Experimental maxillofacial surgery and animal welfare: An objective assessment

Over the years, animals have been used extensively in medical research, including oral and maxillofacial surgery. Experimental surgical procedures impact on the quality of life of the animals involved. It is essential for investigators to address the impact of any proposed experimental procedures on animal welfare. Methods for objective assessment of the impact of experimental oral surgical procedures on animal welfare have not been developed. Objective: To investigate the use of changes in mechanical withdrawal threshold (MWT), the levels of specific inflammatory mediators and body weight peri-operatively for assessing the acute impact of mandibular surgery on animal welfare. Methods: The study was conducted on 12 adult sheep which were undergoing mandibular surgery as part of a research programme in bone bio-engineering. Body weight was measured for 12 weeks, and MWT and haematological tests were carried out one day prior to surgery and daily after surgery for 14 days. Results: Although an overall weight loss at 12 weeks was noted, this was not statistically significant (P-value > 0.05). Compared to the preoperative values, postoperative MWT, and inflammatory mediators were significantly reduced during the first week, but did not concur with the clinical and behavioural changes. Conclusions: The findings suggest that this aspect of craniofacial animal research requires further investigation. Understanding the physiological responses to invasive oral surgical procedures may allow the development of more effective pain control policies and, consequently, an enhanced animal welfare.