EQUINE VETERINARY EDUCATION / AE / SEPTEMBER 2017


483


intervention (Lee et al. 1985). In man, arterial lacerations can be repaired successfully up to 36 h after injury (Gelberman et al. 1982) with those arising from blunt trauma ideally repaired in less than 12 h (Sturm et al. 1980). Arterial forearm injury in man treated by arterial repair has a patency of 85.7% at 6 months post operatively (Lee et al. 1985) with less wound complications reported when the artery is repaired rather than ligated (6 vs. 36%). During arterial anastomosis, it is recommended that the


outermost layer of the artery, the tunica adventitia, is dissected away from the cut end of vessels to avoid inadvertent infolding of the adventitia into the lumen of the anastomosis (Philips and Aronson 2012). Inclusion of the adventitia would reduce luminal diameter and obstruct blood flow and possibly lead to thrombus formation (Sackman 2002). In the current case, the fragile tunica adventitia had already been separated from the innermost 2 layers, possibly due to the traumatic nature of the laceration and hence this layer was closed in a separate layer for added protection of the anastomosis. The risk of systemic anticoagulant medication must be


carefully considered before administration and was not implemented in this horse due to the marked blood loss. The most commonly used anticoagulant medication used in human medicine is aspirin. Recommended doses of aspirin include 5 mg/kg bwt every 48 h to 100 mg/kg bwt every 24 h (Plumb 2005) since aspirin has been shown to have an antithrombotic effect in the horse at doses from 4 mg/kg bwt (Cambridge et al. 1991). The prolonged effect of aspirin on platelet function has been documented despite a very short plasma half-life due to its irreversible action on platelet cyclooxygenase and is therefore recommended at 48 h interval administration (Cambridge et al. 1991). Other recommendations to prevent thrombus formation include intraluminal flushing of the 2% lidocaine, heparin or 0.9% saline (Philips and Aronson 2012). The latter intervention was used in the current case to prevent thrombus formation at the anastomosis site. Monofilament suture such as polypropylene is recommended for arterial suturing due to its greater strength, durability and decreased tissue reactivity. Despite this, a braided multifilament suture is often chosen over a monofilament suture because of its excellent knot holding and better handling properties (Rutherford 2005). Polyglactin 910, a multifilament suture, was used in the case described currently for these reasons listed above. Previous reports of successful experimental microvascular


surgery in horses have been published (Turner 1985) and canine models of arteriovenous injury have been used to study haemodynamic perturbation following repair (Nazzal et al. 1994). To the authors’ knowledge there are no reports describing successful repair of a major digital vessel in a clinical case and little detail is available regarding arterial repair technique in standard equine surgical textbooks. This case report details the successful arterial anastomosis and return of haemodynamic function following complete laceration of the medial digital artery in a horse. The authors propose that arterial repair, rather than ligation, should be considered whenever possible and particularly in traumatic lacerations with clean arterial margins thus suitable for repair.


Authors’ declaration of interests No conflicts of interest have been declared.


Ethical animal research


The owner of the horse in this case report provided ethical consent for use of case details.


Source of funding None.


Authorship Both authors contributed to the preparation of the manuscript and have approved the final version.


Manufacturers' addresses


1MSD Animal Health, Milton Keynes, Bucks, UK. 2Dechra Veterinary Products Limited, Shrewsbury, Shropshire, UK. 3Smith and Nephew Medical Ltd, Hull, Yorkshire, UK. 4Robinson Healthcare Ltd, Worksop, Nottinghamshire, UK. 5Millpledge, Retford, Nottinghamshire, UK. 6V


etoquinol UK Ltd, Buckingham, UK.


7Hameln Pharmaceuticals Ltd, Gloucester, UK. 8Boehringer Ingelheim Limited, Bracknell, Berkshire, UK. 9Wockhardt UK Ltd, Wrexham, UK. 10Martindale Pharmaceuticals, Romford, Essex, UK. 11Vygon, Ecouen, France.


References


Cambridge, H., Lees, P., Hooke, R.E. and Russell,C.S. (1991) Antithrombotic actions of aspirin in the horse. Equine Vet. J. 23, 123-127.


Dyce, K.M., Sack, W.O. and Wensing, C.J.C. (Eds) (2002) Chapter 23: the forelimb of the horse. In: Textbook of Veterinary Anatomy, 3rd edn., WB Saunders Co., Philadelphia, London. p 598.


Gelberman, R.H., Nunley, J.A., Koman, L.A., Gould, J.S., Hergenroeder, P.T., MacClean, C.R. and Urbaniak, J.R. (1982) The results of radial and ulnar arterial repair in the forearm. Experience in three medical centers. J. Bone Joint Surg. Am. 64, 383-387.


Lee, R.E., Obeid, F.N., Horst, H.M. and Bivins, B.A. (1985) Acute penetrating arterial injuries of the forearm. Ligation or repair? Am. Surg. 51, 318-324.


Nazzal, M., Bove, P.G., Harris, J.A., Bendick, P.J. and Glover, J.L. (1994) Hemodynamic sequel of combined arteriovenous injury in an experimental canine hindlimb model: venous ligation. Ann. Vasc. Surg. 8, 166-171.


Owen, K.R., Singer, E.R., Clegg, P.D., Ireland, J.L. and Pinchbeck, G.L. (2012) Identification of risk factors for traumatic injury in the general horse population of north-west England, Midlands and north Wales. Equine Vet. J. 44, 143-148.


Philips, H. and Aronson, L.R. (2012) Vascular surgery. In: Veterinary Surgery Small Animal Volume 2, Eds: K.M. Tobias and S.A. Johnston, Elsevier, Missouri. pp 1854-1869.


Plumb, D.C. (2005) Plumb’s Veterinary Drug Handbook, Ed: I.A. Ames, PharmaVet, Stockholm. pp 508-510.


Rutherford, R.B. (2005) Diagnostic evaluations of arteriovenous fistulas and vascular anomalies. In: Vascular Surgery, 6th edn., Ed: R.B. Rutherford, Elsevier Saunders, Philadelphia. p 1602.


Sackman, J. (2002) Principles of vascular surgery. In: Textbook of Small Animal Surgery, 3rd edn., Ed: R.B. Rutherford, W.B. Saunders, Philadelphia. p 996.


Stashak, T.S. and Theoret, C.L. (2013) Integument system: wound healing, management and reconstruction. In: Equine Emergencies, Treatment and Procedures, 4th edn., Eds: J. Orsini and T. Divers, Elsevier, Missouri. pp 238-267.


Sturm, J.T., Bodily, K.C., Rothenberger, D.A. and Perry, J.F. Jr (1980) Arterial injuries of the extremities following blunt trauma. J. Trauma 20,933-936.


Turner, T.A. (1985) Arterial grafting in the horse: an experimental study. Vet. Surg. 14, 15-20.


© 2016 EVJ Ltd


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