Anorectal malformations.pptx

ano rectal malformations

1. Anorectal malformations Pushpa Lal Bhadel

2. Introduction Birth defects in which the anus and rectum don’t develop properly.  More frequent congenital anomalies encountered in pediatric surgery. Incidence : 1 in 4000 live births Male > female

3. Introduction In female: Rectovestibular fistula is the most common In male : Rectourethral fistula is the most common Imperforate anus without fistula: 5% Estimated risk of 2 nd child being affected is 1.4% Risk increases to 3% if first child is born with perineal or vestibular fistula

4. Introduction Most female have low or intermediate anorectal malformations while the reverse is true for males. Female babies usually have a fistula from the terminal end of the bowel opening externally While in male this fistula is usually well hidden.

5. Embryology The hindgut gives rise to: distal third of transverse colon, the descending colon, the sigmoid, the rectum and upper part of anal canal

6. Embryology Hindgut enters the posterior portion of cloaca, the future anorectal canal; the allantois enters the anterior portion, the future urogenital sinus. The urorectal septum is formed by merging of the mesoderm covering the allantois and the yolk sac.

7. Embryology As caudal folding of the embryo continues, the urorectal septum moves closer to the cloacal membrane.

8. Embryology Breakdown of the cloacal membrane creates an opening for the hindgut and one for the urogenital sinus. The tip of the urorectal septum forms the perineal body.

9. Embryology Anorectal malformations may be caused by abnormalities in formation of cloaca and/or urorectal septum. For example, if the cloaca is too small or urorectal septum does not extend far enough caudally, the opening of hindgut shifts to anteriorly leading to the opening in urethra or vagina. Imperforate anus occurs when cloacal membrane fails to breakdown.

10. Classification Wingspread classification Pena’s classification Krickenbeck classification Anatomical classification

11. Classification Wingspread classification (1984)

12. Classification Pena’s classification

13. Pena’s classification

14. Classification Krickenbeck classification

15. Classification Anatomical classification

16. Rectoperineal fistula Traditionally was known as a “low defect.” The rectum is located within most of the sphincter mechanism. Only the lowest part of the rectum is anteriorly mislocated .

17. Rectoperineal fistula Sometimes, the fistula does not open into the perineum but rather follows a subepithelial midline tract, opening somewhere along the midline perineal raphe, scrotum, or even at the base of the penis. Diagnosis established by perineal inspection No further investigations required.

18. Rectoperineal fistula The terms covered anus, anal membrane, anteriorly mislocated anus, and bucket-handle malformations all refer to perineal fistulas.

19. Rectourethral fistula Imperforate anus with a rectourethral fistula is most common defect in boys. The fistula may be located at The lower (bulbar) part of the urethra Lower urethral fistulas are usually associated with good-quality muscles, a well-developed sacrum, a prominent midline groove, and a prominent anal dimple. The higher (prostatic) part of the urethra Higher urethral fistulas are more frequently associated with poor-quality muscles, an abnormally developed sacrum, a flat perineum.

20. Recto-bladder neck fistula Rectum opens into the bladder neck Levator muscle, muscle complex, and parasagittal fibers are poorly developed Sacrum is often deformed or absent Entire pelvis is underdeveloped Prognosis for bowel function is poor

21. Recto-bladder neck fistula The perineum is often flat, which is evidence of poor muscle development. About 10% o f males with ano r ec t al a t r esia f all into this category.

22. Imperforate anus without fistula Have a well-developed sacrum and good muscles and have a good prognosis in terms of bowel function. The rectum usually terminates approximately 2 cm from the perineal skin. Common in patients with Down syndrome.

23. Rectal atresia Occur in 1 % of case Born with normal appearing anal canal Often discovered during an attempt to take rectal temperature ~2 cm from the anal verge, there is an atretic or stenotic area The sacrum is normal, the sphincter mechanism is excellent Prognosis is good.

24. Rectal atresia These two structures may be separated by a thin membrane or by dense fibrous tissue.

25. Rectoperineal fistula From the therapeutic and prognostic viewpoint, this common defect is equivalent to the perineal fistula described in the male patient. The rectum is well positioned within the sphincter mechanism, except for its lower portion, which is anteriorly located The rectum and vagina are well separated.

26. Rectovestibular fistula Rectovestibular fistula is the most common defect in girls and has an excellent functional prognosis. The diagnosis is based on clinical examination. Meticulous examination of neonatal genitalia allows clinician to observe normal urethral meatus and a normal vagina, with a third hole in the vestibule which is the recto vestibular fistula

27. Imperforate anus without fistula This defect in female patients carries the same therapeutic and prognostic implications as described for male patients.

28. Persistent cloaca A cloaca is defined as a defect in which the rectum, vagina, and urinary tract meet and fuse, creating a single common channel. This group of defects represents the extreme in the spectrum of complexity of female malformations.

29. Persistent cloaca The diagnosis of persistent cloaca is a clinical one. This defect should be suspected in a female born with imperforate anus and small-looking genitalia. Careful separation of the labia discloses a single perineal orifice.

30. Persistent cloaca The length of the common channel varies from 1 to 7 cm. This distance has technical and prognostic implications. Short common channel less than 3 cm Long common channel more than 3 cm

31. Clinical features in newborn

32. Examination Pelvic floor Absence or presence of anal opening Position of anus – normal or anteposed Bulge in perineum on crying or straining Anal dimple Anal reflex Perineal groove Bucket handle deformity Meconium or mucus run ning up the median scrotal raphe

33. Examination Genitalia B o y Girl

34. Examination Abdomen Large visible loop occupying more than half of abdomen Hydrocolpos (in girl) – palpable lump in lower abdomen

35. Examination Lumbo-sacral spine Occult or obvious spinal dysraphism Absent sacral vertebrae of variable levels

36. Associated anomalies

37. Associated anomalies

38. Management protocol in boys

39. Management protocol in girls

40. Approach to case of ARM History of neonate Clinical examination Investigation

41. Investigations Invertogram Cross table lateral radiography USG abdomen & pelvis(to rule out genitourinary anomalies) Ult r asonog r ap h y a)transperineal b)infracoccygeal MCU,IVP CT Scan, MRI High-pressure distal colostography

42. Invertogram Above PC line – High type ARM Between PC line and I point – Intermediate type ARM Below I point – Low type ARM

43. Investigations Cross table lateral radiograph of a patient

44. Transverse infracoccygeal sonogram shows the distal rectal pouch (R) , which passes through the puborectalis muscle (arrows), indicating low-type imperforate anus. U = urethra

45. Investigations CT scan Mainly required before surgery. Clearly shows the anatomy of sphincter muscles, Levator ani, muscle complex. Delineates the rectal pouch and fistula. Clearly shows the relationship between intestine Surrounding muscles.

46. Investigations MRI Provides better soft tissue imaging . No radiation hazard. Scan is expanded to include pelvis , kidneys and spinal cord in case of associated anomalies. Post operatively it clearly shows whether the pulled through intestine is within Levator ani sling or not

47. Investigations High pressure distal colostography Before the definitive repair, distal colostography is performed. It is the most valuable and accurate diagnostic study to define the anatomy of the anorectal malformation.

48. Investigations High pressure distal colostography Water-soluble contrast medium is instilled into the distal stoma, which fills the distal intestine and enables demonstration of the location of the blind rectum and the precise site of a rectourinary fistula. The contrast medium must be injected with considerable hydrostatic pressure under fluoroscopic control.

49. Investigations High pressure distal colostography The use of a Foley catheter is recommended; it is passed through the distal stoma, the balloon is inflated (2–5 mL), and it is pulled back as far as possible to occlude the stoma during the injection of the contrast medium. This maneuver permits to overcome the muscle tone of the striated muscle mechanism, fill the rectum, and demonstrate the urinary fistula when present.

50. Operative procedures Colostomy Posterior sagittal anorectoplasty Pull through procedures Laparoscopic assisted procedures

51. Colostomy Descending colostomy is preferred. The colostomy is constructed through a left lower quadrant oblique or transverse incision. The proximal stoma is exteriorized through the upper and lateral part of the wound and the mucous fistula is placed in the medial or lower part of the wound.

52. Colostomy The colostomy should be made in the mobile portion of the colon, immediately distal to the descending colon taking advantage of its retroperitoneal attachments, and the mucous fistula is made very small to avoid prolapse. During the opening of the colostomy, the distal intestine must be irrigated to remove all the meconium, preventing the formation of a mega-sigmoid.

53. Colostomy Advantages of descending colostomy Mechanical preparation of the distal colon before the definitive repair is easy due small length of remaining segment. Due to shorter distal segment in patient with recto-urethral or recto-vesical fistula urine is not accumulate in distal segment of colon.(which leads to development of metabolic acidosis) Less chance of development of megarectosigmoid . The incidence of prolapse in the proximal limb of descending colostomies is almost zero.

54. Posterior sagittal anorectoplasty (PSARP) All anorectal malformations benefit from the use of the posterior sagittal approach. The length of the incision depends on the specific defect. The patient is placed in the prone position with the pelvis elevated.

55. Posterior sagittal anorectoplasty (PSARP) Position

56. Posterior sagittal anorectoplasty (PSARP) An incision that starts in the lower portion of the sacrum and extends anteriorly to the anal sphincter. Recto vestibular and recto perineal fistula requires smaller incision so, called limited posterior sagittal ano rectoplasty and minimal po st erior sagi t t al ano r ec t opla s ty r especti v el y .

57. Repair in Boys Recto perineal fistula The repair of these defects consists of a small anoplasty with minimal mobilization of the rectum, sufficient for it to be transposed and placed within the limits of the sphincter. It is done during the neonatal period without a colostomy.

58. Repair in Boys These patients have an excellent prognosis. If they have significant associated spinal or sacral problems an alternative approach, a Pott’s transplant anoplasty , whereby the majority of the perineal body is preserved, the mobilized fistula is brought through a separate incision which is confined to the size of the future neoanal canal.

59. Repair in Boys Rectourethral fistula Most important thing in these cases are to put per urethral catheter. To avoid the catheter to be entered in rectum, the catheter must be intentionally directed anteriorly by the use of a lacrimal probe inserted in the distal tip of the catheter to find its correct path.

60. Repair in Boys Rectobladder neck fistula As it is very high defect both approach (through perineum and through abdomen) is needed. A plasty of the distal dilated portion of the rectum is necessary in some cases to reach the perineal skin. It is also called as abdomino perineal pull through operation.

61. Repair in Boys Imperforate anus without fistula About 5 percent of patients have imperforate anus without a fistula. In both boys and girls, the rectum lies about 2 cm from the perineal skin. The rectum must be carefully separated from the urethra because the two structures have a common wall. The rest of the repair must be performed as described for the rectourethral fistula type of defect

62. Repair in Boys Rectal atresia and stenosis These defects are repaired through a posterior sagittal approach. The entire sphincteric mechanism is divided in the midline. The narrowed area of the distal rectum is opened posteriorly.

63. Repair in Boys Rectal atresia and stenosis The posterior rectum is mobilized to reach the anal skin. No anterior dissection is needed. The sphincter mechanism posterior to the rectum is reconstructed. Any presacral mass is dealt simultaneously in the same operation .

64. Repair in Girls Recto perineal fistula The treatment of rectoperineal fistula in girls is the same as that discussed for boys, except of course that the anterior rectal wall is mobilized off the area behind the vagina.

65. Repair in Girls Rectovestibular fistula Incision in this defect is usually shorter as compare to recto urethral fistula in boys. Starting from posteriorly sphincter mechanism is divided till reach rectal fascia which is helpful in indenting the plane of dissection. Then we go laterally and then anteriorly using this plane.

66. Repair in Girls Rectovestibular fistula Because the rectum and vagina have single wall it is divided using needle cautery. The most common error in performing this operation is incomplete separation of the vagina and rectum. This may create a tense anastomosis between the rectum and the skin, which may provoke dehiscence and recurrence of the fistula

67. Repair in Girls Rectovestibular fistula The anterior limit of the external sphincter is identified using electrical stimulation and the anterior edge of the muscle complex are reapproximated as previously described, creating the perineal body.

68. Repair in Girls Rectovaginal fistula Imperforate anus with a true rectovaginal fistula is extremely rare. A true rectovaginal fistula requires a full posterior sagittal incision. The operation is essentially the same as that described for a rectovestibular fistula, except that it is necessary to dissect much more of the rectum to gain enough length to pull it down to the perineum.

69. PSARP in female Involves a midline incision from the fistula to the putative site of the anus. Division of the muscles in the midline, separation of the rectum from the vagina under vision Placement of the rectum within sphincteric complex and reconstruction of the perineal body. Indications: All low and intermediate type of abnormality in females Revision surgery following cutback operations

70. PSARP-procedure 95

71. 96

72. Abdomino perineal pull through operation Lower bowel is mobilized New passage is created through the pelvic floor keeping close to the urethra Fistulous tract is divided and ligated Bowel can be pulled down and its mucosa stitched to the skin of the newly formed anus. Daily dilatation will be required for at least 3 months

73. Abdominoperineal pull through

74. Laparoscopically assisted anorectal pull through (LAARP) for high ARM Advantages: LAARP allows the surgeon to treat a high lesion like a low lesion. No need to divide the muscle complex from below. Immediately after the procedure strong and symmetric contraction of the sphincter around the neo anus can be seen. It also avoids the complication and multiple procedures associated with colostomy. More rapid return of bowel function Improved cosmetic appearance Shorter postoperative recovery Decreased postoperative complications

75. Post operative care In cases of rectourethral fistula in boys, the urethral catheter is left in place for 7 days. If the urethral catheter is accidentally dislodged, the patient can be observed for spontaneous voiding, which usually occurs. Attempts to reintroduce a urethral catheter is avoided.

76. Post operative care Intravenous antibiotics are administered for 24 hours. An antibiotic ointment is applied to the anoplasty for 5 days. The patient is discharged after 2 days in cases of a posterior approach without a laparotomy or laparoscopy, and after 3–5 days in cases of an abdominal approach. The parents are instructed to keep the incision clean, not to wipe, and to apply antibiotic ointment for 1 week. Two weeks after the operations, anal dilatations are started. On the first occasion, a dilator that fits loosely into the anus is used to instruct the parents, who must carry out dilatation twice daily.

77. Post operative care Every week, the size of the dilator is increased until the rectum reaches the desired size, which depends on the patient’s age. Once the desired size is reached, the colostomy can be closed. Frequency of dilatation should be reduced in following schedule : At least once a day for one month; every third day for one month; twice a week for one month; once a week for one month; and every 2 weeks for three months.

78. Post operative care

79. Post operative care Initially patient may have diaper rash due to multiple bowel movement which is converted to 2 or 3 bowel movement per day in 6 months. Patient with 2 to 3 bowel movement in day, with some feeling on having bowel movement have good prognosis and responds to toilet training.

80. Complication Wound infection Anal strictures Constipation Transient femoral nerve pressure Neurogenic bladder Fecal incontinence

81. Thank you