Petros P E, Ulmsten U I
Department of Gynaecology, Royal Perth Hospital, Western Australia.
Acta Obstet Gynecol Scand Suppl. 1990;153:63-7. doi: 10.1111/j.1600-0412.1990.tb08034.x.
Urinary incontinence was observed in 19 patients after bladder neck elevation or vaginal repair operations. Characteristically, patients could not suppress their urge to micturate on getting up in the morning, and they wet before arrival at the toilet. Urodynamically, a high posterior cough transmission ratio was noted. A 1.5 cm longitudinal incision in the vagina, dissected free and resutured horizontally (I-plasty), immediately cured this particular condition, but ultimately failed in 1/3 cases. Most of these failed patients were subsequently cured by further adjustment of vaginal tension under local anaesthesia (Tuck procedure). These findings confirm the emphasis given by the Integral Theory of Female Urinary Incontinence as to maintain adequate elasticity in the zone of critical elasticity (ZCE) of the supralevator vagina. The ZCE acts as an elastic hinge, allowing (i.e. facilitates) the separate and opposite contractile forces of anterior pubococcygeus, and levator plate which are necessary to close off urethra and bladder neck respectively. Inadequate elasticity at the ZCE converts the ZCE's role from facilitation to opposition. The stronger levator muscle contraction counteracts the forward section of the weaker anterior part of pubococcygeus muscle, preventing bladder neck closure.