Medical Grade Honey prevents surgical site infections

Abdominal surgery is a major undertaking in horses, and not without significant risks to the patient. Colic operations, especially those that involve opening the gut wall, risk contaminating the wound with bacteria such that surgical site infection (SSI) is a potential complication.

Medical grade honey (MGH) has been used successfully to treat established infections in both humans and animals, and has been shown to improve wound healing of equine lacerations and significantly reduce infection rate.

 

Would the application of MGH help abdominal surgical wounds to heal?

 

A study by Gustafsson and colleagues investigated whether medical grade honey gel, applied on the linea alba during wound closure, would decrease the prevalence of incisional infections in horses undergoing colic surgery.

 

Figure 1: Example of intra-lesional application of
L-Mesitran Soft (MGH) following colic surgery

The linea alba is the fibrous band that runs along the midline of the belly, between the abdominal muscles.  Being composed of fibrous connective tissue it contains no major blood vessels making it a suitable site for incisions for abdominal surgery.

 

In this prospective randomized controlled trial, 108 horses that underwent colic surgery at Koret School of Veterinary Medicine in Israel were enrolled. Horses were randomized to control or treatment (MGH) group. In the treatment group, following closure of the linea alba, MGH gel (L-Mesitran Soft) was placed in the incision followed by routine closure of subcutaneous tissue and skin (Figure 1).

 

Horses were excluded from the study if they needed a second abdominal surgery (n=4) or did not survive for at least two weeks post-operatively (n=15).

 

The clinicians report that a single intra-incisional application of MGH gel strongly reduced incisional infection rate from 32.5% (13/40) in the control group to 8.2% (4/49) in the treatment group (p=0.02).

 

No adverse reactions were observed with the subcutaneous application of MGH after colic surgery.

 

A full report is published in the Equine Veterinary Journal.

 

The authors conclude that intra-incisional application of MGH gel on the linea alba is a simple and rapid procedure that was safe and did not result in any adverse effects. A single local prophylactic treatment with MGH in the abdominal incision during surgery significantly decreased the prevalence of incisional infections in horses undergoing colic surgery. They suggest that more research is necessary to explore this promising approach in indications outside the equine colic field, e.g., in surgeries with a high risk of SSIs.

 

For more details, see:

 

Intra‐incisional medical grade honey decreases the prevalence of incisional infection in horses undergoing colic surgery: a prospective randomised controlled study.

Gustafsson, K., Tatz, A.J., Slavin, R.A., Sutton, G.A., Dahan, R., Abu Ahmad, W. and Kelmer, G.

Equine Veterinary Journal (2020)

https://doi.org/10.1111/evj.13407

 

An interview with Dr Gustafsson is available on YouTube:

https://youtu.be/q2yf7a0f5Ds

Special interest webinars precede National Equine Forum

The National Equine Forum (NEF) will be delivered in a virtual format in 2021. The main Forum, on

Thursday 4^th March, will be preceded by two special interest webinars, to be held in January.

The first webinar “Just in Time – Using Science to Save our Breeds”, (7pm Wednesday 13th January 2021), will be delivered by industry leaders, with opportunities for discussion and questions from the audience.

Chaired by Prof Tim Morris, the webinar will include speakers: Tullis Matson, Simon Cooper, Paul Flynn and Andy Dell.

They will look at the magnitude of the decline of the UK’s native breeds and how their future can be safeguarded. The impact of the extinction vortex on the natural world and how it applies to equine breeds will be covered and the challenging situation of inbreeding in Thoroughbreds explored.

The advantages of DNA analysis will be debated, to show how science can provide breed societies and breeders with support to guide decisions that can increase effective populations. This will be endorsed with a case study to show proof of concept that breeds in decline have a chance to be saved when genomics and kinship analysis are utilised.

The second webinar “Great Weight Debate (equine)”, (7pm Wednesday 27th January 2021), will take a practical look at different perspectives on equine weight management, from across the equestrian sector, including the views of a horse owner, livery yard owner and coach, an equine welfare officer, an equine vet, a nutritionist and a competition judge.

The panel of speakers will aim to identify what is preventing owners/carers from managing horse weight effectively, despite many previous and ongoing attempts from industry to effect change. They will also explore how any obstacles may be overcome and the discussions will be supported by a human behaviour change researcher.

The 29th National Equine Forum, themed Positivity and Progress will be held on Thursday 4th March 2021. The morning session will provide critical insight to welfare, trade and biosecurity, followed by positive innovations for the sector, borne from Covid-19. The afternoon session will provide updates from the two special interest webinars, a session on how new technology is helping riders and a revisit to access and accidents, with amendments to The Highway Code.

Tickets are priced at £5.00 for each webinar and £10.00 for the Forum itself and there is no booking fee. Webinar tickets are available now. NEF tickets will be available in January.

For more details, see:

https://www.nationalequineforum.com/forum-2021/

CT best for identifying foot foreign bodies

 Puncture wounds at the coronary band or in the sole are not uncommon in horses.  Although the site of

the injury may be obvious, it is often less clear whether any foreign material remains buried in the wound.

Researchers at the Philip Leverhulme Equine Hospital, University of Liverpool, conducted a study to compare the value of different imaging techniques for identifying foreign bodies in horses’ feet.

Nadine Ogden and colleagues assessed the ability of three equine veterinarians, experienced in advanced imaging interpretation, to identify foreign bodies buried in the cadaver specimens of horses’ feet. They used five different materials: slate, glass, dry wood, soaked wood and plastic. Each foot had two different foreign bodies implanted, at the coronary band and in the sole.

Computed tomography (CT), magnetic resonance imaging (MRI) and digital radiography (DR) were used to obtain images, which were then examined by the clinicians.

The researchers found little variation between the clinicians studying the images. CT was the most useful imaging modality, having a higher visibility score, sensitivity/specificity, and interrater agreement for detection of all materials; particularly slate, glass, and dry wood, compared to the other imaging modalities.

They found that foreign bodies were often visible on MRI, although the images were generally not clear enough to determine the type of material involved. They also  found that even relatively large foreign bodies consisting of plastic or wood were not detectable on DR.

The work is published in Veterinary Radiology and Ultrasound. The authors comment that although it is not usually necessary to identify the specific material involved, it is important to select an appropriate imaging technique to detect the suspected foreign body.

They suggest that, in cases with negative findings on MRI and DR, where there is a suspected foreign body within the hoof, particularly in cases where plastic or wood fencing or glass materials have been found at the scene of injury, CT examination should be considered.

 

For more details, see:

CT more accurately detects foreign bodies within the equine foot than MRI or digital radiography

Nadine K E Ogden, Peter I Milner, John D Stack, Alison M Talbot

Vet Radiol Ultrasound (2020)

doi: 10.1111/vru.12944

Temperature monitoring with microchips

 Horses undertaking strenuous or prolonged exercise in hot and humid environments may produce heat

more quickly than they can lose it, putting them at risk of postexercise exertional heat illness.

 Investigations into heat production and cooling require a way to monitor body temperature. Ideally this should be easy and safe to do in an excitable horse after exercise.

 In practice, reading the rectal temperature with a thermometer is a common starting point – but may not be ideal, particularly if repeated readings in excited horses are required. The “gold standard” for monitoring is to record the central venous temperature (CVT) using a thermocouple introduced into the jugular vein.  

 Temperature sensitive microchips (percutaneous thermal sensing microchip (PTSM)) can be used to measure tissue temperature in a non-invasive manner. But does the site of implantation affect the accuracy?

 Researchers at the School of Agriculture and Food Sciences, and the School of Veterinary Science, at the University of Queensland, investigated the use of PTSMs for monitoring temperature in horses after strenuous exercise.

 Microchips used for identification purposes are generally implanted in the nuchal ligament in the neck. In a preliminary study, the research team found that temperature recorded by a PTSM chip implanted in the nuchal ligament correlated poorly with the CVT during and immediately after exercise. This was probably due to the poor vascular supply of the nuchal ligament compared to other muscles, they suggest.

 The researchers also found poor correlation between rectal temperature and CVT immediately after exercise and for at least 8 min after exercise. Because of this, and for safety reasons, they suggest that rectal temperature should not be used to measure temperature after exercise.

 Of the implantation sites they tested, they found that the most reliable was the pectoral muscles, which closely matched the CVT, followed by the gluteal muscles and the splenius muscle.

 They conclude that PTSMs provide a simple, safe, quick, accurate, and non-invasive way of measuring body temperature of horses immediately after high-speed exercise. They recommend further studies to validate this method under field conditions and in equine athletes working in extreme environments and intensive activity in various equestrian sports.

 

For more details, see:

 The Use of Percutaneous Thermal Sensing Microchips for Body Temperature Measurements in Horses Prior to, during and after Treadmill Exercise

Hyungsuk Kang, Rebeka R Zsoldos, Solomon M Woldeyohannes, John B Gaughan, Albert Sole Guitart 

Animals (Basel) (2020) ; 10(12):E2274.

doi: 10.3390/ani10122274

Does pain affect Cushing’s test?

 

Research suggests that mild to moderate pain does not interfere with the hormone tests used to diagnose PPID.

A diagnosis of PPID (pituitary pars intermedia dysfunction, also known as Cushing’s Disease) can be supported by assessing the ACTH levels at rest and by measuring the response to a TRH (thyrotropin-releasing hormone) stimulation test.

In PPID, the over-active pituitary gland secretes higher than normal amounts of ACTH and other hormones. But pain itself may also cause increased ACTH levels.

Many horses with PPID eventually develop laminitis. Indeed, many are first suspected of having PPID when they show signs of laminitis. 

Does the pain associated with laminitis affect the value of ACTH as a diagnostic test for PPID? Heidrun Gehlen and colleagues at the Equine Clinic, and the Institute of Veterinary Epidemiology, Freie University Berlin, Germany conducted a study to investigate.

Fifteen horses being treated at the Equine Clinic for colic, laminitis or orthopaedic conditions with low to moderate intensity pain were included in the study. Horses were aged less than15 years, with no signs of PPID.

Samples were collected for basal ACTH concentrations, and a TRH-stimulation test was performed.

The intensity of pain was assessed using a composite, multifactorial pain scale. Each horse served as its own control as it was re-tested after the pain had subsided.

The researchers found no significant difference in the ACTH concentration in horses with pain and the controls, between different pain intensities or between disease groups.

They conclude that “measuring the basal ACTH concentration and performing the TRH stimulation test for the diagnosis of PPID seem to be possible in horses with a treated low to moderate pain condition.”

They suggest that “measurement of ACTH and the performance of the TRH stimulation test for PPID diagnostics can, therefore, be performed on horses in pain as long as they are not suffering from massive pain or showing a significantly disturbed general condition.”

For more details, see:

Can Endocrine Dysfunction Be Reliably Tested in Aged Horses That Are Experiencing Pain?

Heidrun Gehlen, Nina Jaburg, Roswitha Merle, and Judith Winter

Animals (Basel). (2020); 10(8): 1426.

doi:10.3390/ani10081426

Understanding ridden horse behaviour – Free webinar from World Horse Welfare

In this free webinar, Dr Sue Dyson shares some of the research that has looked at signs and behaviours horses display when they are experiencing pain, many of which can be very subtle.

She also discusses the sensitive issue of the impact of rider size on equine performance. Sue explains the influence that riders can have on their horses and what we, as owners, can do to ensure we are able to assess and recognise signs of discomfort and pain as soon as possible.

Webinar: Recognising pain in our ridden horses and the impact of rider weight - YouTube