CLINICAL STUDY
Zygomatic Arch Fracture: A New Classification and Treatment Algorithm With Epidemiologic Analysis Jiye Kim, MD,* Seungchan Kim, MD,* Seum Chung, MD, PhD,† and Yoon Kyu Chung, MD, PhD* Abstract: Determining the optimal method for zygoma fracture reduction is a common challenge. Numerous methods for treating zygomatic arch fractures have been suggested. However, a substantial gap exists between suggested treatment strategies and real-world practice. A general consensus of classification and treatment guidelines for zygomatic arch reduction has not yet been established. We reviewed our cases and propose a new classification of zygomatic arch fracture and a treatment algorithm for successful reduction based on the injury vectors. Key Words: Zygomatic arch, classification (J Craniofac Surg 2014;25: 1389–1392)
T
he zygoma is the most prominent portion of the face, and its injury is common in facial trauma. Isolated arch fractures comprise 10% of all zygoma fractures1 and 5% of all facial bone fractures.2 Almost all simple zygomatic arch fractures are treated in a closed fashion with a Dingman elevator using the Gillies approach or the Keen approach. To reduce the zygomatic arch completely, comprehension about the vector of fracture is needed. Some reports recommend open reduction of the zygomatic arch in complex-type fractures; however, there are many difficulties and risks associated with an open approach. The coronal approach carries the risk of having a long scar, scalp numbness, alopecia, or temporal hollowing in addition to the usual risks associated with a long operation time.3 In this report, we reviewed our zygomatic arch fracture cases and propose a new classification and corresponding treatment algorithm. In addition, through analysis of trauma causes and associated factors, we promote an understanding about its treatment and prevention.
METHODS Data Collection We retrospectively reviewed 424 patient’s zygomatic arch views and facial bone computed tomographies, who visited the Wonju Severance Christian Hospital from 2007 to 2010 with zygomaticomaxillary fractures. Of the 424 patients, 113 were purely maxillary fracture patients without zygomatic arch fracture. Exempting From the *Department of Plastic and Reconstructive Surgery, Wonju College of Medicine, Yonsei University, Wonju, Korea; and †National Health Insurance Corporation Ilsan Hospital, Ilsan, Korea. Received December 10, 2013. Accepted for publication February 8, 2014. Address correspondence and reprint requests to Dr. Yoon-kyu Chung, Department of Plastic and Reconstructive Surgery, Wonju College of Medicine, Yonsei University, Wonju Christian Hospital 162 Ilsandong, Wonju, Korea 220-701; E-mail: [email protected] The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000864
the pure maxillary fracture cases, 311 zygomatic arch or zygomaticomaxillary fractures were analyzed. We collected the patient’s data by clinical chart review. Patient’s data include age, sex, and cause of trauma. Statistical analysis was done by Chi-squared analysis.
Fracture Subtype Isolated zygomatic arch fractures were classified as type 1. Zygomaticomaxillary complex fractures involving zygomatic arch fractures were categorized as types 2 or 3. Type 2 fractures are defined by the mechanistic application of force in 1 direction; and type 3, by the application of 2 directions of force. Comminuted zygomatic arch fractures were classified as type 4. Each fracture type is further classified by approximately 1 to 3 subtypes (Figs. 1, 2).
Type 1: Isolated Zygomatic Arch Fracture Type 1A is a typical M-shaped zygomatic arch fracture. It is the simplest type of fracture and easily corrected by the Gillies or Keen procedure (Fig. 1A). Type 1B is a zygomatic arch fracture that developed in the posterior portion. To reduce the fractured segment, a Dingman elevator is inserted into the deep surface to reach the posterior segments. Adequate pointed lever action by the Dingman elevator is important in this subtype of fracture (Fig. 1B). Type 1C is the most unstable fracture type in purely zygomatic arch fractures. Inadequate reduction usually results in a floating fractured segment. If the Gillies or Keen approach is used, accurate targeting insertion of the Dingman elevator under the fractured segment is important. If the fracture is unstable after closed reduction with the Dingman elevator, then we insert the 0.16-mm Kirschner wire (K-wire) into the floating fractured segments with C-arm, and the fracture is reduced by a K-wire (Fig. 1C).
Type 2: Zygomaticomaxillary Fracture (Unidirectional) A type 2 fracture is simply reduced with a K-wire that is inserted on the malar prominence. Type 2A is the same as the malar fracture classification type 5 of Knight and North. The fractured zygomatic body is laterally rotated, and the zygomatic arch is fractured like the M shape. This type of fracture is corrected easily by K-wire reduction with internal rotation of the fracture (Fig. 1D). Maxillary fracture was fixed with internal fixation device through oral incision in conventional method. Type 2B corresponds to Knight and North classification of type 4. The medially rotated zygoma body makes an arch fracture in the “blow-out” shape. This is also corrected by K-wire insertion on the malar body and outward rotation movement with a K-wire (Fig. 1E). Type 2 fracture combines with maxillary fracture, and the lateral buttress fracture line was fixated with internal plate through oral incision as the conventional method. After complete fixation, the inserted K-wire was removed.
Type 3: Zygomaticomaxillary Fracture (Bidirectional) A 3A fracture is similar to the 2A subtype; however, the anterior part of the zygomatic arch is impacted under the posterior zygomatic arch segment. Because type 3 fractures develop from
The Journal of Craniofacial Surgery • Volume 25, Number 4, July 2014
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FIGURE 3. Distribution of fracture subtypes.
Type 3B is also laterally rotated; however, the fracture location of the zygomatic arch is more posterior than for type 2A. With simple medial rotation force, the posterior fractured segment is usually collapsed and becomes an unstable fracture. With rotation force by the K-wire, the posterior fracture segment must be concurrently elevated with Dingman elevator (Fig. 1G). As type 2 fracture, type 3 fracture combines with maxillary fracture, and the lateral buttress fracture line was fixated with internal plate through oral incision as the conventional method.
Type 4: Comminuted Fracture FIGURE 1. Zygomatic arch fracture classification and its reduction (blue dotted arrow, trauma force; red arrow, rotation vector; green line, inserted K-wire on zygoma segment; blue device, Dingman elevator). A, Subtype 1A. B, Subtype 1B. C, Subtype 1C. D, Subtype 2A. E, Subtype 2B. F, Subtype 3A. G, Subtype 3B. H, Subtype 4.
2 directions of force, in type 3 reductions, another assisted reduction force is needed apart from the K-wire on the malar prominence. In the 3A subtype reduction, first, the malar body is elevated anteriorly by an inserted K-wire on the malar body to escape the weight of the posterior zygomatic arch segment. With this anterior reduction force, a second medial rotation force is applied by another inserted K-wire (Fig. 1F).
FIGURE 2. A comparison of preoperative and postoperative zygomatic arch views according to zygomatic arch classification. A, Subtype 1A. B, Subtype 1B. C, Subtype 1C. D, Subtype 2A. E, Subtype 2B. F, Subtype 3A. G, Subtype 3B. H, Subtype 4.
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A type 4 fracture is a comminuted-type fracture. In our cases, all of these types of fractures were open fractures. Through the open wound, we were able to easily approach the fractured segments and treat the fractured bone with plating (Fig. 1H).
RESULTS Isolated zygomatic arch fractures (type 1) comprised 21% (67cases) of the total zygomaticomaxillary fractures (311 cases). Among the subtype groups, 2B fractures were the most common (123 cases, 39% in the total group) (Fig. 3). Of the isolated fractures, type 1A was the most common (44 cases, 65.67% in the isolated fracture group). During the 5 years of collected data, the incidence of zygoma fracture cases gradually increased (Fig. 4). Of the 311 patients, 265 were men, and 46 were women. The largest age group for zygomatic arch fracture incidence was 50 to 59 years (70 patients, 22.5%) (Fig. 5). The second largest group was 40 to 49 years old (68 patients, 21.9%), and the third largest group was 20 to 29 years old (63 patients, 20.3%). In our cases, there were pediatric fractures in those younger than 10 years. For patients in their 40s and 50s, the type 2B fractures were the most common; however, type 2A fractures were more frequent for patients in their 20s. For patients in their 30s, the frequency of type 2A fractures was same as for type 2B. As a result, in the younger age group, 2A subtype was dominant, and in the older age group,
FIGURE 4. Trend of zygomatic arch fracture incidence during a 5-year period.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 25, Number 4, July 2014
Zygomatic Arch Fracture Classification
TABLE 2. Cause of Trauma and Association With Drunken Status Cause of Trauma Motor vehicular accident
FIGURE 5. Age distribution in zygoma fractures.
2B subtype was more frequent. Among all age groups, there was a statistically significant difference in fracture subtype (P = 0.4745) (Table 1). The cause of trauma varied (Table 2). The most common cause was a fall injury. Whether occurring in the outdoors or indoor, zygomatic arch fractures easily develop when a patient loses their feet and collides with something such as a wash basin or a rock, and 23.8% of fall injuries occurred while being drunk. The second most common cause was a traffic accident. Although we expected types 3 and 4 fractures to develop in a high-energy injury such as a motor vehicular accident or a fall injury, there was no statistical significance between the fracture subtype and the cause of trauma. Among associated sports, soccer was most commonly associated with zygomatic fractures.
DISCUSSION The zygoma is the most prominent element of the midfacial bone and is susceptible to local injury. Among midfacial fractures, a zygoma fracture is the second most common injury after nasal bone fracture.4 If not adequately treated, these fractures can result in significant cosmetic deformities and a palpable bony step. If the degree of zygomatic arch deformity is severe, mouth opening function is disturbed, and trismus can even develop. The fundamental method of zygomatic arch reduction is the open approach. With bicoronal incisions, the zygomatic arches are wholly visualized, making accurate reduction possible. Although there are many advantages to the open approach for skeletons, many complications should be considered relating to soft tissue covering the facial bones. With the coronal approach, soft tissue sequelae such as scalp numbness, alopecia, temporal hollowness, and facial nerve injury must be considered.5–7 To avoid these risks from open approach, Keen8 developed the transoral approach to zygomatic arch reduction, and Quinn9 recommended the method of the modified Keen transoral approach. Guilles et al10 used a temporal approach to TABLE 1. Age Groups and Fracture Subtype Distribution Age Group
Drunken Cases
%
61 43 19 6 63 34 33 25 25 14 6 2 2 1 2
3 8 1 1 15
19.6 13.8 6.1 1.9 20.3 10.9 10.6 8.0 7.7
1
0.9
the zygomatic arch, and Gillies approach is the most widely used method today. Since then, numerous closed reduction methods have been suggested to reduce the zygomatic arch involving the methods with a hook,10 mosquito,6 K-wire,3,11,18 and even external suspensory devices.12 However, these efforts are concentrated on the development of a new method of closed reduction. A generally accepted classification and treatment guideline for zygomatic arch reduction has not yet been established. Although some authors suggested simple classification of zygomatic arch, their numbers of cases were insufficient to prove the classification; they simply proposed the closed approach in stable fracture and open approach in unstable fracture.13–15 In this article, we propose a practical algorithm for treating the variable cases of zygomatic arch. We usually use the Gillies procedure to treat type 1 zygomatic arch fractures. In previous articles, pure zygomatic arch fractures account for 5% to 10% of all zygoma fractures.1,7,16 In our data, pure-type zygomatic arch fractures (type 1) comprise 21% of all zygomaticomaxillary fractures. Almost all cases of type 1 fractures were reduced stably with the Gillies approach. However, some unstable fractures could be observed in the subtype 1C fractures. For those cases, we modified Park et al's17 method of external suspension with a K-wire. We inserted the K-wire with C-arm into the unstable fractured segment, and the reduction was done with that K-wire. Another K-wire was inserted into the stable portion of the zygoma to sustain the previously inserted K-wire into the unstable segment. Two K-wires are fixated to each other (Fig. 6), and this temporary fixation is removed 3 weeks after the operation. Type 2 fractures are easily corrected with a K-wire inserted on the malar body. With internal fixation on the lateral buttress and inferior or lateral orbital rim, the zygomatic arch fracture is stably maintained postoperatively.
Fracture Type
Frequency
1A
1B
1C
2A
2B
3A
3B
4
Total
10s
4 8 5 7 11 5 4
0 0 3 2 5 2 1
0 1 0 3 3 2 1
3 26 14 12 15 5 6
15 24 14 23 28 12 4
0 2 1 5 3 5 4
0 3 1 7 2 0 2
0 0 0 1 3 0 1
21 63 37 68 70 30 22
20s 30s 40s 50s 60s 70s
Motorcycle accident Bicycle accident Farm machine accident Slip down injury Fall down injury Assault Industrial accident Sports Soccer Baseball Golf Snowboarding Jogging Miscellaneous
No. Cases
FIGURE 6. Park method of external suspension with a K-wire. A, K-wire for the reduction of fracture segment. B, K-wire for the suspension of A.
P = 0.4745.
© 2014 Mutaz B. Habal, MD
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Type 3 fractures tend to be more difficult to reduce than type 2 fractures. Two or more different vectors are involved in generating this type of fracture, and with only 1 target reduction vector, it can be difficult to obtain an adequate correction of the zygomatic arch. Subtype 3A fractures need 2 directions of traction force to treat the fracture. Subtype 3B fractures need another pushing force under the posterior fracture segment with the Keen approach using a Dingman elevator. In type 4 fractures, the open approach is necessarily needed. However, type 4 fractures are usually high-energy fractures with accompanying soft tissue injury on the zygomatic arch. In our cases, all type 4 fractures were open fractures with an approach through the open wound where internal fixation could be applied. In our 5-year analysis, the frequency of zygomatic arch cases steadily increased. Although efforts have been made to reduce motor vehicular accidents and industrial accidents, the number of zygomatic arch fractures has increased in Korea. Peak incidence is observed in the 50th and 40th decades followed by the 20th decade. Unlike most trauma-related injuries occurring in the 20th and 30th decades of life relating to sports and industrial causes, the cause of zygoma fractures relating to fall injuries or traffic accidents can occur at any age. Contrary to our expectations, the contribution from alcohol drinking was small in motor vehicular accidents and assault. Instead, it contributed in large part to fall injuries. The rate of zygoma fractures in men was quadruple to that of women. Men may be more susceptible to local trauma because of an association with individual drinking habits and harsh occupational activity. In our classification, types 1 and 2 fractures occur by lowenergy mechanisms, and types 3 and 4 occur by high-energy mechanisms. We anticipate high-energy events such as motor vehicular accidents or falls to frequently generate type 3 or 4 injuries. However, in statistical analysis, there was no significant association between trauma cause and fracture type. Among the sports, soccer most commonly resulted in zygoma injuries, perhaps because soccer had more frequent physical fights than other sports.
CONCLUSIONS Except for comminuted zygomatic arch fractures, most zygomatic arch fractures were reduced and sustained with a closed approach. Many articles referred variable methods to reduce the zygomatic arch in a closed approach; however, general treatment guideline according to practical classification was not yet established. With a well-organized classification system and a cautious approach to the zygomatic arch fracture, a good result can be obtained without the need for an open reduction.
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REFERENCES 1. Griffin JE, Max DP, Frey BS. The use of the c-arm in reduction of isolated zygomatic arch fractures: a technical overview. J Craniomaxillofac Trauma 1997;3:27–31 2. Werner JA, Frenkler JE, Lippert BM, et al. Isolated zygomatic arch fracture: report on a modified surgical technique. Plast Reconstr Surg 2002;109:1085–1989 3. Bezuhly M, Lalonde J, Alquhtani M, et al. Gillies elevation and percutaneous Kirschner wire fixation in the treatment of simple zygoma fractures: Long-term quantitative outcomes. Plast Reconstr Surg 2008;121:948 4. Haskell R. Applied surgical anatomy. In: Rowe NL, Williams JL, eds. Maxillofacial Injuries. 2nd ed. Edinburgh: Churchill Livingstone, 1994:1–38 5. Chen CT, Lai JP, Chen YR, et al. Application of endoscope in zygomatic fracture repair. Br J Plast Surg 2000;53:100–105 6. Mezits M, Stathopoulos P, Rallis G. Use of a curved mosquito for reducing isolated zygomatic arch fractures. J Craniofac Surg 2010;21:1281–1283 7. Baek JE, Chung CM, Hong IP. Reduction of zygomatic fractures using the Carroll-Girard T-bar screw. Arch Plast Surg 2012;39:556–560 8. Keen WW. Surgery, its principles and practice. Philadelphia: WB Saunders, 1909:1906–1921 9. Quinn JH. Lateral coronoid approach for intraoral reduction of fractures of the zygomatic arch. J Oral Surg 1977;35:321 10. Guilles HD, Kilner TP, Stone D. Fractures of the malar-zygoma compound with a description of a new x-ray position. Br J Surg 1927;14:651 11. Comert E, Comert A, Aysun Uz, et al. Anatomic basis of percutaneous Kirschner wire insertion in zygoma fractures. J Craniofac Surg 2011;22:1483–1485 12. Muto T, Yahara N, Hashiba T. Reduction and fixation of zygomatic complex fractures using a simple external device. Asian J Oral Maxillofac Surg 2010;22:205–207 13. Honig JF, Merten HA. Classification system and treatment of zygomatic arch fractures in the clinical setting. J Craniofac Surg 2004;15:986 14. Ozyazgan I, Gunay GK, Eskitascioglu T, et al. A new proposal of classification of zygomatic arch fractures. J Oral Maxillofac Surg 2007;65:462 15. Yamamoto K, Murakami K, Sugiura T, et al. Clinical analysis of isolated zygomatic arch fractures. J Oral Maxillofac Surg 2007;65:457 16. Turan A, Kul Z, Haspolay Y, et al. Use of tracheal tube in isolated fractures of the zygomatic arch. Plast Reconstr Surg 2004;114:1005–1006 17. Park BY, Song SY, Yun IS, et al. First percutaneous reduction and next external suspension with Steinmann pin and Kirschner wire of isolated zygomatic fractures. J Craniofac Surg 2010;21:1060–1065 18. Ramanoojam S, Gadre P, Shah S, et al. Assessment of the adequacy of closed reduction in fractures of the zygomatic arch using C-arm image intensifier. J Craniofac Surg 2011;22:1383–1386
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
Zygomatic Arch Fracture: A New Classification and Treatment Algorithm With Epidemiologic Analysis Jiye Kim, MD,* Seungchan Kim, MD,* Seum Chung, MD, PhD,† and Yoon Kyu Chung, MD, PhD* Abstract: Determining the optimal method for zygoma fracture reduction is a common challenge. Numerous methods for treating zygomatic arch fractures have been suggested. However, a substantial gap exists between suggested treatment strategies and real-world practice. A general consensus of classification and treatment guidelines for zygomatic arch reduction has not yet been established. We reviewed our cases and propose a new classification of zygomatic arch fracture and a treatment algorithm for successful reduction based on the injury vectors. Key Words: Zygomatic arch, classification (J Craniofac Surg 2014;25: 1389–1392)
T
he zygoma is the most prominent portion of the face, and its injury is common in facial trauma. Isolated arch fractures comprise 10% of all zygoma fractures1 and 5% of all facial bone fractures.2 Almost all simple zygomatic arch fractures are treated in a closed fashion with a Dingman elevator using the Gillies approach or the Keen approach. To reduce the zygomatic arch completely, comprehension about the vector of fracture is needed. Some reports recommend open reduction of the zygomatic arch in complex-type fractures; however, there are many difficulties and risks associated with an open approach. The coronal approach carries the risk of having a long scar, scalp numbness, alopecia, or temporal hollowing in addition to the usual risks associated with a long operation time.3 In this report, we reviewed our zygomatic arch fracture cases and propose a new classification and corresponding treatment algorithm. In addition, through analysis of trauma causes and associated factors, we promote an understanding about its treatment and prevention.
METHODS Data Collection We retrospectively reviewed 424 patient’s zygomatic arch views and facial bone computed tomographies, who visited the Wonju Severance Christian Hospital from 2007 to 2010 with zygomaticomaxillary fractures. Of the 424 patients, 113 were purely maxillary fracture patients without zygomatic arch fracture. Exempting From the *Department of Plastic and Reconstructive Surgery, Wonju College of Medicine, Yonsei University, Wonju, Korea; and †National Health Insurance Corporation Ilsan Hospital, Ilsan, Korea. Received December 10, 2013. Accepted for publication February 8, 2014. Address correspondence and reprint requests to Dr. Yoon-kyu Chung, Department of Plastic and Reconstructive Surgery, Wonju College of Medicine, Yonsei University, Wonju Christian Hospital 162 Ilsandong, Wonju, Korea 220-701; E-mail: [email protected] The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000864
the pure maxillary fracture cases, 311 zygomatic arch or zygomaticomaxillary fractures were analyzed. We collected the patient’s data by clinical chart review. Patient’s data include age, sex, and cause of trauma. Statistical analysis was done by Chi-squared analysis.
Fracture Subtype Isolated zygomatic arch fractures were classified as type 1. Zygomaticomaxillary complex fractures involving zygomatic arch fractures were categorized as types 2 or 3. Type 2 fractures are defined by the mechanistic application of force in 1 direction; and type 3, by the application of 2 directions of force. Comminuted zygomatic arch fractures were classified as type 4. Each fracture type is further classified by approximately 1 to 3 subtypes (Figs. 1, 2).
Type 1: Isolated Zygomatic Arch Fracture Type 1A is a typical M-shaped zygomatic arch fracture. It is the simplest type of fracture and easily corrected by the Gillies or Keen procedure (Fig. 1A). Type 1B is a zygomatic arch fracture that developed in the posterior portion. To reduce the fractured segment, a Dingman elevator is inserted into the deep surface to reach the posterior segments. Adequate pointed lever action by the Dingman elevator is important in this subtype of fracture (Fig. 1B). Type 1C is the most unstable fracture type in purely zygomatic arch fractures. Inadequate reduction usually results in a floating fractured segment. If the Gillies or Keen approach is used, accurate targeting insertion of the Dingman elevator under the fractured segment is important. If the fracture is unstable after closed reduction with the Dingman elevator, then we insert the 0.16-mm Kirschner wire (K-wire) into the floating fractured segments with C-arm, and the fracture is reduced by a K-wire (Fig. 1C).
Type 2: Zygomaticomaxillary Fracture (Unidirectional) A type 2 fracture is simply reduced with a K-wire that is inserted on the malar prominence. Type 2A is the same as the malar fracture classification type 5 of Knight and North. The fractured zygomatic body is laterally rotated, and the zygomatic arch is fractured like the M shape. This type of fracture is corrected easily by K-wire reduction with internal rotation of the fracture (Fig. 1D). Maxillary fracture was fixed with internal fixation device through oral incision in conventional method. Type 2B corresponds to Knight and North classification of type 4. The medially rotated zygoma body makes an arch fracture in the “blow-out” shape. This is also corrected by K-wire insertion on the malar body and outward rotation movement with a K-wire (Fig. 1E). Type 2 fracture combines with maxillary fracture, and the lateral buttress fracture line was fixated with internal plate through oral incision as the conventional method. After complete fixation, the inserted K-wire was removed.
Type 3: Zygomaticomaxillary Fracture (Bidirectional) A 3A fracture is similar to the 2A subtype; however, the anterior part of the zygomatic arch is impacted under the posterior zygomatic arch segment. Because type 3 fractures develop from
The Journal of Craniofacial Surgery • Volume 25, Number 4, July 2014
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The Journal of Craniofacial Surgery • Volume 25, Number 4, July 2014
FIGURE 3. Distribution of fracture subtypes.
Type 3B is also laterally rotated; however, the fracture location of the zygomatic arch is more posterior than for type 2A. With simple medial rotation force, the posterior fractured segment is usually collapsed and becomes an unstable fracture. With rotation force by the K-wire, the posterior fracture segment must be concurrently elevated with Dingman elevator (Fig. 1G). As type 2 fracture, type 3 fracture combines with maxillary fracture, and the lateral buttress fracture line was fixated with internal plate through oral incision as the conventional method.
Type 4: Comminuted Fracture FIGURE 1. Zygomatic arch fracture classification and its reduction (blue dotted arrow, trauma force; red arrow, rotation vector; green line, inserted K-wire on zygoma segment; blue device, Dingman elevator). A, Subtype 1A. B, Subtype 1B. C, Subtype 1C. D, Subtype 2A. E, Subtype 2B. F, Subtype 3A. G, Subtype 3B. H, Subtype 4.
2 directions of force, in type 3 reductions, another assisted reduction force is needed apart from the K-wire on the malar prominence. In the 3A subtype reduction, first, the malar body is elevated anteriorly by an inserted K-wire on the malar body to escape the weight of the posterior zygomatic arch segment. With this anterior reduction force, a second medial rotation force is applied by another inserted K-wire (Fig. 1F).
FIGURE 2. A comparison of preoperative and postoperative zygomatic arch views according to zygomatic arch classification. A, Subtype 1A. B, Subtype 1B. C, Subtype 1C. D, Subtype 2A. E, Subtype 2B. F, Subtype 3A. G, Subtype 3B. H, Subtype 4.
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A type 4 fracture is a comminuted-type fracture. In our cases, all of these types of fractures were open fractures. Through the open wound, we were able to easily approach the fractured segments and treat the fractured bone with plating (Fig. 1H).
RESULTS Isolated zygomatic arch fractures (type 1) comprised 21% (67cases) of the total zygomaticomaxillary fractures (311 cases). Among the subtype groups, 2B fractures were the most common (123 cases, 39% in the total group) (Fig. 3). Of the isolated fractures, type 1A was the most common (44 cases, 65.67% in the isolated fracture group). During the 5 years of collected data, the incidence of zygoma fracture cases gradually increased (Fig. 4). Of the 311 patients, 265 were men, and 46 were women. The largest age group for zygomatic arch fracture incidence was 50 to 59 years (70 patients, 22.5%) (Fig. 5). The second largest group was 40 to 49 years old (68 patients, 21.9%), and the third largest group was 20 to 29 years old (63 patients, 20.3%). In our cases, there were pediatric fractures in those younger than 10 years. For patients in their 40s and 50s, the type 2B fractures were the most common; however, type 2A fractures were more frequent for patients in their 20s. For patients in their 30s, the frequency of type 2A fractures was same as for type 2B. As a result, in the younger age group, 2A subtype was dominant, and in the older age group,
FIGURE 4. Trend of zygomatic arch fracture incidence during a 5-year period.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 25, Number 4, July 2014
Zygomatic Arch Fracture Classification
TABLE 2. Cause of Trauma and Association With Drunken Status Cause of Trauma Motor vehicular accident
FIGURE 5. Age distribution in zygoma fractures.
2B subtype was more frequent. Among all age groups, there was a statistically significant difference in fracture subtype (P = 0.4745) (Table 1). The cause of trauma varied (Table 2). The most common cause was a fall injury. Whether occurring in the outdoors or indoor, zygomatic arch fractures easily develop when a patient loses their feet and collides with something such as a wash basin or a rock, and 23.8% of fall injuries occurred while being drunk. The second most common cause was a traffic accident. Although we expected types 3 and 4 fractures to develop in a high-energy injury such as a motor vehicular accident or a fall injury, there was no statistical significance between the fracture subtype and the cause of trauma. Among associated sports, soccer was most commonly associated with zygomatic fractures.
DISCUSSION The zygoma is the most prominent element of the midfacial bone and is susceptible to local injury. Among midfacial fractures, a zygoma fracture is the second most common injury after nasal bone fracture.4 If not adequately treated, these fractures can result in significant cosmetic deformities and a palpable bony step. If the degree of zygomatic arch deformity is severe, mouth opening function is disturbed, and trismus can even develop. The fundamental method of zygomatic arch reduction is the open approach. With bicoronal incisions, the zygomatic arches are wholly visualized, making accurate reduction possible. Although there are many advantages to the open approach for skeletons, many complications should be considered relating to soft tissue covering the facial bones. With the coronal approach, soft tissue sequelae such as scalp numbness, alopecia, temporal hollowness, and facial nerve injury must be considered.5–7 To avoid these risks from open approach, Keen8 developed the transoral approach to zygomatic arch reduction, and Quinn9 recommended the method of the modified Keen transoral approach. Guilles et al10 used a temporal approach to TABLE 1. Age Groups and Fracture Subtype Distribution Age Group
Drunken Cases
%
61 43 19 6 63 34 33 25 25 14 6 2 2 1 2
3 8 1 1 15
19.6 13.8 6.1 1.9 20.3 10.9 10.6 8.0 7.7
1
0.9
the zygomatic arch, and Gillies approach is the most widely used method today. Since then, numerous closed reduction methods have been suggested to reduce the zygomatic arch involving the methods with a hook,10 mosquito,6 K-wire,3,11,18 and even external suspensory devices.12 However, these efforts are concentrated on the development of a new method of closed reduction. A generally accepted classification and treatment guideline for zygomatic arch reduction has not yet been established. Although some authors suggested simple classification of zygomatic arch, their numbers of cases were insufficient to prove the classification; they simply proposed the closed approach in stable fracture and open approach in unstable fracture.13–15 In this article, we propose a practical algorithm for treating the variable cases of zygomatic arch. We usually use the Gillies procedure to treat type 1 zygomatic arch fractures. In previous articles, pure zygomatic arch fractures account for 5% to 10% of all zygoma fractures.1,7,16 In our data, pure-type zygomatic arch fractures (type 1) comprise 21% of all zygomaticomaxillary fractures. Almost all cases of type 1 fractures were reduced stably with the Gillies approach. However, some unstable fractures could be observed in the subtype 1C fractures. For those cases, we modified Park et al's17 method of external suspension with a K-wire. We inserted the K-wire with C-arm into the unstable fractured segment, and the reduction was done with that K-wire. Another K-wire was inserted into the stable portion of the zygoma to sustain the previously inserted K-wire into the unstable segment. Two K-wires are fixated to each other (Fig. 6), and this temporary fixation is removed 3 weeks after the operation. Type 2 fractures are easily corrected with a K-wire inserted on the malar body. With internal fixation on the lateral buttress and inferior or lateral orbital rim, the zygomatic arch fracture is stably maintained postoperatively.
Fracture Type
Frequency
1A
1B
1C
2A
2B
3A
3B
4
Total
10s
4 8 5 7 11 5 4
0 0 3 2 5 2 1
0 1 0 3 3 2 1
3 26 14 12 15 5 6
15 24 14 23 28 12 4
0 2 1 5 3 5 4
0 3 1 7 2 0 2
0 0 0 1 3 0 1
21 63 37 68 70 30 22
20s 30s 40s 50s 60s 70s
Motorcycle accident Bicycle accident Farm machine accident Slip down injury Fall down injury Assault Industrial accident Sports Soccer Baseball Golf Snowboarding Jogging Miscellaneous
No. Cases
FIGURE 6. Park method of external suspension with a K-wire. A, K-wire for the reduction of fracture segment. B, K-wire for the suspension of A.
P = 0.4745.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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The Journal of Craniofacial Surgery • Volume 25, Number 4, July 2014
Kim et al
Type 3 fractures tend to be more difficult to reduce than type 2 fractures. Two or more different vectors are involved in generating this type of fracture, and with only 1 target reduction vector, it can be difficult to obtain an adequate correction of the zygomatic arch. Subtype 3A fractures need 2 directions of traction force to treat the fracture. Subtype 3B fractures need another pushing force under the posterior fracture segment with the Keen approach using a Dingman elevator. In type 4 fractures, the open approach is necessarily needed. However, type 4 fractures are usually high-energy fractures with accompanying soft tissue injury on the zygomatic arch. In our cases, all type 4 fractures were open fractures with an approach through the open wound where internal fixation could be applied. In our 5-year analysis, the frequency of zygomatic arch cases steadily increased. Although efforts have been made to reduce motor vehicular accidents and industrial accidents, the number of zygomatic arch fractures has increased in Korea. Peak incidence is observed in the 50th and 40th decades followed by the 20th decade. Unlike most trauma-related injuries occurring in the 20th and 30th decades of life relating to sports and industrial causes, the cause of zygoma fractures relating to fall injuries or traffic accidents can occur at any age. Contrary to our expectations, the contribution from alcohol drinking was small in motor vehicular accidents and assault. Instead, it contributed in large part to fall injuries. The rate of zygoma fractures in men was quadruple to that of women. Men may be more susceptible to local trauma because of an association with individual drinking habits and harsh occupational activity. In our classification, types 1 and 2 fractures occur by lowenergy mechanisms, and types 3 and 4 occur by high-energy mechanisms. We anticipate high-energy events such as motor vehicular accidents or falls to frequently generate type 3 or 4 injuries. However, in statistical analysis, there was no significant association between trauma cause and fracture type. Among the sports, soccer most commonly resulted in zygoma injuries, perhaps because soccer had more frequent physical fights than other sports.
CONCLUSIONS Except for comminuted zygomatic arch fractures, most zygomatic arch fractures were reduced and sustained with a closed approach. Many articles referred variable methods to reduce the zygomatic arch in a closed approach; however, general treatment guideline according to practical classification was not yet established. With a well-organized classification system and a cautious approach to the zygomatic arch fracture, a good result can be obtained without the need for an open reduction.
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© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
