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- Material and Methods
- Conflict of Interest
Partial nephrectomy (PN) is the standard treatment for renal tumours < 7 cm. Laparoscopic PN (LPN) can avoid the morbidity associated with flank incision and provides oncological efficacy equivalent to that of open PN [1, 2]; however, owing to technical challenges, in particular tumour excision and renorraphy, LPN has remained limited to tertiary care centres . Recently, robotic assistance has been proposed, with the aim of decreasing the technical difficulty of LPN through wristed instrumentation and three-dimensional vision [4, 5].
Numerous centres have reported their experience of robot-assisted LPN (RALPN) [6, 7]. RALPN has been proven to be safe and reproducible , yields similar oncological results to those of LPN and, in most series, is associated with shorter ischaemia time [9-11].
Postoperative complications occurring after PN are a major concern that might explain the underuse of nephron-sparing surgery to treat small renal tumours . Several factors, related to the patient (anticoagulant treatment, obesity), the tumour (tumour size or location, nephrometry score) or the surgeon (experience, type of access, clinical environment) can influence postoperative outcomes [13, 14]. In older study series, LPN was associated with a higher rate of postoperative complications compared with open PN . The enhanced precision and skills provided by robotic assistance may confer a better quality of renal repair and thus facilitate laparoscopic surgery for more complex tumours.
Currently, the complication rates reported for RALPN are similar to those observed for LPN [11, 16]. As robot-assisted surgery is steadily increasing worldwide, RALPN has become common practice in many countries. Our objective was to identify the factors that predict postoperative complications in a large multicentre series of patients undergoing RALPN.
- Top of page
- Material and Methods
- Conflict of Interest
Laparoscopic partial nephrectomy has been reported to reduce the morbidity associated with flank incision. Expert teams showed there were benefits with regard to blood loss, postoperative pain and length of stay [23, 24], but these benefits came at the cost of higher complication rates and longer ischaemia times . Technical difficulties have probably hampered the development of LPN, which remained mostly performed at tertiary care centres. Over the last 10 years, robotic assistance has emerged and this has overcome the technical complexity of LPN. Several series have been reported to date showing that RALPN was feasible and reproducible [6, 25]. Moreover, RALPN could have a benefit regarding renal function preservation; a recent meta-analysis showed that RALPN yielded similar results to those of LPN regarding postoperative and oncological outcomes but was associated with a reduced ischaemia time .
The present study specifically focused on postoperative complications after RALPN. To our knowledge, three multicentre series have reported such information to date (Table 6 [13, 25, 26]). Overall, we had a 30% complication rate and we found that global complications wereprincipally affected by surgeon's experience and blood loss.
Table 5. Surgical and medical complications in the cohort
|Clavien grade||Medical complications||Surgical complications|
|Thromboembolism||Myocardial infarction||Other||Haematoma||Pseudoaneurysm||Urinary fistula||Infection||Other|
Table 6. Postoperative complications in the multicentre RALPN series
|Authors||Year||No. of centres||No. of patients||Complication rate||Major complications||Classification used|
|Benway et al. ||2009||3||129||8.50%||NS||NS|
|Spana et al. ||2011||4||450||14.40%||3.80%||Clavien/Dindo|
|Ficarra et al. ||2012||4||347||11.80%||2.90%||Clavien/Dindo|
We defined surgeon's experience using a somewhat arbitrary threshold of 20 RALPN procedures, as reported by other publications [27, 28]. Based on that limit, we observed a clear learning curve with a complication rate of 37% among surgeons during their first 20 cases, dropping to 29% after 20 cases. In multivariate analysis, having performed >20 cases reduced the risk of complications by half. Similarly, Ficarra et al.  recently showed that surgical experience was an independent predictor of overall complication after RALPN and Mottrie et al.  showed that surgeon's experience was correlated to robot console time and duration of warm ischaemia; however, the learning curve for RALPN is expected to be minimal for a surgeon who has a significant experience of LPN .
Major complications (i.e. ≥ grade III) occurred in 10% of the cases and were mostly haemorrhagic complications (i.e. perirenal haematoma, false aneurysm or arterio-venous fistula). In multivariate analysis, the main predictor of major complications was the opening of the collecting system (HR: 3.0). Surprisingly, tumour complexity, evaluated using the R.E.N.A.L. score, had no influence, which contrasts with the results of a recent publication . Nevertheless, opening of the collecting system and blood loss can be seen as indirect signs of tumour complexity and technical difficulties during surgery that can influence postoperative outcomes. The impact of nephrometry scores on postoperative complications is not clear. Some authors found that tumour complexity had no impact on on postoperative outcome [29, 30], while others found that it did have an impact [8, 13, 14, 31]. We had a low proportion of highly complex tumours (3.5%) and it is possible that retrospective analysis of imaging in several institutions might have translated into misclassification. Another explanation is that the present series reflects the beginning of RALPN experience in France and therefore there might be a selection by surgeons of easily resectable tumours.
Robotic systems offer enhanced vision and several degrees of freedom that make it easier to repair renal parenchyma after tumour excision. It seems logical that better and faster repair would mean fewer complications postoperatively. It is not certain, however, that these enhanced skills translate into fewer complications compared with LPN. In the meta-analysis by Aboumarzouk et al. , complication rates did not differ between LPN and RALPN, but most of the comparative series included in this meta-analysis were of small size or from single centres [6, 9-11]. Benway et al.  compared 129 consecutive RALPNs with 118 consecutive LPNs in a multi-institutional study and found similar complication rates between the two procedures (8.6 vs 10.2%, respectively), but those authors did not use the Clavien system. Conversely, in a recent single-centre study, Mullins et al.  compared 102 LPN cases vs 105 RALPN cases, performed by the same surgeon and found fewer complications among patients who underwent robot-assisted surgery (4.8 vs 11.8%; P = 0.006).
The present study has some limitations. Most of the patients had tumours of low complexity, which reflects the nature of the population selected to be included in the initial experience of RALPN. Such a selection may have underestimated the impact of nephrometry score as a predictor of complications, as reported in other studies . The study includes a large collection of data from six different centres with the inherent biases associated with large retrospective studies. LPN was commonly performed in all involved institutions before they started using the robot and, therefore, our results can be considered preliminary and additional follow-up and increased numbers of patients are required.
In conclusion, in the present study, RALPN was associated with a significant risk of, mostly minor, postoperative complications. The factors influencing postoperative course were surgeon's experience, blood loss and opening of the collecting system. Longer follow-up and additional prospective studies are needed to confirm these findings. With growing experience and progress in surgical techniques, we may in the future observe a reduction in the frequency of postoperative complications.