Operative Vaginal Delivery and Pelvic · PDF fileVaginal birth and the pelvic floor Muscle injury Levator ani muscle: 1. pubovisceral complex pubovaginal, puboperineal, puboanal portions

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Anna Padoa, MD

Urogynecology Service

Dept of Ob & Gyn

Assaf Harofe Medical Center

Operative

Vaginal

Delivery and

Pelvic Floor

Trauma

+ Vaginal birth and the pelvic floor

Mechanisms of injury

Damage to muscles Denervation Damage to endopelvic fascia

Handa et al, Obstet Gynecol.1996 Sep;88(3):470-8


Muscle injury

Levator ani muscle:

1. pubovisceral complex

pubovaginal, puboperineal, puboanal portions

2. puborectalis and iliococcygeus muscles

Ashton-Miller JA, Delancey JO. Annu Rev Biomed Eng. 2009;11:163-76


Muscle injury

The load acting normal to the pelvic floor is approximately 37 N

in quiet standing and 19 N in the supine posture

During a maximum cough: peak load of 129 N

Straining at stool: 92 N

expulsive forces on the fetal head: 16 N at rest, 54 N during a

uterine contraction, and 120 N during a volitional push

Vacuum device: additional traction force of up to 113 N

Forceps: additional traction force can reach 200 N



Muscle injury

Second stage of labor

Overstretching: parts of the muscle that are stretched the most are seen to be injured

Pubovisceral (pubococcygeal): stretch ratio of 3.26.

Iliococcygeus, pubococcygeus, puborectalis: stretch ratios of 2.73, 2.50, and 2.28.

These values exceed the maximum stretch ratio of 1.5 tolerated by striated muscle in nonpregnant

animal preparations



Muscle injury

Women with levator defects may be around twice as likely to develop pelvic organ prolapse later in life.

Levator Avulsion in POP patients (MRI): 55% vs 16% in controls

Rates of Levator Ani damage following vaginal delivery (Trans-perineal US): 18.8%-

38.5% after SVD, 45%-71% after OVD

Albrich SB et al. BJOG. 2012 Jan;119(1):51-60

Dietz HP, Lanzarone V. Obstet Gynecol. 2005 Oct;106(4):707-12

Valsky DV et al. Am J Obstet Gynecol. 2009 Jul;201(1):91.e1-7

Chan SS et al.Ultrasound Obstet Gynecol. 2012 Jun;39(6):704-9

DeLancey JO et al. Obstet Gynecol. 2007Feb;109(2 Pt 1):295-302

Dietz HP, Simpson JM. BJOG 2008;115:979–84.


Muscle injury

When a passive muscle is stretched, its force depends on two

factors:

the strain rate

the product of the strain times the strain rate.

An order-of-magnitude increase in the strain rate can

increase the peak force by 25%.

Hence, a physician performing an instrumented delivery is

probably wise to keep the rate of pelvic muscle

stretch as low as possible by delivering the fetal

head as slowly as is reasonable



Nerve injury

PUDENDAL NERVE STRETCH DURING VAGINAL BIRTH:

the inferior rectal branch exhibited the maximum strain: 35%

which varied by 15% from least perineal descent to most perineal

descent

branches innervating the posterior labia and urethral sphincter

reached values of 15% and 13%

nerves innervating the anal sphincter are stretched beyond the 15%

strain threshold known to cause permanent damage in nonpregnant

appendicular nerve

Lien KC et al. Am J Obstet Gynecol. 2005May;192(5):1669-76


Endopelvic fascia

Isolated breaks in the endopelvic fascia: implicated in the

genesis of cystoceles, vaginal support defects and SUI.

After an acute injury new collagen is formed, which is never

as strong as the original connective tissue.

Following levator ani avulsion, loss of support exposes the

endopelvic fascia to gradual stretching and weakening

In a computerized model simulating vaginal delivery, Lepage

et al found the uterosacral ligaments to be submitted to

traction: for a medium-sized fetal head, uterosacral ligaments

undergo a deformation near 30 %

Lepage J et al.Int Urogynecol J. 2015 Apr;26(4):497-504.

+ Operative Vaginal Delivery and the

Pelvic Floor

Possible damage to pelvic floor function caused by operative

vaginal delivery:

1. Anal sphincter Disruption/ OASIS

2. Urinary Incontinence

3. Pelvic Organ Prolapse

+ Operative Vaginal Delivery and

anal incontinence

Author & date N FU results p

Groutz, 1999 300 primips 3 mo AI 3.8% after SVD, 25%

after VE

.004

Meyer, 2000 25 forceps

82 SVD

10 mo AI 4% after SVD, 5%

after forceps

NS

Peschers, 2003 50 VE

50 SVD

6-24 wks SVD-30%, VD-34%

Abn TRUS 10% vs 27.5%

NS

Casey, 2005 10643 primips Mean 219

days

AI- forceps OR=1.3

Liebling, 2004 184 OVD

209 CS 2 st

1 year AI- OVD OR=1.74

Handa, 2011 1011

SVD/OVD/CS

5-10 yrs AI- no diff between

groups

.195

Macleod, 2013 456 VE

904 forceps

6 wks AI- 1% antenatal, 4.9%

postpartum

.02


OASIS/ Anal incontinence

OVD and risk of OASIS

Samuelsson, 2000: 2883 deliveries

OASIS incidence of 3.3%.

VE=10.7% vs SVD=2.9%. OR=4

Wu, 2005: 393 VE.

OASIS- OP 41.7%, OA 22% (p=0.003)

Groutz, 2011: 2007-2009, 31 784 deliveries

60 OASIS. Among risk factors, VE with OR=10



Minaglia, 2007: 16667 vaginal deliveries. OASIS=10.2%



Lewis, 2008: case-control study. 358 OASIS, 716 controls


OASIS- VE vs forceps


Johanson,

1999

113 VE

115 forceps

4-5 yrs AI- 26% VE vs 15% forceps NS

Weerasekera,

2002

204 VE

238 forceps

NR No difference in OASIS

Damron, 2004 1802

deliveries

NR OASIS: VE: OA 26.6%, OP

33.1%. Forceps: OA 53.6%, OP

71.6%

.0001

Johnson, 2004 308 VE

200 forceps

OASIS: 44.4% of forceps and

27.9% VE

.001

Sheiner, 2005 98445

deliveries

NR 79 OASIS: 19 (24.1%)after VE

and 3 (3.8%) after forceps

?

Bahl, 2013 73 VE

145 forceps

NR OASIS: 10.9% after VE vs 10.3%

after forceps

NS



Sequential Instruments (forceps>>VE) and OASIS

De Leeuw, 2001: Dutch national registry 1994-1995. 238,503

SVD and 46,280 OVD. Overall risk: 1.94%.

OR: fundal pressure 1.23, FP+VE 1.64, FP+forceps 3.04, VE

1.79, forceps 2.73, VE+forceps 4.58

Murphy, 2011: 1360 primiparae.

Sequential use of instruments: greater maternal morbidity than

single instrument use (anal sphincter tear 17.4% versus 8.4%,

adjusted OR 2.1, 95% CI 1.2–3.3)

+ Operative Vaginal Delivery, OASIS

and episiotomy


Youssef, 2005 2153 OVD NR VE: no epi OR=1.7, epi OR=2.3

Forceps: no epi OR=4.7, epi

OR=9.1

De Leeuw, 2007 21 254 VE

7478 forceps

NR 3% VE, 4.7% forceps.

Episiotomy: highly protective for

OASIS

( VE: OR=0.11, forceps:

OR=0.12)

Macleod, 2008 1360 deliv NR Epi: 9.9%; no epi: 7.1%, adjusted

OR= 1.1

Raisanen, 2012 16 802 VE NR OASIS 3.4% in primiparas.

Lateral episiotomy : 46%

decreased incidence of OASIS


and episiotomy

Fitzgerald, 2007: 407 OASIS, 390 no OASIS


and episiotomy

Kudish, 2008: 1996-2006. 46239 singleton vertex vaginal

deliveries. significant reduction in anal sphincter trauma

from 5.4% in 1996 to 1.3% in 2006 and a dramatic drop in the

rates of episiotomy and operative vaginal deliveries

+ Operative Vaginal Delivery is a

risk factor for LUTS

Author & date N FU results

Farrell, 2001 595 6 mo UI: forceps CS- RR 3, SVD- RR 1.5

Viktrup, 2001 278 5 yrs VE risk factor with OR=2.9

Arya, 2001 90 VE, 75 f

150 SVD

New-onset SUI decreased with time in VE

and SVD but not forceps

Liebling, 2004 393 OVD vs CS 1 year OVD: greater risk of UI- OR 3.1

Casey, 2005 3887 primis 219 dd UUI X2 after forceps (P = .04)

Baydock, 2009 717 4 mo UUI- forceps RF (P = 0.008)

Handa, 2011 1,011 5-10 yrs >OVD: SUI: OR 4.45, ; OAB: OR 4.89

Murphy, 2011 1360 OVD UR/UI: seq use OR=3.8. forceps=2.2

Handa, 2012 449 5-10 yrs Forceps delivery risk factor for OAB

(p=0.006)

+ Operative Vaginal Delivery is NOT

a risk factor for LUTS


Johanson, 1999 113 pts VE, 115

pts forceps

5 yrs SUI : 7.1% vs 10.4%.

No diff in other LUTS

Persson, 2000 643 SUI pts > 10 yrs , OR of OVD for SUI

surgery 0.78

Meyer, 2000 151 primiparae 10 months No diff in SUI for SVD

vs forceps

Thompson,

2002

1193 pts 24 wks No diff in SUI for SVD

vs OVD

Peschers, 2003 50 pts SVD, 50

pts VE

6-24 wks No difference in

LUTS

Fritel, 2005 2625 pts > 10 yrs OR for forceps 0.8%

MacArthur,

2005

4214 women 6 yrs OR for forceps 0.99

OR for VE 0.93


Pelvic Organ Prolapse


Moalli, 2003 80 POP

176 cont

forceps delivery OR=3.2

Dannecker,

2004

26 SVD,

49 VE,

20 nullip

VE vs nullips: decrease in PB

length (2.5 cm versus 3.2 cm)

Handa, 2011 1011 5-10 yrs at least one OVD- OR=7.5

Handa, 2012 1011 Forceps OR=1.95, VE no incr risk

Glazener, 2013 3763 12 yrs Forceps OR=0.64 for POP

Uma, 2005 352 POP Forceps OR=0.94

Tegerstedt,

2006

454 POP No increased risk with OVD history

Gyhagen 2013 5199 w

663 POP

20 yrs VE not associated with increased

risk of POP

Volloyhaug 2015 608 pts 16-24 yrs Forceps vs VE OR=1.72 for POP > 2

+ When shall CS for POP and SUI

prevention be considered?

SUI after SVD

Recognized risk factors

Advanced maternal age

High BMI

Diabetes

SUI before or during

pregnancy or puerperium

Increasing number of births

Prolonged labor

Operative (especially

forceps) delivery

POP after SVD

Recognized risk factors

Increasing number of births

Operative (especially

forceps) delivery

+

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Operative Vaginal Delivery and Pelvic · PDF fileVaginal birth and the pelvic floor Muscle injury Levator ani muscle: 1. pubovisceral complex pubovaginal, puboperineal, puboanal portions