450 



TRACHEOTOMY. 



and in the event of stenosis supervening, the operation may be 

 repeated at a lower point. The various complicated tracheotomes 

 and trocars proposed by Brogniez, Marty, Gowing, Murray, Spooner, 

 Thompson, Hayne and others, and intended to facilitate the 

 operation, are seldom used. Two operation methods 

 may be noticed : (1) Puncture, and (2) Incision of the 

 trachea. 



(1) Puncture of the trachea was recommended by 

 Pilger, Gowing, Hayne, and others. Hayne's method 

 met with most approval, and consisted in passing a 

 trocar, provided with a cannula having lateral openings, 

 transversely through the trachea (Fig. 350). This 

 operation required some skill and care, particularly 

 in a well-developed neck, in order to avoid injuring 

 the jugular and carotid ; while even the large cannula, 

 used for heavy working-horses, did not admit sufficient 

 air. The origin of this procedure, which does not 

 possess even the advantage of being rapidly carried 

 out, could only have been fear of using the knife. 

 Thompson's tracheotome was designed to simplify 

 operation, though its value is not great. It consists 

 of special forceps (see Figures 351 to 355), with jaws 

 bent at right angles to the limbs and externally ground 

 to a sharp cutting edge. When closed, the head of the 

 instrument is readily thrust through the skin and into 

 the trachea ; the jaws are then opened and the cannula 

 slid into position between them. The figures very 

 clearly show the instrument and the mode of using it. 



(2) Incision into the trachea is most generally 

 practised. The trachea may be opened by vertical 



|t section of several rings, or by excision of a portion 



JMif|(| of two or three rings. Vertical section or splitting, 

 HaP"** although it increases the difficulty in introducing the 

 W cannula, is sometimes preferred where the tube is to be 



worn only temporarily, is less apt to cause deformity 

 and stenosis, and hence is generally commended in 

 acute diseases like strangles for foals and race-horses, 

 in which even slight dyspnoea is dreaded. The ex- 

 cision of a portion of the trachea facilitates the introduction and 

 removal of the cannula for cleaning, and is specially desirable in all 

 cases of chronic dyspnoea where a tube must be permanently worn 

 by the horse. Experience does not justify the belief that stenosis 



Fig. 350. 



Hayne's 



tracheal 



trocar. 



