OASIS

Question 1

What are the names of the two brothers who fronted the hit 90’s band Oasis?

Answer 1

Noel and Liam Gallagher

Question 2

What is the recurrence risk of an obstetrical anal sphincter injury?

Answer 2

4-8%

Question 3

Describe the extent of injury in each of:
3a tear
3b tear
3c tear

Answer 3

3a: <50% of external anal sphincter involved
3b: >50% of external anal sphincter involved
3c: internal anal sphincter involved

Question 4

What can be given to reduce the risk of complications if 3rd degree tear diagnosed?

Answer 4

1) IV antibiotics -single dose of 2nd generation cephalosporin, cefoteten, or cefoxitim
2) laxatives
3) analgesia -tylenol/NSAID recommended, caution with opiates due to constipation
4) pelvic floor physiotherapy if anal incontinence

Question 5

Name potential long-term complications of an OASIS?

Answer 5

1. anal incontinence
2. pain/dyspareunia
3. abscess
4. altered sexual function
5. wound breakdown
6. recto-vaginal fistulae

Question 6

Which patients should get a DRE prior to repair according to the SOGC guideline?

Answer 6

Any patient with a tear > 1st degree prior to suturing

Question 7

What is the rate of OASIS (3rd or 4th degree tear)?

Answer 7

4-6% of SVDs

Question 8

What are the risk factors for OASIS? (There are many)

Answer 8

Maternal: primiparity, age > 35, race, DM, infibulation, obesity (protective)

Delivery: AVD (forceps > vacuum, but vacuum + forceps OR 8), episiotomy, epidural, 2nd stage > 1h, shoulder dystocia, VBAC, water birth, oxytocin augmentation

Infant: BW>4kg, malpresentation, post maturity, fetal distress, OP

Question 9

What interventions protect against OASIS?

Answer 9

head control
perineal support (evidence mixed)
warm compresses to perineum
intrapartum perineal massage