Hepatic Hilar Nerve Block Versus Sham in Pain Control During Liver Ablation and TACE Procedures

Prospective Randomized Double-Blind Study of Pain Control With Hepatic Hilum Nerve Block Versus Sham Procedure For Hepatic Chemoembolization or Radiofrequency Ablation

This study is aimed at assessing the effectiveness of a novel liver specific nerve block in improving pain control during painful liver interventional radiology procedures including liver tumoral ablation and trans arterial chemoembolization, two procedures aimed at controlling liver tumors, but that can be associated with significant pain. This novel hepatic specific nerve block was designed by us and initial retrospective results suggests it might help in controlling such liver procedural derived pain. The study was designed to compare the liver block to a sham procedure in a blinded context and to follow the participants over three days post-procedure to asses for pain levels.

This is a prospective study. Experienced interventional radiologists in the two McGill University Health Centre study centers (Royal Victoria Hospital and Montreal General Hospital) will perform all procedures:

• 80 consecutive subjects meeting the eligibility criteria, scheduled for chemoembolization of the liver for primary or secondary liver malignancies OR radiofrequency ablation of the liver for primary or secondary liver malignancies.
• Consent will be obtained from all patients by an interventional radiologist.
• All procedures will be performed by a qualified interventional radiology medical doctor (IRMD).
• Patients who accept to participate and fit the criteria will be randomized to either receive hepatic plexus block or a placebo control procedure, consisting of injection of normal saline.
• Hepatic hilum plexus nerve block will consist of the ultrasound-guided injection of ropivacaine at the hepatic hilum anterior to the portal vein as close to the bifurcation as possible. In the sham control group, the same location will be targeted, but only normal saline will be injected.
• A member of the radiology technologists will load the syringe with either ropivacaine or normal saline and the IRMD will thus be blinded to the patient's allocated group.
• All patients will be offered IV analgesia using midazolam and fentanyl during the procedure at set regular intervals as per our standard regimen.
• Similar IV analgesics as well as oral analgesics will be provided as per set orders during the recovery period in the post-procedural recovery room (PACU)
• The patient will be discharged home with standard prescriptions for home analgesics which include routine medication and medication to be used for breakthrough pain. While at home they will be entering pain surveys three times per day for three days.
• Data will be gathered, stored, and analyzed. The analysis will be stratified into patients who have received chemoembolization and patients who have received radiofrequency ablation.
• Follow-up of the patient will occur as per routine 4-6 weeks post chemoembolization/radiofrequency ablation to assess the clinical success of the therapeutic procedure (ablation and TACE) and patient satisfaction with pain control.

Subject data collection on the day of the procedure will include demographics, relevant medical history, vital signs before and during the procedure, use of IV analgesics, use of oral analgesics, use of nerve block or sham procedure and visual analogue pain scales at set intervals during hospital stay. Subject data collection while at home will include visual analogue pain scale and self-recording of medication intake.

Inclusion Criteria:

1. Patients referred to the Interventional Radiology department and approved for a chemo-embolization or radiofrequency ablation of malignant primary or secondary liver tumour.
2. At least 18 y.o.

Exclusion Criteria:

1. Patients in whom the vascular anatomy prevents safe access to the hepatic hilum or patients in whom general anaesthesia was performed.
2. Patients who have known allergy to any anaesthetic agent in the regular protocol (fentanyl, midazolam, ropivacaine).
3. Patients with signs of skin infection at the entry site of the needle used to perform the nerve block
4. Patients with signs of infection such as fever or acute increase in wight blood cell count.
5. Patients with uncorrectable abnormal coagulation status (INR >1.5 and platelets < 50000 without use of anticoagulation agents).
6. Patients with pre-existing conditions, which, in the opinion of the investigator, interfere with the conduct of the study (these reasons will be recorded)
7. Patients, who are uncooperative, cannot follow instructions, or who are unlikely to comply with follow-up appointments or fill-out the post-procedural pain questionnaires.
8. Patients with a mental state that may preclude completion of the study procedure or are unable to provide informed consent.