Renal volume matters: Assessing the association between excisional volume loss and renal function after partial nephrectomy

Early Postoperative Outcomes of Retroperitoneal Partial Nephrectomy of Anterior and Posterior Renal Tumors: A Five-year Experience in A Single Center

OBJECTIVE

Partial nephrectomy (PN) is one of the surgical treatment options for renal tumors. Therefore, the aim of this study was to compare the surgical outcomes of retroperitoneal PN for anterior and posterior tumors.

MATERIALS AND METHODS

This study enrolled 177 patients who had renal tumors that were detected on abdominal computed tomography and underwent PN between January 2017 and April 2021. Tumor position was defined by the anatomic avascular Brodel's line. Surgical outcomes were compared between approaches using the chi-squared, Student's t-tests, logistic regression analysis and stratification analysis.

RESULTS

Of the 177 patients, 97 (54.8%) patients had anterior renal tumors and 80 (45.2%) had posterior renal tumors. On comparing the surgical results between the two groups, the anterior group had higher levels of hemoglobin (Hb) reduction (-1.92 g/dL vs. -1.54 g/dL, p = 0.0444), but the estimated blood loss showed no significant difference between the two groups (497.6 mL vs. 433.2 mL, p = 0.4149). In addition, the alter in estimated glomerular filtration rate (eGFR) at post-operative 1st day (p = 0.5616), 6th month (p = 0.5046) and at post-operative 1st year (p = 0.7085) were not significantly different between the two groups. Other surgical outcomes, such as blood transfusion rate, complications, and lengths of stay, also had no significant difference. Stratified analysis revealed the anterior renal tumors had a 3.76 times risk (p = 0.0186) than the posterior tumors for decreasing Hb > 10% under laparoscopic PN. No post-operative gastrointestinal-related complications were reported.

CONCLUSIONS

This study demonstrated retroperitoneal surgical access to renal tumors and revealed equivalent surgical outcomes for both anterior and posterior renal tumors. Moreover, anterior renal tumors had benefits under robotic PN for bleeding control. Retroperitoneal PN can be considered a good approach for both anterior and posterior renal tumors with few intra-abdominal complications.

Parenchymal Mass Loss During Partial Nephrectomy: Role of Devascularized Parenchymal Mass and Excised Parenchymal Mass and Impact on Functional Preservation

This study included 93 patients with renal masses who underwent standard partial nephrectomy or tumor enucleation. After surgery, parenchymal mass loss caused by devascularization resulted in more damage to renal function than excised parenchymal mass loss. Surgeons should seek better techniques to decrease devascularization during reconstruction.

INTRODUCTION

To evaluate the importance of devascularized parenchymal mass(DPM) and excised parenchymal mass(EPM) in functional preservation after standard partial nephrectomy(SPN).

PATIENTS AND METHODS

Forty-one patients who underwent pure tumor enucleation(TE) and 52 patients who underwent SPN with necessary data were included. As no EPM was lost in TE, the TE samples were used to estimate the degree of volume shrinkage that occurred when the measurements were performed in vivo with blood flow versus ex vivo without, and the shrinkage ratio was calculated as specimen volume divided by tumor volume in vivo. In SPN, the specimen volume comprised tumor volume plus EPM. The EPM was calculated as specimen volume divided by shrinkage ratio minus tumor volume in vivo. The DPM was defined as total ipsilateral parenchymal mass loss minus EPM. T tests, χ² test, and Mann-Whitney U tests were employed to compare clinical characteristics. Multivariate analysis was used to identify variables that correlated with glomerular filtration rate(GFR) preservation.

RESULTS

The mean sizes of devascularized and excised parenchymal masses were 13.6 cm³ and 5.2 cm³ (P = .01), which accounted for 7.8% and 3.4% of preoperative ipsilateral parenchymal mass (P = .03) in SPN, respectively. The shrinkage ratio was 0.71 and correlation coefficient was 0.965. After stepwise regression, DPM, and preoperative GFR were significantly associated with global GFR preservation.

CONCLUSION

The DPM comprises most of parenchymal mass loss after SPN and plays a more important role than EPM on functional outcomes. Surgeons should pay more attention to reducing devascularization during partial nephrectomy.