Dr Chapron et al.1 have demonstrated a predilection of deeply infiltrating endometriosis for the left uterosacral ligament (in the posterior half of the pelvis). They will be aware that there is also a predilection for disruption of the right paravaginal sulcus and right pubococcygeus in many patients with cystocoele and urinary stress incontinence in the anterior pelvis (Fig. 1). Reinnervation of the myometrium following primary denervation at vaginal delivery is also asymmetrical and is frequently associated with chronic pelvic pain, menstrual disturbances and secondary dysmenorrhoea2. Each may be a consequence of the mechanics of vaginal delivery.


Figure 1. Axial section at the level of the proximal urethra (u). The right superior vaginal sulcus has been avulsed from the arcus tendineus fasciae pelvis, and, the right pubococcygeus has been avulsed from its pubic attachment. Unilateral, left sided paravaginal injuries in the anterior half of the pelvis producing cystocoele and urinary stress incontinence are uncommon (u = urethra; v = vagina; r = rectum; pc = pubococcygeus).

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Severe rectovaginal endometriosis frequently occurs in patients with uterine hyperstimulation following prostaglandin pessaries for induction of labour. Avulsion of uterosacral ligaments from their primary insertions into the posterior vaginal wall and rectovaginal septum not only causes significant primary damage but also disrupts the nerve bundles in the uterosacral ligaments3. Early retrograde menstruation while the injury is improving deposits endometrium, but it may be medium term reinnervation that is associated with the refractory pain. Similar reinnervation occurs in the bladder, uterus and vulva following a primary denervatory episode to account for other common sensory pelvic syndromes2. Lesser degrees of intrapartum damage may account for other patterns of parous endometriosis and their characteristic distributions. Ectopic endometrium may not account for very much of the pain in parous ‘endometriosis’.


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  2. References
  • 1
    Chapron C, Fauconnier A, Dubuisson JB, Vieira M, Bonte H, Vacher-Laveu MC. Does deep endometriosis infiltrating the uterosacral ligaments present an asymmetric lateral distribution Br J Obstet Gynaecol 2001;108: 10211024.
  • 2
    Quinn MJ. Obstetric denervation—gynaecological reinnervation. Am J Obstet Gynecol 2002. In press.
  • 3
    Campbell RM. The anatomy and histology of the sacrouterine ligaments. Am J Obstet Gynecol 1950;59: 112.