Comparison of Outcomes and Surgical Time Between Cortical and Medullary Suture vs. Medullary-Only Suture: Cortex Clinical Trial, From 2025 to 2027
Phase: NA
Conditions: RCC, Renal Cell Cancer
Sponsor: Brazilian Institute of Robotic Surgery

 
 
 
 
 
 
 
 
COMPARISON OF OUTCOMES AND SURGICAL TIME BETWEEN CORTICAL 
AND MEDULLARY SUTURE VERSUS MEDULLARY-ONLY SUTURE: CORTEX 
CLINICAL TRIAL 
14/09/2025 
 
NCT number: Not available 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 
Brief Summary 
This randomized, prospective, blinded clinical trial will compare two renorrhaphy 
techniques in robot-assisted partial nephrectomy: medullary-only suture (single layer) 
versus cortical and medullary suture (two layers). The study will evaluate estimated 
blood loss, renal function, warm ischemia time, complication rates, operative efficiency, 
and hospital length of stay. 
Study Design 
• 
Study Type: Interventional (Clinical Trial) 
• 
Allocation: Randomized (1:1) 
• 
Intervention Model: Parallel Assignment 
• 
Masking: Participant, postoperative care physician, data collectors, and 
statisticians (surgical team not blinded) 
• 
Primary Purpose: Treatment 
• 
Estimated Enrollment: 80 participants 
• 
Study Start Date: March 2025 
• 
Estimated Primary Completion Date: March 2027 
Official Title 
Comparison of Outcomes and Surgical Time Between Cortical and Medullary Suture 
Versus Medullary-Only Suture: CORTEX Clinical Trial 
Conditions 
Renal Cell Carcinoma; Renal Mass Requiring Partial Nephrectomy 
Interventions 
• 
Experimental: Medullary-only suture 
Robot-assisted partial nephrectomy using single-layer medullary suturing with 
3-0 absorbable monofilament poliglecaprone 25 (Caprofyl™), with early 
unclamping. 

• 
Active Comparator: Cortical and Medullary suture 
Robot-assisted partial nephrectomy using two-layer suturing (3-0 Caprofyl™ for 
medullary layer plus 0 Vicryl™ for cortical layer after early unclamping). 
Primary Outcome Measure 
• 
Estimated Blood Loss 
Volume of blood loss measured intraoperatively. 
Time Frame: During surgery (intraoperative period). 
Secondary Outcome Measures 
• 
Renal Function (eGFR) 
Estimated glomerular filtration rate using CKD-EPI at baseline and at 
postoperative day 1, 2 weeks, 2 months, and 5 months. 
Time Frame: Baseline, Day 1, 2 weeks, 2 months, and 5 months 
postoperatively. 
• 
Percentage of Renal Volume Loss 
Difference between preoperative and postoperative renal volume measured on 
imaging. 
Time Frame: 4 months postoperatively. 
• 
Warm Ischemia Time 
Duration of renal artery clamping during surgery. 
Time Frame: Intraoperative (minutes of arterial clamping). 
• 
Complications (hematuria, pseudoaneurysm, urinary fistula) 
Incidence of intra- and postoperative complications. 
Time Frame: From surgery through 5 months postoperatively. 
• 
Console Time 
Duration from docking to undocking of the robotic system. 
Time Frame: Intraoperative. 
• 
Length of Hospital Stay 
Number of days from surgery to hospital discharge. 
Time Frame: From day of surgery until hospital discharge. 
• 
Conversion to Open Surgery 
Number of cases converted to open surgery. 
Time Frame: Intraoperative. 
• 
Postoperative Quality of Life (WHOQOL-BREF) 
Score on WHOQOL-BREF questionnaire. 
Time Frame: 2 months and 5 months postoperatively. 
 
 

Eligibility Criteria 
Inclusion Criteria: 
• 
Age ≥18 years 
• 
Indication for robot-assisted partial nephrectomy due to renal mass diagnosed on 
CT 
• 
ECOG performance status ≤1 
• 
Negative pregnancy test within 24 h preoperatively for women of childbearing 
potential 
• 
Written informed consent 
Exclusion Criteria: 
• 
Solitary kidney 
• 
Multiple or bilateral renal masses (if operated simultaneously or within <4 
months) 
• 
GFR <30 mL/min/1.73m² or grade ≥2 hepatic/renal toxicity 
• 
Bleeding diathesis or inability to maintain anticoagulation 
• 
Participation in another experimental trial within 30 days 
• 
Significant acute or chronic conditions compromising safety or study 
compliance 
Study Locations 
Mater Dei Hospital, Salvador, Bahia, Brazil 
Santa Izabel Hospital – Santa Casa, Salvador, Bahia, Brazil 
Statistical Analysis 
Descriptive statistics for all variables. Student’s t-test or Wilcoxon for continuous 
variables; chi-square or Fisher’s exact test for categorical variables. Multiple logistic 
and linear regression analyses for adjusted associations. p<0.05 considered significant. 
Statistical software: R version 4.4.2. 
Arms and Interventions 
Arm/Group 
Intervention Name Intervention Description 
Experimental: 
Medullary-only 
Suture 
Medullary-only 
suture (Caprofyl™ 
3-0) 
Robot-assisted partial nephrectomy using 
single-layer medullary suturing with 3-0 
absorbable monofilament poliglecaprone 
25 (Caprofyl™) and early unclamping. 

Arm/Group 
Intervention Name Intervention Description 
Active Comparator: 
Cortical and 
Medullary Suture 
Cortical + 
Medullary suture 
(Caprofyl™ + 
Vicryl™) 
Robot-assisted partial nephrectomy using 
two-layer suturing (3-0 Caprofyl™ for 
medullary layer plus 0 Vicryl™ for cortical 
layer after early unclamping). 
 
 
 
 
 
Outcome Measures Table (PRS-ready) 
Title 
Description 
Time Frame 
Safety 
Issue? 
Estimated Blood Loss 
(Primary Outcome) 
Volume of blood lost during 
surgery, measured 
intraoperatively using suction 
canisters and swab weight. 
During surgery 
(intraoperative period) No 
Renal Function (eGFR) 
Estimated glomerular 
filtration rate (CKD-EPI) at 
baseline and at postoperative 
time points. 
Baseline, Day 1, 2 
weeks, 2 months, and 5 
months postoperatively 
No 
Percentage of Renal 
Volume Loss 
Difference between 
preoperative and 
postoperative renal volume 
measured by imaging. 
4 months 
postoperatively 
No 
Warm Ischemia Time 
Duration of renal artery 
clamping during surgery in 
minutes. 
Intraoperative 
No 
Complications 
(hematuria, 
pseudoaneurysm, 
urinary fistula) 
Incidence of intra- and 
postoperative complications 
recorded from medical 
records. 
From surgery through 
5 months 
postoperatively 
Yes 
Console Time 
Duration from robotic 
docking to undocking. 
Intraoperative 
No 

Title 
Description 
Time Frame 
Safety 
Issue? 
Length of Hospital Stay Number of days from surgery 
to hospital discharge. 
From day of surgery 
until hospital discharge No 
Conversion to Open 
Surgery 
Number of cases converted 
from robotic to open surgery. Intraoperative 
No 
Postoperative Quality 
of Life (WHOQOL-
BREF) 
Score on WHOQOL-BREF 
questionnaire assessing 
quality of life. 
2 months and 5 months 
postoperatively 
No