Approach to Ano Rectal Malformations - Dr Padmesh - Neonatology

Approach to anorectal malformations (ARM)

1. APPROACH TO ANORECTAL MALFORMATIONS Dr Padmesh V

2. INTRODUCTION: Incidence: 1 in 4,000 to 1 in 5,000. Anorectal malformations (ARMs): common surgically treated anomalies in the newborn period. Imperforate anus can be divided into: Low lesions, where the rectum has descended through the sphincter complex, and High lesions, where it has not descended through sphincter complex. (Sphincter complex: puborectalis , levator ani , external and internal sphincters)

3. EMBRYOLOGY: Interference in development of anorectal and genitourinary organs at various stages upto 7 to 8 weeks of gestation. Continued communication between the urogenital tract and rectal portions of the cloacal plate causes rectourethral fistulas or rectovestibular fistulas. Anomalies in the pelvic floor as well as the external anal sphincter (which are derived from exterior mesoderm). The higher the rectal pouch, more are the chances of mal-development of the pelvic floor.

4. ETIOLOGY: Consanguinity, HLXB9 gene mutations, and Congenital syndromes Presence of an ARM  E valuate for VACTERL anomalies (vertebral anomalies, anal atresia , cardiac defects, tracheoesophageal fistula and/or esophageal atresia , renal and radial anomalies, and limb defects). Most common association: Caudal regression syndrome

5. Associated Malformations GENITOURINARY Vesicoureteric reflux Renal agenesis/dysplasia Ureteral duplication Cryptorchidism Hypospadias Bicornuate uterus Vaginal septums VERTEBRAL Spinal dysraphism Tethered chord Presacral masses Meningocele Lipoma Dermoid Teratoma CARDIOVASCULAR Tetralogy of Fallot Ventricular septal defect Transposition of the great vessels Hypoplastic left-heart syndrome GASTROINTESTINAL Tracheoesophageal fistula Duodenal atresia Malrotation Hirschsprung disease CENTRAL NERVOUS SYSTEM Spina bifida Tethered cord

6. CLASSIFICATION Gross’ Classification: Earliest classification Differentiation based on levator muscle, i.e. supralevator – for those above the levator ani or infralevator anomalies, for those below the levator ani .

7. NORMAL ANATOMY

8. IMPERFORATE ANUS IN MALES: LOW HIGH

9. IMPERFORATE ANUS IN FEMALES: Vestibular fistula Cloaca Fistula between Rectum and Vulval vestibule All three open into a single orifice

10. CLASSIFICATION Wingspread system Based on gender Based on the postulated position of rectum in relation to the pubococcygeal line and ischium . Position of rectum is determined using plain cross-table radiography in prone position, with the bottom up.

11. CLASSIFICATION Wingspread system

12. CLASSIFICATION Krickenbeck system Divided according to clinical presentation. Divided into major clinical groups and rare/regional variants

13. CLASSIFICATION International Classification

14. PRENATAL EVALUATION Prenatal diagnosis of most ARMs is rare. Presence of a cystic abdominal/pelvic mass in combination with gastrointestinal and urologic anomaly should heighten the suspicion for cloacal anomalies. The use of fetal magnetic resonance imaging (MRI) after 20 weeks of gestation.

15. POSTNATAL EVALUATION Thorough physical examination. A clear understanding of the potential locations for perineal fistulas is essential. Boys: Perineal body Median raphe should be carefully inspected Scrotum Penis

16. Meconium expressed from urethral meatus is indicative of a fistulous connection between rectum and the urinary tract.

17. POSTNATAL EVALUATION GIRLS: Determine Number of orifices Location of perineal orifices Presence of 3 orifices does not exclude an ARM. Presence of 2 orifices is indicative of a urogenital sinus . Genitourinary tract & reproductive tract share a common channel, Gastrointestinal tract has separate opening in normal location. Single orifice: Cloacal anomaly. Reproductive, urinary, and GIT share a common orifice. Most complex form of female ARM Requires extensive evaluation and staged corrective surgery

18. Female Urogenital sinus : 2 orifices

19. Cloacal anomaly : 1 orifice

20. Normal position of anus on perineum is approx halfway (0.5 ratio) between coccyx and scrotum or introitus . If fistulous connections are difficult to identify, wait for 24 hours  meconium descends  facilitates visualization. If Cutaneous fistula can be seen, it is a low lesion. Majority of ARMs do not require emergent surgical intervention. Timing of surgery typically after first 24 to 48 hours. During the first 24 hours, gas and meconium descend through the rectum to either the lowest level of the pouch or into the fistula  more accurate assessment of extent of anomaly.

21. RADIOLOGIC EVALUATION Invertogram at 24 hours of life : Determine distance betwn rectum & perineal skin. Originally: infants held in inverted position  column of gas in rectum rises as high as possible with radio-opaque probe at anal dimple. Now: Newborns placed in prone position with hips and knees flexed to chest . Infant stays in this position with bottom up for some time, and radio-opaque marker is placed at anal dimple. Cross-table radiograph (Minimum 3 minutes duration)  D istance between rectal gas column and bead measured. Rectal gas bubble <1-2 cm from perineal skin  Low lesion >1-2 cm from perineal skin  High lesion

22. LOW ARM: HIGH ARM:

23. RADIOLOGIC EVALUATION Fluoroscopy: contrast study To detect a recto-urinary, rectovaginal , or rectoperineal fistula Fistula is termed Low : if below the levator ani plane High : if it is below the pubococcygeal line (PCL)

24. SURGICAL TECHNIQUES: A) Primary Repair Patients with perineal /vestibular fistulas. Options: Cutback Anoplasty Posterior sagittal anorectoplasty (PSARP). Two weeks after repair, the neo-anus is calibrated using a dilator, and serial dilations performed.

25. SURGICAL TECHNIQUES: B) Staged Repair Rectourethral / rectovesicular fistulas, cloacal anomalies, rare variants, or complex life-threatening associated anomalies. These stages are divided into: 1. Performing a colostomy for enteric diversion, 2. Definite reconstruction, 3. Subsequent restoration of enteric continuity via colostomy reversal.

26. SURGICAL TECHNIQUES: Staged Repair Stage 1: Diverting Colostomy. (Double-barrel colostomy) Proximal end : Ostomy . Distal end: Mucous fistula.(Mucous fistula subsequently used to perform distal colostogram before the second stage)

27. SURGICAL TECHNIQUES: Staged Repair Stage 2: Definitive reconstruction: (At about 1 year age) Two main approaches for reconstruction of ARM: PSARP (posterior sagittal anorectoplasty ) LAARP (Laparoscopy-Assisted Anorectoplasty )

28. SURGICAL TECHNIQUES: Staged Repair Stage3: Colostomy Closure. Once the reconstruction has been performed and healed, the colostomy is reversed. Typically 4 to 6 weeks after reconstruction.

29. OUTCOMES: Depends on (1) Extent and nature of the anomaly, (2) surgical expertise, (3) the presence of associated syndromic anomalies, (4) compliance with an effective and aggressive bowel management program.

30. OUTCOMES: 1. Urinary Incontinence Rates of urinary incontinence ranges between 0% for low anomalies to 10% for high anomalies. 2. Fecal Incontinence Low ARMs had good bowel function with no soiling, whereas one-third of those with “high” or “intermediate” anomalies had fecal soiling. 3. Sexual Function and Fertility Variable outcomes

31. Willis J. Potts: “No congenital anomaly requires more thoughtful surgical care than imperforate anus or atresia of the rectum. In practically every case the future of a child so unfortunate as to be born with an imperforate anus is determined by the adequacy and skill of the first operation”

32. THANK YOU!!!