Preconceptional Counseling of Women with Previous Third and Fourth Degree Perineal Tears

20 Preconceptional counseling of women with previous third and fourth degree perineal tears Maria Memtsa and Wai Yoong INTRODUCTION prevalence of third and fourth degree tears appears to be dependent upon the type of More than 85% of women in the United King- episiotomy practised and thus varies consid- dom (UK) sustain some form of perineal erably. In centers where mediolateral episi- trauma during childbirth1. In the majority of otomy is practised, the rate of OASIS is 1.7% instances, only the perineal skin, vaginal epi- (2.9% in primiparas), compared to 12% (19% thelium and superficial muscles are involved, in primiparas) in units that perform midline and such tears are only rarely associated with episiotomy4. serious sequelae. Tears involving the anal This chapter describes the salient points sphincter, however, can have long-term impact that should be covered at the preconceptional on a woman’s quality of life. Sultan2 originally consultation of a woman who has sustained proposed the classification of obstetric anal a third or fourth degree OASIS. What this sphincter injuries (OASIS) shown in Figure chapter does not cover specifically are the risk 1; this classification was later adopted by the factors of anal sphincter injuries, evidence on Royal College of Obstetricians and Gynae- how to prevent such injuries at first vaginal cologists3 and subsequently internationally delivery, methods of repair of severe perineal accepted. A schematic representation of the tears and management of anal incontinence anal sphincter is depicted in Figure 2. The (whether surgical or medical). First degree: laceration of the vaginal epithelium or perineal skin only. Second degree: involvement of the perineal muscles but not the anal sphincter. Third degree: disruption of the anal sphincter muscles which should be further subdivided into: 3a: <50% thickness of external sphincter torn. 3b: >50% thickness of external sphincter torn. 3c: Internal sphincter also torn. Fourth degree: a third degree tear with disruption of the anal epithelium as well. Figure 1 Classification of perineal trauma 267 PRECONCEPTIONAL MEDICINE Approximately 3–5%5 of women experience fecal incontinence postpartum, but often are Longitudinal Circular smooth smooth reluctant to discuss their symptoms. Bugg and 6 muscle Rectum muscle colleagues distributed questionnaires on uri- nary and anal incontinence to 275 primiparous women 10 months after delivery. Although up Interior to 10% of women had developed new symp- anal toms of fecal incontinence, the authors noted sphincter that only a small proportion had raised the External issue with their doctor or midwife. anal sphincter Because of the intimate nature of this topic, Fat Anus Fat information is better obtained by a questionnaire rather than direct questioning. Specific inquiries that should be incorporated in the Figure 2 Schematic representation of the anal questionnaire include7: canal (modified from Sultan, Thakar and Fenner, • How often do you open your bowels per 20094) week? • Is your stool hard or soft? DIRECTED HISTORY FOLLOWING OBSTETRIC ANAL SPHINCTER INJURY • Is your passage of stool painful? • Do you strain excessively to open your OASIS is associated with both short- and long- bowels? term sequelae to young, otherwise healthy • Do you feel you emptied yourself women. Although the issue of anal inconti- completely? nence (defined as the loss of normal control of bowel action leading to the involuntary pas- • Is there any mucus or blood in the stool? sage of flatus and/or feces) predominates in • Are you able to control your stool? the literature, it is by no means the only effect of anal sphincter damage. Pain, infection, dys- • Can you tell the difference between stool pareunia and sexual dysfunction also may be and flatus (wind)? present and play important roles in the wom- • Do you lose flatus when you do not mean an’s emotional and psychological well-being. to? This section describes the effects of OASIS on bowel function and the questions that should • Do you have any leakage of loose stool? be asked in order to elicit the extent of the • How often do you have loose stool per problem. An accurate description of the events week or day? leading to the injury and details of the repair are important and are most easily obtained by • Do you wear pads? perusing the patient’s prior delivery related • Do you feel stool coming and you are notes. Unfortunately, these are not always suf- unable to stop it? (urge incontinence) ficiently complete as to be truly informative. • Do you feel it after it is too late? (true Anal incontinence, the main long-term effect incontinence). of OASIS, can range from a minor leakage of feculant fluid, through occasional passage of Women who have sustained OASIS should be stool during passage of flatus, to complete loss assessed by a senior obstetrician and detailed of bowel control. debriefing of the circumstances surrounding 268 Preconceptional counseling of women with previous third and fourth degree perineal tears the delivery offered and any concerns explored. • Deficits in anal sphincter function A genital examination should be performed, • The presence or absence of rectoanal looking for scarring, residual granulation tis- reflexes sue and tenderness. At this point, specialist investigations organized to assess anal func- • Rectal sensory function tion, as alluded to in the next section, may be • Defecatory function. considered. The apparatus consists of four components: • An intraluminar pressure-sensing catheter INVESTIGATION OF ANAL • Pressure transducers INCONTINENCE • A balloon for inflation within the rectum In order to complement the information • The recording system. gained at history taking and physical examination, a number of investigations may be No universally accepted standards exist for ordered. Some of these may not be available the equipment and/or the technique, unfor- in a generalist setting and referral to a special- tunately. Thus, it is difficult to compare data ist center may be necessary. Prior to this, the between centers, and it remains to each unit pathophysiology of anal incontinence is briefly to develop its own normogram, preferably considered to better understand the choice of sex and age stratified. Anal sphincter func- investigations. tion is assessed by identifying the functional Observational studies of women suffering anal canal length and by recording the maxi- from anal incontinence postpartum identified mum resting canal pressure and voluntary anal two types of insults: mechanical (i.e. relating squeeze pressure. The length of the functional to muscle/anal sphincters) and neuropathic anal canal is shorter in incontinent patients (i.e. relating to the nerve supply of the mus- than in control subjects; low resting anal tone cles). Injury to the pudendal nerve (which is associated with passive anal incontinence, innervates the anal sphincters) as it courses and low anal squeeze pressure correlates with over the pelvic floor, may result in suboptimal symptoms of urge or stress fecal incontinence. continence. The effect of this type of insult is Having said this, two potentially confound- also thought to be cumulative and worsens ing factors operate in manometry: first, large with subsequent pregnancies. The evidence for diameter probes can distort the anal canal and the above observation comes from studies of falsely record high pressures; and, second, women who had cesarean sections performed pressures in different areas vary at different either electively or in early labor (control levels of the anal cavity. Under these circum- group) compared to women who had a cesar- stances, calculated pressures should be aver- ean section as an emergency in late labor8,9. aged out. The following tests help to assess the struc- The rectoanal contractile reflex (which ture and the physiological function of the anal can be assessed by manometry) is recruited sphincter. at instances when the intrarectal pressure increases above the anal pressure. To prevent fecal leakage, the anal pressure should always Anorectal manometry exceed the intrarectal pressure; therefore, when increased intrarectal pressure is present, Anorectal manometry10 includes a series of e.g. coughing, a multisynaptic response results measurements designed to establish: in contraction of the external anal sphincter 269 PRECONCEPTIONAL MEDICINE maintaining the desired high anal pressure. • Longitudinal layer, which is low to moder- In case of damage to the sphincter (whether ately reflective and consists of pubocervical structural or neurological), the reflex is lost fascia, smooth muscle from the longitudi- and continence is compromised. nal layer of rectum and striated muscle of The purpose of assessing normal rectal sen- the perineum sation is to establish the ability of an individual • External sphincter, which is of low to mod- to determine rectal distension and, therefore, erate reflectivity and can be divided into: the need to defecate. Rectal sensation may be – a subcutaneous part, which starts quantified by using balloon distension, and at the termination of the internal the patient may be categorized into the rectal sphincter hypo- or hypersensitivity group. In general, it is believed that patients with rectal hypo- – a superficial part, which forms a com- sensitivity may experience passive (overflow) plete ring around the anal canal incontinence, while hypersensitivity may pres- – a deep part. ent as urge incontinence. Anal manometry also Figure 3 shows the normal

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