Chapter 19

OPERATIONS ON THE JAWS.

1. EXCISION OF THE UPPER JAW.--With regard to the morbid conditions for which this operation is undertaken, it may be sufficient here to observe, that in no case can the operation be called justifiable in which the disease extends beyond the upper jaw-bone and the corresponding palate-bone, for unless the morbid growth be entirely removed, recurrence is inevitable, and no advantage is gained by the operation. It is undertaken for the removal of tumours of the antrum and of the alveolar margins, in all which cases the section for its removal must be made through healthy bone, and wide of the disease, so as to insure that the whole is removed. There are other cases in which the whole or part of the upper jaw has been removed for the purpose of giving access to disease behind, for example, to naso-pharyngeal polypi with extensive attachments.

In describing the operation for the excision of the entire upper jaw, we have to consider--(1.) what incisions through the soft parts will expose the tumour best, and with least deformity; (2.) what bony processes require to be divided, and where. Very various incisions have been recommended by various authors; some describing three, in various directions, forming flaps of different sizes, while others, again, are satisfied with a very small division of the upper lip into the nose, or even attempt removal of the bone without any incision through the skin at all. These discrepancies depend in great measure on different views of what constitutes excision of the upper jaw, the more complicated ones contemplating removal of the whole bone anatomically so called, including the floor of the orbit, while the less complicated ones are suitable for cases in which a much less extensive removal is required.

To remove the whole bone, an incision (Fig. XXVII. A) of the skin must extend from the angle of the mouth upwards and outwards in a slightly curved direction with its convexity downwards, as far on the malar bone as half an inch outside of the outer angle of the eye. The flaps must then be raised in both directions, the inner one specially dissected off the bones, so as to expose thoroughly the nasal cavity. It is of great importance thoroughly to display the floor of the orbit, so that the attachment of the orbital fascia may be accurately cut through, the inferior oblique muscle divided at its origin, and the eye and the fat of the orbit cautiously raised from its floor.

Three processes of bone then require attention and division.

(1.) The articulation with the opposite bone in the hard palate. To divide this, one incisor tooth at least must be drawn, the soft palate divided by a knife to prevent laceration, and the thick alveolar portion sawn through in a longitudinal direction from before backwards.

(2.) The articulation with the malar bone at the upper angle of the incision through the skin. This must be notched with a small saw in a direction corresponding to the articulation, and then wrenched asunder by a pair of strong bone-pliers.

(3.) The nasal process of the upper jaw must now be divided by the pliers, one limb of which is cautiously inserted into the orbit, the other into the nose. If the disease extends high up in this process, it may be necessary partially to separate the corresponding nasal bone, and thus reach the suture between the nasal process and the frontal bone. The pliers must now be inserted into the groove already made by the saw on the hard palate, and the separation continued to the full extent backwards. A comparatively slight force exerted on the tumour either by the hand, or (when the tumour is small) by a pair of strong claw forceps, will suffice to break down the posterior attachments of the bone and remove it entire. The necessary laceration of the soft parts behind is so far an advantage, as it lessens the risk of hæmorrhage from the posterior palatine vessels.

The hæmorrhage from this operation was at one time much dreaded, but is rarely excessive; very few vessels require ligature, except those divided in the early stages in making the skin flaps; the hollow left should be stuffed with lint, which may be soaked in the perchloride of iron should there be any oozing.

The incisions recommended for this operation have been very various, and a knowledge of some of them may occasionally be useful, on account of specialities in the shape and size of the tumour. Liston "entered the bistoury over the external angular process of the frontal bone, and carried it down through the cheek to the corner of the mouth. Then the knife is to be pushed through the integument to the nasal process of the maxilla, the cartilage of the ala is detached from the bone, and lip cut through in the mesial line; the flap thus formed is to be dissected up and the bones divided."[108] Dieffenbach made an incision through the upper lip and along the back or prominent part of the nose, up towards the inner canthus, from whence he carried the knife along the lower eyelid, at a right angle to the first incision as far as the malar bone.

In cases where the tumour is of moderate size, Sir W. Fergusson found[109] it sufficient to divide the upper lip by a single incision exactly in the middle line, this incision to be continued into one or both nostrils, if required. The ala of the nose is so easily raised, and the tip so moveable as to give great facilities to the operator for clearing the bone even to the floor of the orbit.

In cases where the tumour is larger, or the bones more extensively affected, Sir W. Fergusson preferred an extension of the foregoing incision (Fig. XXVII. B) upwards along the edge of the nose almost to the angle of the eye, and thence at a right angle along the lower eyelid, as far as may be necessary, even to the zygoma. The advantages claimed for such procedures are that the deformity is less and the vessels are divided at their terminal extremities.

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.

Disarticulation of the entire bone has been very rarely performed.[111] If necessary, it can be performed without any incision into the mouth, by one semilunar sweep from one articulation to the other, passing along the lower margin of each side of the body, and just below the symphysis of the chin.

_Disarticulation of the Ramus without opening into the cavity of the Mouth._--That this operation is possible, though it may not be often required, is shown by the following case by Mr. Syme. It was a tumour of the ramus, extending only as far forwards as the wisdom-tooth:--

"An incision was made from the zygomatic arch down along the posterior margin of the ramus, slightly curved with its convexity towards the ear, to a little way beyond the base of the jaw. The parotid gland and masseter muscle being dissected off the jaw, it was divided by cutting-pliers immediately behind the wisdom-tooth, after being notched with a saw. The ramus was then seized by a strong pair of tooth-forceps, and notwithstanding strong posterior attachments, was drawn outwards, its muscular connections divided and turned out entire. There was thus no wound of the mucous membrane of the mouth, the masseter and pterygoid muscles were not completely divided, and the facial artery was intact."[112]

Fergusson[113] holds that even the very largest tumours of the lower jaw may be successfully removed without opening into the orifice of the mouth at all by division of the lips. A large lunated incision below the lower margin of the bone, with its ends extending upwards to within half an inch of the lips, will give free access, and yet avoid both hæmorrhage and deformity, as the labial artery and vein are not cut, and there is no trouble in readjusting the lips. Some tumours of lower jaw can be removed without any wound of skin.

FOOTNOTES:

[107] Diagram of operations on the jaws:--A, incision for removal of the whole upper jaw; B, incision for removal of alveolar portion and antrum; C, incision for removing the larger half of lower jaw; the opposite side is the one supposed to be operated on, and the incision is crossing the symphysis and turning up at a right angle.

[108] _Operative Surgery_, p. 265.

[109] _Lancet_, July 1, 1865.

[110] Temporary compression of the facial can be easily managed, in cases where it is of much importance to avoid loss of blood, by passing a needle from the outside through the skin above the vessel, then under the vessel, and out again through the skin below. A figure-of-eight suture can then be thrown round both ends of the needle, and the artery thus thoroughly compressed.

[111] Syme, _Contributions to the Path. and Practice of Surgery_, p. 21; Carnochan of New York, _Cases in Surgery_.

[112] _Contributions to the Path. and Prac. of Surgery_, pp. 23, 24.

[113] _Lancet_, July 1, 1865.