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Mari et al. Mini-invasive Surg 2024;8:7 https://dx.doi.org/10.20517/2574-1225.2023.103 Page 3 of 10

discerned. Points, varying from zero to two, were allocated depending on the robustness of the healthy renal
boundary extracted concomitant with the tumor (absence of visibly discernible healthy renal boundary
versus a slim healthy renal boundary versus an abundant healthy renal boundary). Thereafter, the
comprehensive resection technique (RT) was categorized into enucleation (SIB grade 0-2), enucleoresection
(SIB grade 3-4), or resection (SIB grade 5). Surgical indications were characterized as elective (localized
singular RCC with a normal opposite kidney), relative (localized singular RCC with concomitant conditions
such as diabetes, hypertension, and lithiasis that might potentially influence renal functionality in
subsequent periods), and imperative (bilateral synchronous tumors, multiple tumors, moderate to severe
chronic kidney disease, or in scenarios of malignancy compromising an anatomically or functionally
solitary kidney).

The Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) Classification of Renal
Tumors was used to evaluate the nephrometric complexity of each renal mass. All research activities in this
study involving human participants adhered to the ethical standards of our institution and national research
guidelines and were consistent with the 1964 Helsinki Declaration and subsequent amendments. Every
participant in the study gave informed consent.

Pathological evaluation and outcome
Surgical specimens were processed based on the standard practices at our institution, evaluated by expert
uropathologists. Each specimen underwent a detailed examination, including marking the surgical margins
(SMs) with ink and assessing the tumor’s size, color, and gross appearance. There was no centralized review
of pathological slides.

The primary objective of this study was to determine the incidence and identify factors predicting PSMs
after RAPN. In the assessment of SMs, specimens underwent preservation in 10% buffered fixative. These
were then subjected to extended macroscopic examination. Parameters such as dimensions, chromatic
features, and overall appearance (ranging from solidified to vesicular) were documented. The SM was
delineated using a colorant solution. Following the meticulous segmentation of the tumor, sections were
derived to secure tissue fragments from the tumor site, uninvolved tissue, and adjacent surgical boundaries.
Additional fragments encompassing the tumor, organ protective layer, and surrounding adipose tissue were
incorporated. A margin was designated as positive if tumor cells interacted with the colorant. Conversely,
the margin was classified as non-affirmative when malignant renal structures were absent from the
colorant-marked boundaries. The neoplasms underwent hierarchical categorization, in line with the criteria
[12]
established by the American Joint Committee on Cancer tumor, node, metastases classification standards .
Statistical analysis
For statistical purposes, descriptive statistics were obtained, reporting medians [and interquartile ranges
(IQR)] for continuous variables and frequencies and proportions for categorical variables, as appropriate.
Multivariable logistic regression models considering factors significantly related to margins status at
univariable analysis were applied to analyze predictors of PSMs. Statistical significance in this study was set
as P < 0.05. All reported P values are 2-sided. Two different multivariable models were built, including
various baseline clinical and intraoperative surgical features. Analyses were performed using Statistical
Package for Social Sciences (SPSS) version 29.0.2.0 (SPSS Inc, Chicago, IL).

RESULTS
From the 1,611 patients analyzed, Table 1 presented the demographic and clinical characteristics, with 1,120
(69.5%) males and 491 (30.5%) females. The median age was 62.6 years, with an IQR of 54.7 to 72.0 years.