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

Abstract

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.

Keywords: Abdominal pain; chemical neurolysis; chronic pain; intractable pain; neoplasms; neurolysis; opioid; quality of life; splanchnic nerve block; sympathetic.

Figure 1

Revised Cochrane risk-of-bias tool for randomised trials (RoB 2)

Figure 2

Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram

Figure 3

Forest plot for pain outcome: (a) post-procedure pain scores at 1 week; (b) post-procedure pain scores at 2 weeks; (c) post-procedure pain scores at 4 weeks; (d) post-procedure pain scores at 8 weeks; (e) post-procedure pain at 12 weeks; (f) post-procedure pain at 24 weeks. CI = Confidence interval; SD = Standard deviation; SNN,=splanchnic nerve neurolysis

Figure 4

Forest plot for daily narcotics consumption outcome: (a) daily narcotics consumption at 2 weeks; (b) daily narcotics consumption at 4 weeks; (c) daily narcotics consumption at 12 weeks, (d) daily narcotics consumption at 24 weeks. CI = Confidence interval; SD = Standard deviation; SNN = splanchnic nerve neurolysis

Figure 5

Forest plot for Quality of Life (QOL) assessment outcome- (a) QOL (scale: 0–10) at 4 weeks; (b) QOL (scale: 0–10) at 8 weeks; (c) QOL (short form health survey SF-36) Physical function at 4 weeks; (d) QOL (short form health survey SF-36) Physical function at 12 weeks; (e) QOL (SF-36) Mental function at 4 weeks; (f) QOL (SF-36) Mental function at 12 weeks. CI = Confidence interval; SD = Standard deviation; SNN = splanchnic nerve neurolysis; 1M = 1 month; 3M = 3 month

Figure 6

Sub-group analysis based on study design (RCTs vs non-RCTs). RCT = randomised controlled trial

Figure 7

Sensitivity analysis at 1, 8, 12, and 24 weeks

Figure 8

Evidence quality analysis using GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) Pro GDT (Guideline Development Tool)