FRACTURE OF THE MIDLINE OF THE MANDIBLE ASSOCIATED WITH COMPLETE UNILATERAL DISLOCATION OF THE JAW By IAN H. HESLOV, M.B., B.S., B.D.S., F.D.S.R.C.S.(Eng.) Maxillo-facial and Oral Surgery Department, Withington Hospital, Manchester FRACTURE of the condylar neck, with or without displacement or dislocation of the condylar head from the glenoid fossa, is a relatively common type of jaw injury. MacLennan (1952) reviewed 18o such cases, of which twenty-seven were fractur~ dislocations. Rowe and Killey (1955) record 227 fractures of the condyle in a series of 638 mandibular fractures. Dislocation or subluxation of one or both temporo-mandibular joints is by no means rare, and is often seen in patients in whom the ligaments of these joints have become stretched and lax as a result of long-standing overclosure of the bite. This condition may arise more acutely as a result of trauma from a carelessly used Mason's gag, the jaw being forcibly opened beyond its normal range so that the condyle or condyles pass on to the anterior surface of the articular eminence. Following such trauma the condition may recur spontaneously. However, the combination of fracture of the body or of the midline of the mandible, with dislocation of one condyle from the glenoid fossa, in the absence of an associated fracture of the condylar neck or the adjacent ascending ramus, appears to be extremely uncommon. No record has been found in the literature of such a case and it does not fit into the usual classification of fractures and fracture dislocations of the mandible. It is for these reasons that the following cases are reported, though additional features were observed in Case I, which are also of interest. CASE REPORTS Case x.--this boy of 17 years of age was in collision with a motor car whilst riding a bicycle. He was unconscious for a few minutes following the accident, but was fully conscious and co-operative on admission to hospital half-an-hour later, though he remembered little of the accident. Condition on Admission.--His general condition was quite good, the blood-pressure being lo8/7o mm. Hg and the pulse regular and of good volume. He was only slightly shocked and there was no systemic evidence of extensive blood loss. Examination showed that injury was confined to the region of the face and jaws. Clinical Findings in the Injured Area.--There was a deep laceration running through the full thickness of the lower lip just to the left of the midline. This cut ran downwards and laterally across the chin and into the neck: it gaped widely and in the floor the mandible could be seen as bare bone denuded of periosteum. The upper incisor teeth and their alveolus were shattered, as were the lower incisors, two of which floated loosely in the mouth tethered by only a strand of muco-periosteum on the lingual aspect. Examination of the general contour of the mandible showed a compound comminuted fracture in the midline, with a marked downwards displacement of the right main fragment. 12 9
13o BRITISH JOURNAL OF PLASTIC SURGERY The disturbance in the occlusal levels on the two sides of the mouth was such that the presence of a second fracture on the right side of the mandible was suspected. The left posterior teeth were almost in occlusion, whilst the separation of the right upper and lower posterior teeth in the first pre-molar region was nearly 5 cm. However, examination revealed that the cause of the marked depression of the right fragment was in fact a dislocation of the right temporo-mandibular joint, without further fracture being present. The right condylar head could be palpated about 2 cm. anterior to the normal " open" position. There were no other fractures of the facial skeleton and no other injuries to the face, head, or neck. Radiographic Examination.--ThJs confirmed the midline fracture of FIG. i the mandible and showed the Case I. Lateral radiograph of jaws, showing the three presence of a ~separate triangular main mandibular fragments and the dislocation of the right temporo-mandibular joint, bone fragment in the midline. The dislocation of the right temporomandibular joint without fracture of the condylar neck was also demonstrated (Fig. I). The sketch (Fig. 2) shows more clearly the outlines of the three main fragments. Treatment. -- Early operation was necessary because of the nature of the injury, and intra-oral examination showed I J adequate firm teeth for interdental eyelet wiring as a means of jaw immobilisation. His general condition was good when re-examined four hours after admission, ss S /s" and grouping and cross-matching had been carried out soon after he was first seen in case blood transfusion was needed. It was therefore decided to operate as soon as possible. Operation.--Under endotracheal anaes-,," t '~s ~ I thesia the wounds were examined more... ~ s ~ I ".....~ I." I thoroughly than had been possible in the ",...e ~ i conscious patient (Fig. 3)- They were then cleaned, and interdental eyelet wires were FIG. 2 applied to the posterior teeth in all quadrants Case I. Tracing of radiograph shown in of the mouth. Intermaxillary tie wires were Fig. I. Right main fragment represented loosely placed (Fig. 4)- by broken line, left main fragment by continuous line and loose triangular fragment by All fragments of loose bone and teeth dotted line. were removed together with several teeth which had been much loosened in the areas adjacent to the shattered teeth. Altogether 2I ) I2 432I i I23 were lost. The alveolus in the 2III2 area was trimmed and the mucoperiosteum sutured.
FRACTURE OF THE MIDLINE OF THE MANDIBLE 131 The main mandibular fracture was then examined and found to be the shape of an inverted Y, with the arms of the Y enclosing the loose triangular bone fragment. Fig. 3.--Case I. Fig. 4.--Case I. FIG. 3 FIG. 4 The injury closely resembled a " gunshot wound." The marked downward displacement of the right side of the mandible may be seen. Wound cleaned. Eyelet wires and intermaxillary fixation loosely applied. Fig. 5.--Case I. Fig. 6.--Case I. FIG. 5 FIG. 6 Interosseous lower border wires placed. Mandibular fragments reduced. Interosseous wires tightened and intermaxillary fixation secured. This fragment included the genial tubercles and was considered to be viable, though it was denuded of periosteum on its anterior surface. Lower border wiring was carried out between the triangular fragment and the major fragment on each side, a simple direct loop being used on the right side and a direct and a figure-of-eight loop on the left (Fig. 5). The dislocation was reduced, and it was then possible to reduce and maintain the fragments in perfect position by means of the lower border interosseous wires (Fig. 6).
13 2 BRITISH JOURNAL OF PLASTIC SURGERY Immobilisation was completed by twisting up the intermaxillary wires, which brought the teeth into occlusion. The soft tissues were restored to their position and the wounds closed in layers. One pint of whole blood was given during the course of the operation. FIG. 7 Case I. Post-operative postero-anterior and lateral oblique radiographs showing satisfactory position of fragments. FIG. 8 Case I. Nineteenth post-operative day. Post-operative Progress.--Post-operative radiographs showed satisfactory position of the fragments (Fig. 7). The patient progressed satisfactorily and was discharged on the nineteenth post-operative day (Fig. 8). The intermaxillary fixation was removed and the fracture found to be firmly united in good position six weeks after operation.
FRACTURE OF THE MIDLINE OF THE MANDIBLE ~33 Jaw movements were encouraged and a good range of movement was obtained with only slight limitation of the left lateral excursion. (Note.--Fourteen days after the accident the patient sat the General Certificate of Education at the advanced level and passed in all subjects.) Case 2.--This patient was also knocked off a bicycle by a motor car. He was admitted to a nearby hospital and given emergency treatment before transfer to Wythenshawe Hospital the following day. FIG. 9 Case 2. Condition on admission. The gagged open jaw, bilateral circumorbital ecchymosis, and cerebrospinal rhinorrheea are to be seen. Condition on Admission.--Apart from abrasions over the right knee and clavicle, thc injuries were confined to the region of the jaws, face, and head. His general condition was not very good, due to fracture of the frontal bone and an associated head injury. Clinical Findings in the Injured Area.--Extraorally.--Marked swelling of the face, the left eye being closed. Lacerations of the forehead, which had been sutured. Right and left circumorbiml ecchymosis. Left subconjunctival hmmorrhage. Evidence of recent epistaxis (Fig. 9). Intra-orally. 765432111234567 76 432I! Iz345 78 were present. The mouth was gagged open on the posterior teeth.
i34 BRITISH JOURNAL OF PLASTIC SURGERY There was an obvious fracture of the middle third of the facial skeleton, the maxilla being mobile, and there was in addition an alveolar fracture in the /678 area with downwards displacement of that portion of the upper jaw. FIG. IO Case 2. Intraoral view, showing the very marked step deformity at the site of the single mandibular fracture. The midline of the mandible was fractured, the left side being displaced downwards I "5 cm. below the right in the incisor region (Fig. IO). Clinically this was the only fracture of the mandible. Radiographic Examination.--This confirmed the fractures of the frontal bone, maxilla, and the midline of the mandible and showed no other fractures (Fig. II). Treatment.--Metal cap splints were constructed for all segments of the fractured jaws, excluding/678. These were cemented to the teeth and a plaster headcap was applied as a means of fixation of the fractured maxilla. The headcap was relieved in the area of the lacerations of the forehead and the fractured frontal bone. The maxilla was then gently reduced and fixed to the headcap attachments by means of rods secured to Kingsley bows on the upper splint, and intermaxillary elastic traction was applied to reduce the FIG. I I Case 2. Postero-anterior radiograph of mandible showing the midline fracture and the displacement of the fragments. mandibular fracture. Some improvement was obtained in the position of the mandibular fragments, but the reduction was not complete, and on the eleventh day after admission the patient was considered fit for a general ana:sthetic. Operation.--Under endotracheal anms- thesia all fixation was removed and manual reduction of the mandibular fracture was attempted. It then became apparent that the left temporo-mandibularjoint was dislocated,
FRACTURE OF THE MIDLINE or THE MANDIBLE I3~ and this was reduced without much difficulty. The mandibular fracture came into good position following this procedure, and after some improvement of the position of the maxilla by manipulation, intermaxillary and craniomaxillary fixation was replaced. For the latter only an anterior bar was used, from the headcap to the upper splint, the Kingsley bows being discarded. Post-operative Progress.--The patient made satisfactory progress, though union was slow in the mandibular fracture. This was due in part to the unavoidable delay in obtaining complete reduction and immobilisation, and partly to the site of the fracture in the midline of the mandible, a region which is normally slow to heal unless the fracture is oblique with a large area of bone contact. He was discharged home four weeks after operation, at which time the maxilla was firm. All fixation was removed at the sixteenth post-operative week when the mandibular fracture was firm. This case was treated by Mr A. W. Moule, F.D.S.R.C.S., and Mr H. D. Penney, F.D.S.R.C.S., and is the only one in their experience which has presented with this phenomenon of separate and distinct fracture and dislocation. DISCUSSION As already stated, one of the interesting features of both cases is the unusual combination of midline fracture of the mandible and unilateral dislocation, without further fracture of the condylar neck or of the ascending ramus. The general appearance of the face in Case I was of interest (Fig. 3), in that it resembled a gunshot wound much more than a " civilian " type of injury. With the speed of motor vehicles and the number of road accidents both on the increase, it may be that this " burst open " appearance of the face, with a comminuted fracture in the depths of the wound, resulting from contact with part of a fast-moving vehicle, will become more common amongst civilian maxillo-facial injuries. In describing the clinical features to be found in fractures of the mandible, Rowe and Killey (1955) state : "When only one fracture is obvious intraorally, but the degree of displacement is greater than usual for that type of fracture, it will be prudent to suspect another fracture on the same side... Fractures of the canine region and the condyle, or the symphysis and the angle, may be found to coexist." The cases described above must surely be the exception which proves this rule, for there was but one fracture of the mandible in each case and the degree of downward displacement of the right fragment in the midline in Case I was about 7 cm. The downward displacement of the left fragment in Case 2 was 1.5 cm. in the midline of the jaw. I am grateful to Mr A. W. Moule, F.D.S.R.C.S., for supplying me with Case 2, and for permission to publish both cases ; and I should like to thank the Photographic Department, Wythenshawe Hospital, for the illustrations. REFERENCES MACLENNAN, W. D, (1952). Brit. J. plast. Surg., 5, 122. RowE, N. L., and KILLEY, H. C. (1955). " Fractures of the Facial Skeleton," p. 3o. Edinburgh : E, & S. Livingstone.