Received: 27 February 2023 | Accepted: 15 January 2024 DOI: 10.1111/eve.13953_1


C A S E R E POR T


Transposition of the levator labii superioris muscle in two standing horses


Alessandra Fusco 1 | Emanuël K. L. Stas 1 | Tijn J. P. Spoormakers 1 | Stefanie Veraa 2 | Tsjester Huppes 1


1 Department of Clinical Sciences, Equine Surgery Division, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands 2 Department of Clinical Sciences, Diagnostic Imaging Division, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands


Correspondence: Alessandra Fusco Email: a.fusco@uu.nl


SUMMARY


A 14- year- old pregnant Dutch Warmblood mare (Case 1) and a 13- year- old Irish Cob mare (Case 2), presented with chronic purulent nasal discharge, for 11 weeks and 6 months, respectively, both after oral extraction of Triadan 110. In Case 1, oral inspection revealed a deep nonhealing alveo- lar cavity with bony sequestra. Palpation with a dental probe confirmed an oromaxillary communication. A standing computer tomography (CT) ex- amination of the head showed a defect in the alveolar bone and soft tissue attenuating material extending between the maxillary sinus and oral cav- ity, together with sinusitis of both rostral and caudal compartments of the maxillary sinus and the ventral conchal sinus. In Case 2, oral endoscopy revealed the presence of a ~0.5 cm fistula opening on the buccal mar- gin of the alveolar cavity of Triadan 110, adjacent to the cheek mucosa. Drifting and rotation of the adjacent teeth resulted in a triangular- shaped interdental space with a narrowed access to the alveolar cavity of Triadan 110. CT examination confirmed the presence of an oromaxillary fistula and an extensive sinusitis involving all right sinus compartments. Both horses were initially treated with centesis/flushing of the sinuses, alveolar cavity debridement and placement of a dental plug. After 3 to 4 months, purulent nasal discharge was still present, and oral inspection showed no substantial


improvement. Surgical treatment with transposition of


the levator labii superioris (LLS) muscle was elected. The procedure was performed standing, using sedation and local nerve blocks to avoid risks associated with general anaesthesia and minimise risks for the pregnancy of Case 1. The surgery, except for some modifications, was performed according to the technique described by Brink in 2006. Postoperatively, Case 2 showed signs of right facial nerve paralysis that resolved sponta- neously within 2 weeks. Purulent nasal discharge resolved in both cases. Surgical site infection developed at the buccotomy site in both horses and at the nasal incision used to harvest the LLS in Case 2. However, all


the incisions healed uneventfully and with good cosmetic results. In both cases, serial follow- up oral endoscopic examinations showed a vital mus- cle graft sealing the fistula opening with the intraoral portion of the LLS muscle adhered to the cheek mucosa over the buccotomy site. Long- term follow- up was available for both cases. The complaints did not recur, and transposition did not seem to affect significantly nasal and labial function. The findings of this report confirm that LLS transposition is a valid surgical technique for the treatment of selected refractory cases of chronic oro- maxillary fistulae and that this procedure can be safely and successfully performed in the standing horse using sedation and local anaesthesia.


K E YWORDS horse , fistula , oromaxillary , standing , transposition


Key points


• Transposition of the levator labii superioris muscle is a valid surgical treatment option for selected cases with persistent oromaxillary fistulation, that do not respond to prolonged conservative treatment.


• Transposition can be safely and successfully performed in the standing horse, using a combination of sedation and appropriate local anaesthesia.


• The procedure does not seem to affect nasal and labial function in the long term.


This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2024 The Authors. Equine Veterinary Education published by John Wiley & Sons Ltd on behalf of EVJ Ltd.


340 | aaep.org/wiley-redirect Equine Vet Educ. 2024;36:340.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92