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morbidity of sphincter damageFrom: Robert J. Woolley (wooll005@gold.tc.umn.edu)Sat Apr 26 23:16:52 1997
Anticipating that somebody might want references for my earlier assertion about the prevalence and persistance of symptoms after obstetric anal sphincter damage, here is my summary of the evidence, from the "Risks" section of my review. B. Morbidity of anal sphincter damage It used to be common belief that proper care of third-degree extensions of midline episiotomies would prevent long-term morbidity. Pratt, for example, wrote in 1942, Òa third-degree laceration of the perineum, when properly repaired, heals as readily as if the muscle were not tornÓ [138]. Twenty years later, papers in the two leading American obstetrics journals concluded ÒIn 1960 it would seem that the fear of a perineal laceration as the result of an extension of a midline episiotomy is unrealisticÓ [139] and ÒWhen necessary, complete perineotomy may be done with relative impunity.É Extension of an episiotomy into the rectum is never to be regarded lightly, but in modern obstetrical practice this complication is not as portentous as formerly thoughtÓ [140]. After the passage of another fourteen years, Beynon tried to persuade her British colleagues that Òa fear of rectal involvement is no longer a justifiable reason for opposing the widespread use of median episiotomyÓ [141]. Unfortunately, a cavalier attitude toward this complication remains apparent in some publications within the last decade [142-143]. Such a position is difficult to maintain in the light of more recent findings [144]. In this section I shall briefly survey the results of the last ten years of investigation into the morbidity of anal sphincter injury. In most cases, subjects include both those with spontaneous third-degree tears as well as episiotomy extensions; this assumes that, in terms of morbidity, the two are equivalent, though this surmise lacks scientific confirmation. These results are only relevant to a discussion of the risks of episiotomy if, as contended in section II.A.1. of this review, episiotomy does actually increase the chance of a patientÕs suffering sphincter damage. Mellerup S¿rensen et al identified 25 Danish women who had experienced perineal rupture during delivery, and compared them with controls matched for age, parity, and use of mediolateral episiotomy [145]. At 52 to 123 (mean 78) months after delivery, 42% of the cases described some degree of anal incontinence (25% for flatus, 13% for loose stools, 4% for normal stools), compared to none of the controls. When a sample of each group was tested with anal manometry, the cases demonstrated shorter anal sphincter length and weaker squeeze pressure than the controls. In London, Sultan et al found that 47% of women with third-degree tears remained symptomatic 6 to 21 months after delivery, with anal incontinence (mostly to flatus, a few to liquid stool) and/or fecal urgency, compared with only 13% of controls [146]. Ultrasonography revealed internal and/or external anal sphincter defects in 85% of women with third-degree lacerations, in all of the symptomatic ones, and in 33% of controls. In those with third-degree tears, the injury tended to occur along the entire length of the sphincter and to both internal and external muscles; in controls the defects were shorter and usually involved only one of the sphincter muscles. Anal manometry recorded lower maximal resting pressure, lower maximal squeeze pressure, and shorter canal length in patients with third-degree lacerations than in controls. The authors believe that these defects are likely to predispose even the currently asymptomatic patients to later fecal incontinence. However, in a separate paper, the same team found an association between performance of a mediolateral episiotomy and the development of occult sphincter defects only in univariate analysis; it disappeared as a significant factor in subsequent logistic regression analysis [147]. A series of three papers from southern Sweden similarly reported on long-term symptoms of women after third-degree tears. Haadem et al surveyed patients two to seven years after delivery, and found that 28 of 59 (47%) had persistent symptoms: 15 with Òincontinence for gas,Ó 4 with Òoccasional incontinence for feces,Ó 5 with dyspareunia, and 4 with perineal pain [148]. Compared to a control group without history of sphincter damage or other anorectal disease, these symptomatic women recorded a higher resting rectal pressure, a lower internal anal sphincter strength, a reduced ability to increase anal pressure, and less resistance to withdrawal of a rectal probe. No control patients, matched for age and parity, reported any of the symptoms mentioned above [149]. In their most recent research, Haadem et al began following women with anal sphincter rupture as soon as they were identified [150]. ÒIncontinence of gasÓ was reported at three months postpartum more frequently by the cases than by control patients, but pain and incontinence of urine and feces were not. Two of three manometric measures of anal sphincter function were lower in cases than in controls several days postpartum and again at three months. Although anal sphincter rupture patients showed modest recovery of objective sphincter function at three months, no further improvement occurred by one year postpartum. In their hospital in Heerlen, the Netherlands, Go and Dunselman followed 20 patients with third-degree obstetric tears also involving the rectal mucosa (sometimes called fourth-degree lacerations) [151]. At six months postpartum, six patients still had anal incontinence (three with flatus, one with Òsemisolid feces,Ó two with formed stools). Of the nine patients who consented to later follow-up, at a mean of 29 months postpartum, three continued to experience such symptoms, though by then none soiled with normal stools. Neither anal manometry nor EMG could reliably distinguish symptomatic from asymptomatic patients, though with such small numbers this result is not surprising. All values were in the Òlow to low normal rangeÓ established previously in normal subjects. Crawford et al surveyed Michiganders nine to twelve months after their first deliveries [27]. Those who had experienced third-degree lacerations had persistent incontinence of flatus, but not liquid or solid stool, more often than those without this complication (odds ratio 7.03). In stark contrast to these several studies, Venkatesh et al reported unusually low ratesÑ101/1040 (9.7%)Ñof any anorectal complications 12 to 72 months after third-degree episiotomy extensions [152]. However, they give no information about the completeness of their ascertainment methods, so their cases may represent only those voluntarily seeking treatment for their symptoms. M¿ller Bek and Laurberg surveyed Danish women two to 13 years after delivery with third-degree tear [153]. About half experienced some degree of anal incontinence after this injury, usually transiently. Those who did had a 17% chance of developing permanent incontinence after a subsequent delivery, a risk nine times greater than those not noticing incontinence after the original injury. The authors concluded that although the symptoms attributable to sphincter damage normally resolve quickly (a finding contrary to those of several other studies discussed in this section), subclinical dysfunction lingers and can be exacerbated by subsequent deliveries in a cumulative and irreversible manner. Surgical treatment of this problem is also perhaps less successful that has previously been thought. At St. MarkÕs Hospital in London, 20 patients with persistent anorectal incontinence had onset of symptoms shortly after a delivery involving anal sphincter division [94]. Of these, 60% also displayed EMG evidence of pudendal nerve damage. Snooks et al predicted that this subset of women would require extensive pelvic floor surgery, rather than simple sphincter repair, in order to regain continence. They confirmed this in a later paper; eight of ten patients without pudendal nerve damage had good or excellent results from sphincter repair, as opposed to only one of nine patients with co-existent nerve damage [154]. As noted in a recent review by Hordnes and Bergsj¿, ÒLong term morbidity of severe laceration, especially anal incontinence, has in general been underestimatedÓ [144]. 138. Pratt JP, Hodgkinson CP, Kennedy CR. Midline episiotomy. Am J Obstet Gynecol 1942; 43:292-296. 139. Barter RH, Parks J, Tyndal C. Median episiotomies and complete perineal lacerations. Am J Obstet Gynecol 1960; 80:654-662. 140. Fleming AR. Complete perineotomy. Obstet Gynecol 1960; 16:172-174. 141. Beynon CL. Midline episiotomy as a routine procedure. J Obstet Gynaecol Br Comm 1974; 81:126-130. 142. Berlin M. Midline episiotomies: More harm than good? Obstet Gynecol 1990; 76:474. 143. Varner MW. Episiotomy: techniques and indications. Clin Obstet Gynecol 1986; 29:309-317. 144. Hordnes K, Bergsj¿ P. Severe lacerations after childbirth. Acta Obstet Gynecol Scand 1993; 72:413-422. 145. Mellerup S¿rensen S, Bondesen H, Istre O, Vilmann P. Perineal rupture following vaginal delivery. Long-term consequences. Acta Obstet Gynecol Scand 1988; 67:315-318. 146. Sultan AH, Kamm MA, Hudson CN, Bartram CI. Third degree obstetric anal sphincter tears: risk factors and outcome of primary repair. BMJ 1994; 308:887-891. 147. Sultan AH, Kamm MA, Hudson CN, Thomas JM, Bartram CI. Anal-sphincter disruption during vaginal delivery. N Engl J Med 1993; 329:1905-1911. 148. Haadem K, Dahlstrom JA, Ling L, Ohrlander S. Anal sphincter function after delivery rupture. Obstet Gynecol 1987; 70:53-56. 149. Haadem K, Ohrlander S, Lingman G. Long-term ailments due to anal sphincter rupture caused by deliveryÑa hidden problem. Eur J Obstet Gynecol Reprod Biol 1988; 27:27-32. 150. Haadem K, Dahlstršm, Lingman G. Anal sphincter function after delivery: a prospective study in women with sphincter rupture and controls. Eur J Obstet Gynecol Reprod Biol 1990; 35:7-13. 151. Go PM, Dunselman GA. Anatomic and functional results of surgical repair after total perineal rupture at delivery. Surg Gynecol Obstet 1988; 166:121-124. 152. Venkatesh KS, Ramanujam PS, Larson DM, Haywood MA. Anorectal complications of vaginal delivery. Dis Colon Rectum 1989; 32:1039-1041. 153. M¿ller Bek K, Laurberg S. Risks of anal incontinence from subsequent vaginal delivery after a complete obstetric anal sphincter tear. Br J Obstet Gynaecol 1992; 99:724-726. 154. Laurberg S, Swash M, Henry MM. Delayed external sphincter repair for obstetric tear. Br J Surg 1988; 75:786-788. ---------------------------------------------------------------------------
--------------------------------------------------------------------------- Bob Woolley -- --------------------------------------------------------------------------- St. Paul, Minnesota
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