Electromagnetic tracking of flexible robotic catheters enables "assisted navigation" and brings automation to endovascular navigation in an in vitro study.

OBJECTIVE: Combining three-dimensional (3D) catheter control with electromagnetic (EM) tracking-based navigation significantly reduced fluoroscopy time and improved robotic catheter movement quality in a previous in vitro pilot study. The aim of this study was to expound on previous results and to expand the value of EM tracking with a novel feature, assistednavigation, allowing automatic catheter orientation and semiautomatic vessel cannulation. METHODS: Eighteen users navigated a robotic catheter in an aortic aneurysm phantom using an EM guidewire and a modified 9F robotic catheter with EM sensors at the tip of both leader and sheath. All users cannulated two targets, the left renal artery and posterior gate, using four visualization modes: (1) Standard fluoroscopy (control). (2) 2D biplane fluoroscopy showing real-time virtual catheter localization and orientation from EM tracking. (3) 2D biplane fluoroscopy with novel EM assisted navigation allowing the user to define the target vessel. The robotic catheter orients itself automatically toward the target; the user then only needs to advance the guidewire following this predefined optimized path to catheterize the vessel. Then, while advancing the catheter over the wire, the assisted navigation automatically modifies catheter bending and rotation in order to ensure smooth progression, avoiding loss of wire access. (4) Virtual 3D representation of the phantom showing real-time virtual catheter localization and orientation. Standard fluoroscopy was always available; cannulation and fluoroscopy times were noted for every mode and target cannulation. Quality of catheter movement was assessed by measuring the number of submovements of the catheter using the 3D coordinates of the EM sensors. A t-test was used to compare the standard fluoroscopy mode against EM tracking modes. RESULTS: EM tracking significantly reduced the mean fluoroscopy time (P < .001) and the number of submovements (P < .02) for both cannulation tasks. For the posterior gate, mean cannulation time was also significantly reduced when using EM tracking (P < .001). The use of novel EM assisted navigation feature (mode 3) showed further reduced cannulation time for the posterior gate (P = .002) and improved quality of catheter movement for the left renal artery cannulation (P = .021). CONCLUSIONS: These results confirmed the findings of a prior study that highlighted the value of combining 3D robotic catheter control and 3D navigation to improve safety and efficiency of endovascular procedures. The novel EM assisted navigation feature augments the robotic master/slave concept with automated catheter orientation toward the target and shows promising results in reducing procedure time and improving catheter motion quality.

Pyoderma gangrenosum with an underlying ulcerative colitis associated with bone tuberculosis.

Pyoderma gangrenosum is a rare noninfective neutrophilic dermatosis, characterized by progressive painful ulceration. It is frequently associated with systemic disorders like inflammatory bowel disease, rheumatoid arthritis and myeloproliferative diseases. However, its association with infectious diseases in particular with tuberculosis is extremely rare. Diagnosis is based on the history of an underlying disease, a typical clinical presentation, histopathology and exclusion of other diseases leading to ulcerations of similar appearance. Immunosuppression with corticosteroids remains the mainstay of treatment. We report a case of a 49-year-old male with long-standing ulcerative colitis, associated with tuberculosis of hip, who presented with nonhealing ulcers over the lower extremity.

Zosteriform skin metastases: clue to an undiagnosed breast cancer.

Cancer metastases represent the most devastating aspect of malignancy, since the mortality of cancer patients is mainly related to the metastatic behavior of the primary neoplasm. Skin metastases are usually late events in the course of tumor progression. Excluding melanoma, the most common tumor to metastasize to the skin is breast cancer. Patients who develop cutaneous metastases rarely present with a zosteriform distribution. Herein, we present a 60-year-old female, an undiagnosed case of breast cancer, with zosteriform metastases along her right T2-T3 dermatome.