Experimental Study No. 2: A direct test for the role of the pubourethral ligament in anorectal closure
PETER PETROS (*) - MICHAEL SWASH (**)
(*) Royal Perth Hospital, University of Western Australia
(**) Dept of Neurology, The Royal London Hospital, London, UK
Abstract: Midurethral anchoring controlled solid feces loss during coughing in a patient with a history of stress fecal and urinary incontinence.
This experiment demonstrated the importance of an intact pubourethral ligament when both conditions occur simultaneously.
Key words: Stress fecal incontinence; 'Simulated operation'; Pubourethral ligament; Integral theory.
The series of video X-ray photographs (Study No. 1), appeared to support the Theory's prediction of a major role for the pubourethral ligaments in the control of fecal incontinence. A serendipitous presentation of a patient with a history of stress induced fecal incontinence at Royal Perth Hospital Outpatients Gynaecology Clinic allowed this part of the Theory to be tested directly.
A 54 year old patient, para 3, presented with a long history of leaking solid feces on coughing or straining. She discharged a bolus of feces on being asked to cough. This was replaced in her anus, and a sponge-holding forceps was gently pushed upwards onto the vaginal wall, on one side, at the level of the middle part of the urethra ('simulated operation'). Leakage of solid feces during coughing and straining was controlled immediately. On removing the forceps, leakage was noted again on straining. This procedure was repeated several times, and the same results reproduced on each occasion. Subsequently the patient had a midurethral sling operation, and reported total cure of this problem.
Robert Zacharin1 described how the pubourethral ligament
inserts into midurethra and the anterior portion of
m.pubococcygeus, (PCM, Fig. 1).
Both PCMs sweep backwards to form the levator plate (LP), Fig. 1; the levator plate 'LP' is attached to the posterior wall of rectum 2 by fascia which it tensions and stretches backwards. The levator plate has to be well-tensioned before the longitudinal muscle of the anus (LMA) can pull down its anterior border to effect anorectal closure around a firmly contracted puborectalis muscle (PRM) (see X-ray study, this issue). A lax pubourethral ligament (PUL), would not allow LP to contract sufficiently for LMA to rotate it around PRM for closure. A forceps applied to the site of the pubourethral ligament provides the firm anchoring point needed to restore the maximum contraction required for anorectal closure.
The observations confirm the participation of directional muscle forces acting against pubourethral and uterosacral ligaments during anorectal closure and also, defecation. Prospective surgical reinforcement of these ligaments will be required to test the hypothesis that ligamentous damage is a major cause of idiopathic FI. The results from such operations are described in Part 2.
- Zacharin RF. A suspensory mechanism of the female urethra. Journal of Anatomy 1963; 97: 423-427.
- Courtney H. Anatomy of the pelvic diaphragm and ano-rectal musculature as related to sphincter preservation in ano-rectal surgery. American Journal Surgery 1950; 79: 155-173.
Prof. Peter Petros,