Cop+Ed+fisse 2006 165Archivio Italiano di Urologia e Andrologia 2020; 92, 3 ORIGINAL PAPER No conflict of interest declared. DOI: 10.4081/aiua.2020.3.165 my. Gill et al. demonstrated that LPN was a viable alter- native for treating selected renal tumour patients (3). Moreover, in last decades, indications for LPN have pro- gressively extended to tumors of greater diameter and stage (pT1b) (4). For these reasons, many preoperative score systems have been proposed in order to estimate the pre-operative risk, based on computed tomography (CT) scan and mag- netic resonance imaging (MRI). Most commonly used are the PADUA (5) score and the RENAL system (6) score. Both trans and retro peritoneal approach are commonly used by surgeons with the comparable surgical and functional outcomes (7), although the retro peritoneal access, on the one hand guarantees a more restricted working space and a worse exposure of the medial kid- ney facia, on the other, it allows an immediate access to the renal vessels and reduces the risk of injury to the intra peritoneal organs. The increasingly extreme use of partial nephrectomy is in terms of the size of the treated masses and of the comorbidity of the patients subjected to this procedure (solitary kidney, synchronous bilateral tumors, etc.) jus- tifies the attention to the oncological and functional result, also in consideration of learning curves. Surgical results were evaluated using MIC-criteria (margin, ischaemia and complications) (8) that anticipated the Trifecta-criteria (9). The only difference between the two score-systems is the length of ischaemia time (20 vs 25 minutes). Herein, we report on postoperative outcomes of a single surgeon, single centre series of retroperitoneal LPN, in order to assess the correlation between pre- operative parameters, including the individual nephro- metric PADUA score, and post-operative outcomes, including MIC score, in order to provide an evaluation for surgical risk evaluation also related to the surgeon experience. PATIENTS AND METHODS We designed a monocentric, single surgeon retrospective nonrandomized study. A total of 147 patients, who under- went retroperitoneal LPN for malignancy from March 2014 to April 2018, were enrolled. All the anonymously collected data have been retrospectively evaluated. All procedures were performed by a single surgeon with a Objectives: To evaluate surgical outcomes in a series of laparoscopic retroperitoneal partial nephrectomies. Methods: A total of 147 patients who underwent laparoscopic retroperitoneal partial nephrectomy by a single surgeon were evaluated. Pre-operative parameters (body mass index, ASA score, tumour size, cTNM stage, PADUA score risk, surgeon experience) and intraoperative and postoperative outcomes (operative mean time, warm ischemia time, blood loss, transfu- sion rate, length of hospitalization, and margin-ischaemia- complications [MIC] success rate) were considered. Results: For 134 patients (91.1%) the success of the treatment, defined by a MIC = 3, was obtained. When the statistical sig- nificance of each of the independent variables was tested, sur- geon’s experience added statistical significance to the predic- tion of operative time (p = 0.000), warm ischemia time (p = 0.000) and blood loss (p = 0.000); tumour size (p = 0.046) to the prediction MIC (p = 0.010), operative time (p = 0.000), warm ischemia time (p = 0.003) and blood loss (p = 0.010); ASA score to the length of hospitalization (p = 0.009). Conclusions: Laparoscopic retroperitoneal partial nephrectomy represents an adequate and safe technique for the treatment of T1 renal cancer. Optimal MIC success rate can be achieved, although intraoperative outcomes tend to be related to the learning curve even in a very experienced laparoscopic sur- geon. Length of hospitalization depends on general health con- dition of patients. KEY WORDS: Laparoscopy; Partial nephrectomy; Kidney neo- plasms; Retroperitoneal; PADUA score. Submitted 10 May 2020; Accepted 11 May 2020 INTRODUCTION Over the past few years, both robotic and laparoscopic partial nephrectomy (LPN) have emerged as a strong alter- native to open partial nephrectomy due to several docu- mented advantages including less blood loss, quicker recovery, less complications (1). In 2006, Carini et al. presented their successful results of their long-term follow-up study of post-operative out- comes after open partial nephrectomy for pT1a tumours (2). The Authors show favourable results as a cancer-spe- cific survival (CSS) of 96.7% and 94.7% at, respectively, 5 and 10 years, with a progression-free survival (PFS) of 96% and 94% at 5 and 10 years, respectively. Just 1.5% of patients developed a local recurrence, with no distant metastasis, far from the site of the previous tumorecto- Predictors of surgical outcomes of retroperitoneal laparoscopic partial nephrectomy Summary Carmine Sciorio 1, Pier Paolo Prontera 2, Salvatore Scuzzarella 1, Paolo Verze 3, Lorenzo Spirito 3, Lorenzo Romano 3, Alberto Trinchieri 4 1 Urology Unit, Manzoni Hospital, ASST Lecco, Lecco, Italy; 2 Urology Unit, S.S. Annunziata Hospital, ASL Taranto, Taranto, Italy; 3 Department of Urology, University of Naples Federico II, Naples, Italy; 4 Urology Department, IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milano, Italy. 01Sciorio_Stesura Seveso 24/09/20 14:10 Pagina 165 Archivio Italiano di Urologia e Andrologia 2020; 92, 3 C. Sciorio, P.P. Prontera, S. Scuzzarella, P. Verze, L. Spirito, L. Romano, A. Trinchieri 166 previous long-lasting experience in renal laparoscopy. Exclusion criteria were as follows: a) distant metastases at the time of the diagnosis; b) previous retroperitoneal sur- gery. Informed consent was administered and preopera- tive abdominal CT scan and/or MRI were performed for all patients in order to assess maximum lesion diameter and clinical TNM staging (10). Preoperative PADUA score (5) for each patient was calculated after the CT scan or MRI evaluation performed by two different radi- ologists, considering the site of the lesion (polar or non- polar), the extension (exophytic/endophytic), the loca- tion at the equator (lateral/medial), the involvement of the renal hilum and the excretory pathway. Tumours were stratified in low (PADUA score: 6-7), medium (PADUA score: 1-2) and high risk (PADUA score: =/>10). Age, gender, body mass index (BMI), American Society of Anesthesiologists (ASA) score, comorbidities (such as dia- betes and hypertension), blood loss, operative time (tro- cars-in to trocars-out), warm ischemia time, conversion rate to open surgery, pathological stage, tumour histo- type according to the classification of the World Health Organization (WHO), nuclear grading according to Fuhrman's classification (11) and surgical margins involvement have been evaluated. Peri and post-opera- tive complications (within the first 30 days) have also been recorded and classified in minor and major accord- ing to the Clavien-Dindo system (12) (grade 1-2 and 3- 4 respectively). The surgeon's experience was assessed by dividing surgical procedures into 6 chronological groups according to his learning curve. Finally, the successful rate for each procedure was esti- mated using validate M.I.C. system (8) (which considers ischemia time less than 20 minutes, absence of surgical margins involvement and no major post-operative com- plication). According to this trifecta system, each patient has received from 1 to 3 points. A descriptive statistical analysis of emerged data was per- formed. The continuous variables were reported as mean values and standard deviation while the categorical vari- ables were reported as the number of cases (n°) and per- centage (%) and their differences were correlated with the Pearson x². Multiple linear logistic regression was used to evaluate the predict effect of a set of pre-operative parameters (age, gender, BMI, ASA, tumour size, TNM stage, PADUA score and surgeon’s experience) on different surgical out- comes as MIC, blood loss, transfusion rate, operative time, warm ischemia time and length of hospitalization. All data were analysed using SPSS software and a p-value < 0.05 was defined as statistically significant. RESULTS A total of 147 patients (101 male and 46 female), who underwent retroperitoneal LPN from 2014 to 2018, were retrospectively enrolled Mean age was 63 years (range 37-74). Table 1 shows the baseline cohort characteristics and pre- operative data.The assessed mean diameter of renal lesions at pre-operative CT scan was 3.55 cm +/-1.65. Application of PADUA score system allow to stratify the surgical risk as follows: 79 (54% of the population) as low risk, 51 as intermediate risk (35%) and 17 as high risk (11%). Intraoperative and postoperative results are shown in Table 2. In 82 cases (56%) no ischemia was performed, whereas 64 patients received some warm ischemia time. In detail, 51 patients (35%) underwent less than 20 min- utes warm ischemia, 10 (7%) from 20 to 29 minutes and 3 (2%) more than 30 minutes of warm ischemia. The global mean time of warm ischemia was 6.84 +/- 8.74 minutes. Peri-operative complication rate was 1.4% and there was no case of conversion to open surgery. Average hospitalization time was 6.01 +/- 5.43 days. Pathological analysis of the lesions shows a prevalence of pT1a stage tumours (64%), followed by pT1b (19.7%). Pathological stages pT2 and pT3 all together represent 2.7% of the cohort and 20 lesions (13.6%) appear to be no-clear cells tumours (CCT). No positive surgical mar- gin was observed. In our purpose, the success of the treatment was defined by MIC = 3, and it was obtained in 134 patients (91.1%). At multiple linear logistic regression PADUA score, TNM stage (Table 4), tumour size by pre-operative CT, BMI, ASA and surgeon’s experience predicted the effect of MIC success (p = 0.034), operative time (p = 0.000), warm ischemia time (p = 0.000), blood loss (p = 0.000) and length of hospitalization (p = 0.002). Coefficient of deter- mination R2 explain 10.7%, 34.7%, 26.7%, 23.4% and 16.2% of the variability of MIC success, operative time, Table 1. Baseline cohort characteristics and preoperative evaluations (147 pts). Median age, years 63 (37. 64) M/F ratio (pts) 101/46 BMI (kg/m2) 25.9 ± 3.2 Right/left side (pts) 83 (57%)/64 (43%) Average volume of lesions (radiological evaluation) 3.55 ± 1.65 cm PADUA score - Low 6-7: 79 pts (54%) - Intermediate 8-9: 51 pts (35%) - High ≥ 10: 17 pts (11%) Tumor site (polar/not polar) 99 pts. (67%)/48 pts. (33%) Tumor site (exophytic/not exophytic/completely endophytic) 82 pts (56%)/56 pts (38%)/9 pts (6%) Tumor site (lateral/medial) 90 pts (61%)/57 pts (39%) Renal sinus involvement (yes/no) 8 pts (5%)/139 pts (95%) Excretory system involvement (yes/no) 6 pts (4%)/141 pts (96%) Table 2. Intraoperative parameters of the cohort (147 pts). Average operative time (min) 118 ± 35 Warm ischemia (pts) - no ischemia 82 (56%) - < 20 minutes 51 (35%) - 20–29 minutes 10 (7%) - > 30 minutes 3 (2%) Average time of warm ischemia (min) 6.84 ± 8.74 Average blood loss (ml) 236 ± 186 Average hospital stay (day) 6.01 ± 5.43 Average n° of transfusions per patient 0.16 ± 0.65 Percentage of transfused patients 7.5% (11/147) Percentage of major complications 1.4% (2/147) 01Sciorio_Stesura Seveso 24/09/20 14:10 Pagina 166 warm ischemia time, blood loss and length of hospitaliza- tion. When the statistical significance of each of the inde- pendent variables was tested, surgeon’s experience added statistical significance to the prediction of operative time (p = 0.000), warm ischemia time (p = 0.000) and blood loss (p = 0.000); tumour size (p = 0.046) to the prediction MIC (p = 0.010), operative time (p = 0.000), warm ischemia time (p = 0.003) and blood loss (p = 0.010); ASA score to the length of hospitalization (p = 0.009). For 13 patients (8.9%) with MIC < 3, failure was associ- ated in a statistically significant way to lesion diameter (p = 0.000), TNM classification >/= pT1b (72.7% vs 95.7%) (p = 0.000), high risk calculated by PADUA score system (p = 0.006) (Table 3). Moreover, for all patients with MIC < 3 we registered significantly longer times of warm ischemia (p = 0.000), longer operating times (p = 0.000) and greater blood loss (p = 0.002). For all no-CCT MIC was 3, with a successful rate of 100%. DISCUSSION The main goal of the present study was to evaluate the MIC score rate in our series of patients treated by retroperitoneal LPN. Secondary endpoints were the assessment of the correla- tion between pre-operative parameters, as PADUA score, and perioperative and postoperative outcomes. The successful rate obtained was elevate (MIC = 3 was obtained in 91,1% of patients), comparable to that of Gill's group (13) and to that of other robotic case studies (14). Evaluation of some recent series excluded patients who had not undergone ischemia. By applying this criterion, our success rate would drop, although it should be under- lined that in our series ischemia was not used even in many cases with high PADUA score and large diameter tumors. The exclusion of these patients from the study would be penalizing for the evaluation of our results. On the other hand, the MIC evaluation resulted in a “flatten- ing” of the results range upwards. For this reason, in our opinion, the indicators of surgical success should be more stratified, for example by rewarding the absence of ischemia or very low ischemia times (< 10 minutes). It is interesting to note that the learning curve for the examined procedure is long even for an experienced sur- geon. In fact, the results obtained by a single surgeon, already an expert at the beginning of this experience, show a specific trend, with a significant improvement in periop- erative and postoperative outcomes during the study peri- od. However, the results in terms of MIC are not signifi- cantly related to the experience of the surgeon, who, when he has sufficient initial experience in renal laparoscopy, is able to ensure the surgical success of the procedure even with longer operating times and a higher blood loss and transfusion rate. On the other hand, in the initial phase of the experience the surgeon tends to select cases with lower PADUA score (6-7), while in the continuation of the study were then considered more complex cases with higher PADUA score (> 10). More studies are needed to better investigate these relationships and provide the surgeon, both expert and on learning curve, with effective predictive tools to obtain the best results in terms of operative and oncological out- comes. The use of the traditional laparoscopic technique for par- tial retroperitoneal nephrectomy has disadvantages and advantages over the robot-assisted technique. Numerous studies have compared the results of traditional laparo- scopic partial nephrectomy (LPN) with those of robotic- assisted partial nephrectomy (RAPN). Transperitoneal and retroperitoneal RAPN are equally effective and safe in terms of warm ischemia time, estimated blood loss, rate of conversion and complications and positive surgical margins (15). In particular, retroperitoneal RALPN proved to be an excellent option for posterior and later- al tumors with reduced operational times and shortened lenghts of stay (16). Some Authors reported that RAPN has short operating and ischemia times and less blood loss compared with LPN (17, 18), although other studies have shown no dif- ferences in terms of operative time, warm ischemia time, estimated blood loss and lenght of hospital stay (19, 20). A meta-analysis showed equivalent peri-operative out- comes of LPN and RAPN, which added the advantage of a shorter warm ischaemia time (21). On the other hand, LPN implies lower healthcare costs and use of sutureless technique can reduce warm ischemia and operative time (22, 23). At the moment, the two techniques represent excellent 167Archivio Italiano di Urologia e Andrologia 2020; 92, 3 Surgical outcomes of RPN Table 4. Correlation between surgical outcomes and pathological stage. pT1a pT1b pT2 pT3 Others P-value Mean PADUA score 7.41 ± 1.42 8.48 ± 1.7 9.50 ± 3.53 8 ± 0.0 7.35 ± 1.38 0.000 Average time of ischemia 6.01 ± 7.71 11.62 ± 11.45 0 9.5 ± 13.43 4.25 ± 6.4 0.011 Pathological tumor size (cm) 2.78 ± 1.07 4.71 ± 1.66 5.25 ± 5.3 5.75 ± 4.59 2.88 ± 1.24 0.000 MIC=3 (pts) 90/94 20/29 2/2 2/2 20/20 0.000 Table 3. Patient characteristics with and without MIC success (defined as MIC = 3). Patients characteristics MIC success (134 pts) MIC failure (13 pts) P-value Average volume of lesions (radiological evaluation) 3.38 ± 1.58 5.30 ± 1.34 0.000 PADUA score Pts: Pts: - 6-7 75 4 0.006 - 8-9 47 4 - ≥ 10 12 5 Tumor site Pts: Pts: - Exophytic 80 2 0.007 - Not exophytic 47 9 - Completely endophytic 7 2 pTNM Pts: Pts: - pT1a 90 4 0.000 - pT1b 20 9 - pT2 2 0 - pT3 2 0 - Others 20 0 Tumor size (histopathological evaluation) 3.08 ± 1.5 cm 4.97 ± 1.47 cm 0.000 Average time of warm ischemia (min) 5.16 ± 6.96 24.07 ± 6.14 0.000 Average operative time (min) 115 ± 32 151 ± 51 0.000 Blood loss (ml) 222 ± 155 385 ± 360 0.002 01Sciorio_Stesura Seveso 24/09/20 14:10 Pagina 167 Archivio Italiano di Urologia e Andrologia 2020; 92, 3 C. Sciorio, P.P. Prontera, S. Scuzzarella, P. Verze, L. Spirito, L. Romano, A. Trinchieri 168 alternatives to the in the management of moderate to complex renal tumours with high PADUA scores. CONCLUSIONS Retroperitoneal LPN represents an adequate and safe technique for the treatment of T1 renal cancer. Optimal MIC success rate can be achieved, although intraopera- tive outcomes tend to progressively improve during the learning curve even in a very experienced surgeon. Length of hospitalization depends on general health con- dition. REFERENCES 1. de Castro Abreu AL, Cacciamani G, Gill IS. Partial Nephrectomy. In: Sotelo R., Arriaga J, Aron M. (eds) Complications in Robotic Urologic Surgery. Springer, 2018; pp. 163-173. 2. Carini M, Minervini A, Masieri L, et al. Simple enucleation for the treatment of PT1a renal cell carcinoma: our 20-year experience. Eur Urol. 2006; 50:1263-8. 3. Gill IS, Desai MM, Kaouk JH, et al. Laparoscopic partial nephrec- tomy for renal tumor: duplicating open surgical techniques. J Urol. 2002; 167:469-7. 4. Ljungberg B, Albiges L, Bensalah K, et al. EAU Guidelines for Renal Cell Carcinoma. Edn. presented at the EAU Annual Congress Copenhagen 2019. 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BJU Int. 2013; 111:256-63. 20. Simsek A, Yavuzsan AH, Colakoglu Y, et al. Comparison of robotic and laparoscopic partial nephrectomy for small renal tumours. Arch Ital Urol Androl. 2017; 89:93-96. 21. Zhang X, Shen Z, Zhong S, et al. Comparison of peri-operative outcomes of robot-assisted vs laparoscopic partial nephrectomy: a meta-analysis. BJU Int. 2013; 112:1133-42. 22. Corongiu E, Grande P, Di Santo A, et al. Safety and efficacy of retroperitoneal sutureless zero ischemia laparoscopic partial nephrectomy for low nephrometry score masses. Arch Ital Urol Androl. 2019; 91:157-162. 23. Tiscione D, Cai T, Luciani LG, et al. Sutureless laparoscopic par- tial nephrectomy using fibrin gel reduces ischemia time while pre- serving renal function. Arch Ital Urol Androl. 2019; 91:30-34. Correspondence Carmine Sciorio, MD (Corresponding Author) carmine.sciorio@gmail.com Salvatore Scuzzarella, MD s.scuzzarella@libero.it ASST “A. Manzoni” Hospital - Lecco (Italy Pier Paolo Prontera, MD pierpaolo.prontera@virgilio.it ASL-TA “S:S. Annunziata Hospital - Taranto (Italy) Paolo Verze, MD pverze@gmail.com Lorenzo Spirito, MD lorenzospirito@msn.com Lorenzo Romano, MD loryromano@hotmail.it Università Federico II - Napoli (Italy) Alberto Trinchieri, MD alberto.trinchieri@gmail.com Urology Department, IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milano (Italy) 01Sciorio_Stesura Seveso 24/09/20 14:10 Pagina 168