Introduction The Kees classification is based upon the quantitative and qualitative amount of tissue loss and on the involvement of the anatomic stool continence mechanism in the female with consequences for the operation technique and prognosis. The fistula, which does not involve the anatomic stool continence mechanism without a rectum stricture and without a circumferential defect is a Kees Ia fistula. Also within this Kees Ia class, the variety is enormous.
Mechanism of action Pressure necrosis of the soft tissues in between the fetal skull and the maternal sacrum bone; so real anatomic tissue loss from minimal to extensive.
Characteristics Almost 100% combined with vesicovaginal fistula in Kees Ia fistulas there is always anatomic tissue loss of the rectum, pre rectal fascia, and posterior vagina wall with possible tissue loss of the posterior cervix. There may be major tissue loss with also trauma to the sacrospinous ligament, (ischio) coccygeus muscles, and piriformis muscles. The majority are located at the vault near or at the posterior cervix; with a fluid transition of the proximal Kees Ia into Kees Ib and into Kees Ic stool fistulas. The rest is located anywhere between the vault/cervix and the internal rectum sphincter (stool closing mechanism) with a fluid transition of distal Kees Ia into Kees IIa fistulas. Normally the fistulas are in the midline though they can be situated very laterally as well. If the fistulas are near or fixed to the posterior cervix, and if the cervix retracted into the abdomen or fixed towards one of the ischium spines, visualization and instrumentation will be complicated. Since the stool continence mechanism is not involved successful repair will ensure full stool/flatus continence. Small Kees Ia fistulas may heal spontaneously if no infection/no outflow obstruction as noticed during follow up in patients coming early for postpartum urine leakage and also passing flatus and/or stools per vaginam at first visit; and healed with full stool/flatus continence when seen later; so far, over 800 patients with spontaneous healing. The very proximal Kees Ia fistulas may be a surprising finding at examination at operation beginning or during operation for a vesicovaginal fistula (flatus; compression of distal rectum by speculum) since several patients say they have no complaints (maybe only when diarrhea) and some do deny its existence even upon explicit asking. nb the Kees Ia fistulas are almost 100% combined with a vesicovaginal fistula = vvf; isolated fistulas are rare.
Reconstruction Since the majority are deep inside the vagina the repair poses a challenge to the fistula surgeon since access, visualization, and instrumentation are complicated. Normally the rectum is closed transversely in line with the natural tissue forces and common sense. Infrequently the rectum is closed longitudinally in line with common sense. Seldomly an oblique fistula is closed obliquely. Purse string suturing was not really effective. In principle the rectum is closed by a double inverting layer; the first interrupted for strength and the second continuously for flatus proof closure. The sutures are thru the pre rectal fascia/muscularis resulting as well in rectum mucosa adaptation upon tying the sutures. Primary suturing is performed in some 20% with good results. Chance of healing is good; with excellent full continence of the closed/healed fistulas.
Discussion The deeper (parts of) the fistula inside the vagina the poorer the access and the more complicated the instrumentation, especially if combined with a retracted/moving cervix and fixation of the fistula onto the sacrum; the same for fistulas not in the midline. Try to bring the fistula towards the outside and if not in the midline towards the midline. Though the (proximal) fistulas may be complicated to repair the prognosis as to closure and continence is excellent. Actually, for all Kees Ia fistulas there is a fluid transition from proximal Kees Ia into Kees Ib and into Kees Ic fistulas and a fluid transition from distal Kees Ia into Kees IIa fistulas. Personal experience of the author with 1,417 consecutive patients right from the beginning the high tendency to spontaneous healing was noted whilst several had no symptoms despite a fistula so that only 501 patients needed surgery. Spontaneous healing in 837 (60%) 570 operations in 501 (35%) few/no symptoms in 79 (6%) patients not bothered the baseline data for the 501 patients as operated will be presented.
Author: Kees Waaldijk, MD, PhD, Babbar Ruga Fistula Hospital, Katsina, Nigeria