IMPERFORATE ANUS

Speaker: Dr Bhagirath.S.N

Moderator: Dr Sarika

Imperforate Anus

• Incidence: 1 in 5000 births male preponderance

• noticed initially as failure to pass meconium

• Persistence of the cloacal membrane results in an imperforate anus

• can be associated with congenital anomalies such as

Vertebral anomalies-hemi-vertebra, hypoplastic vertebraAnal defectsCardiac defects-atrial septal defect, ventricular septal defect, tetralogy of fallotTracheo-Esophageal, esophageal atresiaRenal defectsLimb defects-hypoplastic thumb, polydactyl, syndactyl, radial aplasia.

Imperforate Anus

High lesions

• rectum ends above the levator ani

muscle

• long term fecal incontinence

• communication with urethra in

males and vagina in females

• surgery-colostomy preceding

repairLow lesions

• rectum ends below the levator ani

muscle

•communication with skin in the

perineum, median raphe of scrotum,

or into the vaginal vestibule• perineal anoplasty with closure of fistula, creation of anal opening, repositioning the rectal pouch into the anal opening.

Imperforate Anus-preoperative assessment

•Assess for other anomalies with

Ultrasound of renal system

Chest X-ray

ECG

Echocardiogram

X rays of lumbar and sacral spine

• Presentations

abdominal distension impairment of ventilation, apnea Bowel ischemia

Imperforate Anus-Anesthetic technique

1. Obtain I.V.access

2. Atropine 20 mcg/kg IV if desired.

3. Induction can be IV or inhalational.

4. Endotracheal intubation and IPPV.

5. Maintenance is with volatile anesthetic in oxygen and air.

6. Patients are positioned supine for colostomy. For anoplasty or EUA of

the perineum the lithotomy position (or as near to it as possible in a

neonate) is used with the hips and knees flexed and then taped in this

position. The child is usually positioned at the far end of the operating

table.

7. Options for analgesia include:

1. Anoplasty: a caudal epidural block as a single injection to block

sacral dermatomes— 0.3-0.5 mL/kg 0.25% levobupivacaine or

similar.

Imperforate Anus-Anesthetic technique

2. Colostomy: requires blockade of thoracic dermatomes. A single

caudal epidural injection—1.25 mL/kg 0.125% levobupivacaine or

similar—or insertion of a caudal epidural catheter. The catheter

can be used for a postoperative infusion.

3. The sacrum is occasionally anatomically abnormal in anorectal

anomalies and a caudal technique may not be possible.

4. An intervertebral epidural to block thoracic dermatomes.

5. IV opioid: morphine sulphate 25-50 mcg/kg IV; fentanyl citrate 1-2

mcg/kg IV.

6. All of these techniques can be supplemented by IV paracetamol

15 mg/kg.

8. Occasionally during a colostomy some volume replacement is

required.

Imperforate Anus-Postoperative care

1. Patients are usually extubated.

2. Maintenance fluids are required until feeding is established.

3. Analgesia should be adequate—paracetamol 15 mg/kg oral 6-hourly

(maximum 60 mg/kg/day) and a weak opioid such as codeine

phosphate 0.5 mg/kg oral 4-hourly.

4. After formation of a colostomy the options are an IV infusion of

morphine sulphate or an epidural infusion of LA usually for 24 hours.