Mohamed Dawaba

Comprehensive analysis of tubularized incised-plate urethroplasty in primary and re-operative hypospadias.

To retrospectively review our experience of the tubularized incised‐plate (TIP) urethroplasty over the last 4 years.

Treatment of Urethral Defects: Skin, Buccal or Bladder Mucosa, Tube or Patch? An Experimental Study in Dogs

PURPOSE We studied 3 graft materials and 2 urethroplasty techniques in 24 adult male mongrel dogs. MATERIALS AND METHODS The animals were divided into 2 equal groups. In group 1 a 4 cm. segment of perineal urethra was excised and tubed urethroplasty was performed using free full-thickness skin, buccal and bladder mucosa grafts in 4 dogs each. In group 2 a 4 cm. urethral strip was excised and onlay urethroplasty was performed using the same graft materials in 4 dogs each. Retrograde urethrography was done and the animals were sacrificed at week 12. Autopsy specimens were calibrated with a 10Fr catheter. Hematoxylin and eosin stained sections were examined. Massons trichrome stain was used to determine the extent of fibrosis. RESULTS Urethral stricture was diagnosed by radiology and confirmed by calibration in 8 of the 12 dogs (66%) in group 1 but in only 1 of the 12 (8%) in group 2 (p <0.004). Buccal mucosa grafts were associated with the lowest stricture rate of 12%, followed by 37% for bladder mucosa and 62% for skin (p <0.2). There was no difference in neovascularization among the 3 grafts. Graft shrinkage was less than 10% for buccal mucosa compared with 20% to 40% for skin and bladder mucosa. The shrinkage rate was similar for the onlay and tube techniques. The intensity of chronic inflammation and fibrosis was highest in the skin grafts. Circumferential fibrosis was noted in association with tubed urethroplasty but not with the onlay technique. CONCLUSIONS The theoretical advantages of buccal mucosal grafts were pathologically demonstrated. When possible, grafts should be used as an onlay rather than as a complete tube.

Posterior Urethral Valves: Multivariate Analysis of Factors Affecting the Final Renal Outcome

PURPOSE Posterior urethral valves represent the most common obstructive uropathy in children with a broad spectrum of clinical severity. We evaluated prognostic variables affecting the outcome of renal function in such children. MATERIALS AND METHODS Between 1987 and 2004, 120 patients with a mean age of 2 years with posterior urethral valves were treated initially with valve ablation at our center. We studied certain parameters, including age at presentation, serum creatinine (initial and nadir), initial creatinine clearance, renal ultrasound findings (hydronephrosis and renal parenchymal echogenicity), vesicoureteral reflux on initial voiding cystourethrogram, bladder dysfunction and popoff mechanisms such as the syndrome of large vesical diverticulum, urinoma and ascites. Long-term renal outcome was assessed. RESULTS Followup was 2 to 16 years (median 3.6). Renal insufficiency developed at the end of followup in 44 patients (36.5%). Serum creatinine at hospital admission, nadir serum creatinine, initial creatinine clearance and renal parenchymal echogenicity were significant predictors of the final renal outcome (p < 0.05). Patient age at diagnosis (2 or less vs greater than 2 years), upper tract dilatation, the presence or absence of vesicoureteral reflux, popoff mechanisms and bladder dysfunction had no significant impact on future renal function. On multivariate analysis nadir serum creatinine was the only independent prognostic factor. CONCLUSIONS Our data confirm the high prognostic value of nadir creatinine after primary valve ablation. Also, initial serum creatinine, creatinine clearance and renal parenchymal echogenicity on initial renal ultrasound correlate significantly with long-term renal function in children with posterior urethral valves.

LONG-TERM OUTCOME ANALYSIS OF LOW PRESSURE RECTAL RESERVOIRS IN 33 CHILDREN WITH BLADDER EXSTROPHY

PURPOSE The augmented valved rectum and double folded rectosigmoid bladder represent 2 modifications of ureterosigmoidostomy. Both procedures improve continence by lowering the reservoir pressure. We present the outcome of these techniques on the upper urinary tract, continence, metabolic profile, linear growth and bone density. MATERIALS AND METHODS Between March 1987 and May 1997, 22 boys and 11 girls with bladder exstrophy underwent urinary diversion to a low pressure rectal reservoir. Patient age at surgery ranged from 2 to 13 years (mean 5.4). The augmented valved rectum technique was used in 18 cases and the double folded rectosigmoid bladder method was used in 15. Serial followup ultrasounds were obtained and voiding proctography was performed 1 year postoperatively in all patients. Supine height was measured at last followup in all cases. Serum electrolytes, arterial blood gases, the results of which were plotted on an acid base nomogram, and bone density using dual energy x-ray absorptiometry were measured in all patients. Prophylactic alkalization was administered to all patients. RESULTS Mean followup is 66 months (range 24 to 148). All patients are continent during the daytime with an emptying frequency of 3 to 5 times, and all are continent at night. No patient experienced pyelonephritis or clinical acidosis. The upper urinary tract was either improved or stabilized in 64 of 66 renal units. No patient had reflux to the upper urinary tract. All patients had normal serum creatinine, sodium, potassium, calcium and phosphorus. Hyperchloremia was noted in 19 of the 33 patients (57%), and arterial blood gases showed subclinical metabolic acidosis in 18 (55%). Supine height measurements at last followup revealed that 19 of the 33 patients (57%) had decreased linear growth (below 3rd percentile). All patients had significant reduction in bone density, and mean for age corrected bone density was 70% (standard deviation 10.9%). Both groups (augmented valved rectum and double folded rectosigmoid bladder) were comparable in regard to age, sex and followup duration. There was no statistically significant difference between the groups in any parameter measured. CONCLUSIONS The augmented valved rectum and double folded rectosigmoid bladder provide preservation of the upper urinary tract with excellent continence rates. However, prophylactic alkalization and functional isolation of the reservoir do not prevent the long-term metabolic consequences. Subclinical metabolic acidosis and decreased linear growth are to be anticipated in more than 50% of patients. Moreover, significant bone demineralization is to be expected in all of these patients.

Surgical complications of posterior urethral valve ablation: 20 years experience

PURPOSE The aim of the study was to report the surgical complications that may occur during or after primary ablation of posterior urethral valve (PUV) in a large number of cases treated using different modalities. MATERIALS AND METHODS We retrospectively reviewed a database of 291 patients with PUV treated by primary valve ablation from 2 separate centers between 1987 and 2006. Primary valve ablation was performed in all patients regardless of serum creatinine level or upper tract configuration. A hot loop resectoscope was used in 122 patients, cold knife urethrotome in 108, a hook diathermy electrode in 18, a diathermy coagulation bugbee electrode in 20, whereas stripping using a Fogarty catheter was performed in 23. RESULTS The follow-up duration ranged from 1.5 to 20 years (median, 6.5). Early postoperative complications occurred in 22 patients (7.5%). The most common complication was urinary retention in 16 patients (5.5%). Urinary extravasations occurred in 3 cases, significant hematuria from urethral bleeding occurred in 2, and obstructive anuria developed in 1 patient. Most of cases were treated conservatively. Urethral strictures developed in 6 patients (2%) mainly after endoscopic loop resection (4/6). All were treated by visual internal urethrotomy and urethral dilatation with successful results without the need of open urethroplasty. CONCLUSIONS Primary valve ablation seems to be safe and is associated with low rate of postoperative complications. All the complications could be treated conservatively. Urethral stricture may occur after valve ablation in a minority of cases and can be successfully treated endoscopically. Loop resection is associated with more strictures.

The modified rectal bladder in children: long-term follow-up.

SummaryThe criteria for evaluation of urinary diversion procedures in children must be strict since their life expectancy is long. Our experience with the modified rectal bladder in children with considerable follow-up periods is reported herein. All patients were continent by day and night. Urography studies revealed a normal upper tract in all cases. Three early complications were encountered among patients who had a submucous tunnel reimplantation. Reflux to the proximal colon or the kidneys was not demonstrated. The metabolic status and growth-rate patterns of these patients were within normal limits without alkaline therapy. All urine samples aspirated from the renal pelves were sterile. We conclude that a modified rectal bladder with a second ileal intussusception valve is the operation of choice whenever urinary diversion in children is indicated.

Urethral Controlled Bladder Substitution: A Comparison Between Parks S Pouch and Hemi-Kock Pouch

To study the effect of the configuration of ileal reservoirs on the urodynamic features, 12 S bladders and 12 Kock pouches were compared. Volume capacity and pressure characteristics were studied 6 months postoperatively. The mean capacity of the reservoirs was 500 +/- 83 ml. for the S bladder and 536 +/- 56 ml. for the Kock pouch. The amplitudes of phasic contractions at 50%, 80% and 100% capacity were similar in both groups. However, the frequency of these contractions was higher in the S bladder. The intraluminal pressure at full capacity was 31 +/- 15 cm. water for the S bladder and 39 +/- 20 cm. water for the Kock pouch. The similar urodynamic features of the S and Kock pouches indicate their ultimate expansion into reservoirs of close physical characteristics and urodynamic behavior.

Long-term functional and morphological outcome after pyeloplasty for huge renal pelvis

Study Type – Therapy (case series)

Tunica albuginea acellular matrix graft for treatment of Peyronie's disease. An experimental study in dogs

Objective: To study the value of an acellular matrix graft of the tunica albuginea for reconstruction of the penis in cases of severe Peyronies disease. Material and Methods: In nine mongrel dogs, an acellular matrix graft of the tunica albuginea was used to cover a 30×10 mm 2 tunical defect. Equal numbers of animals were sacrificed at 1, 3 and 6 months after surgery. Before death, an erection was induced by means of papaverine injection and cavernosography was performed. After death the penis was prepared for histopathological study. Results: All animals survived the surgery and none developed haematoma, wound infections or dehiscence. All dogs developed a straight, rigid erection. Cavernosography showed patent corpora cavernosa in all animals. The papaverine injection and cavernosographic results did not change over time. Inspection of the graft site and measurement of its length and width showed healing with no contracture. Histologically, the regenerated matrix appeared thicker than the neighbouring tunica albuginea in the 1‐month group; otherwise the appearance was normal. Gradual orientation of the fibrocytes, capillaries and collagen fibres was demonstrated at 1 month and was complete at 3 and 6 months. Comparison between an implanted tunica at 6 months and a control tunica from a normal dog showed no significant histological difference. Conclusion: A homologous acellular matrix graft of the tunica albuginea may be an alternative treatment for severe cases of Peyronies disease.

Assessment of recoverability of kidney function in children with obstructive calcular anuria: multicenter study.

OBJECTIVE Urolithiasis in children can cause considerable morbidity. Our aim was to evaluate the impact of intervention on the recoverability of kidney functions. MATERIALS AND METHODS This prospective study included 93 children (66 boys and 27 girls) with median age of 3 years (range 0-14). Inclusion criteria were presence of anuria, oliguria, serum creatinine >2 mg% and/or hyperkalemia ≥ 6 mmol/L. The mean duration of anuria or oliguria was (mean ± SE) 5.3 ± 0.4 days. On presentation, mean plasma creatinine was 6.5 ± 0.29 mg/dl with a mean estimated glomerular filtration rate (eGFR) of 14 ml/min and creatinine clearance (CC) of 8.24 ml/min. Dialysis was performed in 21 (22.6%) patients. When condition allowed, emergency surgery was performed. RESULTS Mean follow up was 1.5 years with compliance of 82%. At the end of treatment, 83% of patients had complete clearance of calculi. Mean plasma creatinine after treatment was 3.3 ± 0.35 mg/dl with an average GFR of 24.5 ml/min. After treatment renal function returned to normal in 57%, improved in 27% and deteriorated in 16% of children. Renal function recoverability rate was 94.6%. Chronic renal failure developed in 3 (3.2%) patients and 2 (2.2%) patients died. When absolute plasma creatinine concentration [P(cr)] improved 20-50% the eGFR and CC were doubled, and when improved 50-70% eGFR and CC tripled. Beyond 70% improvement in [P(cr)], eGFR and CC improved 7-8 times. Using Spearmans correlation, the mode of presentation and the type of management had a significant correlation with renal function outcome (P = 0.019 and 0.013 respectively). CONCLUSION Urgent management of calcular anuria both medically and surgically is the cornerstone for favorable outcome. The mode of presentation and the type of management are significant factors affecting final renal function outcome.