Endoscopy is the technique of using a tiny camera to look inside the body. It is part of what we call “keyhole surgery” of body cavities and joints, and it is also used to image the gut, the uterus, the bladder and other places into which the surgeon can slide the tube with the camera on the end.
The technique has revolutionised veterinary surgery and is widely used in equine practices. Most owners and trainers are familiar with the simple procedure of “scoping” (endoscoping) the throat, larynx and trachea to investigate poor performance or respiratory noises. Many will also know about using a gastroscope to look inside the stomach for ulcers.
But the stomach is about as far as conventional endoscopy can go. In an average thoroughbred-sized horse, a three-metre-long flexible endoscope is needed to reach the stomach. These ’scopes can just about look into the first part of the small intestine beyond the stomach, but definitely no further.
From the other end, little can be achieved by colonoscopy as the colon (large intestine) is not only about six metres long, but is also massive in diameter and filled with many kilos of stodgy contents and fluids. In between the stomach and the rectum is more than 25 metres of small intestine, large colon and small colon — not to mention the caecum, which is a blind-ending o shoot of the bowel about a metre long and very wide.
All conventional endoscopy relies upon the tiny camera being connected to the outside by a thin, flexible, watertight tube, which carries the cables to the camera and to the bright light source built into the tip of the tube. And obviously, the ’scope has to be withdrawn through the same passage into which it was inserted.
Horses suffer from a range of bowel problems, many of which involve the small intestine, but it has been impossible to engineer a conventional endoscope long enough and flexible enough to pass down the throat, through the stomach and into the 20-metre- long small intestine. We have been able to get some information by ultrasound scanning from the outside surface of the belly, but such images give very little detail.
A picture of health
Vets at Calgary University in Canada have just reported the use of an amazing new alternative to conventional endoscopy. A small, sealed capsule — containing a powerful light source, four micro- cameras and a digital chip — can record 360° images as it travels through the bowel, from the stomach to the rectum, and then out in the droppings.
The device, marketed as the Alicam, is about as thick as an AA battery and half the length. It is passed down a tube into the stomach and the horse goes about his routine while the camera takes pictures and video of the surface of the small intestine from the inside. Once it reaches the colon, the volume of the bowel in this section means that images are less useful. It takes between two and four days for the camera capsule to emerge in the droppings.
To begin with, the vets searched the droppings for the capsule, but soon realised that they could simply collect all the dung each day in a plastic tub and X-ray it. The capsule shows up clearly on the X-ray and the process does not affect the digital information.
Once retrieved, the data from the capsule is downloaded to a computer and the journey through the horse can be visualised in detailed full colour. Technology like this has been used in humans for a few years, but its availability to vets is new and very exciting.
Professor Renaud Léguillette, who led the team at Calgary, says: “It’s an easy test to do. It is not invasive, horses tolerate it very well and the images we get back are fantastic, really exceptional.”
The camera capsules are reusable, rechargeable, and the technique requires no sedation, no anaesthetic and no complicated tubes or wires between the patient and the IT system. It is not yet available in the UK, but vets here will be keen to try it out.
Ref: Horse & Hound magazine; 30 May 2019
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