- Email: [email protected]
Mandibular Subcondylar Fractures
Chapter
38
Mandibular Subcondylar Fractures Larry L. Cunningham, Jr., Aaron Sterling Card
T
he most common site of all mandibular fractures is the condylar or subcondylar region, where 9% to 45% of mandibular fractures occur.1,2 The volume of debate about diagnosis and management of injuries to the temporomandibular joint (TMJ) sheds light on the difficulty associated with managing and repairing these complex injuries.3-5
ETIOPATHOGENESIS/CAUSATIVE FACTORS The etiology of subcondylar fractures mirrors that of most facial trauma. In adults, the most common causes of subcondylar fractures of the mandible are motor vehicle accidents, interpersonal violence,
work-related incidents, sporting accidents, and falls. In children, the most common causes are falls and bicycle accidents, although motor vehicle accidents also play an important role.1,2,6
PATHOLOGIC ANATOMY Subcondylar fractures of the mandible are defined as fractures below the level of the most inferior point on the sigmoid notch (Fig. 38-1).7 Depending on the circumstances, condylar neck fractures may be treated as subcondylar fractures; displacement and malocclusion in the setting of a long condylar neck (the ability to place at least two screws in the segment) would qualify. Historically, two systems have been developed for the classification of subcondylar fractures: the Lindahl system8-11 and the MacLennan system12
Mandibular Subcondylar Fractures
299
Mandibular condyle Neck of condyle
Fig. 38-1 n Lateral view of bones of the temporomandibular joint. (From Liebgott B: The anatomical basis of dentistry, ed 3, St. Louis, 2011, Mosby.)
BOX 38-1
The Lindahl System8-12
The Lindahl system classifies subcondylar fractures according to their anatomic location and the specific relationship between the fractured condyle and the glenoid fossa. The anatomic location of the fracture is described first. The most superior fracture is in the condylar head, which means that the fracture probably lies in the capsule of the temporomandibular joint; the second is a fracture in the thin neck of the condyle. The most inferior fracture lies in the subcondylar region below the anatomic neck and extends to the inferior portion of the ramus. Relationship of the condylar segment to the mandibular fragment: 1. Nondisplaced. 2. Deviated: angulation of the condylar head without dislocation of the fractured segments. 3. Displaced with medial or lateral overlap. The fractured condylar head lies either medial or lateral to the distal segment, with overlap. A medial position is more common because of the attachment and traction of the lateral pterygoid. Relationship between the condylar head and the glenoid fossa: 1. Nondisplaced. 2. Displaced: the condylar head remains in the fossa, but the joint space is altered. 3. Dislocation. The condylar head lies completely outside the anatomic fossa. This position requires rupture of the capsule.
(Boxes 38-1 and 38-2). The main objectives of these classifications systems are to describe the relationship of the condyle to the glenoid fossa and the relationship between the fractured proximal and distal segments. The condylar head can remain in the fossa, can be dis located out of the fossa either medially or laterally, or in rare cases can be dislocated into a fractured fossa. Fractured subcondylar segments can be nondisplaced (hairline fracture); alternatively, the proximal segment may be displaced either medially or laterally relative to the distal segment. Most of these fractures will be described as closed fractures unless they are associated with deep facial lacerations.
DIAGNOSTIC STUDIES Panoramic radiographs and Towne projection radiographs are effective methods of evaluating the subcondylar region of the mandible. However, computed tomography (CT) is currently the state of the
BOX 38-2
The MacLennan System12
Type I fracture, nondisplaced. Type II fracture, deviated. Angulation without overlap or separation. Greenstick fractures are included in this category. Type III fracture, displaced. This fracture displays overlap between the proximal and distal segments. Type IV fracture, dislocated. The condylar head leaves the capsule and lies outside the glenoid fossa. The location could be medial, lateral, anterior, or posterior.
art for detecting subcondylar fractures of the mandible. Threedimensional reconstructions of CT data offer the surgeon invaluable information about the position of the fractured segments, thereby allowing the most accurate planning of fracture management.13
TREATMENT/RECONSTRUCTIVE GOALS The goals of treating any type of trauma are to restore pain-free, premorbid form and function. With respect to subcondylar fractures of the mandible, the goal is restoration or maintenance of facial symmetry and posterior mandibular height. Treatment should be completed without injury to the parotid gland or the facial nerve and, preferably, without obvious scarring. Ideal restoration of function after treatment of a subcondylar fracture includes re-establishment of maximum mandibular movements: a maximum incisal opening (MIO) of 40 mm without deviation, lateral excursive movements of greater than 5 mm to the right and left, and the absence of signs or symptoms of temporomandibular disorder.
SPECIFIC TREATMENT AND TECHNIQUES SURGICAL ANATOMY TO CONSIDER The facial nerve exits the skull from the stylomastoid foramen and passes obliquely inferiorly and laterally until it enters the parotid gland. The common facial divisions of the nerve are the temporal, zygomatic, buccal, marginal mandibular, and cervical divisions. The branches most at risk during a transfacial approach to the subcondylar region are the buccal and marginal mandibular branches; those most at risk during an approach to the TMJ or an intracapsular fracture are the zygomatic and temporal branches.
300
Current Therapy in Oral and Maxillofacial Surgery
The confluence of the superficial temporal vein and the maxillary vein is called the retromandibular vein. This vascular structure can be the source of substantial bleeding deep to the ramus and the neck of the condyle because it descends just posterior to the ramus of the mandible through the parotid gland. This vein is lateral to the external carotid artery.
CLOSED MANAGEMENT Closed management3 is performed more than any other type of management because of its ease and long history of use. It is indicated for very specific subcondylar fractures, two of which are greenstick fractures in pediatric patients and nondisplaced fractures that do not “fall back”7 under anesthesia in adults. In addition, closed management is indicated for the treatment of any patient who refuses surgery as an option. The technique can be applied variably: as a liquid diet (as in the situation with greenstick fractures in pediatric patients), as maxillomandibular fixation (MMF) with arch bars and wires, or as fixation with arch bars and elastic bands. Likewise, elastic bands may be used either in a light, guiding fashion or in a heavy fashion, in which case they are very similar to wire fixation. Although closed management may still be commonplace, it cannot be considered the state of the art. It has even been shown that treatment by MMF may be associated with a higher incidence of temporomandibular dysfunction postoperatively than seen with other types of treatment and that closed treatment may not prevent further displacement of the fractured subcondylar segments.14,15 However, closed management can avoid the risks associated with general anesthesia, facial nerve injury, parotid injury, and scarring and can also shorten the duration of soft tissue swelling after the injury.
OPEN REDUCTION WITH INTERNAL FIXATION Indications Zide and Kent presented the absolute and relative indications for open reduction of mandibular condylar fractures (Box 38-3).16 Since their presentation of the clinical standard, many improvements have
BOX 38-3
Zide and Kent’s Indications for Open Reduction of Condylar Fractures16
Absolute indications (pertain to children as well as to adults): 1. Displacement into the middle cranial fossa 2. Impossibility of obtaining adequate occlusion by closed reduction 3. Lateral extracapsular displacement of the condyle 4. Invasion by a foreign body (e.g., gunshot wound) Relative indications: 1. Bilateral condylar fractures in an edentulous patient when a splint is unavailable or splinting is impossible because of atrophy of the alveolar ridge 2. Unilateral or bilateral condylar fractures for which splinting is not recommended for medical reasons or when adequate physiotherapy is impossible 3. Bilateral condylar fractures associated with comminuted midfacial fractures 4. Bilateral condylar fractures and associated gnathologic problems such as retrognathia or prognathism, open bite with periodontal problems or lack of posterior support, loss of multiple teeth and later need for elaborate reconstruction, bilateral fractures and unstable occlusion because of orthodontics, and unilateral condylar fracture with an unstable fracture base
been made in rigid internal fixation and endoscopic application to craniofacial fractures, and these improvements have allowed expanded indications for open reduction and internal fixation (ORIF) of subcondylar fractures.10 More recent studies have focused on the complications associated with open and closed treatment of subcondylar fractures of the mandible (Box 38-4).3,4,14,15,17-20 The international principles guiding fracture management today include anatomic reduction of fractured segments, functionally stable internal fixation, and early mobilization; these principles have been well established in the dental literature.21,22 The goal of fracture management is normal, pain-free function. As all surgeons know, the decision whether to operate is not always as clear as the guiding principles would suggest. Surgeons should discuss the following important points with the patient when deciding whether to open a subcondylar fracture: the severity of the fracture, the amount of disability that is likely to occur, the relative risks to important
BOX 38-4
Considerations for Approach to Subcondylar Fractures
In 2004, Edward Ellis III, DDS, gave a presentation at the Symposium on Management of Subcondylar Fractures; Historical Perspectives and New Horizons. He addressed the historical aspects of subcondylar fracture management and readdressed his indications for open surgical management in light of advancing techniques for stable internal fixation. He acknowledged the lack of universal agreement among surgeons with regard to management protocols, yet stated that most fractures may be managed satisfactorily with closed techniques. He summarized his indications for open treatment: 1. Displacement of the condyle into the middle cranial fossa (with or without fracture) 2. Lateral extracapsular displacement of the condyle (with or without fracture) 3. Impossibility of obtaining proper occlusion with closed techniques 4. Condylar fractures associated with comminuted fractures at or above Le Fort I In addition, Ellis discussed the relative indications for open and closed management. He stated that surgeons, at their own discretion, may use either the open or closed method, depending on their own philosophy and experience. Factors to be considered when deciding between open and closed management include 1. Loss of ramus height beyond acceptable esthetic limits or loss of the posterior dentition that would ordinarily assist in maintaining height of the ramus 2. The skeletal age of the patient (Children’s jaws can adapt to a new condylar position, or frank neocondylar synthesis may occur.) 3. Ability to attain stable fixation (If a fracture is located high on the condylar neck or in the capsule, nonsurgical management may be more appropriate. Some patients’ medical condition may not be considered stable enough to allow them to undergo either open or closed management, or they may have a strong desire to avoid intermaxillary fixation and would therefore chose an alternative management method.) 4. Associated fractures, including bilateral condylar fractures, especially those that are displaced (Opening at least one fracture may improve occlusal outcomes.) 5. State of the patient’s dentition (When dentition is incomplete, it may be impossible to maintain the position of the mandible when a new articulation is established. Open treatment may be the better option for preventing posterior vertical collapse or the need for additional splint fabrication to maintain stability.)
Mandibular Subcondylar Fractures anatomic structures, the likelihood of scarring, and the patient’s preferences. The patient should be made aware of the potential complications associated with subcondylar fractures, including changes in occlusion, pain and temporomandibular dysfunction, and possible alterations in the symmetry of the face.4,7,15,18 Transfacial approaches to the subcondylar region are favored because they allow direct access and visualization, thereby increasing the surgeon’s ability to achieve anatomic reduction of the fracture. Surgical complications that are associated with open treatment of condylar process fractures and that lead to permanent dysfunction or deformity are generally uncommon.17 However, some of these risks, such as facial nerve injury, sialocele, infection, and scarring, though uncommon, are serious and may be difficult to manage. Still, all of these approaches can be technically challenging, and learning curves should be expected. The most popular approaches are the submandibular approach and the retromandibular approach.23 The senior author prefers the retromandibular approach for its proximity to the fracture site (Fig. 38-2). The indications for endoscopically assisted ORIF of subcon dylar fractures are the same as those for the open transfacial approaches. However, because the potential difficulty of the endoscopically assisted approach is considerably increased when comminuted fractures are present, its use may be contraindicated in such cases.8
B
A
D
301
The intraoral approach without the benefit of an endoscope was first reported by Jeter and co-authors. This approach reduced the risk for facial nerve damage and avoided the large facial scars associated with transfacial approaches; it also allowed the surgeon to accurately reduce and fixate the fracture while maintaining the patient’s proper occlusion.24 However, the difficulty associated with applying this technique without the advantage of an endoscope limited the number of patients who were able to benefit from open reduction of the condyle. The advantages of the endoscope have been described more recently and have furthered the argument for the endoscopic approach with intraoral access, an approach associated with minimal complications.8,25 The technique has a steep learning curve, but the time required for applying this technique decreases after sufficient experience has been gained. Careful patient selection is essential.13,26,27 The endoscopically assisted approach can allow restoration of the relationship between the condyle and the mandible and can re-establish function to a state that is as close as possible to the preinjury condition with minimal risk for facial nerve damage or facial scarring (Fig. 38-3).
Contraindications High condylar neck fractures (i.e., those that leave a segment that is too short to accept two screws) and condylar head fractures should not be treated with ORIF. Displaced subcondylar fractures with
C
E Fig. 38-2 n Extraoral approach to a mandibular subcondylar fracture via a retromandibular incision. A, Patient markings. B, Visualization of the fracture. The superior retractor allows visualization of the distal fractured stump of the proximal segment. C, Fixation plate in place after fracture reduction. D, Six weeks postoperatively with a maximum incisal opening of 40 mm. E, Postoperative panoramic radiograph.
302
Current Therapy in Oral and Maxillofacial Surgery
A
B
C
D
E
F Fig. 38-3 n Endoscopically assisted approach to a mandibular subcondylar fracture. A, Preoperative panoramic radiograph. B, Preoperative Towne view showing significant lateral over-ride of the left subcondylar fracture. C, Endoscopic view of the distal fractured stump of the proximal segment. D, Endoscopic view of fixation placement. E, Postoperative panoramic radiograph. F, Postoperative maximum incisal opening of 50 mm to the maxillary edentulous ridge.
medial override of the proximal segment are the most difficult to reduce adequately with an endoscopically assisted approach. A surgical procedure is justified only when the condylar segments are displaced. Fractures that are unlikely to affect occlusion or facial height (greenstick fractures or medial pole fractures) should not be opened.7
POSTOPERATIVE CARE Postoperative care after repair of subcondylar fractures should consist of the placement of light elastic bands for occlusal guidance; these bands should remain in place for 7 to 14 days. Generally, a full liquid diet is recommended for 3 days after surgery, followed
Mandibular Subcondylar Fractures
303
by a soft mechanical diet for the next 3 to 4 weeks. Early mobilization of the joint is important so that ankylosis can be avoided. After an initial healing period of 2 weeks, patients are encouraged to begin their own physical therapy to increase MIO to the postoperative goal of 40 mm. Available commercial devices can assist in this rehabilitation; however, stacked tongue blades offer the patients an inexpensive and effective guide. Patients are encouraged to use tongue blades to assist in their rehabilitation four to five times during the day for a total of 30 minutes of stretching per day. In addition, they are asked to attempt to add one tongue blade to the stack every day or two until they achieve an MIO of 40 mm.
condyle to remodel allow greater success of nonsurgical therapy in children than in adults. The general consensus is that nonsurgical management is the best option for children until they reach the age of 12 years, until there is a departure from mixed dentition, or until puberty begins.3,8,16 Conservative treatment may consist of a liquid diet only or a brief period of MMF (1 to 2 weeks) with arch bars and heavy elastic bands. Following this short period of inactivity, active function and joint physiotherapy are important to reduce the formation of scar tissue and prevent TMJ fibrosis or ankylosis.6
MANAGEMENT CONTROVERSY
The authors would like to thank Flo Witte for her expert editorial assistance.
Mobilization and rehabilitation are the keys in treating subcondylar fractures.28 Management of subcondylar fractures is controversial because many of these fractures will heal with acceptable results after being treated by MMF. Avoidance of surgery certainly alleviates the risk for surgical complications. In addition, using shorter periods of MMF, 3 to 4 weeks rather than 6 weeks, creates less of a burden for the patient. Although MMF is faster and less expensive than ORIF,29 it does not eliminate all complications and indeed may result in malocclusion, which requires a secondary surgical procedure, most often sagittal split osteotomy. Other potential complications associated with MMF are TMJ dysfunction, malo cclusion, and altered facial symmetry.4,14,15,18 Although rigid internal fixation does not eliminate the importance of rehabilitation for increasing the patient’s MIO, it is certainly associated with shorter convalescence, particularly for more difficult, severely displaced and dislocated fractures that cause substantial disturbances in occlusion, loss of ramal height, and facial asymmetry, as well as for multiple facial fractures. ORIF may also be the treatment of choice when MMF is not recommended, such as for patients with certain co-morbid conditions (learning disabilities, pulmonary diseases, seizure disorders).18,30 Ideally, surgeons would be adequately trained to provide alternative methods of care. When offered the option of surgery and rehabilitation or the option of any period of MMF, many patients choose the surgical procedure despite its potential risks.
FRACTURES IN CHILDREN Subcondylar fractures in children are different from those in adults for a number of reasons. The presence of primary or mixed dentition, remaining growth potential, and the great capacity for the childhood
ACKNOWLEDGMENT
PEARLS AND PITFALLS • When subcondylar fractures are treated with MMF, close follow-up and rehabilitation are very important. • Minor occlusal discrepancies after treatment can be treated with elastic bands or orthodontics and with vigilance in aiding the patient to achieve an MIO of 40 mm. • Treating a patient with MMF when there is substantial overlap of the fractured segments or rotating the condylar segment during pretreatment imaging may be associated with a risk for malocclusion after treatment. • When multiple fractures of the mandible are treated with ORIF of the subcondylar fracture, the mandible should be reduced and fixated in an anterior to posterior direction; the most anterior fracture should be plated first. • MMF should not be in place when the subcondylar segment is reduced. • MMF can be used before screw placement if the segments remain reduced. • Endoscopic approaches are technique-sensitive, and the surgical instruments are unique. • Surgeons should select early cases carefully so that they can familiarize themselves with the techniques. • Fractures with lateral override are much easier to treat with endoscopic guidance, whereas medially displaced segments are more difficult to treat with this technique. • The retromandibular approach to the subcondylar region is associated with a high risk for encountering the facial nerve. • Blunt dissection through the parotid is mandatory, and the assistance of a nerve stimulator is recommended.
REFERENCES 1. Ellis E 3rd, Moos KF, el-Attar A: Ten years of mandibular fractures: an analysis of 2,137 cases, Oral Surg Oral Med Oral Pathol 59:120-129, 1985. 2. Haug RH, Prather J, Indresano AT: An epidemiologic survey of facial fractures and concomitant injuries, J Oral Maxillofac Surg 48:926-932, 1990. 3. Ellis E, Throckmorton GS: Treatment of mandibular condylar process fractures: biological considerations, J Oral Maxillofac Surg 63:115-134, 2005. 4. Ellis E 3rd, Simon P, Throckmorton GS: Occlusal results after open or closed treatment of fractures of the mandibular condylar
process, J Oral Maxillofac Surg 58:260-268, 2000. 5. Nussbaum ML, Laskin DM, Best AM: Closed versus open reduction of mandibular condylar fractures in adults: a meta-analysis, J Oral Maxillofac Surg 66:1087-1092, 2008. 6. Miller RI, McDonald DK: Remodeling of bilateral condylar fractures in a child, J Oral Maxillofac Surg 44:1008-1010, 1986. 7. Ellis E 3rd: Method to determine when open treatment of condylar process fractures is not necessary, J Oral Maxillofac Surg 67:16851690, 2009. 8. Lindahl L, Hollender L: Condylar fractures of the mandible. II. A radiographic study of
remodeling processes in the temporomandibular joint, Int J Oral Surg 6:153-165, 1977. 9. Lindahl L: Condylar fractures of the mandible. IV. Function of the masticatory system, Int J Oral Surg 6:195-203, 1977. 10. Lindahl L: Condylar fractures of the mandible. III. Positional changes of the chin, Int J Oral Surg 6:166-172, 1977. 11. 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 6:1221, 1977.
304
Current Therapy in Oral and Maxillofacial Surgery
12. MacLennan W: Consideration of 180 cases of typical fractures of the mandibular condylar process, Br J Plast Surg 5:122-128, 1952. 13. Kellman RM, Cienfuegos R: Endoscopic approaches to subcondylar fractures of the mandible, Facial Plast Surg 25:23-28, 2009. 14. Ellis E 3rd, Palmieri C, Throckmorton G: Further displacement of condylar process fractures after closed treatment, J Oral Maxillofac Surg 57:1307-1316, discussion 1316-1317, 1999. 15. Haug RH, Assael LA: Outcomes of open versus closed treatment of mandibular subcondylar fractures, J Oral Maxillofac Surg 59:370-375, discussion 375-376, 2001. 16. Zide MF, Kent JN: Indications for open reduction of mandibular condyle fractures, J Oral Maxillofac Surg 41:89-98, 1983. 17. Ellis E 3rd, McFadden D, Simon P, et al: Surgical complications with open treatment of mandibular condylar process fractures, J Oral Maxillofac Surg 58:950-958, 2000. 18. Ellis E 3rd, Throckmorton G: Facial symmetry after closed and open treatment of fractures of the mandibular condylar process, J Oral Maxillofac Surg 58:719-728, discussion 729-730, 2000.
19. Ellis E 3rd, Throckmorton GS: Bite forces after open or closed treatment of mandibular condylar process fractures, J Oral Maxillofac Surg 59:389-395, 2001. 20. Ellis E 3rd, Throckmorton GS, Palmieri C: Open treatment of condylar process fractures: assessment of adequacy of repositioning and maintenance of stability, J Oral Maxillofac Surg 58:27-35, discussion 35, 2000. 21. Greenberg AM, editor: Craniomaxillofacial fractures: principles of internal fixation using the AO/ASIF technique. New York, 1993, Springer-Verlag. 22. Prein J, editor: Manual of internal fixation in the cranio-facial skeleton: techniques recommended by the AO/ASIF maxillofacial group. New York, 1998, Springer-Verlag. 23. Chossegros C, Cheynet F, Blanc JL, et al: Short retromandibular approach of subcondylar fractures: clinical and radiologic long-term evaluation, Oral Surg Oral Med Oral Pathol Oral Radiol Endod 82:248-252, 1996. 24. Jeter TS, Van Sickels JE, Nishioka GJ: Intraoral open reduction with rigid internal fixation of mandibular subcondylar fractures, J Oral Maxillofac Surg 46:1113-1116, 1988.
25. Kellman RM: Endoscopically assisted repair of subcondylar fractures of the mandible: an evolving technique, Arch Facial Plast Surg 5:244-250, 2003. 26. Schmelzeisen R, Cienfuegos-Monroy R, Schon R et al: Patient benefit from endoscopically assisted fixation of condylar neck fractures—a randomized controlled trial, J Oral Maxillofac Surg 67:147-158, 2009. 27. Jensen T, Jensen J, Norholt SE et al: Open reduction and rigid internal fixation of mandibular condylar fractures by an intraoral approach: a long-term follow-up study of 15 patients, J Oral Maxillofac Surg 64:17711779, 2006. 28. Walker RV: Condylar fractures: nonsurgical management, J Oral Maxillofac Surg 52:1185, 1994. 29. Villarreal PM, Monje F, Junquera LM, et al: Mandibular condyle fractures: determinants of treatment and outcome, J Oral Maxillofac Surg 62:155-163, 2004. 30. Zachariades N, Mezitis M, Mourouzis C et al: Fractures of the mandibular condyle: a review of 466 cases. Literature review, reflections on treatment and proposals, J Craniomaxillofac Surg 34:421-432, 2006.
38
Mandibular Subcondylar Fractures Larry L. Cunningham, Jr., Aaron Sterling Card
T
he most common site of all mandibular fractures is the condylar or subcondylar region, where 9% to 45% of mandibular fractures occur.1,2 The volume of debate about diagnosis and management of injuries to the temporomandibular joint (TMJ) sheds light on the difficulty associated with managing and repairing these complex injuries.3-5
ETIOPATHOGENESIS/CAUSATIVE FACTORS The etiology of subcondylar fractures mirrors that of most facial trauma. In adults, the most common causes of subcondylar fractures of the mandible are motor vehicle accidents, interpersonal violence,
work-related incidents, sporting accidents, and falls. In children, the most common causes are falls and bicycle accidents, although motor vehicle accidents also play an important role.1,2,6
PATHOLOGIC ANATOMY Subcondylar fractures of the mandible are defined as fractures below the level of the most inferior point on the sigmoid notch (Fig. 38-1).7 Depending on the circumstances, condylar neck fractures may be treated as subcondylar fractures; displacement and malocclusion in the setting of a long condylar neck (the ability to place at least two screws in the segment) would qualify. Historically, two systems have been developed for the classification of subcondylar fractures: the Lindahl system8-11 and the MacLennan system12
Mandibular Subcondylar Fractures
299
Mandibular condyle Neck of condyle
Fig. 38-1 n Lateral view of bones of the temporomandibular joint. (From Liebgott B: The anatomical basis of dentistry, ed 3, St. Louis, 2011, Mosby.)
BOX 38-1
The Lindahl System8-12
The Lindahl system classifies subcondylar fractures according to their anatomic location and the specific relationship between the fractured condyle and the glenoid fossa. The anatomic location of the fracture is described first. The most superior fracture is in the condylar head, which means that the fracture probably lies in the capsule of the temporomandibular joint; the second is a fracture in the thin neck of the condyle. The most inferior fracture lies in the subcondylar region below the anatomic neck and extends to the inferior portion of the ramus. Relationship of the condylar segment to the mandibular fragment: 1. Nondisplaced. 2. Deviated: angulation of the condylar head without dislocation of the fractured segments. 3. Displaced with medial or lateral overlap. The fractured condylar head lies either medial or lateral to the distal segment, with overlap. A medial position is more common because of the attachment and traction of the lateral pterygoid. Relationship between the condylar head and the glenoid fossa: 1. Nondisplaced. 2. Displaced: the condylar head remains in the fossa, but the joint space is altered. 3. Dislocation. The condylar head lies completely outside the anatomic fossa. This position requires rupture of the capsule.
(Boxes 38-1 and 38-2). The main objectives of these classifications systems are to describe the relationship of the condyle to the glenoid fossa and the relationship between the fractured proximal and distal segments. The condylar head can remain in the fossa, can be dis located out of the fossa either medially or laterally, or in rare cases can be dislocated into a fractured fossa. Fractured subcondylar segments can be nondisplaced (hairline fracture); alternatively, the proximal segment may be displaced either medially or laterally relative to the distal segment. Most of these fractures will be described as closed fractures unless they are associated with deep facial lacerations.
DIAGNOSTIC STUDIES Panoramic radiographs and Towne projection radiographs are effective methods of evaluating the subcondylar region of the mandible. However, computed tomography (CT) is currently the state of the
BOX 38-2
The MacLennan System12
Type I fracture, nondisplaced. Type II fracture, deviated. Angulation without overlap or separation. Greenstick fractures are included in this category. Type III fracture, displaced. This fracture displays overlap between the proximal and distal segments. Type IV fracture, dislocated. The condylar head leaves the capsule and lies outside the glenoid fossa. The location could be medial, lateral, anterior, or posterior.
art for detecting subcondylar fractures of the mandible. Threedimensional reconstructions of CT data offer the surgeon invaluable information about the position of the fractured segments, thereby allowing the most accurate planning of fracture management.13
TREATMENT/RECONSTRUCTIVE GOALS The goals of treating any type of trauma are to restore pain-free, premorbid form and function. With respect to subcondylar fractures of the mandible, the goal is restoration or maintenance of facial symmetry and posterior mandibular height. Treatment should be completed without injury to the parotid gland or the facial nerve and, preferably, without obvious scarring. Ideal restoration of function after treatment of a subcondylar fracture includes re-establishment of maximum mandibular movements: a maximum incisal opening (MIO) of 40 mm without deviation, lateral excursive movements of greater than 5 mm to the right and left, and the absence of signs or symptoms of temporomandibular disorder.
SPECIFIC TREATMENT AND TECHNIQUES SURGICAL ANATOMY TO CONSIDER The facial nerve exits the skull from the stylomastoid foramen and passes obliquely inferiorly and laterally until it enters the parotid gland. The common facial divisions of the nerve are the temporal, zygomatic, buccal, marginal mandibular, and cervical divisions. The branches most at risk during a transfacial approach to the subcondylar region are the buccal and marginal mandibular branches; those most at risk during an approach to the TMJ or an intracapsular fracture are the zygomatic and temporal branches.
300
Current Therapy in Oral and Maxillofacial Surgery
The confluence of the superficial temporal vein and the maxillary vein is called the retromandibular vein. This vascular structure can be the source of substantial bleeding deep to the ramus and the neck of the condyle because it descends just posterior to the ramus of the mandible through the parotid gland. This vein is lateral to the external carotid artery.
CLOSED MANAGEMENT Closed management3 is performed more than any other type of management because of its ease and long history of use. It is indicated for very specific subcondylar fractures, two of which are greenstick fractures in pediatric patients and nondisplaced fractures that do not “fall back”7 under anesthesia in adults. In addition, closed management is indicated for the treatment of any patient who refuses surgery as an option. The technique can be applied variably: as a liquid diet (as in the situation with greenstick fractures in pediatric patients), as maxillomandibular fixation (MMF) with arch bars and wires, or as fixation with arch bars and elastic bands. Likewise, elastic bands may be used either in a light, guiding fashion or in a heavy fashion, in which case they are very similar to wire fixation. Although closed management may still be commonplace, it cannot be considered the state of the art. It has even been shown that treatment by MMF may be associated with a higher incidence of temporomandibular dysfunction postoperatively than seen with other types of treatment and that closed treatment may not prevent further displacement of the fractured subcondylar segments.14,15 However, closed management can avoid the risks associated with general anesthesia, facial nerve injury, parotid injury, and scarring and can also shorten the duration of soft tissue swelling after the injury.
OPEN REDUCTION WITH INTERNAL FIXATION Indications Zide and Kent presented the absolute and relative indications for open reduction of mandibular condylar fractures (Box 38-3).16 Since their presentation of the clinical standard, many improvements have
BOX 38-3
Zide and Kent’s Indications for Open Reduction of Condylar Fractures16
Absolute indications (pertain to children as well as to adults): 1. Displacement into the middle cranial fossa 2. Impossibility of obtaining adequate occlusion by closed reduction 3. Lateral extracapsular displacement of the condyle 4. Invasion by a foreign body (e.g., gunshot wound) Relative indications: 1. Bilateral condylar fractures in an edentulous patient when a splint is unavailable or splinting is impossible because of atrophy of the alveolar ridge 2. Unilateral or bilateral condylar fractures for which splinting is not recommended for medical reasons or when adequate physiotherapy is impossible 3. Bilateral condylar fractures associated with comminuted midfacial fractures 4. Bilateral condylar fractures and associated gnathologic problems such as retrognathia or prognathism, open bite with periodontal problems or lack of posterior support, loss of multiple teeth and later need for elaborate reconstruction, bilateral fractures and unstable occlusion because of orthodontics, and unilateral condylar fracture with an unstable fracture base
been made in rigid internal fixation and endoscopic application to craniofacial fractures, and these improvements have allowed expanded indications for open reduction and internal fixation (ORIF) of subcondylar fractures.10 More recent studies have focused on the complications associated with open and closed treatment of subcondylar fractures of the mandible (Box 38-4).3,4,14,15,17-20 The international principles guiding fracture management today include anatomic reduction of fractured segments, functionally stable internal fixation, and early mobilization; these principles have been well established in the dental literature.21,22 The goal of fracture management is normal, pain-free function. As all surgeons know, the decision whether to operate is not always as clear as the guiding principles would suggest. Surgeons should discuss the following important points with the patient when deciding whether to open a subcondylar fracture: the severity of the fracture, the amount of disability that is likely to occur, the relative risks to important
BOX 38-4
Considerations for Approach to Subcondylar Fractures
In 2004, Edward Ellis III, DDS, gave a presentation at the Symposium on Management of Subcondylar Fractures; Historical Perspectives and New Horizons. He addressed the historical aspects of subcondylar fracture management and readdressed his indications for open surgical management in light of advancing techniques for stable internal fixation. He acknowledged the lack of universal agreement among surgeons with regard to management protocols, yet stated that most fractures may be managed satisfactorily with closed techniques. He summarized his indications for open treatment: 1. Displacement of the condyle into the middle cranial fossa (with or without fracture) 2. Lateral extracapsular displacement of the condyle (with or without fracture) 3. Impossibility of obtaining proper occlusion with closed techniques 4. Condylar fractures associated with comminuted fractures at or above Le Fort I In addition, Ellis discussed the relative indications for open and closed management. He stated that surgeons, at their own discretion, may use either the open or closed method, depending on their own philosophy and experience. Factors to be considered when deciding between open and closed management include 1. Loss of ramus height beyond acceptable esthetic limits or loss of the posterior dentition that would ordinarily assist in maintaining height of the ramus 2. The skeletal age of the patient (Children’s jaws can adapt to a new condylar position, or frank neocondylar synthesis may occur.) 3. Ability to attain stable fixation (If a fracture is located high on the condylar neck or in the capsule, nonsurgical management may be more appropriate. Some patients’ medical condition may not be considered stable enough to allow them to undergo either open or closed management, or they may have a strong desire to avoid intermaxillary fixation and would therefore chose an alternative management method.) 4. Associated fractures, including bilateral condylar fractures, especially those that are displaced (Opening at least one fracture may improve occlusal outcomes.) 5. State of the patient’s dentition (When dentition is incomplete, it may be impossible to maintain the position of the mandible when a new articulation is established. Open treatment may be the better option for preventing posterior vertical collapse or the need for additional splint fabrication to maintain stability.)
Mandibular Subcondylar Fractures anatomic structures, the likelihood of scarring, and the patient’s preferences. The patient should be made aware of the potential complications associated with subcondylar fractures, including changes in occlusion, pain and temporomandibular dysfunction, and possible alterations in the symmetry of the face.4,7,15,18 Transfacial approaches to the subcondylar region are favored because they allow direct access and visualization, thereby increasing the surgeon’s ability to achieve anatomic reduction of the fracture. Surgical complications that are associated with open treatment of condylar process fractures and that lead to permanent dysfunction or deformity are generally uncommon.17 However, some of these risks, such as facial nerve injury, sialocele, infection, and scarring, though uncommon, are serious and may be difficult to manage. Still, all of these approaches can be technically challenging, and learning curves should be expected. The most popular approaches are the submandibular approach and the retromandibular approach.23 The senior author prefers the retromandibular approach for its proximity to the fracture site (Fig. 38-2). The indications for endoscopically assisted ORIF of subcon dylar fractures are the same as those for the open transfacial approaches. However, because the potential difficulty of the endoscopically assisted approach is considerably increased when comminuted fractures are present, its use may be contraindicated in such cases.8
B
A
D
301
The intraoral approach without the benefit of an endoscope was first reported by Jeter and co-authors. This approach reduced the risk for facial nerve damage and avoided the large facial scars associated with transfacial approaches; it also allowed the surgeon to accurately reduce and fixate the fracture while maintaining the patient’s proper occlusion.24 However, the difficulty associated with applying this technique without the advantage of an endoscope limited the number of patients who were able to benefit from open reduction of the condyle. The advantages of the endoscope have been described more recently and have furthered the argument for the endoscopic approach with intraoral access, an approach associated with minimal complications.8,25 The technique has a steep learning curve, but the time required for applying this technique decreases after sufficient experience has been gained. Careful patient selection is essential.13,26,27 The endoscopically assisted approach can allow restoration of the relationship between the condyle and the mandible and can re-establish function to a state that is as close as possible to the preinjury condition with minimal risk for facial nerve damage or facial scarring (Fig. 38-3).
Contraindications High condylar neck fractures (i.e., those that leave a segment that is too short to accept two screws) and condylar head fractures should not be treated with ORIF. Displaced subcondylar fractures with
C
E Fig. 38-2 n Extraoral approach to a mandibular subcondylar fracture via a retromandibular incision. A, Patient markings. B, Visualization of the fracture. The superior retractor allows visualization of the distal fractured stump of the proximal segment. C, Fixation plate in place after fracture reduction. D, Six weeks postoperatively with a maximum incisal opening of 40 mm. E, Postoperative panoramic radiograph.
302
Current Therapy in Oral and Maxillofacial Surgery
A
B
C
D
E
F Fig. 38-3 n Endoscopically assisted approach to a mandibular subcondylar fracture. A, Preoperative panoramic radiograph. B, Preoperative Towne view showing significant lateral over-ride of the left subcondylar fracture. C, Endoscopic view of the distal fractured stump of the proximal segment. D, Endoscopic view of fixation placement. E, Postoperative panoramic radiograph. F, Postoperative maximum incisal opening of 50 mm to the maxillary edentulous ridge.
medial override of the proximal segment are the most difficult to reduce adequately with an endoscopically assisted approach. A surgical procedure is justified only when the condylar segments are displaced. Fractures that are unlikely to affect occlusion or facial height (greenstick fractures or medial pole fractures) should not be opened.7
POSTOPERATIVE CARE Postoperative care after repair of subcondylar fractures should consist of the placement of light elastic bands for occlusal guidance; these bands should remain in place for 7 to 14 days. Generally, a full liquid diet is recommended for 3 days after surgery, followed
Mandibular Subcondylar Fractures
303
by a soft mechanical diet for the next 3 to 4 weeks. Early mobilization of the joint is important so that ankylosis can be avoided. After an initial healing period of 2 weeks, patients are encouraged to begin their own physical therapy to increase MIO to the postoperative goal of 40 mm. Available commercial devices can assist in this rehabilitation; however, stacked tongue blades offer the patients an inexpensive and effective guide. Patients are encouraged to use tongue blades to assist in their rehabilitation four to five times during the day for a total of 30 minutes of stretching per day. In addition, they are asked to attempt to add one tongue blade to the stack every day or two until they achieve an MIO of 40 mm.
condyle to remodel allow greater success of nonsurgical therapy in children than in adults. The general consensus is that nonsurgical management is the best option for children until they reach the age of 12 years, until there is a departure from mixed dentition, or until puberty begins.3,8,16 Conservative treatment may consist of a liquid diet only or a brief period of MMF (1 to 2 weeks) with arch bars and heavy elastic bands. Following this short period of inactivity, active function and joint physiotherapy are important to reduce the formation of scar tissue and prevent TMJ fibrosis or ankylosis.6
MANAGEMENT CONTROVERSY
The authors would like to thank Flo Witte for her expert editorial assistance.
Mobilization and rehabilitation are the keys in treating subcondylar fractures.28 Management of subcondylar fractures is controversial because many of these fractures will heal with acceptable results after being treated by MMF. Avoidance of surgery certainly alleviates the risk for surgical complications. In addition, using shorter periods of MMF, 3 to 4 weeks rather than 6 weeks, creates less of a burden for the patient. Although MMF is faster and less expensive than ORIF,29 it does not eliminate all complications and indeed may result in malocclusion, which requires a secondary surgical procedure, most often sagittal split osteotomy. Other potential complications associated with MMF are TMJ dysfunction, malo cclusion, and altered facial symmetry.4,14,15,18 Although rigid internal fixation does not eliminate the importance of rehabilitation for increasing the patient’s MIO, it is certainly associated with shorter convalescence, particularly for more difficult, severely displaced and dislocated fractures that cause substantial disturbances in occlusion, loss of ramal height, and facial asymmetry, as well as for multiple facial fractures. ORIF may also be the treatment of choice when MMF is not recommended, such as for patients with certain co-morbid conditions (learning disabilities, pulmonary diseases, seizure disorders).18,30 Ideally, surgeons would be adequately trained to provide alternative methods of care. When offered the option of surgery and rehabilitation or the option of any period of MMF, many patients choose the surgical procedure despite its potential risks.
FRACTURES IN CHILDREN Subcondylar fractures in children are different from those in adults for a number of reasons. The presence of primary or mixed dentition, remaining growth potential, and the great capacity for the childhood
ACKNOWLEDGMENT
PEARLS AND PITFALLS • When subcondylar fractures are treated with MMF, close follow-up and rehabilitation are very important. • Minor occlusal discrepancies after treatment can be treated with elastic bands or orthodontics and with vigilance in aiding the patient to achieve an MIO of 40 mm. • Treating a patient with MMF when there is substantial overlap of the fractured segments or rotating the condylar segment during pretreatment imaging may be associated with a risk for malocclusion after treatment. • When multiple fractures of the mandible are treated with ORIF of the subcondylar fracture, the mandible should be reduced and fixated in an anterior to posterior direction; the most anterior fracture should be plated first. • MMF should not be in place when the subcondylar segment is reduced. • MMF can be used before screw placement if the segments remain reduced. • Endoscopic approaches are technique-sensitive, and the surgical instruments are unique. • Surgeons should select early cases carefully so that they can familiarize themselves with the techniques. • Fractures with lateral override are much easier to treat with endoscopic guidance, whereas medially displaced segments are more difficult to treat with this technique. • The retromandibular approach to the subcondylar region is associated with a high risk for encountering the facial nerve. • Blunt dissection through the parotid is mandatory, and the assistance of a nerve stimulator is recommended.
REFERENCES 1. Ellis E 3rd, Moos KF, el-Attar A: Ten years of mandibular fractures: an analysis of 2,137 cases, Oral Surg Oral Med Oral Pathol 59:120-129, 1985. 2. Haug RH, Prather J, Indresano AT: An epidemiologic survey of facial fractures and concomitant injuries, J Oral Maxillofac Surg 48:926-932, 1990. 3. Ellis E, Throckmorton GS: Treatment of mandibular condylar process fractures: biological considerations, J Oral Maxillofac Surg 63:115-134, 2005. 4. Ellis E 3rd, Simon P, Throckmorton GS: Occlusal results after open or closed treatment of fractures of the mandibular condylar
process, J Oral Maxillofac Surg 58:260-268, 2000. 5. Nussbaum ML, Laskin DM, Best AM: Closed versus open reduction of mandibular condylar fractures in adults: a meta-analysis, J Oral Maxillofac Surg 66:1087-1092, 2008. 6. Miller RI, McDonald DK: Remodeling of bilateral condylar fractures in a child, J Oral Maxillofac Surg 44:1008-1010, 1986. 7. Ellis E 3rd: Method to determine when open treatment of condylar process fractures is not necessary, J Oral Maxillofac Surg 67:16851690, 2009. 8. Lindahl L, Hollender L: Condylar fractures of the mandible. II. A radiographic study of
remodeling processes in the temporomandibular joint, Int J Oral Surg 6:153-165, 1977. 9. Lindahl L: Condylar fractures of the mandible. IV. Function of the masticatory system, Int J Oral Surg 6:195-203, 1977. 10. Lindahl L: Condylar fractures of the mandible. III. Positional changes of the chin, Int J Oral Surg 6:166-172, 1977. 11. 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 6:1221, 1977.
304
Current Therapy in Oral and Maxillofacial Surgery
12. MacLennan W: Consideration of 180 cases of typical fractures of the mandibular condylar process, Br J Plast Surg 5:122-128, 1952. 13. Kellman RM, Cienfuegos R: Endoscopic approaches to subcondylar fractures of the mandible, Facial Plast Surg 25:23-28, 2009. 14. Ellis E 3rd, Palmieri C, Throckmorton G: Further displacement of condylar process fractures after closed treatment, J Oral Maxillofac Surg 57:1307-1316, discussion 1316-1317, 1999. 15. Haug RH, Assael LA: Outcomes of open versus closed treatment of mandibular subcondylar fractures, J Oral Maxillofac Surg 59:370-375, discussion 375-376, 2001. 16. Zide MF, Kent JN: Indications for open reduction of mandibular condyle fractures, J Oral Maxillofac Surg 41:89-98, 1983. 17. Ellis E 3rd, McFadden D, Simon P, et al: Surgical complications with open treatment of mandibular condylar process fractures, J Oral Maxillofac Surg 58:950-958, 2000. 18. Ellis E 3rd, Throckmorton G: Facial symmetry after closed and open treatment of fractures of the mandibular condylar process, J Oral Maxillofac Surg 58:719-728, discussion 729-730, 2000.
19. Ellis E 3rd, Throckmorton GS: Bite forces after open or closed treatment of mandibular condylar process fractures, J Oral Maxillofac Surg 59:389-395, 2001. 20. Ellis E 3rd, Throckmorton GS, Palmieri C: Open treatment of condylar process fractures: assessment of adequacy of repositioning and maintenance of stability, J Oral Maxillofac Surg 58:27-35, discussion 35, 2000. 21. Greenberg AM, editor: Craniomaxillofacial fractures: principles of internal fixation using the AO/ASIF technique. New York, 1993, Springer-Verlag. 22. Prein J, editor: Manual of internal fixation in the cranio-facial skeleton: techniques recommended by the AO/ASIF maxillofacial group. New York, 1998, Springer-Verlag. 23. Chossegros C, Cheynet F, Blanc JL, et al: Short retromandibular approach of subcondylar fractures: clinical and radiologic long-term evaluation, Oral Surg Oral Med Oral Pathol Oral Radiol Endod 82:248-252, 1996. 24. Jeter TS, Van Sickels JE, Nishioka GJ: Intraoral open reduction with rigid internal fixation of mandibular subcondylar fractures, J Oral Maxillofac Surg 46:1113-1116, 1988.
25. Kellman RM: Endoscopically assisted repair of subcondylar fractures of the mandible: an evolving technique, Arch Facial Plast Surg 5:244-250, 2003. 26. Schmelzeisen R, Cienfuegos-Monroy R, Schon R et al: Patient benefit from endoscopically assisted fixation of condylar neck fractures—a randomized controlled trial, J Oral Maxillofac Surg 67:147-158, 2009. 27. Jensen T, Jensen J, Norholt SE et al: Open reduction and rigid internal fixation of mandibular condylar fractures by an intraoral approach: a long-term follow-up study of 15 patients, J Oral Maxillofac Surg 64:17711779, 2006. 28. Walker RV: Condylar fractures: nonsurgical management, J Oral Maxillofac Surg 52:1185, 1994. 29. Villarreal PM, Monje F, Junquera LM, et al: Mandibular condyle fractures: determinants of treatment and outcome, J Oral Maxillofac Surg 62:155-163, 2004. 30. Zachariades N, Mezitis M, Mourouzis C et al: Fractures of the mandibular condyle: a review of 466 cases. Literature review, reflections on treatment and proposals, J Craniomaxillofac Surg 34:421-432, 2006.