A retrospective, single-centre study has found that women more frequently experienced moderate to severe pain and required more analgesics for pain management when compared to men following percutaneous thermal liver ablation.
“The reasons why women and men experience different levels of pain are still an ongoing research topic,” write the study’s authors—led by Christiaan van der Leij (Maastricht University Medical Center, Maastricht, The Netherlands). Speaking to Interventional News, Robrecht Knapen (Maastricht University Medical Center, Maastricht, The Netherlands) stated that “sex hormones, genotype, and endogenous opioid function may all play a potential role in these differences in pain experiences,” however these variables have not been sufficiently borne out in clinical research to date.
Percutaneous radiofrequency (RFA) and microwave frequency (MWA) thermal liver ablation are minimally invasive treatment options for patients with hepatocellular carcinoma (HCC) or colorectal liver metastases (CRLM). The authors describe that, according to the Barcelona Clinic Liver Cancer (BCLC) prognosis and treatment strategy, very early stage and some early stage HCCs should be initially treated with thermal ablation. In patients with CRLM, liver surgery “remains the standard treatment”, van der Leij et al state, “however thermal ablation has been increasingly used over the last few years with low complication rates. With studies, like the COLLISION trial, indications for thermal liver ablation will likely increase in the future.”
Informing their present research, van der Leij et al note that approximately 10% of patients treated with thermal ablation develop moderate to severe acute post-procedural pain. “This rate is 30–80% following surgery,” the authors add. Despite treatment modality, ineffective post-procedural pain management can lead to “increased length of hospital stay, opioid use, delirium in elderly patients, and thromboembolic complications,” they describe. Ablative factors which predict pain following treatment have been speculated, such as ablation volume, increase aspartate aminotransferase levels, and tumour location, which van der Leij and colleagues aimed to better define.
Their retrospective, single-centre cohort study was carried out at Maastricht University Medical Center, in Maastricht, The Netherlands. A total of 183 patients were included and treated with percutaneous thermal liver ablation for primary or secondary liver tumours between January 2018 and May 2022. Patients included were ≥18 years and had a thermal liver ablation performed with computed tomography (CT) or ultrasound guidance.
All patients received imaging prior to treatment and were routinely checked by the anaesthesiologist. The authors explain that typically, thermal ablation is performed under procedural sedation (PSA) using propofol and an opioid, or, if the patient does not meet the criteria for this due to high body mass index (BMI), sleep apnoea, or a prior unsuccessful PSA, general anaesthesia is given. Regardless of anaesthesia technique, all patients received lidocaine or bupivacaine as supplementary locoregional anaesthesia before the ablation procedure, van der Leij et al state.
Clinical outcomes were the maximal numeric ranking scale (NRS) score, ranging from 0 (no pain) to 10 (maximal pain), at the recovery after ablation, the prevalence of moderate/severe post-procedural pain (defined as NRS score ≥4) at the recovery room, and the NRS score at arrival recovery.
Of the 183 patients included—of whom 67% were men—at baseline, men were older on average, had a higher BMI, suffered from more primary liver tumours, and had larger mean maximal lesion diameters. At recovery, women exhibited a higher average maximal pain intensity (3.88 vs. 2.73) and a higher prevalence of post-ablation pain (NRS 4–10) compared to men. Regression analyses with adjustments for baseline differences showed that women suffered more from post-procedural pain (59% vs. 35%; adjusted odds ratio [aOR]: 2.50, 95% confidence interval [CI]: 1.16–5.39), and needed analgesics more often at recovery (77% vs. 63%; aOR: 2.43, 95% CI: 1.07–5.48) compared to men.
No differences were seen in the length of stay at the recovery, duration of anaesthesia, procedure time, and complication rate. Location of the tumour (subcapsular or deep), total tumours per patient, and distinction between primary and secondary tumours had no influence on the NRS, write van der Leij et al.
The authors draw attention to several limitations of their study, firstly its single-centre design and retrospectively collected data with a subjective pain measurement. They note that anaesthesiologists were free to choose analgesics during the ablation procedure, which may have caused “inconsistent sedation levels”. However, comparable medications, dosage, and sedation technique were used in both groups, minimising this bias, the authors state.
van der Leij and colleagues state that, until patient and procedural factors which influence pain have been “thoroughly investigated, anaesthesia care providers need to consider post-procedural pain differences in women undergoing thermal liver ablation”. Concluding, they state that higher dosages of analgesics should be considered—possibly morphine acting opioids—to reduce post-procedural excessive pain.
