320 TREPHINING THE FACIAL SINUSES. 



indicated. Where putrefactive processes are actively going on, 

 3 per thousand permanganate of potash, or solutions of astringent 

 materials — such as alum 2 per cent., tannin 2 per cent. — may be 

 used. The openings are then closed with plugs, so as to guard the 

 mucous membrane against the direct influence of the air. Treat- 

 ment should be continued as long as any nasal discharge is present. 

 The wounds are afterwards encouraged to heal, only soft plugs being 

 used in the trephine openings. In about three or four weeks they 

 close completely, and after the lapse of two or three months scarcely 

 a trace of the operation can be observed. 



Where large tumours are to be removed from the frontal or 

 superior maxillary sinus a single opening may not be sufficient ; 

 a second is bored in the neighbourhood of the first, and the inter- 

 vening bone removed with the assistance of the chisel (Fig. 311) and 

 the hammer. Moller has frequently had occasion to trephine the 

 nasal roof in this way in order to remove tumours or necrotic portions 

 of the turbinated bones. A saw similar to a key-hole saw is useful 

 here in order to enlarge the trephine opening. 



To facilitate drainage Siedamgrotzky suggested a modified method 

 of operation. He operated about £ to § of an inch in front of a 

 horizontal line drawn through the two inner angles of the eyes, and 

 1^ to 1| inches from the middle line of the face. After washing out 

 the sinus cavity he effected a communication between it and that 

 of the nose by thrusting a director downwards and inwards at the 

 deepest spot, breaking through the thin plate of bone and the mucous 

 membrane covering it, and enlarging the opening so made by excising 

 with a tenotome an oval fragment f inch long and | inch wide. To 

 avoid injuring the septum nasi the knife is only introduced a short 

 distance and the operation performed at the deepest spot. The 

 resulting bleeding ceases in a few minutes ; if not, the cavity may 

 be plugged. To prevent inspiration of blood the horse is at once 

 allowed to rise ; for a similar reason anaesthetics are withheld. 



Although diseases of the frontal sinuses occur in cattle, they are 

 less common than in horses. In sheep, on the other hand, the 

 presence of oestrus ovis may necessitate the opening of the frontal 

 sinuses. This is usually done in the middle line, in order that both 

 sinuses can be opened simultaneously, and washed out by injections. 

 The frontal sinus, as in other ruminants, is connected with the horn- 

 core, and may be opened by sawing through the horns ; but this 

 operation is not only more painful, but is also accompanied by 

 greater loss of blood, which in animals already weakened may be 

 attended with undesirable consequences. 



