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Endoscopic mandibular condyle fracture repair
Atlas Oral Maxillofacial Surg Clin N Am 11 (2003) 169–178
Endoscopic mandibular condyle fracture repair Mark Martin, MD, DMD, Chen Lee, MD, FRCSC* Division of Plastic Surgery, Department of Surgery, McGill University Health Center, McGill University, Montreal, Quebec, 43G 1A4 Canada
The whole history of open reduction and internal fixation (ORIF) of bone fractures can be traced to the twentieth century. The historical evolution of operative treatment of facial fractures has evolved through several phases during this period. Early in the century, closed treatment of facial fractures was pervasive. The development of antibiotics led to increased interest in approaching these fractures surgically. The apogee of this philosophy in the era before rigid internal fixation was the suspension technique championed by Milton Adams, which dominated postWorld War II treatment of these injuries. The basic principle was to suspend fractured segments to the next highest stable landmark in the facial skeleton. These techniques could not control the vertical dimension of the fractured viscerocranium and led to short and retruded post-treatment facies. The development and popularization of rigid internal plating systems by such pioneers as Luhr revolutionized the approach to fractures of the midface and extracondylar mandible. The ability to maintain predictably the accuracy of reductions obtained at surgery opened the door to the extended open reduction techniques developed by such forward-thinking surgeons as Manson and Gruss. Anatomic restitution of the premorbid skeletal anatomy became possible, reproducible, and predictable. The extensive exposures used to achieve these skeletal results have occasionally come at some cost to the soft tissue envelope. The next stage in the advancement of treatment of facial fractures is already under way and revolves around the quest to duplicate the excellence of the skeletal results achieved by extended open reduction and fixation techniques, while minimizing the morbidity suffered by the soft tissue matrix surrounding this framework. The evolution of treatment of subcondylar fractures has paralleled somewhat that of other facial fractures, but it is also distinct in some regards. There has been much satisfaction expressed by many surgeons with the results of closed treatment of subcondylar fractures. Proponents cite simplicity, noninvasiveness, lack of facial scarring, and avoidance of facial nerve damage as benefits of closed over open treatment. Those championing open reduction and internal fixation of these fractures have focused on the benefits of immediate function, improved restoration of facial symmetry and projection, and improved jaw motion resulting from anatomic restoration. Certainly, accurate anatomical reduction of fractures is an accepted standard throughout the body and remainder of the facial skeleton. The clinical impressions of many surgeons in the past has been that the results of closed treatment of subcondylar fractures are generally good; however, well-designed and long-term studies addressing this issue are only now beginning to appear. These studies are starting to demonstrate tangible benefits to accurate reduction and fixation of these fractures. Even so, for any intervention the risks must be weighed against the benefits, and the modest benefits achieved by open techniques have not resulted in the widespread use of these methods which were accepted so rapidly in other facial fracture sites. The main reason for hesitation for most surgeons has centered on the morbidities of the open approach. The two major drawbacks are the inevitable facial scar and the risk of facial nerve damage. Many patients will find the scar objectionable, and abstract discussions of jaw motion abnormalities and late temporomandibular dysfunction will not be convincing to many
* Corresponding author. E-mail address: [email protected] (C. Lee). 1061-3315/03/$ - see front matter Ó 2003 Elsevier Science (USA). All rights reserved. PII: S 1 0 6 1 - 3 3 1 5 ( 0 2 ) 0 0 0 2 5 - 2
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M. Martin, C. Lee / Atlas Oral Maxillofacial Surg Clin N Am 11 (2003) 169–178
individuals. Many incisions to approach the condyle have been championed as the most aesthetic, yet none is without drawbacks, and all will result in particularly apparent scars in the young and/or dark-skinned patient. Furthermore, even a low percentage of facial nerve injuries are unacceptable to many surgeons and patients alike when weighed against the relative benefits. As clinicians have sought to achieve the benefits of ORIF while minimizing the morbidities associated with the open approach, endoscopic assistance has emerged as an exciting alternative. Endoscopic technology, having been developed and refined by gynecologists and general surgeons, has been a late addition to the treatment of maxillofacial injuries. Though naturally occurring optical cavities in the abdomen and chest lent themselves to the application of endoscopic technology, much anatomic study and surgical innovation was necessary to tap the advantages of this modality for use in the head and neck. The benefits of this effort are particularly evident in the treatment of subcondylar fractures of the mandible. By achieving anatomic reduction and rigid fixation, immediate function is possible; and occlusion, facial symmetry, and jaw motion are normalized. This is achieved while minimizing the morbidities associated with traditional incisional approaches. This article describes the operative technique used since the first description of endoscopic assisted open reduction and internal fixation (EAORIF) of subcondylar fractures.
Anatomy and classification The anatomy of the condylar region is well known to surgeons of the maxillofacial region. The dangers of trans-cutaneous approaches to the condyle are equally well known and are responsible for much of the hesitation many experienced surgeons have in addressing these injuries surgically. All transcutaneous approaches place the facial nerve at risk of iatrogenic transection. The facial nerve has been the subject of a tremendous amount of clinical-anatomic study during the past century. Attempts to group branching patterns into predictable groups abound in the surgical literature. A study of these thorough investigations leads the surgeon to the inevitable conclusion that variability in location of the individual branches is the rule, and that caution is the only reliable guide when traversing the plane of the facial nerve. Nerve stimulators can add some degree of safety in terms of avoiding transactions of major branches. Even so, it is apparent that simply identifying and dissecting out individual branches of the facial nerve may result in paresis of the facial musculature in a sizable minority of cases, as well as occasional permanent nerve dysfunction. Although temporary paresis complicating transcutaneous approaches is often minimized as a source of morbidity by those reporting case series, it is a complication resulting in much anxiety in surgeons and patients alike. Many complex classification systems for fractures of the condylar region have been proposed in the literature over the years. Although these classifications may have value in conducting research studies to separate prognostic factors that may one day guide treatment decisions, none have yet been validated by scientific study and the authors therefore find them unnecessarily cumbersome for clinical use. We use a simple system of classification that is commonly used in the literature and has clinical relevance. We classify fractures as condylar head (intracapsular), condylar neck, and subcondylar (Fig. 1). Condylar head fractures are not treatable by the endoscopic-assisted approach because of their intracapsular nature and lack of bone stock for mini-plate fixation. Fortunately, these high fractures often have excellent maintenance of posterior mandibular height; their consequences instead relate to possible development of late osteoarthritic changes. Condylar neck fractures lie between the intracapsular head and a tangent drawn through the nadir of the sigmoid notch. These fractures may be treatable by the endoscopic approach, depending on the amount of solid bone available for plate application. Subcondylar fractures are most commonly encountered and are usually treatable by EAORIF. We also subclassify fractures as having medial or lateral over-ride. In medial over-ride fractures, the proximal segment has scissored medial to the distal ramal segment; in lateral over-ride fractures, the proximal fragment will present overlapping the distal fragment on its lateral aspect (Fig. 2). The treatment implications of this classification are discussed below. We agree with most other clinicians who refer to separation of the fracture ends as displacement, and to dislodgement of the condylar head out of its position in the mandibular fossa as dislocation.
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Fig. 1. A simplified condylar fracture classification can be used to determine the feasibility of management by endoscopic-assisted methods of surgical repair. Condylar head fractures are not treatable by the endoscopic-assisted approach because of their intercapsular nature and lack of bone stock for mini-plate fixation. Fortunately, these high fractures often have excellent maintenance of posterior mandibular height. Consequences instead relate to possible development of late osteo-arthritic changes. Condylar neck fractures lie between the intracapsular head and a tangent drawn through the nadir of the sigmoid notch. These fractures are technically challenging to repair, as the size of the optical cavity for endoscopic repair is very limited. Most fractures present as subcondylar fractures extending below the nadir of the sigmoid notch.
Indications and contraindications Lists of indications and contraindications for open treatment abound in the literature. Many of these lists are mostly unhelpful to the clinician faced with a typical fracture of the condyle as they concentrate on situations that occur only very rarely, such as intracranial displacement. Our indications for approaching condylar fractures by EAORIF relate to the functional and aesthetic consequences of the fracture. Loss of posterior mandibular height on one side results
Fig. 2. (A, B) Subcondylar fractures can be further subclassifed as having medial or lateral over-ride. (C,D) Medial override fractures, where the proximal segment has scissored medial to the distal ramal segment, are extremely difficult to access and repair as the proximal condylar pole is ‘‘hidden’’ by the telescoped ascending ramus. Most adult fractures present with lateral over-ride at the ramal fracture interface. As the proximal fragment will present overlapping the distal fragment on its lateral aspect, the proximal condylar pole is more accessible to endoscopic manipulation and repair.
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in an asymmetry of the cranio-mandibular articulation. The cranio-mandibular joint is unique in the body by being a ginglymodiarthrodial joint, and in particular its bilateral nature. Many individuals are capable of an impressive degree of neuromuscular adaptation after subcondylar malunions, and they will learn to force themselves into maximal intercuspal position (MIP). This has been taken by many clinicians to equate to an acceptable result, but we would submit that when there is a loss of posterior mandibular height, a spectrum of predictable sequelae result. People find themselves in MIP for a very small portion of the day; instead, their teeth are most often separated in function or in an unconstrained position at the vertical dimension of rest (VDR), with several millimeters between their teeth. When at VDR, the functional matrix seeks to position the condyle in the mandibular fossa, and thus the anatomic asymmetry of the mandible becomes manifest at rest as the chin point deviates toward the side with the malunion. Likewise, in functional movements the deranged cranio-mandibular articulation is even more apparent as deviation of the chin point to the mal-united side worsens during attempts at maximal opening, as translational movements are often disturbed by the altered joint mechanics. Also visible clinically in these injuries is a loss of chin projection in the sagittal plane, resulting from a clockwise rotation of the mandible from a loss of posterior mandibular height. This is most profound in the bilateral case which more often overwhelms the patient’s ability to adapt by neuromuscular means and results in an anterior open bite in a higher percentage of cases treated by closed means. Though aware of the shortcomings of closed treatment, we also recognize that some fractures are not amenable to EAORIF. Fractures of the growing condylar region have been demonstrated to possess an impressive ability to remodel, and we therefore treat these injuries closed. Undisplaced fractures have been demonstrated to have good results following closed treatment, and we do not treat these injuries with EAORIF. Because our technique is dependent on accurate anatomic reduction of fracture lines, and also relies on some degree of interfragmentary friction to stabilize the reduction during fixation, severe comminution is considered a contraindication to using this technique. Our general indications to offer EAORIF to patients are displaced and/or dislocated fractures of the extracapsular condyle region, demonstrating some combination of malocclusion, loss of chin projection, and asymmetry at rest and/or in function, which do not display severe comminution, in adults without medical contraindications for surgery.
Diagnosis and imaging Patients presenting with signs and symptoms of craniofacial trauma to the emergency room often undergo a series of plane radiographs. It is our belief that plain radiographs, although often supplying sufficient detail to diagnose craniofacial fractures, do not provide sufficient detail to allow thorough treatment planning of these injuries. We feel this holds true for condylar fractures being considered for EAORIF as well. Therefore, if a patient presents with physical signs and symptoms suggestive of a condylar fracture, we proceed directly to fine-cut CT. These scans are acquired at 1.5 mm intervals in the axial plane, which allows for sufficient detail in the reformatted coronal images. Three-dimensional reformatted images require no extra radiation exposure to the patient and can be easily and routinely generated by most modern workstations, and they provide an easy-to-interpret overview of the fracture relations that may be helpful in planning the operation. With some experience in EAORIF of condylar fractures, surgeons soon develop the ability to select by inspection of CT scans those fractures with enough proximal bone stock, and without too much comminution, to be successfully treated by this method. When viewing the images, it is also important to note the presence of medial over-ride, which portends a more difficult reduction and the possible necessity for additional operative maneuvers, as discussed below.
Equipment Originally in the development of EAORIF of condylar fractures, equipment had to be adapted from that already in use for other purposes. Now, instrument sets specifically designed
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for this method are commercially available (Synthes Maxillofacial, West Chester, PA, USA). Here, we describe the equipment currently used by the authors, which is similar to equipment available in most major medical centers. The endoscope we use is a 4-mm diameter, 30 -angle scope (Karl Storz, Tuttlingten, Germany). A 4-mm endoscope-mounted retractor is useful in maintaining the optical cavity (Karl Storz). The endoscopic image is displayed on a video system (Olympus America, Inc., Lake Success, NY) consisting of a three-chip camera (Olympus XLS), camera converter (Olympus 3C-TV), and monitor (OEV 201).
Technique Restoration of occlusion Prior to addressing the condylar fracture, it is essential that the patient’s premorbid occlusion be achieved through the application of Erich-type arch bars. If extracondylar mandibular fractures are present, these are treated first by rigid ORIF as an intact mandibular arch is required when manipulating the condylar fracture later in the procedure, and as one of the main goals of the procedure is to allow immediate postoperative function. Exposure Several minutes prior to making the incision for condylar exposure, the lateral surface of the mandibular ramus ipsilateral to the fracture is infiltrated with a solution of 1% lidocaine and 1:100,000 epinephrine in order to minimize bleeding in the field during exposure and during reduction and fixation. The intraoral incision is similar to that made for a sagittal-splitting osteotomy of the ramus. Using the electro-cautery, an incision is carried down the anterior border of the mandibular ramus, following the oblique line into the buccal sulcus in the region of the first molar. Using a periosteal elevator, the entire lateral surface of the mandibular ramus is exposed in the subperiosteal plane. Because the optical cavity is not a closed space as in intra-abdominal or intrathoracic procedures, mechanical traction must be used to maintain it. This is conveniently achieved by inserting at this point the transbuccal sleeve and its cheek retractor. A point immediately over the palpated location of the posterior aspect of the fracture line is selected and marked, and a small stab incision just through dermis is made 4–5 mm long in the direction of the relaxed skin tension lines. Using a blunt curved hemostat, this incision is deepened by gently spreading the tips of the hemostat parallel to the predicted direction of the facial nerve branches. This dissection is carried through the parotid gland and masseter muscle in order to enter the wound directly over the posterior aspect of the fracture line. The sleeved trocar is inserted and the cheek retractor is mounted on the trocar sleeve to allow the maintenance of the optical cavity by gentle traction. The endoscope can now be placed through the intraoral incision to give an excellent magnified view of the fracture pattern. Reduction The fracture segments ordinarily are telescoped so that they overlap each other to some degree. After achieving maxillo-mandibular fixation (MMF), the fracture segments will need to be distracted so that they can be reduced in an end-on-end fashion. We have found two methods to work well in this situation. One option is to place the patient in tight anterior MMF, using heavy elastics while a 3-mm wedge is placed between the distal molars ipsilateral to the fracture. An assistant then applies cephalic force on the patient’s chin point, thus distracting the posterior ramus inferiorly by lever action (Fig. 3A). Another option is to place a 2-mm screw into the angle of the mandible through a small 4–5 mm incision placed directly inferior to this bony process. A 26-gauge wire is then twisted around this screw and fed through the sheath of a 14-gauge angiocath which is placed percutaneously from a point anterior and inferior to the angle, into the intraoral wound (Fig. 3B). Traction can then be applied by an assistant to distract the distal mandibular segment caudally, while the anterior dentition is held closed by a single 26-gauge MMF wire attached to bone screws placed in
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Fig. 3. Distal fragment control can be achieved by (A) intentionally creating a posterior open bite by placing a wedge in the posterior occlusion with anterior MMF, and (B) percutaneous placement of a traction wire with anterior MMF to apply traction forces to control the posterior vertical ramal position.
the basal bone of the maxilla and mandible. The catheter sheath protects the skin from any possible sawing action of the twisted traction wire. We do not use transcutaneous clamps to provide traction, as they tend to collapse the optical cavity. The proximal segment is then manipulated into a reduced position. This can be a frustrating portion of the operation for the novice and the experienced surgeon alike. Conducting the entire reduction through the intraoral incision is certainly possible, and we have often done it this way in lateral over-ride situations. It is akin, however, to manipulating a fracture through a bottleneck with chopsticks. We have found that in difficult reductions, especially those fractures with medial over-ride, a second per-cutaneous puncture, the same one described above for placing a traction screw, can be very helpful. Through this second puncture, a periosteal elevator can be introduced to add an additional degree of freedom in fracture manipulation. In the case of medial over-ride fracture displacements, by sweeping the elevator carefully along the posterior border of the mandible, the proximal segment can often be guided into place and stabilized. The resulting scar is very small and well hidden in the low-light area below the mandibular border. Fixation Interfragmentary friction resulting from locking of bony interstices of the opposing fracture surfaces maintains the reduction while the surgeon turns his/her attention to fixation. Rigid fixation is achieved using 2-mm mini-plates and screws. The first plate is always placed along the posterior-lateral border of the ramus to take advantage of the thick cortical bone, and the relatively flat surface allows the uncomplicated placement of mini-plates without any bending being necessary. Although the minimum amount of rigid fixation required to allow early function is not precisely known, we prefer to place a second mini-plate anteriorly whenever sufficient bone presents itself because, early on in our series, we had a single case of fracture through a plate. Completion Once fixation is applied and before mucosal closure, the interarch elastics or wires are removed and the mandible is ranged. If the patient does not passively glide into MIP, or displays asymmetrical opening, fixation is removed and the sequence repeated. Noncomminuted fracture lines provide an excellent guide to anatomic reduction. The need to reapply fixation is rarely necessary if cases are properly selected. The incision is then closed with resorbable suture. If midface fractures are present, they are addressed after the condylar fracture and posterior facial height has been restored with EAORIF (Figs. 4–6). All patients are left out of MMF at the end of the case if rigid fixation has been achieved. Patients are instructed in oral hygiene and a soft
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Fig. 4. Patient with complex split left maxillary palatal injury, mandibular symphysis fracture, and lateral over-ride left mandibular subcondylar fracture was surgically repaired. (A) Panorex demonstrates fixation of maxilla, anterior mandible, and subcondylar fracture. (B) Preoperative occlusion. (C) Postrepair occlusion.
Fig. 5. (A) Preoperative three-dimensional CT image shows lateral over-ride of the subcondylar fracture. (B) Endoscopic view of the reduced subcondylar fracture prior to application of plate fixation. (C) Endoscopic view with fixation. (D) Postfixation three-dimensional CT image of the repair.
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Fig. 5 (continued )
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Fig. 6. Serial change in neck line and chin prominence visible with each operative intervention. (A) Maxillary and mandibular fractures not yet repaired. (B) Only anterior symphysis fracture repaired by lag screws. (C ) Anterior symphysis, left subcondylar, and maxillary fractures all repaired.
diet is prescribed. Specific physiotherapy is not prescribed unless a limited interincisal opening is discovered during follow-up. Normal interincisal opening is expected by the eighth postoperative week.
Discussion The principle of anatomic reduction of fracture fragments has achieved nearly universal acceptance throughout the body, including the extracondylar craniofacial skeleton. Surgeons have struggled between their desire to restore the anatomy of traumatized cranio-mandibular joints and their wish to avoid the serious morbidities peculiar to transcutaneous approaches to these
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injuries. When confronted with the subtle deformities associated with malunited condylar fractures, and with the fact that joint dysfunction may not become apparent for many years, many surgeons have been reluctant to offer ORIF of these fractures to their patients. Similarly, many patients refuse treatments that leave visible facial scarring when the seemingly comparatively minor sequelae of malunited fractures are explained to them. Certainly, facial nerve palsy is a devastating complication for both the patient and surgeon. We feel that the EAORIF can offer patients all of the increasingly apparent advantages of anatomic restitution of the condylar region and the immediate function that rigid fixation allows, while avoiding the morbidity of major facial incisions and the risk that extensive dissection around the facial nerve entails. Some surgeons have questioned the role of endoscopy in treating problems of the craniofacial skeleton. Endoscopic reduction and fixation is currently more difficult and time-consuming than traditional open approaches to the condyle. This was also the case with laproscopic cholecystectomy when it first appeared. The advantages to the patient of the laproscopic approach led to the rapid development of technology and training pathways, which soon led to its acceptance as the gold standard in gallbladder surgery. So, too, have the advantages of the endoscopic method sparked intensive clinical investigation and technology development specific to the treatment of condylar fractures. Surgeons who are not familiar with endoscopic methods will require a period of training to master the techniques. Certainly, this effort is justified if we can offer patients the benefits of anatomic reduction with reduced morbidities. It might be said in the end that endoscopic surgery is not difficult; rather, it is difficult to learn. Hopefully, patients will be the beneficiaries of continued clinical and technologic efforts in this exciting new field.
Summary Treatment of mandibular condyle fractures remains a controversial issue. Arguments center on the relative merits of open versus closed treatment. In the past decisions were largely based on philosophy, anecdotal experience, and retrospective case series with short follow-up. Welldesigned studies have now begun to appear in the literature and suggest improved results after open, anatomic reduction and fixation. Many surgeons are still hesitant about liberally applying the open approach due to the resultant facial scarring and the risk of facial nerve injury. Developments in endoscopic technology have recently been applied to facial fracture repair. The endoscopic approach to mandibular condyle fracture repair reduces the risk of facial nerve injury, and dramatically reduces facial scarring, compared with standard open approaches. We feel that the reduced morbidity of the endoscopic approach may allow the benefits of anatomic reduction and rigid fixation to be offered to a larger proportion of patients with mandibular condyle fractures. Technical and technological advances are expected to aid in the dispersal of these techniques in the future.
Suggested readings Dahlstrom L, Kahnberg KE, Lindahl L. 15 year follow-up on condylar fractures. Int J Oral Maxillofac Surg 1989;18: 18–23. Hayward JR, Scott RF. Fractures of the mandibular condyle. J Oral Maxillofacial Surg 1993;51:57–61. Jacobovicz J, Lee C, Trabulsy PP. Endoscopic repair of mandibular subcondylar fractures. Plast Reconstr Surg 1998;101:437–41. Lindahl L, Hollender L. Condylar fractures of the mandible. II. Radiographic study of remodelling processes in the temporomandibular joint. Int J Oral Surg 1977;6:153–65. Silvennoinen U, Raustia AM, Lindqvist C, Oikarinen K. Occlusal and temporo- mandibular joint disorders in patients with unilateral condylar fracture. A prospective one-year study. Int J Oral Maxillofac Surg 1998;27:280–5.
Endoscopic mandibular condyle fracture repair Mark Martin, MD, DMD, Chen Lee, MD, FRCSC* Division of Plastic Surgery, Department of Surgery, McGill University Health Center, McGill University, Montreal, Quebec, 43G 1A4 Canada
The whole history of open reduction and internal fixation (ORIF) of bone fractures can be traced to the twentieth century. The historical evolution of operative treatment of facial fractures has evolved through several phases during this period. Early in the century, closed treatment of facial fractures was pervasive. The development of antibiotics led to increased interest in approaching these fractures surgically. The apogee of this philosophy in the era before rigid internal fixation was the suspension technique championed by Milton Adams, which dominated postWorld War II treatment of these injuries. The basic principle was to suspend fractured segments to the next highest stable landmark in the facial skeleton. These techniques could not control the vertical dimension of the fractured viscerocranium and led to short and retruded post-treatment facies. The development and popularization of rigid internal plating systems by such pioneers as Luhr revolutionized the approach to fractures of the midface and extracondylar mandible. The ability to maintain predictably the accuracy of reductions obtained at surgery opened the door to the extended open reduction techniques developed by such forward-thinking surgeons as Manson and Gruss. Anatomic restitution of the premorbid skeletal anatomy became possible, reproducible, and predictable. The extensive exposures used to achieve these skeletal results have occasionally come at some cost to the soft tissue envelope. The next stage in the advancement of treatment of facial fractures is already under way and revolves around the quest to duplicate the excellence of the skeletal results achieved by extended open reduction and fixation techniques, while minimizing the morbidity suffered by the soft tissue matrix surrounding this framework. The evolution of treatment of subcondylar fractures has paralleled somewhat that of other facial fractures, but it is also distinct in some regards. There has been much satisfaction expressed by many surgeons with the results of closed treatment of subcondylar fractures. Proponents cite simplicity, noninvasiveness, lack of facial scarring, and avoidance of facial nerve damage as benefits of closed over open treatment. Those championing open reduction and internal fixation of these fractures have focused on the benefits of immediate function, improved restoration of facial symmetry and projection, and improved jaw motion resulting from anatomic restoration. Certainly, accurate anatomical reduction of fractures is an accepted standard throughout the body and remainder of the facial skeleton. The clinical impressions of many surgeons in the past has been that the results of closed treatment of subcondylar fractures are generally good; however, well-designed and long-term studies addressing this issue are only now beginning to appear. These studies are starting to demonstrate tangible benefits to accurate reduction and fixation of these fractures. Even so, for any intervention the risks must be weighed against the benefits, and the modest benefits achieved by open techniques have not resulted in the widespread use of these methods which were accepted so rapidly in other facial fracture sites. The main reason for hesitation for most surgeons has centered on the morbidities of the open approach. The two major drawbacks are the inevitable facial scar and the risk of facial nerve damage. Many patients will find the scar objectionable, and abstract discussions of jaw motion abnormalities and late temporomandibular dysfunction will not be convincing to many
* Corresponding author. E-mail address: [email protected] (C. Lee). 1061-3315/03/$ - see front matter Ó 2003 Elsevier Science (USA). All rights reserved. PII: S 1 0 6 1 - 3 3 1 5 ( 0 2 ) 0 0 0 2 5 - 2
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individuals. Many incisions to approach the condyle have been championed as the most aesthetic, yet none is without drawbacks, and all will result in particularly apparent scars in the young and/or dark-skinned patient. Furthermore, even a low percentage of facial nerve injuries are unacceptable to many surgeons and patients alike when weighed against the relative benefits. As clinicians have sought to achieve the benefits of ORIF while minimizing the morbidities associated with the open approach, endoscopic assistance has emerged as an exciting alternative. Endoscopic technology, having been developed and refined by gynecologists and general surgeons, has been a late addition to the treatment of maxillofacial injuries. Though naturally occurring optical cavities in the abdomen and chest lent themselves to the application of endoscopic technology, much anatomic study and surgical innovation was necessary to tap the advantages of this modality for use in the head and neck. The benefits of this effort are particularly evident in the treatment of subcondylar fractures of the mandible. By achieving anatomic reduction and rigid fixation, immediate function is possible; and occlusion, facial symmetry, and jaw motion are normalized. This is achieved while minimizing the morbidities associated with traditional incisional approaches. This article describes the operative technique used since the first description of endoscopic assisted open reduction and internal fixation (EAORIF) of subcondylar fractures.
Anatomy and classification The anatomy of the condylar region is well known to surgeons of the maxillofacial region. The dangers of trans-cutaneous approaches to the condyle are equally well known and are responsible for much of the hesitation many experienced surgeons have in addressing these injuries surgically. All transcutaneous approaches place the facial nerve at risk of iatrogenic transection. The facial nerve has been the subject of a tremendous amount of clinical-anatomic study during the past century. Attempts to group branching patterns into predictable groups abound in the surgical literature. A study of these thorough investigations leads the surgeon to the inevitable conclusion that variability in location of the individual branches is the rule, and that caution is the only reliable guide when traversing the plane of the facial nerve. Nerve stimulators can add some degree of safety in terms of avoiding transactions of major branches. Even so, it is apparent that simply identifying and dissecting out individual branches of the facial nerve may result in paresis of the facial musculature in a sizable minority of cases, as well as occasional permanent nerve dysfunction. Although temporary paresis complicating transcutaneous approaches is often minimized as a source of morbidity by those reporting case series, it is a complication resulting in much anxiety in surgeons and patients alike. Many complex classification systems for fractures of the condylar region have been proposed in the literature over the years. Although these classifications may have value in conducting research studies to separate prognostic factors that may one day guide treatment decisions, none have yet been validated by scientific study and the authors therefore find them unnecessarily cumbersome for clinical use. We use a simple system of classification that is commonly used in the literature and has clinical relevance. We classify fractures as condylar head (intracapsular), condylar neck, and subcondylar (Fig. 1). Condylar head fractures are not treatable by the endoscopic-assisted approach because of their intracapsular nature and lack of bone stock for mini-plate fixation. Fortunately, these high fractures often have excellent maintenance of posterior mandibular height; their consequences instead relate to possible development of late osteoarthritic changes. Condylar neck fractures lie between the intracapsular head and a tangent drawn through the nadir of the sigmoid notch. These fractures may be treatable by the endoscopic approach, depending on the amount of solid bone available for plate application. Subcondylar fractures are most commonly encountered and are usually treatable by EAORIF. We also subclassify fractures as having medial or lateral over-ride. In medial over-ride fractures, the proximal segment has scissored medial to the distal ramal segment; in lateral over-ride fractures, the proximal fragment will present overlapping the distal fragment on its lateral aspect (Fig. 2). The treatment implications of this classification are discussed below. We agree with most other clinicians who refer to separation of the fracture ends as displacement, and to dislodgement of the condylar head out of its position in the mandibular fossa as dislocation.
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Fig. 1. A simplified condylar fracture classification can be used to determine the feasibility of management by endoscopic-assisted methods of surgical repair. Condylar head fractures are not treatable by the endoscopic-assisted approach because of their intercapsular nature and lack of bone stock for mini-plate fixation. Fortunately, these high fractures often have excellent maintenance of posterior mandibular height. Consequences instead relate to possible development of late osteo-arthritic changes. Condylar neck fractures lie between the intracapsular head and a tangent drawn through the nadir of the sigmoid notch. These fractures are technically challenging to repair, as the size of the optical cavity for endoscopic repair is very limited. Most fractures present as subcondylar fractures extending below the nadir of the sigmoid notch.
Indications and contraindications Lists of indications and contraindications for open treatment abound in the literature. Many of these lists are mostly unhelpful to the clinician faced with a typical fracture of the condyle as they concentrate on situations that occur only very rarely, such as intracranial displacement. Our indications for approaching condylar fractures by EAORIF relate to the functional and aesthetic consequences of the fracture. Loss of posterior mandibular height on one side results
Fig. 2. (A, B) Subcondylar fractures can be further subclassifed as having medial or lateral over-ride. (C,D) Medial override fractures, where the proximal segment has scissored medial to the distal ramal segment, are extremely difficult to access and repair as the proximal condylar pole is ‘‘hidden’’ by the telescoped ascending ramus. Most adult fractures present with lateral over-ride at the ramal fracture interface. As the proximal fragment will present overlapping the distal fragment on its lateral aspect, the proximal condylar pole is more accessible to endoscopic manipulation and repair.
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in an asymmetry of the cranio-mandibular articulation. The cranio-mandibular joint is unique in the body by being a ginglymodiarthrodial joint, and in particular its bilateral nature. Many individuals are capable of an impressive degree of neuromuscular adaptation after subcondylar malunions, and they will learn to force themselves into maximal intercuspal position (MIP). This has been taken by many clinicians to equate to an acceptable result, but we would submit that when there is a loss of posterior mandibular height, a spectrum of predictable sequelae result. People find themselves in MIP for a very small portion of the day; instead, their teeth are most often separated in function or in an unconstrained position at the vertical dimension of rest (VDR), with several millimeters between their teeth. When at VDR, the functional matrix seeks to position the condyle in the mandibular fossa, and thus the anatomic asymmetry of the mandible becomes manifest at rest as the chin point deviates toward the side with the malunion. Likewise, in functional movements the deranged cranio-mandibular articulation is even more apparent as deviation of the chin point to the mal-united side worsens during attempts at maximal opening, as translational movements are often disturbed by the altered joint mechanics. Also visible clinically in these injuries is a loss of chin projection in the sagittal plane, resulting from a clockwise rotation of the mandible from a loss of posterior mandibular height. This is most profound in the bilateral case which more often overwhelms the patient’s ability to adapt by neuromuscular means and results in an anterior open bite in a higher percentage of cases treated by closed means. Though aware of the shortcomings of closed treatment, we also recognize that some fractures are not amenable to EAORIF. Fractures of the growing condylar region have been demonstrated to possess an impressive ability to remodel, and we therefore treat these injuries closed. Undisplaced fractures have been demonstrated to have good results following closed treatment, and we do not treat these injuries with EAORIF. Because our technique is dependent on accurate anatomic reduction of fracture lines, and also relies on some degree of interfragmentary friction to stabilize the reduction during fixation, severe comminution is considered a contraindication to using this technique. Our general indications to offer EAORIF to patients are displaced and/or dislocated fractures of the extracapsular condyle region, demonstrating some combination of malocclusion, loss of chin projection, and asymmetry at rest and/or in function, which do not display severe comminution, in adults without medical contraindications for surgery.
Diagnosis and imaging Patients presenting with signs and symptoms of craniofacial trauma to the emergency room often undergo a series of plane radiographs. It is our belief that plain radiographs, although often supplying sufficient detail to diagnose craniofacial fractures, do not provide sufficient detail to allow thorough treatment planning of these injuries. We feel this holds true for condylar fractures being considered for EAORIF as well. Therefore, if a patient presents with physical signs and symptoms suggestive of a condylar fracture, we proceed directly to fine-cut CT. These scans are acquired at 1.5 mm intervals in the axial plane, which allows for sufficient detail in the reformatted coronal images. Three-dimensional reformatted images require no extra radiation exposure to the patient and can be easily and routinely generated by most modern workstations, and they provide an easy-to-interpret overview of the fracture relations that may be helpful in planning the operation. With some experience in EAORIF of condylar fractures, surgeons soon develop the ability to select by inspection of CT scans those fractures with enough proximal bone stock, and without too much comminution, to be successfully treated by this method. When viewing the images, it is also important to note the presence of medial over-ride, which portends a more difficult reduction and the possible necessity for additional operative maneuvers, as discussed below.
Equipment Originally in the development of EAORIF of condylar fractures, equipment had to be adapted from that already in use for other purposes. Now, instrument sets specifically designed
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for this method are commercially available (Synthes Maxillofacial, West Chester, PA, USA). Here, we describe the equipment currently used by the authors, which is similar to equipment available in most major medical centers. The endoscope we use is a 4-mm diameter, 30 -angle scope (Karl Storz, Tuttlingten, Germany). A 4-mm endoscope-mounted retractor is useful in maintaining the optical cavity (Karl Storz). The endoscopic image is displayed on a video system (Olympus America, Inc., Lake Success, NY) consisting of a three-chip camera (Olympus XLS), camera converter (Olympus 3C-TV), and monitor (OEV 201).
Technique Restoration of occlusion Prior to addressing the condylar fracture, it is essential that the patient’s premorbid occlusion be achieved through the application of Erich-type arch bars. If extracondylar mandibular fractures are present, these are treated first by rigid ORIF as an intact mandibular arch is required when manipulating the condylar fracture later in the procedure, and as one of the main goals of the procedure is to allow immediate postoperative function. Exposure Several minutes prior to making the incision for condylar exposure, the lateral surface of the mandibular ramus ipsilateral to the fracture is infiltrated with a solution of 1% lidocaine and 1:100,000 epinephrine in order to minimize bleeding in the field during exposure and during reduction and fixation. The intraoral incision is similar to that made for a sagittal-splitting osteotomy of the ramus. Using the electro-cautery, an incision is carried down the anterior border of the mandibular ramus, following the oblique line into the buccal sulcus in the region of the first molar. Using a periosteal elevator, the entire lateral surface of the mandibular ramus is exposed in the subperiosteal plane. Because the optical cavity is not a closed space as in intra-abdominal or intrathoracic procedures, mechanical traction must be used to maintain it. This is conveniently achieved by inserting at this point the transbuccal sleeve and its cheek retractor. A point immediately over the palpated location of the posterior aspect of the fracture line is selected and marked, and a small stab incision just through dermis is made 4–5 mm long in the direction of the relaxed skin tension lines. Using a blunt curved hemostat, this incision is deepened by gently spreading the tips of the hemostat parallel to the predicted direction of the facial nerve branches. This dissection is carried through the parotid gland and masseter muscle in order to enter the wound directly over the posterior aspect of the fracture line. The sleeved trocar is inserted and the cheek retractor is mounted on the trocar sleeve to allow the maintenance of the optical cavity by gentle traction. The endoscope can now be placed through the intraoral incision to give an excellent magnified view of the fracture pattern. Reduction The fracture segments ordinarily are telescoped so that they overlap each other to some degree. After achieving maxillo-mandibular fixation (MMF), the fracture segments will need to be distracted so that they can be reduced in an end-on-end fashion. We have found two methods to work well in this situation. One option is to place the patient in tight anterior MMF, using heavy elastics while a 3-mm wedge is placed between the distal molars ipsilateral to the fracture. An assistant then applies cephalic force on the patient’s chin point, thus distracting the posterior ramus inferiorly by lever action (Fig. 3A). Another option is to place a 2-mm screw into the angle of the mandible through a small 4–5 mm incision placed directly inferior to this bony process. A 26-gauge wire is then twisted around this screw and fed through the sheath of a 14-gauge angiocath which is placed percutaneously from a point anterior and inferior to the angle, into the intraoral wound (Fig. 3B). Traction can then be applied by an assistant to distract the distal mandibular segment caudally, while the anterior dentition is held closed by a single 26-gauge MMF wire attached to bone screws placed in
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Fig. 3. Distal fragment control can be achieved by (A) intentionally creating a posterior open bite by placing a wedge in the posterior occlusion with anterior MMF, and (B) percutaneous placement of a traction wire with anterior MMF to apply traction forces to control the posterior vertical ramal position.
the basal bone of the maxilla and mandible. The catheter sheath protects the skin from any possible sawing action of the twisted traction wire. We do not use transcutaneous clamps to provide traction, as they tend to collapse the optical cavity. The proximal segment is then manipulated into a reduced position. This can be a frustrating portion of the operation for the novice and the experienced surgeon alike. Conducting the entire reduction through the intraoral incision is certainly possible, and we have often done it this way in lateral over-ride situations. It is akin, however, to manipulating a fracture through a bottleneck with chopsticks. We have found that in difficult reductions, especially those fractures with medial over-ride, a second per-cutaneous puncture, the same one described above for placing a traction screw, can be very helpful. Through this second puncture, a periosteal elevator can be introduced to add an additional degree of freedom in fracture manipulation. In the case of medial over-ride fracture displacements, by sweeping the elevator carefully along the posterior border of the mandible, the proximal segment can often be guided into place and stabilized. The resulting scar is very small and well hidden in the low-light area below the mandibular border. Fixation Interfragmentary friction resulting from locking of bony interstices of the opposing fracture surfaces maintains the reduction while the surgeon turns his/her attention to fixation. Rigid fixation is achieved using 2-mm mini-plates and screws. The first plate is always placed along the posterior-lateral border of the ramus to take advantage of the thick cortical bone, and the relatively flat surface allows the uncomplicated placement of mini-plates without any bending being necessary. Although the minimum amount of rigid fixation required to allow early function is not precisely known, we prefer to place a second mini-plate anteriorly whenever sufficient bone presents itself because, early on in our series, we had a single case of fracture through a plate. Completion Once fixation is applied and before mucosal closure, the interarch elastics or wires are removed and the mandible is ranged. If the patient does not passively glide into MIP, or displays asymmetrical opening, fixation is removed and the sequence repeated. Noncomminuted fracture lines provide an excellent guide to anatomic reduction. The need to reapply fixation is rarely necessary if cases are properly selected. The incision is then closed with resorbable suture. If midface fractures are present, they are addressed after the condylar fracture and posterior facial height has been restored with EAORIF (Figs. 4–6). All patients are left out of MMF at the end of the case if rigid fixation has been achieved. Patients are instructed in oral hygiene and a soft
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Fig. 4. Patient with complex split left maxillary palatal injury, mandibular symphysis fracture, and lateral over-ride left mandibular subcondylar fracture was surgically repaired. (A) Panorex demonstrates fixation of maxilla, anterior mandible, and subcondylar fracture. (B) Preoperative occlusion. (C) Postrepair occlusion.
Fig. 5. (A) Preoperative three-dimensional CT image shows lateral over-ride of the subcondylar fracture. (B) Endoscopic view of the reduced subcondylar fracture prior to application of plate fixation. (C) Endoscopic view with fixation. (D) Postfixation three-dimensional CT image of the repair.
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Fig. 5 (continued )
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Fig. 6. Serial change in neck line and chin prominence visible with each operative intervention. (A) Maxillary and mandibular fractures not yet repaired. (B) Only anterior symphysis fracture repaired by lag screws. (C ) Anterior symphysis, left subcondylar, and maxillary fractures all repaired.
diet is prescribed. Specific physiotherapy is not prescribed unless a limited interincisal opening is discovered during follow-up. Normal interincisal opening is expected by the eighth postoperative week.
Discussion The principle of anatomic reduction of fracture fragments has achieved nearly universal acceptance throughout the body, including the extracondylar craniofacial skeleton. Surgeons have struggled between their desire to restore the anatomy of traumatized cranio-mandibular joints and their wish to avoid the serious morbidities peculiar to transcutaneous approaches to these
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injuries. When confronted with the subtle deformities associated with malunited condylar fractures, and with the fact that joint dysfunction may not become apparent for many years, many surgeons have been reluctant to offer ORIF of these fractures to their patients. Similarly, many patients refuse treatments that leave visible facial scarring when the seemingly comparatively minor sequelae of malunited fractures are explained to them. Certainly, facial nerve palsy is a devastating complication for both the patient and surgeon. We feel that the EAORIF can offer patients all of the increasingly apparent advantages of anatomic restitution of the condylar region and the immediate function that rigid fixation allows, while avoiding the morbidity of major facial incisions and the risk that extensive dissection around the facial nerve entails. Some surgeons have questioned the role of endoscopy in treating problems of the craniofacial skeleton. Endoscopic reduction and fixation is currently more difficult and time-consuming than traditional open approaches to the condyle. This was also the case with laproscopic cholecystectomy when it first appeared. The advantages to the patient of the laproscopic approach led to the rapid development of technology and training pathways, which soon led to its acceptance as the gold standard in gallbladder surgery. So, too, have the advantages of the endoscopic method sparked intensive clinical investigation and technology development specific to the treatment of condylar fractures. Surgeons who are not familiar with endoscopic methods will require a period of training to master the techniques. Certainly, this effort is justified if we can offer patients the benefits of anatomic reduction with reduced morbidities. It might be said in the end that endoscopic surgery is not difficult; rather, it is difficult to learn. Hopefully, patients will be the beneficiaries of continued clinical and technologic efforts in this exciting new field.
Summary Treatment of mandibular condyle fractures remains a controversial issue. Arguments center on the relative merits of open versus closed treatment. In the past decisions were largely based on philosophy, anecdotal experience, and retrospective case series with short follow-up. Welldesigned studies have now begun to appear in the literature and suggest improved results after open, anatomic reduction and fixation. Many surgeons are still hesitant about liberally applying the open approach due to the resultant facial scarring and the risk of facial nerve injury. Developments in endoscopic technology have recently been applied to facial fracture repair. The endoscopic approach to mandibular condyle fracture repair reduces the risk of facial nerve injury, and dramatically reduces facial scarring, compared with standard open approaches. We feel that the reduced morbidity of the endoscopic approach may allow the benefits of anatomic reduction and rigid fixation to be offered to a larger proportion of patients with mandibular condyle fractures. Technical and technological advances are expected to aid in the dispersal of these techniques in the future.
Suggested readings Dahlstrom L, Kahnberg KE, Lindahl L. 15 year follow-up on condylar fractures. Int J Oral Maxillofac Surg 1989;18: 18–23. Hayward JR, Scott RF. Fractures of the mandibular condyle. J Oral Maxillofacial Surg 1993;51:57–61. Jacobovicz J, Lee C, Trabulsy PP. Endoscopic repair of mandibular subcondylar fractures. Plast Reconstr Surg 1998;101:437–41. Lindahl L, Hollender L. Condylar fractures of the mandible. II. Radiographic study of remodelling processes in the temporomandibular joint. Int J Oral Surg 1977;6:153–65. Silvennoinen U, Raustia AM, Lindqvist C, Oikarinen K. Occlusal and temporo- mandibular joint disorders in patients with unilateral condylar fracture. A prospective one-year study. Int J Oral Maxillofac Surg 1998;27:280–5.