July_95_Vet_Forum_Owner Breeder 26/06/2012 14:58 Page 76
VET FORUM: THE EXPERT VIEW By DEIDRE CARSON BVSc (Sydney), MRCVS
Surgery in the horse: don’t take it lying down The risk posed by anaesthesia makes standing surgery advantageous where possible their muscles and limb nerves can become compressed by recumbency, and their sheer physical size makes safe recovery from general anaesthesia more problematic. Advances in anaesthetic protocols and methods, such as blood pressure monitoring and support, assisted ventilation, continuous intravenous fluid administration and specifically designed and constructed surgical tables have helped to reduce, but not fully eliminate, these problems.
What is the greatest risk of anaesthesia? Limb fracture during recovery from anaesthesia is the most common and the most devastating complication of anaesthesia in horses and is most often seen after fracture repair or colic surgery. Safer rope-assisted recovery systems are now commonly used to reduce the risks of such a catastrophic outcome.
Can we avoid general anaesthesia? Standing repair to a cannon can be performed only on a non-displaced fracture
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quine surgeons constantly review the effectiveness of surgical procedures with the aim of improving techniques, to make use of advances in instrumentation, to reduce trauma and stress and to provide the optimum outcome for horse and owner. Owners and insurance companies always want cheaper but equally or more effective treatment options with reduced risk of complications either during or after the procedure. There have been significant improvements in diagnosis, particularly of stress fractures and functional respiratory problems, and treatment options are required to keep up where possible. We must remember that, relatively speaking, the horse is a large animal – the average thoroughbred weighs approximately 500kg and stands about 16hh (about 5ft 4in or 163cm), and broodmares and stallions are often heavier. The large size of the equine patient compared to their human and small animal equivalents creates significant disadvantages when surgery is performed.
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Specialised facilities and equipment are required and trained and experienced surgeons and support staff are also a prerequisite to handle and operate successfully on our equine friends, who may be very valuable or much loved and can be difficult and uncooperative. Horses are also unpredictable and potentially dangerous to themselves and hospital staff, especially when in pain. They find change to their routine, including travel, stressful. In terms of their physiology, horses are not designed to spend long periods lying on one side or their backs under general anaesthesia. Equine mortality during and following general anaesthesia is significantly higher than in human or small animal patients undergoing similar procedures. There are a variety of reasons why anesthetised equine patients present particular difficulties, including interference with respiration and circulation brought on by the medicines used to induce and maintain anaesthesia. Additionally, owing to their weight,
Over the past few years, an increasing number of surgical procedures have been performed on standing, sedated horses. Given the risks discussed above and the increased costs associated with surgery under general anaesthesia, there are significant advantages to be gained if a procedure can be performed effectively on standing patients. However, there are some important
Cases must be chosen carefully Important factors to consider include: • Temperament of the patient • Type of fracture or condition to be treated • Facilities and equipment available • Experience and skill of the surgeon and support staff • Post-operative care
THOROUGHBRED OWNER & BREEDER INC PACEMAKER