Reduction of Zygomatic Bone Fracture by Two Different Treatment Protocols

By Kinza Mushtaque¹, Muhammad Shahzad¹, Safia², Salman Shams¹, Shabbir Ahmed³, Syed Ghazanfar Hassan¹

AFFLIATIONS:

1. Oral and Maxillofacial Surgery Department, Liaquat University of Medical and Health Sciences (LUMHS), Jamshoro, Sindh, Pakistan.
2. Sindh Institute of Oral Health Sciences, Jinnah Sindh Medical University Karachi, Pakistan.
3. Department of Prosthodontics, Bibi Asifa Dental College, Larkana, Sindh, Pakistan.

DOI: https://doi.org/10.36283/PJMD10-3/008

Background: Zygomatic bone, a malar bone or cheekbone usually works as eye socket. All over the world, around 15 to 20 million people are traumatized with road accidents. Over 50% of these statistics are diagnosed with zygomatic fractured bone. There are different approaches of therapy to treat zygomatic fractured bone. In this research, two approaches have been studied. The Percutaneous Hook approach is extraoral while Keen’s approach is intraoral. The objective of this study was to evaluate outcomes of two different treatment protocols (percutaneous bone hook method and Keen’s method) for reduction of zygomatic bone fracture.

Methods: This comparative analytical study conducted at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Liaquat University Hospital, Hyderabad, Pakistan. Subjects with displaced isolated zygomatic bone fracture were divided in two groups, Group A (Percutaneous Hook Method) and Group B (Keen’s Method). The data was analyzed through SPSS and p<0.05 was considered as statistically significant.

Results: Males were predominantly affected in both groups as compared to females i.e., Group A male patients were 22(73.52%) while in Group B male patients were 23(79.41%). Road traffic accidents were the most common etiological factor in both groups. There was a significant difference between the groups in diplopia, cheek flattening and mean mouth opening at postoperative 2nd, 4th and 6th week. The obtained p-value=0.01 was less than 0.05; therefore, the results were statistically significant.

Conclusion: It was observed that percutaneous hook method had better outcomes compared to Keen’s method in reducing isolated zygomatic bone fracture.

Keywords: Bone Fracture; Treatment Protocols; Zygoma.

The zygoma is roughly quadrilateral in shape with convex outer surface and concave inner surface¹. It comprises of frontal bone, temporal bone, maxilla and sphenoid bone and serves the main bridge amongst these structures. Due to its protruding malar prominence, it is vulnerable to injuries quite commonly and predisposes to be the most frequent site of midfacial fractures after fracture of nasal bones¹. This bone also has its role in facial contouring. This complex bone has the delicate as well as compact anatomy due to which cosmetic therapy needs special care when treated to improve beauty. The architecture of this bone is varied depending on the ethnicity. Moreover, the genetics and admixture are also the main elements in zygomatic bone in terms of beauty or cosmetic features². There are various reasons of this bone fracture. Some common reasons are violence, fall, sports injuries, firearm injury and automobile accidents³. Two methods of correction of this bone fracture have been discussed in this study.

The percutaneous hook method is the open reduction surgery. However, this is dependent on the nature of injury. The operation of percutaneous hook approach is carried out under anesthesia with the support of CT scan⁴. Following the incision, blunt dissection is made preventing the frontal nerve branches to avoid damage⁵. To ensure the accuracy, the region is again palpated to verify the hook site is positioned correctly⁶. Later, the incision site is stitched. After this procedure, the patient feels comfort immediately and is advised to open and close the mouth. The alignment of bone and during and after or before the opening and closing of mouth is monitored in scan noting the bone continuity. The scan monitoring is also done as post-operative treatment for at least 3 to 6 months. This approach needs the patient to stay more days in the hospital⁷. If proper care is not taken then facial paralysis may occur⁸.

With Keen’s intraoral approach the palpability risk is very low according to several studies. In addition to this, this is also highly noticed that less force is needed in the intraoral approach⁹. This approach is considered as most successful in open treatment of zygomatic fractures. The severity of operation is directly proportional to the nature of trauma. However, normally the procedure of this technique required 1cm incision mostly at the upper buccal sulcus, this area is behind the zygomatic buttress, more suitable for the introduction of curved elevator. Mostly this technique is the choice of surgeons^10,11. In this procedure, the verification is done by using digital palpation to determine the accurate adjustment of zygomatic arch region⁹.

The main purpose is to treat the isolated Zygomatic bone fracture is to restore the functional stability aesthetic appearance of malar prominence and proper healing of fracture segments, hence the aim of this study was to reduce the zygomatic bone fracture (Percutaneous hook method and Keen’s method) to maintain aesthetic, functional stability and proper healing of bony segments.

This comparative analytical study with non-probability convenience sampling method was conducted at department of Oral and Maxillofacial Surgery, LUMHS Jamshoro/Hyderabad. The Ethical Review Committee of the Liaquat University of Medical and Health Sciences had approved the study (LUMHS/REC/569). Study comprised of 68 patients. Sample size for each group was; Group A (percutaneous hook method) = 34 patients, Group B (Keen’s method) = 34 patients. Patients with displaced isolated zygomatic bone fractures were confirmed on clinically and radiologically features with age of 18 to 60 years, patients coming through emergency or out patient’s department and willing to participate in study were included. Patients with bilateral displaced fractures of zygomatic bone fractures, comminuted zygomatic fractures, and medically compromised patients were excluded from the study.

A written consent was taken from every patient or attendant of the patient. Personal details of patients including name, age, and gender were being recorded on a Performa. Selection of each patient was done by randomized number trial into two groups. The fractures were treated by reduction with transoral (Keen’s) approach and percutaneous hook method. Study was conducted after approval from ethical review committee of university. Post operatively, patients of both the group were recalled after two, four and six weeks for the assessment of the functional effects such as post-operative diplopia/eye vision, cheek flattening and mouth opening. Diplopia was assessed based on present or absent. Mouth opening was measured in millimeters by the metallic rural. Cheek flattening was assessed by clinically standing behind the top of the patient head. The data was recorded and analyzed through SPSS and p<0.05 was considered as statistically significant.

In both groups, males were predominantly affected compared to females. In Group A 27 male patients (79.41%) and Group B 25 male patients (73.52%). The frequency distribution is shown in Table 1. Road Traffic accidents were the most frequently reported cause of trauma in both groups i.e., 73.53% in Hook Technique and 76.47% in Keen’s group (Table 1).

Table 1: Frequencies of patients according to causes of injuries.

In our study the diplopia, cheek flattening and mouth opening at 2^nd, 4^th and 6^th postoperative weeks were considerably better in percutaneous hook technique group compared to Keen’s group (Table 2). In the model summary of regression analysis, the values of R, R2 and adjusted R2 (0.994, 0.988 and 0.987) indicate that the dependent variable (assessment of functional effects: percutaneous hook method: post operative: after six weeks) is supported by the independent variables to the tune of 99 percent. p value (0.01) was less than 0.05, therefore the results were statistically significant.

Table 2: Assessment of functional effects through Percutaneous Hook Method and Keen’s Method.

Our study observed that in both groups, most common etiological factor was road traffic accident and males were more affected than females. The World Health Organization (WHO) also reported that around the world, nearly one million people die every year due to zygomatic bone fracture or their post treatments like reduction of bone etc¹². The 10-15% of the death statistics is reported as the chronic sufferers. In addition to this, the WHO also mentioned that nearly 15-20 million people are injured each year with road accident as the major cause¹³. In England, the statistics revealed that in last six years, the number of suffering individuals of face fractures has increased by 30 and half of them are involved in zygomatic bone fractures¹⁴.

The WHO findings correlate with our finding that road accident is the predominant and most prevalent cause of zygomatic bone fracture. The zygoma occupies a key spot in the anterolateral aspect of the face, contributing to set the midfacial width, and to define the profile and contour of the inferior and lateral orbital borders as well as the cheek prominence¹⁵. This is in line with a number of other studies ^16-18. In Asia and other developing countries, road traffic accidents (RTA) have been thoroughly found as most common.

The peered articles suggested that 50% facial trauma cases are involved in displacement or fracture of zygomatic bone¹⁹. There are different treatment models depending on the severity of the bone damage. Many times, the skeletal healing cause the asymmetrical shape of bone and face which in many cases found challenging to fix. In many cases, patients have to undertake surgical procedures as secondary therapy in terms of effective treatment²⁰. There are several common techniques to fix the reduction and the zygomatic bone fractures. There are Keen’s, Gillies, Dingman, Buccal sulcus approach and many others. These approaches mostly are open and close reduction approach in terms of surgery for correction. We have studied the two different modes of treatment of intraoral and extraoral. They are percutaneous hook method (extraoral approach) and the Keen’s approach (intraoral approach).

The Hook approach is the open surgery^21,22. The main advantage of this approach is that the sinus problem and bone movement is not reported. The other approach of correcting zygomatic arch reported for sinus problems^{23, 24}. Keen’s approach is found more effective in treating the reduction of zygomatic bone fracture rather than any other approach including percutaneous hook method²⁵. Our study has also confirmed this trend. The patients treated through Keen’s method of therapy reported less postsurgical complication and it also takes less time for operation²⁶. In the United Kingdom (UK) and other developed countries, Keen’s approach is considered the surgeon’s first choice for reduction of zygomatic arch or fractured bone²⁷.

The Keen’s approach of reducing the zygomatic fractured bone is more suitable for achieving a better outcome. The hook method permitted defined application of traction forces across zygomatic fractures. The fractured bone portion could be pulled in the course precisely opposite to the vector of impact at the time of trauma. Moreover, road traffic accidents were reported to be the main cause of the zygomatic broken bones. In this connection, the city officials should implement the traffic rules and regulations strictly. We are certain that this will help to reduce such accidents.

The authors acknowledge the help and support of the hospital staff in completing this study.

The authors declare no conflict of interest.

The Ethical Review Committee of the Liaquat University of Medical and Health Sciences (LUMHS/REC/569) had approved the study.

At the time of data collection patients were informed. Only those patients were included who gave their consent.

SGH did the contribution in concept designing. KM and MS did data collection, data analysis, drafting and final approval of the manuscript. SS critically revised the manuscript and data analysis. S did the interpretations of the recorded data. SA revised the manuscript critically. SS did the contribution in data collection and revision.

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