum. Although there are few references to “non-treatment” of this anomaly in newborns, or for that matter in older infants, there are now an increasing number of references to a wide variety of surgical procedures, and an attempt will be made to trace the historical sequence of many of these. The management of bladder exstrophy continues to advance with the recent advent of early closure, clean intermittent catheterisation, and continent stomas. However, the ability to make a prenatal diagnosis increases the challenge to obtain good cosmetic and functional results. Thus, efforts continue to be made to reliably produce continence, avoid morbidity from herniae, provide a normal umbilicus, and at the same time preserve renal function and achieve a favourable outcome for the genitalia.

CORRELATION OF THE ENDOSCOPIC APPEARANCE WITH CLINICAL OUTCOME FOR SUBMUCOUS POLYTEF PASTE INJECTION IN VESICO‐URETERIC REFLUX

The endoscopic injection of Polytef paste is now a well established method of treating vesico-ureteric reflux. In this study the video tapes of 64 treatments were independently reviewed to assess any predictors of failure. The visual appearance of the mound of paste was found to correlate with the clinical outcome, except when less than 0.2 mL of paste was used for smaller ureteric orifices, or when the ureteric orifice was large enough to admit the 9.3 FG cystoscope. In cases with a large ureteric orifice effective treatment was achieved without the neat crescent-on-a-mound appearance, provided a larger than average volume of paste was used. Meticulous placement of the needle was also shown to be important if success was to be ensured.

Further observations on histological changes at the ureteroileal junction in ileal conduits

Seventy-two ureteroileal anastomoses taken from ileal conduits removed from 62 patients were examined histologically to characterize the range of mucosal and stromal changes at these sites. All 72 demonstrated variable amounts of subepithelial chronic inflammation and fibrosis. Other histological features included: cystic spaces lined by transitional epithelium (N = 29; 40%; average diameter 1.2 mm); cystic spaces lined by mixed intestinal/transitional epithelium (N = 5; 7%; average diameter 0.77 mm); and cystically dilated intestinal glands (N = 21; 29%; average diameter 0.24 mm). The latter were associated with overgrowth by transitional epithelium, which had prevented mucus drainage. Twenty-one (29%) had mucus pools with no epithelial lining (average diameter 1.2 mm), and polypoidal protrusions into the lumen of the anastomosis were found containing mucus pools (N = 4; 6%; average diameter 1.4 mm), transitional-lined cysts (N = 5; 7%; average diameter 2.2 mm), and mixed intestinal/transitional-lined cysts (N = 2; 3%; average diameter 2.5 mm). Focal rupture of dilated intestinal glands with interstitial pooling of mucus was not uncommon, and marked dystrophic calcification was found in 1 case within a large collection of extracellular mucus. This series confirms that inflammation, fibrosis, and glandular overgrowth by transitional epithelium are common occurrences at ureteroileal anastomosis sites. Subsequent gland rupture may result in sizable accumulations of interstitial mucus, and rarely in marked dystrophic calcification.