Surgical repair of a chronic,oronasal fistula in a horse using an alveolar bone flap

An 8‐year‐old Andalusian stallion was presented to the Equine Hospital with a 1.5 year history of an oronasal fistula measuring approximately 2 cm long (caudal to rostral) by 1.5 cm wide following an oral extraction of the right second maxillary premolar (106). An alveolar bone flap was created adjacent to the oronasal fistula and rotated axially and ventrally to close the oral aspect of the fistula. At 3 days after surgery, clinical signs of the fistula, such as green‐tinged purulent nasal discharge and malodorous breath, were no longer evident. At 10 days after surgery, the oral opening of the fistula filled with granulation tissue and mucosa and decreased in size to less than 2 ml. The horse was fed a pelleted mash and grass diet and the small fistula was flushed orally twice daily until it completely healed. At 6 months following surgery, the fistula had completely healed. Few options are available for repairing an oroantral or an oronasal fistula in horses. This case report suggests that a large, chronic oronasal fistula involving the alveolus of a maxillary second premolar can be repaired successfully with an alveolar bone flap.     

In-hospital development of an aorto-cardiac fistula in a Warmblood gelding with chronic renal disease

A 20-year-old Warmblood gelding presented for evaluation and treatment of ventral oedema and azotaemia of unknown aetiology. On presentation, a diastolic heart murmur was appreciated and echocardiography revealed moderate aortic insufficiency due to chronic degenerative valve disease. The horse was hospitalised and failed to respond to oral and i.v. fluids and diuretics. Following discontinuation of all fluid and diuretic therapy, the horse became acutely agitated and developed monomorphic ventricular tachycardia. The ventricular tachycardia spontaneously converted to normal sinus rhythm, however the heart murmur changed in timing to a right basilar continuous murmur and bounding jugular pulses were noted. Repeat echocardiogram revealed an aorto-cardiac fistula with dissection into the basilar interventricular septum and left-sided chamber volume overload that was not previously present. Attempts at stabilisation were unsuccessful and euthanasia was elected. Post-mortem examination confirmed chronic renal disease of unknown aetiology in addition to an aorto-cardiac fistula originating from the right sinus of Valsalva with subsequent dissection into the basilar interventricular septum.     

Treatment of horses for a facial or oral fistula

A sinocutaneous or nasocutaneous fistula is usually a sequel to a comminuted fracture of one or more facial bones, whereas an oronasal or oromaxillary sinus fistula occurs most commonly after a maxillary alveolus fails to fill with healthy granulation tissue after its tooth has been lost. Horses with a sinocutaneous or nasocutaneous fistula can be treated by covering the fistula with transposed muscle, which in turn is covered by adjacent skin or a free skin graft, or by covering the fistula with periosteum transposed from adjacent bone, itself covered by adjacent skin or left uncovered to heal by second intention. Horses with an oronasal or oromaxillary sinus fistula can usually be treated successfully by temporarily occluding the oral aspect of the fistula, to prevent feed from entering the fistula, until the apical end of the alveolus fills with healthy tissue. Other methods of treatment include covering the oral aspect of the fistula with a mucoperiosteal flap or filling the fistula with a transposed facial muscle.     

Surgical repair and reconstruction of a nasal fistula following intra-lesional formalin injection

A 6-year-old Cleveland Bay mare was referred to the University of Liverpool Equine Hospital for repair of an iatrogenic nasocutaneous fistula. The fistula had developed following attempted ablation of an epidermal inclusion cyst located in the right nasal diverticulum with intra-lesional formalin 6 weeks previously. Subsequent tissue necrosis resulted in the formation of a full-thickness defect in the overlying tissues and the creation of a 5 × 5 cm nasocutaneous fistula. Surgical management consisted of initial debridement of the fistula and use of a commercial dermal regeneration mesh to bridge the defect, acting as a tissue scaffold. The levator labii superioris muscle was utilised to cover the scaffold by transecting it close to its proximal origin and reflecting it rostrally. Finally, a transposition skin flap was created adjacent to the site and was rotated to cover the defect. The mare made an excellent recovery, and follow-up confirmed complete healing of the surgical site with an excellent cosmetic outcome.     

Transmaxillary anchored silicon embedded gauze plug in the post-operative treatment of a large oromaxillary fistula caused by a supernumerary cheek tooth

A 9-year-old Hungarian sport horse gelding was presented to the clinic in poor condition displaying malodorous bilateral purulent nasal discharge. Oral examination revealed the presence of supernumerary 111 and 211. Bilateral diastema formation between the third maxillary molars and the supernumerary teeth with deep periodontal pockets and massive food impactions were diagnosed endoscopically. Radiography revealed inhomogenous sinus opacities in the left and right paranasal sinuses. Following bilateral oral extractions of the supernumerary cheek teeth and third maxillary molars, bilateral oromaxillary fistula formations were diagnosed (about 17 mm diameter on the right side). Bilateral frontal and right-sided maxillary trephinations and resection of the right bulla of the maxillary septum were performed. Massive food impactions of the left and right paranasal sinuses were removed under endoscopic control. Repeated trans-endoscopic sinus lavage was performed post-operatively. After 2.5 months, the large right-sided oromaxillary communication was temporarily closed with a transmaxillary anchored, gauze-cored silicon plug on an outpatient basis. Follow-up examination after 187 days revealed complete closure of the oromaxillary fistula and absence of sinusitis. In a 1.5-year follow-up control, no pathological conditions were found.     

Treatment of chronic septic osteoarthritis of the antebrachiocarpal joint with a synovial‐cutaneous fistula utilising arthroscopic lavage combined with ultrasonic assisted wound therapy and vacuum assisted closure with a novel wound lavage system

This case report describes the successful management of a chronic multidrug resistant infection of the antebrachiocarpal joint with a synovial‐cutaneous fistula 7 weeks after initial trauma in a 14‐year‐old Icelandic stallion. Resolution of the multiresistant Enterobacter cloacae (extended‐spectrum β‐lactamase) infection from the joint and complete closure of the fistula was achieved by arthroscopic lavage under general anaesthesia repeated on 3 occasions, surgical debridement, ultrasound assisted wound therapy and vacuum assisted closure. Lavage of the wound with the vacuum assisted closure in place was facilitated via the novel VeraFlo instillation system consisting of specially designed therapeutic regulated accurate care pad tubing. The combination of these therapies resulted in resolution of the septic arthritis and fistula. Six weeks after admission the horse was discharged from the hospital with a completely healed wound and was not lame at a walk.     

Surgical management of an enterocutaneous umbilical fistula caused by an incarcerated Richter's hernia in a one-year-old Quarter Horse filly

This article reports a case of a one-year-old Quarter Horse filly with an enterocutaneous fistula resulting from an umbilical hernia since birth, treated successfully by en bloc resection of the hernial sac with the fistula and closure of the ileum with a modified Heineke-Mikulicz technique. This consisted of closing the intestinal wound transversely to the long axis after excision of the fistula to help preserve a sufficient intestinal lumen and prevent potential stricture formation after longitudinal closure. Umbilical hernias are reported to have an incidence of 0.5–2.0% usually resolve spontaneously. Reducible hernias do not represent a surgical emergency whereas incarcerations should always undergo surgery as soon as possible. Enterocutaneous fistulae occur uncommonly as a result of congenital umbilical herniae that developed spontaneously into Richter's herniae or Littré herniae or they are induced traumatically or iatrogenically after therapeutic attempts. In most cases, enterocutaneous fistulae do not require immediate surgery. However, the excision of the fistula should be scheduled within a few days after diagnosis. In the current case, the owner reported a healthy development of the filly after 1 year without any functional problems. This case represents an example of successful use of the Heineke-Mikulicz technique to establish an alternative to standard end-to-end anastomosis.