Efficacy of Locking Miniplates in Managing Mandibular Fractures without Intermaxillary Fixation.

Background: In maxillofacial trauma, the most commonly encountered are mandibular fractures requiring treatment. Managing these fractures with rigid fixation abolish the intermaxillary fixation (IMF) requirement with reduction and early return to function. Aims: The present trial was carried out to assess clinically the effectiveness of new locking bone plate screw system postsurgically in mandibular fracture cases without IMF. Materials and
Methods: In 18 subjects, the fracture site was exposed, fracture segments were reduced and approximated keeping the occlusal relationship is desirable using locking 2 mm mini plates and screws without IMF. The subjects were followed every week for initial 4 weeks followed by evaluation for up to 6 months every month to assess clinical and radiographic healing and the results were formulated.
Results: Road traffic accident was the cause in 10 subjects (55.5%), followed by assault in 22.2% (n = 4) subjects, and fall from height in 16.6% (n = 3) subjects. Parasymphysis was involved in 44.4% (n = 8), followed by symphysis in 11.1% (n = 2) subjects. A minor complication of wound dehiscence was seen in 5.5% (n = 1) subjects that were managed conservatively and a major complication of infection was also seen in 1 subject that required removal of the plate at 4 weeks of follow-up. Following plate removal, IMF was done for that subject. All other sites were healed uneventfully. Primary healing in bone was seen in 94.4% (n = 17) subjects and it was not seen in the case with infection.
Conclusion: Within the limitations, the present study concluded that the locking miniplate system is highly effective and reliable in treating mandibular fractures with acceptable results and a very low postoperative complications rate. Copyright:

INTRODUCTION

For maxillofacial trauma leading to the fractures, the management strategies have advanced from basic bandaging to splints and wirings, leading to pins used extra-orally, transosseous wiring for semi-rigid fixation, to most latest rigid fixation using compression plates and miniplates. In maxillofacial trauma, the most commonly encountered are mandibular fractures requiring treatment. Managing these fractures with rigid fixation abolish the intermaxillary fixation (IMF) requirement with reduction and early return to function.[1]

With large surgeons following rigid fixation eliminating the need for IMF for managing mandibular fractures, the various plating systems have been evolved and studied. In fractures and osteotomies, various plating systems of bone have been introduced. Recently, various alterations including locking screw and/or plates as well as reconstruction plates have been adapted in maxillofacial trauma management and have proved advantageous over earlier used techniques.[2]

A shortcoming of the plates used conventionally for managing trauma and fractures of the maxillofacial region was their accurate adaptation to immobilize the fracture segments to not alter the occlusal relationship and bone alignments. With advances in research and technologies, various modifications for plates were done in terms of their shape, screw system, size, plate biomechanics, and/or number.[3] One such advancement is the locking system in the bone plates used conventionally. In the new locking system, the holes are made in the plate to fit screws that lock to plate by threads in screw allowing plates to act as fixators internally to establish the stability by locking.[4]

This locking design offers the advantage of not worry to maintain a close adaptation between the plate and the bone by making close contact between two easy with lesser changes in occlusal relationships and bone segments on tightening the screws. Furthermore, locking plates have minimal on no effect on the existing bone anatomy compared to the conventional plate which pushes the bone surfaces towards the cortical alveolar bone.[5] Locking plate and screw system do not allow loosening of screw plate system easily from the bone even if the screws are placed at the line of fracture. Various inflammatory reactions and related complications are reported in the literature after screw loosening from the plate, these inflammatory reactions are also decreased with the usage of a locking screw plate system. These systems are being reported as efficacious over other systems in the literature.[6] The present trial was carried out to assess clinically the effectiveness of new locking bone plate screw system postsurgically in mandibular fracture cases without IMF.

MATERIALS AND METHODS

The present trial was carried out to assess clinically the effectiveness of new locking bone plate screw system postsurgically in mandibular fracture cases without IMF. The present study was carried out on 18 subjects visiting the Department of Oral and maxillofacial surgery with mandibular fractures that were either minimally displaced or undisplaced. The 18 study subjects included both males and females within the age group of 20–52 years with a mean age of 34.7 years. The subjects were selected randomly for the study and were treated with titanium miniplates having a locking system.

To be included in the study, the subjects should have either minimally displaced or undisplaced fractures affecting either parasymphysis, symphysis, angle, and/or body of the mandible, should be 18 years of age or more, and those who gave the consent. The study proceeded after obtaining ethical clearance from the committee. The subjects with severely displaced fractures, not in state to give informed consent, coronoid fractures, condylar fractures, comminuted fractures, pregnant and lactating females, subjects with medical history, infection at the fracture site, and/or subjects on medication were excluded from the study.

Following examination both radiographically and clinically, the fracture site has been exposed either extra orally or intraorally. The fracture segments were reduced and approximated keeping the occlusal relationship is desirable using locking 2 mm mini plates and screws. No IMF was done. Analgesics and antibiotics were prescribed for 5 days postoperatively. Postoperative instructions regarding oral hygiene and postsurgical care were demonstrated clearly to the patients and caretakers. The subjects were followed every week for initial 4 weeks followed by evaluation for up to 6 months every month to assess clinical and radiographic healing and the results were formulated.

The collected data were subjected to statistical evaluation incorporating ANOVA using IBM SPSS software 2012; version 21.0, Armonk, NY, USA, and the results were formulated keeping the level of significance at P < 0.0001.

RESULTS

The study included 18 subjects having both males and females within the age group of 20–52 years with a mean age of 34.7 years. The demographic characteristics of the study subjects are listed in Table 1. Among 18 subjects there were 94.44% males (n = 17) and 5.55% (n = 1) females. 11.11% (n = 2) subjects had a previous history of trauma corrected with no complications and uneventfully postoperatively, whereas 88.88% (n = 16) subjects had trauma and mandibular fracture for the first time. The maximum trauma cases were within the age group of 25–35 years with 11 (61.11%) subjects.

Table 1

Demographic characteristics of the study subjects

Parameter	Percentage (n)
Age range (years)	18-52
Mean age (years)	34.7
Sex
Male	94.44 (17)
Female	5.55 (1)
Previous history of trauma
Positive	11.11 (2)
Negative	88.88 (16)

On assessing the cause of the fracture in the study subjects, it was seen that road traffic accident was the most commonly seen etiological factor for the mandibular fracture with 10 subjects (55.5%). This was followed by an assault which was the etiology of fracture in 22.2% (n = 4) subjects, followed by a fall from the height which was documented in 16.6% (n = 3) subjects, and an accidental fall in 5.5% (n = 1) subject as described in Table 2.

Table 2

Etiology of mandibular fractures in the study subjects

Etiology	Percentage (n)
Road traffic accident	55.5 (10)
Assault	22.2 (4)
Fall from height	16.6 (3)
Sports injury	-
Accidental fall	5.55 (1)
Others	-

The study also evaluated the fracture site of the mandible and the results are summarized in Table 3. It was seen that the maximum fractured site was parasymphysis with 44.4% (n = 8) involvement followed by symphysis in 11.1% (n = 2) subjects. The mandibular body and angle were each involved in 22.2% (n = 4) subjects. Among 18 fractures, 66.6% (n = 12) fractures were displaced minimally and 33.3% (n = 6) fractures were displaced. 72.2%% (n = 13) teeth were retained in the fracture site and 27.7% (n = 5) were extracted only when they were fractured.

Table 3

Characteristics of the fracture sites in the study subjects

Fracture site characteristics	Percentage (n)
Site involved
Parasymphysis	44.4 (8)
Symphysis	11.1 (2)
Body	22.2 (4)
Angle	22.2 (4)
Displacement
Minimally displaced	66.6 (12)
Undisplaced	33.3 (6)
Teeth in fracture line
Retained	72.2 (13)
Extracted	27.7 (5)

On evaluating the postoperative results, the parameters are described in Table 4. An intraoral approach was used in 72.2% (n = 13), a combined approach was used in 22.2% (n = 4), and an extraoral laceration was used as an approach in only 1 subject (5.5%). The mean time of surgery was 1–6 days. The subjects were followed every week for initial 4 weeks followed by evaluation for up to 6 months every month to assess clinical and radiographic healing and the results were formulated. A minor complication of wound dehiscence was seen in 5.5% (n = 1) subjects that were managed conservatively and a major complication of infection was also seen in 1 subject that required removal of the plate at 4 weeks of follow-up. Following plate removal, IMF was done for that subject. All other sites were healed uneventfully. Primary healing in bone was seen in 94.4% (n = 17) subjects and it was not seen in the case with infection.

Table 4

Treatment characteristics of the mandibular fractures in the present study

Treatment characteristics	Percentage (n)
Treatment approach
Intraoral	72.2 (13)
Intraoral and extraoral	22.2 (4)
Extraoral	5.5 (1)
Complications
Minor (wound dehiscence)	5.5 (1)
Major (infection)	5.5 (1)
Healing
Primary healing	94.4 (17)
Delayed healing	5.5 (1)

DISCUSSION

The present study utilized the newly developed locking system of bone plates/screws. The use of this system has been proved advantageous by the previous report of Feller et al. in 2003 where authors mentioned no need for close bone adaptation with better maintenance of occlusal relationship and segment adaptation. With great stability, less loosening, this system also causes no damage to the underlying bone was seen with screw plate locking system compared to other plates as described by Ellis and Graham[7] in 2002 and Bolourian[8] in 2002.

The present study evaluated the efficacy of titanium locking plate/screws in treating the mandibular fracture without the IMF where 18 subjects with 27 fractures were assessed following open reduction and internal fixation, and the study reported that locking screws/plate system is a highly effective method for treating such cases. These results were in agreement with the findings of Kirkpatrick et al.[9] in 2003 and Chritah et al.[10] in 2005 where authors found locking plate/screw system reliable in treating mandibular fractures.

The study also evaluated the fracture site of the mandible. It was seen that the maximum fractured site was parasymphysis with 44.4% (n = 8) involvement followed by symphysis in 11.1% (n = 2) subjects. The mandibular body and angle were each involved in 22.2% (n = 4) subjects. Among 18 fractures, 66.6% (n = 12) fractures were displaced minimally and 33.3% (n = 6) fractures were displaced. 72.2%% (n = 13) teeth were retained in the fracture site and 27.7% (n = 5) were extracted only when they were fractured. These results also correlated with the studies of Collins et al.[11] in 2004 and Mukerji et al.[12] in 2006 where similar findings in terms of fracture-related parameters were reported by the authors.

The subjects were followed every week for initial 4 weeks followed by evaluation for up to 6 months every month to assess clinical and radiographic healing and the results were formulated. A minor complication of wound dehiscence was seen in 5.5% (n = 1) of subjects that were managed conservatively and a major complication of infection was also seen in 1 subject that required removal of the plate at 4 weeks of follow-up. Primary healing in bone was seen in 94.4% (n = 17) subjects and it was not seen in the case with infection. These findings were following the findings of Aframian-Farnad et al.[13] in 2002 and Alpert et al.[14] in 2003 where similar complication rates were founded by the authors in their findings.

CONCLUSION

Within the limitations, the present study concluded that the locking miniplate system is highly effective and reliable in treating mandibular fractures with acceptable results and a very low postoperative complications rate. However, the study had few limitations including small sample size, short monitoring period, geographical area bias, and single institutional study. Hence, further prospective and longitudinal trials with a longer monitoring period and larger sample size are required to reach a definitive conclusion.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.