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Symphysis Fractures of the Mandible: How Much Fixation Is Enough?
CRANIOMAXILLOFACIAL TRAUMA
Open Reduction and Internal Fixation of Combined Angle and Body/Symphysis Fractures of the Mandible: How Much Fixation Is Enough? Edward Ellis III, DDS, MS* Purpose: To assess the internal fixation requirements for combined mandibular angle and contralateral body or symphysis fractures of the mandible. Patients and Methods:
Two sample groups of patients treated for combined angle and body/symphysis fractures were compared for the development of major complications, defined as a need for another surgical intervention. The groups were divided based on whether they were treated with rigid or nonrigid fixation of the body or symphysis fracture.
Results: Nine hundred seventy-six patients were treated in the rigid group, and 149 were treated in the nonrigid group. There was a 4.9% major complication rate in those in the rigid fixation group versus 15.4% in the nonrigid fixation group (P < .001). Conclusion:
The fixation requirements of patients treated with double fractures of the mandible are different than when treating isolated fractures of the mandible. Double fractures require that at least one of the fractures undergoes rigid fixation to decrease the incidence of complications. Ó 2013 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 71:726-733, 2013 purpose of this study is to examine a large sample of patients treated with rigid or nonrigid fixation for this common mandibular fracture.
Over the past 30 years, the management of mandibular fractures has changed from intermaxillary fixation (IMF) with or without internal wire fixation to internal plate and/or screw fixation and no IMF. While the use of plate and/or screw fixation has potential benefits for the patient, complications are not uncommon.1-6 The most common mandibular fracture pattern seen in most major medical centers in the United States is the combination of an angle fracture (usually the left side)3-7 combined with a contralateral fracture of the mandibular body or symphysis. Although studies have been published that have evaluated internal fixation schemes for isolated fractures of the angle6,8 or body/symphysis,9-11 no studies have specifically evaluated the fixation requirements for the mandible that has fractures through both the angle and the contralateral body or symphysis. The
Patients and Methods All dentate patients treated for combined fractures of the mandibular angle and contralateral body or symphysis from July 1, 1993 through December 31, 2012 were included in this study. Inclusion criteria were 1) simple (linear) fractures through the angle and the contralateral body or symphysis; 2) neither fracture was grossly infected at time of treatment; 3) open reduction and internal fixation (ORIF) of the angle fracture through intraoral approach and application of a single 2 mm miniplate (1 mm thick) along the superior border (Champy technique);12 4) ORIF of contralateral body or symphysis fracture through a transoral approach using a variety of plate and/or screw techniques; 5) no postoperative IMF, 6) age > 15 years; and 7) 6-12 weeks of follow-up. Exclusion criteria were 1) comminution of either fracture; 2) gross infection of either fracture; and 3) insufficient records and/ or follow-up. A large number of residents were involved in the surgeries, but faculty was always scrubbed. The Internal Review Board determined that their review of this project was unnecessary
*Professor and Chair, Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center, San Antonio, TX. Address correspondence and reprint requests to Dr Ellis: Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center, 7703 Floyd Curl Drive, MC7908, San Antonio, TX 78229-3900; e-mail: [email protected] Ó 2013 American Association of Oral and Maxillofacial Surgeons 0278-2391/12/7008-0$36.00/0 http://dx.doi.org/10.1016/j.joms.2012.09.017
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FIGURE 1. Examples of rigid fixation applied to the mandibular body/symphysis fractures. A, 2 lag screws. B, 2.4-mm dynamic compression plate. C, two 2-mm miniplates (1 mm thick). (Fig 1 continued on next page.) Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
because of the removal of patient identifiers. The surgical technique for the treatment of the fractures has been described in other publications.3,6,9 In addition to demographic information (ie, gender, age, cause, etc), the following data on all cases were prospectively collected: 1) location of angle fractures (ie, left versus right); 2) site of body or symphysis fracture; 3) presence of a tooth in the line of the fractures; 4) extraction of tooth in line of fracture; 5) internal fixation techniques for the
body or symphysis fracture; 6) occlusal relationship at last follow-up visit; and 7) major postsurgical complications, which were defined as a need for further surgical intervention. Simple wound care delivered in the clinical setting, including prescription of antibiotics for minor wound infection and use of elastics for slight malocclusion, was not considered a major complication. The sample was divided into 2 groups based on the fixation schemes used for the body or symphysis
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FIGURE 1 (Cont’d.) D, 2-mm locking plate (much thicker and stronger than standard 1-mm-thick miniplates). E, 2-mm locking plate with a smaller, thinner miniplate placed above it. F, 2.4-mm reconstruction bone plate. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
fractures. The rigid group was defined as having one of the following fixation schemes used on the body or symphysis fracture: 1) at least two 2.4-mm lag screws with an arch bar (Fig 1A); 2) one 2.4-mm compression plate with an arch bar (Fig 1B); 3) two 2-mm noncompression locking or nonlocking miniplates (1 mm thick) with an arch bar (Fig 1C); 4) one 2-mm locking mandibular bone plate (Fig 1D) (Synthes 447.103; 447.014; 447.105; 447.106, Paoli, PA) (all are thicker and much stronger than standard 1-mm-thick miniplates) with or without a second plate (Fig 1E) and an arch bar; and 5) a nonlocking 2.7-mm or locking 2.4-mm reconstruction bone plate with or without an arch bar (Fig 1F). The nonrigid group was defined
as having a single 2-mm noncompression locking or nonlocking miniplate (1 mm thick) placed across the body or symphysis fracture with an arch bar (Fig 2). The 2 groups were compared for differences in demographic characteristics using c2 cross-table analysis for discontinuous variables or Student t test for continuous variables. Outcomes for the 2 groups were similarly analyzed.
Results A total of 976 patients were included in the rigid group. They ranged in age from 15 to 59, with a mean of 29.2 years. There was an overwhelming
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FIGURE 2. Radiograph showing a single 2-mm miniplate (1-mm thick) applied to both fractures. This is an example of nonrigid fixation. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
predominance of males (n = 893) and left-sided angle fractures (n = 644). Altercations were the predominant cause (n = 879), followed by motor vehicle accidents (n = 49), falls (n = 34), and others (n = 14). Treatment of the body or symphysis fractures in the rigid sample included 1) lag screws (n = 141); 2) compression plate (n = 95); 3) 2 miniplates (n = 379); 4) 2-mm locking mandibular plate (n = 306); and 5) reconstruction bone plate (n = 55). A total of 149 patients were included in the nonrigid group. They ranged in age from 16 to 54, with a mean age of 28.4 years. There were 134 males, and the left angle was involved 101 times. Altercations were involved in 129 cases, motor vehicle accidents in 8, falls in 8, and other causes in 4. There was no significant difference in the demographic characteristics of the 2 groups. In the rigid group there were 48 major complications (4.9%) requiring surgical intervention. There were no cases of malocclusion requiring secondary intervention. Twelve complications were at the site of the body fracture. All others were located at the site of the angle fracture. Eight of the complications located at the body/symphysis fracture site were wound problems with dehiscence of the incision and exposure of the bone plate; in four other cases, there was associated infection. These all required surgery to remove the bone plates and to treat any infection present. The remaining 36 complications all presented as wound problems at the site of the angle fracture. Nineteen presented as infections with either abscess formation (n = 7) or drainage of purulent material intraorally (n = 8) or extraorally (n = 4). All 19 patients underwent incision and drainage through an intraoral (n = 13) or extraoral approach (n = 6) and either immediate or subsequent hardware removal in 15 patients. In 5 patients, there was no bony union at the time of plate
removal and a period of IMF was used. One of these did not unite and required bone grafting 4 months later. The remaining 17 patients presented with noninfected wound problems. Typically, they had granulation tissue around the incision site (Fig 3), plate and/ or bone exposure, and (in 7 cases) loose hardware. All of these patients required surgery to remove the bone plate and debride any nonvital bone. In only 4 patients was the fracture not united at the time of plate removal. In these patients, a period of IMF was used. In the nonrigid group, there were 23 major complications (15.4%), of which 22 were postoperative wound problems. Fourteen presented as a noninfected wound problem with granulation tissue, plate and/or bone exposure, and (in 9 cases) loose hardware. The wound problem occurred at the angle fracture site in 8 cases, at the body fracture site in 2 cases, and at both sites in 4 cases. Removal of hardware and
FIGURE 3. Typical appearance of wound problem characterized by granulation tissue, dehiscence, and/or exposed bone and hardware. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
730 nonvital bone was performed through transoral approaches from 4 weeks to 8 weeks after fracture treatment. The fractures had healed in 8 of the cases, but 6 had mobility at the time of hardware removal and were placed into IMF for a period of time. All eventually went on to osseous union. Eight cases had frank infection, 7 at the angle fracture site and 1 at the body fracture site. The infections presented with abscess formation without spontaneous drainage in 4 cases and intraoral purulent drainage through the incision site in the others. All infections required intraoral incision and drainage, and 7 required hardware removal (4 at the time of incision and drainage at between 4 and 7 weeks, and 3 at 8 weeks). At the time of hardware removal, 3 had mobility and required a period of IMF to obtain union. There was only one case of malocclusion requiring secondary intervention. This complication was noted 4 weeks postoperatively. The radiograph reported that the plate on the body fracture had undergone slight in-line deformation and a small step between the teeth on each side of the fracture developed, resulting in the malocclusion (Fig 4). In this case, there was a tooth in the fracture line that was removed at the time of treating the body fracture. This case required surgery to remove the plate, reestablish the proper occlusion, and provide stable internal fixation. There was a statistically significant difference in the major complication rate between the rigid and nonrigid groups (P < .001).
Discussion Bilateral fractures occur in over half of the patients who present with mandibular fractures.3,4,7,13-17 The most common mandibular fracture seen in most
FRACTURES: HOW MUCH FIXATION IS ENOUGH?
medical centers in developed nations is an angle fracture combined with a contralateral fracture of the mandibular body or symphysis.3,4,7,16-18 The reason for this is that most of them are caused by interpersonal violence with a blow to the side of the face.3-8,16,17 In spite of their prevalence, the specific fixation requirements for combined angle and contralateral body/symphysis fractures has not been addressed to any extent in the literature. In fact, fixation requirements for bilateral mandibular fractures are not even mentioned in either of the AO/ ASIF’s Manual of Internal Fixation of the CranioFacial Skeleton.19,20 One might question whether the fixation requirements for a combined angle/body or angle/symphysis fracture is the same as what one might use for an isolated angle or an isolated body or symphysis fracture. The results of this study show that the fixation requirements for a bilateral fracture can be different from what is required for an isolated (single) fracture to achieve sufficient stability during the healing period. To better understand the fixation requirements of these fractures, some definitions are helpful. Rigid internal fixation is a term applied to the application of sufficient internal hardware to prevent movement across the fracture site when normal functional forces are in effect. Examples of rigid internal fixation include locking/nonlocking reconstruction bone plates, multiple bone plates at the fracture site, single strong nonreconstruction bone plates, or multiple lag screws. All are of sufficient strength to prevent interfragmentary motion during function and allow primary osseous union to proceed. Anything less than rigid is, by definition, nonrigid. Nonrigid fixation spans a continuum from almostcompletely rigid to completely mobile (eg, intraosseous
FIGURE 4. Radiograph showing in-line deformation of the bone late applied to the body/symphysis region of the mandible, with resulting malocclusion. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
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FIGURE 5. Demonstration of the biomechanics of combined angle and contralateral condylar process fractures. A, Mandibular model showing a single miniplate applied to the left angle fracture and the right condylar process fracture that has not been treated. B, Model is being loaded on the right posterior mandible. Note the torsion that occurs at the inferior border of the mandible at the angle fracture. The miniplate is not capable of preventing this because it is not strong enough. C, Illustration showing that a single miniplate cannot prevent the tendency for widening of the mandible. D, Mandibular model being similarly loaded as in 5B but with rigid fixation (2 miniplates) applied to the angle fracture. This fixation is able to prevent torsional separation at the inferior border at the angle fracture. E, Illustration showing stable fixation has been applied to the right condylar process and nonrigid (single miniplate) fixation has been applied to the left angle fracture. Because of the continuity and stability across the right temporomandibular joint by the bone plate in the subcondylar region, the nonrigid fixation of the angle fracture becomes functionally stable, and the patient does not need postoperative IMF. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
wire). Nonrigid fixation can, however, become functionally stable fixation. Functionally stable fixation is not rigid fixation but is the application of various hardware schemes which do not prevent micro-motion across the fracture site during function, but permit healing of the fracture by secondary bone healing (with formation of callous) and without IMF. Examples of nonrigid fixation that are functionally stable are the use of a single titanium miniplate for a fracture of the angle of the mandible (Champy technique)12or a single titanium miniplate for a fracture of the body
or symphysis of the mandible. The original Champy technique used stainless steel miniplates that were 1 mm thick. For fractures of the mandible, the fixation provided by these plates might be considered ‘‘rigid fixation,’’ because they were much stronger than the 1-mm-thick titanium miniplates currently available from most manufacturers. Therefore, one must consider this when using the fixation recommendations of Champy’s original work with the plates we currently have available. It has been reported in many studies that when treating mandibular fractures, rigid fixation is not
732 always necessary, and there are multiple functionally stable hardware constructs that result in healing and excellent postoperative results.4,5,8,21-24 The results of this study show a significantly higher rate of wound problems when both fractures are treated with nonrigid fixation. This indicates that although nonrigid forms of fixation may work on isolated (single) fractures of the mandible, they might not be reliable when used on more than one fracture of the mandible. This should not be surprising when one considers the difference in the biomechanics of mandibular function with single versus double fractures. The easiest way to understand the differences in biomechanics might be to consider an angle fracture combined with a contralateral condylar process fracture (Fig 5A). The bone fragment between the 2 fractures becomes a free-floating fragment that can be readily displaced by functional loads. If one chooses to treat the condylar fracture closed, the forces acting across the fracture of the angle become more complex than with an isolated fracture of the angle, with a torque moment of the fragment between the 2 fractures. Because of the length of the fragment (from the angle to the contralateral condylar process), the torque moment arm is long, and the force is large. If the angle fracture is treated with a single titanium miniplate at the superior border according to Champy,12 torquing of the fragments at the inferior border can occur with mandibular function and occlusal loading on the side of the condylar process fracture (Fig 5B). Additionally, with loss of the craniomandibular articulation on the left side, there is little resistance to widening of the mandible from the titanium miniplate applied to the angle fracture, and a gap can form on the lingual cortex (Fig 5C). The fixation applied to the angle, therefore, must be stronger than fixation required for an angle fracture in isolation. Based on the results of this study, rigid internal fixation should be applied to the angle fracture if the condyle fracture is to be treated closed. In this scenario, a stronger bone plate or 2 miniplates could be applied to rigidly stabilize the angle fracture and prevent separation of the fragments at the inferior border (Fig 5D). On the other hand, if the condylar fracture were to be made stable by open reduction and internal fixation, one could essentially turn a bilateral fracture into an isolated angle fracture, allowing less fixation (ie, single miniplate) to be applied to provide a functionally stable result (Fig 5E). What fixation should be applied to a combined angle plus contralateral body or symphysis fracture? Because the second fracture changes the biomechanics acting across the fractures, it is possible that single
FRACTURES: HOW MUCH FIXATION IS ENOUGH?
titanium miniplates applied to both fractures cannot counter the more complex forces working on the dento-osseous fragment between the 2 fractures, and there can be a tendency for the fracture fragments to separate or twist under function (Fig 6A). On the basis of the results of this study, the most predictable fixation scheme is to treat at least one of the fractures with rigid internal fixation, and to treat the other with nonrigid fixation. By doing so, a bilateral (double) fracture of the mandible is converted to a unilateral (single) fracture, for which the biomechanics are less complex. The entire construct then becomes functionally stable. In practice, it is easier to perform rigid fixation of the more anterior fracture, and so
FIGURE 6. Illustrations demonstrating the potential problem of treating combined angle and contralateral body or symphysis fractures with nonrigid fixation. A, The intervening segment of the mandible between the 2 fractures can undergo torquing from occlusal and muscular forces acting on it, allowing separation of the fractured fragments from one another. B, The application of rigid fixation of the body/symphysis fracture (in this case by a larger, stronger plate) allows the nonrigid fixation at the angle fracture (by a miniplate) to become functionally stable, obviating the need for postoperative IMF. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
EDWARD ELLIS III
the symphysis or body fracture is treated with 2 lag screws, 2 miniplates, or a stronger bone plate combined with an arch bar, and the angle fracture is then treated with a single miniplate (Fig 6B). Summarizing, fixation that may have been functionally stable on a fracture in isolation may become unstable in a mandible with more than one fracture. Because the second fracture changes the biomechanics acting across the fractures, it seems prudent to apply hardware with increased rigidity and strength on at least one of the fractures when treating bilateral fractures of the mandible.
References 1. Ellis E 3rd, Sinn DP: Treatment of mandibular angle fractures using two 2.4 mm dynamic compression plates. J Oral Maxillofac Surg 51:969, 1993 2. Ellis E 3rd, Karas N: Treatment of mandibular angle fractures using two mini dynamic compression plates. J Oral Maxillofac Surg 50:958, 1992 3. Ellis E 3rd, Walker L: Treatment of mandibular angle fractures using two noncompression miniplates. J Oral Maxillofac Surg 52:1032, 1994 4. Ellis E 3rd, Walker LR: Treatment of mandibular angle fractures using one noncompression miniplate. J Oral Maxillofac Surg 54:864, 1996 5. Feller KU, Schneider M, Hlawitschka M, et al: Analysis of complications in fractures of the mandibular angle—A study with finite element computation and evaluation of data of 277 patients. J Craniomaxillofac Surg 31:290, 2008 6. Ellis E 3rd: A prospective study of 3 treatment methods for isolated fractures of the mandibular angle. J Oral Maxillofac Surg 68:2743, 2010 7. Paza AO, Abuabara A, Passeri LA: Analysis of 115 mandibular angle fractures. J Oral Maxillofac Surg 66:73, 2008 8. Barry CP, Kearns GJ: Superior border plating technique in the management of isolated mandibular angle fractures: A retrospective study. J Oral Maxillofac Surg 65:1544, 2007
733 9. Ellis E 3rd, Ghali GE: Lag screw fixation of mandibular angle fractures. J Oral Maxillofac Surg 49:234, 1991 10. Ellis E 3rd: A study of 2 bone plating methods for fractures of the mandibular symphysis/body. J Oral Maxillofac Surg 69:1978, 2011 11. Ellis E 3rd: Is lag screw fixation superior to plate fixation to treat fractures of the mandibular symphysis? J Oral Maxillofac Surg 70:875, 2012 12. Champy M, Lodde JP, Schmitt R, et al: Mandibular osteosynthesis by miniature screwed plates via a buccal approach. J Maxillofacial Surg 6:14, 1978 13. James RB, Fredrickson C, Kent JN: Prospective study of mandibular fractures. J Oral Surg 39:275, 1981 14. Chuong R, Donoff RB, Guralnick WC: A retrospective analysis of 327 mandibular fractures. J Oral Maxillofac Surg 41:305, 1983 15. 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, 1985 16. Fox AJ, Kellman RM: Mandibular angle fractures: Two-miniplate fixation and complications. Arch Facial Plast Reconstr Surg 5: 464, 2003 17. Guimond C, Johnson JV, Marchena JM: Fixation of mandibular angle fractures with a 2.0-mm 3-dimensional curved angle strut plate. J Oral Maxillofac Surg 63:209, 2005 18. Lamphier J, Ziccardi V, Ruvo A, Janel M: Complications of mandibular fractures in an urban teaching center. J Oral Maxillofac Surg 61:745, 2003 19. Prein J (ed): Manual of Internal Fixation in the Cranio-Facial Skeleton: Techniques Recommended by the AO/ASIF Maxillofacial Group. Berlin, Germany: Springer, 1998 20. Ehrenfeld M, Manson PN, Prein J (eds): Principles of Internal Fixation of the Craniomaxillofacial Skeleton. Trauma and Orthognathic Surgery. Stuttgart, Germany: George Thieme Verlag, 2012 21. Cawood JI: Small plate osteosynthesis of mandibular fractures. Br J Oral Maxillofac Surg 23:77, 1985 22. Kroon FH, Mathisson M, Cordey JR, Rahn BA: The use of miniplates in mandibular fractures. An in vitro study. J Craniomaxillofac Surg 19:199, 1991 23. Tate GS, Ellis E 3rd, Throckmorton G: Bite forces in patients treated for mandibular angle fractures: Implications for fixation recommendations. J Oral Maxillofac Surg 52:734, 1994 24. Potter J, Ellis E 3rd: Treatment of mandibular angle fractures with a malleable noncompression miniplate. J Oral Maxillofac Surg 57:288, 1999
Open Reduction and Internal Fixation of Combined Angle and Body/Symphysis Fractures of the Mandible: How Much Fixation Is Enough? Edward Ellis III, DDS, MS* Purpose: To assess the internal fixation requirements for combined mandibular angle and contralateral body or symphysis fractures of the mandible. Patients and Methods:
Two sample groups of patients treated for combined angle and body/symphysis fractures were compared for the development of major complications, defined as a need for another surgical intervention. The groups were divided based on whether they were treated with rigid or nonrigid fixation of the body or symphysis fracture.
Results: Nine hundred seventy-six patients were treated in the rigid group, and 149 were treated in the nonrigid group. There was a 4.9% major complication rate in those in the rigid fixation group versus 15.4% in the nonrigid fixation group (P < .001). Conclusion:
The fixation requirements of patients treated with double fractures of the mandible are different than when treating isolated fractures of the mandible. Double fractures require that at least one of the fractures undergoes rigid fixation to decrease the incidence of complications. Ó 2013 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 71:726-733, 2013 purpose of this study is to examine a large sample of patients treated with rigid or nonrigid fixation for this common mandibular fracture.
Over the past 30 years, the management of mandibular fractures has changed from intermaxillary fixation (IMF) with or without internal wire fixation to internal plate and/or screw fixation and no IMF. While the use of plate and/or screw fixation has potential benefits for the patient, complications are not uncommon.1-6 The most common mandibular fracture pattern seen in most major medical centers in the United States is the combination of an angle fracture (usually the left side)3-7 combined with a contralateral fracture of the mandibular body or symphysis. Although studies have been published that have evaluated internal fixation schemes for isolated fractures of the angle6,8 or body/symphysis,9-11 no studies have specifically evaluated the fixation requirements for the mandible that has fractures through both the angle and the contralateral body or symphysis. The
Patients and Methods All dentate patients treated for combined fractures of the mandibular angle and contralateral body or symphysis from July 1, 1993 through December 31, 2012 were included in this study. Inclusion criteria were 1) simple (linear) fractures through the angle and the contralateral body or symphysis; 2) neither fracture was grossly infected at time of treatment; 3) open reduction and internal fixation (ORIF) of the angle fracture through intraoral approach and application of a single 2 mm miniplate (1 mm thick) along the superior border (Champy technique);12 4) ORIF of contralateral body or symphysis fracture through a transoral approach using a variety of plate and/or screw techniques; 5) no postoperative IMF, 6) age > 15 years; and 7) 6-12 weeks of follow-up. Exclusion criteria were 1) comminution of either fracture; 2) gross infection of either fracture; and 3) insufficient records and/ or follow-up. A large number of residents were involved in the surgeries, but faculty was always scrubbed. The Internal Review Board determined that their review of this project was unnecessary
*Professor and Chair, Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center, San Antonio, TX. Address correspondence and reprint requests to Dr Ellis: Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center, 7703 Floyd Curl Drive, MC7908, San Antonio, TX 78229-3900; e-mail: [email protected] Ó 2013 American Association of Oral and Maxillofacial Surgeons 0278-2391/12/7008-0$36.00/0 http://dx.doi.org/10.1016/j.joms.2012.09.017
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FIGURE 1. Examples of rigid fixation applied to the mandibular body/symphysis fractures. A, 2 lag screws. B, 2.4-mm dynamic compression plate. C, two 2-mm miniplates (1 mm thick). (Fig 1 continued on next page.) Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
because of the removal of patient identifiers. The surgical technique for the treatment of the fractures has been described in other publications.3,6,9 In addition to demographic information (ie, gender, age, cause, etc), the following data on all cases were prospectively collected: 1) location of angle fractures (ie, left versus right); 2) site of body or symphysis fracture; 3) presence of a tooth in the line of the fractures; 4) extraction of tooth in line of fracture; 5) internal fixation techniques for the
body or symphysis fracture; 6) occlusal relationship at last follow-up visit; and 7) major postsurgical complications, which were defined as a need for further surgical intervention. Simple wound care delivered in the clinical setting, including prescription of antibiotics for minor wound infection and use of elastics for slight malocclusion, was not considered a major complication. The sample was divided into 2 groups based on the fixation schemes used for the body or symphysis
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FIGURE 1 (Cont’d.) D, 2-mm locking plate (much thicker and stronger than standard 1-mm-thick miniplates). E, 2-mm locking plate with a smaller, thinner miniplate placed above it. F, 2.4-mm reconstruction bone plate. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
fractures. The rigid group was defined as having one of the following fixation schemes used on the body or symphysis fracture: 1) at least two 2.4-mm lag screws with an arch bar (Fig 1A); 2) one 2.4-mm compression plate with an arch bar (Fig 1B); 3) two 2-mm noncompression locking or nonlocking miniplates (1 mm thick) with an arch bar (Fig 1C); 4) one 2-mm locking mandibular bone plate (Fig 1D) (Synthes 447.103; 447.014; 447.105; 447.106, Paoli, PA) (all are thicker and much stronger than standard 1-mm-thick miniplates) with or without a second plate (Fig 1E) and an arch bar; and 5) a nonlocking 2.7-mm or locking 2.4-mm reconstruction bone plate with or without an arch bar (Fig 1F). The nonrigid group was defined
as having a single 2-mm noncompression locking or nonlocking miniplate (1 mm thick) placed across the body or symphysis fracture with an arch bar (Fig 2). The 2 groups were compared for differences in demographic characteristics using c2 cross-table analysis for discontinuous variables or Student t test for continuous variables. Outcomes for the 2 groups were similarly analyzed.
Results A total of 976 patients were included in the rigid group. They ranged in age from 15 to 59, with a mean of 29.2 years. There was an overwhelming
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FIGURE 2. Radiograph showing a single 2-mm miniplate (1-mm thick) applied to both fractures. This is an example of nonrigid fixation. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
predominance of males (n = 893) and left-sided angle fractures (n = 644). Altercations were the predominant cause (n = 879), followed by motor vehicle accidents (n = 49), falls (n = 34), and others (n = 14). Treatment of the body or symphysis fractures in the rigid sample included 1) lag screws (n = 141); 2) compression plate (n = 95); 3) 2 miniplates (n = 379); 4) 2-mm locking mandibular plate (n = 306); and 5) reconstruction bone plate (n = 55). A total of 149 patients were included in the nonrigid group. They ranged in age from 16 to 54, with a mean age of 28.4 years. There were 134 males, and the left angle was involved 101 times. Altercations were involved in 129 cases, motor vehicle accidents in 8, falls in 8, and other causes in 4. There was no significant difference in the demographic characteristics of the 2 groups. In the rigid group there were 48 major complications (4.9%) requiring surgical intervention. There were no cases of malocclusion requiring secondary intervention. Twelve complications were at the site of the body fracture. All others were located at the site of the angle fracture. Eight of the complications located at the body/symphysis fracture site were wound problems with dehiscence of the incision and exposure of the bone plate; in four other cases, there was associated infection. These all required surgery to remove the bone plates and to treat any infection present. The remaining 36 complications all presented as wound problems at the site of the angle fracture. Nineteen presented as infections with either abscess formation (n = 7) or drainage of purulent material intraorally (n = 8) or extraorally (n = 4). All 19 patients underwent incision and drainage through an intraoral (n = 13) or extraoral approach (n = 6) and either immediate or subsequent hardware removal in 15 patients. In 5 patients, there was no bony union at the time of plate
removal and a period of IMF was used. One of these did not unite and required bone grafting 4 months later. The remaining 17 patients presented with noninfected wound problems. Typically, they had granulation tissue around the incision site (Fig 3), plate and/ or bone exposure, and (in 7 cases) loose hardware. All of these patients required surgery to remove the bone plate and debride any nonvital bone. In only 4 patients was the fracture not united at the time of plate removal. In these patients, a period of IMF was used. In the nonrigid group, there were 23 major complications (15.4%), of which 22 were postoperative wound problems. Fourteen presented as a noninfected wound problem with granulation tissue, plate and/or bone exposure, and (in 9 cases) loose hardware. The wound problem occurred at the angle fracture site in 8 cases, at the body fracture site in 2 cases, and at both sites in 4 cases. Removal of hardware and
FIGURE 3. Typical appearance of wound problem characterized by granulation tissue, dehiscence, and/or exposed bone and hardware. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
730 nonvital bone was performed through transoral approaches from 4 weeks to 8 weeks after fracture treatment. The fractures had healed in 8 of the cases, but 6 had mobility at the time of hardware removal and were placed into IMF for a period of time. All eventually went on to osseous union. Eight cases had frank infection, 7 at the angle fracture site and 1 at the body fracture site. The infections presented with abscess formation without spontaneous drainage in 4 cases and intraoral purulent drainage through the incision site in the others. All infections required intraoral incision and drainage, and 7 required hardware removal (4 at the time of incision and drainage at between 4 and 7 weeks, and 3 at 8 weeks). At the time of hardware removal, 3 had mobility and required a period of IMF to obtain union. There was only one case of malocclusion requiring secondary intervention. This complication was noted 4 weeks postoperatively. The radiograph reported that the plate on the body fracture had undergone slight in-line deformation and a small step between the teeth on each side of the fracture developed, resulting in the malocclusion (Fig 4). In this case, there was a tooth in the fracture line that was removed at the time of treating the body fracture. This case required surgery to remove the plate, reestablish the proper occlusion, and provide stable internal fixation. There was a statistically significant difference in the major complication rate between the rigid and nonrigid groups (P < .001).
Discussion Bilateral fractures occur in over half of the patients who present with mandibular fractures.3,4,7,13-17 The most common mandibular fracture seen in most
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medical centers in developed nations is an angle fracture combined with a contralateral fracture of the mandibular body or symphysis.3,4,7,16-18 The reason for this is that most of them are caused by interpersonal violence with a blow to the side of the face.3-8,16,17 In spite of their prevalence, the specific fixation requirements for combined angle and contralateral body/symphysis fractures has not been addressed to any extent in the literature. In fact, fixation requirements for bilateral mandibular fractures are not even mentioned in either of the AO/ ASIF’s Manual of Internal Fixation of the CranioFacial Skeleton.19,20 One might question whether the fixation requirements for a combined angle/body or angle/symphysis fracture is the same as what one might use for an isolated angle or an isolated body or symphysis fracture. The results of this study show that the fixation requirements for a bilateral fracture can be different from what is required for an isolated (single) fracture to achieve sufficient stability during the healing period. To better understand the fixation requirements of these fractures, some definitions are helpful. Rigid internal fixation is a term applied to the application of sufficient internal hardware to prevent movement across the fracture site when normal functional forces are in effect. Examples of rigid internal fixation include locking/nonlocking reconstruction bone plates, multiple bone plates at the fracture site, single strong nonreconstruction bone plates, or multiple lag screws. All are of sufficient strength to prevent interfragmentary motion during function and allow primary osseous union to proceed. Anything less than rigid is, by definition, nonrigid. Nonrigid fixation spans a continuum from almostcompletely rigid to completely mobile (eg, intraosseous
FIGURE 4. Radiograph showing in-line deformation of the bone late applied to the body/symphysis region of the mandible, with resulting malocclusion. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
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FIGURE 5. Demonstration of the biomechanics of combined angle and contralateral condylar process fractures. A, Mandibular model showing a single miniplate applied to the left angle fracture and the right condylar process fracture that has not been treated. B, Model is being loaded on the right posterior mandible. Note the torsion that occurs at the inferior border of the mandible at the angle fracture. The miniplate is not capable of preventing this because it is not strong enough. C, Illustration showing that a single miniplate cannot prevent the tendency for widening of the mandible. D, Mandibular model being similarly loaded as in 5B but with rigid fixation (2 miniplates) applied to the angle fracture. This fixation is able to prevent torsional separation at the inferior border at the angle fracture. E, Illustration showing stable fixation has been applied to the right condylar process and nonrigid (single miniplate) fixation has been applied to the left angle fracture. Because of the continuity and stability across the right temporomandibular joint by the bone plate in the subcondylar region, the nonrigid fixation of the angle fracture becomes functionally stable, and the patient does not need postoperative IMF. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
wire). Nonrigid fixation can, however, become functionally stable fixation. Functionally stable fixation is not rigid fixation but is the application of various hardware schemes which do not prevent micro-motion across the fracture site during function, but permit healing of the fracture by secondary bone healing (with formation of callous) and without IMF. Examples of nonrigid fixation that are functionally stable are the use of a single titanium miniplate for a fracture of the angle of the mandible (Champy technique)12or a single titanium miniplate for a fracture of the body
or symphysis of the mandible. The original Champy technique used stainless steel miniplates that were 1 mm thick. For fractures of the mandible, the fixation provided by these plates might be considered ‘‘rigid fixation,’’ because they were much stronger than the 1-mm-thick titanium miniplates currently available from most manufacturers. Therefore, one must consider this when using the fixation recommendations of Champy’s original work with the plates we currently have available. It has been reported in many studies that when treating mandibular fractures, rigid fixation is not
732 always necessary, and there are multiple functionally stable hardware constructs that result in healing and excellent postoperative results.4,5,8,21-24 The results of this study show a significantly higher rate of wound problems when both fractures are treated with nonrigid fixation. This indicates that although nonrigid forms of fixation may work on isolated (single) fractures of the mandible, they might not be reliable when used on more than one fracture of the mandible. This should not be surprising when one considers the difference in the biomechanics of mandibular function with single versus double fractures. The easiest way to understand the differences in biomechanics might be to consider an angle fracture combined with a contralateral condylar process fracture (Fig 5A). The bone fragment between the 2 fractures becomes a free-floating fragment that can be readily displaced by functional loads. If one chooses to treat the condylar fracture closed, the forces acting across the fracture of the angle become more complex than with an isolated fracture of the angle, with a torque moment of the fragment between the 2 fractures. Because of the length of the fragment (from the angle to the contralateral condylar process), the torque moment arm is long, and the force is large. If the angle fracture is treated with a single titanium miniplate at the superior border according to Champy,12 torquing of the fragments at the inferior border can occur with mandibular function and occlusal loading on the side of the condylar process fracture (Fig 5B). Additionally, with loss of the craniomandibular articulation on the left side, there is little resistance to widening of the mandible from the titanium miniplate applied to the angle fracture, and a gap can form on the lingual cortex (Fig 5C). The fixation applied to the angle, therefore, must be stronger than fixation required for an angle fracture in isolation. Based on the results of this study, rigid internal fixation should be applied to the angle fracture if the condyle fracture is to be treated closed. In this scenario, a stronger bone plate or 2 miniplates could be applied to rigidly stabilize the angle fracture and prevent separation of the fragments at the inferior border (Fig 5D). On the other hand, if the condylar fracture were to be made stable by open reduction and internal fixation, one could essentially turn a bilateral fracture into an isolated angle fracture, allowing less fixation (ie, single miniplate) to be applied to provide a functionally stable result (Fig 5E). What fixation should be applied to a combined angle plus contralateral body or symphysis fracture? Because the second fracture changes the biomechanics acting across the fractures, it is possible that single
FRACTURES: HOW MUCH FIXATION IS ENOUGH?
titanium miniplates applied to both fractures cannot counter the more complex forces working on the dento-osseous fragment between the 2 fractures, and there can be a tendency for the fracture fragments to separate or twist under function (Fig 6A). On the basis of the results of this study, the most predictable fixation scheme is to treat at least one of the fractures with rigid internal fixation, and to treat the other with nonrigid fixation. By doing so, a bilateral (double) fracture of the mandible is converted to a unilateral (single) fracture, for which the biomechanics are less complex. The entire construct then becomes functionally stable. In practice, it is easier to perform rigid fixation of the more anterior fracture, and so
FIGURE 6. Illustrations demonstrating the potential problem of treating combined angle and contralateral body or symphysis fractures with nonrigid fixation. A, The intervening segment of the mandible between the 2 fractures can undergo torquing from occlusal and muscular forces acting on it, allowing separation of the fractured fragments from one another. B, The application of rigid fixation of the body/symphysis fracture (in this case by a larger, stronger plate) allows the nonrigid fixation at the angle fracture (by a miniplate) to become functionally stable, obviating the need for postoperative IMF. Edward Ellis III. Fractures: How Much Fixation Is Enough? J Oral Maxillofac Surg 2013.
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the symphysis or body fracture is treated with 2 lag screws, 2 miniplates, or a stronger bone plate combined with an arch bar, and the angle fracture is then treated with a single miniplate (Fig 6B). Summarizing, fixation that may have been functionally stable on a fracture in isolation may become unstable in a mandible with more than one fracture. Because the second fracture changes the biomechanics acting across the fractures, it seems prudent to apply hardware with increased rigidity and strength on at least one of the fractures when treating bilateral fractures of the mandible.
References 1. Ellis E 3rd, Sinn DP: Treatment of mandibular angle fractures using two 2.4 mm dynamic compression plates. J Oral Maxillofac Surg 51:969, 1993 2. Ellis E 3rd, Karas N: Treatment of mandibular angle fractures using two mini dynamic compression plates. J Oral Maxillofac Surg 50:958, 1992 3. Ellis E 3rd, Walker L: Treatment of mandibular angle fractures using two noncompression miniplates. J Oral Maxillofac Surg 52:1032, 1994 4. Ellis E 3rd, Walker LR: Treatment of mandibular angle fractures using one noncompression miniplate. J Oral Maxillofac Surg 54:864, 1996 5. Feller KU, Schneider M, Hlawitschka M, et al: Analysis of complications in fractures of the mandibular angle—A study with finite element computation and evaluation of data of 277 patients. J Craniomaxillofac Surg 31:290, 2008 6. Ellis E 3rd: A prospective study of 3 treatment methods for isolated fractures of the mandibular angle. J Oral Maxillofac Surg 68:2743, 2010 7. Paza AO, Abuabara A, Passeri LA: Analysis of 115 mandibular angle fractures. J Oral Maxillofac Surg 66:73, 2008 8. Barry CP, Kearns GJ: Superior border plating technique in the management of isolated mandibular angle fractures: A retrospective study. J Oral Maxillofac Surg 65:1544, 2007
733 9. Ellis E 3rd, Ghali GE: Lag screw fixation of mandibular angle fractures. J Oral Maxillofac Surg 49:234, 1991 10. Ellis E 3rd: A study of 2 bone plating methods for fractures of the mandibular symphysis/body. J Oral Maxillofac Surg 69:1978, 2011 11. Ellis E 3rd: Is lag screw fixation superior to plate fixation to treat fractures of the mandibular symphysis? J Oral Maxillofac Surg 70:875, 2012 12. Champy M, Lodde JP, Schmitt R, et al: Mandibular osteosynthesis by miniature screwed plates via a buccal approach. J Maxillofacial Surg 6:14, 1978 13. James RB, Fredrickson C, Kent JN: Prospective study of mandibular fractures. J Oral Surg 39:275, 1981 14. Chuong R, Donoff RB, Guralnick WC: A retrospective analysis of 327 mandibular fractures. J Oral Maxillofac Surg 41:305, 1983 15. 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, 1985 16. Fox AJ, Kellman RM: Mandibular angle fractures: Two-miniplate fixation and complications. Arch Facial Plast Reconstr Surg 5: 464, 2003 17. Guimond C, Johnson JV, Marchena JM: Fixation of mandibular angle fractures with a 2.0-mm 3-dimensional curved angle strut plate. J Oral Maxillofac Surg 63:209, 2005 18. Lamphier J, Ziccardi V, Ruvo A, Janel M: Complications of mandibular fractures in an urban teaching center. J Oral Maxillofac Surg 61:745, 2003 19. Prein J (ed): Manual of Internal Fixation in the Cranio-Facial Skeleton: Techniques Recommended by the AO/ASIF Maxillofacial Group. Berlin, Germany: Springer, 1998 20. Ehrenfeld M, Manson PN, Prein J (eds): Principles of Internal Fixation of the Craniomaxillofacial Skeleton. Trauma and Orthognathic Surgery. Stuttgart, Germany: George Thieme Verlag, 2012 21. Cawood JI: Small plate osteosynthesis of mandibular fractures. Br J Oral Maxillofac Surg 23:77, 1985 22. Kroon FH, Mathisson M, Cordey JR, Rahn BA: The use of miniplates in mandibular fractures. An in vitro study. J Craniomaxillofac Surg 19:199, 1991 23. Tate GS, Ellis E 3rd, Throckmorton G: Bite forces in patients treated for mandibular angle fractures: Implications for fixation recommendations. J Oral Maxillofac Surg 52:734, 1994 24. Potter J, Ellis E 3rd: Treatment of mandibular angle fractures with a malleable noncompression miniplate. J Oral Maxillofac Surg 57:288, 1999