Neurosurgeon University of Miami Miami, Florida, United States
Disclosure(s):
Michael Ivan, MD: Astra zeneca: Speaker/Honoraria (Ongoing); Invenio: Consultant (Ongoing); Medtronic: Consultant (Ongoing), Research Grant (Ongoing); Omniscient neurotechnology: Consultant (Ongoing)
Introduction: Currently, Laser interstitial thermal therapy(LITT) is limited to lesions of ~2cm sphere along a linear trajectory, requiring multiple probe placements to treat lesions shaped irregularly or larger in size. We present the development of a steerable guide for the Visualase system that enables deployment of the laser fiber along a controlled curved trajectory with micro-adjustability to further enhance its dexterity and treat lesions up to 5cm in diameter.
Methods: The steerable guide system consists of three major components: (a)Steerable stylet, (b)Visualase catheter guide and (c)Rigid cannula. It has three degrees-of-freedom, which are the rotation, curvature, and the insertion depth of the straight and curved sections, respectively. Experiments were performed by inserting the stylet into a tissue-mimicking gelatin phantom along various predefined curvature trajectories. The curvature controlling knob value was tested from 0˚ to 240˚ with an increment of 10˚. A maximum tip displacement of 25mm was achieved, which translates to a workspace of 5cm in diameter
Results: Catheter insertion experiments were performed in tissue-mimicking gelatin phantoms to investigate the safety of the system and verify the accuracy of the mathematical trajectory prediction model. Over 50 trajectory depths and angles were tested to generate a mathematical model to predict the needle tip position(xtip) and catheter curvature trajectory. This model was then validated using 50 placements and the average and standard deviation of tip position error between predicted and actual needle tip position was 0.70mm and 0.43mm respectively.
Conclusion : In this abstract, we have presented a novel steerable guide for the Visualase MRI-guided LITT system. The system was able to successfully deploy the catheter along a curved trajectory without causing tissue damage and was able to achieve variable curvatures predicted by a validated mathematical. As such, the proposed device would greatly minimize the invasiveness, operation time, cost and ultimately the efficacy of LITT.
