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Proposal of a New Comprehensive Notation for Hepatectomy

The “New World” Terminology

Nagino, Masato MD; DeMatteo, Ronald MD; Lang, Hauke MD; Cherqui, Daniel MD§; Malago, Massimo MD; Kawakatsu, Shoji MD; DeOliveira, Michelle L. MD||; Adam, René MD§; Aldrighetti, Luca MD∗∗; Boudjema, Karim MD††; Chapman, William MD‡‡; Clary, Bryan MD§§; de Santibañes, Eduardo MD¶¶; Dong, Jiahong MD||||; Ebata, Tomoki MD∗∗∗; Endo, Itaru MD†††; Geller, David MD‡‡‡; Guglielmi, Alfredo MD§§§; Kato, Tomoaki MD¶¶¶; Lee, Sung-Gyu MD||||||; Lodge, Peter MD∗∗∗∗; Nadalin, Silvio MD††††; Pinna, Antonio MD‡‡‡‡; Polak, Wojciech MD§§§§; Soubrane, Olivier MD¶¶¶¶; Clavien, Pierre-Alain MD||

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doi: 10.1097/SLA.0000000000004808
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The Brisbane 2000 nomenclature of hepatic anatomy and resections was approved by the General Assembly of the International Hepato-Pancreato-Biliary Association at the fourth biennial meeting of the society in Brisbane, Australia in 2000.1 Thereafter, as this nomenclature system has been used increasingly widely,2 the confusion regarding the anatomical nomenclature of the liver has decreased gradually. However, the problem is that the Brisbane Nomenclature system proposed rather complicated terms for hepatectomy, and multiple terms for the same type of resection. For example, the terms “left medial sectionectomy,” “resection segment 4,” and “segmentectomy 4” were proposed for segment 4 resection.1 Similarly, the labels “right trisectionectomy,” “extended right hepatectomy,” and “extended right hemihepatectomy” were proposed for the removal of segments 4–8. The terms “segmentectomy,” “sectionectomy,” and “sectorectomy” are also difficult to understand for many surgeons and may cause confusion. Furthermore, the Brisbane Nomenclature system did not address cases of nonanatomical resections, multiple resections, and combined bilio-vascular resections. Accordingly, the type of hepatectomy is still somewhat described arbitrarily, causing much puzzlement and inconvenience.

To resolve this issue, we herein propose a new comprehensive notation for hepatectomy based on the concept of Couinaud hepatic segmental anatomy.3,4 Of note, Couinaud anatomy was also the basis of the Brisbane system, which mentioned in the footnote of Table 3 of the original article1: “It is also acceptable to refer to any resection by its third-order segments, for example, right hemihepatectomy can also be called resection Sg5-8.” Such notation fits any hepatobiliary surgeon, who understands Couinaud hepatic segmental anatomy, to describe their hepatectomies.5–8 Thus, we have to mention that the use of Couinaud concept itself may not be a novel aspect of our proposal.

The general rules of the new notation are as follows: (1) the type of hepatectomy is expressed as Couinaud hepatic segment(s) resected, following the letter “H” which stands for hepatectomy. For a nonanatomical resection,9,10 the segment number is used with an apostrophe (‘); (2) in the en bloc resection of multiple segments, the numbers of the hepatic segments resected are described in ascending order. However, the numbers of segments resected nonanatomically are recorded at the end; (3) separate resections of multiple segments are separated with a slash (/); (4) combined en bloc resection of the extrahepatic bile duct that includes the hilar bifurcation, portal vein, hepatic artery, right hepatic vein, middle hepatic vein, or inferior vena cava is expressed by adding “-B,” “-PV,” “-HA,” “-RHV,” “-MHV,” or “-IVC,” respectively, following the number(s) of hepatic segment(s) resected. Note that “-RHV” or “-MHV” is used when at least the first half of the vein starting from the inferior vena cava is removed; (5) combined pancreatoduodenectomy is expressed by adding “-PD.” Examples of the new notation for various types of hepatectomy are shown in Table 1 and Figures 1A–C. This notation seems simple, clear at a glance, easy to teach, and available for all types of hepatectomy, ranging from simple resection for metastatic liver cancer to complicated hepatobiliary resection for perihilar cholangiocarcinoma.

TABLE 1 - Examples of the New Notation for Hepatectomy
Type of Hepatectomy (Traditional Nomenclature) New Notation
1 Anatomical resection of S6 H6
2 Nonanatomical resection of S6 H6′
3 Anatomical resection of S5 and S6 H56
4 Nonanatomical en bloc resection of S5 and S6 H5′6′
5 Nonanatomical separate resection of S5 and S6 H5′/6′
6 Anatomical resection of S6 with partial extension to S5 and S7 H65′7′
7 Nonanatomical separate resection of S6 × 2 H6′/6′
8 Medial sectionectomy with partial extension to S5 H45′
9 Central bisectionectomy and 1 separate nonanatomical en bloc resection of S2 and S3 H458/2′3′
10 Left lateral sectionectomy and 3 separate nonanatomical resections of S5, S6, and S7 H23/5′/6′/7′
11 Anterior sectionectomy H58
12 Posterior sectionectomy H67
13 No. 12 procedure with partial extension to S8 and RHV resection H678′-RHV
14 Left hemihepatectomy H234
15 No. 14 procedure and 2 separate nonanatomical resections of S6 and S8 H234/6′/8′
16 Right hemihepatectomy H5678
17 No. 16 procedure and 2 separate nonanatomical resections of S2 and S4 H5678/2′/4′
18 Left trisectionectomy H23458
19 Right trisectionectomy H45678
20 Left hemihepatectomy with combined resection of the caudate lobe and extrahepatic bile duct H1234-B
21 No. 20 procedure with partial extension to S58 and MHV resection H12345′8′-B-MHV
22 Right hemihepatectomy with combined resection of the caudate lobe and extrahepatic bile duct H15678-B
23 No. 22 procedure with partial extension to S4 and MHV resection H156784′-B-MHV
24 No. 22 procedure with pancreatoduodenectomy H15678-B-PD
25 Left trisectionectomy with combined resection of the caudate lobe and extrahepatic bile duct H123458-B
26 No. 25 procedure with portal vein resection H123458-B-PV
27 No. 25 procedure with portal vein and hepatic artery resection H123458-B-PV-HA
28 Right trisectionectomy with combined resection of the caudate lobe and extrahepatic bile duct H145678-B
29 No. 28 procedure with portal vein resection H145678-B-PV
30 No. 28 procedure with inferior vena cava resection H145678-B-IVC
B indicates extrahepatic bile duct resection; H, hepatectomy; HA, hepatic artery resection; IVC, inferior vena cava resection; MHV, middle hepatic vein resection; PD, pancreatoduodenectomy; PV, portal vein resection; RHV, right hepatic vein resection; S, Couinaud hepatic segment.
See Figure 1A.
See Figure 1B.
See Figure 1C.

FIGURE 1
FIGURE 1:
Scheme and new notation for various types of hepatectomy. A, minor hepatectomy. B, left-sided major hepatectomy. C, right-sided major hepatectomy. Note that the portal vein and hepatic artery are omitted in Figures 1B and 1C. MHV indicates middle hepatic vein; RHV, right hepatic vein.

The authors discussed the following 3 issues. The first issue was whether to indicate if <50% or >50% of a segment was removed in a nonanatomical resection. The problem is that the estimation of <50% or >50% remains subjective, and unlikely to be based on volumetry. The second issue was whether the concept of a subsegment (eg, subsegment 4a, or subsegment 8c) should be included although the definitions of subsegment/segment are still debatable.10–13 Information of lymphadenectomy was also discussed, but the majority of the present authors opposed its inclusion because lymphadenectomy is not a standardized part of en bloc resection with the liver, thus this information, if necessary, should be separately described. Although these additional labels would be useful, our top priority for the notation is its simplicity. We were concerned that more information would increase its complexity and make it less widely used. Accordingly, a consensus of the present authors was that these 3 items should not be incorporated into the notation, although future revision may propose a different approach.

We also felt that an acronym may facilitate the diffusion and reporting of the new nomenclature. We, therefore, propose the acronym “New World” for a newway of reporting liver dissections. We hope that this “new world” nomenclature will be widely accepted and used routinely to prevent confusion and the use of multiple terms for the same type of hepatectomy. Clarity in oral communication may benefit from this new terminology; which notation should be used especially for operative reports, abstracts at meetings, and publications. In addition, we would wish that Journal editors would consider its use as a matter of policy.

REFERENCES

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Keywords:

hepatectomy, nomenclature, terminology

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