Fistula in Ano

This condition occurs more frequently than any other of the abnormalities of this region, Mr. Allingham finding 1208 out of his table of 4000 consecutive cases of diseases of the rectum and anus. He found also that fistulæ followed rectal abscess in 151 out of 196 cases, the abscesses which healed kindly and gave no further trouble being only 45 in number. A fistula in ano is a linear ulceration with a patulous orifice which discharges pus: it may or may not communicate with the bowel, and it may have more than one external opening. The great majority of fistulæ in this region are caused by abscess, either arising in the submucous areolar tissue of the bowel, or in the subcutaneous connective tissue in the immediate neighborhood of the anus, or in the ischio-rectal fossa, or in an ulcerated state of the mucous membrane of the rectum: in other cases it is congenital, or it may result from the presence of foreign bodies or worms in the bowel, or from puncture of the rectum by pins, scales of shell, fragments of bone, or other sharp substances swallowed with the food. Abscesses leading to fistulæ have followed kicks, blows, or wounds of the anal region: in short, anything which induces an abscess here may result in a fistula, and as in the former more cases occur in males than females, and more during middle age than at any other period, the same is true as to the latter. Fistula is quite common among the phthisical as a result of malnutrition and septicæmia, aided by the constant succussion of the perineum produced by efforts at coughing. Of the 4000 cases previously referred to, 1208 were cases of fistula; "of these, 172 presented more or less marked symptoms of lung trouble, hæmoptysis, cough, or impaired resonance in some portion of the chest."

A fistula may be complete or incomplete. To be complete, it must have two openings (it may have more)—one in the anus or rectum, and one upon the surface. There are two forms of the incomplete or blind fistula—one in which there exists an internal but no external opening, and the other in which there is an external but no internal opening. In complete fistula there may be more than one external opening, and this is in the majority of cases not far from the anus, but it may open in the perineum or upon any part of the gluteal region. When the openings are multiple they usually converge to form a common tract or sinus. The external opening presents nothing to the untutored eye to lead to the suspicion of grave internal trouble: frequently the vent is so minute and valvular or shielded by a thin pellicle as to be entirely overlooked; in other cases a little teat formed of superabundant granulations guards the entrance: there may or may not be discoloration, elevation, or depression of the surrounding integument, and erythema resulting from the irritating nature of the discharge. Inflamed and suppurating follicles in the integument about the anus are not to be mistaken for the orifices of fistulous tracts.

The internal opening in anal fistula is situated between the sphincter muscles, sometimes just within the anus, but oftener about half an inch above; in rectal fistula the internal opening or openings may be at any point above the internal sphincter. These sinuses may be very tortuous, with pockets, blind passages, or diverticulæ, and are known as horseshoe fistulæ when they commence at one side of the bowel and ulcerate around it to a point opposite before making an opening.

Of the two varieties of incomplete fistulæ, by far the least frequent is that where no internal opening exists, but where there are one or more external orifices: these do not invariably even run toward the bowel, but may extend off through the tissues in any direction. In the other variety, where there exists no external evidence of disease, considerable damage may be done before its recognition. Fistula may coexist with hemorrhoids, stricture, ulcer, or malignant growth: it may be a very trivial affair, with the internal but a fraction of an inch from the external opening, or it may be long, deep, and tortuous, with sinuses running in all directions through the buttock.

Usually, fistulæ become worse when not operated upon, but there are cases which have healed without surgical interference—others in which this condition has gone on for many years without getting any worse or without the discharge increasing in amount. The fluid discharged from a chronic fistula loses after a time much of its purulent character and becomes serous and watery; but fresh abscess and inflammation is apt to take place in these cases from feculent matter lodging in the sinus. Those which burrow most readily are the internal fistulæ with large openings, into which the feces are pushed, with the sinus running toward the anus, because of their funnel-shape.

The presence of fistula may be suspected if there are in the anal region abscesses which have not completely healed, or which, having apparently done so, break out from time to time and discharge pus; or from the existence of a circumscribed hardness or swelling unaccompanied by an opening which varies in size and is at times painful; or if there exist any ulcerated moist openings. To make a positive diagnosis the tract must be explored by a probe: enter the oiled, blunt-pointed probe gently into the external opening and let it find its way along without force, bending the probe if necessary, until it has traversed the sinus as far as it will go; then pass the finger into the rectum and feel about for an internal opening or for the point of the probe. If the finger be introduced first, the relations of the parts are interfered with and the internal opening, should one exist, might not readily be found. Sometimes the bottom of the tract does not correspond in situation to the internal opening, but extends beyond it. In those cases where no external opening exists, the rectal speculum, aided by judicious pressure, will discover an issue of pus from a sinus upon the mucous membrane of the rectum.

In order to illustrate the amount of damage which a small foreign body may cause when lodged in the rectum, Wetherill relates the following case, which occurred in his practice at the Pennsylvania Hospital for the Insane: The patient was a middle-aged man, intelligent, and an employé of the hospital. "Upon examination of the anal region I found a small, tender, firm swelling, which did not fluctuate, about an inch to the left of the anus: this had been forming for about a week, and there was no history of painful defecation, of exposure to damp and cold, nor of a blow or injury of the part. Without waiting for the development of fluctuation, I made a free and deep incision into the ischio-rectal space, and a large quantity of very fetid pus escaped: upon introducing a large probe I found that it passed up into the fossa to a depth of four and a quarter inches and turned but slightly toward the bowel. Remembering the experience of Allingham, that when the pus in these cases was very offensive there existed an opening in the bowel, I questioned the patient again as to pain in the bowel or painful defecation, which was answered in the negative. No communication could be found with the finger in the bowel and a probe in the wound, and poultices were applied, liquid diet ordered, and the man kept in bed. The cavity was loosely filled with absorbent cotton and the entire wound (apparently) healed slowly, but kindly, and in about ten days after operation the patient left the house to all appearance sound. About a week after the patient returned with the report that he felt uneasy throbbing in the part, and that there was a very slight discharge. Upon inspection I found in the surface-line of the cicatrix a pinhole opening which yielded upon pressure a drop or two of pus; upon entering a very fine probe it passed into a narrow sinus to a depth of three and a quarter inches, but no communication could be made with it with the finger in the bowel. Upon withdrawing the probe it grated over something which felt like dead bone, about two inches from the surface. I enlarged the opening, introduced a pair of fine dressing-forceps, and withdrew a piece of the rib of a chicken about half an inch in length and sharpened at one extremity to a fine point. Upon making inquiry I found that he had not eaten any chicken since the development of the abscess. He then suddenly remembered that while he was at stool a few days prior to the formation of the abscess he experienced a sudden pang of very acute pain in the rectum, which, however, soon passed off. This was no doubt the moment when the piece of chicken-bone pierced the rectum."