Analysis of applications and outcomes of minimally invasive surgical techniques in wildlife

Student thesis: Doctoral thesis


Minimally invasive surgery (MIS) is currently regarded as the gold standard for many human surgical procedures, and has also been demonstrated to benefit domestic animal veterinary patients for several procedures. Many of the benefits of MIS, well established in the evidence base for human surgery, could have particular application in wildlife veterinary surgical patients, but despite the fact that the first non-domestic animal MIS procedures were performed almost 50 years ago, demonstration of its advantages over open surgery remains fragmented and mainly low-level evidence. The first objective of this doctoral thesis was to establish the quality and scope of published peer-reviewed literature abstracts forming the current evidence base for all types of surgery in wild animals, as well as establish published complication rates. A total of 635 abstracts, containing a total of 6582 individual animals were included. The majority were single case reports at 59. 69%, with only 15. 19% of publications contained 10 or more animals. The complication rate calculated from summation across all papers was 5. 67% (95% confidence interval [CI] 5. 12-6. 24%, standard error [SE] 0. 28%). The next objective was to compare the outcomes between MIS and open surgical procedures in wildlife in the current peer-reviewed published literature. A systematic review, with indirect comparison meta analysis, evaluated complications between open surgery and MIS in wildlife. 243 individual studies met the search criteria for open or MIS surgery of the abdomen or coelomic cavity in wildlife species, of which only 50 studies included 10 or more individuals. Only two publications directly compared MIS and open surgery, and the direct meta analysis results, while appearing to favour MIS, were not statistically significant. Individual patients and reported complications were summated, to estimate total published complication rates. Across all wildlife species a 6. 54% absolute risk reduction (95% CI of the difference 5. 08-8. 14%, SE 0. 78, p 0. 001) was evident in publications of MIS surgery compared to open abdominal or coelomic surgery. There was a statistically significant lower complication rate across all analysed taxonomic groups, but the evidence was at high risk of bias. Another objective was to compare the outcomes of open abdominal and MIS surgical procedures in captive wildlife species. Surgical records for a 25 year period, were analysed from four zoological collections. Out of a total of 1633 surgical procedures, 361 animals underwent abdominal or coelomic cavity surgery via open surgery or MIS. Across all species, open surgery carried a major complication rate of 26. 35%, while MIS only carried a major complication rate of 5. 16%; an absolute risk reduction of 21. 19% (95% CI of 13. 69-29. 14%, SE 3. 93%). Published complication rates were notable lower, indicating likely positive publication bias and outcome reporting bias. This needs careful consideration when wildlife veterinarians attempt evidence based surgical decisions. The last objective was to evaluate innate cognitive biases that may predispose to poor surgical decisions in veterinarians operating on wildlife species, and result in adverse surgical outcomes. 57. 14% (95%CI 50. 01-63. 99%, SE 3. 6%) of pre-clinical veterinary students, when self-predicting their surgical skills 5 years after graduation, believed they would be above average, while only 3. 7% (95% CI 1. 81-7. 45%, SE 1. 37%) believed they would be below average. Untrained veterinary surgeons appeared to have an illusory superiority bias, when self-evaluating their surgical aptitude and future surgical performance. Further, only 3. 17% (95% CI 1. 46-6. 75%, SE 1. 28%) ranked clinical auditing as the most important of six suggested options, to improving their personal surgical outcomes once qualified veterinary surgeons. This indicated an innate lack of appreciation or understanding of its value in improving surgical skills and performance.
Date of Award8 Sept 2017
Original languageEnglish
SupervisorLaila Darwich Soliva (Director)

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