Obstetric Anal Sphincter Injury An update on best practices Erin Crosby MD Assistant Professor Department of OB/Gyn Division of FPMRS 1 Objectives Describe the anatomy of the anal sphincter complex Discuss the epidemiology of OASIS Review the best practices in repair of OASIS 2 1
3 Anatomy Delancey 1997 4 2
Hsu 2005 5 Hsu 2005 6 3
Classification of OASIS 7 Classification First degree laceration injury to skin and subcutaneous tissues of the perineum and vaginal epithelium only Second degree laceration extends into the fascia and muscle of the perineum Third degree lacerations involve some or all of the EAS and/or IAS Fourth degree laceration disruption of the EAS, IAS and rectal mucosa 8 4
Classification Subclassification for third degree lacerations 3a: <50% of EAS is torn 3b: >50% of EAS torn 3c: IAS torn with complete rupture of EAS When in doubt, classify it to the higher degree 9 ACOG Practice Bulletin 165 Epidemiology Incidence is ~3-6% in nulliparous women Risk factors Operative vaginal delivery Midline episiotomy Increased fetal birth weight Other obstetrical factors 10 5
Risk factors Operative vaginal delivery Incidence of OASI is higher with any operative delivery (vacuum 11%, forceps 20%) Incidence of OASI is higher with forceps assistance compared with vacuum assistance (RR 1.9, 1.5-2.4) Many variables considered when making that decision 11 O Mahoney F Cochrane Review 2011 Landy HJ 2011 Episiotomy Why did many OB providers do routine episiotomies? Preservation of the pelvic floor/prevent OASI Expedited delivery of fetus Prevent soft-tissue dystocia Ease of repair/better wound healing 12 6
Episiotomy Why don t we do routine episiotomies anymore? Extension to OASI Increased blood loss Pain Higher rates of wound issues Sexual dysfunction Possible increased risk of perineal laceration in subsequent deliveries 13 Obstet Gynecol 1990 14 7
Shiono 1990 15 Shiono 1990 16 8
Episiotomy Adjusted OR for OASIS with midline episiotomy in primiparous women = 4.2; 95% CI 1.8-10.0 Adjusted OR for OASIS with mediolateral episiotomy in primiparous women = 0.4; 95% CI, 0.2-0.9 17 Episiotomy 18 9
Episiotomy Mediolateral episiotomy Cut angle is different than the suture angle Kapoor DH 2015 19 Episiotomy Kapoor DH 2015 20 10
Episiotomy The risk of OASI with mediolateral episiotomy is ~0.5% with a 45 suture angle Consider cutting a mediolateral episiotomy at a 60 angle Begin 1-2 cm to the midline, cut more than 1.5 cm 21 Recognition 22 11
Recognition First vaginal delivery Two exams immediately after delivery EUAS before suturing 241 subjects, 72% midwife deliveries, 28% physicians 91% of deliveries by physicians were instrumented 23 12
Recognition Delivering doctors diagnosis (%) Research fellow diagnosis (%) Intact perineum 0 0 First degree tear 1 (1.5) 1 (1.5) Second degree tear 45 (66.2) 38 (55.9) Third-fourth degree tear 22 (32.4) 29 (42.6) When midwife data is also included, the prevalence of OASIS increased significantly from 11 to 25%! 25 Recognition Index finger in the rectum, thumb rolls over the anal sphincter 26 13
Repair Consider delivering placenta before repair Move to the operating room If feces present, consider a gentle chlorhexidine scrub 27 Delayed repair does not worsen the outcome! 14
Repair Analgesia Consider redosing the epidural to relax the EAS Bilateral pudendal nerve block Saddle block General anesthesia 29 Repair - Antibiotics Fig. 1. Perineal wound complication rates (%) for patients receiving antibiotics or placebo. The total wound complication rate is less than the two components because some women had both suboutcomes. Wound disruption P=.162; purulent discharge P=.036; any complication P=.037.Duggal. Prophylactic Antibiotics for Perineal Repairs. Obstet Gynecol 2008. Duggal 2008 30 15
Repair Identify the structures Pack vagina for uterine bleeding Gelpie retractor Adequate assistance 31 16
Repair Choice of suture Standard absorbable suture and not catgut Less pain (OR 0.83, 95% CI 0.7-0.98) Less need for analgesia postpartum (OR 0.71, 95% CI 0.6-0.8) Lower risk dehiscence (OR 0.25, 95% CI 0.08-0.7) Higher risk of needing suture removal Monofilament vs braided Kettle C 2010 Repair Surgical technique Restore continuity of anal sphincters Create a thick perineal body and rectovaginal septum Lengthen the anal canal Hemostasis The finer the suture, the finer the surgeon 34 17
UTD 35 Repair Anal mucosa Continuous, nonlocking 3/0 polyglactin (Vicryl) IAS Retracts laterally and superiorly Thickened, pale, shiny tissue Continuous, nonlocking 3-0 PDS or 2-0 polyglactin on a tapered needle 36 18
Repair EAS Grasp with Allis clamps, ends typically retract End to end or overlapping plication 3-0 polydiaxanone (PDS) or 2-0 polyglactin (Vicryl) At least 4 sutures 37 Repair Fenner DE 19
Repair End-to-end vs overlapping Fernando RJ 2013 Meta-analysis of RCTs showed no difference in continence with two techniques but significant limitations in trials Several RCTs since Overlap may have higher rate of flatal incontinence and postpartum pain Similar fecal incontinence rates Similar residual anal sphincter damage on EAUS 39 Repair Build the distal rectovaginal septum and perineal body (interrupted 2/0 polyglactin) Standard first and second degree laceration repair 40 20
Postpartum care Consider low residue diet Consider polyethylene glycol, milk of magnesia Avoid fiber Try to only use NSAIDS for analgesia Postpartum care Early vs delayed repair Traditionally, secondary repair was deferred for 2-3 months Secondary repair within 2 weeks has success rates of 87-100% Debride the wound in the office, remove suture fragments, sitz baths until free of exudate and granulation tissue present 42 21
Outcomes If OASIS at time of delivery At 6 months 9% fecal incontinence 24% anal incontinence 21% fecal urgency Recurrence with subsequent vaginal delivery If prior OASI, ~5% Subsequent vaginal delivery increases short-term risk of fecal incontinence 43 Richter HE 2015 Boggs EW 2014 Outcomes Obstetric management of subsequent delivery Limited data Consider planned cesarean, especially if persistent anal symptoms 44 22
Persistent OASI Delayed sphincteroplasty - long-term success rate ~10-25% at 10 years Sacral neuromodulation 40% continence rate, 10-40% reoperation rate Decreased efficacy if significant anal sphincter disruption References Mayo Foundation for Medical Education and Research accessed at http://www.mayoclinic.org/diseases-conditions/analcancer/multimedia/the-anal-canal/img-20006922 Pfenninger JL Am Fam Physician. 2001 Jun 15;63(12):2391-2398 Delancey JO et al Obstet Gynecol 1997 Dec 90 (6) 924-927 Hsu Y et al Int J Gynaecol Obstet 2006 RCOG. Green-top guideline no 29; March 2007 Landy HJ Obstet Gynecol 2011; 117:627 Kapoor DH Int Urogynecol J 2015 Andrews V BJOG 2006 Duggal N Obstet Gynecol 2008; 111:1268 Kettle C Cochrane Database Sys Rev 2010; CD000006 Fernando RJ Cochrane Database Sys Rev 2013;12: CD002866 Richter HE Female Pelvic Med Reconstr Surg 2015; 21:182 Boggs EW Ostet Gynecol 2014; 124:128 O Mahony F et al Cochrane Pregnancy and Childbirth Group 2010 Shiono P Obstet Gynecol 1990 Nordenstam J BJOG 2008 23