Treatment

Preoperative preparation usually includes verification that the horse has been vaccinated against tetanus, initiation of antimicrobial therapy, administration of a non‐steroidal anti‐inflammatory drug (NSAID), lavage of the oral cavity with a dilute antiseptic solution (e.g., 0.1–0.2% povidone–iodine), and routine surgical preparation of the lip.

The skin and oral mucosa are undermined 1–1.5 cm from the margin of the wound, using a #10 scalpel blade to separate them from underlying musculature (Figure 11.3a,b). Non‐absorbable, monofilament, size 0 or 1 suture material is preplaced in a vertical mattress pattern, with stents, through the isolated musculature centrally so the knots and supports, when later tied, remain on the outside of the lip (Figure 11.3c,d).

The mucosa is apposed with a simple interrupted or continuous suture pattern using size 2‐0 or 3‐0 synthetic absorbable suture material (Figure 11.3e), except at the mucocutaneous junction where one or more vertical mattress sutures are placed to minimize the likelihood of dehiscence. The preplaced sutures are then tied, over soft rubber tubing, and the skin apposed with an interrupted vertical mattress pattern of 2‐0 monofilament, non‐absorbable suture. Using a vertical mattress pattern to close the skin, rather than a simple interrupted pattern, prevents inversion of the skin edges.

A similar approach is used to revise a laceration that has healed by second intention, except that dissection of the skin and mucosa begins at the scarred mucocutaneous junction (Figure 11.4a,b) and is continued until the skin and mucosa have been undermined approximately 1.5–2 cm from the margin of the wound. The preplaced vertical mattress sutures should exit the skin at least 2 cm from the skin edges (Figure 11.4c). The rest of the closure is the same as for an acute laceration (Figure 11.4d).

Tension on a sutured laceration at the commissure of the lips increases tremendously when the mouth is opened (Figure 11.5a,b). To counter this tension, at least two additional vertical mattress sutures, with stents, of size 1 or 2 monofilament non‐absorbable suture material should be placed rostral to the repair, through the uninjured lips (Figure 11.5c,d).

The horse should receive antimicrobial therapy and a NSAID postoperatively for 3–4 days, and can be fed its normal ration. The patient can be cross‐tied, and even sedated or tranquilized, if it attempts to rub the repaired lip. The additional tension sutures with stents, placed rostral to the repair, can be removed in 7–10 days, and skin sutures are removed in 14 days. Dehiscence, if it occurs, usually starts at the mucocutaneous junction. When a lip laceration is sutured using proper surgical technique, healing is by primary intention, and cosmesis and function are good.

Treatment

Although motor function to the lips cannot be restored, a wedge resection of the lower lip aligns the lips sufficiently to restore a buccal seal, which prevents slobbering and drooling and often improves the cosmetic appearance of the lip.^3–5 The amount of lower lip to excise is estimated by comparing the lower lip to the upper lip when the two are pressed together so that they become aligned in a normal position. Because both the upper and lower lips droop when the horse is anesthetized, the preferred technique is to push them both back from their sagged position by applying pressure on the muzzle, thus causing the lower lip to bulge laterally, allowing an estimate of the amount of tissue to be removed.

A full‐thickness, triangular wedge of lip, the apex of which is directed ventrad, is excised to the reflection of the mucosa on to the gum, (Figure 11.9c). The mucosa and skin are sharply separated from the underlying atrophied muscle for 1–1.5 cm from the right and left aspects of the margins of the wound. Sutures are preplaced in the musculature using a vertical mattress pattern, with stents, as described earlier. The mucosa is sutured from within the oral cavity, using 2‐0 synthetic absorbable suture material placed in a simple interrupted or simple continuous pattern, so that the knots are located orally. The skin is apposed with 2‐0, non‐absorbable monofilament suture material placed in a vertical mattress pattern, and the preplaced tension sutures are tied (Figure 11.9d).

Antimicrobial therapy and a NSAID are administered before surgery, and administration is continued for a few days postoperatively. The horse should be observed closely for signs of rubbing at the surgical site; if observed, administering a tranquilizer and continuing the administration of the NSAID usually prevent rubbing. If they do not, the horse should be cross‐tied for a week to prevent rubbing of the surgical site. Dehiscence, if it occurs, usually begins at the mucocutaneous junction. Tension sutures can usually be removed at 7–10 days, and skin and mucosal sutures at 14 days. A cosmetic and functional outcome is usually achieved (Figures 11.9e,f).

Treatment

Preoperative preparation includes administration of an antimicrobial drug and a NSAID. The oral cavity is lavaged to remove feed, and the tongue and wound are gently scrubbed with a mild antiseptic solution using a gauze swab.

Small lacerations at the tip of the tongue can sometimes be repaired with the horse standing, but the horse should be anesthetized if the injury is extensive or located more caudally than at the tip. The tongue of the anesthetized horse is exteriorized by exerting traction on a towel clamp placed through the tongue, or on a gauze loop, placed around the tongue, caudal to the laceration. The exposed wound can be isolated by draping (Figure 11.11a).

The margin of the wound is excised with a scalpel. Excising anything more than a narrow margin causes the sutured tongue to deviate dorsally or laterally. Accurate closure of dead space and approximation of tissue edges are imperative to prevent dehiscence, because constant movement of the tongue and the presence of saliva, bacteria, and feed hinder healing. The lacerated sides of the tongue must be apposed accurately.

The mucosa of the dorsal surface of the tongue is thick and dense and has great strength and, therefore, holds tension sutures well. The tongue should be sutured using absorbable suture material to eliminate the necessity for removing sutures. A vertical mattress tension pattern using 0 or 1 monofilament, absorbable suture should penetrate the laceration into the musculature centrally so the knots, when later tied, reside on the dorsal aspect of the tongue (Figure 11.11b). This layer provides great strength to the repair. Before tying the vertical mattress sutures, synthetic absorbable monofilament sutures (0 or 2‐0), are used to appose the lacerated muscles and eliminate dead space. The mucosa of the tongue is also apposed with a vertical mattress suture pattern (Figures 11.11c,d) or a combination of vertical mattress and simple interrupted suture patterns.

If the tongue must be amputated, a transverse wedge‐shaped piece of tissue is removed from the remaining stump, creating dorsal and ventral flaps that are closed with a horizontal or vertical mattress suture pattern.^3–5 Horses can be expected to eat and handle a bit normally after amputation of the tongue to the level of the frenulum.¹⁷

Administration of antimicrobial therapy and a NSAID is continued postoperatively for 3–5 days. Feeding a soft food may ease the comfort of the horse. A good functional result can be expected in most cases (Figure 11.11e), even if a portion of the tongue requires amputation.

Treatment

Acute lacerations of the dorsal arch of the nostril (Figure 11.13a) should be sutured with 2‐0 monofilament nylon in an interrupted, modified figure‐of‐eight pattern to appose the skin on the outside of the nostril and skin within the false nostril (Figure 11.13b‐d).^3–5 The advantages of this approach to suturing are speed of application, good apposition of all tissue layers, and the ability to remove the sutures by cutting a single loop. Alternatively, simple interrupted sutures can be used, but gaping of the wound between the sutures is common.

Acute lacerations of the base of the nostril are usually best handled by primary closure (Figure 11.14a).^3–5 After the site is prepared for surgery, the nostril is packed with sterile gauze, and drapes applied to the area (Figure 11.14b). The wound should be debrided, but care must be taken to not further compromise the blood supply to the flap (Figure 11.14c). Because this area is subjected to high motion from movement of the upper lip and alar cartilage, a three‐layer suture closure is recommended (Figure 11.14d) to provide security and good approximation of tissue. The skin inside the false nostril is sutured from within using a continuous‐horizontal mattress suture pattern of 2‐0 synthetic absorbable suture material (Figure 11.14d). The deep tissue is apposed in a simple interrupted fashion, and the skin is sutured with 2‐0 monofilament non‐absorbable suture using an interrupted vertical mattress pattern (Figure 11.14d,e).

A chronic laceration of the base of the nostril presents a special problem because the flap of tissue may be smaller than its original size due to contraction (Figure 11.15a,b).^3–5 The flap must be incised to create fresh edges that are then undermined to reform the inner and outer epithelial layers at the base of the nostril. When creating these fresh edges, only a minimal amount of tissue should be excised (Figure 11.15c).

The first step is to make an incision in the base of the nostril that extends rostrally along the line of injury from the base of the flap to the site where the most rostral tip of the flap should reside, without reducing the luminal diameter of the nostril. The skin on the dorsum and on the ventrum of the base of the wound is undermined to produce two edges of tissue for internal and external closure (Figure 11.15c). Inner and outer edges are created in the tissue flap in a similar manner (Figure 11.15c). The fresh edges produced by these incisions are sutured as described previously for acute lacerations. The freshened edges are apposed by suturing from the base of the flap toward the tip of the flap (Figure 11.15d,e). Alternatively, closure can be started by suturing the tip of the flap to the appropriate site on the base of the nostril. Pulling the flap too rostrad may result in stenosis of the nostril and increases tension on the sutured wound.

Postoperative care is similar to that for repair of other lacerations of the nostril. A muzzle that covers the nostril, while allowing the horse to eat and drink, can be applied to prevent the horse from rubbing the surgical site (Figure 11.15f). Lacerations of the nostril generally heal well, and a good functional and cosmetic result can be obtained if the principles in this section are followed; otherwise, results can be very disappointing.