CHAPTER 6 Congenital Disorders of the Lower Urinary Tract
Describe the formation of trigone during development.
The common excretory ducts (the portion of the nephric ducts distal to the origin of ureteric buds) dilate and become absorbed into the urogenital sinus. The right and left common excretory ducts fuse in the midline as a triangular area, forming the primitive trigone.
How does the bladder appear in prune belly syndrome?
The bladder usually appears massively enlarged with a pseudodiverticulum at the urachus. The urachus is patent at birth in 25% to 30% of children. Histologically, the bladder has an increased ratio of collagen to muscle fibers in the absence of obstruction.
Why are indirect inguinal hernias frequent in exstrophy patients?
This phenomenon is attributed to a persistent processus vaginalis, large internal and external inguinal rings, and the lack of obliquity of the inguinal canal.
What is the rate of occurrence of inguinal hernias in bladder exstrophy?
In a review of 181 children with bladder exstrophy, Connolly and coauthors (1995) reported inguinal hernias in 81.8% of boys and 10.5% of girls.
What is the primary anorectal defect in exstrophy?
The perineum is short and broad and the anus is situated directly behind the urogenital diaphragm; it is displaced anteriorly and corresponds to the posterior limit of the triangular fascial defect.
What is the average corporal length defect in exstrophy patients?
It was found that the anterior corporal length of male patients with bladder exstrophy was almost 50% shorter than that of normal controls.
How does the exstrophy patient’s prostate compare with the normal age-matched control’s prostate?
The volume, weight, and maximum cross-sectional area of the prostate appear normal compared with published control values. However, in exstrophy patients, the prostate does not extend circumferentially around the urethra, and the urethra is anterior to the prostate in all patients.
What is the classic picture of a female exstrophy patient?
The vagina is shorter than normal, hardly greater than 6 cm in depth, but of normal caliber. The vaginal orifice is frequently stenotic and displaced anteriorly; the clitoris is bifid, and the labia, mons pubis, and clitoris are divergent. The uterus enters the vagina superiorly so that the cervix is in the anterior vaginal wall. The fallopian tubes and ovaries are normal.
What is the incidence of reflux after surgical closure of the bladder in exstrophy patients?
Reflux in the closed exstrophic bladder occurs in 100% of cases, and subsequent surgery is usually required at the time of bladder neck reconstruction. If excessive outlet resistance is gained at the time of either initial closure or combined epispadias and bladder exstrophy closure, and if recurrent infections are a problem even with suppressive antibiotics, ureteral reimplantation is required before bladder neck reconstruction.
What are the most significant changes in the management of bladder exstrophy over the past 2 decades?
Currently, bladder exstrophy is managed with (1) early bladder, posterior urethral, and abdominal wall closure, usually with osteotomy; (2) early epispadias repair; and (3) reconstruction of a continent bladder neck and reimplantation of the ureters when necessary. Most importantly, however, a definition of strict criteria for the selection of patients suitable for this approach has been created.
What are the advantages incurred by osteotomy at the time of bladder closure?
Pelvic osteotomy performed at the time of initial closure confers several advantages, including easy approximation of the symphysis with diminished tension on the abdominal wall closure and elimination of the need for fascial flaps. In addition, it allows placement of the urethra deep within the pelvic ring, enhancing bladder outlet resistance. Finally, it brings the large pelvic floor muscles near the midline, where they can support the bladder neck and aid in eventual urinary control.
Why is the combined anterior osteotomy preferred to the classic posterior osteotomy?
Besides the ease of approximation, combined osteotomy was developed for 3 reasons:
1. Osteotomy is performed with the patient in the supine position, as is the urological repair, thereby avoiding the need to turn the patient.
2. The anterior approach to this osteotomy allows placement of an external fixator device and intrafragmentary pins under direct vision.
3. The cosmetic appearance of this osteotomy is superior to that resulting from the posterior iliac approach.
When can you remove the external fixation device after primary closure?
When good callus formation is seen on radiography, the fixation device and pins are removed with the patient under light sedation.
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