Equine head wounds and skull fractures

Photo: New Africa/Adobe Stock

Figure 1a. Traumatic open wound on an adult horse showing a laceration over the left side of the face and bony fragments protruding from the laceration.

Figure 1b. Corresponding CT image identifying an open, complete, and displaced fracture of the skull involving the left paranasal sinuses.

The presentation of horses for wound evaluation following trauma is a frequent occurrence and one of the most common emergency presentations in equine medicine.¹ Horses can sustain wounds over any part of their body, with the distal extremities and head region being common locations for injuries. Like in the distal extremities, there is little soft tissue coverage in the head region, and in up to 80% of cases head lacerations can be accompanied by a traumatic fracture of some part of the skull, making them slightly more challenging to manage.²

In one study, fractures involving a horse’s head following a kick from another horse comprised 12% of all incidents and were the second most common type of fractures, following splint bone fractures.³ A thorough knowledge of the horse’s anatomy is needed when addressing trauma and lacerations in the head region. Vital structures found in a horse’s head include the eyes, cerebrum, paranasal sinuses, and nasolacrimal duct.

Skull fractures

The equine skull is complex and composed of bones including the incisive bone, nasal bone, frontal bone, maxilla, lacrimal bone, zygomatic bone, interparietal bone, parietal bone, temporal bone, sphenoid bone, occipital bone, ethmoid bone, palatine bone, vomer, pterygoid bone, and mandible.⁴ The most common bones injured in skull fractures are the nasal, frontal, and maxillary bones with the zygomatic process of the frontal bone.⁵ Additionally, lacerations to the face and subsequent facial bone fractures can be complex and involve various structures such as sinus compartments, the lacrimal duct, orbit, and cerebrum (Figure 1a and Figure 1b).

Figure 2a. A traumatic laceration of the right side of the face in a foal which could only be closed partially by primary closure.

Figure 2b. Corresponding CT image on the right identifying an open, comminuted displaced fracture of the skull involving the 507 tooth.

Figure 3a. Same filly as on Figure 2a, 2 years post injury. Owners were very satisfied with the outcome and cosmetic appearance of the filly. No complications were noted post treatment.

Figure 3b. Corresponding recheck CT of the filly showing good healing of the fracture, which was treated conservatively despite the initially severe displacement.

As they are frequently traumatic in origin, these fractures are often open, displaced, and comminuted with numerous fragments of various sizes. Clinical signs will vary according to the extent of the trauma and can often include multiple lacerations ranging from small abrasions to large, full thickness wounds, nasal epistaxis, emphysema, stertorous breathing, and crepitus. Associated skull fractures should be examined thoroughly to obtain a comprehensive and complete evaluation of the extent of the damages. In addition to a general physical examination, a comprehensive examination including ocular, oral, and neurological evaluations (cranial nerves) should be undertaken.⁴ Further diagnostics such as an upper airway endoscopy, radiographs, ultrasound, and CT images will often help characterize the full extent of the trauma.^6-8

The ample blood supply to and low physical load on this type of injury allow for a good prognosis following treatment even when associated with a skull fracture. Wounds will be treated routinely using a combination of clipping, cleaning, and copious flushing. These wounds are usually moderately to severely contaminated and, therefore, should be debrided accordingly.⁹ When the wound is associated with a skull fracture, several treatment options can be considered, the majority looking at stabilization of the fracture site. Surgical treatment has been reported to be the best choice for open fractures, while conservative management has reportedly been associated with greater risks of wound infection, delayed wound healing, and sequestrum formation.³ It has also been postulated over the years that inadequate reduction would result in inferior cosmetic outcome, especially if a prominent callus formation is present, but there is little published scientific reference to that regard.^10-14 Various surgical repairs for skull fractures have been described over the years. In some cases, the fractured bone segments may be able to be elevated by sliding an instrument through small holes drilled away from the fracture. Once elevated, some of the fragments may not need further intervention but in some cases internal fixation using cerclage wires and implants such as plate and screws may be necessary to stabilize the fracture. There is also an isolated report describing the use of polydioxanone sutures,¹⁰ intrasinus bolstering using Foley catheter balloons,¹² and the use of titanium rosettes1 to repair such fractures.

Wound Cases

Last year, investigators, including this author, analyzed 13 cases that were presented in our practice over the past 4 years.¹⁵ Cases were included if they underwent CT diagnostics of the head with a history of facial trauma and had a fracture of at least 1 of the facial bones comprising the skull. We only included cases that were treated without internal fixation of the skull fracture.

Diagnostic imaging identified the fractures to be complete and comminuted in all cases. The skull fractures were unilateral in 10 horses and bilateral in 3 cases. The most common facial bones involved were the maxilla in 9 horses, the nasal bone in 7 horses, and the frontal bone in 4 horses. The nasolacrimal duct was involved in 3 horses and the infraorbital canal in 1 horse. Secondary sinusitis was present in 10 horses with the rostral maxillary, caudal maxillary sinus, and ventral conchal sinus being the most affected. There was an associated fracture of dental structures in 3 horses (Figure 2a and Figure 2b).

Treatment was strictly conservative in half of the cases, consisting of wound treatment and systemic antibiotics and anti-inflammatories, as needed. In the other half of the cases, some minimal surgical intervention was undertaken and included removal of loose bony fragments and sinus trephine and sinoscopy, fragment removal and sinus flush through a Foley catheter and dental extraction. In most cases, the lacerations were cleaned, debrided, and closed primarily using either simple interrupted or tension-relieving sutures (vertical mattress). In certain cases, given the nature of the laceration, only partial closure was possible leaving a defect to heal by second intention. (Figure 2a)

Follow-up information identified a few cosmetic sequelae, and conservative management yielded a good-to-excellent outcome according to owners in most cases (Figure 3a and Figure 3b). Therefore, conservative management should be considered in cases of skull laceration with associated skull fractures as they still carry a good prognosis with limited complications.

References

1. Furst AE, Auer JA. Fractures of the head. In: Nixon AJ, ed. Equine Fracture Repair, 2nd edition. Wiley-Blackwell. 2019;770-799.
2. Little CB, Hilbert BJ, McGill CA. A retrospective study of head fractures in 21 horses. Aust Vet J. 1985;62(3):89-91. doi:10.1111/j.1751-0813.1985.tb14146.x
3. Nixon AJ, ed. Equine Fracture Repair, 2nd Edition. Wiley Blackwell; 2019.
4. Ragle CA. Head trauma. Vet Clin North Am Equine Pract. 1993;9(1):171-183. doi:10.1016/s0749-0739(17)30422-4
5. Auer JA, Stick JA. Equine Surgery, 5th edition. Elsevier; 2018.
6. Crijns CP, Weller R, Vlaminck L, et al. Comparison between radiography and computed tomography for diagnosis of equine skull fractures. Equine Vet Educ. 2019;31(10):543-550. doi:10.1111/eve.12863
7. Tietje S, Becker M, Böckenhoff G. Computed tomographic evaluation of head diseases in the horse: 15 cases. Equine Vet J. 1996;28(2):98-105. doi:10.1111/j.2042-3306.1996.tb01599.x
8. Solano M, Brawer RS. CT of the equine head: technical considerations, anatomical guide, and selected diseases. Clin Tech Equine Pract. 2004;3(4):374-388. doi:10.1053/j.ctep.2005.02.016
9. Modransky P, Welker B, Pickett JP. Management of facial Injuries. Vet Clin North Am Equine Pract. 1989;5(3):665-682. doi:10.1016/ s0749-0739(17)30581-3
10. Schaaf KL, Kannegieter NJ, Lovell DK. Management of equine skull fractures using fixation with polydioxanone sutures. Aust Vet J. 2008;86(12):481-485. doi:10.1111/j.1751-0813.2008.00369.x
11. Dowling BA, Dart AJ, Trope G. Surgical repair of skull fractures in four horses using cuttable bone plates. Aust Vet J. 2001;79(5):324-327. doi:10.1111/j.1751-0813.2001.tb12004.x
12. Gardner AK, Santschi EM, Mudge MC, Belknap JK, Metzler AG. Intrasinus bolstering of traumatic maxillary sinus fractures by using Foley catheter balloons in two foals. Vet Surg. 2020;49(6):1255-1261. doi:10.1111/vsu.13433
13. Turner AS. Surgical management of depression fractures of the equine skull. Vet Surg. 1979;8(2):29-33. doi:10.1111/j.1532950X.1979.tb00601.x
14. Schumacher J, Brink P. Treatment of horses for a facial or oral fistula. Equine Vet Educ. 2011;23(5):242-248. doi:10.1111/j.2042-3292.2010.00183.x
15. Perrier M, Looijen M, Manso-Diaz G. Equine skull fractures: a review of 13 cases (2018-2022). Presented at: European College of Veterinary Surgeons; July 6-8, 2023; Krakow, Poland.