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ORIGINAL RESEARCH |
From the Department of Obstetrics and Gynecology, the Cleveland Clinic Foundation, Cleveland, Ohio.
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ABSTRACT |
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 ABSTRACT MATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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METHODS: An obstetrics and gynecology resident, a perinatologist, and a urogynecologist evaluated 7 obstetrics textbooks by using a standardized abstraction form that delineated descriptions of anatomy and physiology, episiotomy use, and perineal trauma prevention and repair.
RESULTS: Two textbooks briefly described anal sphincter anatomy, but none provided a detailed discussion of the relative contribution of anatomic components to continence. Four textbooks discussed the evidence for and against midline or mediolateral episiotomy, and 6 advised against routine episiotomy. Six textbooks described grading lacerations, but only one described detailed repair techniques for all grades. Two textbooks discussed techniques to reduce perineal trauma at the time of delivery. Only one textbook discussed the need to reapproximate the normal anal sphincter anatomy during perineal repair.
CONCLUSION: Although most textbooks accurately reflect current literature regarding routine episiotomy, there is limited discussion of advantages and disadvantages of various types of episiotomy and little offered regarding prevention and repair of perineal trauma at delivery.
LEVEL OF EVIDENCE: III
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MATERIALS AND METHODS |
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ABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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A standard abstraction form consisting of 34 questions was developed for assessment of descriptions of anatomy and physiology, episiotomy use, and perineal trauma prevention and repair. A perinatologist, an obstetrics and gynecology resident, and a urogynecologist used the abstraction form to evaluate each textbook. When responses varied, the response given by the majority of reviewers was used for results and statistical analysis. If there was no clear majority, the question was reviewed by a fourth reviewer (a urogynecologist) and a consensus reached.
Statistical analyses included descriptive point estimates of the number of textbooks that addressed each item, with 95% confidence intervals calculated by using the modified Wald method. This study was granted exempt status from our Institutional Review Board.
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RESULTS |
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ABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Only 2 textbooks, one published in 2003 and one published in 2001, discussed the risk factors associated with perineal laceration and episiotomy. Two textbooks, one published in 2000 and one in 2003, included a discussion of techniques to reduce perineal trauma at the time of delivery. One textbook discussed both perineal massage during labor and a "hands-off" approach, defined as doing nothing to the perineum, as methods of reducing perineal trauma.12 The other textbook recommended preventing tears by "keeping the baby’s head well flexed until the occiput passes beyond the suprapubic arch."11 These questions were included for qualitative purposes and were not aggregated for statistical analysis.
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DISCUSSION |
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ABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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We searched MEDLINE and Cochrane databases from 1966 to 2005 to identify literature pertaining to anal sphincter anatomy, use of episiotomy, and episiotomy and vaginal laceration repair.
Review of the literature shows that anal sphincter anatomy and the mechanism of anal continence has been clearly defined. In 1997, DeLancey et al13 delineated the spatial relationships of the internal and external anal sphincters, specifically in relation to midline obstetric lacerations. They stated that the average length of the external anal sphincter is 2 cm and of the internal anal sphincter is approximately 3 cm; the sphincters typically have a 17-mm overlap. The internal sphincter consistently lies between the external sphincter and the anal mucosa.
Anal continence is maintained through a complex interaction of visceral and somatic muscles, nerves, and soft tissue. Studies from the 1960s and 1970s have shown that the internal sphincter accounts for 70–85% of resting tone.14,15 Although the external anal sphincter is a voluntary muscle, it does have some continuous tone. It contributes to continence mainly during times of increased rectal pressure, such as coughing and straining. Damage to pelvic nerves or direct muscle injury during childbirth can interfere with the anal continence mechanism, leading to symptoms of fecal urgency and anal incontinence, and therefore injuries to both sphincters are clinically relevant.16
Current texts offer little space to explain the levator ani and structures that insert on the perineal body. In 1999, DeLancey et al17 described the role of the perineal body in supporting the lower part of the vagina. The perineal body and distal vagina are anchored laterally and anteriorly to the ischiopubic rami by the perineal membrane. Perineal trauma leading to separation of the perineal body from the perineal membrane results in perineal descent and can contribute to defecatory dysfunction.
Although the decisions about when to perform episiotomy and which type of episiotomy to perform have not been clearly determined, our review shows that many textbooks do not accurately discuss the current literature available in some areas. The majority of textbooks stated that episiotomy should not be performed routinely. The recommendation against routine episiotomy use is supported by level I evidence, initially published in 1993 and 1994.3,18 A Cochrane review of episiotomy published in 2000 confirms this recommendation.19 It is interesting that some textbooks state that mediolateral episiotomy is more painful than midline episiotomy. There is only 1 published trial that attempts to address pain following each procedure.20,21 Preliminary conclusions suggested that mediolateral episiotomy may be more painful than midline episiotomy, but there was potential selection bias, and the methodologic quality was such that it was excluded from the recent Cochrane review noted above. Of note, the textbook published in 2003 suggested that current data does not support the conclusion that mediolateral episiotomy causes more pain and dyspareunia.8
From 1997 to 2001, 3 studies were published that demonstrated that midline episiotomy places the patient at higher risk of anal sphincter injury than mediolateral episiotomy. There are no clear data at this time that show which type of episiotomy is preferable and which type of episiotomy is associated with more pain. Notably, much of the investigation on this topic has come in recent years and therefore would not have been available for inclusion in many of the textbooks evaluated.
Although it is recognized that second-degree lacerations are more commonly seen than other degrees of trauma, it is important to have detailed reference material for repair of more significant perineal trauma. This will become more important in the future because fourth-degree lacerations are becoming less common, and graduating residents’ experience in repairing them is declining.2
Very little evidence exists for the proper repair of perineal trauma immediately postpartum. In a 1998 report of a 2-stage repair where the skin was left unsutured, Gordon et al22 found less pain and dyspareunia at 3 months and 1 year and no apparent disadvantages with the 2-stage repair. More research is needed in this area.
Techniques for repair of anal sphincter laceration have also been studied. In a randomized clinical trial published in 2000 that compared end-to-end approximation and primary overlapping sphincteroplasty for repair of third-degree lacerations, outcomes were noted to be similar in both groups.23 It is interesting to note, however, that two thirds of women had ultrasonographic evidence of residual anal sphincter damage irrespective of the method of repair. A recent 2005 review, published after all textbooks reviewed for this study, found that synthetic absorbable suture is associated with decreased short-term perineal pain and decreased analgesia use compared with plain or chromic catgut (level I evidence).37
Review of the literature finds several studies published between 1997 and 2001 that attempted to delineate the risk factors for anal sphincter laceration at the time of vaginal delivery. These and prior publications found nulliparity, postmaturity, fetal macrosomia, and episiotomy to be associated with increased rates of sphincter involvement at the time of delivery. In addition, operative vaginal deliveries have been implicated as a risk factor for sphincter laceration. Although the bulk of investigation on this topic was performed from 1998 to 2002, two studies examined these risk factors before publication of any of the obstetrics textbooks that we reviewed.27,28
There are limited data available from randomized controlled trials regarding prevention of perineal trauma. As mentioned above, limiting the use of episiotomy and operative vaginal delivery (specifically forceps) can decrease the incidence of perineal trauma (level I evidence).29 There is also level I evidence from 3 randomized, controlled trials including over 1,500 women that perineal massage in the weeks before delivery can decrease perineal trauma in nulliparous women. These studies were published between 1994 and 1999, yet none of the textbooks that we assessed discussed this technique. Further studies have found no benefit from support of infant head flexion, birthing position, or method of pushing regarding perineal trauma.29,33–36
Our study has notable limitations. First, our sample size is small. We attempted to study the most commonly used textbooks, but certainly our findings may not be generalizable to all obstetrics textbooks. Second, we used reviewers from various specialties and levels of expertise for this study. We found that some items from the abstraction form (eg, "This book provides a detailed discussion of internal and external sphincter anatomy") had varied responses based on the individual’s pre-existing knowledge base. By including an obstetrics and gynecology resident, a perinatologist, and a urogynecologist, we aimed to decrease this bias and make the results more generalizable to those who would use these textbooks as reference material.
Although we recognize that much of the literature regarding type of episiotomy, suture material, and prevention of perineal trauma has been published in proximity to the publication dates of the most recent editions of these 7 commonly used textbooks, several prior studies were not necessarily reflected in the pages of the current textbooks. Most textbooks accurately reflect the current literature regarding the use of routine episiotomy, but there is limited discussion of advantages and disadvantages of various types of episiotomy that is drawn from current evidence-based literature.
As educators of the next generation of obstetricians and gynecologists, we need to make a concentrated effort toward formal instruction in the repair of perineal trauma occurring at delivery. Pelvic surgeons familiar with anal sphincter and perineal anatomy and physiology should contribute to these chapters of obstetrics textbooks. Finally, editors should be critical of the accuracy of the content of chapters devoted to this subject.
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Footnotes |
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doi:10.1097/01.AOG.0000196502.33265.a4
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REFERENCES |
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2. McLennan MT, Melick CF, Clancy SL, Artal R. Episiotomy and perineal repair: an evaluation of resident education and experience. J Reprod Med 2002;47:1025–30.[Medline]
3. Routine vs selective episiotomy: a randomised controlled trial. Argentine Episiotomy Trial Collaborative Group. Lancet 1993;342:1517–8.[Medline]
4. Bodner-Adler B, Bodner K, Kimberger O, Wagenbichler P, Mayerhofer K. Management of the perineum during forceps delivery: association of episiotomy with the frequency and severity of perineal trauma in women undergoing forceps delivery. J Reprod Med 2003;48:239–42.[Medline]
5. Sultan AH, Kamm MA, Hudson CN. Obstetric perineal trauma: an audit of training. J Obstet Gynaecol 1995;15:19–23.
6. Beck WW. Obstetrics and gynecology. The National Medical Series for Independent Study. 4thed. Baltimore (MD): Lippincott Williams & Wilkins; 1997.
7. DeCherney AH, Nathan L. Current obstetric & gynecologic diagnosis & treatment. 9th ed. New York (NY): Lange Medical Books/McGraw-Hill; 2003.
8. Gabbe SG, Niebyl JR, Simpson JL. Obstetrics: normal and problem pregnancies. 4th ed. New York (NY): Churchill Livingstone; 2002.
9. Hacker NF, Moore JG. Essentials of obstetrics and gynecology. 3rd ed. Philadelphia (PA): W.B. Saunders; 1998.
10. Cunningham FG, Williams JW. Williams obstetrics. 21st ed. New York (NY): McGraw-Hill; 2001.
11. Danforth DN, Scott JR. Danforth’s obstetrics and gynecology. 9th ed. Philadelphia (PA): Lippincott Williams & Wilkins; 2003.
12. Enkin M. A guide to effective care in pregnancy and childbirth. 3rd ed. Oxford (UK): Oxford University Press; 2000.
13. Delancey JO, Toglia MR, Perucchini D. Internal and external anal sphincter anatomy as it relates to midline obstetric lacerations. Obstet Gynecol 1997;90:924–7.[Abstract]
14. Duthie HL, Watts JM. Contribution of the external anal sphincter to the pressure zone in the anal canal. Gut 1965;28:64–8.
15. Frenckner B, Euler CV. Influence of pudendal block on the function of the anal sphincters. Gut 1975;16:482–9.
16. Sultan AH, Kamm MA, Hudson CN, Thomas JM, Bartram CI. Anal-sphincter disruption during vaginal delivery. N Engl J Med 1993;329:1905–11.
17. DeLancey JO. Structural anatomy of the posterior pelvic compartment as it relates to rectocele. Am J Obstet Gynecol 1999;180:815–23.[Medline]
18. Klein MC, Gauthier RJ, Robbins JM, Kaczorowski J, Jorgensen SH, Franco ED, et al. Relationship of episiotomy to perineal trauma and morbidity, sexual dysfunction, and pelvic floor relaxation. Am J Obstet Gynecol 1994;171:591–8.[Medline]
19. Carroli G, Belizan J. Episiotomy for vaginal birth (Cochrane Review). In: The Cochrane Library, Issue 2, 2000. Oxford: Update Software.
20. Coats PM, Chan KK, Wilkins M, Beard RJ. A comparison between midline and mediolateral episiotomies. Br J Obstet Gynaecol 1980;87:408–12.[Medline]
21. Werner CH, Schuler W, Meskendal I. Midline episiotomy versus mediolateral episiotomy. A randomized prospective study. Proceedings of 13th World Congress of Gynecology and Obstetrics (FIGO), Singapore 1991. Int J Gynaecol Obstet 1991; Book 1:33.
22. Gordon B, Mackrodt C, Fern E, Truesdale A, Ayers S, Grant A. The Ipswich Childbirth Study: 1. A randomised evaluation of two stage postpartum perineal repair leaving the skin unsutured. Br J Obstet Gynaecol 1998;105:435–40.[Medline]
23. 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]
24. Zetterstrom J, Lopez A, Anzen B, Norman M, Holmstrom B, Mellgren A. Anal sphincter tears at vaginal delivery: risk factors and clinical outcome of primary repair. Obstet Gynecol 1999;94:21–8.
25. de Leeuw JW, Struijk PC, Vierhout ME, Wallenburg HC. Risk factors for third degree perineal ruptures during delivery. BJOG 2001;108:383–7.[Medline]
26. Poen AC, Felt-Bersma RJ, Dekker GA, Deville W, Cuesta MA, Meuwissen SG. Third degree obstetric perineal tears: risk factors and the preventive role of mediolateral episiotomy. Br J Obstet Gynaecol 1997;104:563–6.[Medline]
27. Sultan AH, Kamm MA, Hudson CN, Bartram CI. Third degree obstetric anal sphincter tears: risk factors and outcome of primary repair. BMJ 1994;308:887–91.
28. Combs CA, Robertson PA, Laros RK Jr. Risk factors for third-degree and fourth-degree perineal lacerations in forceps and vacuum deliveries. Am J Obstet Gynecol 1990;163:100–4.[Medline]
29. Eason E, Labrecque M, Wells G, Feldman P. Preventing perineal trauma during childbirth: a systematic review. Obstet Gynecol 2000;95:464–71.
30. Labrecque M, Marcoux S, Pinault JJ, Laroche C, Martin S. Prevention of perineal trauma by perineal massage during pregnancy: a pilot study. Birth 1994;21:20–5.[Medline]
31. Labrecque M, Eason E, Marcoux S, Lemieux F, Pinault JJ, Feldman P, et al. Randomized controlled trial of prevention of perineal trauma by perineal massage during pregnancy. Am J Obstet Gynecol 1999;180:593–600.[Medline]
32. Shipman MK, Boniface DR, Tefft ME, McCloghry F. Antenatal perineal massage and subsequent perineal outcomes: a random-ised controlled trial. Br J Obstet Gynaecol 1997;104:787–91.[Medline]
33. McCandlish R, Bowler U, van Asten H, Berridge G, Winter C, Sames L, et al. A randomised controlled trial of care of the perineum during second stage of normal labour. Br J Obstet Gynaecol 1998;105:1262–72.[Medline]
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35. Parnell C, Langhoff-Roos J, Iversen R, Damgaard P. Pushing method in the expulsive phase of labor. A randomized trial. Acta Obstet Gynecol Scand 1993;72:31–5.[Medline]
36. Thomson AM. Pushing techniques in the second stage of labour. J Adv Nurs 1993;18:171–7.[Medline]
37. Kettle C, Johanson RB. Absorbable synthetic versus catgut suture material for perinatal repair (Cochrane Review). In: The Cochrane Library, Issue 4, 2005. Oxford: Update Software.
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