{
  "abstract": "Introduction Thermal ablation is a well-established modality for the treatment of hepatic tumours and is typically performed under general anaesthesia (GA). However, post-procedural pain control remains suboptimal and can contribute to prolonged hospital stays and increased opioid use. In this retrospective, single-centre cohort study, we evaluate the impact of incorporating hepatic hilar nerve block into the analgesic regimen for percutaneous, image-guided thermal ablation of liver tumours in a large tertiary centre in East London. Specifically, we assess the effect on intra-procedural sedation requirements and post-procedural analgesia.Methods We conducted a retrospective cohort study of patients who underwent percutaneous thermal ablation of hepatic tumours between April 2022 and April 2025 at a single centre. Data was extracted from electronic patient records and included visual analogue pain scores, intra-procedural analgesia and sedation requirements, patient co-morbidities, length of hospital stay, and procedure-related complications. Patients were categorised based on whether a hilar nerve block was administered prior to ablation.Results A total of 126 patients underwent liver tumour ablation with a hilar nerve block in addition to procedural sedation, while 115 patients received GA. Baseline demographics and tumour characteristics were comparable between groups, including mean tumour size (15.8 mm vs. 14.8 mm), tumour type distribution, and mean ablation time (9.8 vs. 10.3 minutes).Patients who had hilar nerve block demonstrated significantly lower intra-procedural analgesia and sedation requirements. There was a 36% (p=0.004) reduction in the average fentanyl dosage used in hilar nerve block group, and 29.2% (p=0.0016) reduction in the mean midazolam dosage . Pain control post-procedurally was improved in the nerve block group, with a mean maximum visual analogue pain score of 2.4 versus 5.5 in the control group .No complications were observed in the hilar nerve block group. One complication occurred in the control group involving post-procedural desaturation in a patient who received general anaesthesia. Additionally, no patients in the nerve block cohort required overnight inpatient admission, compared to 15 patients admitted for pain control and post-procedural complications. Results are demonstrated in table 1.Abstract P55 Table 1Baseline Characteristics, Procedural Parameters, and Outcomes in Patients Undergoing Liver Tumour Thermal Ablation with and Without Hilar Nerve Block Nerve Block Group (126) Control Group (115) Mean Age 63.8 60.7 Sex (Male; Female) M: 85; F: 41 M: 77; F: 38 Primary Tumour Type Hepatocellular carcinomaColorectalUveal Melanoma 114120 10861 Mean maximal tumour dimension (Range) 15.8mm (13 – 20mm) 14.8mm (9 – 23mm) Mean minimum distance to capsule 2mm 3mm Mean distance from Glisson’s sheath 31mm 38mm Mean Ablation Time 9.8 minutes 10.3 minutes Mean Total Fentanyl Dose 134 ug 210 ug Mean Total Midazolam Dose 1.7mg 2.4mg Mean maximum visual analogue score 2.4 5.5 Complications 0 1 No. Patients requiring inpatient stay overnight 0 15 Discussion Hilar nerve block during liver thermal ablation offers advantages in procedural pain control, reduces reliance on opioids and sedatives, and minimises the need for post-procedural hospital admission. With no complications observed in the nerve block cohort, this technique demonstrates both safety and clinical value. Its adoption has the potential to enhance patient experience, accelerate recovery, and optimise resource utilisation in hepatic oncology care.",
  "authors": [
    {
      "affiliations": [
        "The Royal London Hospital, UK"
      ],
      "name": "Sara Elsaadany"
    },
    {
      "affiliations": [
        "The Royal London Hospital, UK"
      ],
      "name": "Pallabhi Mandal"
    }
  ],
  "title": "P55 Hilar nerve block for liver thermal ablation: advancing regional anaesthesia in hepatic oncology",
  "uid": "8292952e-c22a-5b73-80d2-d5d198a9f7b1"
}