CHAPTER VIII. 



LITHOTOMY. 



DEFINITIONS.^Lithotomy is the incision of the blad- 

 der for the abstraction of calculi therein. In animals, the in- 

 cision is usually made into the urethra, where it becomes su- 

 perficial above the arch of the ischium, hence the correct 

 designation should be "urethrotomy," or, in order to better 

 explain the objects of the operation, "urethrolithotomy." 

 Lithotripsy, lithuresis, or lithotrity refer to crushing of calculi 

 by means of the lithotrite — a crushing forceps specially de- 

 vised for the purpose. Litholapaxy refers to the special ope- 

 ration of pulverizing calculi with the lithotrite and then evac- 

 uating the fragments by irrigation or suction. 



INDICATIONS.— Vesical calculi occur in all of the do- 

 mestic mammals. They are, however, most common in the 

 ox. and in the dog. In the equine species they are noted for 

 their relative infrequency. 



The operation for their removal is indicated as soon as 

 they become incompatible with the health of the urinary or- 

 . gans by obstructing the flow of urine or by provoking inflam- 

 mation of the tissues they press upon. They may sojourn 

 for years without exciting any suspicion of their existence, 

 but may at any time flow into the urethra and at once cause 

 total obstruction, or they may gradually provoke changes in 

 the walls of the bladder that are finally announced by a more 

 or less pronounced distress in urination. 



Although the bladder is the usual seat of their develop- 

 ment, calculi may be found forming at any part of the urinary 

 channel from the pelvis of the kidney to the meatus urinarius. 

 Hence they may be renal, ureteral, vesical or cystic, or ure- 

 thral, either by reason of having developed in these several 

 organs or by having changed positions, from a higher level 

 in the urinary tract. Thus a renal calculus may become ure- 

 teral, vesical or urethral by being carried downward with the 

 current of urine. 



The operation of removing calculi from the urinary tract 

 does not modify the disease (lithuria) which causes their for- 

 mation and is therefore not a curative procedure. It only 

 rids the urinary tract of a harmful element and leaves the dis- 

 ease unchecked against recurrence. In dogs and in oxen the 



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