Surgical Challenge in Pediatric Kidney Transplant: Lower Urinary Tract Abnormality

Lower urinary tract abnormalities are difficult to resolve in pediatric kidney transplant patients. Measure of residual urine, voiding cystourethrography, retrograde urethrography, cystometry, electromyography of urethral external sphincter muscle, urethrometry, and uroflowmetry are the primary methods for evaluation of lower urinary tract abnormalities. Endoscopic resection or ablation of urethral valves is required in children with posterior urethral valve to treat obstruction, but bladder function does not always recover and may deteriorate to end-stage renal failure even after the obstruction is released. This bladder dysfunction in posterior urethral valve defines valve bladder syndrome. Vesicoureteral reflux caused by high vesical pressure can cause even worse renal graft function posttransplant. In our patient group, urinary diversion occurred with Mitrofanoff conduit using an appendix in 6 children, a Yang-Monti channel conduit using ileum in 1 patient, with cystostomy in 3 children, and with augmented cystoplasty in 9 children before or simultaneously with kidney transplant. These procedures should be selected based on the type of lower urinary tract abnormality including bladder function. Recently, we have preferred a continent diversion for self-catheterization in children with lower urinary tract abnormalities. We have conducted 9 augmented cystoplasty procedures using a portion of the sigmoid colon or ileum. Seventeen children retained their own bladders when the transplant ureter was implanted. Most patients needed clean intermittent catheterization, depending on the residual urine volume and a bladder function. Ten-year graft survival rate in kidney transplant in our department is 98% in 36 children with lower urinary tract abnormalities. Lower urinary tract abnormality is not always a risk factor for pediatric kidney transplant; however, a preoperative evaluation is important to choose the best option for urinary diversion.