RADICAL OPERATION FOR FISTULA OF THE WITHERS 315 



ous degree, this, step may prudently be postponed for two 

 or three days or more, especially when it is evident that the 

 making of orifices through thick vascular muscles will cause 

 a too great loss of blood. It does not matter how deep the 

 sinuses are located, or what position they occupy, their 

 drainage by gravity is essential to rapid recovery. 



Various methods may be adopted in tracing tracts and 

 locating depths of sinuses. If an estimate can not be made 

 of the position by simply passing a probe or sound along 

 the tract, sometimes by moving it about impressions of its 

 end can be felt with the other hand pressing upon the sur- 

 face of the body. Sometimes the exact position can be lo- 

 cated by packing the tract and- sinus full of gauze with a 

 gauze packer until a bulging announces the exact location. 

 Injections of methylene blue solution two per cent into the 

 tract stains the course and often may thus facilitate tracing 

 by dissection. But by far the most certain and rapid method 

 of tracing tracts and establishing drainage is that of passing 

 a bendable seton needle into the bottom of the sinus and 

 .then thrusting its point through to the surface of the body 

 at one stroke. A tape is thus drawn through the trc ': to 

 serve as a guide to enlarge the opening to the desired di- 

 mensions. 



This seton method of constructing and maintaining 

 drainage is by far the most effectual if the tape is success- 

 fully carried to the very depths of the sinus and then directly 

 out to the surface. It provides a maximum of drain- 

 age with a minimum of injury to healthy, non-implicated 

 tissues. In the fistulae located at the highest point of the 

 withers the point of exit of one seton is just anterior and a 

 little below the anterior- angle of the scapula, and that of 

 the other between the posterior angle of the scapula and the 

 dorsal spines. Tapes so adjusted drain perfectly the space 

 between the cartilage of prolongation and the spinous pro- 

 cesses, if they are fearlessly passed deep enough to follow 

 the floor of the sinus. In fistulae located anteriorly with the 

 sinus resting upon the last cervical and first dorsal segments 

 the point of exit is the middle of the neck just in front of. the 

 shoulder. When necessary the opposite side is treated in the 

 same manner. Rubber drainage tubes, well perforated, may 

 be used instead of tape setons. These are drawn in with 

 the tape tied to one end. 



In more superficial fistulae incision through the skin and 

 muscles into the bottom of the sinuses may answer well 

 enough, but in deep specimens the incisions close before the 



