Recommendation for severity assessment following liver resection and liver transplantation in rats: Part I.

Score sheets were first introduced 30 years ago to assess pain, distress and suffering in animals. To date, however, there is still no general agreement on their use in research practice, and only a few publications can be found on this topic. In the present work, we demonstrate the use of a special score sheet for severity assessment in the first three postoperative days in two showcased studies performed on Wistar and Lewis rats undergoing liver resection or orthotopic liver transplantation, respectively. Scoring of different criteria and the total score were evaluated within each intervention. Additionally, both procedures were compared regarding their degree of severity. Suitability of these score sheets was evaluated for assessing severity of the procedures and these showed a minor severity within each investigated study. A comparison of both studies showed slightly higher scores involving liver transplantation. In contradiction to the common classification of these procedures as a moderate severity grade the score sheets applied here indicates a minor severity grade within each investigated study. Also, limitations and possible improvements in the design of our score sheets for defined interventions are reconsidered.