The screw handle is now rotated evenly and slowly, discharging the mass to be injected, which will soon be evidenced by the rise of the skin over the depression to be corrected.
Only sufficient of the mass must be injected to fairly correct, never to overcorrect, the defect.
Experience alone will assure the surgeon when this point has been attained, since he cannot immediately judge the necessary amount injected, as it will appear as a round or irregular lump under the skin, until it has been molded or worked out into shape.
Owing to the pressure exerted upon the contents of the syringe, which will continue to emerge from the needle for a time, the needle is left in place for a few seconds before withdrawal, so that the needle canal through the skin will not become filled with the semisolid mixture.
Such blocking up of the opening causes a cystic development or enlargement about the opening in the skin by this backing up or exuding, ofttimes crowding itself in between the layers of the skin and necessitating later removal with the knife. If not this fault it tends to keep the wound open unnecessarily after the operation, preventing healing and permitting the escape of a certain amount of the injected mass, if a mixture of low melting point has been utilized.
The needle, having been allowed to remain as advised, is now withdrawn. The tip of one finger is placed over the opening in the skin and held there gently, but firmly, while the mass is molded into the shape required or desired with the fingers of the right hand.
If it now appears that the injection is insufficient the needle may again be introduced through the same opening and more is injected, remembering, however, that if the correction is quite normal no more should be added for several days, or until the injected mass has become organized, which should take place in about three weeks.
If it is found that the skin over the defect is inflexible and bound down, it will be found advisable to sever or dissect subcutaneously the adhesions that bind it down with the use of a fine tenotome or a spear-headed paracentesis knife.