The purpose of this chapter is to discuss the work up and evaluation of the recipient bladder and to discuss how to optimize the native bladder. Many children needing renal transplantation will have renal failure secondary to lower urinary tract disease such as posterior urethral valves, neurogenic bladder from spina bifida, or other genitourinary anomalies such as Vesicoureteral Reflux, bilateral ectopic ureters, etc. There are several goals the transplant team needs to have to allow the recipient patient to have an adequate bladder reservoir for renal transplantation.
GOALS OF PREPARING THE BLADDER FOR TRANSPLANT
Allow for unobstructed drainage of urine into the bladder reservoir
Provide a low-pressure storage reservoir (pressure <30 cm H2O)
Allow for volitional emptying of the reservoir while staying continent (dry for 3 hours)
Normal voiding (Figure 87-1)
Intermittent catheterization via the native urethra
Intermittent catheterization via a continent catheterizable channel (Mitrofanoff)
Prevention of urinary tract infections (UTIs) and stones
Phases of voiding. Phase 1 is the filling and storage phase characterized by relaxation of the detrusor muscle and contraction of the urethral sphincter. Voiding occurs during the phase 2 whereby the detrusor muscle contracts and the urethral sphincter relaxes allowing urine to pass. Voiding ends in phase 3 when the urethral sphincter is closed and the detrusor muscle ceases to contract.
Voiding. Normal voiding is characterized by coordinated relaxation of the urinary sphincter and contraction of the detrusor muscle. Voiding dysfunction may be due to uncoordinated sphincter relaxation and detrusor contraction resulting in abnormally thick-walled bladder due to contraction against a closed bladder outlet.
PRE-TRANSPLANT ASSESSMENT OF THE BLADDER
Assessment For All Transplant Candidates
Detailed Assessment of the Abnormal Bladder
Cystogram. Left- normal smooth walled bladder with regular contour. Middle- small capacity bladder with slight trabeculations. Right - severe neurogenic bladder, with Christmas tree oblong shape and trabeculations.
Voiding Cystourethrograms in voiding phase demonstrating urinary obstruction from Posterior Urethral Valves (Left) and normal urethral shape (Right).