Perineal tear

Illustration of two perineal tears.

In obstetrics, a perineal tear is a spontaneous (unintended) laceration of the skin and other soft tissue structures which, in women, separate the vagina from the anus. Perineal tears mainly occur in women as a result of vaginal childbirth, which strains the perineum. Tears vary widely in severity. The majority are superficial and require no treatment, but severe tears can cause significant bleeding, long-term pain or dysfunction. A perineal tear is distinct from an episiotomy, in which the perineum is intentionally incised to facilitate delivery.

Anatomy

In a woman, the anus and the vaginal opening lie within the anatomical region known as the perineum. Each opening is surrounded by a wall, and the anal wall is separated from the vaginal wall by a mass of soft tissue including:

A perineal tear may involve some or all of these structures, which normally aid in supporting the pelvic organs and maintaining faecal continence.[2]

Classification

Tears are classified into four categories:[3][4]

Cause

In humans and some other primates, the head of the term fetus is so large in comparison to the size of the birth canal that term delivery is rarely possible without some degree of trauma.[6] As the head passes through the pelvis, the soft tissues are stretched and compressed. The risk of severe tear is greatly increased if the fetal head is oriented occiput posterior (face forward), if the mother has not given birth before or if the fetus is large.[7]

Prevention

Several techniques are used to reduce the risk of tearing, but with little evidence for efficacy. Antenatal digital perineal massage is often advocated, and may reduce the risk of trauma only in nulliparous women.[8] ‘Hands on’ techniques employed by midwives, in which the foetal head is guided through the vagina at a controlled rate have been widely advocated, but their efficacy is unclear.[9] Waterbirth and labouring in water are popular for several reasons, and it has been suggested that by softening the perineum they might reduce the rate of tearing. However, this effect has never been clearly demonstrated.[10] The ‘Epi-no birth trainer’, a relatively recent invention, is a device specifically designed to strengthen and stretch the perineum during pregnancy. In spite of some promising studies, systematic review has shown no effect on the rate of tearing or episiotomy.[11]

Prevalence

Over 85% of women having a vaginal birth sustain some form of perineal trauma, and 60-70% receive stitches.[12] A retrospective study of 8603 vaginal deliveries found a third degree tear had been clinically diagnosed in only 50 women (0.6%).[13] However, when the same authors used anal endosonography in a consecutive group of 202 deliveries, there was evidence of third degree tears in 35% of first-time mothers and 44% of mothers with previous children.[14] These numbers are confirmed by other researchers.[15]

Complications

First and second degree tears rarely cause long-term problems. Among women who experience a third or fourth degree tear, 60-80% are asymptomatic after 12 months.[16] Faecal incontinence, faecal urgency, chronic perineal pain and dyspareunia occur in a minority of patients, but may be permanent.[17] The symptoms associated with perineal tear are not always due to the tear itself, since there are often other injuries, such as avulsion of pelvic floor muscles, that are not evident on examination.[18]

Insurance Coverage

A study by the Agency for Healthcare Research and Quality (AHRQ) found that in 2011, first- and second-degree perineal tear was the most common complicating condition for vaginal deliveries in the U.S. among women covered by either private insurance or Medicaid.[19] Second-degree perineal laceration rates were higher for women covered by private insurance than for women covered by Medicaid.[20]

References

  1. ↑ Last, R. J. (1984). Anatomy Regional and Applied. London: Churchill Livingstone. p. 345. ISBN 0-443-02989-X.
  2. ↑ Finn, Martha; Bowyer, Lucy; Carr, Sandra; O'Connor, Vivienne; Vollenhoven, Beverley (2005). Women's Health: A Core Curriculum. Australia: Elsevier. ISBN 0-7295-3736-6.
  3. ↑ Taber's Cyclopedic Medical Dictionary tabers.com
  4. ↑ http://www.thewomens.org.au/PerinealTraumaAssessmentandRepair
  5. ↑ MDConsult mdconsult.com
  6. ↑ Rosenberg, Karen; Trevathan, Wenda (2003). "Birth, obstetrics and human evolution". BJOG: An International Journal of Obstetrics and Gynaecology 109 (11).
  7. ↑ Eskandar, O; Shet, D (February 2009). "Risk factors for 3rd and 4th degree perineal tear.". Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology 29 (2): 119–22. doi:10.1080/01443610802665090. PMID 19274544.
  8. ↑ Seehusen, DA; Raleigh, M (1 March 2014). "Antenatal perineal massage to prevent birth trauma.". American family physician 89 (5): 335–6. PMID 24695503.
  9. ↑ Wang, H; Jayasekara, R; Warland, J (12 March 2015). "The effect of "hands on" techniques on obstetric perineal laceration: A structured review of the literature.". Women and birth : journal of the Australian College of Midwives 28: 194–8. doi:10.1016/j.wombi.2015.02.006. PMID 25773668.
  10. ↑ Nutter, E.; Meyer, S.; Shaw-Battista, J.; Marowitz, A. (2014). "Waterbirth: an integrative analysis of peer-reviewed literature.". Journal of Midwifery & Women's Health 59 (3): 286–319. doi:10.1111/jmwh.12194. PMID 24850284.
  11. ↑ Brito, LG; Ferreira, CH; Duarte, G; Nogueira, AA; Marcolin, AC (8 April 2015). "Antepartum use of Epi-No birth trainer for preventing perineal trauma: systematic review.". International urogynecology journal 26: 1429–36. doi:10.1007/s00192-015-2687-8. PMID 25851585.
  12. ↑ Kettle, C., & Tohill, S. (2008). Perineal care. Clinical evidence, 2008.
  13. ↑ 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.
  14. ↑ Sultan A, Kamm MA, Hudson CN, Thomas JM, Bartram CI. Anal sphincter disruption during vaginal delivery. N Engl J Med 1993;329: 1905–1911.
  15. ↑ Fines M, Donnelly V, Behan M, O'Connell PR, O'Herlihy C. Effect of second vaginal delivery on anorectal physiology and faecal continence: a prospective study. Lancet 1999;354: 983–986.
  16. ↑ Toglia, Marc. "Repair of episiotomy and perineal lacerations associated with childbirth". UpToDate. Retrieved 22 May 2015.
  17. ↑ Fernando, RJ; Sultan, AH; Kettle, C; Radley, S; Jones, P; O'Brien, PM (June 2006). "Repair techniques for obstetric anal sphincter injuries: a randomized controlled trial.". Obstetrics and gynecology 107 (6): 1261–8. doi:10.1097/01.aog.0000218693.24144.bd. PMID 16738150.
  18. ↑ Lammers, K; Prokop, M; Vierhout, ME; Kluivers, KB; Fütterer, JJ (August 2013). "A pictorial overview of pubovisceral muscle avulsions on pelvic floor magnetic resonance imaging.". Insights into imaging 4 (4): 431–41. doi:10.1007/s13244-013-0261-9. PMID 23756995.
  19. ↑ Moore JE, Witt WP, Elixhauser A. (April 2014). "Complicating Conditions Associate With Childbirth, by Delivery Method and Payer, 2011.". HCUP Statistical Brief #173. Rockville, MD: Agency for Healthcare Research and Quality.
  20. ↑ Moore JE, Witt WP, Elixhauser A. (April 2014). "Complicating Conditions Associate With Childbirth, by Delivery Method and Payer, 2011.". HCUP Statistical Brief #173. Rockville, MD: Agency for Healthcare Research and Quality.
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