The session “Pre-operative embolization” covers two main areas in which embolotherapy plays a crucial role prior to surgery. There will be two lectures on each topic. The first two lectures will concern portal and hepatic vein embolization on the tumour-bearing liver to promote hypertrophy of the unaffected lope prior to curative partial hepatectomy. The third lecture will cover pre-operative embolisation of bone tumours in general, and the last lecture will focus on metastases from renal cell carcinoma specifically.
Portal and liver vein embolisation
Extended hepatectomy with curative intent is a commonly used treatment option for patients with various primary and secondary liver diseases. Advancements in surgical techniques and peri-operative management have allowed for more aggressive resection and broadened the spectrum of patients who are eligible for curative resection. However, the size of the future liver remnant remains a crucial factor in determining treatment eligibility and postoperative prognosis. Pre-operative portal vein embolisation is accepted as standard of care for patients undergoing partial hepatectomy to promote contralateral hepatic lobar hypertrophy. However, the potential insufficient growth as well as tumour progression in the time between embolization and surgery has led to the investigation of supplementary and alternative techniques. Hepatic vein embolization is a relatively new supplementary technique to portal vein embolization that has shown promising results concerning faster and more significant hypertrophy than portal vein embolization alone. The combination of portal and hepatic vein embolization is also known as hepatic venous deprivation.
Through the two first lectures of this section, you will become aware of the existing evidence regarding liver vein embolization in combination with portal vein embolization and learn about techniques and materials in both procedures. Furthermore, critical anatomical and pathophysiological considerations will be addressed.
Bone tumours and metastases
Oncological management continues to improve, consequently increasing the life expectancy for patients with advanced cancer. As patients continue to live longer with advanced cancer, the number of symptomatic metastases increase and surgical removal or reduction can be an option. However, surgery on bone metastases is associated with extensive intraoperative blood loss, as is surgery for a number of both benign and malignant primary bone tumours. Hence, several measures are commonly implemented to minimise intraoperative blood loss, including pre-operative embolization, which aims to reduce vascularity prior to surgery.
One of the earliest descriptions of therapeutic embolization is by Dawbarn. Already in 1904, JAMA published the description of injection of paraffin and Vaseline into tumour arteries to exclude the blood supply prior to extirpation. However, the development of the great variety of embolization procedures used today began in the 1960’s and 1970’s, as interventional radiology emerged as a discipline on the basis of the Seldinger technique from 1953. Nowadays, there is a vast selection of both permanent and temporary embolization materials available and several of them are utilised in pre-operative embolization of bone tumours and metastases.
The evidence on the effectiveness of pre-operative embolization of bone tumours and metastases is mainly based on a multitude of retrospective studies that use varying techniques and have come to conflicting conclusions. Through the two last lectures of our session, you will learn about the existing evidence regarding indications and optimal technique, illustrated with cases. There will also be time for a brush-up on the relevant anatomy and pathophysiology. Lastly, another focus will be on the potential risks of complications and how best to avoid them. The complications specific to pre-operative embolization are obviously non-target embolization, and the most severe ones are medullary injuries due to non-target embolization to the dominant anterior spinal contributor, also called artery of Adamkiewicz.