CHAPTER 22 Cloaca
Step 1: Surgical Anatomy
♦ Cloacal anomalies occur in about 1 in 20,000 live births. They occur exclusively in girls and are the most common defect in female patients, after perineal fistulas and vestibular fistulas. Persistent cloaca was, in the past, considered an unusual defect with a high incidence of rectovaginal fistulas reported in the literature. In retrospect, it seems that cloaca is a much more common defect than reported, as imperforate anus with rectovaginal fistula is an almost nonexistent defect, occurring in less than 1% of all cases. Therefore, most patients with persistent cloaca were probably erroneously thought to have a rectovaginal fistula. Many of those patients underwent operations to correct the rectal component of the malformation leaving them with a persistent urogenital sinus.
♦ The major goals of treatment for cloaca include the achievement of bowel control, urinary control, and sexual function.
Classification
♦ In cloacal malformations, the length of the common channel (Fig. 22-1) varies from 1 to 10 cm, which has important technical and prognostic implications. When the common channel is shorter than 3 cm, patients usually have a well-developed sacrum and good sphincters. In contrast, a cloaca with longer than 3-cm common channel typically is a more complex defect, often with a poor sphincter mechanism and sacrum.
Step 2: Preoperative Considerations
♦ The diagnosis of persistent cloaca is a clinical one. Careful separation of the labia discloses a single perineal orifice, which is pathognomonic for a cloaca (Fig. 22-2). These patients often have small external genitalia. Sometimes patients with cloaca have a palpable lower abdominal mass that represents a distended vagina (hydrocolpos). Failure to recognize the presence of a cloaca in a neonate may be dangerous because more than 90% of these patients have significant associated urologic problems.
Management of Cloacal Malformations During the Neonatal Period
♦ Once the clinical diagnosis of a cloaca has been established, the next step is to perform a rapid urologic evaluation. Abdominal ultrasonography is the most important screening test to rule out the presence of hydronephrosis, hydroureter, or hydrocolpos.
♦ In more than 30% of these cases, the vagina is abnormally distended with mucous secretions and urine (hydrocolpos). The distended vagina may compress the trigone to interfere with the drainage of the ureters and can potentially produce megaureters. The most common error at this stage is to perform only a colostomy in a patient with severe obstructive uropathy, which can lead to acidosis and urinary sepsis. The dilated vagina can also become infected (pyocolpos), and this can lead to vaginal perforation and peritonitis. Such an enlarged vagina may ultimately represent a technical advantage at the time of the definitive repair because of the more abundantly available vaginal tissue for reconstruction.
♦ If a hydrocolpos is correctly identified and drained, obstruction of the urinary tract is usually relieved, thus making urinary diversions such as a vesicostomy, ureterostomy, or nephrostomy unnecessary. Rarely a near-atresia of the urethra exists and a vesicostomy may be required. Drainage of the hydrocolpos can be done by suturing it to the abdominal wall as a small stoma or by placing a transabdominal curled tube.
♦ Attempts to drain the urinary tract or hydrocolpos through the single perineal orifice (common channel) by way of intermittent catheterization or dilatations are not recommended because it is unpredictable whether the catheter will enter the bladder or the vagina. This can be the case particularly with long common channels. Blind dilatations of the single external orifice may also provoke local damage that can interfere with the future repair.
Associated Defects
Müllerian Anomalies
Cloacagram
♦ After the patient has recovered from the colostomy, high-pressure distal colostography as well as injection of contrast through the single perineal orifice and vaginotomy tube or vesicostomy, if present, will help define the cloacal anatomy as well as delineate the location of the rectum, vaginas, or hemivaginas, and vesicoureteral reflux. It is a vital study to help plan the definitive repair. This study can be done in three-dimension, which gives a clear view of the interrelationships of structures.
Step 3: Operative Steps
Endoscopy
♦ An endoscopy is recommended in infants with cloaca to determine the anatomy. The specific purpose of this procedure is to determine the length of the common channel. A separate anesthetic to do this endoscopy within 1 to 3 months of life is the ideal time for this investigation. We avoid endoscopy in the newborn period because it requires a tiny scope, does not afford great visualization, and is difficult because the perineum is often swollen.
♦ Two well-characterized groups of patients with cloaca exist (Table 22-1). These two groups represent different technical challenges and must be preoperatively recognized. The first group includes patients who are born with a common channel shorter than 3 cm. Fortunately they represent the majority of cloacas and usually can be repaired with a posterior sagittal approach only, without a laparotomy. The second group includes patients with longer common channels. These patients usually need a laparotomy, followed by a decision-making process involving vaginal replacement techniques and urologic reconstruction planning that requires considerable experience and special training in urology. It is ideal if these patients are referred to centers dedicated to the repair of these defects.
| GROUP A | GROUP B | |
|---|---|---|
| Common channel | <3 cm | >3 cm |
| Type of operation | Posterior sagittal approach alone | Posterior sagittal and laparotomy |
| Length of procedure | 3 hours | 6-12 hours |
| Hospitalization | 48 hours | Several days |
| Associated urologic defects | 59% | 91% |
| Incidence in our series | 62% | 38% |
| Voluntary bowel movements | 68% | 44% |
| Urinary continence | 72% | 28% |
| Average number of operations* | 9 | 18 |
| Intraoperative decision-making | Relatively easy, reproducible operation | Complex, delicate, technically demanding** |
* Including orthopedic, urologic, cardiac, and general
** Bladder vagina separation, ureteral catheterization, ureteral re-implantation, vesicostomy, cystostomy, bladder neck reconstruction or closure, vaginal switch, vaginal replacement, (using rectum, colon, small bowel)
Colostomy
♦ It is imperative to perform the colostomy proximal enough so that it does not interfere with the future definitive repair. Specifically, the surgeon must leave enough redundant, distal rectosigmoid to allow a pull-through and for potential use of colon for vaginal replacement. (See the colostomy section in Chapter 21).
Drainage of the Hydrocolpos
♦ During the colostomy procedure, it is critical to drain the hydrocolpos when present; this is best accomplished with a pigtailed, curled, rubber tube. Because a significant number of these patients have two hemivaginas, the surgeon must be certain that the tube inserted into the hydrocolpos is actually draining both hemivaginal spaces. Occasionally a window in the vaginal septum is needed to drain both with a single tube. Sometimes the hydrocolpos is so large that it may even produce respiratory distress; such giant vaginas may be drained directly, connecting the vaginal wall to the abdominal wall as a tubeless vaginotomy.
Definitive Repair
♦ The goal of the operation is to separate the rectum from the vagina and place it within the sphincteric mechanism. The urethra and vagina need to be mobilized so that each is a separate orifice at the perineum.
Cloacas with Common Channel Shorter Than 3 cm
♦ With the patient in the prone position, a long midsagittal incision, which extends from the middle portion of the sacrum through the sphincter mechanism and down into the single perineal opening, is performed. All the muscle structures are divided in the midline.
♦ Low cloaca malformations (smaller than 3 cm) are usually associated with a well-developed sacrum, a normal-appearing perineum, and adequate muscles and nerves. Therefore, a good functional prognosis is expected.
♦ The incision is continued down to the single perineal orifice, exposing the entire malformation. All the sphincter mechanism is divided in the midline (Fig. 22-3).
♦ At this stage, the surgeon has an objective idea of the complexity of the defect and can measure directly the length of the common channel. If the common channel is shorter than 3 cm, it is generally feasible to mobilize the entire urogenital sinus (vagina and urethra together), as well as the rectum, without opening the abdomen. This is anticipated in advance by the preoperative endoscopy.
♦ The rectum is opened in the midline, and silk stitches are placed along the edges of the posterior rectal wall. The incision is extended distally through the posterior wall of the common channel. The entire common channel is exposed.
♦ The next step consists of separating the rectum from the vagina. Rectum and vagina share a common wall, as in the case of imperforate anus with rectovestibular fistula.
♦ In the past, the vagina was separated from the urinary tract. This part of the procedure was technically challenging, with inconsistent results along with significant morbidity, most notably urethrovaginal fistula. Presently, once the rectum has been completely separated from the vagina, the total urogenital mobilization can be performed. This consists of the mobilization of both the vagina and urethra as a unit without separating one from the other (Fig. 22-4). After the rectum has been separated, multiple silk stitches are placed along the edge of the urogenital complex to apply uniform traction.
♦ Another series of fine stitches is placed across the urogenital sinus approximately 5 mm proximal to the clitoris (Fig. 22-5). The urogenital sinus is transected full thickness between the last row of silk stitches and the clitoris, taking advantage of the fact that there is a natural plane between it and the pubis. Working in a bloodless field, one can rapidly reach the upper edge of the pubis, where an avascular structure—the suspensory ligaments of the urethra and bladder—can be identified. These give support to the vagina and bladder. While applying traction to the multiple stitches, these ligaments are divided, which immediately provides significant mobilization of the urogenital sinus. With this maneuver, one can gain 2 to 3 cm of length.
♦ Additionally, the lateral and dorsal walls of the vagina can be dissected. All of this mobilization is adequate to repair approximately half of all cloacas, and it is a reproducible maneuver.
♦ The urogenital mobilization has the additional advantages of preserving an excellent blood supply to both the urethra and vagina and of placing the urethral opening in a visible location to facilitate intermittent catheterization when necessary. It also provides a smooth urethra that can be catheterized easily (Fig. 22-6). What used to be the common channel is divided in the midline, creating two lateral flaps that are sutured to the skin to form the patient’s new labia. The vaginal edges are mobilized to reach the skin and to create the introitus. The limits of the sphincter are electrically determined. The perineal body is reconstructed, bringing together the anterior limit of the sphincter. The rectum is then placed within the limits of the sphincter.
Cloacas with a Common Channel Longer Than 3 cm
♦ When the endoscopy shows that the patient has a long common channel, the surgeon must be prepared to face significant technical challenges.
♦ The patient has total-body preparation so that the surgeon can switch between the prone and the abdominal approach, as described for rectobladder neck fistula.
♦ The rectum is separated from the vagina and urethra. A very long common channel (more than 5 cm) cannot be repaired by total urogenital mobilization alone, and therefore the channel should be left in place so that it can be used later for intermittent catheterization. In this situation, if the vagina is tiny and high, it is separated from the posterior urethra in the abdomen by placing multiple fine silk stitches in the vaginal wall to create a plane of dissection between the vagina and the urinary tract. This is a very delicate, meticulous, and tedious maneuver. If the vagina is reachable from the perineal approach, a total urogenital mobilization is performed. If the total urogenital mobilization does not gain enough length to have it reach the perineum, the urogenital complex is delivered into the abdomen for further dissection to gain length. If this maneuver fails to gain adequate length, the vagina must be separated from the urinary tract. Traction sutures are placed in the single uterus or in both hemiuteri. Traction sutures are also placed in the dome of the bladder. With the use of traction on both structures, dissection is initiated between the urinary tract and the vagina. This should be done with the bladder opened and each ureter catheterized. Once the vagina(s) has been separated from the bladder and urethra, the surgeon has to make a decision based on the specific anatomic findings. A single, midsized vagina or two hemivaginas with a septum that has been removed, once separated from the urinary tract, and with preserved blood supply from the uterine vessels, may at this point reach the perineum. When the vagina is too short, some form of vaginal replacement or maneuver is required.
♦ To do this work, a midline laparotomy is recommended; the bladder is opened in the midline, and feeding tubes are placed into the ureters to protect them. The malformations involve a large common wall between the vagina and the bladder. As both the ureters run through this common wall, the dissection is performed very close to them, and therefore they require protection.
♦ Once in the abdomen, the patency of the müllerian structures can be confirmed by passing a no. 3 feeding tube through the fimbriae of the fallopian tubes and injecting saline solution. If one of the systems is not patent, we recommend its excision, giving careful attention to protecting the blood supply of the ovary.
Vaginal Replacement
♦ The vagina can be lengthened or totally replaced with bowel when it is very small and is located very high or in cases of absent vagina. The choices are rectum, colon, or small bowel.
Rectum
♦ Replacing the vagina with rectum is feasible only in patients who have a megarectum that is large or long enough to be divided into a portion with its own blood supply, which will form the new vagina, and a portion with a circumference sufficient to reconstruct an adequate-sized rectum. The blood supply of the rectum will be provided transmurally from branches of the inferior mesenteric vessels (Fig. 22-7). The rectum can be divided transversely if it is long enough or longitudinally if it is wide enough, meticulously protecting the blood supply to each half.
Colon
♦ The colon is an ideal substitute to replace the vagina. Sometimes this type of reconstruction is inhibited by the location of the colostomy. When available, the sigmoid or left colon is preferable. The most mobile portion of the colon must be used to have a piece that has a long mesentery (Fig. 22-8). When the patient has internal genitalia or a little cuff of vagina or cervix, the upper part of the bowel used for replacement must be sutured to the upper vagina. When the patient has no internal genitalia (no vagina and no uterus), the vagina is created and left with its upper portion blind and then used for sexual purposes only.
Small Bowel
♦ The most mobile portion of the small bowel is used for vaginal reconstruction. The mesentery of the small bowel is longer in an area located about 15 cm proximal to the ileocecal valve. A segment of this portion of the small intestine is selected, preserving its mesentery. The continuity of the small intestine is re-established with an end-to-end anastomosis. Two more anastomoses are necessary: one between the segment of small intestine and the upper vagina and one between the lower part of the intestine and the perineal skin (new labia) (Fig. 22-9).
Vaginal Switch Maneuver
♦ This maneuver is applicable only in cases with a specific anatomic variant consisting of a long common channel and two hemivaginas with bilateral hydrocolpos (Fig. 22-10). After separation of the vagina from the urinary tract has been completed, the vagina may be too short to fill the gap between vagina and perineum, and it is therefore impossible to move the vagina down. The transverse diameter of both hemivaginas together may be long enough to reach the perineum, provided one of the hemiuteri is sacrificed.
♦ During separation of the vagina from the urinary tract, it must be remembered that the blood supply to both hemiuteri and hemivaginas reaches the hemiuterus laterally. That blood supply must be preserved until a decision is reached concerning the type of vaginal mobilization to be performed.
♦ To perform the vaginal switch, one of the hemiuteri and the ipsilateral fallopian tube are resected, with particular care being given to preserving the blood supply of the ovary. The blood supply of the hemivagina of that side is sacrificed. The blood supply of the contralateral hemivagina is preserved and should be sufficient for both hemivaginas. The vaginal septum is resected, and both hemivaginas are tubularized into a single vagina, taking advantage of their combined long lateral dimension.
Very High Cloaca
♦ In the highest type of cloaca, one may find two little hemivaginas attached to the bladder neck or even to the trigone of the bladder. In these cases, the rectum also opens in the trigone. The separation of these structures is done abdominally. When that separation is completed, patients are often left with no bladder neck or with a damaged bladder neck. At that point, the surgeon must have enough experience to make a decision whether to reconstruct the bladder neck or to close it permanently. In the first situation, most patients will need intermittent catheterization to empty the bladder, and there is no guarantee that the bladder neck reconstruction will work. In the second situation (permanent closure of the bladder neck), a vesicostomy is created, and the patient will require a continent diversion-type procedure at the age of urinary continence (3 to 5 years old). In this particular type of malformation, the patient also needs a vaginal replacement, which should be done with one of the ways previously described.
Step 4: Postoperative Care
Postoperative Management and Colostomy Closure
♦ In general, the postoperative course is uneventful. Pain is not a significant problem except for those who have undergone a laparotomy.
♦ The Foley catheter is usually retained for 2 to 3 weeks. About 20% of the patients with a common channel shorter than 3 cm will require intermittent catheterization to empty the bladder. Patients with common channels longer than 3 cm require intermittent catheterization 70% to 80% of the time. Therefore, the Foley catheter is left in place as long as the patient shows signs of edema in the genitalia and until the urethral meatus is perfectly visible. Once the urethral orifice can be visualized, the Foley catheter can be removed in the clinic and then the infant is observed to see whether she is capable of emptying the bladder. If she cannot pass urine, we teach the caregiver to pass the catheter intermittently. Bladder emptying should be checked by ultrasound within several weeks of catheter removal. In cases of very long common channels, or if catheterizations are difficult, a vesicostomy may be required until the time of urologic reconstruction.
♦ Intravenous antibiotics are administered for 48 hours. Prophylactic antibiotics are administered orally to avoid urinary tract infections during the period of catheterization. Antibiotic ointment is applied locally for 8 to 10 days. Most patients go home after 2 days or after 3 to 4 days for those who required a laparotomy.
Outcome
♦ A patient who has one to three bowel movements per day, remains clean between bowel movements, and shows evidence of feeling or pushing during bowel movements, has a good bowel movement pattern and usually a good prognosis for bowel control. This type of patient is trainable. A patient with multiple bowel movements or one who passes stools constantly without showing any signs of sensation or pushing usually has a poor functional prognosis.
♦ Cloaca represents a spectrum of defect that can be subclassified on the basis of potential for bowel and urinary control, for which the length of the common channel seems to be the most important prognostic factor. The quality of the sacrum and spine is also vital.
♦ Many patients suffer from a deficient emptying mechanism of the bladder. However, they do not have the typical “Christmas tree” type of neurogenic bladder of spina bifida patients, but rather have a flaccid, smooth, large bladder that does not empty completely. Fortunately, most patients with cloaca have a very good bladder neck. The combination of a good bladder neck and a floppy, flaccid bladder makes these patients ideal candidates for intermittent catheterization, which keeps them completely dry. There are two exceptions to this rule: (1) Patients who have a very long common channel, in which the hemivaginas are attached to the bladder neck; and, after these structures have been separated, the patients are left with no bladder neck or a damaged bladder neck; and (2) the group of a small number of patients who are born with separated pubic bones. These patients have no bladder neck congenitally and they eventually require a continent diversion type of operation. These patients could be described as covered exstrophies.
Step 5: Pearls and Pitfalls
♦ Persistent cloaca was, in the past, considered an unusual defect. It seems that in the literature, patients with persistent cloaca were probably erroneously thought to have a rectovaginal fistula. Making this misdiagnosis can lead to an operation in which the rectal component of the malformation is repaired, but the patient is left with a persistent urogenital sinus.
♦ Failure to recognize the presence of a cloaca in a neonate may be dangerous, as more than 90 percent of these patients have significant associated urologic problems.
♦ The most common error in managing a newborn cloaca is to perform only a colostomy and not a vaginostomy when a hydrocolpos is present. This may leave a patient with an obstructive uropathy, which can lead to acidosis and urinary sepsis.
♦ If a hydrocolpos is correctly identified and drained, obstruction of the urinary tract is usually relieved, making urinary diversions such as a vesicostomy, ureterostomy, or nephrostomy unnecessary.
♦ Attempts to drain the hydrocolpos through the single perineal orifice (common channel) by way of intermittent catheterization or dilatations is not recommended, as it is unpredictable whether the catheter will enter the bladder or the vagina. This applies particularly in cases of long common channels.
♦ In patients with cloaca, gynecologic anatomy must be clarified, either at the time of the main repair or at colostomy closure. When undetected, müllerian anomalies may interfere with the drainage of menstrual blood during puberty. These patients can develop hematometra, hematocolpos, or intra-abdominal pseudocysts from retrograde menstruation.
♦ It is important to perform the colostomy proximally enough, leaving redundant sigmoid distally, to avoid having it interfere with the repair of the malformation to allow a pull-through and for potential use of colon for vaginal replacement.
♦ Two well-characterized groups of patients with cloaca exist. The first includes patients who are born with a common channel shorter than 3 cm. These patients can usually be repaired with a posterior sagittal approach only, without a laparotomy. The second group comprises patients with longer common channels. These patients usually need a laparotomy, followed by a decision-making process involving vaginal replacement techniques and urologic reconstruction planning, which requires considerable experience and special training in urology.
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