Incidence Of Miniplate Removal Following Its Fixation In Maxillofacial Surgery - A Retrospective Study

Keywords

Risk Factors; Miniplates; Hardware; Fixation; Oral and Maxillofacial Surgery.

Introduction

Every year nearly five thousand patients with Cranio-facial trauma are treated by open reduction and internal fixation [9, 4, 14, 11, 29, 16, 1]. Open reduction and internal fixation can be complicated by miniplate exposure, screw loosening or infection [31, 8]. Infection is usually associated with redness, inflammation and fever, which is Painful and pus may drain from the specified area [30].

Plate removal is a controversial topic in oral and maxillofacial surgery. Usually plate removal is done after completion of bone healing. Titanium plates have good tissue compatibility and it is considered to be non-carcinogenic, corrosion resistant and non toxic [13, 27]. Smoking has a strong association with hardware removal [5, 10]. In addition to rate of removal it is important to investigate the reason for the plate removal and the risk factors associated with it. Therefore the aim of this study was to investigate the incidence and reasons of removal of mini plates and to identify its risk factors.

This study states the clinical indications for removal of miniplates following their placement in trauma and orthognathic patients. It is of some importance to consider that the removal of plates is not necessarily synonymous with a failure of treatment. Union of segments may have occurred prior to removal, or may occur subsequent to removal. Miniplates may be removed for various reasons such as wound dehiscence, pain, interference with dentures and palpability. This retrospective study looks at the reasons for their removal and the possible causes for this, i.e. the determining factors of sex and age and the more specific ones of site from which the plate was removed, time lapse between injury and fixation and the time between plate insertion and its removal and the type of plate.

Materials and Methods

This was a retrospective study done in the department of oral and maxillofacial surgery, saveetha dental college, saveetha university from the records of patients available in the digital data registry. Data of patients who underwent surgeries including trauma, orthognathic surgery and cancer surgery and were later operated for plate removal from July 2019 - March 2020 were retrieved from hospital records. Got Ethical clearance from the college ethical committee and the ethical clearance number is SDC/SIHEC/2020/DIASDATA/0619-0320. A total sample of 22 patients were retrieved for the study. It included 17 trauma patients (68%), orthognathic surgery patients (13%), and cancer surgery patients (9%). Types of miniplates used in these surgical procedures were Titanium plates (81%) and Stainless steel plates (19%). Data collected were statistically analysed using SPSS version 23 and results obtained. Categorical variables were expressed in frequency and percentage; and tests of association between categorical variables were done with chi square test. A p value of <0.05 was considered as statistically significant.

Result And Discussion

In our study among 22 patients, 18 were males and 4 females. 6 patients were non smokers (29%) and othershad smoking habits (71%) (Figure 1). Infection rate and type of plate used had strong association and the results were statistically significant (p<0.05) (Figure 2). Plate removal following trauma surgery is more likely (77%) thanorthognathic surgery and cancer surgery and the results were statistically significant; Males were mostly affected (81%) (p<0.05) (Figure 3). 90% of the plates were infected and two patients wanted to remove plates for screening purposes. Out of infected plates, 80% of the plates were stainless steel and plate removal was done for those cases.

Plate removal after maxillofacial surgeries vary significantly. Studies reported [7, 21] a high rate of plate removal, but only 7% of the plates were infected. It was assumed that the reason was an active policy of plate removal.

In extreme cases where the miniplates are exposed or infected, the management depends on the duration of exposure, the amount of discomfort, screw loosening, and whether the bone is healed or stable [6, 24]. A prolonged exposure leads to contamination and infection secondary to exposure. Some authors [23, 18] reported a success rate of 83% when debridement of soft tissue was performed within 3 weeks. Infected hardware may loosen as well and it is one of the absolute indications for plate removal. In case of orthognathic surgery, the stability of miniplate after BSSO [12, 25], and incidence of titanium plate removal have been discussed [17, 3, 28].

Smoking is a powerful risk factor for plate removal and it has been confirmed in previous studies [17, 3, 19]. In our study also there is a strong association between these two variables in accordance with other studies [27].
Bioresorbable plates might be a better solution for this problem. But the previous studies [20, 1] reported 9 % complication rates for bio resorbable plates. It was concluded that these plates cause similar kinds of problems as metallic plates.

It is assumed that extensive jaw movements increase stress on miniplates. In our study we could not evaluate the relation between amount of movement and plate removal, whereas several other studies have explained them [3, 26], Many studies have described that healing is affected by increasing age, whereas in our study we could not find any association between age and plate removal.
Role of infection is a major reason for plate removal [17, 3, 15]. In our study also 90.5% of the plates were infected and caused discomfort to the patients. The treatment of plate related infections in this study was retrospectively based on medical records and we did not do bacterial sampling.
Studies have shown that titanium plates are corrosion resistant, non carcinogenic and it won't cause progressive surface deterioration. Similarly in our study we found that 80 % of the infected plates were stainless steel plates and titanium plates had better success rates.

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Conclusion

From our study it can be concluded that the reason for plate removal in most patients was related to discomfort and plate related complication. Smoking habits, gender, type of plates used have direct influence on the success of miniplate fixation. Most of the patients were relieved from discomfort after hardware removal.