Complete Primary Repair for Exstrophy



Complete Primary Repair for Exstrophy


RICHARD W. GRADY



Bladder exstrophy is a congenital anomaly that has consistent external physical manifestations; the diagnosis of exstrophy is usually made immediately after birth, although it can be detected antenatally. The anterior portion of the bladder and/or urethra and abdominal wall structures are deficient, and the pubic symphysis is widely diastatic (Fig. 99.1); the bladder and urethra are herniated ventrally. The exstrophic defects are typically found in isolation; other organ systems are only infrequently affected with classic bladder exstrophy and epispadias. However, children with exstrophy typically have an anteriorly located anus. Female genital anatomy is altered, with a more vertically oriented vaginal opening after closure and a wider and shorter vagina than normal. The anterior component of the penis is also foreshortened in males compared to the general population.




INDICATIONS FOR SURGERY

Exstrophy anomalies are nonlethal in the developed world; children with exstrophy can survive untreated into adulthood (4). However, significant morbidity exists with these conditions if they are left untreated, including total urinary incontinence, bladder and kidney infections, skin breakdown, and tumor formation in the bladder plate. The surrounding skin around the exposed exstrophic bladder is often inflamed secondary to urine contact dermatitis, loss of skin integrity from constant wetness, and secondary infection. In contrast, when these patients receive effective surgical and medical treatment, they can lead productive, healthy lives with minimal morbidity from their underlying urologic abnormality.


SURGICAL TECHNIQUE

Primary goals for exstrophy reconstruction include the following:



  • Urinary continence with volitional voiding


  • Preservation of kidney function with low-pressure urinary storage


  • Functional and cosmetically acceptable external genitalia

Secondary goals for reconstruction include the following:



  • Minimization of urinary tract infections


  • Effective abdominal wall and pelvic floor support


  • Minimization of the risk for malignancy associated with the urinary tract


  • Minimization of the risk for urinary calculi

Surgical reconstruction of exstrophy and epispadias represents one of the most significant challenges for physicians who specialize in the urologic care of children. In the late 1980s, Mitchell devised an anatomic approach that integrated epispadias and exstrophy repair. This operation evolved out of a technique developed for the treatment of epispadias—the complete penile disassembly technique and was inspired by the published experience of Dr. Julian Ansell who employed neonatal reconstruction for these children (5). By employing this technique, the surgeon permits the tissue deformation in exstrophy to return more closely to an anatomically normal position. We have used this approach to surgically treat newborns with exstrophy since 1990. The principles of this operation can be employed in some reoperative repairs or delayed repairs for exstrophy.


Preoperative Care

After delivery, to reduce trauma to the bladder plate, the umbilical cord should be ligated with a zero suture rather than a plastic or metal clamp. A hydrated gel or occlusive dressing may be used to protect the exposed bladder from superficial trauma. These types of dressing are easy to use, keep the bladder plate from becoming desiccated, and stay in place to allow handling of the infant with minimal risk of trauma to the bladder. Plastic wrap is an acceptable alternative. Dressings should be replaced daily, and the bladder should be irrigated with normal saline with each diaper change. A humidified air incubator may also minimize bladder trauma.

We routinely use intravenous antibiotic therapy in the preand postoperative period to decrease the risk for infection following reconstruction. This is critical to the success of the immediate postoperative repair. We also perform preoperative ultrasonography to assess the kidneys and to establish a baseline examination for later ultrasonographic studies. Preoperative spinal sonographic examination should be considered if sacral dimpling or other signs of spina bifida occulta are noted on physical examination.



Operative Considerations

The primary exstrophy closure is typically performed in the neonatal period and as early as 1 to 2 days after birth. We routinely use general inhalation anesthesia. However, nitrous oxide should be avoided during primary closure as it may cause bowel distention, which decreases surgical exposure during the operation and increases the risk of wound dehiscence. Some advocate the use of nasogastric tube drainage to decrease abdominal distention in the postoperative period, but we do not routinely use it postoperatively. We do routinely place an epidural catheter to reduce the inhaled anesthetic requirement during the operation. Tunneling the catheter may reduce the risk for infection if it is left in for prolonged periods after surgery.

For patients older than 2 to 3 days or newborns with a wide pubic diastasis, we perform anterior iliac osteotomies at the time of the exstrophy repair to decrease the tension on the wound closure. Osteotomies assist closure and enhance anterior pelvic floor support, which may improve later urinary continence.

Factors that appear to be important in the operative period include use of osteotomies in selected cases and for newborn closures >48 hours after birth to decrease the tension on the repair, ureteral stenting and bladder drainage catheters placed intraoperatively for use in the postoperative period to divert urine, avoidance of abdominal distention, and use of intraoperative antibiotics.


Complete Primary Repair for Exstrophy Surgical Technique: Boys

After standard preparation of the surgical field, we place transversely oriented traction sutures into each of the hemiglans of the penis. We then mark the lines of dissection (Figs. 99.1 and 99.2). Care is taken in marking these lines to exclude dysplastic tissue at the edges of the exstrophic bladder and bladder neck. This is particularly important at the bladder neck, where dysplastic tissue left in continuity may impair later bladder neck function. Following this, we place 3.5Fr to 5Fr catheters into both ureters and suture them in place with 5.0 chromic suture. Bladder polyps are removed prior to beginning the dissection, since these will occupy space after the bladder is reconstructed (see Fig. 99.2). Initial dissection begins superiorly and proceeds inferiorly to separate the bladder from the adjacent skin and fascia, since it is usually easiest to identify tissue planes in this location. We use tungsten fine-tip electrocautery (Colorado tip) during this dissection to reduce blood loss. The umbilical vessels may be ligated if necessary. We also incise the periumbilical skin circumferentially at this time. The umbilicus will be moved superiorly to a more anatomically normal location and will be later used as the location to bring out the suprapubic catheter (Figs. 99.3 and 99.4).






FIGURE 99.2 View of lines of dissection from Figure 99.1. The urethral dissection is carried along the lateral aspect of the urethral plate.


Penile/Urethral Dissection

Traction sutures placed into each hemiglans of the penis aid in dissection at this point in the operation (see Fig. 99.2). The sutures will rotate to a parallel vertical orientation (Fig. 99.5) because the corporal bodies will naturally rotate medially after they are separated from the urethral wedge (urethral plate plus underlying corpora spongiosa). We begin the penile dissection along the ventral aspect of the penis as a circumcising incision (see line of dissection in Fig. 99.1). This step precedes dissection of the urethral wedge from the corporal bodies because it is easier to identify the plane of dissection above the Buck fascia ventrally (Fig. 99.6). The Buck fascia is deficient or absent around the corpus spongiosum; as the dissection progresses medially to separate the urethra from the corpora cavernosa, the plane shifts subtly from above the Buck fascia to just above the tunica albuginea. It is important to recognize this. Failure to adjust the plane of dissection will carry the dissection into the corpus spongiosum; this will result in excessive, difficult-to-control bleeding during the deep ventral dissection of the urethral wedge from the corporal bodies.

Applying methylene blue or brilliant green to the urethra can help identify the plane between urothelium and squamous epithelium. We routinely inject surrounding tissues with 0.25% lidocaine and 1:200,00 U per mL epinephrine to improve hemostasis. This may assist the dissection. Shallow incisions are made laterally along the dorsal aspect of the urethra to begin the dissection (Fig. 99.7). Sharp dissection is required to develop the plane between the urethral wedge and the corporal bodies. Careful dissection will preserve urethral width and length. This is particularly important because the urethra is often too short to reach the glans penis once the bladder has been moved into the pelvis.

Careful lateral dissection of the penile shaft skin and dartos fascia from the corporal bodies will avoid damaging the laterally located neurovascular bundles on the corpora of the epispadic penis. The lateral dissection on the penis should be superficial to the Buck fascia because of the lateral location of the neurovascular bundles in the epispadic penis.


Complete Penile Disassembly and Deep Dissection

Once a plane is established between the penis and the urethral wedge (Fig. 99.8), the penis may be disassembled into three components: (a) the right and (b) left corporal bodies with their respective hemiglans and (c) the urethral wedge (urothelium with underlying corpora spongiosa). This is done primarily to provide exposure to the intersymphyseal band and to allow adequate proximal dissection. We have found that the easiest plane of dissection to completely isolate the

corporal bodies is proximal and ventral (Fig. 99.9). The plane of dissection should be carried out at the level of the tunica albuginea on the corpora. After a plane is established between the urethral wedge and the corporal bodies, this dissection is carried distally to separate the three components from each other (Fig. 99.10). Complete separation of the corporal bodies increases exposure to the pelvic diaphragm for deep dissection but is not always necessary as extensive dissection of the corporal bodies while leaving the glans attached often provides acceptable exposure to the pelvic diaphragm. The corporal bodies may be completely separated from each other because they exist on a separate blood supply (see Figs. 99.9 and 99.10). It is important to keep the underlying corpora spongiosa with the urethra; the blood supply to the urethra is based on this corporal tissue, which should appear wedge-shaped after its dissection from the adjacent corpora cavernosa. The urethral/corpora spongiosa component will later be tubularized and placed ventral to the corporal bodies. Paraexstrophy skin flaps are not recommended with this technique because this maneuver will place the blood supply to the distal urethra at risk. Because the bladder and urethra are moved posteriorly in the pelvis as a unit (with a common proximal blood supply), division of the urethral wedge is counterintuitive to the intent of the repair. In many cases, a male patient will be left with a hypospadias that will require later surgical reconstruction.

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Apr 24, 2020 | Posted by in UROLOGY | Comments Off on Complete Primary Repair for Exstrophy
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