Tro′car.
（
Surgical.) (Fr.
Troiscarre, threefaced.) An instrument consisting of a perforator or stylet and a cannula.
After the puncture is made the stylet is withdrawn, and the cannula remains and affords a means of evacuating from the cavity.
Used in case of dropsy, hydrocele, etc.
Tapping for the dropsy was practiced by the ancients.
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Paracentesis trocars. |
Fig. 6664 shows forms of trocars for puncturing the eye in cases of dropsy of that organ.
The instrument (Fig 6665) invented by
Dr. Dieulafoy of
Paris is designed to remove fluids from cavities by means of capillary tubes and a suction-pump, so as not to leave an open wound nor admit air to the cavity.
It consists of a glass cylinder
a about 7 inches in hight and 2 in diameter, partly covered with a silver-plated casing, and having a tightly fitting piston which is raised or lowered by turning the handle
b. Near the bottom of the cylinder are the induction and eduction openings
d c, fitted with rubber tubes.
The capillary tubes or trocars are six in number, and of different sizes; one is shown attached to the induction-tube
d, and five below the instrument.
In addition to these there should be two or three small blunt cannulas with trocars and a detachable handle, so that when the trocar is withdrawn the cannula may be attached to the instrument.
In using the instrument, the cocks
c d are closed and the handle
b turned, producing a nearly perfect vacuum in the cylinder: the piston is held in raised position by a spring
e. The trocar is introduced with a rotary motion into the part from which the fluid is to be withdrawn; on opening the cock
d it flows into the cylinder, which is emptied when full by closing
d, opening
c, pulling out the spring
e, and lowering the piston; when this is done, both cocks are again closed, and the operation repeated.
The cylinder is provided with a scale graduated to grammes, for showing the amount of contained fluid, and a glass tube is inserted near the outer end of the induction-tube, through which the fluid while passing may be inspected.
The instrument is useful for removing fluids from the pleural and cranial cavities and the knee joint; for withdrawing pus from abscesses; gas and the fluid contents of the intestines; and it has been employed for puncturing the bladder above the pubes in cases of retention of urine.
Local anaesthetics may be applied to the part under treatment.
