The operation for this deformity may be best undertaken about the fourth to sixth week of the infant's life (see Cleft Palate), according to Berry and Legg. It should be done earlier when associated with cleft palate than when the alveolus shows no deformity, but when suction is rendered impossible it may be necessary to operate on hare lip within the first ten days after birth. When cleft palate complicates the de formity, the lip should be first operated on. The child should be nour ished by careful spoon feeding, so as to be placed in the most favourable condition of health to withstand the strain of the operation and the subsequent restraint necessary to secure success.
The arms of the infant may he comfortably secured to its sides after chloroform anwsthesia by winding a towel round the thorax as the patient lies on the operating table with the head raised on a firm pillow or sand-bag.
The lip must be thoroughly separated from its bony attachments by cutting and gently tearing through the reflected mucous membrane in the neighbourhood of the cleft and beyond it well up into the nostril and cheek before any attempt is made at paring the edges of the cleft. After the soft parts are found to glide freely over the alveoli and the margins can be brought together without undue tension a fine, sharp scalpel is used to pare off and completely detach the edge of one side of the cleft, starting at its apex, till the red margin of the lip is reached, when the incision is prolonged clean through the blunt angle and for a short distance along the free margin of the lip by turning the cutting edge of the blade outwards. The remaining edge of the cleft is similarly pared till the lower angle of the cleft is reached. when the knife is again turned outwards to continue the incision along the red margin of the lip without detaching the dissected paring, which is then stitched to the opposite blunt angle so as to fill in the notch which would otherwise be left in the free margin of the lip. This A-shaped incision, when the parts are brought together in a mild degree of hare-lip deformity, becomes a diamond, and when sutured in its vertical axis leaves a straight line.
The margins of the wound arc sutured with two fine horsehair or silkworm-gut stitches passed deeply, but not made to include the mucous membrane, the intervening portions of the wound being stitched with horsehair sutures passed superficially. Lane inserts his deep sutures from the mucous surface, but does not include the skin in them. This plan permits these stitches to remain in situ for several days, whilst the deep sutures applied from the cutaneous surface must be removed after a or 3 days in order to avoid permanent marking. The horsehair ones may be left for a week or io days before removal. A small pad of gauze is applied over the lip and covered with Iodised Collodion. This latter is kept in position by a firm band of rubber plaster applied after the cheeks are pressed together in order to avoid traction on the margins of the wound when the child cries. The plaster should he renewed at intervals during the first 2 or 3 weeks after the removal of the sutures to prevent stretching of the cicatrix. The mouth should be kept aseptic by the use of Glycerin of Borax, and the child fed by a spoon for the first few days.
The operation of simple double hare lip is carried out on the same lines, and if there be no bone displacement both clefts can be dealt with at the same time.
Should there be much projection of the premaxillary process forwards, this a few days before the operation may be pressed forcibly backwards by forceps or by the thumb to the extent of causing its detachment from the bony septum, which is preferable to the plan of cutting out a V-shaped piece of the latter at the operation, whereby the blood-supply to the premaxillary bone may be destroyed. The prolabium should be pared and the skin left on its central part, the flaps being utilised in closing the cleft and forming a columna.