Handheld Concentric Tube Robot for Percutaneous Nephrolithotomy

The field of continuum robotics continues to advance rapidly, giving these manipulators potential to change the paradigm of minimally invasive medical surgery (MIS) in a near future. As MIS techniques are refined to improve recovery and cosmesis and reduce invasiveness and co-morbidity, continuum robot requirements in MIS applications have become ever stricter. One such application is Percutaneous Nephrolithotomy (PCNL), a first-choice minimally invasive urological procedure for the extraction of large renal calculi (kidney stones) > 2 cm. The standard of care in PCNL entails the percutaneous insertion of a nephroscope via a small incision in the lumbar or lateral abdominal wall regions, followed by accessing a renal calyx to allow direct manipulation of the stone using specialized lithotripsy devices such as ultrasonic or laser equipment, which aids in reducing blood loss during survery [1]. This study proposes a lightweight, compact handheld Concentric Tube Robot (CTR) as an alternative to the conventional straight and rigid PCNL tools. Unlike Girerd et al. [2] our design was conceived solely for the use in PCNL. Our envisaged device aims to provide an alternative to the conventional rigid nephroscopes by flexibly maneuvering the handheld CTR through a prescribed renal calyx and reaching clinical targets while safeguarding sensitive anatomical structures, as illustrated in Fig. 1. Additionally, it is designed to deliver an energy source through its lumen to the renal calculi for laser ablation.