Overview
This study aims to find out which surgical position is safer and works better for patients candidate to robot-assisted partial nephrectomy (RAPN) - a minimally invasive procedure to remove a small kidney tumor while preserving healthy kidney tissue.
During this operation, the patient can be placed in two different positions:
- the standard flank position, where the patient lies on their side
- a newer supine position, where the patient lies on their back using a technique called Supine Anterior Retroperitoneal Approach (SARA).
Both approaches are performed using the Da Vinci® Single Port (SP) robotic system, a state-of-the-art surgical robot that allows the operation to be done through a single small incision.
The traditional flank position has been used for many years, but it can be uncomfortable for patients and may increase the risk of certain anesthetic or nerve-related complications, especially in people with higher body weight. The new supine SARA technique could make surgery faster, safer, and less painful, but it has not yet been tested in a randomized study.
This is the first clinical trial designed to directly compare these two approaches in patients with small and localized kidney cancers (tumors ≤7 cm, stage cT1).
The study will include 124 patients treated at ASST Grande Ospedale Metropolitano Niguarda in Milan, Italy - a leading center in robotic urologic surgery.
Description
Study Objectives
Primary Objective:
To compare the outcomes of RAPN performed with the SARA approach versus the standard flank approach in achieving a "trifecta outcome," defined as:
- No intraoperative adverse events;
- Negative (cancer-free) surgical margins;
- Hospital discharge on postoperative day 1.
Secondary Objectives:
- To compare both approaches according to the rate of achievement of two out of three outcomes, and according to each outcome composing the trifecta separately.
- To evaluate postoperative recovery, including pain scores, time to first walk, time to first flatus, total use of pain medication, and readiness for discharge.
- To compare the rates and severity of postoperative complications within 30 days after surgery.
- To assess surgical parameters such as total operative time, ischemia time, and blood loss.
- To analyze functional outcomes, such as kidney function recovery (Δ eGFR at 30 days).
Study Design This is a prospective, single-center, randomized controlled trial conducted at the Department of Urology, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy.
Eligible participants will be randomly assigned 1:1 to one of two groups:
Group A (Control): Standard flank approach (transperitoneal or retroperitoneal) using the Da Vinci SP system. Patients are positioned laterally (on their side) with the operative flank elevated at a 12-15° angle. The Da Vinci SP robotic system is docked either transperitoneally or retroperitoneally through a single access port. The tumor is resected and kidney reconstruction is performed according to standard RAPN procedures Group B (Experimental): Supine anterior retroperitoneal approach (SARA) using the Da Vinci SP system. Patients are positioned supine with a mild Trendelenburg tilt (0°-10°). A retroperitoneal space is created through an anterior incision, providing direct access to the kidney without repositioning. The same Da Vinci SP system and standard nephron-sparing techniques are used.
Both groups follow identical perioperative protocols for anesthesia, analgesia, and postoperative care.
Population Adults (age 18 or older) with a single kidney tumor measuring up to 7 cm, who are eligible for robotic partial nephrectomy with the Da Vinci SP system, may be invited to participate. Patients with kidney tumor more than 7 cm or advanced tumors infiltrating the surroinding tissues, solitary kidneys, previous kidney surgery on the same kidney, or severe kidney disease will not be eligible.
Eligibility
- Age ≥ 18 years;
- Presence of a single, unilateral, primary renal mass ≤ 7 cm in diameter (clinical stage cT1) documented CT scan
- No evidence of systemic disease or lymph node involvement;
- Candidate for robot-assisted partial nephrectomy using the Da Vinci SP platform;
- Signed informed consent
- Absence of solitary kidney status
- No previous partial nephrectomy/ies on the same kidney
- Absence of preoperative chronic kidney disease (CKD) stage 5
- Absence of any condition that makes mandatory or significantly more adequate the choice of a specific approach over the others (e.g., multiple previous major abdominal surgeries, horseshoe kidney, presence of stomas)