glottis, new corks with smaller grooves being
substituted as laryngeal breathing becomes easier. Corking the cannula
is an excellent orthopedic treatment in certain cases where muscle
atrophy and partial inflammatory fixation of the cricoarytenoid joints
are etiological factors in the stenosis. The added pull of the
posterior cricoarytenoid muscles during the slight effort at
inspiration restores their tone and increases the mobility of all the
attached structures. By no other method can panic and spasmodic
stenosis be so efficiently cured.

[FIG. 111.--Illustration of corks used to occlude the cannula in
training patients to breathe through the mouth again, before
decannulation. The corks allow air leakage, the amount of which is
regulated by the use of different shapes. A smaller and still smaller
air leak is permitted until finally an ungrooved cork is tolerated. A
central hole is sometimes used instead of a slot. A, one-third cork;
B, half cork; C, three-quarter cork; D, whole cork.]

Following the subsidence of an acute laryngeal stenosis, it is my rule
to decannulate after the patient has been able to breathe through the
larynx with the cannula tightly corked for 3 days and nights. This
rule does not apply to chronic laryngeal stenosis, for while the lumen
under ordinary conditions might be ample, a slight degree of
inflammation might render it dangerously small. In these cases, many
weeks are sometimes required to determine when decannulation is safe.
A test period of a few months is advisable in most cases of chronic
laryngeal stenosis. Recurrent contractions after closure of the wound
are best treated by endoscopic bouginage. The corks are best made of
pure rubber cord, cut and ground to shape, and grooved, if desired, on
a small emery wheel (Fig. 112). The ordinary rubber corks and those
made of cork-bark should not be used because of their friability, and
the possible aspiration of a fragment into the bronchus, where rubber
particles form very irritant foreign bodies.

[FIG. 112.--This illustration shows the method of making safe corks
for tracheotomic cannulae by grinding pure rubber cord to shape on an
emery wheel. After grinding the taper, if a partial cork is desired, a
groove is ground on the angle of the wheel. If a half-cork is desired
half of the cork is ground away on the side of the wheel. Reliable
corks made in this way are now obtainable from Messers Charles J.
Pilling and Son.]

BIBLIOG