Efficacy of splanchnic nerve neurolysis in the management of upper abdominal cancer pain: A systematic review and meta-analysis.

Background and Aims: Neurolytic splanchnic nerve block (NSNB) is practised in intractable abdominal pain secondary to intra-abdominal malignancies. This review evaluated the efficacy of NSNB. Methods: PubMed, Embase, Scopus, and Cochrane databases were searched for articles published from January 2001 to October 2023. Two independent reviewers extracted the data from the included studies. The quality of randomised controlled trials (RCTs) was assessed using the revised Cochrane risk-of-bias tool (RoB 2), and the Newcastle–Ottawa scale was used for cohort studies. Results: Fourteen articles (4 RCTs, 3 non-randomised prospective, and 7 retrospectives) were included. Ten articles were quantitatively assessed and demonstrated significant pain relief at 1 week (standardised mean difference (SMD): 3.46 [2.09, 4.83], P < 0.001, I2 = 95%), 2 weeks (SMD: 4.45 [2.61, 6.29], P < 0.001, I2 = 95%), 4 weeks (SMD: 3.35 [2.23, 4.47], P < 0.001, I2 = 97%), 8 weeks (SMD: 3.7 [2.71, 4.7], P < 0.001, I2 = 86%), 12 weeks (SMD: 4.01 [2.66, 5.36], P < 0.001, I2 = 95%), and 24 weeks (SMD: 2.54 [1.71,3.37], P < 0.001, I2 = 84%). Daily narcotic consumption and quality of life (QOL) significantly improved post neurolysis, but survival rates showed controversial results. Significant heterogeneity was reported, and sub-group analysis revealed a moderate level of variability [I2 = 47.3%] pertaining to study design as a source of heterogeneity. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Pro GDT recommendation for the primary objective was 'high' for the analysis of RCTs and 'very low' evidence quality for observational studies. Only transient minor complications were reported. Conclusion: NSNB appears to be an efficacious technique that provides substantial pain relief, reduces opioid consumption, and ameliorates QOL. [ABSTRACT FROM AUTHOR]