Table 1 Definition of secondary endpoints

 Feasibility of recruitment

Recruitment goal of n = 80 patients within 18 months.

 Costs (€)

Procedure-related costs and all inpatient hospital costs up to POD 90.

 Duration of surgery (min)

RPD: from the start of positioning of the robot to the end of skin closure.

OPD: from the beginning of skin incision to the end of skin closure.

 Blood loss (ml)

As recorded in the anaesthesiology report.

 Serious intraoperative complications

Any untoward medical/surgical occurrence that results in death, is life-threatening, requires prolongation of existing hospitalisation or results in persistent or significant disability/incapacity. Intraoperative in this context is defined as from the beginning of anaesthesia until the end of skin closure.

 Conversion rate (%)

Conversion rate from robotic to open surgery.

 Surgeon’s mental workload/stress

Self-evaluation according to the National Aeronautics and Space Administration Task Load Index [27] at the end of surgery.

 Rate of complete margin clearance in patients with malignant tumours

a. Microscopically complete margin clearance > 0.1 cm margin clearance, R0 (CRM−).

b. Microscopic margin clearance ≤ 0.1 cm, R0 (CRM+).

c. Microscopic margin involvement (R1) resections according to the 8th edition of the UICC TNM classification.

 Lymph nodes in patients with malignant tumours

a. Number of lymph nodes resected.

b. Number of tumour-positive lymph nodes.

 Mortality (%)

From the day of surgery until postoperative day 90.

 Quality of recovery

Measured via the quality of recovery questionnaire QoR-15 [28], assessed at baseline and on POD 4.

 Time to functional recovery (days)

Up to postoperative day 90; defined as: independently mobile at the preoperative level, sufficient pain control with oral medication alone, ability to maintain sufficient (i.e. > 50%) daily required caloric intake by mouth, no intravenous fluid administration and no signs of infection [29].

 Total length of intensive care unit stay (days)

From the day of index operation up to postoperative day 90.

 Length of hospital stay (days)

From the day of index operation up to the day of discharge.

 Rate of superficial and deep surgical site infections (SSIs)

As defined by the Centres of Disease Control and Prevention (CDC) within 30 days [30]. Organ-space SSIs are excluded from this measurement as they are independent of surgical access, but rather depend on the underlying surgery. Consequently, organ-space SSIs will be recorded in the overall complication rate if applicable.

 Pancreas-specific complications

Rate and severity within 90 days of:

a. Postoperative pancreatic fistula as defined by the ISGPS [31].

b. Postpancreatectomy haemorrhage as defined by the ISGPS [32].

c. Delayed gastric emptying as defined by the ISGPS [33].

d. Biliary leak as defined by the ISGLS [34].

e. Chyle leak/lymphatic fistula as defined by the ISGPS [35].

 Non-surgical re-interventions

Number of non-surgical re-interventions within 90 days after PD (e.g. image-guided drain placement, angiography with stenting/other interventions, endoscopy).

 Re-operations

Number of re-operations within 90 days after PD.

 Hospital re-admissions

Number of hospital re-admissions within 90 days after PD.

 Pain

Pain scores at rest and during movement according to the Numeric Rating Scale (NRS) on POD 2 and 4.

 Health-related quality of life (HRQoL)

Measured by the SF-36 at baseline, 30 and 90 days after index operation [36].