Baseline Characteristics and Clinicopathological Variables of Patients
Out of the total 145 patients included in this retrospective series, 119 patients were in the OPD group, and 26 patients were in the MIPD group (Six patients underwent RPD and 20 patients underwent LPD). Baseline characteristics and clinicopathological outcomes are presented in Table 1. The mean age of patients in MIPD group was higher than those in the OPD group (71.03±8.8 and 64.40±11.7 years, P=0.008). Patients in the MIPD group also had poor performance status (P=0.036) and less number of harvested lymph nodes (14.23±8.04 vs. 19.83±9.71, P=0.04). Similar male-to-female ratio, ASA, tumor size, previous abdominal surgery, rate of preoperative biliary drainage, and underlying comorbidity was found between two groups. Details of pathologic outcomes are also listed in Table 1.
Short-term postoperative outcomes of patients
Table 2 shows surgical data and short-term postoperative outcomes of the two groups. Patients in the MIPD group had significantly longer surgical time (540 vs. 462 mins, p=0.011), shorter POHS (18 vs. 24 days, p=0.001), and earlier complete drain removal (16 days vs. 22 days, p<0.001). The overall conversion rate in the MIPD group was 11.1%. There was no significant difference in EBL, postoperative ICU stay, time of initiation of oral diet and ambulation, total parenteral nutrition (TPN) dependence, and 30-days re-admission rate. Occurrence of surgical mortality, major complications and rates of POPF, DGE, and PPF were similar between OPD and MIPD groups.
Overall comparison between MIPD and OPD in elderly patients
The baseline characteristics and short-term postoperative outcomes in elderly patients are presented in Tables 3 and 4. In this cohort, 20 elderly patients underwent MIPD while 66 underwent OPD. Significantly shorter POHS (18 days vs. 24 days, P=0.014) and earlier complete drain removal (16 days vs. 22 days, p=0.004) was observed in elderly patients who underwent MIPD. The occurrence of DGE was significantly less in MIPD group (10% vs. 33%, P=0.042). There was no significant difference in parameters of sex, ASA score, EBL, harvested lymph nodes, and other short-term postoperative outcomes. Similar rate of major complications, POPF and PPF was found between two groups. No death was reported in elderly patients who underwent MIPD; however, the mortality rate in the OPD group was 9.1% (p=0.193)
Propensity score-matched comparison of elderly patients who underwent MIPD and OPD
A one-to-two PSM analysis was applied (17 patients in the MIPD group and 34 patients in the OPD group), adjusted for sex, age, CCI and pathologies, as shown in Tables 3. Although poor preoperative performance status was observed in patients underwent MIPD (P=0.042), the MIPD group still presented significantly shorter POHS (18 days vs. 25 days, p=0.028), earlier complete drain removal (16 days vs. 21 days, p=0.012) and less rate of DGE (5.9% vs. 34.2%, P=0.036) than the OPD group. There were no significant differences in surgical time, EBL, initiation of oral diet and ambulation, postoperative ICU stay, and re-admission rate. Despite the analysis did not achieve statistical significance, the pulmonary complications (0% in the MIPD group vs. 17.6 % in the OPD group, P=0.075) and mortality (0% in the MIPD group vs. 11.8 % in the OPD group, p=0.186) tended to be more common in the OPD group.
Analysis of Six Surgical Mortality Cases in OPD group
The details of 6 mortality cases in our study were revealed in Table 5. All of our mortality cases were over 65-year-old. 3 patients was died of pulmonary complication (2 Nosocominal pneumonia and 1 aspiration pneumonia), 2 patients died of IAI with septic shock and 1 died of uncontrolled PPH. Relatively longer mean operation time (507.5 mins), increased mean EBL (591.6ml), high DGE rate, high POPF rate and late ambulation was also observed in these cases.