Background: Superior hypogastric plexus neurolytic (SHP-N) block is the mainstay management for pelvic cancer pain of visceral origin when oral opioids fail due to inefficacy or intolerance to side effects. Unfortunately, SHP-N has the potential to control pelvic pain in 62%-72% of patients at best, because chronic pelvic pain may assume additional characteristics other than visceral.
Objective: Combining SHP-N with pulsed radiofrequency (PRF) of the sacral roots might block most of the pain characteristics emanating from the pelvic structures and improve the success rate of SHP-N in controlling pelvic and perineal cancer pain.
Study design: This study was a prospective randomized controlled clinical trial.
Settings: The research took place in the interventional pain unit of a tertiary center in the university hospital.
Methods: Fifty-eight patients complaining of cancer-related chronic pelvic and perineal pain were randomized to either the PRF + SHP group (n = 29), which received SHP-N combined with PRF of the sacral roots S2-4, or the SHP group (n = 29), which received SHP-N alone. The outcome variables were the percentage of patients who showed a > 50% reduction in their Visual Analog Scale (VAS) pain score, the VAS pain score, and global perceived effect evaluated during a 3-month follow-up period.
Results: The percentage of patients who showed a > 50% reduction in their VAS pain score was significantly higher in the SHP + PRF group compared to the SHP group when assessed at one month (92.9% [n = 26] vs 57.7% [n = 15]; P = .003) and 3 months (85.7% [n = 24) vs 53.8% [n = 14]; P = .01) post procedure, respectively. However, no significant difference was observed between the 2 groups at the 6-month evaluation (SHP + PRF [57.1% (n = 16)] vs SHP [50% (n = 13)]; P = .59). There was a statistically significant reduction of VAS in the SHP + PRF group in comparison to the SHP group at one month (2.8 ± 0.9 vs 3.5 ± 1.2 [mean difference, -0.7 (95% confidence interval [CI], -1.29 to -0.1), P = .01]), 2 months (2.8 ± 0.9 vs 3.5 ± 1.2 [mean difference, -0.64 (95% CI, -1.23 to -0.05), P = .03]), and 3 months (2.7 ± 1 vs 3.4 ± 1.2 [mean difference, -0.67 (95% CI, -1.29 to -0.05)], P = .03]) post procedure, respectively; however, the 2 groups did not significantly differ at 2 weeks, 4, 5, and 6 months post procedure. Regarding postprocedural analgesic consumption, there were trends towards reduced opioid consumption at all postprocedural measured time points in the SHP+PRF group compared to the SHP group; these differences reached statistical significance at 2 months (median, 30 [interquartile range (IQR), 0.00-30] vs median, 45 [IQR, 30-90]; P = .046) and 3 months (median, 0.00 [IQR, 0.00-30] vs median, 30 [IQR, 0.00-67.5]; P = .016) post procedure, respectively.
Limitations: The study follow-up period is limited to 6 months only.
Conclusions: SHP-N combined with PRF of the sacral roots (S2, 3, 4) provided a better analgesic effect than SHP-N alone for patients with chronic pelvic and perineal pain related to pelvic cancer.
Trial registry: ClinicalTrials.gov. NCT03228316.
Key words: Pelvic pain, pulsed radiofrequency, sacral roots, superior hypogastric plexus.