Emerging technologies to improve techniques and outcomes of robotic partial nephrectomy: striving toward the pentafecta

Partial nephrectomy for renal tumors: recommendations of the Italian Society of Urology RCC working group

INTRODUCTION

Partial nephrectomy (PN) aims to remove renal tumors while preserving renal function without affecting oncological and perioperative surgical outcomes. Aim of this paper is to summarize the current evidence on PN and to provide evidence-based recommendations on indications, surgical technique, perioperative management and postoperative surveillance of PN for renal tumors in the Italian clinical and health care system context.

EVIDENCE ACQUISITION

This review is the result of an interactive peer-reviewing process of the recent literature on PN for renal tumors carried out by an expert panel composed of members of the Italian Society of Urology (SIU) Renal Cell Carcinoma Working Group.

EVIDENCE SYNTHESIS

PN for localized renal tumors is not inferior to radical nephrectomy in terms of survival outcomes while significantly better preserving renal function. Loss of renal function after PN is influenced by medical comorbidities/preoperative renal function and surgical variables such volume of parenchyma preserved and ischemia time. Urologists should select the clamping strategy during PN based on their experience and patient-specific factors. PN can be performed with any surgical approach based on surgeon's expertise and skills. Robotic PN has the potential to expand the minimally invasive indications without interfering with oncological outcomes. The use of 3D virtual models, real time ultrasound and fluorescence tools to assess the anatomy and vascularization of renal tumors during PN may allow a more accurate preoperative planning and intraoperative guidance. Proper postoperative surveillance protocols are essential to detect tumor recurrences and assess functional outcomes.

CONCLUSIONS

PN is the standard of care for treatment of localized T1 renal tumors. Recent data supports PN also for selected T2-T3a tumors in experienced institutions. Careful preoperative planning, adequate surgical skills and volumes and appropriate postoperative management and surveillance are paramount to optimize PN oncological and functional outcomes.

A novel 3D deep learning model to automatically demonstrate renal artery segmentation and its validation in nephron-sparing surgery

Purpose

Nephron-sparing surgery (NSS) is a mainstream treatment for localized renal tumors. Segmental renal artery clamping (SRAC) is commonly used in NSS. Automatic and precise segmentations of renal artery trees are required to improve the workflow of SRAC in NSS. In this study, we developed a tridimensional kidney perfusion (TKP) model based on deep learning technique to automatically demonstrate renal artery segmentation, and verified the precision and feasibility during laparoscopic partial nephrectomy (PN).

Methods

The TKP model was established based on convolutional neural network (CNN), and the precision was validated in porcine models. From April 2018 to January 2020, TKP model was applied in laparoscopic PN in 131 patients with T1a tumors. Demographics, perioperative variables, and data from the TKP models were assessed. Indocyanine green (ICG) with near-infrared fluorescence (NIRF) imaging was applied after clamping and dice coefficient was used to evaluate the precision of the model.

Results

The precision of the TKP model was validated in porcine models with the mean dice coefficient of 0.82. Laparoscopic PN was successfully performed in all cases with segmental renal artery clamping (SRAC) under TKP model’s guidance. The mean operation time was 100.8 min; the median estimated blood loss was 110 ml. The ischemic regions recorded in NIRF imaging were highly consistent with the perfusion regions in the TKP models (mean dice coefficient = 0.81). Multivariate analysis revealed that the feeding lobar artery number was strongly correlated with tumor size and contact surface area; the supplying segmental arteries number correlated with tumor size.

Conclusions

Using the CNN technique, the TKP model is developed to automatically present the renal artery trees and precisely delineate the perfusion regions of different segmental arteries. The guidance of the TKP model is feasible and effective in nephron-sparing surgery.

New imaging technologies for robotic kidney cancer surgery

Objective

Kidney cancers account for approximately 2% of all newly diagnosed cancer in 2020. Among the primary treatment options for kidney cancer, urologist may choose between radical or partial nephrectomy, or ablative therapies. Nowadays, robotic-assisted partial nephrectomy (RAPN) for the management of renal cancers has gained popularity, up to being considered the gold standard. However, RAPN is a challenging procedure with a steep learning curve.

Methods

In this narrative review, different imaging technologies used to guide and aid RAPN are discussed.

Results

Three-dimensional visualization technology has been extensively discussed in RAPN, showing its value in enhancing robotic-surgery training, patient counseling, surgical planning, and intraoperative guidance. Intraoperative imaging technologies such as intracorporeal ultrasound, near-infrared fluorescent imaging, and intraoperative pathological examination can also be used to improve the outcomes following RAPN. Finally, artificial intelligence may play a role in the field of RAPN soon.

Conclusion

RAPN is a complex surgery; however, many imaging technologies may play an important role in facilitating it.

External Validation of a Novel Comprehensive Trifecta System in Predicting Oncologic and Functional Outcomes of Partial Nephrectomy: Results of a Multicentric Series

Background: To validate a novel trifecta for evaluating outcomes of partial nephrectomy (PN) on a multicentric dataset. Methods: Between 2007 and 2020, three renal cancer databases were queried for patients with solitary renal masses who underwent PN (n = 649). Trifecta was estimated for overall cohort and contributing centers. Overall survival (OS), cancer-specific survival (CSS) and end-stage renal disease (ESRD) probabilities were assessed by Kaplan–Meier. Cox regression was used to identify predictors of OS, CSS, ESRD. For all analyses, a p < 0.05 was considered significant. Results: At a median follow-up of 22.7 months (IQR 12.5–76.5) overall trifecta was 76.7% [Centre A; (n = 230; 68.6%), B (n = 68; 77.3%), C (n = 200; 88.4%); p = 0.001). On Kaplan–Meier, patients achieving trifecta exhibited higher OS (p = 0.024), higher CSS (p = 0.015) and lower ESRD rates (p = 0.024). On multivariable analysis, age (HR 1.04; 95% CI 1.01–1.08) and trifecta (HR 0.34; 95% CI 0.15–0.76) were independent predictors of OS while pT stage (HR 1.95; 95% CI 0.45–8.43) and trifecta (HR 0.33; 95% CI 0.16–0.67) were predictors of CSS (each p < 0.01). Preoperative CKD stage ≥ 3a (HR 13.1; 95% CI 4.07–42.6) and trifecta (HR 0.41; 95% CI 0.19–0.87) were independent predictors of ESRD (each p < 0.05). Conclusions: On external validation, trifecta was an independent predictor of all PN endpoints, regardless of hilar control and ischemia duration.

Comparison of Robot-Assisted and Laparoscopic Partial Nephrectomy for Renal Hilar Tumors: Results from a Tertiary Referral Center

Objective: To compare perioperative, functional, and oncologic outcomes between robot-assisted partial nephrectomy (RAPN) and laparoscopic partial nephrectomy (LPN) for renal hilar tumors. Methods: We retrospectively reviewed patients who underwent minimally invasive partial nephrectomy for renal hilar tumors at our institution between January 2014 and August 2018. The entire cohort was divided into two groups according to surgical approach: RAPN and LPN group. Perioperative, functional, and oncologic outcomes of the two groups were collected and compared. Results: A total of 116 patients with renal hilar tumors were identified, including 52 patients who underwent RAPN and 64 patients who underwent LPN, respectively. Demographic baseline characteristics were similar in two groups. There were no differences between the RAPN and LPN groups for operative time, transfusion rate, conversion rate, surgical margin, perioperative complication, and hospital stay. Compared with the LPN group, the RAPN group was associated with significant less estimated blood loss (100 vs 150 mL; p < 0.001), shorter warm ischemia time (20.3 vs 24.5 minutes; p = 0.001), and higher direct cost (p < 0.001). Percentage of estimated glomerular filtration rate change at 6 months after surgery was lower in RAPN group than LPN group (10.4% vs 15.2%; p = 0.020). No significant difference was observed between the two groups in terms of oncologic outcomes. Conclusions: For hilar tumors, both RAPN and LPN were safe and feasible surgical treatments. RAPN might be associated with superior perioperative outcomes (less estimated blood loss and shorter warm ischemia time) and better postoperative renal functional preservation. RAPN might be the preferred option when condition permits for renal hilar tumors.

Near-infrared fluorescence imaging for intraoperative margin assessment during robot-assisted partial nephrectomy

OBJECTIVES

To demonstrate how using a standardised dosing strategy of indocyanine green (ICG) dye with near-infrared fluorescence (NIRF) imaging can be used to differentiate renal tumours from normal renal parenchyma during robot-assisted partial nephrectomy (RAPN).

PATIENTS AND METHODS

We reviewed a prospectively collected database of 361 consecutive RAPNs using NIRF between June 2011 and March 2018, and determined the rate at which differential fluorescence was achieved. Tumour and kidney fluorescence or afluorescence were recorded intraoperatively and compared to histological results on final pathology.

RESULTS

Of 330 tumours, after 31 exclusions for nonvisible tumours due to adherent fat, completely intrarenal location or for incomplete data, 288 (87.3%) successfully exhibited differential fluorescence. Among the predominant histologies, 249 of 277 (89.9%) renal cell carcinomas did not fluoresce, as well as 23 of 32 (71.9%) oncocytomas. Real-time gross assessment of resection margin for fluorescence yielded a positive margin rate on final pathology of 0.30%.

CONCLUSION

When administered with a standardised ICG-dosing strategy, NIRF successfully achieved differential fluorescence in a large majority of tumours during RAPN with an exceedingly low positive margin rate.

Complications in robotic urological surgeries and how to avoid them: A systematic review

Objectives

To review the main complications related to the robot-assisted laparoscopic (RAL) approach in urology and to suggest measures to avoid such issues.

Methods

A systematic search for articles of the contemporary literature was performed in PubMed database for complications in RAL urological procedures focused on positioning, access, and operative technique considerations. Each complication topic is followed by recommendations about how to avoid it.

Results

In all, 40 of 253 articles were included in this analysis. Several complications in RAL procedures can be avoided if the surgical team follows some key steps. Adequate patient positioning must avoid skin, peripheral nerve, and muscles injuries, and ocular and cognitive complications mainly related to steep Trendelenburg positioning in pelvic procedures. Port-site access and closure should not be neglected during minimally invasive procedures as these complications although rare can be troublesome. Technique-related complications depend on surgeon experience and the early learning curve should be monitored.

Conclusions

Adequate patient selection, surgical positioning, mentorship training, and avoiding long-lasting procedures are essential to prevent RAL-related complications. The robotic surgical team must be careful and work together to avoid possible complications. This review offers several steps in surgical planning to reach this goal.

Current Status of Nephron-Sparing Surgery (NSS) in the Management of Renal Tumours

Nephron-sparing surgery has emerged as the surgical treatment of choice for small renal masses over the past two decades, replacing the traditional teaching of radical nephrectomy for renal cell carcinoma. With time, there has been an evolution in the techniques and indications for partial nephrectomy. This review summarizes the current status of nephron-sparing surgery for renal carcinoma and also deals with the future of this procedure.

Robotic surgery with the Da Vinci Xi: simultaneous upper and lower tract surgery

The evolution of robotic platforms has continued to advance the field and improve outcomes. We review the literature regarding the use of the Da Vinci Xi for simultaneous upper and lower tract surgery, examining outcomes. In colusion, the Xi has allowed evolution of technique and surgical outcomes.

Use of near infrared fluorescence during robot-assisted laparoscopic partial nephrectomy

BACKGROUND

Partial nephrectomy is the treatment of choice for T1a tumours. The open approach is still the standard method. Robot-assisted laparoscopic surgery offers advantages that are applicable to partial nephrectomy, such as the use of the Firefly® system with near-infrared fluorescence.

OBJECTIVE

To demonstrate the implementation of fluorescence in nephron-sparing surgery.

CASE REPORT

This case concerned a 37-year-old female smoker, with obesity. The patient had a right kidney tumour measuring 31 mm, which was found using tomography. She therefore underwent robot-assisted laparoscopic partial nephrectomy, with a warm ischaemia time of 22 minutes and the use of fluorescence with the Firefly® system to guide the resection. There were no complications. The tumour was a pT1aN0M0 renal cell carcinoma, with negative margins. Robot-assisted renal laparoscopic surgery is employed for nephron-sparing surgery, with good oncological and functional results. The combination of the Firefly® technology and intraoperative ultrasound can more accurately delimit the extent of the lesion, increase the negative margins and decrease the ischaemia time.

CONCLUSION

Near-infrared fluorescence in robot-assisted partial nephrectomy is useful for guiding the tumour resection and can potentially improve the oncological and functional results.

Comparison of the trifecta outcomes of robotic and open nephron-sparing surgeries performed in the robotic era of a single institution

Purpose

In this study we aimed to report a comparative analysis between open and robotic nephron sparing surgeries (NSS) from a single institutional database.

Methods

Patients who have undergone NSS during the robotic era of our institution were included in this study. Open (n = 74) and robotic (n = 59) groups were compared regarding trifecta outcome. Trifecta was defined as; warm ischemia time (WIT) <25 min, negative surgical margins and the absence of perioperative complications.

Results

A total of 57 (77 %) and 45 (76 %) patients in the open and robotic groups, respectively achieved the trifecta outcome. Overall trifecta rate was 77 % (n = 102/133). The only statistically significant difference between trifecta positive and trifecta negative patients was the length of hospitalization (LOH). Except LOH; none of the tested parameters were shown to be predictive of trifecta outcome on univariate and multivariate analyses. Concerning trifecta positive patients; those in the open surgery group had larger tumors with a higher degree of morphometric complexity and were hospitalized for a longer period of time. Additionally, operative duration was significantly higher in the robotic group.

Conclusions

In our cohort, no significant difference in achieving the trifecta outcome was reported after open and robotic NSS. Length of hospitalization was the only parameter that differed significantly between trifecta positive and trifecta negative patients. Surgical approach was not a significant predictor of simultaneous achievement of trifecta outcomes. Irrespective of the trifecta definition; larger and more complicated tumors were handled via open NSS.