Transcript THE MANAGEMENT OF THIRD- AND FOURTH
THE MANAGEMENT OF OBSTETRIC ANAL SPHINCTER INJURY
(EVIDENCE BASED)
Dr. Ashraf Fouda
Ob./Gyn. Consultant Damietta General Hospital
Sources of Guidelines
The Cochrane Library.
Medline and PubMed
.
UpToDate ®
August 2006 .
RCOG
March 2007, THE MANAGEMENT OF THIRD- AND FOURTH-DEGREE PERINEAL TEARS .
RCOG
June 2004 , METHODS AND MATERIALS USED IN PERINEAL REPAIR .
American Family Physician
October 2003 .
Muscles of perineal body
Applied anatomy
The
anal canal
measures about 3.5 cm in length.
The
external anal sphincter
(EAS) is striated muscle and is subdivided into subcutaneous, superficial and deep regions and is responsible for voluntary
squeeze and reflex contraction pressure
It is innervated by the
pudendal nerve
Applied anatomy
The
internal anal sphincter
(IAS) is a thickened continuation of the circular smooth muscle of the bowel. It contributes about
70%
of the resting pressure and is under autonomic control .
Introduction
Obstetric anal sphincter injury includes both
third- and fourth-degree perineal tears
.
Introduction
The overall risk of obstetric anal sphincter injury is
1% of all vaginal deliveries
.
This condition may also present in women without obvious anal sphincter tears during labour and delivery
(occult injury).
Importance
Anal incontinence
is defined as any
involuntary loss of faeces, flatus or urge incontinence
that is adversely affecting a woman’s quality of life.
Up to 40%
of women with third or fourth degree perineal tears during childbirth suffer from anal incontinence.
Classification and terminology of perineal tears
by
International Consultation on Incontinence and
the RCOG.
First degree
Injury to perineal skin only .
Second degree
perineal muscles Injury to perineum involving but not involving the anal sphincter.
Third degree
Injury to perineum involving the anal sphincter complex (EAS and IAS) :
3a:
Less than 50% of EAS thickness torn.
3b:
More than 50% of EAS thickness torn.
3c
: Both EAS and IAS torn.
Fourth degree
Injury to perineum involving the anal sphincter complex and anal epithelium .
THIRD DEGREE PERINEAL TEAR FOURTH-DEGREE PERINEAL TEAR
Risk factors for obstetric anal sphincter injury
Birth weight over 4 kg Persistent occipitoposterior position Nulliparity Induction of labour Epidural analgesia Second stage longer than 1 hour Shoulder dystocia Midline episiotomy Forceps delivery
Prediction and prevention of obstetric anal sphincter injury
When
episiotomy
is indicated, the
mediolateral technique
is recommended, with careful attention to the
angle
cut away from the midline.
Grade B
Prediction and prevention of obstetric anal sphincter injury
With introduction of
endoanal ultrasound
, sonographic abnormalities of the anal sphincter anatomy has been identified in
up to 36%
of women after vaginal delivery, in prospective studies.
A lower risk
of third-degree tear is associated with a
larger angle
of episiotomy.
Normal anal ultrasound
How can the identification of obstetric anal sphincter injuries be improved?
All women having a vaginal delivery with evidence of genital tract trauma should be
examined systematically
to assess the severity of damage prior to suturing.
Grade B
Surgical techniques
For repair of the external anal sphincter, either an
overlapping or end-to-end (approximation) method
with equivalent outcome. can be used, Where the
IAS
can be identified, it is advisable to repair separately with interrupted sutures.
Repair of third- and fourth-degree tears should be conducted in an
operating theatre, under regional or general anaesthesia.
(Grade A)
End-to-end (approximation) method Overlap technique
Surgical techniques
A systematic review on the method of repair showed that no significant difference in:
perineal pain ,dyspareunia ,flatus incontinence and faecal incontinence & quality of life
between the two repair techniques at 12 months But showed a
significantly lower incidence in faecal urgency
in the overlap group.
(Grade A)
Surgical techniques
Repair in an
operating theatre
will allow the repair to be performed under aseptic conditions
with appropriate instruments, adequate light
and an assistant.
Regional or general anaesthesia
will allow the anal sphincter to relax , which is essential to retrieve the retracted torn ends of the sphincter without any tension
(Grade C)
Choice of suture materials
The use of absorbable synthetic material polyglactin 910 (vicryl) when compared with catgut , is associated with
less :
Perineal pain,
Analgesic use,
Dehiscence and
Resuturing ,
but
increased suture removal .
(Grade A)
Choice of suture materials
The use of a more rapidly absorbed form of polyglactin 910
(Vicryl®)
is associated with a
significant reduction in pain and a reduction in suture removal
when compared with standard absorbable synthetic material. In the light of current evidence,
rapid-absorption polyglactin 910 (Vicryl®)
is the most appropriate suture material for perineal repair.
(Grade A)
Choice of suture materials
When repair of the
IAS
muscle is being performed, fine suture size such as 3-0 PDS and 2-0 Vicryl may cause less irritation and
Burying of surgical knots
beneath the superficial perineal muscles is recommended to prevent knot migration to the skin.
(Good practice point)
Method of repair
A
loose, continuous non-locking suturing
for (vaginal tissue, perineal muscle and skin) & the use of a
continuous subcuticular technique for perineal skin
closure is associated with
less short term pain
than techniques employing interrupted sutures.
(Grade A)
Surgical
competence
Obstetric anal sphincter repair should be performed by appropriately
trained practitioners.
Formal training
in anal sphincter repair techniques, is recommended as an essential component of obstetric training.
(Good practice point)
Postoperative management
The use of
broad-spectrum antibiotics
is recommended to reduce the incidence of postoperative infections and wound The use of
postoperative laxatives
is recommended to reduce the incidence of postoperative wound dehiscence.
(Grade C)
Postoperative management
All women who have had obstetric anal sphincter repair should be : Offered
physiotherapy and
pelvic-floor exercises for 6–12 weeks after repair.
Reviewed 6–12 weeks postpartum by a consultant obstetrician and gynaecologist.
(good practice point)
Prognosis
Women should be advised that the prognosis following EAS repair is good, with
60–80% asymptomatic
at 12 months . Most women who remain symptomatic describe
incontinence of flatus or faecal urgency
.
(Grade A)
Future deliveries
All women with an obstetric anal sphincter injury in a previous pregnancy should be :
Counselled
about the risk of developing anal incontinence or worsening symptoms with subsequent vaginal delivery.
Advised
that there is no evidence to support the role of prophylactic episiotomy in subsequent pregnancies.
(good practice point)
Future deliveries
All women with an obstetric anal sphincter injury in a previous pregnancy and who are symptomatic or have abnormal endoanal ultrasonography should have the option of elective caesarean birth.
(good practice point)
Risk management
There is a steady increase in
litigation
related to obstetric anal sphincter injury.
Litigation
is related to failure to identify the injury after delivery , leading to subsequent anal incontinence and rectovaginal fistulae.
Poor technique, poor materials or poor healing may cause a repair to fail.
Practice recommendations
Avoiding obstetrical injury to the anal sphincter
is the single biggest factor in preventing anal incontinence . Any form of
instrumental delivery
has been noted to increase the risk of obstetric anal sphincter injury and altered fecal continence , by between 2-7 fold .
Practice recommendations
Routine
episiotomy is not recommended.
Episiotomy
use should be
restricted to
situations where it directly facilitates an urgent delivery .
A
mediolateral incision
, instead of a midline, should be considered for persons at
high risk
of obstetric anal sphincter injury ,with careful attention to the
angle
cut away from the midline.
Practice recommendations
The internal anal sphincter needs to be separately repaired, if torn .
Women with injuries to the internal anal sphincter or rectal mucosa have a worse prognosis for future continence problems .
Practice recommendations