TREPHINING OF THE FRONTAL SINUSES. 29 



trephining through the external wall only, and consequently 

 in order to complete the drainage aside from that through 

 the superior maxillary sinus an artificial communication be- 

 tween the frontal sinus and nasal fossa may be made at ST, 

 Plate VII, by first making a second trephine opening op- 

 posite that point near the median line and then breaking 

 through the thin walls of the turbinated bone by means of 

 a probe or other suitable instrument and enlarging the open- 

 ing sufficiently with the probe pointed bistoury or with the 

 finger. In order to prevent aspiration of fluids, the animal 

 must be allowed to get up immediately or if under anaes- 

 thesia a trachea tube should be inserted sufficiently early to 

 avoid danger. Thread a long probe with a heavy silk suture 

 about 75 cm. long and inserting it through the trephine 

 opening into the nasal passage draw it out through the 

 nostril and removing the probe attach a strip of gauze 

 75 cm. long to one end of the suture, draw it out through 

 the nostril and tie the ends of the gauze together on the side 

 of the face to prevent dislodgement. Retain the gauze 

 in position for about forty-eight hours to insure the per- 

 manency of the opening through the turbinated bone. In 

 case of severe hemorrhage the cavity can be tamponed for 

 twenty-four hours with a long strip of gauze which may 

 be secured if necessary by suturing to the lips of the wound. 

 In practice the operation can be best carried out generally 

 with the animal in the standing position the operative area 

 being first anaesthetized by the use of cocaine or by inducing 

 artificial oedema. In the standing position we largely avoid 

 the danger of aspiration of fluids and the hemorrhage is 

 greatly lessened. 



