Application of the ISYS1 robotic device for stereotactic neurosurgical interventions: a preclinical phantom trial

Submillimetric precision is essential for stereotactic neurosurgical procedures. However, accuracy of standard neuro-surgical procedures such as navigated biopsies and shunts is currently limited due to manual alignment of the biopsy needle or manual placement of the shunt catheter. The aim of this study is to evaluate the feasibility and accuracy of a novel robotic positioning device for stereotactic neurosurgical procedures. We conducted a preclinical phantom trial to evaluate the accuracy of the iSYS1 ® robotic device in a representative stereotactic neurosurgical procedure: Robotic guidance of a biopsy needle was compared to standard manual needle trajectory alignment. Biopsies were performed by 7 neurosurgeons of different levels of experience either with robotic trajectory alignment (n=81) or manual alignment using a standard mechanical biopsy arm (n=81) under navigational guidance (Medtronic StealthStation S7 ®). The paper describes the setup, the test methodology as well as the achieved results. 1 Introduction Operations involving positioning of needles and catheters are amongst the most common procedures in cranial neuro-surgery. However, submillimetric precision is essential for the success of most neurosurgical procedures. Although some neurosurgical procedures are performed using a skull-mounted stereotactic frame for high precision (cf electrode placement for deep brain stimulation), this setup is costly and time-consuming. Therefore, many procedures that involve placement of a catheter for fluid drainage or a needle for obtaining tissue specimens are currently performed with limited accuracy, i.e. using a mechanical arm or even free-hand. This could potentially lead to procedural failure such as malpositioning of a catheter, inconclusive tissue sampling and even major complications, e.g. cerebral hemorrhage with consecutive neurologic morbidity. Therefore, navigation-guidance was implemented and established over the last two decades 1-12. Using preoperatively compiled anatomical patient data from radiological images (Computerized Tomography [CT] or Magnetic Resonance Imaging [MRI] scans) a trajectory from entry to target point can be defined and matched intraoperatively on the pa-tient's head. Alignment of the needle or catheter with the preplanned trajectory is then performed either freehand (shunt catheter placement) or using a mechanical stereotactic arm (needle biopsy). This, however, is associated with major drawbacks due to inaccuracy of the freehand trajectory adjustment method. Up to 40% of all shunts fail in the first year 13, 14 , most commonly due to proximal obstruction with ingrowth of choroid plexus or gliosis around the catheter 15, 16 based on a misplacement of the catheter tip. Each malfunction carries the risk of additional morbidity and could …