Book 7
4
4 Again, for fistulae which penetrate so deeply that a medicated bougie cannot be passed down to the ends, or those which are tortuous or multiple, surgery has the advantage over medicine; and there is less trouble if the fistula runs horizontally under the skin, than when it tends directly inwards. Therefore if it lies horizontally under the skin, a probe should be introduced and cut down upon. When there are bends, these are followed up in the same way with the probe and knife; so also when they present multiple branchings. When the end of the fistula is reached, all the callus should be cut out, then pins are inserted through the skin margin, and agglutinating medicaments spread over all. But if it runs straight inwards, after its chief direction has been explored by means of the probe, that cavity ought to be excised, then a pin is to be inserted through the skin opening, and agglutinating medicaments applied as above; or if there is more corrupt ulceration, which is at time the case when there is disease of bone, after the bone has been treated, suppuratives are put on.
