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ORIGINAL RESEARCH |
From the 1Academic Unit of Obstetrics and Gynecology, University Hospital of North Staffordshire, Staffordshire, United Kingdom; 2Mayday University Hospital, Croydon, Surrey, United Kingdom; 34Queen Elizabeth Hospital, Birmingham, United Kingdom; and 5Keele University, Staffordshire, United Kingdom.
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ABSTRACT |
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 ABSTRACT MATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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METHODS: Women who sustained third-degree (3b = greater than 50% external anal sphincter thickness, 3c = internal sphincter injury) or fourth-degree (including anorectal epithelium) perineal tears were randomly allocated to either immediate primary overlap or end-to-end repair. They were prospectively followed up for 12 months postrepair with serial questionnaires. The primary outcome was fecal incontinence at 12 months. Secondary outcomes were fecal urgency, flatus incontinence, perineal pain, dyspareunia, quality of life, and improvement of anal incontinence symptoms.
RESULTS: Thirty-two women were randomized to each group. At 12 months, 24% (6/25) in the end-to-end and none in the overlap group reported fecal incontinence (P = .009, relative risk [RR] 0.07, 95% confidence interval [CI] 0.00–1.21, number needed to treat 4.2). Fecal urgency at 12 months was reported by 32% (8/25) in the end-to-end and 3.7% (1/27) in the overlap group (P = .02, RR 0.12, 95% CI 0.02–0.86, number needed to treat 3.6). There were no significant differences in dyspareunia and quality of life between the groups. At 12 months, 20% (5/25) reported perineal pain in the end-to-end and none in the overlap group (P = .04, RR 0.08, 95% CI 0.00–1.45, number needed to treat 5). During 12 months, 16% (4/25) in the end-to-end and none in the overlap group reported deterioration of defecatory symptoms (P = .01).
CONCLUSION: Primary overlap repair of the external anal sphincter is associated with a significantly lower incidence of fecal incontinence, urgency, and perineal pain. When symptoms do develop, they appear to remain unchanged or deteriorate in the end-to-end group but improve in the overlap group.
LEVEL OF EVIDENCE: I
Anal incontinence incorporates a range of symptoms, including flatus incontinence, passive soiling, and incontinence of solid or liquid stool that is a social or hygienic problem.5 In addition, obstetric anal sphincter injury can be associated with fecal urgency,1,6 rectovaginal fistula,7 perineal pain, and dyspareunia.8 Because anal incontinence is a source of embarrassment and a social taboo, many women do not volunteer these symptoms but sadly "suffer in silence."9 Furthermore, anal incontinence caused by sphincter injury has been reported to be associated with very high cumulative costs for health services.10 Over the last decade, there has been a notable increase in litigation related to obstetric anal sphincter injury and its consequences.11
Anal sphincter injury sustained during childbirth has been traditionally repaired by obstetricians in the immediate postpartum period. However, it is concerning that 25–59% of women have persistent symptoms despite primary repair.12 Poor understanding of perineal anatomy and inadequate training in repair techniques are possible reasons for the high incidence of persistent symptoms.4 Furthermore, there is limited and inconsistent information in the literature relating to repair techniques, suture materials, antibiotics, laxatives, and the management of subsequent pregnancies after anal sphincter injury.4,12
Traditionally obstetric anal sphincter injuries are repaired by obstetricians as soon as possible after birth by using the end-to-end technique to reapproximate the torn ends of the external anal sphincter with either interrupted or figure-of-eight sutures.4 However, in cases of delayed or secondary anal sphincter repair when women present with fecal incontinence, colorectal surgeons prefer to reapproximate the disrupted ends of the external anal sphincter by using the overlap technique.4 Having observed colorectal surgeons carrying out this procedure, Sultan et al13 demonstrated that it was feasible to use the overlap technique for primary repair of the external anal sphincter. Furthermore, Sultan et al13 reported that the overlap technique, when compared with historical controls (repaired with the end-to-end technique), reduced anal incontinence from 40% to 8% and persistent anal sphincter defects from 85% to 15%. We carried out a comprehensive literature search on MEDLINE (January 1966 to November 31, 1998), EMBASE (January 1974 to November 31, 1998), and SciSearch (January 1974 to November 31, 1998) databases. The search terms used were "perin*," "anal sphincter AND tear*," "rupture*," "trauma," "damage," "injur* AND labor," "labour," "birth," "childbirth," "delivery," "obstetric* AND tear*," "rupture*," "injur*," "damage," "trauma." In addition, we searched conference proceedings of associations of obstetrics and gynecology, surgery, and coloproctology. No randomized controlled studies comparing these 2 techniques were available at the commencement of this study. The aim of our study was to undertake a randomized controlled trial to compare the overlap with the end-to-end method of primary external anal sphincter repair performed immediately after obstetric anal sphincter injury.
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MATERIALS AND METHODS |
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The study was designed as a parallel group randomized controlled study with minimization for parity, gestation, and mode of delivery using a customized computer package. It was programmed to minimize the possibility of unequal distribution of confounding factors between the 2 groups, which otherwise would have affected the outcome. Use of "minimization" rather than random permuted blocks for treatment allocation ensured that the 2 groups were similar and that confounding factors were evenly distributed. As stated by Pocock,15 the purpose of minimization "is to balance the marginal treatment totals for each level of patient factor." The customized computer randomization package, which was designed by the Birmingham Clinical Trials Unit (Birmingham, UK), was password-protected to ensure concealment of treatment allocation. Participants were randomly allocated to overlap or end-to-end repair of the external anal sphincter immediately after delivery, and they were blinded to the method of suturing.
The primary outcome measure was fecal incontinence at 12 months. Secondary outcome measures were fecal incontinence at six weeks, three and six months, fecal urgency, flatus incontinence, perineal pain, dyspareunia at six weeks, three, six and 12 months, and improvement of anal incontinence symptoms over the 12 month period following the procedure.
Two clinicians who were trained in both techniques carried out all of the repairs in the operating theater under regional or general anesthesia and in the lithotomy position as described by Sultan et al.13 All repairs were carried out within 3 hours of detecting the anal sphincter injury.
In the end-to-end technique, the torn anal epithelium was repaired using interrupted 3-0 standard polyglactin (Vicryl; Ethicon, Edinburgh, UK) sutures with knots tied within the anal canal (Fig. 2). If the internal anal sphincter was torn, it was repaired separately with interrupted 3-0 polydioxanone (PDS; Ethicon) sutures. The torn ends of the external anal sphincter were approximated and repaired with 2-3 mattress sutures using 3-0 PDS sutures. The vaginal mucosa and perineal muscles were repaired with continuous nonlocking 2-0 rapidly absorbed polyglactin (Vicryl Rapide; Ethicon) sutures, and the perineal skin was closed with subcuticular 2-0 rapidly absorbed polyglactin (Vicryl Rapide) sutures.16
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In the overlap technique, the torn anal epithelium and internal anal sphincter were repaired as described above using interrupted 3-0 standard polyglactin (Vicryl) and interrupted 3-0 polydioxanone (PDS) sutures, respectively (Fig. 3). After identification of the torn ends of the external anal sphincter, the outer surface of the sphincter was mobilized from the surrounding tissue if necessary. If the external anal sphincter was incompletely torn (> 50%), the remaining fibers were divided so that the torn ends could be fully overlapped. The first row of sutures was inserted about 1.5 cm from one side of the torn edge of external anal sphincter (open arrow, Fig. 3) and carried through to within 0.5 cm of the other edge of the torn external anal sphincter. A second row of sutures (small arrows, Fig. 3) was inserted to attach the loose end of the overlapped muscle.13 The vaginal mucosa and perineal skin were closed as described in the end-to-end method.
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All women received intra-operative intravenous antibiotics and post operative oral antibiotics for seven days and a bulking agent (Ispaghula husk) and a stool softener (Lactulose) for 14 days post-operatively. There were no dietary restrictions during the post-operative period.
The women were followed with self-administered questionnaires at 6 weeks, and 3, 6, and 12 months after the repair. These questionnaires included the modified Wexner anal incontinence scoring system,17 in which the highest score of 24 refers to complete incontinence and 0 refers to complete continence. In addition, the questionnaires contained the Fecal Incontinence Quality of life Scale,18 which has 4 separate scales: Life Style, Coping/Behavior, Depression/Self-Perception, and Embarrassment. A second set of questionnaires was sent to those women who did not respond, and they were also reminded by a telephone call.
When we were designing this study, there were no pre-existing published randomized studies comparing primary overlap with end-to-end external anal sphincter repair techniques. Therefore, the sample size was based on a feasibility study conducted by Sultan et al,13 in which 32 women had overlap repairs of the external anal sphincter. The study reported that 8% of the participants experienced anal incontinence in comparison with 47% in an historical group from a previous study (n = 34) who underwent end-to-end repair of the external anal sphincter.1 Based on the above figures, the sample size was calculated by using NCSS-PASS 6.0 (J. L. Hintze, Kaysville, UT) software. A total sample size of 48 women (24 in each arm) would allow detection of a change in the primary outcome of fecal incontinence from 47% to 8%, with greater than 90% power and 2-sided 5% significance. To accommodate participants lost to follow-up at 12 months, we planned to recruit at least 60 women before the end of the recruitment period (November 30, 2000).
The primary statistical analyses were carried out on an "intention-to-treat" basis. All data were initially entered in a customized Microsoft 1997 Excel database and then imported into NCSS (NCSS 2001) and StatXact 4 (StatXact 4 Cytel, Cambridge, MA) for statistical analysis. StatXact 4 is a special statistical program designed to calculate exact P values when the frequencies are small and the 
2 significance test was carried out on binary and nominal data (exact P values are quoted to allow for small frequencies). The Mann-Whitney test was used for ordered response categories. Relative risks were calculated with Review Manager 4.2.7 software (Cochrane Collaboration, Oxford, UK).
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RESULTS |
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Twenty five women (78%) in the overlap group and 27 women (81%) in the end-to-end group were primiparous.
The number of women recruited with third-degree (grades 3b and 3c) and fourth-degree perineal tears were comparable in both groups (Table 1). In 4 of 25 women in the overlap group, some fibers of the torn external anal sphincter were divided to achieve complete overlap. Maternal age, period of gestation, mode of delivery, birth weight, and head circumferences between the 2 intervention groups are shown in Table 1.
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The median operating time in the overlap group was 38 minutes (range 15–70) compared with 28 minutes (range 15–55) in the end-to-end group (P = .003, Mann-Whitney test). The median estimated blood loss in the overlap group was 260 mL (range 100–600) compared with 100 mL (range 100–450) in the end-to-end group (P = .05, Mann-Whitney test). None of the 64 women required blood transfusion or developed wound dehiscence, fistula formation, or suture migration.
Compared with the overlap group, there was a statistically significant proportion of women in the end-to-end group who reported fecal incontinence at 12 months (Table 2). A statistically significant proportion of women in the end-to-end group reported fecal incontinence at 3 and 6 months (Table 3). In the end-to-end group, there was an increase in fecal incontinence symptoms from 6 weeks to 3 months, with a decrease afterward. In Table 3 the decrease of fecal incontinence from 3 to 6 months by 3 patients was not attributed to the 3 women who did not return the questionnaire.
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Compared with the overlap group, there was a statistically significant proportion of women in the end-to-end group who reported fecal urgency at 6 and 12 months. There was no difference in flatus incontinence between the 2 groups at 3, 6, and 12 months (Tables 2 and 3). There was no difference in the median incontinence scores at 3 and 6 months. The median incontinence score at 12 months in the end-to-end group was 1 (range 0–9) compared with 0 (range 0–5) in the overlap group (P = .05, Mann-Whitney test).
There was no significant difference in perineal pain from 6 weeks up to 6 months (Table 3). However, at 12 months a significant proportion of women in the end-to-end group reported perineal pain (Table 2). There was no significant difference in dyspareunia between the 2 groups up to 12 months (Tables 2 and 3). There were no significant differences between the 2 techniques in terms of the mean Life Style, Coping/Behavior, Depression/Self-Perception, and Embarrassment scales of the Fecal Incontinence Quality of Life Scale.18
Compared with the end-to-end group, a significant proportion of women (P = .01) in the overlap group reported an improvement in symptoms of anal incontinence from 6 weeks to 12 months (Table 4). None of the patients in either group complained of difficulty in bowel evacuation or dyschezia. There was no correlation between anal incontinence and the mode of delivery.
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DISCUSSION |
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There are 2 randomized controlled studies comparing the primary overlap and end-to-end repair techniques19,20. Fitzpatrick et al19 compared the same 2 techniques but followed participants to only 3 months postrepair. Fitzpatrick and colleagues reported that 49% of the overlap group, compared with 58% of women in the end-to-end group, had alteration in fecal continence. Power calculation of this study was based on the identification of a 30% "symptomatic" difference between the 2 methods of repair, with a 90% probability. In addition there were methodological differences between the study of Fitzpatrick et al19 and our study, in that they included partial (grade 3a) tears of the external anal sphincter in their randomization and did not identify and repair the internal anal sphincter. The women were also prescribed codeine-based constipating agents for 3 days, followed by a laxative regimen for 5 days or until defecation had occurred, which was different from our postoperative management. Fitzpatrick and colleagues19 found no statistical difference in alteration in fecal continence symptoms at 3 months between the groups and therefore recommended the end-to-end technique of external anal sphincter repair because of its simplicity.
Garcia et al20 also performed a randomized trial of the 2 techniques and took great care to include only complete ruptures of the external anal sphincter (full thickness 3b, 3c, and fourth-degree tears). There were 23 women in the end-to-end group and 18 in the overlap group. Unfortunately, only 15 and 11 women, respectively, returned for follow-up, which occurred at only 3 months. No significant difference was found between the groups in terms of symptoms of fecal incontinence or transperineal ultrasound findings. However, the authors acknowledged that the major limitations of their study were that randomization was inaccurate and that their study was underpowered. Nevertheless, the findings of both of these studies concur with our findings in that the continence scores were not significantly different at 3 and 6 months, but reached statistical significance at 12 months.
In terms of anal incontinence symptoms, we found that a significant proportion of women in the end-to-end group reported fecal incontinence at 3, 6, and 12 months. Moreover, we found a significant improvement of anal incontinence symptoms during the 12-month period in the overlap group, with no women showing deterioration (Table 4). In the end-to-end group, 32% reported no change in anal incontinence symptoms, whereas 16% reported symptom deterioration between 6 weeks and 12 months. This highlights the need for longer term follow-up. However, it remains to be established why the overlap technique is associated with superior results. It could be postulated that, to perform an overlap repair, the full length of the external anal sphincter has to be identified, whereas the end-to-end method can be performed without the full length being identified, which may result in a deficient repair.13 Secondly, because the anal sphincter is normally under tonic contraction, the end-to-end technique may be more vulnerable to ischemia (particularly with figure-of-eight sutures) due to retraction of the apposed muscles. Conversely, the overlap technique allows for some retraction while still maintaining apposition.
In our study, if the internal anal sphincter was torn, it was repaired separately. The internal anal sphincter is a smooth muscle and contributes to most of the resting anal pressure. Internal anal sphincter dysfunction is usually associated with symptoms of incontinence of flatus and passive soiling. However, because combined external and internal anal sphincter injuries can occur, mixed symptoms may develop. In contrast, when colorectal surgeons perform a secondary repair for fecal incontinence, they find it difficult to identify and repair a scarred internal anal sphincter, although one study has shown good results.21
Fecal urgency and fecal urge incontinence can be more distressing than passive fecal incontinence.22 Women with fecal urgency are continually inhibited by the threat of fecal urge incontinence. It has been reported that many women with fecal urgency were not willing to put their continence to the test.6 This study has clearly demonstrated the advantage of the primary overlap repair in terms of fecal urgency.
Compared with the end-to-end technique, the primary overlap technique was associated with a significantly longer median operating time (28 minutes versus 38 minutes, P = .03). However, this could be attributed to more dissection associated with overlap technique compared with the end-to-end technique. The median estimated blood loss was marginally higher (100 mL versus 260 mL, P = .05) with the overlap technique, but there was no significant change in the hematocrit, and none of the participants required a blood transfusion.
Williams23 reported that suture migration with the use of permanent sutures such as Prolene (Ethicon) occurs in one third of women after primary repair of obstetric anal injury. In our study no woman complained of suture migration or required suture removal, and none developed wound dehiscence. We did, however, ensure that the PDS suture ends were cut short and carefully buried by overlying perineal muscles. It is difficult to offer an explanation as to why more women in the end-to-end group reported perineal pain at 12 months. It is acknowledged that denervation and reinnervation may play a role, but we have not performed any invasive neurophysiological tests.
We calculated the sample size based on 2 comparable, but separate, observational studies at the commencement of the study1,13 and required 48 women. Although we took every possible step to maximize compliance, only 52 (81%) of the original 64 women returned the questionnaire at 12 months.
In most clinical settings in the United Kingdom, when obstetric anal sphincter injuries are diagnosed, they are repaired by middle-grade obstetric trainees with variable experience.4 However, in this study we specifically aimed to compare the outcome of 2 techniques and therefore restricted the trained operators to two. Having established the outcomes, we have now commenced a more pragmatic randomized controlled study comparing the 2 techniques, with stratification for operator experience. We may then be in a position to establish whether training needs reappraisal.
This randomized study has shown that primary overlap repair of the external sphincter is associated with a significantly lower incidence of fecal incontinence, urgency, and perineal pain. Furthermore, when symptoms do develop, they appear to remain unchanged or deteriorate in the end-to-end group but improve in the overlap group. Because an increasing number of women are requesting elective cesarean delivery out of fear of perineal trauma and its consequences,24 it is important that we are able to reassure them that, when obstetric anal sphincter injury is identified, it will be repaired by a skilled clinician using an evidence-based suture technique, thus minimizing the associated morbidity.
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Footnotes |
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We acknowledge the contribution of the late Professor Richard Johanson, who conceived and designed this study but died while the study was underway.
Findings of this study were presented at the Joint Meeting of the International Continence Society and the International Urogynecological Association, Paris, France, August 23–27, 2004.
Corresponding author: Ruwan J Fernando, MD, MRCOG, Subspecialty Trainee in Urogynecology, Mayday University Hospital, Croydon, Surrey, CR7 7YE, United Kingdom; e-mail: ruwanfernando{at}hotmail.com.
doi:10.1097/01.AOG.0000218693.24144.bd
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REFERENCES |
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2. Fenner DE, Genberg B, Brahma P, Marek L, DeLancey JO. Fecal and urinary incontinence after vaginal delivery with anal sphincter disruption in an obstetric unit in the United States. Am J Obstet Gynecol 2003;189:1543–50.[Medline]
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12. Sultan AH, Thakar R. Lower genital tract and anal sphincter trauma. Best Pract Res Clin Obstet Gynecol 2002;16:99–115.
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16. Kettle C, Hills RK, Jones P, Darby L, Gray R, Johanson R. Continuous versus interrupted perineal repair with standard or rapidly absorbed sutures after spontaneous vaginal birth: a randomized controlled trial. Lancet 2000;359:2217–23.
17. Vaizey CJ, Carapeti E, Cahill JA, Kamm MA. Prospective comparison of faecal incontinence grading system. Gut 1999;44:77–80.
18. Rockwood TH, Church JM, Fleshman JW, Kane RL, Mavrantonis C, Thorson AG, et al. Fecal incontinence Quality of Life Scale: quality of life instrument for patients with fecal incontinence. Dis Colon Rectum 2000;43:9–16.[Medline]
19. Fitzpatrick M, Behan M, O’Connell PR, O’Herlihy C. A randomized clinical trial comparing primary overlap with approximation repair of third degree obstetric tears. Am J Obstet Gynecol 2000;183:1220–4.[Medline]
20. Garcia V, Rogers RG, Kim SS, Hall RJ, Kammerer-Doak DN. Primary repair of obstetric anal sphincter laceration: a randomized trial of two surgical techniques. Am J Obstet Gynecol 2005;192:1697–701.[Medline]
21. Meyenberger C, Bertschinger P, Zala GF, Buchmann P. Anal sphincter defects in fecal incontinence: correlation between endosonography and surgery. Endoscopy 1996;28:217–24.[Medline]
22. Gee AS, Durdey P. Urge incontinence of faeces is a marker of severe external anal sphincter dysfunction. Br J Surg 1995;82:1179–82.[Medline]
23. Williams A. Third degree perineal tears: risk factors and outcome after primary repair. J Obstet Gynaecol 2003;23:611–14.[Medline]
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