In our surgery we carry out a wide range of elective procedures, including arthroscopy, joint flushes, plantar neurectomies, fracture treatment, castration, removal of retained testicles (rigs), penile amputations & ureterostomies for penile problems, and many others.
We do both standing surgery under sedation for certain procedures as well as general anaesthetics for more invasive and complicated operations.
Plantar neurectomy (for suspensory ligament damage)
For standing sedation an intravenous cannula is used to allow “Constant Rate Infusion” (CRI) of sedative. This allows a constant low-level “drip-drip” of sedative rather than a larger amount (bolus) every half-an-hour or so, leading to a better level of sedation. This allows the operation to be carried out much easier and more reliably.
At Heaps Cottage Equine Clinic we carry out many sorts of surgery. Obviously in view of Simon Constable’s Certificate in Equine Surgery (Orthopaedics), a larger proportion of these are related to orthopaedics.
Many of these surgeries are carried out under general anaesthetic although it is becoming increasingly common to carry out standing surgery using the latest in sedation, local anaesthetic techniques and drugs.
These procedures are carried out with the horse in the stocks to prevent them walking off or moving too much. Commonly a sedative is used to make the patient less likely to react although if they are very co-operative, this may not be necessary. A good technique is that of Constant Rate Infusion (CRI) where a catheter is placed in the horse’s jugular vein to allow a saline drip containing sedative to be run in a-drop-at-a-time. This allows a gradual, slow and more controlled sedation that can be altered quickly if necessary rather than a large bolus or dose of sedative at the start.
Examples of standing surgeries we have carried out include neurectomy of the palmar digital nerves in the feet (“de-nerving”), enucleation (removing the eye), sinus surgery (flushing or debriding), skull fracture repairs and laparoscopy (keyhole abdominal surgery to remove ovarian tumours).
General Anaesthesia (“GA”)
A general anaesthetic is when the horse is completely “knocked out” or unconscious. It is a more dangerous procedure than standing surgery because of the larger risk of complications. Although a great deal of care is taken when doing this, there can be a death rate as high as nearly one in a hundred. This figure does include all types of surgery including more demanding and longer procedures on very sick horses, but it can be seen that the risks are quite high in horses.
The reason for such a high figure is related to the large size of a horse and the temperament (their tendency to panic as a “flight animal”). This behaviour where a horse may panic is known as “the flight response” and, in the wild, occurs when a predator is chasing the prey animal. When recovering from anaesthetic, the horse may be confused or disorientated and this may result in an attempt to get up from the ground too quickly. Therefore, we routinely sedate horses in the recovery box to help reduce the risk of this reaction. There is always a risk with every GA in any animal or human but this risk is higher in horses than many other species mainly because of their size and temperament.
There are risks at all times throughout the anaesthetic although the induction and recovery are particularly high. Injuries such as fractures can occur after any procedure although the longer the procedure, the greater the risk.
General anaesthetic procedures are reserved for situations that require the horse to be completely immobile such as arthroscopy where a camera is placed into one or more of the joints.
General anaesthesia (GA) requires the horse to be brought into the clinic the night before to ensure that a period of starvation prior to surgery occurs. It is important that all horses have their shoes removed before a GA can be carried out; this is to reduce the risk of injury when the horse is induced, when on the surgery table and on recovery.
The morning of the GA, patients are prepared in our stocks area, before being moved to a specially padded “induction” room, where they can be safely anaesthetised. Once under anaesthetic, they are placed on a surgical table, which is an inflatable bed padded with air. This lowers the chance of complications such as muscle damage/cramps from the anaesthetic and lying in the same position for prolonged periods of time.
The anaesthetic monitoring is always done by a veterinary surgeon although Mike is our main anaesthetist. We have ECG, pulse oximetry and blood pressure monitoring to ensure the procedure is as safe possible.
After the surgery the patient recovers in our padded recovery room and is given a sedative and often fluids to maintain blood pressure.
We carry out a wide range of elective procedures, including arthroscopy, joint flushes, plantar neurectomies, fracture treatment, castration, removal of retained testicles (rigs), penile amputations & ureterostomies for penile problems, and many others.
Surgery carried out under general anaesthesia
Arthroscopy (keyhole surgery of the joints) is regularly carried out for diagnosis and treatment of joint problems. The most common condition treated in this way is OCD (Osteochondritis dissecans) which is a joint problem where the bone beneath the cartilage doesn’t mature properly and there is a weakness in this “scaffolding”. This frequently means that an area of cartilage can lift up forming a flap; also this flap can become detached to for a floating piece of cartilage called a “joint mouse”.
As could be imagined this can irritate the joint in a similar way that a stone can cause pain when lodged in a shoe. Removal and “tidying up” of the joint is the best treatment. In the process of keyhole surgery a small incision is made through which the camera is placed inside a cannula or tube. At another site in the joint another incision is made through which the instruments are passed. These instruments are used to grab any fragments such as joint mice and debride any roughened area of the cartilage caused by the fragments. The joint is flushed with sterile saline to remove any further debris and then the small incisions sutured.
Other types of surgery we do under general anaesthetic include castrations in stallions of colts older than 2 years old. These have to be carried out under general anaesthetic to ensure that the “cord” can be tied off to ensure that there is no bleeding and to prevent the possible herniation of intestines through the castration wounds (that could occur if this procedure was carried out under standing sedation).
Rig castrations are also done this way. A rig is when one or more testicle is retained either in the groin area or occasionally in the abdomen. Often the ones in the groin can be castrated through a normal incision but the ones retained in the abdomen are more complicated and involve a separate incision into the abdomen to retrieve the testis. This is a much more complicated procedure and may prolong the procedure by some time.
Umbilical hernia repairs need the horse to be under general anaesthetic. Penile amputations and the more severe cases when the whole penis and sheath need to be removed along with a new opening between the back legs must clearly be done under GA. These techniques are usually used for the treatment of squamous cell carcinoma tumours of the penis.
Preparation for GA
A horse needs its shoes removed prior to general anaesthetic because of the risk of injury to itself or to the vets when the horse is unconscious. This is generally done by the client’s farrier before arriving at Heaps Cottage although we are able to do this if necessary.
The horse is always starved overnight to prevent stomach contents from refluxing back up into the horse’s throat and risking entering the lungs. Also water is taken of them prior to surgery.
Often we will clip an area in readiness for surgery although some horses need to be done whilst under the anaesthetic!
Commonly we keep a horse in at least 24 hours after surgery to ensure complete recovery. This also allows us to monitor food and water intake as well as urine and faecal output. It also gives us chance to examine any wounds or incisions that have been made and to repeat any bandaging that may be required.
It is important to ensure that any instructions given after the surgery are strictly followed to allow the best chance of a successful procedure. As usual we always recommend that clients telephone for advice in any situation where there is doubt or concern. It is one of our maxims that “it is better to ring on a false alarm then not to ring at all!”