A total of 144 patients were randomly assigned to the LPLC and SPLC groups (72 per group). After randomization, 20 patients were dropped out for various reasons, as shown in Figure 1. Finally, 124 participants were included in the analysis (62 in the LPLC group; 62 in the SPLC group). Conversion to open surgery due to severe adhesions was required in 2.8% (2/71) and 1.5% (1/68) of participants in the LPLC and SPLC groups, respectively (p = 0.759). All participants were followed up within 30 days after surgery.
Table 1 describes the patients’ demographic characteristics, laboratory test results, and cardiopulmonary comorbidities, which were nearly balanced between the 2 groups. Notably, most participants were elderly, with mean ages of 61.9 and 64.9 years in the LPLC and SPLC groups, respectively. Meanwhile, 46% had hypertension, 21% had diabetes mellitus, 35% had coronary heart disease, 10% had arrhythmias, and 15% had pulmonary emphysema. A previous history of biliary inflammation or pancreatitis was noted in 35% of patients.
Table 1. Demographic Characteristics and Cardiopulmonary Comorbidities of Enrolled Participants
|
LPLC group (n=62)
|
SPLC group (n=62)
|
P value§
|
Age (y) *
|
61.9(8.1)
|
64.9(8.4)
|
0.059&
|
Sex
Female
Male
|
33(53.2%)
29(46.8%)
|
34(54.8%)
28(45.2%)
|
0.857
|
BMI (kg/m2) *
|
24.4(3.4)
|
25.1(3.9)
|
0.290&
|
Preoperative laboratory results
|
|
|
|
Count of white blood cell (×109/L) †
|
5.97(3.03-21.98)
|
6.11(2.48-17.97)
|
0.840#
|
Hemoglobin (g/L) †
Thrombocyte (×109/L) †
Albumin (g/L) †
|
137.7(75-174)
209.5(126-466)
41.8(27-48)
|
138.0(110-165)
215.5(95-514)
42.3(32-49)
|
0.289#
0.736#
0.689#
|
Alanine aminotransferase (IU/L) †
Serum creatinine (mmol/L) †
|
20.95(6-358)
68.7(45-127)
|
42.34(8-448)
65.7(35-108)
|
0.252#
0.944#
|
Cardiopulmonary Comorbidities
|
|
|
|
Hypertension
|
26(41.9%)
|
31(50.0%)
|
0.368
|
Diabetes mellitus
|
13(21.0%)
|
13(21.0%)
|
1.000
|
Coronary heart disease
Arrhythmia
Pulmonary emphysema
Chronic bronchitis
Bronchial asthma
|
8(12.9%)
5(8.10%)
8(12.9%)
3(4.8%)
3(4.8%)
|
17(27.4%)
7(11.3%)
10(16.1%)
5(8.1%)
2(3.2%)
|
0.044
0.544
0.610
0.717¶
1.000¶
|
History of pulmonary surgery
History of cardiac or mediastinal surgery
Smoking>5 years
Liver cirrhosis
History of biliary inflammation or biliary pancreatitis
History of PTCD
History of ERCP
|
1(1.6%)
0(0)
9(14.5%)
1(1.6%)
30(48.4%)
1(1.6%)
3(4.8%)
|
1(1.6%)
2(3.2%)
6(9.7%)
0(0)
14(22.6%)
1(1.6%)
1(1.6%)
|
1.000¶
0.496¶
0.409
1.000¶
0.003
1.000¶
0.619¶
|
Values in parentheses are percentages unless indicated otherwise; *values are mean (SD); †values are median (range). BMI, body-mass index. PTCD, percutaneous transhepatic cholangial drainage. ERCP, endoscopic retrograde cholangiopancreatography. §χ2 test, except & One-way ANOVA, ¶ Fisher’s exact test and #Mann–Whitney U test.
As demonstrated in Table 2, most surgeons reported having an excellent working space and surgical view in the LPLC (90.3%) and SPLC (98.4%) groups. Meanwhile, 5 (8.1%) surgeons in the LPLC group and 1 (1.6%) in the SPLC group reported nearly excellent working conditions, whereas 1 surgeon in the LPLC group reported an unsatisfactory working space and required increased pressure. The level of surgeon comfort during surgery did not differ significantly between the groups (p = 0.114).
Table 2. Surgeon Comfort Level During Operation
Variable
|
LPLC group (n=62)
|
SPLC group (n=62)
|
P§
|
Surgeon’s comfort ¶
|
|
|
0.114
|
Level 1
|
1(1.6)
|
0(0)
|
|
Level 2
|
5(8.1)
|
1(1.6)
|
|
Level 3
|
56(90.3)
|
61(98.4)
|
|
Values in parentheses are percentages. ¶ Level 1 indicates unsatisfied with intraoperative visibility or working space, need to increase pneumoperitoneum pressure; Level 2, nearly excellent, but did not affect operation and there was no need to increase pneumoperitoneum pressure; Level 3, excellent, adequate view and working space. §Fisher’s exact test.
Table 3 displayed perioperative outcomes. The intra-abdominal operative time and estimated blood loss (EBL) showed no difference between the LPLC and SPLC groups. Bile spillage during dissection of the gallbladder bed was observed in 16 (16.1%) and 7 (11.3%) patients in the LPLC and SPLC groups, respectively (p = 0.433). Meanwhile, bile duct injuries did not occur in either group. A similar proportion of patients required a drainage tube in the 2 groups (p = 0.412). The postoperative mortality rate was 0% in both groups. No patients developed major complications such as postoperative bile leakage, intra-abdominal hemorrhage, cardiopulmonary events, or minor complications such as delayed wound healing or subcutaneous emphysema. The highest temperature on postoperative day 1 (p = 0.211), the median time to the first flatus (p = 0.853), and postoperative hospital stay (p = 0.378) showed no significant between-group differences. The difference between the mean baseline (preoperative) and postoperative VAS scores was similar in the LPLC and SPLC groups (p = 0.710).
Table 3. Perioperative Outcomes and Pathological Results
Variable
|
LPLC group (n=62)
|
SPLC group (n=62)
|
Difference (95% CI)
|
P§
|
Duration of analgesic (min) *
|
73.0(36~210)
|
77.7(30~175)
|
-4 (-10.00 ~ 6.000)
|
0.647#
|
Intra-abdominal operative time (min) *
|
49.3(10~187)
|
46.5(15~127)
|
3.5 (-7.000 ~ 10.00)
|
0.739#
|
EBL (ml) †
|
|
|
|
0.207
|
<5
|
34(54.8)
|
34(54.8)
|
-
|
|
5-20
|
23(37.1)
|
17(27.4)
|
-
|
|
>20
|
5(8.1)
|
11(17.7)
|
-
|
|
Blood transfusion
|
0(0)
|
0(0)
|
-
|
-
|
Intraoperative bile spillage
|
10(16.1)
|
7(11.3)
|
4.8 (-8.8 ~ 18.4)
|
0.433
|
Bile duct injury
|
0(0)
|
0(0)
|
-
|
-
|
Drainage placement
|
18(29.0)
|
14(22.6)
|
6.5 (-10 ~ 22.5)
|
0.412
|
Postoperative complication
|
|
|
|
|
Bile leak
|
0(0)
|
0(0)
|
-
|
-
|
Intraabdominal hemorrhage
|
0(0)
|
0(0)
|
-
|
-
|
Delayed wound healing
|
0(0)
|
0(0)
|
-
|
-
|
Subcutaneous emphysema
|
0(0)
|
0(0)
|
-
|
-
|
Cardiopulmonary events ‡
|
0(0)
|
0(0)
|
-
|
-
|
Clavien-Dindo grade III-V
|
0(0)
|
0(0)
|
-
|
-
|
Highest temperature on postoperative day one *
|
36.8(36.2~39.4)
|
36.7(36.0~39.0)
|
0 (0.000 ~ 0.2000)
|
0.211#
|
Time to fist flatus, hours *
|
22.5(9~47.5)
|
21.9(4~46.5)
|
0.75 (-2.000 ~ 2.000)
|
0.853#
|
Duration of postoperative hospital stay, days *
|
3.0(1~8)
|
3.0(1~8)
|
-
|
0.378#
|
Mortality within 30 days
|
0(0)
|
0(0)
|
-
|
-
|
VAS
|
|
|
|
|
Preoperative VAS *
|
0(0~8)
|
0(0~8)
|
0 (0~0)
|
0.209#
|
Mean postoperative VAS *
|
1.77(0.8~6)
|
1.74(0.2~4.3)
|
0.105 (-0.160 ~ 0.500)
|
0.203#
|
Mean VAS post-VAS pre *
|
1.0(-4.7~ 4.8)
|
0.8(-5.0~4.0)
|
0.17 (-0.875 ~ 0.500)
|
0.710#
|
Main postoperative pathology
|
|
|
|
|
Gallstones only
|
51(82.3)
|
48(77.4)
|
-
|
|
Gallbladder polyps with or without gallstones
|
7(11.3)
|
13(21.0)
|
-
|
|
Cholecystitis only
|
4(6.5)
|
1(1.6)
|
-
|
|
Values in parentheses are percentages unless indicated otherwise; *values are median (range). LC, laparoscopic cholecystectomy. EBL, estimated blood loss. VAS, visual analog score. †Considering the minimal blood loss during most LC procedures, EBL was categorized as grade 1 (<5 ml), grade 2 (≥5 ml and ≤20 ml), and grade 3 (>20 ml). ‡ include but not limited to angina pectoris, myocardial infarction, arrhythmia, heart failure, hypoxemia, atelectasis, pulmonary infection, pulmonary embolism, et al. § χ2 test, except # Mann–Whitney U test.
As displayed in Table 4, for the entire cohort, the postintervention pH and PaCO2 were significantly lower than the preintervention ones (p < 0.001). However, serum bicarbonate (HCO3) and base excess (BE) levels were similar before and after the intervention.
Table 4. Main Arterial Blood Gas Parameters of The Whole Cohort Before and After Intervention
Parameter
|
Pre-intervention (n=124)
|
Post-intervention (n=124)
|
Difference (95%CI)
|
P §
|
pH
|
7.401(7.320~7.519)
|
7.358(7.137~7.460)
|
0.047 (0.037~0.059)
|
<0.001
|
PaCO2
|
38.0(25.0~56.0)
|
43.1(27.0~85.3)
|
-5.2 (-6.8 ~ -3.6)
|
<0.001
|
HCO3
|
23.7(17.2~33.9)
|
24.0(16.5~33.9)
|
-0.4 (-1.2 ~ 0.3)
|
0.28
|
BE
|
-0.3(-6.0~7.5)
|
-1.1(-6.9~7.5)
|
0.6 (-0.1 ~ 1.3)
|
0.101
|
HCO3, serum bicarbonate. BE, base excess. §Mann–Whitney U test.
Table 5 presents the main ABG parameters before and after pneumoperitoneum in both groups. Preoperatively, pH, PaCO2, HCO3, lactate, and BE were balanced between the 2 groups. Postoperatively, the median PaCO2 was similar in the LPLC (43.3 mmHg) and SPLC (43.0 mmHg) groups (p = 0.988), and the pH, HCO3, and lactate levels were also similar. However, the BE was significantly higher in the LPLC group than in the SPLC group (-0.6 mmol/L [-6.9–7.5] vs -1.9 mmol/L [-6.6–5.4]; p = 0.031). Derived ABG parameters were not different between groups (p > 0.05).
Table 5. Comparison of Arterial Blood Gas Parameters Between the Two Groups
Variable
|
LPLC group (n=62)
|
SPLC group (n=62)
|
Difference (95%CI)
|
P §
|
pH pre †
|
7.41(0.04)
|
7.40(0.38)
|
-0.012 (-0.029 ~ 0.002)
|
0.08¶
|
PaCO2 pre
|
38.4(26.5~56.0)
|
38.0(25~56)
|
0.00002 (-2 ~ 2)
|
0.986
|
HCO3 pre
|
24.0(18.0~33.9)
|
23.3(17.2~30.9)
|
-0.6 (-1.7 ~ 0.4)
|
0.213
|
Lactate pre
|
1.07(0.5~2.7)
|
1.1(0.5-3.0)
|
0.00005 (-0.2 ~ 0.1)
|
0.885
|
BE pre †
|
0.219(2.58)
|
-0.490(2.56)
|
-0.7 (-1.6 ~ 0.3)
|
0.125¶
|
pH post
|
7.36(7.14~7.46)
|
7.36(7.28~7.42)
|
-0.013 (-0.03 ~ 0.003)
|
0.127
|
PaCO2 post
|
43.3(31.3~85.3)
|
43.0(27~63)
|
0.1 (-2.2 ~ 2.3)
|
0.988
|
HCO3 post
|
24.4(20~33.9)
|
23.6(16.5~31.7)
|
-0.8 (-1.7 ~ 0.2)
|
0.139
|
BE post
|
-0.6(-6.9~7.5)
|
-1.9(-6.6~5.4)
|
-0.9 (-1.8 ~ -0.1)
|
0.031
|
Lactate post
|
0.87(0.4~2.9)
|
0.95(0.5~3.0)
|
0.1 (0 ~ 0.2)
|
0.162
|
pH post/pH pre †
|
0.993(0.007)
|
0.993(0.006)
|
0 (-0.002 ~ 0.002)
|
0.813¶
|
PCO2 post/PCO2 pre
|
1.14(0.89~1.81)
|
1.13(0.69~1.80)
|
0.01 (-0.051 ~ 0.066)
|
0.857
|
HCO3 post/HCO3 pre
|
1.02(0.90~1.20)
|
1.00(0.69~1.28)
|
-0.01 (-0.031 ~ 0.014)
|
0.489
|
BE post/BE pre
|
0.97(-7~10.67)
|
1.02(-8~22)
|
0.003 (-0.389 ~ 0.354)
|
0.886
|
Lactate post/Lactate pre
|
0.81(0.39~2.36)
|
0.90(0.40~1.71)
|
0.086 (0 ~ 0.183)
|
0.065
|
pH post-pH pre
|
0.0495 (-0.2~0.1)
|
0.0445 (-0.2~0.1)
|
0.00002 (-0.017 ~ 0.016)
|
0.944
|
Values in parentheses are median (range) unless indicated otherwise; † values are mean (SD). HCO3, serum bicarbonate. BE, base excess. § Mann–Whitney U test, except ¶Student’s t test.