Enterectomy may be said to be a hopeless operation in the horse .
The most common and also the most dreaded of horse diseases are those termed colic .
When Professor Barrie Edwards passed away on May 16, 2011, our profession lost a leader and pioneer in colic surgery in a humble and gentle man, whose outward demeanour belied his great accomplishments. I am honoured to be invited to pay tribute to the work of someone that I admire so much in this edition of the Equine Veterinary Journal.
I did not know Barrie as well as I would have liked, but yet I feel that his very pragmatic approach to surgery, built on sound principles and much personal experience, has had a profound influence on me. Those who were so fortunate to work closely with Barrie witnessed first-hand his skills at the surgery table, his legendary enthusiasm for teaching, even in the small hours of the morning, and his ability to inspire great admiration and loyalty from students and colleagues. I was very impressed that Barrie continued to undertake colic surgery to the end of his career and even into retirement, at a time in his life when many others would have spared themselves the early morning calls and loss of weekends.
Barrie's collaborative projects on epidemiological studies into long-term survival after colic surgery in the horse probably earned him the greatest respect from the international audience. Perhaps the very eloquent guest editorial written in the Veterinary Journal in 2008  by Andrew Dart of the Faculty of Veterinary Science, at the University of Sydney, says it best:
‘The University of Liverpool is internationally recognised for expertise in the field of abdominal surgery in horses. Pioneered by Professor Barrie Edwards and perpetuated by Dr Chris Proudman, this research group has been a key contributor to the substantial advances in knowledge of surgical techniques and post operative care that have resulted in an exponential increase in the survival of horses undergoing abdominal surgery over the past 25 years'.
Certainly Barrie Edwards was a pioneer in the field of equine abdominal surgery. He amplified the output from his work through collaboration and he contributed enormously to an improvement in colic survival. To fully understand the magnitude of what Barrie accomplished, we must review the environment from which he transformed colic surgery to its current status.
A prejudice against laparotomy in the horse still exists in the veterinary profession .
Although colic surgery was embraced by some surgeons in the early 1970s, referring veterinarians and owners viewed it largely as a last resort, as a prologue to an imminent death. In a published review of colic in the horse at the time , only 10 of 38 horses with colic were successfully treated by surgery and most of those survivors had minor intestinal procedures. A concluding statement in that study recognised that, ‘although the overall recovery rate was low, the procedure is entirely justified if only as a means of diagnosis’. This was followed by a review of cases at the University of California at Davis from 1958 to 1971, which reported that 48 of 75 horses with small intestinal strangulation (SIS) had surgery and 72.9% died . This was followed by another study from the University of California at Davis on 140 horses that had small intestinal resection between 1968 and 1986 . This study reported that 51% of these horses died during hospitalisation .
A first step in achieving success with any treatment is in identifying causes of failure and this was accomplished in an early study on the incidence, diagnosis and treatment of post operative complications in colic by Judith Hunt and Barrie in 1986 . The authors reviewed 259 surgical cases and demonstrated that post operative ileus and shock accounted for most post operative deaths. This laid the groundwork that underlies current treatments against these devastating and costly complications. This paper also outlined procedures for monitoring post operative progress and post operative treatment regimens widely used today .
Barrie's manuscript on resection and anastomosis of equine small intestine is a must read for all colic surgeons . In a straightforward manner and beautifully illustrated by the author, it describes some of the more common and complex procedures, with insights supported by a wealth of personal experience. The diagrams clearly demonstrate important principles and techniques, such as closure of the mesenteric remnant before the anastomosis, decompression of distended intestine through the transected necrotic section and angling the line of bowel transection to optimise stoma size and perfusion. His paper on 27 horses with intussusceptions also carried Barrie's trademark artwork and astute clinical observations on a challenging surgical lesion . This report also suggested possible predisposing factors for this lesion, such as Anoplocephala perfoliata. A retrospective study of 75 cases of pedunculated lipoma obstruction (PLO) of the intestine was the largest study on this disease at that time . In addition to the obvious age risk, this paper demonstrated a significant increase in risk of PLO for geldings (odds ratio [OR] = 2.32) and ponies (OR = 3.75).
When Barrie demonstrated improved outcomes with colic surgery, progressively more cases were submitted to his care, which spawned a huge data set and resulting seminal epidemiological studies. Examples are 3 consecutive papers published in the Equine Veterinary Journal in 2002 [12–14]. The first of these followed such a large number of horses over a longer period than covered in previous survival studies that it could identify a unique pattern of mortality after surgery . Most deaths were during the immediate post operative period, followed by a lower death rate during the next 100 days and then an even slower decline in survival to the end of the follow-up period. Certain factors were identified that affected survival, including the first account of epiploic foramen entrapment (EFE) as having a negative effect on long-term outcome. Epiploic foramen entrapment was also associated with a greater risk of post operative colic than other strangulating diseases . Risk factors for post operative complications were identified in the third paper, including an association with a high packed cell volume (PCV) at admission, EFE and strangulating lipoma . Most importantly, this paper related complications to their effect on long-term results, which is critical information for those caring for the surgical patient before and after surgery. These were followed in 2005 by a study on an even larger group of horses over a longer period of time that implicated low total plasma protein and longer surgery times for the adverse effect of EFE on survival .
An interest I shared with Barrie and his colleagues in EFE led to 2 papers that we co-authored on an almost inscrutable aspect of this well-known disease [16,17]. I am very proud to have had this opportunity to collaborate with Barrie and the University of Liverpool. It started when I observed that horses that had surgery for EFE would ‘crib’ within 24–48 h after surgery. I commented on this observation to Debbie Archer at the 2002 Colic Research Symposium in Manchester, when I learned that EFE was to be the focus of her graduate studies. She followed up on this and data from the Universities of Liverpool and Illinois were combined to produce 2 publications that lent statistical strength to a stallside observation on the association between cribbing and EFE [16,17]. The University of Liverpool group continued in their studies on EFE and generated sufficient case material to explore a variety of risk factors for EFE, including breed, size and season .
Important issues in surgical technique were revisited and a critical question answered in 2007, when Barrie and colleagues demonstrated convincingly that horses had a significantly poorer long-term survival rate after a jejunocaecal anastomosis compared with end-to-end jejunojejunal anastomosis . Also, the incidence of post operative colic in horses that had side-to-side jejunocaecal anastomoses was greater than in those requiring end-to-end jejunojejunal anastomoses. In those horses that had side-to-side jejunocaecal anastomosis, there was no difference in survival between horses with handsewn vs. stapled anastomoses .
Although all the preceding papers focused on small intestinal diseases, Barrie's interests clearly included all forms of obstructive gastrointestinal diseases. His report on 22 cases of segmental eosinophilic colitis marked an important review of an enigmatic disease, highlighted with clear descriptions supported by beautiful illustrations of different types of large colon resection . An earlier report on small colon diseases addressed treatment of surgical lesions rarely reported before then . The University of Liverpool group also produced what is probably the first report of factors associated with post operative survival following surgery for large intestinal disease . Heart rate and PCV on admission to the hospital, increasing age, resection of intestine and re-laparotomy were all associated with a decreased probability of post operative survival . I so enormously appreciated Barrie's knowledge of large intestinal diseases in horses, his straightforward and careful writing style and highly credible descriptions that I invited him to write a chapter for me in a Veterinary Clinics of North America that I was editing on colic . I was not disappointed and I was very proud of one more opportunity to collaborate with Barrie.
I developed a high regard for Barrie's attention to detail and strong commitment to his patient's well-being when Richard Coomer and others designed a case-based study to determine if subcutaneous sutures would increase the risk of suppuration from the laparotomy wound . Barrie was rightly concerned because many of the cases would be his and the study design required a group of horses in which the subcutaneous suture would be omitted. I had abandoned this closure layer many years earlier and was therefore consulted about the wisdom of such a design. I was to provide some assurance to Barrie that his patients would not suffer from omission of the subcutaneous suture and was very relieved that the lack of this layer had no effect on outcome .
The paper that best exemplifies Barrie's great success with colic surgery and the strength of the collaboration he had established with colleagues was an epidemiological investigation on a staggering number of 1014 horses undergoing surgery for colic over a 16 year period . This work yielded new insight into factors underlying adhesion formation, specifically that adhesions were no more prevalent after surgery for a small intestinal lesion compared with a large intestinal lesion and could affect a segment of the abdomen distant to the primary lesion. Also adhesion formation was consistent with the hypothesis that surgical trauma is the most important cause of this complication. Therefore pan-abdominal, rather than site-specific measures should be used in all horses that undergo exploratory laparotomy. The most impressive aspect of this large-scale study was the very favourable long-term survival in these horses, with a median survival time of 2000 days after one surgery and 1200 days after a repeat celiotomy .
Barrie's curriculum vitae is a powerful testimonial to the awards he has received and the highly prestigious international conferences and symposia to which he was invited throughout his career. Although too numerous to list, they collectively provide a strong measure of the respect he earned from colleagues around the world. He participated in meetings in at least 12 countries outside the UK, including the very prestigious Bain-Fallon Memorial Lectures in Sydney, Australia. He was a regular attendee and speaker at the International Symposia on Colic Research, which is the venue that allowed most of us in the USA to gain from his wisdom and insights. He was also a visiting lecturer in the UK and around the world, including universities in Australia, Iran, Zimbabwe and Chile. He was obviously much sought after as an editor, for this journal and for others.
Barrie received many awards throughout his career, but the last that he received was the British Veterinary Association's most prestigious scientific award, the Dalrymple-Champneys Cup and Medal. It was given to Barrie for his seminal contributions in the field of equine abdominal disease and surgery and for his brilliance as a surgeon and educator . Other notable awards and achievements include a CBE (2003), D.Vet.Med. University of London (1991), F.R.C.V.S. (1993), the Richard Hartley Memorial Literary Award from the Equine Veterinary Journal (twice, 1978 and 1981) and the Equine Veterinary Journal Open Award (1986). Barrie gave the Hobday Memorial Lecture for BEVA in 1995 and received the Animal Health Trust Outstanding Scientific Achievement Award in 1996. He was President of the British Equine Veterinary Association in 1995, was a Member of Council of Royal College of Veterinary Surgeons (1988–1996) and became an Honorary Life Member of the Association of Veterinary Teachers and Research Workers 1998. He received the Victory Medal from the Central Veterinary Society in 1993.
Barrie Edwards has left us with a legacy that will survive for years to come through an improved confidence in colic surgery and a colic database for credible epidemiological studies on colic. He developed a team of colleagues that can expand on his legacy. Although much has been written and spoken about Barrie Edwards' impact on colic surgery in the horse, in truth, the greatest benefactors of his work are those that can only praise his efforts by silently enjoying the benefits of them. As veterinarians, we should regard that as the ultimate praise.