Sugical Anatomy of Liver Simplified for General Surgeons

I feel that the only reason general surgeons fear from liver is because lack of understanding or poor understanding of its anatomy.

And complicated segmental anatomy given in general surgery text books without proper explanation.(though very important and every surgeon should read it before reading my post.)

First forget about segments. You will be doing segmentectomies very rarely.

Just remember following terminologies:

1.     Right lobe

a.     Right anterior sector

b.     Right posterior sector

2.     Left lobe.

a.     Left Letral segment

b.     Segment 4

3.  Caudate lobe

Vascular structures that you can dissect extrahepatically in porta. (Dissect slowly and carefully you just need to denude porta and you can do each type of liver surgery)

Ø  Hepatic artery proper (hepatic artery after gastroduodenal artery before that it is called common hepatic artery)

o   Right hepatic artery (mostly branch from hepatic artery proper or lie posterior to the bile duct when arises from SMA)

§  Right anterior sector artery

§  Right posterior sector artery

o   Left hepatic artery

§  Segment 4 artery (some time it arises from right)

Ø  Bile Duct:

o   CBD

o   Right hepatic duct

o   Left hepatic duct

                                

Technically You can see these structures in the porta outside liver but my plan in liver resections generally is quite simple dissect all the vascular structures and rest is bile ducts. Cut it in the end after parenchymal transection.

Ø  Hepatic veins: (at the top when you dissect falciform ligament)

·      Right hepatic vein

·      Middle left vein together

Inititally dissect falciform ligament until you can see right and left-middle vein insert in to IVC and dissect groove between right and middle- left.

·      Inferior hepatic veins: draining directly from right lobe to IVC on right side and caudate vein found on left side.

Now Few Simplified Anatomical Definitions of Liver lobes according to venous drainage

Right lobe: Liver tissue right to middle hepatic veini

Left lobe : Liver tissue left to middle hepatic vein.

Most people say middle hepatic vein is a part of left lobe but for me as a surgeon for better understanding I take middle hepatic vein as no man’s land. Like Indo China border dispute and I act as U.N. so I give land according to the need.

If middle hepatic vein is involved with tumor or tumor is very close my right hepatectomy will include middle hepatic vein also or in case of transplantation when graft volume is border line or CT shows right anterior sector is draining mostly in to middle vein.I will take middle hepatic with the right lobe.

If tumor is far away from middle hepatic I will keep middle hepatic vein with the left side. Or in case of transplantation when right vein is dominantly draining anterior or graft volume is adequate I will keep middle vein with the left lobe.

Same goes with left hepatectomy in transplantation when you are taking left lobe middle hepatic vein almost always remains with the left lobe.

Right anterior sector: area between middle hepatic and right hepatic vein.

Right posterior sector: area Right to right hepatic vein including right hepatic vein area.

Left lateral sector liver tissue left to falciform ligament

Segment 4 area between facifom ligament and middle hepatic vein.

Caudate lobe is a seprate entity.

With these facts in the next part I will try to right simplified techniques of different hepatectomies.