Objectives: This study aims to determine if the device provides an advantage over traditional free hand puncture by comparing the number of attempts required to obtain access, time to achieve access, radiation exposure to patient and surgeon; and complications.

This is a single centre, participant randomized, open label study to evaluate the efficacy and safety of automated needle targeting (ANT-X) system compared to traditional free hand puncture for achieving renal access in Percutaneous lithotomy (PCNL) performed by urologists in training.

Prior to performing kidney puncture on patients, all participating surgeons will undergo a simulation using Medical Simulation 12 balls phantom device with and without use of the ANT-X. Four urologic trainees (with similar little previous PCNL experience) will be recruited for the simulation. Two end points will be assessed: Number of attempts to achieve desired renal puncture and total fluoroscopy time.

This simulation via 12 balls phantom device will involve fluoroscopic screening of calyx and successful puncture by urologic trainees under consultant supervision. Trainees will have 30 attempts of free hand puncture and 30 attempts using the ANT-X. The trainee will only move on to patient's renal puncture once they are able to achieve more than 80% of satisfactory renal puncture on simulator.

For human renal puncture, we will aim for 60 cases of PCNL, 30 to be done using ANT-X puncture and 30 using traditional free hand puncture performed by 4 urologic trainees (15 cases per urologic trainee).

Inclusion Criteria:

• Subjects willing to sign informed consent form before initiation of any study specific procedures.
• Subjects diagnosed with kidney stones and planned for prone PCNL.
• Male/ non- pregnant female subjects between 18-75 years (both inclusive) of age at the time of informed consent.
• Subjects with renal stones of ≥1 cm or not managed by other stone treatments (e.g. shock wave lithotripsy, ureteroscopy).
• Serum creatinine of < 1.2 mg/dl.

Exclusion Criteria:

• Subjects with bleeding disorders.
• Recent infection of the kidney or urinary tract which leads to pus accumulation in the kidney, i.e., Pyonephrosis.
• Subjects not able to have prone positions for surgical procedure due to comorbid conditions.
• Renal stones < 1 cm and can managed by another technique.
• Patients with moderate to severe renal failure.
• Patients with congenital urinary tract anomalies.
• Patients on anticoagulation or antiplatelet therapy.
• Evidence or history of any other disease that in the opinion of the investigator would put the patient at risk through study participation, or would affect the study analyses if the disease exacerbated during the study.
• Legal incapacity or other circumstances that render the subject unable to understand the nature, scope and possible consequences of the study.
• Clinically significant abnormal findings or condition (other than kidney stone), which might, in the opinion of the Investigator, interfere with study evaluations or pose a risk to subject safety during the study.