A Manual of the Operations of Surgery / For the Use of Senior Students, House Surgeons, and Junior Practitioners

by Joseph Bell

2. Excision of the Lower Jaw.—Removal of portions, greater or smaller, of the lower jaw, for tumours, simple or malignant, are now operations of very frequent occurrence, while in some few cases the whole bone has been removed at both its articulations.

The operative procedures vary much, according to the amount of bone requiring removal, and also the position of the portion to be excised.

(1.) Of a portion only of one side of the body of the bone.—This is perhaps the simplest form of operation, and is frequently required for tumours, specially for epulis.

Incision.—If the parts are tolerably lax and the tumour small, a single incision just at the lower edge of the bone, of a length rather greater than the piece of bone to be removed, will suffice; this will divide the facial artery, which must be tied or compressed,[110] while the surgeon, dissecting on the tumour, separates the flaps in front, cutting upwards into the mouth, and then detaches the mylohyoid below, and clears the bone freely from mucous membrane. He then, with a narrow saw, notches the bone beyond the tumour at each side, and, introducing strong bone-pliers into the notches, is enabled to separate the required portion. The wound is then stitched up, and a very rapid cure generally results with very little deformity, as the cicatrix is in shadow. If from the size of the tumour more room is needed, it can easily be got by an additional incision from the angle of the mouth joining the former.

To prevent deformity, which is apt to result from the centre of the chin crossing the middle line, it is often a wise precaution to have a silver plate prepared fitting the molar teeth of both jaws on the sound side, and thus acting as a splint. Such a precaution may be required in any operation in which the lower jaw is sawn through.

N.B.—There are certain cases in which the epulis is small and confined to the alveolar margin, in which an attempt may be made to retain the base of the jaw entire, and remove the tumour without any incision of the skin. The mucous membrane on both sides being carefully dissected from the affected part, the bone may be sawn as before, but only through the alveolar portion, the groves of the saw converging as they penetrate, then by a pair of strong curved bone-pliers, the affected alveolar portion is to be scooped out without injuring the base. This proceeding, which has been practised by Syme, Fergusson, Pollock, the author in many cases, and others, leaves no deformity, but, it must be owned, is much more liable to the risk of recurrence of the disease, and for this reason is strongly condemned by Gross.

Note.—In this, as in all other operations on the jaws, the very first thing to be done is to draw the teeth at the spots at which the saw is to be applied.

(2.) Excision of a portion involving the Symphysis.—Free access is of importance. The best incision is probably one which (Fig. xxvii. C) commences at the angle of the mouth opposite the healthy portion of jaw, extends down to the place at which the saw is to be applied and then along the base of the jaw past the middle line to the other point of section. The flap is to be thrown up and the bone cleared. The next point to be noticed is, that when, in clearing the bone behind, the muscles attached to the symphysis are divided, the tongue loses its support, and unless watched may tend to fall backwards, embarrassing respiration and even perhaps choking the patient. The tongue, being confided to a special assistant, must be drawn well forwards. Various plans have been devised for keeping it in position, as stitching it to the point of the patient's nose; putting a ligature into its apex, and fastening it to the cheek by a piece of strapping, and transfixing its roots with a harelip needle, used to stitch up a central incision in the chin. The tendency to retraction very soon ceases, new attachments are formed by the muscles, and after the first five or six days there is very little risk of the tongue giving rise to any untoward consequences by its displacement.

(3.) Disarticulation of one, or both Joints.—When the portion of bone implicated involves disarticulation for its complete removal, the difficulty of the operation is much increased. The remarkably strong attachments of the joint, especially the relation of the temporal muscle to the coronoid process, and the close proximity of large arteries and nerves, especially the internal maxillary artery and the lingual nerve, render this disarticulation very difficult.

The chief points to be attended to seem to be (1.) that the incision through the skin should extend quite up to the level of the articulation; (2.) that the bone should be sawn through at the other side of the tumour, and freely cleared from all its attachments, before any attempt be made at disarticulation, for by means of the tumour great leverage can be attained, so as to put the muscles on the stretch, and allow them to be safely divided; (3.) that the articulation should always be entered from the front, not from behind, and the inner side of the condyle should be very carefully cleaned, the surgeon cutting on the bone so as to avoid, if possible, the internal maxillary artery; (4.) free and early division of the attachment of the temporal muscle to the coronoid process.