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ORIGINAL
Utility of virtual three-dimensional image analysis forlaparoscopic gastrectomy conducted by trainee surgeons
Masaaki Nishi, Kozo Yoshikawa, Jun Higashijima, Takuya Tokunaga, Chie Takasu, Hideya Kashihara,
Daichi Ishikawa, and Mitsuo Shimada
Department of Surgery, University of Tokushima Graduate School, Tokushima, Japan

Abstract : Purpose The aim of this study was to investigate the utility the three-dimensional (3D) imaging forlaparoscopic gastrectomy performed by trainee surgeons. Methods 3D-reconstruction was performed using
multi-detector computed tomography (MDCT) and SYNAPSE VINCENT software. Trainee surgeons made 3D-imaging and checked the anatomical structure. Thirty-three patients who underwent laparoscopic gastrectomy(LG) for gastric cancer were examined. Trainees performed 19 LG, while specialists performed 14 LG. The vascular pattern and the surgical outcomes were evaluated. Result 3D imaging depicted the correct positional relationship between the gastric vasculatures and the organs. Regarding vascular pattern detected by 3D imaging,the origins of the infrapyloric artery were the right gastroepiploic artery in 12 cases (36%), the gastroduodenalartery in eight cases (24%), the bifurcation of the right gastroepiploic artery and gastroduodenal artery in sevencases (21%), and not detected in one case (3%). The types of confluence of the infrapyloric vein were the right
gastroepiploic vein in 16 cases (48%), the anterior superior pancreatoduodenal vein in 10 cases (30%), and not detected in seven cases (21%). Surgical outcomes were not different between trainee group using intraoperative 3D
image with the specialist in instruction group without the intraoperative 3D image. Conclusions Preoperative 3D
imaging might contribute to successful and safe LG by trainee surgeons. J. Med. Invest. 66 : 280-284, August, 2019
Keywords : three-dimensional image, laparoscopic gastrectomy, trainee surgeons

INTRODUCTION
Laparoscopic surgery has dramatically improved over the
past two decades, and the indications for laparoscopic surgery
have been widened within the gastrointestinal surgery field.
Laparoscopic gastrectomy is becoming a standard procedure forearly gastric cancer in Japan and Korea. A nationwide survey
by the Japan Society of Endoscopic Surgery (JSES) reported
that 4,765 cases of laparoscopic gastrectomy were performed in
1 year in Japan (1). However, for trainee surgeons, laparoscopic
gastrectomy has several difficult components, including lymph
node dissection and resection of several blood vessels. Misunderstanding of the local anatomy can result in severe complications,such as pancreatic fistula and intraoperative bleeding.
To reduce surgical complications and plan accurate operations, patients should be evaluated using precise and comprehensive imaging techniques preoperatively for accurate delineationof the local anatomy. Recently, preoperative evaluation of thevasculature based on a three-dimensional (3D) imaging technique resulted in a significantly improved surgical outcome forpatients undergoing abdominal surgery (2-7). In gastrectomy,
only a few studies have investigated the utility of 3D imaging(4, 5), and there are no reports concerning about the utility of
3D imaging technique as an educational tool for gastrectomy
performed by trainee surgeons.
Therefore, the aim of this study was to investigate the utilityof the 3D imaging in laparoscopic gastrectomy performed bytrainee surgeons.
Received for publication October 29, 2018 ; accepted May 12, 2019.
Address correspondence and reprint requests to Masaaki Nishi, MD,
Department of Surgery, Institute of Health Biosciences, University ofTokushima Graduate School 3-18-15, Kuramoto-cho, Tokushima 7708503, Japan and Fax : +81-88-631-9698.

METHODS
Patients

Thirty-three patients (male, n = 22 ; male, n = 11 ; mean age,
66 years) who underwent laparoscopic gastrectomy for gastriccancer during the period between January 2013 and May 2014
in Tokushima University Hospital were examined in this study.
Trainees performed 19 laparoscopic gastrectomies, while specialists performed 14 laparoscopic gastrectomies. Trainees werebeginners in terms of laparoscopic gastrectomy and had 6-10
years of experience as surgeons after graduation from medical
school. Specialists were qualified surgeons according to theendoscopic surgical skill qualification system of the JapaneseSociety for Endoscopic Surgery.

Imaging technique
Multi detector computed tomography (MDCT) examinations
were performed using Aquilion 16 (Toshiba Medical Systems
Corporation, Tochigi, Japan) at the University of Tokushima. We
adopted a multiphase computed tomography (CT) protocol to acquire three image sets (arterial, portal, and equilibrium phases).
The scans for each phase were acquired at 15 seconds (arterial),
30 seconds (portal), and 180 seconds (equilibrium phase) after
the administration of the nonionic contrast material, iopamidol(Iopamiron 370 ; Nihon Schering, Osaka, Japan), at a rate of 3
mL/s. Data from the arterial and portal phases were utilized inthis study. Details of the imaging method were reported previously (7).

Processing of gastric vessel data
Three-dimensional (3D) -reconstruction of the gastric vasculature was performed using data from contrast enhanced MDCTand SYNAPSE VINCENT software (FUJIFILM MEDICAL
CO.LTD., TOKYO JAPAN) (7). Whole stomach, pancreas,
spleen, portal vein, gastric artery, and gastric vein were

The Journal of Medical Investigation Vol. 66 2019

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The Journal of Medical Investigation Vol. 66 August 2019
extracted from MDCT scans and traced, and 3D images were
integrated. Since blood vessels were not automatically traced bythis software, they were identified and manually traced using
1-mm intervals from axial 2-dimensional images, followed byreconstruction of 3D images (Figure 1). Trainee surgeons made3D imaging and checked anatomical variation and positional
relationship preoperatively.

Surgery

RESULTS

Vascular pattern detected by 3D imaging
Table 1 shows the vascular patterns of gastric vessels detectedby preoperative 3D imaging. The origins of infrapyloric artery

Table 1. Vascular pattern determined by three-dimensional (3D)The number of each lymph node station was classified according to the Japanese Classification of Gastric Carcinoma (8).
Surgical indication and lymph node dissection was defined by
Japanese gastric cancer treatment guidelines 2010 (ver. 3) (9).
Standardized surgical procedures were performed by the trainee or specialist. The reconstruction method was the Billroth I,
Roux-en Y in distal gastrectomy, Billroth I in pylorus-preserving
gastrectomy, esophagogastrostomy in proximal gastrectomy,
and Roux-en Y in total gastrectomy. This study included two
trainees, who were the Board Certified Surgeon of Japan societyof surgery, Board Certified Surgeon in Gastroenterology of japan
society of gastoroentelogical surgery. Both of the trainee had
enough experience of laparoscopic surgery as an operator over
150 cases. The specialist was the qualified surgeon of Endoscopic
surgical skill qualification system (ESSQS) of Japan Society for
Endoscopic Surgery. In all cases, qualified surgeon of ESSQS
qualified surgeon participated in the surgery.

Statistical analysis
All statistical analysis was performed using statistical software (JMP 8.0.1., SAS Campus Drive, Cary, 27513 NC, USA).
Clinical variables were analyzed with the chi-square test andMann-Whitney U test. Statistical significance was defined as
p < 0.05.

imaging

Characteristic
Origin of IPA
RGEA
GDA
ASPDA
ASPDA + GDA
Not detected
Origin of LGEASPA main duct
SPA lower branch
PGA
Detected
Not detectedDistance between PGA bifurcation of SPA
Confluence of IPV
RGEV
ASPDV
Not detected
Confluence of LGV
PV
SPV
Bifurcation

No of patients (%)

64% (21)36% (12)67% (22)
33% (11)47 mm
48% (16)
30% (10)21% (7)55% (18)
39% (13)
6% (2)ASPDA : anterior superior pancreaticoduodenal artery, ASPDV : anterior superior pancreaticoduodenal vein, GDA : gastroduodenal artery, IPA : infrapyloric artery
IPV : infrapyloric vein, LGEA : left gastroepiproic artery,
LGV : left gastric vein,
SPA : splenic artery, SPV : splenic vein, PGA : posterior gastricartery, PV : portal vein

1-a

1-b

1-c

1-d

LHA

LGA

RHA
GDA

SPA

Figure 1. Three-dimensional (3D) image of gastric surgery : a) coronal view, b) laparoscopic view, c) vascularanomaly, d) complicated vasculature in splenic hilum

36% (12)24% (8)21% (7)
12% (4)
3% (1)

M. Nishi, et al. virtual 3D image for laparoscopic gastrectomy

282(IPA) (Figure 2-a) were the right gastroepiploic artery (RGEA)
in 12 cases (36%), the gastroduodenal artery (GDA) in eightcases (24%), the bifurcation of the RGEA and GDA in sevencases (21%), and not detected in one case (3%). The origins of theleft gastroepiploic artery (LGEA) (Figure 2-b) were the splenicartery (SPA) main duct in 21 cases (64%) and the SPA lower
branch in 12 cases (36%). The posterior gastric artery (PGA)
was detected in 22 cases (67%). The distance between the PGA
and the bifurcation of SPA was 47 mm. The types of confluenceof the infrapyloric vein (IPV) (Figure 2-c) were the right gastroepiploic vein (RGEV) in 16 cases (48%), the anterior superior
2-apancreaticoduodenal vein (ASPDV) in 10 cases (30%), and notdetected in seven cases (21%). The types of confluence of the left
gastric vein (LGV) (Figure 2-d) were the portal vein (PV) in 18
cases (55%), the splenic vein (SPV) in 13 cases (39%), and thebifurcation of the PV and SPV in two cases (6%).

Utility of 3D simulation as an educational tool for trainee surgeons
3D imaging is useful to know the anatomical structure suchas the vascular anomaly or complicated vasculature for example
splenic hilum (Figure 1). We used the 3D imaging for intraoperative navigation. Figure 3 shows 3D imaging and actual
2-b

PSPDA
GDA

IPA
RGEA

LGEA/V

SPA

2-c

2-d
LGV
RGEV
IPV

PV

SPV

ASPDV
ARCV

Figure 2. Vascular pattern determined by three-dimensional (3D) imaging : a) infrapyloric artery, b) left
gastroepiploic artery, c) infrapyloric vein, d) left gastric vein

3-a

3-b

RGEV

䠑
RGEV

ARCV
ARCV

3-c

3-d

PHA
LGA

RGA

PHA

CHA

SPA
GDA

Stump
of RGA

CHA

LGA

SPA

Figure 3. Three-dimensional (3D) image and actual laparosocpic view conducted by trainee surgeon a) 3D
imaging in #6 lymph node dissection, b) laparoscopic view in #6 lymph node dissection, c) 3D imaging in suprapancreatic lymph node dissection, d) laparoscopic view in suprapancreatic lymph node dissection

The Journal of Medical Investigation Vol. 66 August 2019
surgical view conducted by trainee surgeon. 3D imaging enabled
depiction of a view that was similar to that seen during actual
laparoscopic surgery. Thirty-three patients who underwent laparoscopic gastrectomy were assigned to one of two groups : thetrainee group (n = 19) or the specialists group (n = 14). Table 2
shows the patients characteristic and surgical outcomes. There
were no significant differences with regard to age, gender, bodymass index, surgical procedure, lymph node dissection, or fStagebetween trainee group using intraoperative 3D image with thespecialist in instruction group without the intraoperative 3D
image. With regard to surgical outcomes, there were no significant difference in intraoperative bleeding (trainee group : 61 ± 64
ml vs. specialists group 54 ± 42 ml), operative time (trainee
group : 385 ± 50 min vs. specialists group 379 ± 117 min), number of harvested lymph nodes, duration of postoperative hospitalstay, or mortality and morbidity between the two groups.
Table 2. Patients’ characteristic and surgical outcome
Characteristic

Trainee(n = 19)

Specialists(n = 14)

P value

Age

65 ± 1068 ± 9N.S

Gender (male/female)

12/7

10/4

N.S

22.5 ± 3.1

22.9 ± 3.5

N.S

10/6/3

6/6/2

N.S

BMI
fStage (I/II/III)
Surgical Procedure(LADG/LAPG/LATG)

15/2/2

7/2/5

N.S

D1/D1+/D2

1/11/7

1/9/4

N.S

Blood loss (ml)61 ± 6454 ± 42N.S

Operative time (min)385 ± 50379 ± 117N.S

Harvested lymph node

24.8 ± 9.3

24.2 ± 9.9

N.S

Postoperative hospital stays

15.3 ± 4.3

14.5 ± 4.2

N.S

Mortality (%)

0

0

N.S

Morbidity (%)

10.5

7.1

N.S

Stasis (%)

5.3

0Intraperitoneal abscess (%)

5.3

0

Anastomotic stenosis (%)

0

7.1

LADG : laparoscopic assisted distal gastrectomy, LAPG : laparoscopic assisted proximal gastrectomy, LATG : laparoscopic assisted total gastrectomy

DISCUSSION
The present study demonstrated the utility of preoperative
3D imaging as educational tools for laparoscopic gastrectomy bytrainee surgeons. 3D-simulation techniques contribute to a better understanding of the anatomy and any vascular anomalies.
The combination of contrast-enhanced MDCT and 3D fusion
software provided clear anatomic assessment of the gastricvasculature, stomach, pancreas, and spleen. It enabled trainee
surgeons to easily and safely perform laparoscopic gastrectomy.
Advances in imaging techniques and simulation software
now enable precise liver surgery, pancreatic surgery, and laparoscopic gastrectomy (2-7). We previously described the utility ofsimulation software for liver surgery, which enabled us to detecta venous branching pattern, venous congestion area, and thepositional relationship of the hepatic hilum for liver surgery (6,7).
With regard to pancreaticoduodenectomy, detection of inferior
pancreaticoduodenal artery (IPDA) and assessment of IPDA
ligation using 3D-CT resulted in a decrease in intraoperative
blood loss (3). For patients undergoing gastrectomy, preoperative
assessment with 3D imaging allowed identification of the left

283

gastric artery and vein, the right gastric artery, and the replaced
left hepatic artery (4, 5).
Anatomical variations of the gastric vasculature are common.
In particular, arterial variations are found in 10%-20% of cases(10). In the current study, we found IPA and IPV anomalous
variations. The origins of the IPA were the RGEA in 12 cases(36%), the GDA in eight cases (24%), the bifurcation of the RGEA
and GDA in seven cases (21%), and not detected in one case (3%).
Our findings are consistent with those from a previous study,
which showed that the origins of IPA were the GDA in 64%, the
ASPDA in 21%, the RGEA in 13%, and the posterior superior
pancreaticoduodenal artery in 2% (11). The confluence of the IPV
was the RGEV in 16 cases (48%), the ASPDV in 10 cases (30%),
and not detected in seven cases (21%). This is the first report tocharacterize the confluence of the IPV. The detection rate of IPV
was still low. The CT protocol should be improved to detect thinblood vessels. The posterior gastric artery (PGA) is very important in gastrectomy, because the PGA is the border between the
11p and the 11d lymph node (8). Further, misidentification of
PGA can lead to massive bleeding or pancreatic fistula. The PGA
was detected in 22 cases (67%) via preoperative 3D imaging. Ourdetection rate was lower than that in a previous report (12). The
distance between the PGA and the bifurcation of splenic artery
was 47 mm. This preoperative information was helpful to guide
lymph node dissection above the pancreas and to guide resectionof the PGA.
In our institute, the trainee, who have enough experience ofgastrointestinal surgery as Board Certified Surgeon of Japansociety of surgery, or Board Certified Surgeon in Gastroenterology of japan society of gastrointestinal surgery, start to perform
LG with qualified surgeon of ESSQS qualified surgeon of Japan
Society for Endoscopic Surgery. Our top-priority was patients’safety. We always consider the patients’ safety and the quality ofthe surgery, including LG.
Regarding learning curve, 40 to 60 cases are required to become proficient in laparoscopic gastrectomy (13-15). Tokunagasuggested that educational system maintained surgical quality.
Training requires sufficient experience as an assistant andscopist, standardization of the surgical procedure, and teamparticipation instructions (16-18), as suggested by experience ina high-volume center (more than 200 cases a year). However, it
might be difficult to establish an optimal educational system inthe majority of the institutes. In the current study, the operative
time and blood loss in the trainee group were comparable tothose in the specialist’s group. No major complications were observed in either group. 3D imaging generated a view that is similar to that seen during actual laparoscopic surgery. We believethat 3D imaging is a reliable educational tool for laparoscopic
gastrectomy performed by trainee surgeons.
In conclusion, preoperative 3D imaging contributed to successful and safe laparoscopic gastrectomy by trainee surgeon.

CONFLICT OF INTEREST STATEMENT
Masaaki Nishi and other co-authors have no conflict ofinterest.

ETHICAL STATEMENT AND CONSENT
All procedures followed were in accordance with the Helsinki
Declaration of 1964 and later versions. Ethics Committees’ approval is unnecessary for this study.

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