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Abnormalities In “Low” Anorectal Malformations (ARMs) and Functional Results Resecting the Distal Three Centimetres

Sunday, October 21, 2012: 10:16 AM
Versailles Ballroom (Hilton Riverside)
Laura Lombardi1, Elisabeth Bruder2, Alberto Attilio Scarpa1, Carmine Del Rossi1, Marc Levitt, M.D.3 and Giuseppe Martucciello4, (1)Pediatric Surgery, Maggiore University Hospital of Parma, Parma, Italy, (2)Pediatric Pathology, University of Basel, Basel, Switzerland, (3)Colorectal Center for Children, Cincinnati Children's Hospital, Cincinnati, OH, (4)D.I.P.E. Gaslini, University of Genova, Genova, Italy

Purpose . “Low” anorectal malformations (ARMs) are considered minor anomalies of the distal rectum and anal-canal development. Nonetheless, the prognosis of the patients affected is far from being excellent as some degree of constipation is frequently complained in the long-term follow-up. Constipation in “low” ARM has been reported in 42-70% of cases. Vestibular fistulas seem to have the highest rate of  constipation (not less than 61.4%). The aim of this study was to evaluate all the histological wall abnormalities  of ARM with recto-perineal and recto-vestibular fistulas  in order to identify features that could explain the bowel dysfunctions. Morover, the resection of distal perineal and vestibular fistulas (last 3 centimeters) allowed to evaluate functional results in “low” ARM series with extensive fistula resection.

Methods . One hundred  and four specimens were collected from 52 patients (32 recto-perineal and 20 recto-vestibular fistulas) during the posterior sagittal anorectoplasty (PSARP). The distal 3 centimetres of aberrant anorectal canals (fistulas) were systematically resected and divided longitudinally. One portion was fixed for immuno-histochemical stainings (PGP 9.5, S-100, NSE), H&E, and tricromic stainings. The frozen sections of the second portion were incubated for enzyme-histochemical stainings (AChE, etc.). The follow-up of forty-two of 52 ARM  were postoperative evaluated at   3- 8 years of age,  and the assessment of outcome after PSARP repair was according Krickenbeck 2005  Meeting parameters.

Results . Muscle coat was abnormal in all cases (100%), showing aspect and absence of organization into the circular and longitudinal layers. The connective tissue was found to be irregular and abnormally represented in 100% of cases. Abnormal vascularization was detected in 5 cases (9.6%). All vestibular (100%) and 71.8% of perineal fistulas showed different degrees of Enteric Nervous System (ENS) anomalies.

In the  series of 42 patients followed up after 3 years of age in which 3 cm of aberrant anorectal canal (fistula) was systematically resected, 40 cases (95.2%)  showed postoperative good continence without use of laxatives (according Krikenbeck 2005 criteria).

Conclusion . Every wall component of the distal rectum can be affected by different structural abnormalities in “low” ARMs. Pediatric surgeons should take into consideration the implications of these structural abnormalities during radical treatment. The resection of a significant portion of the distal fistula seems to permit better functional results.