Impact of learning curve on perioperative outcomes of off-clamp minimally invasive partial nephrectomy: propensity score matched comparison of outcomes between training versus expert series
Objective
Minimally invasive (MI) Off-Clamp partial nephrectomy (OC-PN) is a challenging surgical procedure. Training
programs in this specific surgical field are difficult to realize due to the significant risks of intraoperative bleeding with potential impact on achieving negative
surgical margins. The aim of this study was to compare perioperative outcomes of patients treated with MI-OC-PN by either a training or an expert surgeon in the
same Institution.
Materials and Methods
The prospectively maintained “renal cancer” database was queried for “off-clamp, minimally invasive, partial nephrectomy”. Overall, data of 372 patients treated between January 2015 and September 2017 were collected. A 1:2 propensity score matched (PSM) analysis was used to generate two populations homogeneous for the following variables: patient demographics (age, gender, BMI); ASA score; tumor size; PADUA nephrometry score; preoperative hemoglobin, preoperative eGFR. Exclusion criteria for propensity score analysis included multiple tumors (17), preoperative estimated glomerular filtration rate (eGFR) <30 ml/min (14), lacking PADUA score (26), single setting multiple surgeries (9), leaving 286 control cases in the expert cohort available for selection. Perioperative outcomes of first 20 patients treated by the training surgeon were compared against 40 PSM selected patients treated by an expert surgeon who have previously performed more than 1000 OC-PN. The training surgeon had previously performed more than 200 minimally invasive prostatectomies and 45 laparoscopic radical nephrectomies.
Results
Patients treated by the expert surgeon had significantly larger tumors (4.1 vs 2.9, p=0.007), lower incidence of low (≤7) PADUA nephrometry scores (30.1% vs 60%, p=0.029) and higher incidence of comorbidities (ASA score 3-4 27.3% vs 5%, p=0.03). After applying the PSM, the two cohorts were homogeneous for all preoperative variables (all p>0.18, Table 1). Patients treated by training surgeon had higher hemoglobin at discharge (12.4 vs 11.4 g/dL, p= 0.03) and significantly lower incidence of transfusion rates (0 vs 10%) but comparable incidence of hospital stay (4.9 vs 4.6 d, p=0.71), severe complications according to Clavien classification system (5% vs 5%), positive surgical margins (0% vs 2.5%, p=0.47) and eGFR at discharge (78.6 vs 73.4 mL/min, p=0.49, Table 2). Hilar clamping was never necessary in both selected cohorts (0% vs 0%, p=1.00)
Discussions
Minimally invasive (MI) Off-Clamp partial nephrectomy (OC-PN) is a challenging surgical procedure, with concerns about surgical training [1]. The impact of learning curve on outcomes of MI-OC-PN is negligible after completion of a proper training in minimally invasive surgery.
Conclusion
The impact of learning curve on outcomes of MI-OC-PN is negligible after completion of a proper training in minimally invasive surgery.
Reference
1. Does training of fellows affect peri-operative outcomes of robot-assisted partial nephrectomy?
Khene ZE, Peyronnet B, Bosquet E, Pradère B, Robert C, Fardoun T, Kammerer-Jacquet SF, Verhoest G, Rioux-Leclercq N, Mathieu R, Bensalah K.
BJU Int. 2017 May 2. doi: 10.1111/bju.13901