Ultrasound-guided renal access and balloon dilation for PCNL in the prone position: results of a multicenter prospective observational study

Precision in Access: The Laser Direct Alignment Radiation Reduction Technique Versus Conventional Fluoroscopic Renal Access

Introduction and Objective: The laser direct alignment radiation reduction technique (DARRT) presents a novel approach integrating pulsed low-dose fluoroscopy, ultrasound, direct endoscopic visualization, and laser targeting to minimize fluoroscopy exposure during percutaneous nephrolithotomy (PCNL). This study aims to evaluate the safety and efficacy of laser DARRT in comparison with traditional fluoroscopic PCNL access. Methods: A retrospective analysis was conducted on patients who underwent PCNL. Patients with pre-existing nephrostomy tubes for access and those who underwent solely ultrasound-guided access were excluded from the study. The primary outcomes of the study were comparing fluoroscopy time used for renal access and total fluoroscopy time between the two groups. Secondary outcomes included relative stone-free rates (SFR) defined as ≤4 mm fragments on postoperative computed tomography scan and complication rates. Continuous variables were compared using an independent-sample t test, whereas categorical variables were compared using the chi-square test, with significance set at p < 0.05. Results: A total of 292 patients were eligible for the study. The laser DARRT reduced both access fluoroscopy time (10.8 vs 551.7 seconds; p < 0.001) and total fluoroscopy time (21.8 vs 597.7 seconds; p < 0.001). The relative SFR was significantly higher in the laser DARRT group compared with the conventional group (84.1% vs 64.1%; p < 0.001). There was no significant difference in complication rates between the two groups (p > 0.05). Conclusions: The laser DARRT led to a >95% reduction in access and total fluoroscopy times. By combining the advantages of fluoroscopy, ultrasound, endoscopic vision, and laser guidance, this technique represents a promising option for improving outcomes and minimizing radiation-related risk.

Percutaneous nephrolithotomy guided by 5G-powered robot-assisted teleultrasound diagnosis system: first clinical experience with a novel tele-assistance approach (IDEAL stage 1)

BACKGROUND

To demonstrate the technical feasibility of percutaneous nephrolithotomy (PCNL) guided by 5G-powered robot-assisted teleultrasound diagnosis system (RTDS) in a complex kidney-stone (CKS) cohort and present our preliminary outcomes. PCNL is highly skill-required, which hinders it popularization in primary medical units of remote regions. We designed an innovative tele-assistance approach to make PCNL easy to be operated by inexperienced surgeons.

METHODS

This was a prospective proof-of-concept study (IDEAL phase 1) on intraoperative tele-assistance provided by online urological experts via a 5G-powered RTDS. Total 15 CKS patients accepted this technology. Online experts manipulated a simulated probe to assist unskilled local operators by driving a patient-side robot-probe to guide and monitor the steps of access establishment and finding residual stones.

RESULTS

Median total delay was 177ms despite one-way network-connecting distance > 5,800 km. No perceptible delay of audio-visual communication, driving robot-arm or dynamic ultrasound images was fed back. Successful tele-assistance was obtained in all cases. The first-puncture access-success rate was 78.6% with a one-session SF rate of 71.3% and without complications of grade III-V.

CONCLUSIONS

The current technology based on 5G-powered RTDS can provide high-quality intraoperative tele-assistance, which has preliminarily shown satisfactory outcomes and reliable safety. It will break down a personal competence-based barrier to endow PCNL with more popular utilization.

TRIAL REGISTRATION

The study was approved by ethics committee of the Xinjiang Kezhou People's Hospital and ethics committee of the First Affiliated Hospital of Nanjing Medical University and was registered on http://www.chictr.org.cn (ChiCTR2200065849, 16/11/2022).

Ultrasound-guided percutaneous nephrolithotomy (PCNL) success rates in patients with elevated body mass index: a comparative study

Percutaneous nephrolithotomy (PCNL) is considered gold standard treatment of renal stones larger than 20 mm. Several studies have shown that ultrasound guidance during this procedure is more effective and safer than fluoroscopy. A higher body mass index (BMI) can make ultrasound-guided renal access more difficult and unsuccessful. We present a prospective analysis and comparison of ultrasound-guided PCNL in patients with normal and increased body mass index. We performed a prospective comparison of patients who underwent ultrasound-guided PCNL to remove renal stones by a single surgeon between 2020 and 2022. Patients with BMIs greater than 30 (mean 33.87-obese) were compared to those with BMIs less than 30 (mean 25.69-non-obese). Demographic, perioperative, and follow-up data were collected, analyzed, and included in this study. Total of 98 consecutive patients, with 49 patients in each group were analyzed. No statistically significant differences were observed in terms of stone volume (P = 0.085), stone density (P = 0.5590), location of renal access (P = 0.108), surgery duration (P = 0.38), blood loss (P = 0.54), or laboratory changes after surgery (P = 0.60). 87.76% of obese patients were stone free per CT scan at follow-up, compared to 73.47% of normal-weight patients (P = 0.1238). According to Clavien-Dindo classification, six patients in the non-obese group experienced grade II (10%) and grade III (2%) complications, as opposed to six patients in the obese group with grade I (2%), grade II (6%), and grade III (2%) complications. There was no significant correlation between body mass index and the success or safety of ultrasound-guided PCNL. Although more challenging, a higher BMI should not be an impediment to performing this approach. This method is safe, with no increased incidence of postoperative complications or compromise in stone-free status postoperatively and can diminish or avoid both patient's and medical team's exposure to ionizing radiation.

Ultrasound-Guided PCNL - Why Are We Still Performing Exclusively Fluoroscopic Access?

PURPOSE OF REVIEW

While urologists are traditionally taught to perform percutaneous nephrolithotomy (PCNL) utilizing exclusively fluoroscopy, ultrasound has emerged as a safe alternative. This article showcases the major reasons why ultrasound-guided access should be considered the first-line approach for performing access for PCNL.

RECENT FINDINGS

There continues to be a need to further reduce radiation exposure in the management of kidney stone patients. This review showcases how performing ultrasound-guided PCNL has been associated with a shorter learning curve, increased patient safety, and the ability to perform x-ray free PCNL. Ultrasound-guided PCNL is not only an achievable skill for urologists to learn but provides multiple advantages over traditional fluoroscopic access. As every effort should be given to help reduce radiation exposure for kidney stone patients as well as performing surgeons and operating theater personnel, endourologists should strive to add this technique to their armamentarium.