Irreversible traumatic distension of the levator hiatus


Authors’ Reply


Thank you for asking me to comment on Dr Kapoor’s letter.1 He raises several interesting questions regarding our study recently published in BJOG.2 The percentage of episiotomy in the 32 women diagnosed with levator avulsion was 41% (13/32). A total of 56% (18/32) had perineal tears of any degree, and 22% (7/32) sustained a major perineal tear. The corresponding figures for the group of women diagnosed with levator microtrauma was 25% (14/57), 47% (27/57) and 7% (4/57), respectively. Forty-two women had a normal vaginal delviery, and 11 had a vacuum and four had a forceps delivery.

During labour, maternal expulsive efforts and the force exerted by uterine contractions during the descent of the fetal head may potentially lead to vascular, neuromuscular and connective tissue changes.3–6 Muscular atrophy, a reduction in function and/or alterations in pelvic floor distensibility may ensue. Dharmesh S Kapoor has rightly pointed out that the early postpartum follow-up (median 4.08 months) in our series is a limitation. However, we have recently analysed the first 161 patients returning for a 2–3 year follow-up, and there were no significant changes in hiatal dimension on Valsalva compared to the 3–6 month follow-up. The suggestion that a disrupted perineum may be a possible mechanism of irreversible traumatic overdistension of the hiatus is very interesting. Future work should examine the relationship between a deficient perineum with a widened urogenital hiatus and hiatal distensibility. In our study we did not find any significant association between episiotomy (P = 0.75), all perineal tears (P = 0.26) and major perineal tears (P = 0.26) with levator microtrauma.

In a previous response7 to a letter from Dr Quinn8 we have suggested, based on current evidence, that vacuum delivery instead of forceps delivery, restriction of the length of second stage and epidural analgesia may be considered to potentially reduce or even prevent levator injury. With regard to the questions on episiotomy, we do not know whether episiotomy and the timing of the procedure may help prevent levator injury. A randomised controlled study would be needed to answer these questions.