Artificial vela are always somewhat complicated, and that success will attend their use cannot be assured. They consist of a vulcanite or gold palate plate fastened to some of the teeth, and of a moveable flap attached to it by a hinge and spring of suitable strength ([Figs. 72 and 73]), or simply of a rubber flap sewn to the posterior margin of the plate ([Fig. 74]). These vela either rest above the palatal segments, or their sides can be grooved to allow the palatal segments to fit into them. It is very difficult to obtain an artificial velum sufficiently strong to retain its position, and yet light enough to allow of its being easily moved by the displaced and probably weakened muscles.
Figs. 72 and 73.—Figures of artificial velum as seen from below and above, consisting of a metal palate plate with a velum hinged to it, and supported above by a spring of suitable strength. (Coles.)
Fig. 74.—Another form of artificial velum. (Coles.)
In 1864 Dr. N. W. Kingsley, of America, suggested for this purpose the use of soft india rubber of such delicacy as to resemble the normal velum as nearly as possible. The rubber was arranged in two layers, one of which rested above and behind the cleft, and the other overlapped for about half an inch all the margins of the cleft seen from the front. This amount of overlapping was found sufficient to prevent the apparatus from becoming displaced during muscular contraction, and at the same time by its means allowed the palate muscles to effect closure of the posterior nares.
Mr. Baker, in the ‘Boston Medical and Surgical Journal,’[99] describes a velum consisting of rubber distended with water, which was fixed with a hinge to the back of the palatal plate, and under the control of the muscles by being inserted above them on either side. A stop prevents it falling too low, and the posterior extremity is almost semicircular to allow of perfect apposition with the pharyngeal wall, which is drawn forward by the superior constrictor. He claims to have met with much success.
Wolff and Schiltsky have devised a similar apparatus, but use air instead of water for distending the hollow rubber velum.
The main arguments that have been educed in favour of the use of artificial substitutes for the palate rest upon the fact that until recently the results of operative interference in severe cases of fissured palate were often very unsatisfactory; in most, if not all, an aperture was left anteriorly, which caused the speech of the patient to remain indistinct. But with the greater success which has followed increased experience and practice, this cause can be eliminated; and, moreover, secondary operations for the attainment of this object can always be undertaken with every prospect of success. Another objection raised to operation is that no immediate improvement takes place in the power of clear articulation; and although this is perfectly true, the patient is in the same condition in this respect as when first provided with an obturator, and will require the same educational process for the improvement of speech. Again, the mental effect on patients operated on is much more satisfactory than that following the application of artificial assistance; whilst the presence of a foreign body in the mouth is a source of continual danger and irritation; for there is always the possibility of the obturator slipping out of position and becoming impacted in the pharynx or œsophagus. Irritation of the sides of the cleft not uncommonly results from their use, and may end in ulceration and even necrosis. When obturators and vela are removed from the mouth, a spongy granulating surface is often seen, bleeding on the slightest touch, and giving rise to a peculiar fœtor of the breath. Under these circumstances a temporary discontinuance of the apparatus becomes necessary, a most undesirable and unpleasant contingency.