Severity assessment in pigs after partial liver resection: evaluation of a score sheet

Severity assessment in biomedical research is required by the European authorities. Therefore, a variety of score sheets are available. The first score sheets were designed and introduced by Morton and Griffith (M&G) in 1985, to assess pain and distress in animals. Score sheets are an important part of the 3R principles to evaluate the degree of severity in different studies. Here, we used a modified score sheet from M&G for severity assessment of 12 Aachen minipigs after partial liver resection for safety testing of a novel synthetic sealant (VIVO-107). The control group was treated with the clinical standard fibrin. Estimation of recovery status of both groups was performed from the day of surgery to postoperative day 7 using a score sheet. Included parameters were blood loss during the surgical procedure, general state, spontaneous behaviour and clinical results. Values from 0 to 20 were graded for each category and resulted in the degree of strain (DS) from DS0 to DS4. An increasing DS indicated higher severity. Suitability of the implemented score sheet was evaluated. Higher score points were documented almost exclusively as an outcome of the clinical results, influenced mainly by increased temperature in the fibrin treated control group, whereas, spontaneous behaviour had only slight influence and general state had no influence. The average score seven days after surgery was <2. The laparotomy, where the partial liver resection is a part, is rated as moderate severity in the EU Directive 2010/63, while the assessment done in the present study hints to a mild severity of the model in our hands.