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Wong et al. Hepatoma Res 2021;7:45 https://dx.doi.org/10.20517/2394-5079.2021.28 Page 3 of 11

For cirrhotic patients, only those with Child-Pugh class A or selected ones with Child-Pugh Class B were
deemed suitable candidates. Liver function was assessed by liver biochemistry, platelet count, and
9
indocyanine green clearance rate. Patients with inadequate platelet count (< 40 × 10 /L for minor
9
hepatectomies or < 80 × 10 /L for major hepatectomies), indocyanine green clearance rate greater than 20%
at 15 min, gross ascites, or oesophageal varices were not offered resection.

All hepatectomies were performed by a single team of dedicated liver surgeons led by at least one consultant
specialist. Both open and laparoscopic operations were performed in a standardized approach. Patients with
significant medical risk factor will be transferred to intensive care unit (ICU) or high dependency unit
postoperatively for monitoring until condition stabilized.

Operative technique
In a laparoscopic liver resection, the patient was placed in the French position with primary surgeon
standing between the legs and one assistant on either side. A 30° telescope was introduced with open cut-
down technique. Pneumoperitoneum was maintained at 12-14 mmHg. Further 2 to 4 working ports were
inserted under direct vision. Ultrasound examination was performed intra-operatively for confirmation of
location, size, and number of lesions. Cavitron Ultrasonic Surgical Aspirator® (CUSA; Valleylab, Boulder,
CO, USA) was used for liver parenchymal transection. Large vessels and bile duct branches were clipped
and divided, whereas large segmental branches of hepatic vein were divided by endovascular staplers. The
specimen was retrieved in a bag through a Pfannenstiel incision. Abdominal drain was not routinely placed.
Pressure of CO in the peritoneum will be decreased to 8 mmHg and arterial systolic blood pressure will be
2
increased to around 120 mmHg to check for bleeding. Haemostasis was achieved with bipolar diathermy,
argon beam coagulator, clips, sutures, and haemostatic patches [10,12] .

In an open hepatectomy, the patient was laid in supine position. A right subcostal incision with sternal
extension was employed. Intraoperative ultrasound and liver parenchymal transection were performed in a
similar manner with laparoscopic resection. Pringle manoeuvre was not performed routinely unless severe
bleeding was encountered. The placement of an abdominal drain was not routine .
[13]
Liver segment and liver resection was defined using Couinaud classification and Brisbane classification in
2000, respectively . Postoperative morbidity and mortality were assessed at 90 days after surgery according
[14]
to the Clavien-Dindo classification .
[15]
Statistical analysis
The baseline characteristics of patients were expressed as medians with range for continuous variables, or as
frequency with percentage for categorical variable. The Mann-Whitney U test was used for comparison of
continuous variables, and Pearson’s chi-square test was used for comparing discrete variables. The primary
outcome measured was survival, while secondary outcomes were operative time, intraoperative blood loss,
blood transfusion requirement, postoperative complications, and length of hospital stay. Survival analysis
was performed on disease-free survival versus disease recurrence or death. The Kaplan-Meier method was
used to compute survival, and the log-rank test was used for survival comparison.

Prior to comparison, data on baseline demographics, surgical characteristics and pathological findings were
compared with univariate analysis to assess the clinical difference between the laparoscopic and the open
groups. Propensity score analysis model was adopted to eliminate bias from case-match selection. Variables
with potential influence on the outcomes were assigned propensity scores after logistic regression analysis.
With propensity score computed, the nearest neighbours in the laparoscopic and open group were matched