Laparoscopic Partial Nephrectomy: Technique and Outcomes

Split renal function after treatment of small renal masses: comparison between radiofrequency ablation and laparoscopic partial nephrectomy

BACKGROUND

Radiofrequency ablation (RFA) and laparoscopic partial nephrectomy (LPN) are used to treat small renal masses (SRM; ≤4 cm), although there are conflicting results in the changes in creatinine and estimated glomerular filtration rate (eGFR) after treatment. On contrast-enhanced computed tomography (CE-CT) images, the quantity and quality of renal function can be evaluated by calculating the split renal function (SRF).

PURPOSE

To compare renal function after RFA or LPN treatment of SRMs through evaluation of the SRF in the affected kidney.

MATERIAL AND METHODS

Single T1a renal tumors successfully treated with RFA (n = 60) or LPN (n = 31) were retrospectively compared. The SRF was calculated on pre-treatment CE-CT images and the first follow-up exam after completed treatment. Serum creatinine and eGFR values were collected simultaneously. To compare renal function outcomes, Student's t-test and multivariable linear regression models (adjusted to RFA/LPN treatment, pre-treatment SRF/eGFR, BMI, age, tumor characteristics, and Charlson Comorbidity Index) were used.

RESULTS

SRF was reduced in both groups, although reduction was greater in the LPN group (LPN -5.7%) than in the RFA group (RFA -3.5%; P = 0.013). After adjusted analysis, the LPN group still had greater SRF reduction (difference 3.2%, 95% confidence interval 1.3-1.5; P = 0.001). There was no difference between groups in the change of creatinine/eGFR after treatment.

CONCLUSION

Both RFA and LPN are nephron-sparing when treating SRMs. However, in this series, reduction of SRF in the affected kidney was smaller after RFA, having a more favorable preservation of renal function than LPN.

Need for intraoperative ultrasound and surgical recommendation for partial nephrectomy: correlation with tumor imaging features and urologist practice patterns

PURPOSE

This study aimed to evaluate the need for intraoperative ultrasound (IOUS) and recommendation for surgical approach in the resection of renal tumors through a survey of practicing urologists, with correlation to tumor imaging features and urologist practice pattern.

MATERIALS AND METHODS

An institutional review board-approved retrospective review, compliant with the Health Insurance Portability and Accountability Act, of 44 renal tumors that underwent laparoscopic partial nephrectomy at the study institution was performed. The numeric component of the RENAL nephrometry score (radius [diameter], % exophytic, nearness [to collecting system/renal sinus], location) was calculated for each case using preoperative computed tomography/magnetic resonance imaging. Five anonymized images of each tumor were presented to 4 academic urologists with varying practice patterns. Reviewers independently scored each case for its need for IOUS, for recommendation of a surgical technique, and for the difficulty of the proposed surgery.

RESULTS

The RENAL scores were as follows: RENAL 1 (low complexity, score 4-6; n = 19); RENAL 2 (moderate complexity, score 7-9; n = 23); RENAL 3 (high complexity, score 10-12; n = 2). The only RENAL score component significantly influencing need for IOUS was percentage exophytic (P = 0.00002). There was an inverse relationship between normalized and averaged need for IOUS and percentage exophytic (P < 0.0001). The predominant influence for recommendation of surgical method was the reviewer him/herself, with each reviewer's recommendations closely matching his/her practice pattern. Size and percentage exophytic represented the only tumor features significantly (P = 0.03) influencing surgical recommendation.

CONCLUSIONS

There was a significant difference in the perceived need for IOUS and surgical recommendation when 4 academic urologists reviewed a series of renal masses requiring resection. Percentage exophytic correlated inversely with need for IOUS. Urologist's practice pattern and tumor size and percentage exophytic were most predictive of surgical recommendation.