Developments in kidney tumor nephrometry

Comparison of the efficacy of robotic-assisted retroperitoneal laparoscopy and traditional retroperitoneal laparoscopy in partial nephrectomy among patients with renal tumors: A retrospective cohort study

PURPOSE

The efficacy of robotic-assisted retroperitoneal laparoscopy (RARL) and traditional retroperitoneal laparoscopy (TRL) in patients undergoing partial nephrectomy for treatment of a renal tumor were compared in this study.

MATERIALS AND METHODS

The retrospective study reviewed patients with renal tumors who underwent partial nephrectomy in our hospital between January 2020 and February 2022. According to different surgical methods, the patients were enrolled into the RARL (experimental group, n=65) or the TRL (control group, n=63) partial nephrectomy group.

RESULTS

One hundred twenty-eight patients were reviewed. The number of patients with collecting system injuries in the experimental group (19 cases) was significantly less than in the control group (32 cases; p<0.05). The operative time (115.7±48.2 min vs. 143.1±25.5 min) and heat ischemia time (18.7±4.9 min vs. 26.4±5.2 min) were significantly shorter in the experimental group than in the control group. The intraoperative blood loss (35.4±13.2 mL vs. 96.1±34.3 mL) and postoperative drainage volume (55.9±26.4 mL vs. 75.2±32.6 mL) were significantly less in the experimental group than in the control group (p<0.05). The change in postoperative glomerular filtration rate decrease in the experimental group was significantly lower than that in the control group (p<0.05). The change level in postoperative creatinine increase in the experimental group were significantly lower than those in the control group (p<0.05). There were no considerable differences in other clinical indicators or follow-up results between the two groups.

CONCLUSIONS

RARL was superior to TRL for renal tumor treatment with respect to operative time, intraoperative blood loss, warm ischemia time, and postoperative renal function recovery.

RENAL nephrometry scoring system in bilateral Wilms tumor: predictive application

AIM

This study aims to explore the application of RENAL nephrometry scoring system in bilateral Wilms tumor (BWT).

METHODS

A retrospective review of patients with BWT from January 2010 to June 2022 was performed. Each kidney unit of the BWT was evaluated independently and scored according to RENAL nephrometry scoring system by 2 blinded reviewers, and reviewers were blinded to what surgery the patients ultimately had. Discrepancies were evaluated by a third reviewer to reach a consensus. Tumor anatomical characteristics were summarized and compared.

RESULTS

29 patients with 53 kidney units were included in the study. 53 kidney units included 12 (22.6%) low-complexity, 9 (17.0%) intermediate-complexity, and 32 (60.4%) high-complexity. 2 kidney units (3.8%) had tumor thrombus, and 14 (26.4%) had multiple lesions. A total of 42 kidney units (79.2%) underwent initial nephron-sparing surgery (NSS) and 11 (20.8%) underwent radical nephrectomy. Less complexity tumors were observed in the NSS group. Of the 42 kidney units undergoing initial NSS, 26 were performed in vivo and 16 ex vivo via autotransplantation. The latter group featured a higher complexity. During follow-up, 22 patients survived and 7 died, no statistically significant tumor complexity was observed between the two groups.

CONCLUSIONS

The anatomical characteristics of BWT are complex. Despite this study did not indicate that the complexity correlates with prognosis, low-complexity tumors were candidates for NSS, and kidney autotransplantation provided a feasible procedure for high-complexity tumors. A refined system is required due to multiple lesions and tumor thrombus.

A pilot study investigating the feasibility of using a fully automatic software to assess the RENAL and PADUA score

PURPOSE

Image-based morphometric scoring systems such as the RENAL and PADUA scores are useful to evaluate the complexity of partial nephrectomy for renal cell carcinoma (RCC). The main aim of this study was to develop a new imaging software to enable an automatic detection and a 3D visualization of RCC from CT angiography (CTA) and to address the feasibility to use it to evaluate the features of the RENAL and the PADUA scores.

METHODS

A training dataset of 210 patients CTA-scans manually segmented was used to train a deep learning algorithm to develop the automatic detection and 3D-visualization of RCC. A trained operator blindly assessed the RENAL and PADUA scores on a testing dataset of 41 CTA from patients with RCC using a commercialized semi-automatic software (ground truth) and the new automatic software. Concordance between the two methods was evaluated.

RESULTS

The median PADUA score was 9 (7-11) and the renal score was 8 (5.5-9). The automatic software enabled to automatically detect the tumoral kidney and provided a 3D-visualization in all cases, with a computational time less than 20 seconds. Concordances for staging the anatomical features of the RENAL scores were respectively: 87.8% for radius, 85.4% for exophytic rate, 82.9% for location to the polar lines and 92.7% for the antero-posterior location. For the PADUA scores, concordances were 90.2% for tumor size, 85.4% for exophytic rate, 87.8% for polar location and 100% for renal rim.

CONCLUSION

By enabling an automatic 3D-visualization of tumoral kidney, this software could help to calculate morphometric scores, save time and improve reproducibility for clinicians.

LEVEL OF EVIDENCE: 4

A Literature Review of Renal Surgical Anatomy and Surgical Strategies for Partial Nephrectomy

CONTEXT

A detailed understanding of renal surgical anatomy is necessary to optimize preoperative planning and operative technique and provide a basis for improved outcomes.

OBJECTIVE

To evaluate the literature regarding pertinent surgical anatomy of the kidney and related structures, nephrometry scoring systems, and current surgical strategies for partial nephrectomy (PN).

EVIDENCE ACQUISITION

A literature review was conducted.

EVIDENCE SYNTHESIS

Surgical renal anatomy fundamentally impacts PN surgery. The renal artery divides into anterior and posterior divisions, from which approximately five segmental terminal arteries originate. The renal veins are not terminal. Variations in the vascular and lymphatic channels are common; thus, concurrent lymphadenectomy is not routinely indicated during PN for cT1 renal masses in the setting of clinically negative lymph nodes. Renal-protocol contrast-enhanced computed tomography or magnetic resonance imaging is used for standard imaging. Anatomy-based nephrometry scoring systems allow standardized academic reporting of tumor characteristics and predict PN outcomes (complications, remnant function, possibly histology). Anatomy-based novel surgical approaches may reduce ischemic time during PN; these include early unclamping, segmental clamping, tumor-specific clamping (zero ischemia), and unclamped PN. Cancer cure after PN relies on complete resection, which can be achieved by thin margins. Post-PN renal function is impacted by kidney quality, remnant quantity, and ischemia type and duration.

CONCLUSIONS

Surgical renal anatomy underpins imaging, nephrometry scoring systems, and vascular control techniques that reduce global renal ischemia and may impact post-PN function. A contemporary ideal PN excises the tumor with a thin negative margin, delicately secures the tumor bed to maximize vascularized remnant parenchyma, and minimizes global ischemia to the renal remnant with minimal complications.

PATIENT SUMMARY

In this report we review renal surgical anatomy. Renal mass imaging allows detailed delineation of the anatomy and vasculature and permits nephrometry scoring, and thus precise, patient-specific surgical planning. Novel off-clamp techniques have been developed that may lead to improved outcomes.

Waterjet dissection for partial nephrectomy without hilar clamping in a porcine model

Hilar clamping is typically used in partial nephrectomy to control hemorrhage, which may damage the renal tissue under warm ischemia conditions. The purpose of this study was to evaluate waterjet technology in partial nephrectomy without renal hilar vascular control in a porcine model. Bilateral partial nephrectomy using waterjet was performed in 8 pigs (16 kidneys: 8 for wedge resections, 8 for pole resections). The operations were performed successfully in all animals. The mean dissection time was 30.6 ± 2.9 minutes for pole resections and 36.5 ± 3.5 minutes for wedge resections. The mean blood loss was 51.6 ± 11.7 mL for pole resections and 38.7 ± 9.2 mL for wedge resections. The novel waterjet technique provided precise and effective hydrodissection of the kidney, avoiding damage to the vascular structures or collecting system.

Advancements in laparoscopic partial nephrectomy: expanding the feasibility of nephron-sparing

Partial nephrectomy (PN) offers equivalent oncologic outcomes to radical nephrectomy (RN) but has greater preservation of renal function and less risk of chronic kidney disease and cardiovascular disease. Laparoscopic PN remains underutilized likely because it is a technically challenging operation with higher rates of perioperative complications compared to open PN and laparoscopic RN. A review of the latest PN literature demonstrates that recent advancements in laparoscopic approaches, imaging modalities, ischemic mitigating strategies, renorrhaphy techniques, and hemostatic agents will likely allow greater utilization of LPN and expand its usage to increasingly more complex tumors.

Application of a standardized anatomical classification in a Chinese partial nephrectomy series

OBJECTIVE

Preoperative aspects and dimensions used for an anatomical classification is a standardized system to assess the anatomical complexity of renal tumors and its impact on perioperative outcomes of partial nephrectomy. The objective is to apply the preoperative aspects and dimensions used for an anatomical classification in a series of Chinese patients undergoing open or laparoscopic partial nephrectomy.

METHODS

A total of 195 consecutive renal tumors treated with open partial nephrectomy or laparoscopic partial nephrectomy between June 2008 and May 2011 were included in this analysis. All the preoperative images and clinical records were retrospectively evaluated. Complication rate, warm ischemia time, operation time and degree of blood loss were compared among different risk groups (low risk: preoperative aspects and dimensions used for an anatomical score 6-7; intermediate risk: preoperative aspects and dimensions used for an anatomical score 8-9; high risk: preoperative aspects and dimensions used for an anatomical score ≥10). The original preoperative aspects and dimensions used for an anatomical score system was modified by replacing rim location with hilar vasculature involvement and tested for prediction of overall complications.

RESULTS

The median preoperative aspects and dimensions used for an anatomical score was 8. Overall complication rate was 17.9%. Preoperative aspects and dimensions used for an anatomical score was an independent predictor for perioperative complications. Intermediate and high-risk patients had a four- and 37-fold higher risk of complications respectively (P = 0.012, P < 0.001). Higher preoperative aspects and dimensions used for an anatomical score predicted longer operation time (P = 0.007), warm ischemia time (P < 0.001) and higher degree of blood loss (P = 0.003) in open partial nephrectomy patients. In laparoscopic partial nephrectomy patients, preoperative aspects and dimensions used for an anatomical score was also a predictor for warm ischemia time (P = 0.033); however, it was not significant for operation time and degree of blood loss (P = 0.325, P = 0.302). The modified preoperative aspects and dimensions used for an anatomical score was an independent predictor for overall complications (P < 0.001); however, its superiority could not be verified (P = 0.847).

CONCLUSIONS

The preoperative aspects and dimensions used for an anatomical classification predicts the risk of overall complications in Chinese patients undergoing nephron-sparing surgery. Replacing the rim location with hilar vasculature involvement might be a promising modification of this scoring system.