Can You Live With a Partial Liver?

People live full lives after a large part of their liver is removed, whether to take out a tumor or to donate a piece to someone else. The liver can regrow lost tissue far better than any other internal organ: what remains enlarges and takes over the work. What comes back is working capacity rather than the original organ, a bigger version of what was left, not a replica of what was removed.¹

How Quickly the Liver Grows Back

Function returns first. Right after a major operation, the liver’s working capacity can drop to about a third of what it was before.² Within 10 days, function typically climbs back to roughly three quarters of the original level.³ Size follows a similar pattern: in donors who gave the larger right side, the remaining liver grew by close to 90% within 10 days.⁴

At home during those weeks, fatigue is common, because rebuilding tissue uses a lot of energy. Appetite often returns gradually, and tiredness tends to ease in steps, with good and bad days mixed together.

Follow-up blood tests track how function is returning. In the first days they measure how well the liver is working, such as clotting and bilirubin, and those numbers usually start improving before your energy does. So you can have reassuring results and still feel worn out. Feeling better also does not mean the liver has finished adjusting, so scheduled tests continue.

Size keeps growing, more slowly, for months to years. Growth is fastest in the first 3 months, then slows.⁵ Donors who kept about 42% of their liver reached about 64% of their original volume at 1 month, 81% at 1 year and 88% at 4 years.⁶ Donors who kept about 63% were at 76% by 1 month and 91% by 4 years.⁷ The liver did not fully return to its original volume even 4 years later.⁸

A slightly smaller liver is normal and still enough for full function. The liver has more capacity than daily life demands, and regrowth stops once the body’s needs are met, not at the exact old size. People at 80 to 90% of their original volume generally have normal liver function.

How Much Liver Can Be Removed Safely

Surgeons plan around the future liver remnant, the share of liver that will be left after surgery. It is measured on a scan before the operation: a CT or MRI maps the liver in slices, and the radiology team outlines the whole liver and the tumor. Software adds up the volume of the part planned to be kept, and the surgeon uses the scan to decide where the cut will go. That volume is then expressed as a percentage of the total liver, and sometimes compared with body size, because a larger person needs more working liver.

In a healthy liver, the safe limit is commonly put at 20 to 30% left behind.⁹ One large surgical center uses 30% as its minimum for normal livers.¹⁰ If the liver is damaged, the same center wants at least 40% and preferably 50% left.¹¹

The threshold rises because fatty liver, scarring, previous chemotherapy and major prior injury can all hold back normal regrowth.¹² The most serious danger is liver failure after surgery when too little working liver remains.

Some questions are worth asking before a resection:

What percentage of my liver is planned to remain? That single number shapes much of your risk.
Do you consider my liver healthy or damaged, and what is that based on, such as fat, scarring or earlier chemotherapy?
What happens if the part left behind turns out to be borderline? Options such as growing it first may exist.
Which blood tests will be watched after surgery, and what results would suggest the liver is struggling?

When Too Little Liver Would Remain

Doctors can grow the healthy side before surgery. Portal vein embolization blocks the main blood vessel feeding the part of the liver to be removed, so the rest grows in advance.¹³ The part to be kept grew by about 38% on average, ranging from about 20% to 69%.¹⁴ Some people first told surgery was impossible can become candidates,¹⁵ and it can mean fewer complications and shorter hospital stays after the operation.¹⁶ Many surgical departments use it as standard care before major liver removal.¹⁷

A radiologist guides a thin needle through the skin of the upper belly, using ultrasound and X-ray imaging to find the right branch of the vein. Through that needle, small particles or plugs are placed to block the branch that feeds the side to be removed. Most people go home within a day or so, though some have mild pain, nausea or fever for a short time.

Surgery isn’t done right away, because the healthy side needs weeks to grow. A repeat scan some weeks later measures the part to be kept and shows whether it has reached a safe size. If growth is enough, the operation is scheduled. If not, the team can discuss other approaches or whether surgery is still appropriate.

Risks and Complications After Liver Surgery

Bile leaking from the cut surface happens in roughly 7 to 14% of liver operations.¹⁸¹⁹ Longer operations and certain types of removal raise the chance.²⁰ Bile is made in the liver and carried away through small channels, and the cut surface can sometimes leak it into the belly. It may show up as yellow-green fluid in a surgical drain, or as belly pain, fever or a swollen abdomen after you have gone home. A drain placed during or after surgery often shows the problem early, which is part of why drains are used.

Most leaks are moderate and are handled with drainage rather than another major operation.²¹ Many close on their own once the bile is drained away, so the drain may simply be left in longer. If fluid collects away from the drain, a radiologist can place a new tube through the skin using imaging. Sometimes a small stent is placed through the bile ducts by endoscopy to lower the pressure and let the leak heal. A repeat operation is reserved for the less common serious cases.

Small-for-size syndrome is when a piece of liver is too small to meet the body’s demands, mostly seen in transplants of partial livers.²² Too much blood rushing into it while it drains poorly can congest and damage it.²³ The injured piece may then make too little bile and clotting protein. A graft weighing less than 0.8% of the recipient’s body weight or with more than 30% fat raises the risk.²⁴ In ordinary resections, the equivalent worry is liver failure from too little remaining liver.

Clotting test results such as the INR rise after liver removal, because the liver makes clotting proteins.²⁵ An abnormal clotting result in the days after surgery is therefore expected, and usually not a reason for alarm alone.

After discharge, report fever or chills, worsening belly pain or swelling, yellowing of the skin or eyes, and fluid or bile-colored drainage from the wound.

Life After Donating Part of Your Liver

Death around donation surgery is extremely rare, and donors’ long-term survival matches that of similar non-donors.²⁶ Advanced liver disease caused by donation has not been reported.²⁷ Donors may have lasting slightly low platelet counts on blood tests.²⁸ Donors have also been found to have a higher risk of suicide and some cancers.²⁹

Major complications occur in 2 to 8% of donors.³⁰ Nearly 80% return to work within 3 months, and physical quality of life usually returns to normal in 6 to 12 months.³¹ But up to 20% develop a hernia at the incision, and 27% have chronic pain after the first year.³² A quarter report ongoing limits on activity, and 22 to 40% still face financial strain two years later.³³ Most donors do not regret donating, though about 8% have depression or anxiety.³⁴

Time off work can last weeks to months, and the pay lost is one of the main sources of strain. Ask the transplant team’s social worker or financial coordinator what costs are covered, such as evaluation and surgery, and what is not, such as lost wages and travel. Check your employer’s leave and disability policies before the date is set, since paid leave varies widely.

Ask whether your center offers a smaller-incision approach, such as laparoscopic or robotic surgery, and whether you are a good candidate. Smaller incisions can mean less scarring, though the choice depends on the center’s experience and the type of liver piece being taken. Ask also how the incision will be closed and what the team does to lower the risk of a hernia.

For the first weeks you won’t be able to lift, drive or manage a household as usual, so line up someone who can stay or visit regularly. Arrange help with meals, shopping, children or pets, and rides to follow-up visits. Ask the team, too, about mental health support before and after donation.

What Helps or Slows Regrowth

Ageing reduces how fast the liver regrows but not its ability to reach its full size.³⁵ In split-liver transplants, young recipients regrew grafts more than older ones.³⁶ Older livers, and those with chronic disease, may regrow less well.³⁷

Branched-chain amino acids, protein building blocks found in meat, dairy and supplements, may support liver regrowth.³⁸ After liver removal, taking these supplements twice daily for six months improved liver function and regrowth.³⁹ Ask your team before taking supplements, as advice depends on your case.

Everyday habits matter too. Eat regular meals with enough protein and energy, and keep follow-up appointments for blood tests. Alcohol is processed by the liver, so avoiding it while the liver is rebuilding takes a load off the organ. Ask your team how long to avoid it, since that depends on your surgery and the health of your liver.

Check every medicine and supplement with your team. Some painkillers, herbal products and supplements can strain the liver, even over-the-counter ones. Acetaminophen (paracetamol) is a common example: it is often used, but the safe dose is a question for your team after liver surgery. Many common drugs are processed normally even soon after major removal, though doctors may adjust some doses based on blood tests. Don’t change doses on your own.

Why the Liver Can Regrow at All

After surgery, more blood is forced through the smaller liver, and that extra pressure helps switch on regrowth.⁴⁰ The liver gets most of its blood from the gut, and all of it has to pass through whatever liver is left. That same effect is why blocking one side’s vein ahead of surgery makes the other side grow.

Many chemical signals then drive liver cells to divide, in phases that start, continue and then stop.⁴¹ Cells that are normally resting are switched into dividing. Signals keep the division going while the body still needs more liver, and then other signals bring it to a stop, which is why the liver does not grow without limit.

The removed lobe does not reappear. Existing cells multiply and the remaining tissue enlarges, so the shape changes.⁴²