Gonzalez-Díaz E, Moreno Cea L, Fernández Corona A
Pelvic Floor Unit, Department of Obstetrics and Gynaecology, Complejo Asistencial Universitario of León (CAULE), C/ Altos de Nava S/N, 24080, León, Spain,
Int Urogynecol J. 2015 Feb;26(2):235-42. doi: 10.1007/s00192-014-2491-x. Epub 2014 Sep 17.
The objective of this study was to investigate the association between the trigonometric properties of episiotomy in operative vaginal delivery (OVD) and obstetric anal sphincter injuries (OASIS).
The study included 72 primiparous women who had an OVD and episiotomy. Cases (n = 36) had sustained OASIS at birth, while controls (n = 36) had not. The groups were matched for instrumental delivery. The episiotomy scar was identified and its trigonometric characteristics were measured at 8-12 weeks postpartum. Data were analysed using conditional logistic analysis.
The angle of episiotomy behaves as a factor associated with anal sphincter injury, so women with a mediolateral episiotomy and an angle greater than 20° have an 87% less risk of having an OASIS (odds ratio 0.13, 95% confidence interval 0.03-0.58). The study showed that scarred episiotomies at 8-12 weeks after OVD with an angle ≤ 20°, depth and distance between the episiotomy and anus ≤ 15 mm, total upper triangle perimeter ≤ 75 mm, para-anal triangle perimeter ≤ 15 mm and areas between scar and midline ≤ 250 mm(2) were significantly associated with higher risk of OASIS.
When a mediolateral episiotomy is performed in OVD the technique has a strong effect on the occurrence of OASIS. Additional research is needed to determine if the optimal technique for mediolateral episiotomies produces less OASIS than deferring the performance of episiotomy.
本研究旨在探讨手术阴道分娩（OVD）时会阴切开术的三角特性与产科肛门括约肌损伤（OASIS）之间的关联。
该研究纳入了72例接受OVD与会阴切开术的初产妇。病例组（n = 36）在分娩时发生了OASIS，而对照组（n = 36）未发生。两组在器械助产方面进行了匹配。在产后8 - 12周识别会阴切开术瘢痕并测量其三角特征。使用条件逻辑分析对数据进行分析。
会阴切开术的角度是与肛门括约肌损伤相关的一个因素，因此采用会阴侧切且角度大于20°的女性发生OASIS的风险降低87%（优势比0.13，95%置信区间0.03 - 0.58）。研究表明，OVD后8 - 12周时，角度≤20°、会阴切开术与肛门之间的深度和距离≤15 mm、上三角总周长≤75 mm、肛门旁三角周长≤15 mm以及瘢痕与中线之间的面积≤250 mm²的会阴切开术瘢痕与发生OASIS的较高风险显著相关。
在OVD中进行会阴侧切时，该技术对OASIS的发生有很大影响。需要进一步研究以确定会阴侧切的最佳技术是否比推迟会阴切开术产生更少的OASIS。
