Management of unilateral oblique mandibular fracture with interfragmentary wiring technique in a Shih Tzu dog - A case report

Introduction

A fracture in the jaw can range from a greenstick (incomplete crack) to severe comminution. Mandibular fracture may result from trauma, neoplasia, concurrent injuries like upper airway obstruction, pneumothorax and severe periodontitis. One of the major causes include trauma due to vehicles as dogs tend to freely wander and injuries during fights between dogs. Thoracic injuries occur concomitantly further observed as pulmonary contusion, pneumothorax, diaphragmatic hernia and traumatic myocarditis. Pathological fractures tend to affect older animals than young animals. The tooth roots, nerves, blood vessels and salivary duct are located within and adjacent to mandible with a high risk of being damaged during the fracture (Fossum). Surgical intervention of fracture is considered if the site of injury is unilateral or bilateral. The techniques that can be employed for the same include tape muzzles, circumferential wiring, interdental wiring, acrylic splints, percutaneous skeletal fixation, intramedullary pinning, bone plating and partial mandibulectomy (Kachwaha et al., 2011) [7] . Application of tape muzzle is an inexpensive option which favors rapid healing of minimally displaced fractures but difficult for repair of fracture in the vertical ramus (Harasen et al., 2008) [4] . Circumferential wiring is effective for fractures in the mandibular symphysis where orthopedic wire is secured around the front parts of both jaws, with the help of large-bore needles (Higgins et al., 2013) [3] . External fixation is an effective method wherein minimum of two pins or screws are placed percutaneously in each fragment, avoiding the mandibular canal. Its disadvantages are its increased expense and its use being limited to larger dogs (JR Davidson et al., 2022) [6] . The ultimate aim of the surgery performed is to mimic the anatomical alignment of the fractured portion of the jaw hence facilitating mastication and prehension to the maximum. Healing of the site further depends on the level of vascularity retained and the absence of infection at the site of fracture. Advantages of interfragmentary wiring include precise alignment with minimal deformity, minimum tissue invasion further promoting rapid healing and minimal cost (Uma Rani et al., 2022) [10] . Further this case reports highlight the successful treatment of unilateral oblique mandibular fracture in a Shih Tzu dog by employing interfragmentary wiring technique. ) Animal was placed in left lateral recumbency and the surgical site was shaved and aseptically prepared. Under general anesthesia, a 1.5mm K -wire was used for the correction of the mandibular fracture by a driller and the sharp tip was sealed with epoxy (Figure 3) Radiographic examination of the mandibular region revealed the presence of the implant intact at the site (Figure 4). The animal was advised to maintain on fluid therapy for the next 2 weeks alongside administration of antibiotics, analgesics with minimal jaw movement.

Results and Discussion

On 24 th day in the post operative radiographic examination the pin was found to be intact and callus formation was noticed. On the 45 th day the radiographic examination elucidated a proper alignment and fracture healing at the site of injury favoring the removal of the implant. Animal showed uneventful recovery (Figure . 5).

As mentioned earlier there are several methods for the correction of mandibular surgery which majorly focus on retaining normal occlusion that provide rigid fixation and therefore an early return to function. Due to the unique forces that mandibular fractures endure compared to other bones, veterinarians face numerous challenges during the surgical correction of these fractures (Harasen et al., 2008) [4] . In this case, interfragmentary wiring was chosen due to the fracture's location, the time elapsed before referral, the severity of the fracture and the fact that the animal is a brachycephalic breed. We have utilised a K-wire with a diameter of at least 1.0-1.5 mm fixed to an electric driller and the wire was inserted percutaneously across the fracture site from the horizontal ramus till the level of ventral ramus and the external portion secured with epoxy. The possible complications are loosening of the wire, malalignment, development of submandibular abscess, intraoral ulceration, osteomyelitis and ventral deviation at the site (Imani Rastabi et al., 2017) [5] . However, no such complication was observed in this case.

Conclusion

Interfragmentary wiring technique using 1.5mm K-Wire was used for the correction of oblique fractures in the horizontal ramus of the right mandible of a Shih Tzu dog. This procedure is economical, effective and less invasive, causing minimal disturbance to the animal therefore this technique is highly preferred.

References

1. Higgins BM. Fractures of the mandible; 2013.
2. Rastabi HI, Moarabi A, Khajeh A, Kavosi N. Management of bilateral mandibular fracture in a single-humped camel; 2017.
3. Davidson JR, Bauer MS. Fracture of mandible and maxilla; 2022.
4. Kachwaha K, Parashar MC, Gahlot TK. Accidental mandibular fracture in a pup and its surgical management; 2011.
5. Varghese R. Surgical management of mandibular fracture and tongue laceration following firecracker explosion in the mouth of a four-year-old dog; 2019.
6. Rani UR, Sowbarenya C, Arun R, Arulnandam K, Vishnurahav RB. Interdental wiring and epoxy-pin external fixation for mandibular fracture management in dogs; 2022.