Management of Mandibular Fractures in Children

233 Management of Mandibular Fractures in Children Jiunn-Tat Lee, Tzong-Bor Sun, Li-Fu Cheng, Chien-Hsin Wang, Sou-Hsin Chien* Division of Plastic Surgery, Department of Surgery, Buddhist Tzu-Chi General Hosptal, Hualien and Dalin* Branch, Taiwan Twelve children under 11 years of age with mandibular fractures were treated at Buddhist Tzu-Chi General Hospital between January 1991 and December 2000. This comprised 2.7% of all the 439 patients with mandibular fractures. Five (1.1%) were younger than 5 years of age, and the remaining 7 (1.6%) were 6 to 11-year old. Traffic accidents were the most common cause of mandibular fractures in our series (9 patients, or 75%). There were 17 fracture sites in these 12 children. Four (33%) patients had more than one fracture sites. Seven (41%) of the fractures involved the symphysis, which was the most common fracture sites in our series. Associated injuries were present in 6 (50%) patients. Three (25%) patients had severe associated injuries (one, intracranial injury and two, thoracoabdominal trauma). Methods of treatment included: observation in 4 patients, closed reduction in 2 patients and open reduction and internal fixation in 6 patients. We did not use arch bars. When maxillomandibular fixation was indicated, it was obtained with a combination of dental splints, circummandibular wires and piriform aperture wires. (J Plast Surg Asso R.O.C. 2003;12:233~243) Key words: mandibular fractures in children, maxillomandibular fixation ( MMF ), open reduction and internal fixation ( ORIF ), closed reduction, dental splint Introduction Mandibular fractures in the pediatric patient population are relatively uncommon compared with those in adults 1~8. They are considered separately because of specific problems that arise in their management. In children, because deciduous teeth may either be insufficient in number or their roots may be resorbed, and permanent teeth may be incompletely erupted, it is more difficult to use the teeth for fixation. The poor retentive shape of the crown is also not favorable for application of wires and splints 1. Besides, maxillomandibular fixation (MMF) in pediatric patients may create several

234 Management of Mandibular Fractures in Children concerns, such as cooperation, compliance and adequate nutritional intake. There has been a trend to avoid the use of or shorten the periods of MMF, especially in very young children. In children older than 9 years of age, conventional MMF with arch bars can be achieved easily. In addition, ankylosis of the temporomandibular joint and facial growth disturbance are more common in children. On the other hand, pediatric fractures heal more rapidly due to the high osteogenic potential and therefore require shorter periods of fixation. Bone union usually takes place within 3 weeks and delay in treatment may result in subsequent malunion. Buddhist Tzu-Chi General Hospital was a regional referral center for facial trauma in eastern Taiwan. Here we have treated more than 1000 cases of facial bone fractures since 1988. Because mandibular fractures in children are considered more unusual, we review our records to determine the incidence, the etology, and the anatomic distribution and to reevaluate our treatment and the outcome of these patients. Patients and Methods A total of 439 patients were admitted to the Buddhist Tzu-Chi General Hospital for treatment of mandibular fractures during the 10-year period between January 1991 and December 2000. Twelve (2.7%) of these 439 patients were children younger than 11-years-old, they formed the material for this study. Children older than 11 years of age were not included because they may have passed the mixed dentition stage and receive treatments the same as in adults. Patient age, sex, mechanism and anatomic location of fracture, associated injuries, treatment method, and clinical outcome were all recorded from retrospective chart review and recall survey. Patient follow-up ranged from 4 months to 4 years with an average of 9 months. Fractures were diagnosed by clinical examination and radiographic findings. The fracture sites were classified as follows: symphyseal, body, angle, ramus, condylar, alveolar, and combinations of these in bilateral fractures. Our methods of treatment (Table 1) included: (1) on soft diet and immediate jaw mobilization for green-stick, undisplaced and condylar fracture. (2) closed reduction and fixation with dental splint secured with circummandibular wires for mildly displaced fractures. (3) open reduction and internal fixtion (ORIF) for mildly displaced fractures when dental splint is not available. (4) ORIF supplemented by additional fixation with dental splint secured with circummandibular wires for moderately displaced fractures. (5) ORIF supplemented by additional fixation with dental splint secured with circummandibular wires and piriform aperture suspension wiring for severely displaced fractures and multiple fractures. Table 1. Methods of treatment for pediatric mandibular fractures 1. Observation & soft diet 2. Closed reduction dental splint Wire fication 3. ORIF Rigid fixation 4. ORIF + dental splint 5. ORIF + dental splint piriform aperture suspension wiring 年

Jiunn-Tat Lee, Tzong-Bor Sun, Li-Fu Cheng, Chien-Hsin Wang, Sou-Hsin Chien 235 Results Twelve children were under 11 years of age, comprising 2.7% of all the 439 patients with mandibular fractures diagnosed and treated between January 1991 and December 2000 at Buddhist Tzu-Chi General Hospital (Table 2.). The patients ages ranged from 1 year and 5 months to 9 years and 2 months (mean 6 years). Three of the patients were males and 9 were females. Five (1.1%) were younger than 5 years of age, and the remaining 7 (1.6%) were 6 to 11 years old (Fig. 1). Traffic accidents were the most common cause of mandibular fractures in our series (9 patients, or 75%). Falls from height resulted in mandibular fractures in 3 (25%) patients. The mechanisms of injury are shown in Table 3. There were 17 fracture sites in these 12 children. Four (33%) patients had more than one fracture sites, among them three had 2 fracture sites and one had three fracture sites. Seven (41%) of the fractures involved the symphysis, which was the most common fracture sites in our series. Five fractures involved mandibular body, 2, the alveolar process, 2, condyle, and 1, angle. The distribution of the fracture sites is shown in Table 4. Associated injuries were present in 6 (50%) patients (Table 5.). Three (25%) patients had severe associated injuries (one with intracranial injury and two with thoracoabdominal traumas) and needed admission to the intensive care unit for initial life supportive care. There was no mortality in our series. Conservative treatment with soft diet and immediate jaw mobilization was the method of treatment in four (33.3%) patients with green-stick, undisplaced linear fractures and condylar fracture. Two alveolar process fractures was treated with close reduction with (1 patient, dental splint + circummandibualr wiring) or without (1 patient) fixation. Six (50%) patients required ORIF with an intraosseous wire (5 patients) or miniplate (1 patient). ORIF was required in displaced fractures, multiple fractures, and fractures of the mandibular angle (Fig. 2A, B). Among these six patients, one required additional fixation with dental splint with circummandibular wiring, and two required additional fixation with denatl splint with circummandibular wiring and piriform aperture suspen- sion wiring for MMF (Fig. 3A, B, C, D). Dental splints were used with (2 patients) or without (2 patients) MMF to facilitate reestablishment of the preinjury occlusal relationship and to offer supplemented fixation in 4 patients. Dental splints were fabricated from models of the maxillary and mandibular dentition by our dental colleague. Mandibular impressions were obtained after closed digital reduction of the fractures. The preliminary casts of the mandible obtained as just described then underwent model surgery to reposition and realign the mandi- bular arch using the cast of the maxillary arch as a guide (Fig. 3B). An acrylic dental splint was then constructed (Fig. 3C). These splints were secured with circummandibular wires for monomaxillary fixation in two patients. Additional piriform aperture suspension wiring was done for MMF in two patients with displaced and multiple fractures (Fig. 3D). J.P.S.A.R.O.C. 2003. Vol 12 No.4

236 Management of Mandibular Fractures in Children All patients in this series were followed up with an average of 9 months. The following complications were noted. Wound infection developed in one patient who had ORIF with intraosseous wire and it subsided after oral antibiotic treatment. Slight malocclusion was detected in a 7-year and 2-month old girl (patient 10) with alveolar process fracture and the condition still persisted until the age of 12 years. Mouth deviation during opening and hypertrophic scar was seen in one patient. Malunion and nonunion were not observed in our series. Maximal mouth opening was not significantly altered after treatment. Long term follow-up was difficult because of frequent migration of most patients. Table 2. Treatment of pediatric mandibular fractures Case Age Sex Fracture site Treatment Complication 1 3y6m F Symphysis Observation Non 2 7y11m F Bilateral body ORIF with wire + dental splint + circummandibular wiring + piriform aperture suspension wiring Non 3 7y7m F Body Observation Non 4 9y2m F Symphysis + body 5 1y5m F Symphysis ORIF with wire + dental splint + circummandibular wiring +piriform aperture suspension wiring ORIF with miniplate + dental splint + circummandibular wiring Non Non 6 4y8m F Symphysis ORIF with wire Non 7 4y0m M Symphysis ORIF with wire Wound infection 8 1y8m M Alveolar process Closed reduction Non 9 7y10m F Body Observation Non 10 7y2m F Alveolar process Closed reduction + dental splint + circummandibular wiring 11 7y1m F Symphysis + angle ORIF with wire for angle fracture 12 9y2m M Symphysis + bilateral condyle Observation Slight malocclusion Mouth deviation, hypertrophic scar Non 年

Jiunn-Tat Lee, Tzong-Bor Sun, Li-Fu Cheng, Chien-Hsin Wang, Sou-Hsin Chien 237 9 8 7 6 5 4 3 2 1 0 5 2 2 2 1 1 2 3 4 5 6 7 8 9 10 11 age(years) Fig. 1. Age distribution Table 3. Etiology of fractures Type No. of patients Road traffic accidents 9 Car 4 Motorcycle 3 Bicycle 1 Pedestrian 1 Fall 3 Total 12 Table 4. Site of fracture Site Patients (n) Symphysis 4 Body 2 Alveolar process 2 Symphysis + body 1 Symphysis + angle 1 Bilateral body 1 Symphysis + bilateral condyle 1 Total 12 Table 5. Associated injuries Type No. of patients Intracranial injury 1 Thoracoabdominal trauma 2 Extremity fractures 1 Clavicle fracture 1 Multip rib fractures 1 Fig. 2B Fig. 2A Fig. 2 Patient 11. (A) 7-year and 1-month girl had symphyseal and left angle fractures due t o traffic acciden t (B) ORIF with intraosseou s wire was done for left angle fracture. J.P.S.A.R.O.C. 2003. Vol 12 No.4

238 Management of Mandibular Fractures in Children Fig. 3A Fig. 3B Fig. 3C Fig. 3D Fig. 3 Patient 4. (A) 9-year and 2-month girl had symphyseal and right body fractures due to traffic accident (B) Mandibula r cast (C) Constructed dental splint (D) The patient was treated by ORIF with wire + dental splint + circummandibular wiring + piriform aperture suspension wiring Discussion Facial bone fractures occur infrequently in pediatric populations. Factors contributing to the low incidence of pediatric facial fractures include: living in a protected environment, thick overlying soft tissue, elasticity of the developing bone and low facial-to-cranial proportions. Excluding nasal bones, the most common injuried facial bone in children is the mandible. The incidence of mandibular fracture in children under 10 or 11 years of age is reported to be 1.8-6.1% of all patients with mandibular fractures 1,3,9,10. The incidence is even more low, approximating only 1%, in children under 5 years of age 1,11. Our series results, 1.1% in children younger than 5 years, and 2.7% in children younger than 11 years old, are close to previous reports (Table 6). The incidence of mandibular fractures increases from birth through 15 years in a 年

Jiunn-Tat Lee, Tzong-Bor Sun, Li-Fu Cheng, Chien-Hsin Wang, Sou-Hsin Chien 239 gradual progression 1. Table 6. Mandibular fractures in children Authors Year published Age group (years) Total in series Children (%) Hagar & Huelke(11) 1961 0-5 319 1.2 Ellis et al.(9) 1985 0-11 2137 1.8 Bochlogyros(10) 1985 0-10 853 6.1 Amaratunga(1) 1988 0-5 818 1 Amaraturga(1) 1988 0-11 818 4.5 Chen & Chen(3) 1990 0-10 354 3.4 Present study 0-11 439 2.7 Many previous studies demonstrated that condyle was the most common site of pediatric mandibular fractures, especially in young age group children 1,4~7,12,13. Whereas some reports found that symphysis 8 or body 2,3 to be the most common site. Our series showed that involvement of the symphysis occurred most frequently, in 41% of fractures, either alone or in combination with other fractures. We have less condylar fractures and this was similar to Chen s series 3. The difference in the anatomical distribution of the fractures could be explained by the variation of the etiologic factors in a particular regions and the difference of the age group in each study. Thoren et al stated that the relative frequency of condylar fractures decreased and those of the body, angle and ramus increased with increasing age 6. The number of mandibular fractures per patient in our study was 1.6, which compares with Hagan and Huelke s statistic of 1.8 fractures per patient 11. These statistics emphasize the importance of searching for a second fracture site in the mandible when one site is discovered. Condylar fractures are the most commonly overlooked site. The most common cause of mandibular fractures in our series was road traffic accidents, which represented 75% of all cases. Falls from height was the next most common causes. This is in agreement with the findings of some previous studies 4,6 but different from others 1,2,5,7,8. There was no sport injury, altercation and child abuse in our study group. Because of limited numbers of our series, no relationship between age and cause could be demonstrated. A high association of concomitant injuries with pediatric mandibular fractures has been noted in previous reports 4,5,14. Because the size of the facial bones is small in children, compared with that of the cranium, the relatively protected mandible is fractured only after the exposed cranium and/or the thoracoabdominal cavity and/or the extre- mities are injuried. Siegel et al. reported 53% of the patients under 6 years had associated injuries, whereas only 33% of J.P.S.A.R.O.C. 2003. Vol 12 No.4

240 Management of Mandibular Fractures in Children the patients 7 to 12 and 17% of the patients 13 to 18 had associated injury 5. In our series, we had 6 (50%) of 12 children with associated injuries. Among these 6 patients, 3 had associated intracranial or thoracoabdominal traumas severe enough to make them admit to the intensive care unit for initial life support necessity. This percentage is significantly higher than in our adult population. Management of mandibular fractures in the pediatric patient depends on the location and severity of the fractures and the patient s dental status. Methods of treatment include: 1.observation and soft diet, 2. closed reduction and fixation with splint or arch bars 3. open reduction and internal fixation with wire or miniplate. We agree with the opinion of many previous reports that treatment of mandibular fractures in children is usually conservative with observation, soft diet, closed reduction with splint and MMF 1,5,6,8. A main explanation for this is that the majority of pediatric mandibular fractures, especially in patients under 10 years of age, were condylar fractures which are usually treated conservatively 6. Four (33.3%) of 12 patients in our series was treated with observation. In other studies, a certain proportion (24.3%~51.6%) of patients required no intervention too 1,5,6. When closed reduction was required, we recommended the use of dental splints to facilitate reestablishment of the preinjury occlusal relationship and to offer supplemented fixation. These splints were secured with circummandibular wires for monomaxillary fixation 2-4,7. When MMF is indicated, skeletal fixation can be added by using piriform aperture wires which are passed beneath the circummandibular wires. We do not use arch bars for MMF in this series. Although some authors used them without difficulty 1,5. Open reduction is indicated only when the fractures segments were excessively displaced or when there are multiple fractures, but special precaution might pay for avoiding the injury to the tooth buds. In our series, traffic accidents were the most common cause of mandibular fractures and they resulted in more displaced and multiple fractures and less condyle fracture. This explained why ORIF was done more frequently (50%) in our series. Our results were similar to Chen s and Sherick s series 3,15. Sherick et al reported that plastic surgeons used open techniques more frequently than closed in the treatment of pediatric mandibular fractures, whereas oral surgeons used open and closed techniques with equal frequency 15. Two main concerns about open reduction and internal fixation for the management of pediatric mandibular fractures are facial growth disturbance and tooth bud injury. When open reduction techniques are used, great care should be taken. Wires, plates and screws must be placed at the extremes of the inferior borders of the mandible in order to avoid injury to the tooth buds. When ORIF with intraosseous wires was done, additional stabilization in the form of a splint or intermaxillary fixation may be necessary 4. Recently, treatment of mandibular fractures with a mini-plate in adult has become popular, and there has been an increasing trend toward the use of miniplate and screw fixation in pediatric facial fractures requiring open reduction and thus avoiding the use of or shorten the periods of maxillomandibular fixation, especially in very young children 16,17. Posnick et al reported that these rigid internal fixation techniques were the most common method of stabilization in 63 per cent of cases, 年

Jiunn-Tat Lee, Tzong-Bor Sun, Li-Fu Cheng, Chien-Hsin Wang, Sou-Hsin Chien 241 followed by wire fixation in 16 per cent of cases 16. However, the suitability of rigid internal fixation for children remains controversial. Many concern about whether the implanted hardware in the mandible of a growing child will interfere with facial growth or not. For these reasons, some have suggested routine removal of metal fixation once stable osteosynthesis has been achieved 7,18. We used ORIF with miniplate in a 1-year and 5 month-old child (patient 5), who had severely displaced symphyseal fracture, to avoid MMF. The miniplate was removed 3 months later, when bone union had been achieved. However, the indication to remove bone plates applied to a fractured pediatirc mandible after bone healing is still unclertain. Indeed, a second surgical procedure to remove a fixation plate may conceivably induce further scar formation and hinder growth. In 2001, Imola et al reported the use of resorbable plate fixation in pediatric craniomaxillofacial surgery of the upper and middle facial skeleton 18. However, for mandibular fractures, there are still no available resorbable plates which can provide the necessary stability to resist masticatory forces 18. Long-term complications of pediatric mandibular fractures include temporomandibular joint ankylosis, facial growth disturbance, facial asymmetry, micrognathism, malocclusion and open bite. Some authors had the view that discrepencies in alignment and occlusion can often be corrected by the natural remodeling of the bone at the time of eruption of the permanent teeth 1,3. Tanaka s results do not support this view 8. We had one alveolar bone fracture in a 7-year and 2-month-old girl (patient 10), slight malocclusion still persisted after the eruption of the permanent teeth. It is well known that there is a growth center in the condyle, although Moss work suggests that the role of the functional matrix is more important than the condylar growth center 19. Condylar fractures in children can lead to abnormal facial growth and ankylosis of temporomandibular joint more frequently. Lund found that 22% of children showed abnormalities on the side of a fractured condyle 20. In 1999, Demianczuk et al reported that 22% of children age 4 to 7 years, and 17% of children age 8 to 11 years required orthognathic surgery to correct facial growth disturbances following mandibular fractures 13. We can not comment on these issues because of limited patient numbers and poor long-term follow-up in our series. References 1. Amaratunga NA. Mandibular Fractures in Children A Study of Clinical Aspects, Treatment Needs, and Complications. J Oral Maxillofac Surg 1988;46:637-640. 2. Jones KM, Bauer BS, Pensler JM. Treatment of Mandibular Fractures in Children. Ann Plast Surg 1989;23:280-283. 3. Chen CM, Chen YR. Mandibular Fractures in Children-Immediate Reduction and Fixation with Orthodontic Resin. Chang Gung Med J 1990;13: 39-47. 4. Thaller SR, Mabourakh S. Pediatric Mandibular Fractures. Ann Plast Surg 1991;26:511-513. 5. Siegel MB, Wetmore RF, Potsic WP et al. Mandibular Fractures in the Pediatric Patient. Arch Otolaryngol Head Neck Surg 1991;117:533-536. 6. Thoren H, Iizuka T, Hallikainen D et al. Different patterns of mandibular fractures in children. An analysis of 220 fractures in 157 patients. Journal of Cranio-Maxillo-Facial Surgery 1992;20:292-296. J.P.S.A.R.O.C. 2003. Vol 12 No.4

242 Management of Mandibular Fractures in Children 7. Hardt N, Gottsauner A. The treatment of mandibular fractures in children. Journal of Cranio-Maxillo-Facial Surgery 1993;21:214-219. 8. Tanaka N, Uchide N, Suzuki K et al. Maxillofacial fractures in children. Journal of Cranio- Maxillo-Facial Surgery 1993;21:289-293. 9. Ellis E, Moos KF, El-Attar A. Ten years of mandibular fractures: An analysis of 2137 cases. Oral Surg 1985; 59(2):120-129. 10. Bochlogyros PN. A Retrospective Study of 1521 Mandibular fractures. J Oral Maxillofac. Surg 1985;43(8):597-599. 11. Hagan EH, Huelke DF. An analysis of 319 case reports of mandibular fractures. J Oral Surg 1961;19:93-104 12. Lehman J, Saddawi N. Fractures of the Mandible in Children. J Trauma 1976;16(10):773-777. 13. Demianczuk ANA, Verchere C, Phillips JH. The Effect on Facial Growth of Pediatric Mandibular Fractures. The Journal of Craniofacial Surgery 1999;10(4):323-328. 14. Schweinfurth JM, Koltai PJ. Pediatric Mandibular Fractures. Facial Plastic Surgery 1998; 14(1):31-44. 15. Sherick DG, Buchman SR, Patel PP. Pediatric Facial Fractures: Analysis of Differences in Subspecialty Care. Plast Reconstr Surg 1998; 102(1):28-31. 16. Posnick JC, Wells M, Pron GE. Pediatric Facial Fractures: Evolving Patterns of Treatment. J Oral Maxillofac Surg 1993;51:836-844. 17. Wong GB, Marie SS. Pediatric Mandibular Fractures Treated By Rigid Internal Fixation. Journal Canadian Dental Association 1993;59(9):759-764. 18. Imola MJ, Hamlar DD, Shao W et al. Resorbable Plate Fixation in Pediatric Craniofacial Surgery. Arch Facial Plast Surg 2001;3:79-90. 19. Moss ML, Rankow RM. The role of the functional matrix in mandibular growth. Angle Orthod 1968; 38(2):95-103. 20. Lund K. Mandibular growth and remodeling processes after condylar fracture: A longitudinal roentgen cephalometric study. Acta Odontol Scand 1974;32(suppl 64):3-117. 年

Jiunn-Tat Lee, Tzong-Bor Sun, Li-Fu Cheng, Chien-Hsin Wang, Sou-Hsin Chien 243 Reprints request from: Jiunn-Tat Lee, M.D. Division of Plastic Surgery, Departemnt of Surgery, Buddhist Tzu-Chi General Hospital, Hualien, Taiwan Address: 707, Sec. 3, Chung-Yang Rd. Hualien, Taiwan TEL: (03) 8561825 ext 2213 李 立福 年 年 年 療 439 2.7% 1.1% 1.6% 六 車 75% 17 33% 見 symphysis 41% 六 50% 兩 療 兩 復 六 復 arch bars 兩 利 dental splints, circummandibular wires piriform aperture wires 來 J.P.S.A.R.O.C. 2003. Vol 12 No.4