Effectiveness of splanchnic nerve neurolysis for targeting location of cancer pain: Using the pain drawing as an outcome variable

The effectiveness of splanchnic nerve neurolysis (SNN) for cancer-related abdominal pain has been investigated using numeric pain intensity rating as an outcome variable. The outcome variable in this study used the grid method for obtaining a targeted pain drawing score on 60 patients with pain from pancreatic or gastro-intestinal primary cancers or metastatic disease to the abdominal region. Results demonstrate excellent inter-rater agreement (intra-class correlation [ICC] coefficient at pre-SNN = 0.97 and ICC at within one month post-SNN = 0.98) for the grid method of scoring the pain drawing and demonstrate psychometric generalizability among patients with cancerrelated pain. Using the Wilcoxon signed rank test and associated effect sizes, results show significant improvement in dispersion of pain following SNN. Effect sizes for the difference in pre-SNN to 2 post-SNN time points were higher for the pain drawing than for pain intensity rating. Specifically, the effect size difference from pre- to within one month post-SNN was r = 0.42 for pain drawing versus r = 0.23 for pain intensity rating. Based on a smaller subset of patients who were seen within 1 – 6 months following SNN, the effect size difference from pre-SNN was r = 0.46 for pain drawing versus r = 0.00 for pain intensity rating. Collectively, these data support the use of the pain drawing as a reliable outcome measure among patients with cancer pain for procedures such as SNN that target specific location and dispersion of pain.