Clinical and manometric postoperative evaluation of posterior sagital anorectoplasty ( PSARP ) in patients with upper and intermediate anorectal malformations

PSARP is currently the most widely-used surgical technique for surgical correction of high and intermediary anorectal malformations, but there is much controversy in the literature about the postoperative evaluation of these cases. We studied 27 cases of anorectal malformations operated with PSARP from clinical and manometric aspects in order to analyze: 1) fecal continence; 2) the relationship between fecal continence and the associated sacral anomalies and; 3) the relationship between the postoperative manometric evaluation and fecal continence: From the analysis of 27 cases of high and intermediary anorectal malformations, we concluded that: 1) fecal continence was achieved in 48.14 percent of the cases; partial fecal continence in 25.92 percent; and fecal incontinence in 25.92 percent of the cases; 2) the presence of fecal incontinence was directly related to the association of sacral anomalies and; 3) anorectal manometry is a useful test to evaluate the patients operated by PSARp' due to the existence of a relationship between the manometric results and the degree of fecal continence.


INTRODUCTION
A norectal malformations (ARMs) still present a great challenge to the pediatric surgeon.Since the studies of Pena and De Vries, 1 posterior sagital anorectoplasty (PSARP), has become the main treatment for upper and intermediate ARMs in most pediatric centers around the world.These authors also highlighted the importance of sacral malformations by stating that sacral and ARMs together lead to less favorable postoperative results.
Postoperative evaluation of patients with ARMs is very controversial.Therefore, we evaluated clinical and manometric results of 27 children with upper and intermediate ARMs who underwent PSARP.

PATIENTS
We studied 27 white chi Idren with 21 upper and 6 intermediate ARMs, of which 17 were male and 10 were female, and all of whom presented fistulas (17 urethral, 5   vaginal, 5 vestibular).Ages varied from 4 to II years.These patients underwent colostomies with 2 openings prior to PSAPR, anal dilations with Hegar's candles during the postoperative period, and the closing of the colostomies.We assessed these patients clinically and with anorectal electromanometry in order to evaluate fecal continence, relations between fecal continence and any associated sacral malformations, and relations between fecal continence and electromanometry.
Anorectal manometry was performed with rectal and sph incter balloons. 2We con nected the ba Iloons to press ure transducers (Dixtal) in turn connected to aMP-I 00 amplifier, a video monitor, and a 3-channel register, all of which were functionally constructed and modified to assess anorectal preSSlJre.3.4All exams were done without sedation; register sensitivity was calibrated at N = 10 mm/ mv with a speed of Imm/sec., Manometric assay was done by following these steps: I. Initial resting pressure measurement" (in mmHg).2. Study of sphincter-rectal reflexes by filling rectal balloon and observing the pressure response in the sphincter balloon.Reflexes were considered present when a clear pressure decrease in the sphincter balloon was observed, and considered absent when this was not observed.
3. The pressure response of the sphincter balloon during coughing was measured (in mmHg).
4. The pressure response of the sphincter balloon during voluntary sphincter contraction was measured (in mmHg).
5. The time of sustained, voluntary contraction was measured (in seconds).' 6.The pressure response to stimulation of perianal skin with a needle was measured (in mmHg).
7. The pressure response to patient's crying was measured (in mmHg).
8. The anal pressure was registered after the introduction of sphincter balloon into the upper rectum and constant withdrawal at 1 cm every 5 seconds (simple pressure curve).9.The anal pressure curb was registered during withdrawal of sphincter balloon while patient was either coughing, crying, or voluntarily contracting the anus (stimulated pressure curve).5 Based upon these findings, the children were classified into the following three groups: I. Continent -those who defecated once or twice a day, with no soiling, no fecal or anal alterations, and with good upper and lower rectal contraction during examination.
2. Partially continent -those who defecated three to five times a day, with normal feces and frequent soiling, who presented rectal prolapse, and with moderate upper or lower contraction during rectal examination.
3. Incontinent -children who defecated more than five times a day, with liquid feces and a constant and total fecal loss, an anus with a large opening, rectal prolapse, and a visible loss of feces and who presented light or no upper or lower contraction during examination.
Statistical analysis was done with chi-squared tests for 2XN tables to compare the continent, partially continent, and inco~tinent groups according to the abovemen'tioned characteristics.Analyses of variance using Friendman's rank test were used to compare each patient's, initial pressures, voluntary contraction, and perianal stimulation, and the three groups; in case of significant differences, multiple comparison tests were also performed. 6We used Kruskall-Wallis' test to compare patients of all three groups in relation to pressure values, which were completed by multiple comparison tests.

Fecal continence
Thirteen of 27 cases submitted to PSARP presented fecal continence, 7 cases presented partial continence, and 7 incontinence.

Relation between fecal continence and sacral malformations
This relation is depicted in Table I.

Relation between fecal continence and manometric assays
This relation is show in Table 2 All patients in the three groups presented an absence of the sphincter-rectal reflex.
Statistical analysis of the data showed that initial pressure, pressure after coughing, pressure after voluntary contractio'n, pressure after perianal stimulation, and pressure after crying were significantly higher in continent patients.There were no statistically significant differences when studying sustained contractions.
Analysis of the shapes of the normal and stimulated pressure curves showed that the percentage of normal curves in incontinent patients was significantly lower than in the other patients.Pressure levels showed much higher rates of normality in continent patients when compared to   Figures I, 2, and 3 show manometric readings from a continent, a partially continent, and an incontinent patient, respectively.
Schnaufer et £11.7 demonstrated the applicabi lity of anorectal manometry in the postoperative evaluation of anorectal malformations.Several authors X -'4 have already reported anorectal manometry in this kind of evaluation.
Analysis of the initial pressure of our patients in comparison to fecal continence showed similar results to several other reports; there are pressure ranges defined for continent, partially continent, and incontinent patients, with a direct relation between initial pressure and fecal continence as mentioned by Haberkorn et £11. 15and Iway et £11."et al. 1fi reported during the "First International Symposium of Anorectal Manometry" that it is difficult to establish a pattern in anorectal manometry results, as many types of equipment and different methods of evaluation are used around the world.From 1987 to 1995 we used electromanometry with the balloon method on 1,153 patients,17 and si nce 1995 we have been usi ng computerized anorectal manometry.IX  The absence of the sphincter-rectal reflex among our patients was expected, as they presented upper or intermediate anorectal malformations in which there is either a low-functioning or absent sphincter.Even among lower malformations, in which internal sphincter fibers are rudimentary, II) the reflex is present in only 70 percent of the cases. 20ressu res obtai ned wi th cou gh ing, vo lu ntary contraction, crying, perianal stimulation, and the time of sustained contraction allowed us to evaluated striated muscles of the sphincter complex.Pressures upon coughing give us an idea of the reflexive resistance of the upper part of the anorectal sphincter complex to a sudden rise in abdominal pressure.According to Scharli and Kiesewetter,21 the receptors that trigger reflex contractions may be situated in the puborectal muscle.

Mischalany
Pressure during voluntary contraction is of major importance in manometric evaluation, since it reflects the patient's capacity to halt defecation with the action of the striated muscles of the sphincter complex, by the closing the lower rectum using the external sphincter, and by elevating and tightening the upper rectum using the puborectal muscle.
Perianal stimu lation triggers the contraction of striated muscles according to the degree of stimulation, integrity of the muscle, and innervation.Continence is better in patients with a good response to this stimulation.'4 Pressures after crying allow good sphincter evaluation in small children due to wave contractions that are triggered by tightening reflexes.Some comments should be made regarding pressure curves.Ahran et alY started using pressure curves to evaluate the extension and pressure of the anal canal in operated anorectal malformations, publishing their study in 1976. 10Gil-Vernet et al,22 highlighted the importance of pressure profiles done with progressive withdrawal of catheters from the rectum to the anus at a constant speed, obtaining a pressure curve usecl to evaluate the treatment of fecal incontinence in children who underwent surgical correction of anorectal 'malformations.