Perineal Trauma

Question 1

What are antenatal risk factors for OASIS injury?

Answer 1

Asian ethnicity, RR 2.3
Nulliparity, RR 7
BW > 4kg, RR 2.3
Short perineal length <=2.5 cm

Question 2

What are intrapartum risk factors for OASIS injury?

Answer 2

Prolonged second stage, RR 1.5-2 (depending on how prolonged)
OP position, RR 2.4
Instrumental delivery

Shoulder dystocia, RR 1.9

Question 3

Use of ____ is recommended for 10/7 following the repair of an OASI injury

Answer 3

Stool softeners

Question 4

If a woman suffers an OASI injury in her first pregnancy, what is the risk of suffering from one in subsequent pregnancies?

Answer 4

5-7%

Question 5

What are the risks of subsequent vaginal delivery after OASI?

Answer 5

17% women develop worsening faecal symptoms after a second vaginal delivery

This seemed to occur if there had been faecal incontinence beyond 3 months but resolution by 6 months after the index delivery

Question 6

How is a 4th degree perineal tear repaired?

Answer 6

Anorectal mucosa: interrupted sutures with the knot tied within the anal canal. 3/0 Vicryl
IAS: interrupted or mattress sutures WITHOUT overlapping. 3/0 PDS Monofilament OR 2/0 Vicryl
EAS: Either overlapping or end-to-end can be used with equivalent outcomes (no difference in outcomes in a Cochrane Review) 3/0 PDS Monofilament OR 2/0 Vicryl

Figure of 8 sutures should be avoided as they can cause tissue ischaemia

RCOG Guideline

Question 7

12 months after EAS repair (OASI), how many women are asymptomatic?

Answer 7

60-80%

Question 8

What is the description of a Grade 1 perineal injury

Answer 8

Perineal skin and/or vaginal mucosa

Question 9

What is the description of a Grade 2 perineal injury

Answer 9

Perineal muscles

Question 10

What is the description of a Grade 3a perineal injury

Answer 10

<50% external anal sphincter thickness

Question 11

What is the description of a Grade 3b perineal injury

Answer 11

> 50% external anal sphincter thickness

Question 12

What is the description of a Grade 3c perineal injury

Answer 12

Internal anal sphincter

Question 13

What is the description of a Grade 4 perineal injury

Answer 13

Anorectal mucosa

Question 14

What is the description of a rectal buttonhole tear?

Answer 14

Affects anorectal mucosa but the internal anal sphincter is intact.

NB: If not recognised correctly, can result in a Rectovaginal fistula

Question 15

When does a mediolateral episiotomy have a protective effect against OASIS injuries?

Answer 15

In the context of instrumental deliveries

Question 16

What are the four steps to perineal protection

Answer 16

1. Left hand slowing down the delivery of the head
2. Right hand protecting the perineum
3. Mother not pushing when the head is crowning
4. Think about episiotomy

I.e. HANDS ON

Question 17

What were the Cochrane findings, of the review looking at warm compresses and the rate of OASI injury?

Answer 17

Warm compresses reduced the rate of OASI injury

Question 18

What is the definition of anal incontinence?

Answer 18

Involuntary loss of flatus / faeces affecting quality of life

RCOG

Question 19

What type of muscle does the IAS consist of?

Is it under voluntary or involuntary control?

Answer 19

Smooth muscle
Circular
Involuntary control (autonomic: myenteric and gut wall complexes)

Question 20

What type of muscle does the EAS consist of?

Is it under voluntary or involuntary control?

Answer 20

Striated
Skeletal muscle
Voluntary control

Question 21

Which nerve innervates the EAS?

Answer 21

Pudendal nerve

Nerve roots S2-4

Question 22

What three muscles make up the levator ani?

Answer 22

Puborectalis
Iliococcygeous
Pubococcygeous

Question 23

What is the “normal” length of the perineal body?

Answer 23

2.5cm (RCOG)

Average (median) 3.9 according to OASIS course

Question 24

What is the definition of anal urgency?

Answer 24

Inability to defer defecation for more than 15 minutes

Question 25

What were the findings of the Cochrane Review looking at continuous vs interrupted suturing techniques for repair of epis / 2nd degree tears?

Answer 25

Continuous suturing techniques associated with less - short term pain - need for analgesia - suture removal

Question 26

What was the finding of the Cochrane Review looking at Antibiotic prophylaxis for 3rd and 4th degree tears

Answer 26

Suggest that prophylactic antibiotics help to prevent perineal wound complications Loss to follow up was high so caution required

Question 27

Which sphincter is responsible for most of the anal tone?

Answer 27

Internal anal sphincter | 70-80%

Question 28

What is the length of the total anal sphincter complex?

Answer 28

2.5cm

Question 29

What is anal continence maintained by?

Answer 29

Rectum: provides compliance and sensation Ano-rectal angle IAS: passive barrier to leakage EAS: physic contractions Anal mucosal folds / cushions: provide pads to completely close anus, 15% resting tone

Question 30

What is the incidence of OASI?

Answer 30

3%

Question 31

What % of repaired OASI have residual EAS defects?

Answer 31

20-35%

Question 32

What muscles are cut with a mediolateral episiotomy?

Answer 32

Transverse perineal muscles | Bulbocavernosus muscles