|Year : 2019 | Volume
| Issue : 3 | Page : 69-73
Evaluation of efficacy of various fixation devices in management of anterior mandibular fractures: A prospective clinical study
Uday Kiran Uppada, Ramen Sinha, Prabhat Tiwari, S Vennela, Tahseen Ali Khan
Department of Oral and Maxillofacial Surgery, Sri Sai College of Dental Surgery, Hyderabad, Telangana, India
|Date of Submission||01-May-2019|
|Date of Acceptance||03-Dec-2019|
|Date of Web Publication||23-Dec-2019|
Dr. Uday Kiran Uppada
Department of Oral and Maxillofacial Surgery, Sri Sai College of Dental Surgery, Vikarabad, Hyderabad, Telangana
Source of Support: None, Conflict of Interest: None
Aim: The aim of this study was to evaluate the efficacy and reliability of fracture management in the anterior mandible using miniplates (MPs), lag screws (LSs), three-dimensional (3D) plates, and Herbert screws. Materials and Methods: The study consists of forty patients randomly divided into four groups of ten, undergoing open reduction internal fixation of anterior mandible fractures using MPs, LSs, 3D plates, or Herbert screw. All the patients were evaluated for stability of fracture fragments, duration of procedure, requirement of maxillomandibular fixation, and other associated complications. Results: The results of this study showed that each fixation device has its own merits and demerits. The rectangular plates achieved good stability, but its placement and adaptation was challenging in certain clinical scenarios when the anterior mandibular height was less, especially in females and in situations where the fracture line was in close proximity to the mental foramen. The placement of LS and Herbert screw was technique sensitive but did achieve good initial stability in addition to shortening the procedure time. The MPs were more versatile but required more operating time and hardware for the management of the anterior mandibular fractures. Conclusion: All of these modalities were able to achieve satisfactory final outcome. The rigid fixation techniques achieved similar results with less hardware and required lesser times. The MP fixation techniques, on the other hand, are more versatile and less technique sensitive.
Keywords: Anterior mandibular fractures, fixation devices, fracture stability
|How to cite this article:|
Uppada UK, Sinha R, Tiwari P, Vennela S, Khan TA. Evaluation of efficacy of various fixation devices in management of anterior mandibular fractures: A prospective clinical study. J Dent Res Rev 2019;6:69-73
|How to cite this URL:|
Uppada UK, Sinha R, Tiwari P, Vennela S, Khan TA. Evaluation of efficacy of various fixation devices in management of anterior mandibular fractures: A prospective clinical study. J Dent Res Rev [serial online] 2019 [cited 2020 Jun 2];6:69-73. Available from: http://www.jdrr.org/text.asp?2019/6/3/72/273908
| Introduction|| |
Anterior mandibular fractures (AMFs) are fractures that involve a region bounded bilaterally by vertical lines just distal to the canine teeth (the parasymphysis or symphysis). They represent a considerable proportion of mandibular injuries, accounting for 14%–30% of all mandibular fractures.,, This part of the mandible is deceptively complex to repair or reconstruct. The thick and dense cortical bone along with the absence of any vital structures in this anatomical region and ease in accessibility through an intraoral approach makes this appear to be a safe and predictable area for open reduction internal fixation (ORIF). However, biomechanically, this is among the most complex anatomic units due to the eccentric forces resulting from the attachments of muscles of mastication. There have been reports where such fractures have suffered nonunion when managed conservatively.
Literature is replete with articles stating the availability of various fixation devices that can be used in the management of AMFs. However, there is not a single study which compared and evaluated the efficacy of these fixation devices in the management of AMFs. Hence, this study aims to evaluate the applicability, reliability, and stability of various fixation techniques in the management of fractures of the anterior mandible.
| Materials and Methods|| |
The study included forty patients undergoing ORIF for anterior mandible fixation between the periods of January 2014 and June 2018. Patients having recent, noncomminuted, uninfected fractures anterior to the mental foramen were selected and divided into four random groups using an envelope method of randomized sampling to be treated with one of the four fixation techniques. Patients with any associated fractures of the mandible, preexisting hardware in the area, infectious or other lesions, or systemic conditions that interfere with the bone healing process were excluded from the study. The participants were given detailed information about the procedure to be performed, and written informed consent was obtained for treatment as well as participation in the study. The study sample was divided into the following groups:
- Group I – Miniplate (MP) group: Patients underwent ORIF using two parallel 2.0-mm standard MPs with a minimum of four holes
- Group II – Three-dimensional (3D) plate group: 2.0-mm rectangular plates with standard four holes were used
- Group III – Lag screw (LS) group: Two 2.7-mm LSs, with a head diameter of 3.2-mm, 14-mm long were used
- Group IV – Herbert bone screw (HBS) group: Two 2.3-mm HBSs, with a shaft diameter of 1.25 mm, a cortical head diameter of 2.3 mm, and a 2.0-mm cancellous head were used.
A detailed history and thorough clinical examination were performed and recorded for every patient, and the procedures were performed by the same surgical team for all patients. The patients were evaluated clinically and radiographically immediate postoperatively and at periodic intervals of 1 month, 3 months, and 6 months.
The primary outcome variable was the stability of fracture fixation and healing as assessed clinically by interfragmentary mobility bimanually and occlusion with the aid of proper molar relations and overjet and radiographically by the presence of any abnormal alignment or radiolucent line at fracture site as seen on the Orthopantomogram (OPG). The secondary outcome variables included presence or absence of neurosensory deficits using two-point discrimination and pinprick test, development of infections, wound healing assessed clinically, and the mean duration of procedure for each fixation technique.
| Results|| |
The demographic data revealed a male gender predilection in all of the groups (85%, n = 34), with a mean age of 27 ± 1.8 years. All the forty patients included in this study sustained an isolated fracture of the anterior mandible. The most common etiological factor was found to be road traffic accidents (72.5%, n = 29); the remaining injuries were as a result of interpersonal violence (22.5%, n = 9), accidental fall (2.5%, n = 1), and sports-related injuries (2.5%, n = 1). Fifteen patients (37.5%) had a symphyseal fracture, 17 (42.5%) patients had a right parasymphyseal fracture, and the remaining eight patients (20%) had a left parasymphyseal fracture.
The primary outcome variable, interfragmentary mobility across the fracture line was assessed. One case (10%) in the MP group showed slight mobility at the first postoperative week, which required Intermaxillary fixation (IMf) and had resolved by the 6th postoperative week. No mobility was noted in any of the cases in the other two groups, as shown in [Graph 1]. Examination of occlusion showed satisfactory intercuspal and canine occlusal relation in all the participants.
At the end of 1 week postoperatively, two cases in the MP group showed altered sensation in the lower lip which had recovered completely by the end of the follow-up period (6 months). Only one participant in the LS group showed postoperative wound dehiscence at the end of the 1st postoperative week, which was treated by irrigation and wound debridement and recovered without any further complications. No wound dehiscence was encountered in the other three groups, as shown in [Graph 2].
Infection was encountered in two patients (20%) in the MP group during the 1st-month postoperative phase which could be attributed to the poor oral hygiene maintenance of the patients as well as comminuted nature of the fracture in these patients.
The mean duration of procedure for ORIF using different fixation techniques was measured in minutes from the time of placement of incision till the completion of the procedure. Fixation of MPs required the mean longest time (39.4 min) followed by 3D plates (33.2) and Herbert screw (30.2). The shortest procedures were seen for LS placement (25.2) as shown in [Graph 3]. Mean pain scores (Visual Analog Scale) also reflected a similar trend where the highest pain in the 1st postoperative week was reported by the participants in the MP group (3.6), followed by 3D plates (3.3), Herbert screw (2.0), and LS (1.6) as shown in [Graph 4]. The results are tabulated as shown in [Table 1].
| Discussion|| |
Literature is replete with studies emphasizing on numerous fixation devices providing enough functional stability to withstand functional strains and minimize interfragmentary mobility during active use of the mandible. The choice of the fixation device is usually based on the surgeon's preference, experience, anatomical location, and type of fracture. Successful treatment of AMFs depends on undisturbed healing in the correct anatomical position under stable conditions. Failure to achieve this leads to infection, malocclusion, or nonunion. Achieving such stability is a challenge in this region because of the excessive torsional stresses that are present along with the challenges presented in application of hardware due to the overall parabolic shape as well as the surface contour of the anterior mandible. The standard fixation technique used has been MP fixation relying on Champy's principles. This study aimed to evaluate the efficacy, viability, and reliability of 3D plates, LSs, and Herbert screws in comparison to the MPs for fixation of AMFs.
Although many consider the anterior mandibular region to be a safe zone due to the absence of any major neurovascular structures within the bone or directly in the path of incision, this area presents different types of challenges. One such issue is amount of bone height available for hardware application. In many cases, lack of adequate bone height hinders the placement of hardware in accurate positions when adequate safety margin has to be maintained so as to not damage the roots of anterior teeth. Furthermore, the mental nerve, although not directly involved, can be damaged due to stretching or pressure during exposure of the fracture site or placement of MPs. Then, there is the issue of whether the MPs with monocortical screws provide enough stability and strength to withstand the torsional stresses generated in this area. To overcome this lacuna, 3D rectangular plates have been designed. The presence of metal struts connecting the superior and inferior arms gives it a much-enhanced resistance to torsional stress.
The uncertainty of stability of monocortical fixation is why many authors swear by compressive osteosynthesis using LSs in this area, as it provides better initial stability, promotes contact healing, reduces any movements between the fracture segments, and therefore, allows early mobilization with lesser risk of complications. LS achieves compression by its head and requires countersinking to achieve it while avoiding complications. Improper countersinking of LS head is one of the most commonly seen errors while utilizing the LS and can lead to damage to the buccal cortex. Herbert screw is another technique of compressive osteosynthesis which improves upon the disadvantages of LS, namely the chances of stress concentration and damage to the buccal cortex. LS edges over HBS in its ability to achieve good compression and at the same time reducing the steps of its placement and minimize the amount of drilling. Herbert screw, being a headless screw, achieves compression by differential pitch of threads on the buccal and lingual parts avoiding any risk to the integrity of buccal cortex.
In this study, the long-term fracture stability and occlusion were found to be similar and satisfactory with the use of all the techniques. In the immediate postoperative period, one case treated with MP fixation showed minor interfragmentary which was managed with IMF and did not have any long-term complication. This is in alignment with various other studies that have compared LSs or 3D plates with MP fixation and found them to be slightly better with a lower rate of complication. This can be explained with improved mechanical characteristics of the 3D plates while reducing the amount of hardware being implanted in the body.
The major advantage of the 3D MP technique is its geometrically stable configuration using struts connecting the two horizontal arms, allowing simultaneous stabilization of the tension and compression zones obviating the need for two separate plates to be adapted. Because the screws are arranged in the configuration of a box on both sides of the fracture, a broadband platform is created, increasing the resistance to twisting and bending of the long axis of the plate. Although no such complication is noted in our study, the unmodifiable vertical dimension of these plates makes it challenging in cases where the bone height available inferior to the mandibular anterior teeth is less and may result in a damaged tooth root or a plate palpable at the lower border due to its prominence or exposure in the labial sulcus.
Two patients in the MP fixation group showed sensory deficit in the lower lip in the immediate postoperative period, but it was transient. This can be explained by the much wider exposure and retraction required to adapt a four-hole long MP in the anterior mandible. Since all other modalities included significantly less hardware, it stands to reason that the exposure and retraction required for these will be significantly less, thereby reducing the manipulation of mental nerve for fixation of parasymphysis fractures.
We also evaluated the duration of procedure in all techniques. In this study, the LS fixation required the shortest procedure with the Herbert screw requiring slightly longer time. MPs took significantly longer time to apply properly and were the longest procedure compared to other fixation devices with 3D plate being the next. The compressive screw fixation techniques were both significantly faster than the plating techniques as they avoided the need for adapting hardware to the bone contour which in some cases can be very irregular. Here, the Herbert screw needed slightly longer for application as there were more steps in the procedure using multiple drills and taps for fixation. To add to this point, the Herbert screw has a slight limitation in this respect as it needs more specialized equipment.
The operative time when using either of the plating systems was significantly more than the screws, but the 3D plate required slightly lesser operating time than the MPs as the amount of hardware to be adapted as well as the no screws to be fixed are less. This minor reduction in operating time comes with the advantage of better mechanical properties but at the same time has limitations of versatility due to the fixed shape and size.
All these factors contribute to the patient comfort in the immediate postoperative period. The immediate stability and rigidity of fixation, amount of hardware implanted, and the amount of tissue manipulation have a cumulative effect on the amount of surgical trauma and consequently the postoperative pain. Thus, our findings in this study sound reasonable, wherein we found that pain scores were significantly less in both screw systems with a slightly better result in LS due to the significantly less exposure and tissue manipulation required. Within plating systems also, 3D plates showed slightly better scores due to the lesser length requiring shorter area of exposure and lesser hardware compared to the two MPs.
The most popular technique for mandibular fixation has been MPs over the years due to its versatility of application and low technique sensitivity of the procedure. It is available in various sizes, and configurations make it easy to apply in almost any fracture alignment and direction. The major advantages of the lag-screw technique, on the other hand, are that it can be applied more rapidly, provides excellent rigidity, and allows a more anatomically accurate reduction by application of compression across the fracture.,, The major disadvantage here is excessive compression and stress concentration in the buccal cortex endangering its integrity during screw tightening. This is ameliorated to some extent with the Herbert screw due to its headless design and slightly different method of achieving interfragmentary compression.
The blind bicortical placement of the LS and HB screw makes it more susceptible to cause injuries to neurovascular bundle as well as the teeth in the mandible. In the anterior mandible, the absence of any neurovascular bundle makes it much more amenable to fixation with bicortical screws. Injury to the roots of the mandibular anterior teeth is possible in either fixation system but is easier to avoid in MPs due to the use of monocortical screws available in different sizes, especially in the anterior mandibular region where the teeth are visible and easy placement of the plate below the undulations of the alveolar bone that surrounds them. Proper selection of the length of the LS and HB screws as well as assessing the length of the anterior roots with proper preoperative radiographs can eliminate such errors. Another problem encountered with LS and HBS system is the tendency to accidentally over drill the traction hole in the distal bony segment, decreasing the grip of the screw in the far buttress, leading to suboptimal fixation which requires preparation of another traction hole.
One area where the screw systems have a limitation is the angulation of fractures. These systems are ideally suited to oblique fractures as the screw ideally needs to go perpendicular to fracture line. The MPs have the advantage of application in a variety of fracture patterns. That is why over time the use of MPs became the most popular method of ORIF.
| Conclusion|| |
In this study, all the methods of internal fixation have achieved similar and satisfactory results in the long term. However, the alternative fixation methods had some distinct advantages in the immediate postoperative period which cannot be ignored completely. The compressive fixation techniques have some limitations on their indications, but they did provide better initial stability, required lesser exposure, and less soft-tissue manipulation, thus improving pain and patient comfort. This makes these techniques worth a consideration wherever these techniques are viable and available. The final choice of system, however, depends on the specific indication as well as the judgment, experience, and comfort of the practitioner.
Consent was obtained from all the patients.
Financial support and sponsorship
This was a self.funded study.
Conflicts of interest
There are no conflicts of interest.
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