Robotic ultrasound-guided prostate intervention device: system description and results from phantom studies.

BACKGROUND: We introduce the first robotic ultrasound-guided prostate intervention device and evaluate its safety, accuracy and repeatability. METHODS: The robotic positioning system (RPS) determines a target's x, y and z axes. It is situated with a biplane ultrasound probe on a mobile horizontal platform. The integrated software acquires ultrasound images for three-dimensional (3D) modelling, coordinates target planning and directs the RPS. RESULTS: The egg phantom evaluates the software's safety and workflow protocol. Two random targets are planned in each quadrant and biopsy needles are inserted. All were within three separate eggs. Metal wire tips are targeted and their distances from the biopsy needle tips are measured. With 20 wires, < 1 mm accuracy is obtained. Repeatability is demonstrated when previous positions are returned to with similar accuracy. CONCLUSION: Our device demonstrates safety in a defined boundary with a repeatable accuracy of < 1 mm. It can be used for accurate prostate biopsy and treatment delivery.

A rare life-threatening complication of migrated nitinol self-expanding metallic stent (Ultraflex).

The use of self-expanding metallic stents (SEMS) as esophageal endoprosthesis represents an advancement in the palliation of dysphagia from unresectable esophageal carcinoma. However, the problem of stent migration persists. Although most migrated stents have a benign outcome, complications do occur. Rare reports of intestinal obstruction have been confined to the stiff plastic and stainless-steel stents. We report the first case of intestinal obstruction secondary to the pliable Nitinol SEMS (Ultraflex) migration.