Open reduction and internal fixation of condylar fractures via an extended bicoronal approach with a masseteric myotomy

Open reduction and internal fixation of condylar fractures via an extended bicoronal approach with a masseteric myotomy

British Journal of Plastic Surgery (1996), 49, 79-84 0 1996 The British Association of Plastic Surgeons Open reduction and internal fixation of condy...

2MB Sizes 16 Downloads 27 Views

British Journal of Plastic Surgery (1996), 49, 79-84 0 1996 The British Association of Plastic Surgeons

Open reduction and internal fixation of condylar fractures via an extended bicoronal approach with a masseteric myotomy D. J. Dunaway and J. A. Trott Department of Plastic and Reconstructive Surgery, Royal Adelaide Hospital, Adelaide, South Australia S UMMAR Y. Although condylar fractures of the mandible may he treated by closed reduction and appropriate physiotherapy, open reduction and internal fixation is indicated in specific circumstances. We report 25 cases of a previously unreported method of exposure of condylar fractures using an extended bicoronal approach combined with myotomy of the masseter muscle. Acceptable reduction and fixation was achieved in all cases with an early return to function. The incidence of complications was low, with three mild temporary facial palsies which had resolved by the sixth postoperative week and one haematoma beneath the bicoronal scalp flap. A cosmetically acceptable scar was produced in all cases. The excellent surgical exposure and protection of the facial nerve, combined with cosmetically acceptable scars, commend the use of this technique.

Management of condylar fractures of the mandible remains controversial, chiefly because of uncertainty over the natural history of conservatively managed fractures. A review of the literature reveals that the majority of patients treated by conservative means obtain satisfactory function. There is an ability for the condyle to remodel, particularly in children. Where fracture union was not anatomical, Lindahl’ noted that asymmetrical movement, clicking and tenderness of the temporomandibular joint (TMJ), although rare in children, were frequent sequelae of conservative management of condylar fractures in adults. In selected cases, open reduction and internal fixation allows for condylar fractures to be accurately reduced and rigidly fixed, resulting in an earlier return to normal function. Operations should only be considered in cases where the displaced fragments are large enough to be reduced and stabilised in three dimensions. An acceptable operative procedure should fulfil the following criteria:

ous submandibular incisions’ and a retromandibular incision.6 We present the use of an extended coronal scalp incision atid myotomy of the masseter muscle. Patients and methods

25 patients underwent open reduction and internal fixation of condylar fractures between June 1989 and October 1994. All patients were treated by the senior author. 17 were male and 8 were female and ranged in age from 5 to 58 years, with a median age of 25 years. There were 21 unilateral condylar fractures and 4 bilateral fractures. 8 patients had associated medial or antero-medial condylar dislocations (Table 1). Subcondylar fracture was the only fracture present in 9 cases. 14 patients had an associated parasymphyseal or symphyseal fracture of the mandible and 2 had contralateral angle fractures. 10 patients had an associated mid-facial or zygomatic fracture. The overall severity of facial fractures was assessed by the coding system described by Cooter and David.7 Facial fracture scores ranged between 2150 and 33150, with an average of 8.4. Patients were selected for operative treatment of their condylar fractures by criteria similar to those suggested by Zide and Kent8 in 1983. These indi-

1. There must be no operative morbidity from injury to nerves. 2. The fractures and dislocations must be reduced so that the muscles which act on the condyle regain normal tension and position. 3. Damage to the attachment of the lateral pterygoid muscle to the condylar head must be minimised. 4. Stabilisation must be maintainable until bony union occurs. 5. Restoration of normal function and occlusion should occur within 6-12 weeks.

Table 1

Distribution of fractures in patients studied No.

Unilateral fracture Bilateral fracture Unilaterial fracture dislocation Bilateral fracture with unilateral fracture dislocation

The central problem in designing an approach to the mandibular condyle is gaining adequate exposure whilst protecting the facial nerves from damage. The condyle may be approached via an intraoral incision2 or through various skin incisions, including those in the preauricular area,3 a postauricular incision,4 vari79

Associated

fractures

Symphyseul

Angle

Zygoma

Midface

14 3 7

9 3 2

1 0 1

4 0 1

I 1 1

1

0

0

1

1 -

80 cations were divided into absolute and relative categories. Absolute indications for operations were: 1. Fracture dislocations of the head into the middle cranial fossa or temporal fossa if associated with clinical disability. 2. Intra-articular foreign body. 3. Lateral extracapsular dislocation of the condyle. 4. Inability to open the mouth or bring the mandible into occlusion after 1 week of conservative management, with evidence of a bony block. 5. Compound injuries. The relative indications in this series differed from those suggested by Zide et al. and can be summarised as follows: 1. Children (less than 14 years old), medial dislocation of the joint and angulation of a condylar fracture of greater than 90 degrees. 2. Adults (greater than 14 years old), loss of vertical mandibular height through vertical displacement of fracture. Fracture dislocation of the temporomandibular joint with an angulation greater than 60 degrees. In this series, 2 patients fell into the first category, one aged 5 years and the other 13. Both had suffered unilateral low subcondylar fractures associated with anteromedial condylar dislocations. All information for this study was recorded on a standard pro-forma used by the Australian CranioFacial Unit to document the management of facial fractures admitted to the Unit. The minimum radiographic examination included an orthopantomogram (OPG), PA Mandible and reverse Townes view. 2D and 3D CT were used where there was multiple facial trauma or where these standard investigations failed to satisfactorily delineate the injury. Postoperatively, reduction was assessed clinically and radiographically. Clinical examination included a careful assessment of occlusion, maximal incisal opening and the presence of deviation of the mandible at maximal opening, together with an assessment of facial symmetry, facial nerve injury and any signs of temporomandibular joint dysfunction. Postoperative radiographs included an OPG, PA mandible and a reverse Townes view. The follow-up period ranged from 4 to 65 months, with a mean follow-up of 14 months. For the purposes of this study, postoperative clinical findings were recorded in the lst, 3rd and 6th week, at 4 months and again at a period of greater than 1 year.

Operative technique

A bicoronal scalp incision is made and extended inferiorly along the natural contours of the helix and tragus to the level of the earlobe (Fig. 1A). The temporal part of the incision is designed to be hidden by the fall of the hair. It is often unnecessary to extend the coronal incision fully on the contralateral

British Journal of Plastic Surgery side. The scalp is turned down in the subgaleal plane to a level l-2 cm above the supraorbital rim. From here the dissection continues subperiosteally to the orbital rim on the affected side (Fig. 1B). Lateral to the orbit at about the level of the frontozygomatic suture, the lamina externa of the deep temporal fascia9 is incised and dissection proceeds inferiorly through the fatty plane in this area to expose the zygomatic arch. Dissection at this level spares the frontal branches of the facial nerve. The masseter muscle is exposed to a distance of 2 cm below the zygomatic arch and the capsule of the temporomandibular joint is identified (Fig. lC, D). The parotid gland is separated from the cartilaginous external auditory meatus but no attempt is made to dissect formally the trunk of the facial nerve, which is left encased in soft tissue. Starting posteriorly, l-2 cm below the zygomatic arch the masseter muscle is divided, taking care to avoid damage to the neurovascular structures passing through the sigmoid notch (Fig. 1C). It is now possible to expose the condylar neck, sigmoid notch and upper mandibular ramus. The facial nerve has been reflected inferiorly with the flap, allowing direct vision of the fracture site with minimal traction on the soft tissue about the facial nerve. Reduction of the fracture or fracture dislocation is often aided by the insertion of a 13 mm screw into the proximal fragment to use as a handle, which may be grasped by strong artery forceps. Further assistance in reduction of the fracture may be gained by the use of a suitably notched instrument applied to the sigmoid notch to produce an inferiorly displacing force on the distal fragment. The wide exposure obtained by incising the posterior masseter muscle allows assessment of the fracture reduction and condylar relocation achieved against the pull of the lateral pterygoid muscle. Great care is taken to avoid surgical damage to the joint capsule and lateral pterygoid muscle. Once reduction has been achieved, a 4-hole titanium miniplate is contoured to fit the lateral aspect of the condylar neck and mandibular ramus. Four screws are inserted, two above the fracture and two below the fracture (Figs lE, F). The screw originally used for manipulation of the proximal fragment is then removed. The masseter muscle and the lamina externa of the deep temporal fascia are repaired with resorbable sutures. The scalp wound is closed in two layers and 6/O interrupted nylon sutures used to close the preauricular wound. Intermaxillary fixation (IMF) is unnecessary. However, minor occlusal discrepancies may require treatment with elastic traction applied through arch bars placed at the time of operation. In the case of an isolated condylar fracture, postoperative management is initially with a non-chew diet and gentle mobilisation. By the 6th postoperative week, mobilisation is usually complete and the patient may resume a normal diet. In children, the plates and screws are removed at around the 12th postoperative week via the same bicoronal approach in order to avoid interference with mandibular growth. Plates and screws are left in situ indefinitely in adults.

Bicoronal auuroach for condvlar fractures

E

\--

81

\“

Fig. 1 Figure l-(A) Marking of incision for the bicoronal flap. (B) Bicoronal flap reflected. (C, D) Exposure of the masseter muscle (M) and TMJ capsule (C), with deep temporal fascia (T) over temporalis muscle. Dotted line shows site of masseteric myotomy. (E, F) Reduced subcondylar facture fixed with a titanium miniplate and screws.

Results

25 patients underwent open reduction with plate and screw fixation of 29 condylar fractures. Bony union was obtained in each patient. Radiological assessment of fracture reduction revealed excellent reduction in 28 of these fractures (an example is shown in Figure 2). In the remaining fracture, the posterior border of the proximal fragment was noted to be fixed 3 mm posteriorly to the posterior border of the distal fragment. In this patient, who had also suffered a Le Fort I maxillary fracture, the occlusion was noted to be satisfactory and a rapid return to normal

function was achieved. 21 of the 25 patients achieved their pre-traumatic occlusion immediately postoperatively. 3 of the remaining patients developed a mild to moderate posterior premature contact of the ipsilateral side. These mild malocclusions resolved within 4 months without the need for further intervention. In the remaining patient, postoperative malocclusion was due to inadequate reduction of a comminuted contralateral parasymphyseal fracture which required further operative intervention. Adequate maximal interincisal opening was achieved by all patients, with a range of 37-50 mm and a mean opening of 43 mm. (Table 2). Immediate postoperative mobilisation

British Journal of Plastic Surgery

82 Table 2 Maximum mandibular opening (interincisal distance in mm)

Mean maximum interincisal distance (range in parenthesis)

1 week

3 weeks

6 weeks

4 months

>I

25 (16-30)

30 (23-40)

35 (25540)

41 (30-50)

43 (37-50)

Fig. 2 Figure 2-(A) Preoperative orthopantomogram (OPG), anterio-medial fracture dislocation of the right mandibular (B) Post OPG, showing reduction of fracture and plate Arch bars placed during surgery in case a minor occlusal ancy needed treatment.

showing condyle. fixation. discrep-

resulted in a mean interincisal distance of 2.5 cm at the end of the first postoperative week, with an increase to 3.5 cm by the 6th week. 5 patients developed a deviation of the mandible to the ipsilateral side on maximal opening. This deviation was mild in all cases, but failed to resolve in 3 patients. There were no cases of permanent facial nerve injuries; however, one mandibular branch and 2 mild frontalis branch palsies were noted, all of which had resolved by the 6th postoperative week. One patient suffered a haematoma under the bicoronal flap which needed reexploration on the night of surgery. The ultimate quality of preauricular and scalp scars at 1 year was judged to be satisfactory by clinician and patient in all cases reviewed. There were no cases of persisting temporomandibular joint dysfunction. Discussion

Closed reduction of condylar fractures has remained popular because good results are generally obtained and it avoids the possible disadvantages of open reduction, such as facial nerve damage, difficulty in manipulating cornminuted fragments and the production of a scar on the face. The larger reviews of closed reduction show that 6-35% of patients suffer short-term problems such as pain, limitation of open-

year

ing and deformity. 1o-12 The longest reported followup of condylar fractures by closed reduction is about 20 yearslo which, as well as demonstrating early dysfunction, showed an incidence of late arthritic changes in joints not in their appropriate anatomical position. Dahlstrom et a1.13, in their 15-year followup of conservatively treated condylar fractures, noted that moderate signs of dysfunction can be expected after condylar displacement in adults. The rationale for open reduction and internal fixation in selected cases is that it allows an earlier return to normal function’ without the need for IMF or elastic traction and the belief that accurate anatomical reduction will reduce the incidence of late arthritic changes. To date, there have been no studies with sufficient length of follow-up to enable assessment of late changes of the temporomandibular joint following operative management of condylar fractures. Comparison of early outcome between surgically and non-surgically treated groups is difficult, as most studies select patients with more severe injuries for treatment by open reduction and internal fixation. Takenoshita et a1.i4 compared functional recovery after surgical and non-surgical treatment of condylar fractures and found that early recovery of movement and opening was better in the conservatively treated group. However, patients for operative treatment were chosen on clinical grounds and both groups were placed in intermaxillary fixation for the first three postoperative weeks, thus negating the potential advantage of early mobilisation in the open reduction group. Konstantinovic and Dimitrijevic” demonstrated superior anatomical reduction of surgically reduced fractures in a non-randomised study but showed no clinical benefit over conservative management. Worsaae and ThornI conducted a randomised study of surgical versus non-surgical treatment of unilateral dislocated low subcondylar fractures and concluded that there was significantly less morbidity in the surgically treated group at a median follow-up period of 2 years. There are many factors influencing the decision to elect for open reduction of condylar fractures. Children and adults need to be considered separately. Lund17 and Lindahl and HollandeP showed remodelling of displaced condylar fractures occurring in childhood with associated compensatory growth. Remodelling was incomplete in patients nearing completion of growth and where the condylar head was dislocated from the glenoid fossa. Excessive compensatory growth causing deviation of the chin also occurred in some cases. Lund17 found no relationship between the degree of compensatory growth and the height of the fracture. Lindahllg demonstrated the presence of asymmetrical mandibular movements in conservatively treated children and adults and noted that, whilst these movements had generally resolved

Bicoronal approach for condylar fractures in 2 years in children, they tended to persist in adults. In a long-term follow-up of conservatively treated paediatric condylar fractures, Norholt et al.20 observed radiological abnormalities of ramus height and condylar morphology on the injured side but noted that these findings did not correlate with clinical or subjective assessments of dysfunction. It was also noted that long-term TMJ dvsfunction was less common in patients sustaining injuries at earlier ages. Many authors favour conservative management for the treatment of condylar fractures in childhood.‘3.20-24 However, we believe that open reduction and internal fixation is indicated in those cases where remodelling is likely to be incomplete and therefore choose operative management where there is medial dislocation of the joint and marked fracture angulation. It is our belief that early restoration of normal anatomical relationships and muscle vectors will encourage normal growth patterns. In adults, the indications suggested by Zide and Kent’ have found general acceptance in the recent literature.14x’5s23.25 With the growing acceptance of open reduction and internal fixation, the indications for open reduction are expanding. Sargent and Green25 suggested that open reduction should be considered for bilateral condylar fractures with persistent open bite, subcondylar fractures associated with vertically displaced ramus fractures, severely displaced condylar fractures and unstable fractures in patients who cannot tolerate intermaxillary fixation. These indications are in broad agreement with the criteria used to select operative management in this study. If open reduction and internal fixation is to be undertaken, accurate and rigid fixation of the fracture is necessary to gain good functional results. Condylar fractures have been classified into intracapsular, and high or low subcondylar fractures. Intracapsular fractures are not amenable to open reduction and internal fixation. For many surgeons, the distinction between high and low subcondylar fractures is of significance in deciding the surgical approach. Sargent and Green25 suggested that high fractures are best approached by a preauricular incision and low fractures by a retromandibular incision. Intraoral approaches such as that described by Lachner et al.2 are also popular for low subcondylar fractures. Accurate reduction and adequate fixation rely on good surgical exposure of the fracture and it is our experience that the extended bicoronal approach gives excellent access to almost all subcondylar fractures. screws Titanium alloy plates with unicortical ( AusSystem) have provided adequately rigid fixation in all cases. We believe that the consistent production of anatomical reduction shown in this study is primarily due to the excellent exposure provided by the bicoronal approach and myotomy of the masseter muscle. This allows direct rather than oblique visualisation of the temporomandibular joint and fracture site. The approach has been shown to be safe in that no serious complications were produced. Of the three mild facial nerve palsies in this study, all had resolved by the sixth post-operative week. Postoperative functional recovery compares favourably with other studies looking at operative and non-operative treatment

83

in the recent literature. However, long-term followup will be needed to determine the incidence of late temporomandibular joint dysfunction and arthritis in these patients with operatively treated fractures and fracture dislocations. Conclusion Most condylar fractures may be treated by closed reduction. However, there are a number of fracture patterns and dislocations in which open reduction and internal fixation of condylar fractures is considered to be beneficial. An acceptable operative procedure must give sufficient access to allow anatomical reduction and rigid fixation of the fracture and must avoid damage to the facial nerve and pericondylar structures, particularly the attachment of the lateral pterygoid muscle to the condylar head and articular disc. Any scars produced should be ultimately inconspicuous. We believe that the wide exposure afforded by the extended bicoronal approach and masseteric myotomy, combined with the reflection of the facial nerve away from the operation site and positioning of the skin incision in cosmetically advantageous areas, commend the use of this technique. References 1. Lindahl L. Condylar fractures of the mandible. I. Classification and relation to age. occlusion, and concomitant injuries of teeth and teeth-supporting structures, and fractures of the mandibular body. Int J Oral Surg 1977: 6: 1221. 2. Lachner J, Clanton JT, Waite PD. Open reduction and internal rigid fixation of subcondylar fractures via an intraoral ;;;zch. Oral Surg Oral Med Oral Path01 1991; 71: 3. Al-Kayat A, Bramley P. A modified pre-auricular approach to the temporomandibular joint and malar arch. Br J Oral Surg 1979; 17: 9lllO3. 4. Hoopes JE. Wolfort FG, Jabaley ME. Operative treatment of fractures of the mandibular condyle in children using the post-auricular approach. Plast Reconstr Surg 1970: 46: 357.-62. 5. Messer EJ. A simplified method for fixation of the fractured mandibular condyle. J Oral Surg 1972; 30: 44223. 6. Ellis E III, Dean J. Rigid fixation of condyle fractures. Oral Surg Oral Med OrallPathol 1993; 76: 6615. 7. Cooter RD. David DJ. Comnuter based codine of fractures in the craniofacial region. Br J Plast Surg 198u9; 42: 17-26. 8. Zide MF, Kent JN. Indications for open reduction of mandibular condyle fractures. J Oral Maxillofac Surg 1983: 41: 89 -98. 9. Lang J. Clinical Anatomy of the head, neurocranium, orbit and craniocervical regions. New York: Springer-Verlag. 1983: 104. 10. Chalmers J. Lyons Club. Fractures involving the mandibular condyle. A post-treatment survey of 120 cases. J Oral Surg 1947; 5: 45573. Il. Blevins C, Gores RJ. Fractures of the mandibular condyloid process: results of conservative treatment in 140 cases. J Oral Surg 1961; 19: 393-407. 12. Cook RM, MacFarlance WI. Subcondylar fractures of the mandible. A clinical and radiolographic review. Oral Surg Oral Med Oral Path01 1969; 27: 2977304. 13. Dahlstrom L, Kahnberg KE. Lindahl L. IS year follow-up of condylar fractures. Int J Oral Maxillofac Surg 1989: 18: 18-23. 14. Takenoshita Y, Ishibashi H, Oka M. Comparison of functional recovery after nonsurgical and surgical treatment of condylar fractures. J Oral Maxillofac Surg 1990: 48: 119ll5.

84 15. Konstantinovic VS, Dimitrijevic B. Surgical versus conservative treatment of unilateral condylar process fractures: clinical and radiographic evaluation of 80 patients. J Oral Maxillofac Surg 1992; 50: 349-52. 16. Worsaae N, Thorn JJ. Surgical versus nonsurgical treatment of unilateral dislocated low subcondylar fractures: a clinical study of 52 cases. J Oral Maxillofac Surg 1994; 52: 353-60. 17. Lund K. Mandibular growth and remodelling processes after condylar fracture. A longitudinal roentgencephalometric study. Acta Odont Stand 1974; 32: Suppl 64: 3-117. 18. Lindahl L, Hollander L. Condylar fractures of the mandible. II. A radiographic study of remodelling processes in the temporomandibular joint. Int J Oral Surg 1977; 6: 153-65. 19. Lindahl L. Condylar fractures of the mandible. III. Positional changes of the chin. Int J Oral Surg 1977; 6: 166-72. 20. Norholt SE, Krishnan V, Sindet-Pedersen S, Jensen IB. Pediatric condylar fractures: a long-term follow-up study of 55 patients. J Oral Maxillofac Surg 1993; 51: 1302-10. 21. Posnick JC, Wells M, Pron GE. Pediatric facial fractures: evolving patterns of treatment. J Oral Maxillofac Surg 1993; 51: 836644. 22. Feifel H, Albert-Deumlich J, Riediger D. Long-term followup of subcondylar fractures in children by electronic computer-assisted recording of condylar movements. Int J Oral Maxillofac Surg 1992; 21: 70-6.

British Journal of Plastic Surgery 23. Hayward JR, Scott RF. Fractures of the mandibular condyle. J Oral Maxillofac Surg 1993; 51: 57-61. 24. Kaban LB. Diagnosis and treatment of fractures of the facial4 bones in children 1943-1993. J Oral Maxillofac Surg 1993; 51: 122-9. 25. Sargent LA, Green JF, Jr. Plate and screw fixation of selected condylar fractures of the mandible. Ann Plast Surg 1992; 28: 235-41.

The Authors David J. Dunaway MB ChB, Registrar in Plastic Surgery James A. Trott MB BS, FRACS, Surgeon Royal Adelaide Australia.

Hospital,

North

BDS,

FDSRCS,

FRCS, Terrace,

FRCS,

Consultant Adelaide

Correspondence to Mr D.J. Dunaway FRCS, Senior Department of Plastic Surgery, Royal Victoria Newcastle Upon Tyne, NE1 4LP, UK. Paper received 6 February 1995. Accepted 9 August 1995, after revision.

Senior

Craniofacial 5000,

South

Registrar, Infirmary,