Non-Anatomical Liver Resection

Non-anatomical liver resection — also referred to as atypical, wedge, or parenchyma-preserving resection — involves the removal of a liver tumour or lesion with a surrounding margin of healthy tissue, without adhering to the boundaries of Couinaud's anatomical liver segments or sections. In contrast to formal anatomical resections (segmentectomy, sectionectomy, hemihepatectomy) that excise defined hepatic segments guided by their portal pedicles, non-anatomical resection follows the shortest tumour-free margin around the lesion, maximising preservation of functional liver parenchyma. This approach is particularly valuable in patients with reduced liver reserve — such as those with cirrhosis or those who have received extensive chemotherapy — where conserving liver volume is paramount.

Indications for non-anatomical liver resection include small peripheral hepatocellular carcinomas (HCC) in cirrhotic patients, colorectal liver metastases (particularly multiple or bilateral lesions requiring parenchyma-sparing strategies), symptomatic benign lesions (large haemangiomas, hepatic adenomas, hydatid cysts), and trauma. The oncological adequacy of non-anatomical resection for HCC has been debated; studies suggest similar long-term survival compared to anatomical resection when resection margins are negative (R0), though some evidence favours anatomical resection for tumours with portal vein microinvasion. For colorectal metastases, non-anatomical resection with adequate margins is widely accepted.

Non-anatomical resections are well suited to laparoscopic or robotic-assisted approaches given the generally peripheral location of suitable lesions. Intraoperative ultrasound is indispensable for real-time localisation of lesions, assessment of proximity to major vascular and biliary structures, and guidance of the resection line. Haemostasis is achieved through a combination of ultrasonic energy devices, bipolar coagulation, haemostatic mesh, and fibrin sealants. Blood loss is typically low, and recovery after laparoscopic non-anatomical resection is rapid, with hospital stays of 2–4 days at our centre. Our HPB surgeons tailor the surgical approach to each patient's tumour biology, liver function, and overall fitness.