Yes, a partial liver removal is possible, called a liver resection or partial hepatectomy. The liver is a unique organ with a remarkable ability to regrow, which makes this type of surgery feasible. This organ acts as the body’s central processing plant, performing hundreds of functions, most notably the detoxification of blood and the metabolism of carbohydrates, fats, and proteins. A liver resection involves removing a diseased or damaged section while preserving enough healthy tissue for the body to maintain normal function. The remaining portion of the organ then grows back to nearly its original size within a few months.
The Biological Basis for Regeneration
The liver is the only solid organ in the human body capable of restoring its mass following a substantial loss of tissue. This regenerative capacity is not a true regeneration where the original shape is perfectly replicated, but rather a process of compensatory growth called hypertrophy and hyperplasia. The cells that make up the liver, called hepatocytes, are typically quiescent, meaning they are in a resting state and not actively dividing.
Following a partial hepatectomy, the remaining liver tissue begins a rapid process of cell division. This response is triggered by a cascade of signaling molecules, including growth factors that circulate in the bloodstream. Key among these are factors like hepatocyte growth factor (HGF) and various interleukins, which bind to receptors on the remaining hepatocytes.
This binding stimulates the resting hepatocytes to re-enter the cell cycle and proliferate. The primary goal of this growth is to restore the organ’s overall functional mass, ensuring it can handle the body’s metabolic demands, which typically occurs within a few weeks to months after the operation.
Clinical Indications for Partial Removal
Partial liver removal is performed to address specific medical conditions. The most frequent need for this surgery is the presence of cancerous growths, either tumors that began in the liver or those that have spread from other organs. Primary liver cancers, such as hepatocellular carcinoma, are often treated with a resection.
Metastatic cancers, most commonly those originating from the colon or rectum, frequently spread to the liver and are a major indication for partial hepatectomy. Removing these secondary tumors offers the best chance for long-term survival. Beyond malignant disease, the procedure is also used to treat large benign growths, such as certain adenomas or focal nodular hyperplasia, which can cause symptoms or carry a risk of rupture or malignancy.
Trauma to the abdomen resulting in severe liver injury may also require a resection to remove irreparably damaged tissue and control bleeding. A unique clinical indication for partial hepatectomy is living donor liver transplantation, where a healthy individual donates a portion of their liver to a recipient. The donated segment is transplanted into the patient, and the donor’s remaining liver regrows.
Determining the Safe Limit for Resection
The primary factor in planning a liver resection is ensuring that the remaining liver volume (RLV) will be sufficient to support the patient’s bodily functions immediately after the surgery. Surgeons use imaging techniques like computed tomography (CT) and magnetic resonance imaging (MRI) to precisely calculate this remaining volume before the operation. The liver is anatomically divided into eight functional segments, known as the Couinaud classification, which helps surgeons plan the removal along clearly defined planes.
The amount of liver that can be safely removed depends heavily on the underlying health of the patient’s liver. For a patient with a completely healthy liver, up to 75% of the organ’s total volume can often be safely resected. However, if the patient has underlying liver disease, such as cirrhosis or significant steatosis (fatty liver), the functional reserve is lower, and the safe limit for removal decreases.
In cases of chronic liver disease, surgeons typically aim to leave at least 30% to 40% of the original liver volume to prevent post-operative liver failure. Calculating the RLV is a complex process that takes into account the volume, quality, and blood supply of the tissue that will remain.