Abstract
Background and Aim:
Three-dimensional (3-D) miniplates have shown better results in the treatment of mandibular fractures but it is difficult in the treatment of mandibular parasymphysis fracture that involves mental foramen or in close proximity. To overcome this, we have modified the 3-D miniplate with a single vertical bar and assessed its efficacy in the mandibular body or parasymphysis fracture.
Methodology:
A clinical prospective study was carried out in 20 patients with mandibular body or parasymphysis fractures involving or near mental foramen and treated with a modified 3D miniplate under general anesthesia (GA). The parameters assessed were state of occlusion, neurosensory disturbances, visual analog scale (VAS) score for pain, infection pus, mobility of fracture segment, operating time for adaptation and fixation of the plate, surgeon’s opinion on ease of adaptability of the plate, and union of fracture site radiologically. The patients were assessed pre-operatively, first, second, eighth, and 16th week postoperatively.
Results:
The data obtained was analyzed using McNemar’s test and paired t-test. Occlusal derangement was corrected and was statistically significant (P < 0.5). The mean operating time for adaptation and fixation was 8.45 min. Temporary paresthesia of the mental nerve was very minimal (P < 0.5). The rate of infection was significantly less. There was no incidence of mobility or fracture of the modified 3D miniplate.
Conclusion:
The modified 3D miniplate was efficient in restoring the occlusion, reducing the incidence of temporary paresthesia of mental nerve, and was easy to adapt which aided in bringing down the treatment duration in the management of mandibular body or parasymphysis fracture.
Keywords: Infection, mandibular fracture, mental nerve, paresthesia, three-dimensional
INTRODUCTION
A maxillofacial surgeon treats various facial injuries but mandibular fractures top that list. About 96% of mandibular fractures result from interpersonal violence, motor vehicle accidents, and self-fall with peak age of incidence ranging from 20 to 50 years of age.[1] Motorcycle accidents resulted in a larger number of symphyseal fractures (29.7%) and fewer condylar fractures (23.4%) than did automobile accidents. Body, angle, and alveolar fractures occurred at frequencies similar to that of automobile accidents.[2]
The aim of the mandibular fracture treatment is the restoration of anatomical form and function, with particular care to establish the occlusion.[3] There have been tremendous innovations in the treatment modalities and the armamentarium used in facial fracture management. A three-dimensional (3-D) plate with a quadrangular design formed by joining two miniplates with interconnecting crossbars was developed by Farmand.[4] However, the main drawback of the conventional 3D plate is its inability to adapt/use in the body or parasymphysis region due to the presence of mental nerve. The conventional 3D plates are rectangular with two horizontal bars connected by two vertical bars. To overcome this disadvantage of 3D plates, we felt a need to modify the 3D plate by removing the anterior vertical bar to adapt it easily around the mental nerve in the body or parasymphysis fracture. The study aimed to evaluate the role of a modified 3D miniplate in the mandibular body or parasymphysis fracture involving mental foramen. The role of modified 3D miniplates was evaluated with the following objectives: occlusion, neurosensory disturbances, pain, infection, mobility of the fractured segment at the plated site—present or absent, operating time, surgeon’s opinion regarding the ease of adaptability/use, status of the plate, and malunion.
METHODOLOGY
About 20 patients with mandibular body or parasymphysis fractures involving mental foramen who reported to the Department of Oral and Maxillofacial Surgery, and Accident and Emergency Section, were selected using the following inclusion and exclusion criteria. All of our patients had unilateral fractures. Ethical Committee Ref no. IECKVGDCH/20/2017-18 Dated on 16.11.2017.
Inclusion criteria
Isolated body/parasymphysis fracture unilateral involving the mental foramen or near mental nerve.
Bilateral body/parasymphysis fracture involving the mental foramen or near mental nerve.
Multiple mandibular fractures or pan facial fractures with at least one body/parasymphysis fracture involving the mental foramen or near mental nerve.
Patients willing to participate in the study
Patients who are fit to undergo surgery under general anesthesia (GA).
Exclusion criteria
Patients not willing to participate in the study.
Medically compromised patients unfit for surgery
Edentulous mandible
Pediatric patients.
Malunited or non-united mandibular body/parasymphysis fracture.
Materials used for the study
Modified three-dimensional miniplates (stainless steel) [Refer Figure 1]. Rectangular four-holed dimensional miniplate with one vertical arm.
Figure 1.
Modified 3D mini-plate designed by connecting 1 cm
Dimensions: Length of horizontal arm-2.5 cm, length of vertical arm-1 cm, width-2 mm, eight-holed with gap. Plate size-1.5 mm thickness.
Monocoritcal screws-8 mm.
Bone plating kit.
PROCEDURE
Pre-operative preparation of patient
Routine blood investigations, computed tomography scans, and orthopantomograph (OPG).
V antibiotics and analgesics.
Written consent was obtained from all the patients.
Asepsis of the operative site and operative field was ensured.
Surgical procedure
The procedure was performed under GA with nasotracheal intubation and injection of local anesthetic solution (2% lignocaine with adrenaline 1:80,000) in the operating site by the same surgeon.
The fracture site was exposed (14 patients by extraoral approach and 6 patients by intraoral approach). The extraoral approach was used in the case of previously existing extraoral lacerations, accompanying other facial fractures, or in the case of comminuted fractures.
Fracture fragments were reduced.
Modified three-dimensional miniplate fixation was done [Refer Figure 2a-f].
Figure 2.
Mandibular parasymphysis fracture management using modified 3D miniplate by Extraoral approach. (a) Sublingual hematoma following mandibular parasymphysis on right side, (b) CT scan revealing fracture of mandibular parasymphysis, (c) Pre-operative OPG revealing fracture of mandibular parasymphsis on right side, (d) Fracture site exposed extraorally, fracture line running through the mental nerve, (e) Modified 3D miniplate fixed after fracture reduction, and (f) Post-operative OPG, showing Modified 3D plate in mandibular parasymphysis fracture
Closure of the wound was accomplished with 3-O Vicryl.
Postoperative management of the patient
IV antibiotics and analgesics were administered.
A liquid and semisolid diet was advised.
Rehabilitation and follow-up
Patients were recalled at the first week, second week, eighth week, and 16th week for assessing and recording the following clinical and radiographic parameters.
POSTOPERATIVE ASSESSMENT
Clinical parameters
State of occlusion: The occlusion was considered satisfactory when the patient can occlude on both sides and perform normal function. Occlusal derangement was graded as:
Mild: slight or no derangement of occlusion, no need for intervention.
Moderate: occlusion deranged and the function is affected and needs correction by non-surgical means (elastics).
Severe: gross occlusal derangement with a functional disability that needs reoperation.[5]
The state of occlusion was evaluated pre-operatively and postoperatively on the first week, second week, eighth week, and 16th week.
Neurosensory disturbances: Paresthesia was assessed using a pinprick test.[6] A sharp dental probe was applied onto the skin in a quick pricking movement on the affected part in the region innervated by the mental nerve. The pain perception of the patients was assessed and recorded as follows:
Paresthesia present—when pain was not perceived by the patient.
Paresthesia absent—when pain was perceived by the patient.
Neurological disturbances were evaluated pre-operatively and postoperatively on the first week, second week, eighth week, and 16th week.
Pain was assessed using a visual analog scale (VAS) during the first week, second week, eighth week, and 16th week of the postoperative period.
Infection—Presence or absence of infection was assessed clinically and radiographically during the first week, second week, eighth week, and 16th week of postoperative period.
Mobility of the fractured segment at the plated site—present or absent was assessed clinically during the first week, second week, eighth week, and 16th week of postoperative period.
Operating time was recorded from the time of adaption to the fixation of the plate in minutes.
The surgeon’s opinion regarding the ease of adaptability/use (easy or difficult) was obtained.
Radiographic parameters
Plate stability—The dimensional stability of the three-dimensional miniplate was assessed during the first week, eighth week, and 16th week of postoperative period using OPG for the presence of any break/fracture and radiolucency present around the plate.
Malunion was assessed during the first week, second week, eighth week, and 16th week of the postoperative period using OPG.
RESULTS
The data was assessed statistically using McNemar’s test and paired t-test.
The occlusion was considered satisfactory when the patient could occlude on both sides and perform normal function. The difference was found to be statistically significant (P value: 0.001) in McNemar’s test. Occlusal derangement was corrected in all the patients by the eighth postoperative week [Refer Figure 3].
Figure 3.
State of occlusion
Pre-operative paresthesia of the mental nerve was present in eight patients (40%). In the second postoperative week, only two (10%) patients had paresthesia and had completely resolved by the eighth postoperative week. Temporary neurological deficit of mental nerve was very minimal and was statistically analyzed using McNemar’s test proved to be significant (P = 0.031) [Refer Figure 4]. The pain was assessed pre-operatively and postoperatively at the first week, second week, eighth week, and 16th week using a VAS. The obtained data was analyzed using a paired t-test. VAS score showed significant results [Refer Table 1].
Figure 4.
Neurosensory disturbances
Table 1.
VAS score
| N | Mean SD | Mean difference ± SD | p-value | ||
|---|---|---|---|---|---|
| VAS Score pre-operative | 20 | 5.65 ± 1.73 | 1.7 ± 1.42 | <0.001 | |
| Pair 1 | VAS Score 1st week postoperative | 20 | 3.95 ± 1.73 | ||
| VAS Score pre-operative | 20 | 5.65 ± 1.73 | 3.55 ± 1.54 | <0.001 | |
| Pair 2 | VAS Score 2nd week postoperative | 20 | 2.1 ± 1.68 | ||
| VAS Score pre-operative | 20 | 5.65 ± 1.73 | 5.05 ± 1.73 | <0.001 | |
| Pair 3 | VAS Score 8th week postoperative | 20 | 0.6 ± 0.94 | ||
| VAS Score pre-operative | 20 | 5.65 ± 1.73 | 5.35 ± 1.76 | <0.001 | |
| Pair 4 | VAS Score 16th week postoperative | 20 | 0.3 ± 0.73 | ||
There were no signs of infection pre-operatively or at the first week, second, and eighth week postoperatively in any patients (100%) either clinically or radiographically. Pus discharge was present in two patients (10%) at the 16th postoperative week. Thus, the rate of infection with a modified 3D miniplate was significantly less. Pre-operatively, six patients in the study group had mobile fracture fragments which were reduced and fixed using modified 3-D miniplates and screws. None of the patients had mobility of the fractured segments when assessed clinically in all postoperative follow-up periods. The mean operating time for adaptation and fixation of modified 3D miniplate was 8.45 min. The surgeon’s opinion was acquired from the operating surgeon for all the cases. Adaptability and ease of use were easy for 11 cases (55%), moderately difficult in 5 cases (25%), and difficult in 4 cases (20%).
Results showed that none of the patients had a break or fracture of the modified 3D miniplate used in the fixation of parasymphysis fractures. The fractured site was inspected for the union on the eighth and 16th postoperative week using OPG. None of the patients had malunion or fibrous union or non-union.
DISCUSSION
Maxillofacial injuries have continued to interest clinicians and researchers because of the functional and cosmetic deformities that the affected individuals have to confront with. Methods for open reduction and internal fixation (ORIF) in mandibular fracture management have evolved and diversified in recent years and achieved new horizons. This present study was conducted from December 1, 2017 to June 1, 2019. About 20 patients with mandibular body or parasymphysis fractures involving or close to mental foramen were selected and treated with a modified 3D miniplate under GA. The patients were selected according to the inclusion criteria which included 20 patients out of which 17 were male patients (85%) and 3 were female patients (15%). The mean age of the patients was 34.2, the youngest being 19 years and the oldest patient was 49 years of age. The commonest cause of fracture in this study was road traffic accidents (RTA) in 18 patients (90%), 1 patient (5%) had a history of falls, and 1 patient (5%) with sport-related injuries.
Occlusal derangement was assessed pre-operatively and postoperatively. Mild occlusal derangement was present in 11 patients (55%) and 10 patients (50%) postoperatively at the first week, 4 patients postoperatively at second week. Eight patients (40%) had moderate occlusal derangement pre-operatively and only one patient had occlusal derangement in the first week postoperatively. In the eighth and 16th weeks, occlusion was normal in all the patients. For mild and moderate occlusal derangements, if the function was affected and needed correction, it was done by non-surgical methods using elastics. Similar treatment methods were adopted by Al-Tairi et al.[5] in their study.
Neurosensory disturbance of the mental nerve was evaluated both pre-operatively and postoperatively using the pinprick test in this study. Paresthesia was noted in eight patients (40%) pre-operatively, three patients (15%) in the first week and two patients (10%) in the second week postoperatively, and by the eighth and 16th weeks, none of the patients had paresthesia. Paresthesia was noted postoperatively in 11.5% of patients in a study by T. F. Renton and Wiensenfeld[7] reported sensory disturbance of the lower lip in 79 patients (24.3%) and reasons for paresthesia being dislocation, traction, or compression of the nerve. Vikas Sukhadeo Meshram et al.[6] used a two-point discrimination test, pinprick test, and light touch assessment to assess the neurosensory disturbances of the inferior alveolar nerve. Two patients in this study had paresthesia in the second week but were completely resolved in the eighth postoperative week. A study by Bede et al.[8] stated that the recovery period of paresthesia of the inferior alveolar nerve was 10 days postsurgically in 12 patients, 45 days in 4 patients, 70 days in 1 patient, 90 days in 2 patients, and 150 days in 1 patient. Neurosensory disturbances were found to be much higher in a study conducted by Iizuka T and Lindqvist,[9] pre-operatively it was 58.3% but postoperatively it was 76% at 6.2 weeks which was contradictory in our study. MW El-Anwar[10] reported that numbness was present in the early postoperative period and was relieved in all cases but persisted in one (2.5%) patient and three (7.5%) patients in the study group and control group, respectively. A study by RK Singh et al.[11] reported that pretreatment sensory disturbance was present in 46.6% of paresthesia pre-operatively, and postoperatively, 33% and 20% at 1 week, 4 weeks, and at the end of 12 weeks, respectively, in group A. Paresthesia was present in 40% of the patients pre-operatively and postoperatively, 26% and 26.6% at 4 weeks and the end of 12 weeks, respectively, in group B. Postoperative differences in nerve injury recovery could be explained based on fixation that provides more firm fixation, which helps in early nerve recovery.[11]
The pain was assessed pre-operatively and postoperatively during the first week, second week, eighth week, and 16th week using VAS. The obtained data was analyzed using a paired t-test. VAS score showed significant results with a P value of < 0.001. Pus discharge was present in two patients (10%) in the eighth postoperative week which was treated conservatively using antibiotics. None of the patients required plate removal. Thus, the rate of infection with modified 3D miniplate was significantly less. In our study, infection occurred only in the eighth postoperative week in two patients. Philip L. Maloney et al.[12] reported 3.3% of infection in their study for open reduction and internal fixation. The authors stated that the validity of the treatment protocol to immobilize compound fractures is within 72 h of injury if possible, if not infection is likely to occur; all our patients in the study were treated and operated on within 2 days post-injury and the rate of infection was also minimized. Plates and screws function to rigidly fix and prevent any movement of fracture segments by absorbing all or part of the functional load that is present at a fracture site. None of the patients in our study had mobility of the fractured segments when assessed clinically at all intervals in postoperative follow-up period.
The mean operating time for adaptation and fixation of modified 3D miniplate in our study was 8.45 min. A study by Manoj Farmand et al.[4] stated that precise adaptation of 3-D locking plates was not required and did not affect their mechanical behavior. Therefore, plate placement becomes easier and less time-consuming, and advised to bend the 3D miniplate while adapting it in the mental nerve region so that the nerve lies in the concavity in turn preventing nerve injury due to the pressure of the plate without altering the ideal line of osteosynthesis. 3-D plates were effective, provided good stability of fracture fragments, and as the adaptation is quicker, it is further cost-effective in reducing the cost of anesthesia than the locking systems.[13] The operating surgeon’s opinion was acquired on the ease of use and adaptability for all the cases. Adaptability and ease of use were easy for 11 cases (55%), moderately difficult in 5 cases (25%), and difficult in 4 cases (20%). The modified 3D miniplate used in this study was easy to adapt. The difficulty was the positioning of the mental foramen that was very near to the roots of the premolar.
Though the 3D miniplate had advantages in ease of application and assured 3D stability, the authors stated that they encountered difficulties while placing it in oblique and comminuted fractures. 3D plates needed to be bent on the lower border when needed to be placed above the mental nerve.[14] The modified 3D plate used in our study solved this issue by removing the anterior vertical bar so that it adapts easily around the mental nerve in the body or parasymphysis fracture. 3D plates were better than conventional 2 mm miniplates in parasymphysis and symphysis fracture.[15] Modified 3-D miniplate gives better stabilization than the two miniplates; one on the upper border and one on the lower border as per Champy. The modified 3-D miniplate used in this study has the additional advantage of accommodating the mental nerve through the open arm. Maybe the single plate might hold good in case of undisplaced fractures without much of occlusal deviation.
Future scope Further, our modified three-dimensional miniplates were made up of stainless steel, to reduce the cost. A better scalloping design in titanium would be easier to adapt compared to stainless steel.
CONCLUSION
The treatment of parasymphyseal mandibular fractures has evolved significantly over the past few years. We conclude that the use of a modified 3D miniplate in the management of mandibular body or parasymphysis fracture involving or near mental foramen has better advantages in fixing the fractured segments in their anatomic position, correcting the occlusal disturbances, reducing the incidence of temporary neurological deficit of mental nerve, decreasing the infection rates, and aiding in the proper union of fractured site. The time taken for adaptability and fixation was less with modified 3D miniplate in this study which further added in reducing the operating time.
Conflicts of interest
There are no conflicts of interest.
Funding Statement
Nil.
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