Surgico-therapeutic management of mandibular fractures in dog

Introduction

Dog has been a cohort animal for humans since centuries and this relationship between humans and dogs keeps on growing stronger and stronger along with increased people's interest towards the care of animals. Dogs have been used not only as guard but also to help in daily routines and especially as companion animals (Iqbal, 2021) [7] . Mandible in dog forms skeleton of lower jaw and comprises of a body and two rami. The two halves of this bone fuses incompletely at the mandibular symphysis, situated at the midline within the body. The mandible is prone to trauma due to automobile accidents, fall from height or dog fights, especially in young dogs. Mandibular fractures may occur spontaneously, due to bone loss secondary to severe periodontal or endodontic infections. Treatment for mandibular fracture repair can be characterized as invasive, involving external or internal fixation devices (such as plates, external fixators, pins, and interfragmentary wires). By contrast, non-invasive treatments rely on closed reduction and tooth-borne devices (such as acrylic composite, interdental wiring, maxillomandibular rigid fixation). Non-invasive interdental splinting techniques preserve periosteal attachment and vascularization at the fracture site and minimize further dental and periodontal trauma compared to invasive treatments (Guzu et al., 2016) [6] . Many techniques are available for managing maxilla-mandibular fractures including plates and screws, specialized mini plates, interdental wires, intraoral splints, acrylic splints, external fixators, intramedullary pins, inter-fragmental or intra-osseous wires, inter-arcade wiring, epoxy resin and polymethyl methacrylate (PMMA), external fixation, dental composite application, tape muzzles and combinations of these methods. Each of these techniques has its advantages and disadvantages and complications are more likely if stable and rigid immobilization is not achieved (Umphlet and Johnson, 1990) [12] . When selecting a repair technique, it is important to consider that placing fixation on the tension side of the bone will maximize the strength of the implant. For the mandible, the tension surface is the alveolar side of the bone. However, placing implants here can risk damaging tooth roots and neurovascular structures so implants are often positioned on a compressive surface which can create a mechanical disadvantage.

The most common repair methods involve various wiring techniques. Surgical wire can be applied in a hemicerclage fashion between fracture fragments or cerclage techniques can be employed especially in mandibular symphysis fractures. Additionally, the wire can be wrapped around teeth adjacent to the fracture to provide stability. Interdental wiring is a straightforward and effective procedure (Umphlet and Johnson, 1990) [12] . Dental bonding or intraoral splints have become popular among veterinary dentists as a non-invasive method for stabilizing certain fractures. Intraoral splints typically rely on the presence of intact teeth on either side of the fracture site and are most effective for mandibular fractures particularly those located rostral to the molars (Niemiec, 2003) [11] . Considering advantages and disadvantages having with the various techniques of mandibular fracture repair, the present study compares the efficacy of orthopedic wiring with and without acrylic application in the surgical treatment of mandibular fractures.

Materials and Methods

A total of 37 cases with oral affections were screened at Veterinary Clinical Complex, Post Graduate Institute of Veterinary and Animal Sciences, Akola during the study period. Out of which 16 dogs with mandibular fractures were included in this study irrespective of age, breed, sex and body weight. These clinical cases were divided into two equal groups comprising eight dogs each which were subjected to two different surgical approaches as mentioned in the table I.

Table 1: Grouping of dogs subjected to two different surgical approaches

Groups Mandibular fracture (N= 16) Surgical Approach

Group I (N=8) Orthopaedic wiring

Group II (N=8) Orthopaedic wiring with acrylic application

The physiological parameters viz, rectal temperature (°F), heart rate (beats/min.) and respiratory rate (breaths/min.) were recorded on the day '0' pre-operative as well as postoperative and 7 th , 14 th , 30 th and 60 th post-operative day. Six anatomical regions were used to classify the mandibular fracture location. These regions were as follows: Symphyseal, Canine region, Premolar region, Molar region, ramus region and condylar region (Umphlet and Johnson, 1990) [12] . Mandible fractures were fixed surgically either by orthopaedic wiring or by wiring along with acrylic (Protemp TM 4) application as a composite material for the fabrication of temporary restorations. All dogs were premedicated with Inj. Atropine sulphate @ 0.02mg/kg subcutaneously, then sedated with the combination of Inj. Xylazine @ 1 mg/kg + Inj. Butorphanol @ 0.2 mg/kg intramuscularly. Anaesthetic induction was performed using a combination of Inj. Midazolam @ 0.2 mg/kg and Inj. Propofol @ 4mg/kg intravenously. Anaesthesia was maintained with isoflurane @ 2% in combination with 100% oxygen. Orthopaedic wiring in Group I was carried out by drilling holes approximately 5mm rostral and caudal to the fracture site, between the roots of the multirooted tooth and then passing the orthopaedic wire through the hole. A handheld drill with 1.7 mm / 2.5mm size bit was used to drill the holes. Orthopaedic wiring was done as a staple suture or 8shaped patterns for different sites of the fracture. In Group II, along with orthopaedic wiring, acrylic was applied as an adjunct for sufficient anchorage. Teeth and metallic surfaces like orthopaedic wire were used as anchorage for acrylic. The material was applied directly over the teeth, on either side of the fracture site from the cartridge loaded in the dispenser. Acrylic was further moulded with gloved fingers to take the shape of the denture and to ensure that there were no sharp edges to cause any injury to the oral mucosa or tongue. Immediately after surgery, skull radiographs (Lateral and Dorso-ventral view) were taken to assess the anatomical reduction of fracture fragments.

The haematological parameters such as Haemoglobin (g/dL), Total Leucocyte Count (N × 10 3 /cu.mm) Differential Leucocyte Count (%) were analysed on day '0' pre-operative and on 7 th , 14 th , 30 th and 60 th post-operative day. Biochemical examination such as Blood Urea Nitrogen (mg/dl), Serum creatinine (mg/dl), Alkaline phosphatase (IU/L), Aspartate aminotransferase (IU/L), Alanine aminotransferase (IU/L), Calcium (mg/dl), Phosphorus (mg/dl) and Total Protein (g/dl) were evaluated on day 0 th, 7 th , 14 th , 30 th and 60 th post-operative day. Radiographic assessments were conducted preoperatively and immediately after surgery to evaluate fracture reduction and at subsequent intervals (14 th day, 30 th day and 60 th day) to monitor the progress of fracture healing (Figure 12345).

Results and Discussion

The incidence of mandibular fractures in dogs were highest due to dog fight (56.25%), followed by automobile accidents (25%), fall from height (12.50%), and the lowest incidence was occured due to direct hit (6.25%). These findings are in accordance with Lopes et al. (2005) [10] who noted that the most common cause of fracture was dog fight (43.0%) followed by automobile trauma (12.0%). The highest incidence of mandibular fractures in the premolar (33.33%) and symphyseal (23.81%), followed by canine region (23.81%), molar region (19.05%), in ramus and condylar regions no fractures observed. The findings are corroborated with the findings of Glyde and Lidbetter (2003) [5] who recorded maximum number of fractures in the mandibular body, most frequently in the premolar region. They opined that it might be due premolar/molar part of the mandible that exposed to traumatic insults, especially those occurring from the side or the bottom direction and it may also be contributed to the presence of a weak site of the immature mandibular symphysis which acts as a predisposing factor for fracture. The incidence of mandibular fractures in dogs was highest in those under one year old (87.50%), followed by the dogs aged 1-2 years with no cases reported in dogs over two years. These findings are aligned with the study of Umphlet and Johnson (1990) and Kitshoff et al. (2013) [12,9] who reported a significantly higher occurrence of mandibular fractures in dogs under one year old. Moreover, they opined that bone mineral content and bone mineral density in younger dogs were found to be lower than older dogs which tend to have maximum mandibular fracture incidences in younger than in older dogs. The highest incidence of mandibular fractures in dogs was observed in Mongrel dogs (81.25%) followed by Golden Retriever, Labrador, and German shepherd (6.25%) each. It is attributed to the high population density of mongrel dogs in and around the Akola city where the study was undertaken. The incidence of mandibular fracture in dogs was found to be higher in males (68.75%) compared to females (31.25%). These findings unison with the studies of Umphlet and Johnson (1990) and Kitshoff et al. (2013) [12,9] who also reported a higher incidence of mandibular fractures in male dogs than in females. This may be attributed to the relatively

aggressive nature and roaming behaviour of male dogs, making them more susceptible to fractures. In the present study, clinical signs exhibited by dogs varied from anorexia, crepitation, jaw mobility upon manipulation, excessive drooling of saliva, oral bleeding, jaw dropping, jaw asymmetry, tongue protrusion and reluctance to eat. Haematological parameters such as Haemoglobin (g/dL), Total Leucocyte Count (x 10 3 /cu.mm) and Differential Leucocyte Count (%) were estimated for both the groups at different intervals. The variations in the values were nonsignificant but remained within normal physiological limits. Biochemical parameters such as Blood Urea Nitrogen, Creatinine, Aspartate amino transferases, Alanine amino transferases, and total protein showed non-significant changes, with values fluctuating within normal physiological limits. However, Calcium and Alkaline phosphatase levels were initially low, peaked on the 14th and 30th postoperative days, and then declined by the 60th day. Phosphorus values significantly elevated and peaked on 7 th postoperative day then followed a declining trend at subsequent intervals (illustrated in table II). These findings are in agreement with the results reported by Boorman et al. (2020), Ghadban and Khashjoori (2022), and Amal (2023) [3,4,1] who also observed that calcium levels were initially normal, followed by a significant increase between the 14 th and 30 th postoperative days, and then returned to normal by the 60 th day. They preached that this increase might be due to the deposition of excess calcium at the fracture site during the healing process.

The rise in calcium levels on the 14 th and 30 th postoperative days was attributed to the fracture healing entering the remodelling phase. Radiographic union score (described by Al-Sobayil et al., 2020) [2] was assessed on '0', 14 th , 30 th and 60 th postoperative day, for all the dogs on the basis of fracture line visibility, presence or absence of callus, fracture healing. In group I, the radiographic union score was 10 in six cases, indicating complete fracture healing by the 60 th postoperative day except two cases. In group II, the radiographic union score was 10 in seven cases, indicating that the fractures had completely healed by the 60 th postoperative day except one case. The functional outcome in all the dogs were recorded based on clinical and radiographic healing assessment. In Group I, three dogs exhibited excellent, three had well and two had poor results. However, in Group II, four dogs showed excellent, three had well, and one had poor outcomes.

Conclusions

Dog fights are the leading cause of mandibular fractures, followed by automobile accidents. Orthopaedic wiring alone proved to be an effective method for managing mandibular fractures in dogs but associated with few complications. Orthopaedic wiring combined with acrylic application provides enhanced structural support, promotes faster healing with minimal complications, and has been proven to be an effective and superior treatment option for mandibular fractures in dog.

Conflict of interest

Not available

Financial support

References

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