Head wounds

Horses often suffer wounds to the head and face due to many situations. Loading and trailering often contribute to these types of injuries as horses can rear when entering a trailer and cause a flap-like scalping injury to the top of the head. Because of the close quarters in trailers, horses can bump and injure their heads during travel, too. Protective headgear is recommended to prevent these problems.

Horses often suffer head injuries that include sinus bone fractures and fractures of the zygomatic arch above the eye because of direct trauma from kicks, mallet strikes (in polo ponies), from falls while on a cross-country course or in a jumping arena, as well as from becoming cast and struggling in a stall. Lacerations to the nostrils, eyelids, and corners of the mouth, lips and tongue are all commonly seen. These injuries are most often due to interaction with environmental objects such as wire, other fence material, nails, bucket hooks and similar protruding obstructions or from bite trauma.

Inaccurate closure of the eyelids can result in excessive tear loss from the eye and marking of the side of the face as well as possible corneal irritation and visual difficulties.

Head wounds are relatively easy for owners and barn managers to notice, so they usually are brought to a veterinarian's attention quickly. Exceptionally good blood supply and pliable tissue that is not generally under much tension, except for the midline of the forehead, generally allows for effective surgical repair. Because of the potential for underlying bone damage, all injuries to the head and face should be carefully evaluated, and radiographs should be taken if needed. Thorough debridement and flushing of head wounds sometimes will identify small bone fragments or bits of foreign material that must be cleared from the wound before closure is attempted.

Wounds that penetrate into a sinus usually can be closed because serum and blood forming below the wound will drain to the sinus and be resolved there. These horses often will show significant nasal discharge for a few days following trauma, and owners should be advised of this complication. Antibiotic therapy and occasionally even flushing of the sinuses will reduce the potential for post surgical complications in these types of injuries.

Lacerations to the eyelids, lips, tongue, mouth and nostrils require precise anatomical closure for both functional and cosmetic reasons. Inaccurate closure of the eyelids can result in excessive tear loss from the eye and marking of the side of the face as well as possible corneal irritation and visual difficulties. Problems with correct closure of injuries to the nostrils are more likely to result in a poor repair that can be cosmetically unacceptable to the owner and can reduce the value of that horse in the future. In extreme cases, poor nostril closure may affect airflow in conditions of maximal exercise. Problems with closure of injuries to the mouth, tongue and lips can result in eating difficulties or problems with the bit but usually fall into the category of poor cosmetics. Often these failed first surgical attempts can be repaired at a later date, but good accurate closure of a primary injury is still the best approach when possible.

In order to achieve this good anatomical closure, the wounds should be cleaned and evaluated to ensure that the surgeon is attempting to reposition tissue correctly and that healthy tissue is being used for the repair. Injuries to the nostrils, mouth and lips often include thin strips of tissue or pieces of skin that have undergone blunt trauma. This can damage blood supply to this tissue resulting in devitalized material that will die and subsequently slough. Utilization of this damaged tissue in wound repair will doom that repair to failure.

Occasionally, a surgeon will use such damaged tissue knowingly because there are no other alternatives for closure, and even partial repair for a short time will allow for the beginning of a granulation response in tissue below the injury. This is a situation where a second reconstructive surgery will be planned from the start, and this probable progression should be communicated to the owner.

Correct closure of individual tissue layers in wounds to the eyes, mouth, tongue, lips and nostrils will result in a better, stronger repair with less chance of surgical failure. While the vast majority of these injuries can be done in the standing horse with a combination of general tranquilization and local anesthetic blocks, some injuries may benefit from general anesthesia if this allows for more correct and complete closure. Insufficient attention to closure of the inner layer of these types of wounds is perhaps the most common reason for problems. Closure of the surface or skin layers initially will result in a nice-looking surgery, but the deeper layers and especially the inner layers of repairs to the mouth, eyes and nostrils will determine healing and post-repair tissue strength. Anatomic closure of these inner layers, often requiring the burying of sutures, is crucial to the success of these types of repairs.

Dr. Scott Taylor, a surgeon at the Arizona Equine Medical and Surgical Center, had seen many such repair attempts fail and has developed his own approach to these injuries.

"Though some may feel that this approach is overkill, it has worked well for me," Taylor says. He advocates repair under general anesthesia and separates the wound into three separate layers (mucosa, muscle and skin) for individual closure. Use large (1-2 nylon) tension sutures in the skin, placed in a vertical mattress pattern with large button stents placed 2 cm apart and 2-3 cm from the skin edge."

He then suggests Prolene or nylon interrupted sutures between the tension sutures to achieve good tissue apposition.

"In some cases, one can use medical-grade super glue or tissue adhesive along the mucosal and skin edges to prevent saliva from entering and disrupting the repair," he says.

Injuries to the eyes, mouth and nostrils often are not well tolerated by horses. As the skin begins to heal, these animals generally become itchy and will rub and abrade their sutures and/or staples. The use of a protective eye-cup halter or grazing muzzle sometimes can allow these injuries time to heal. Removing the protection too early is a common cause of repair failure.

"I recommend that these head wounds generally be protected from self trauma for a period of two weeks," Taylor says.

Not all face injuries need such an intense approach, but the principles of thorough debridement, accurate anatomical reconstruction and post-operative protection apply to head wounds of all types.

Editor's Note: In the first of a three-part series, Dr. Kenneth Marcella discusses wound care with leading practitioners. Subsequent stories will include body wounds, leg lacerations, heel and coronary band lacerations, puncture wounds involving tendons or ligaments, and rope burns and wire cuts to the caudal pastern and foot. Look for DVM Newsmagazine's Wound Care Quiz to follow the final installment of this series.

Dr. Marcella, a 1983 graduate of Cornell University's veterinary college, was a professor of comparative medicine at the University of Virginia. His interests include muscle problems in sport horses, rehabilitation and other performance issues.