The next step in 2/3D intraoperative x-ray imaging

The O-ARM (Medtronic) is a 2 and 3 dimensional (2D and 3D) imaging solution for spine and orthopaedic surgeons, that is, according to the company, fast, effective and produces high quality images. Surgeons can either take 2D fluoroscopic images, or obtain a 3D volumetric scan of the patient. Besides image quality, simplicity of handling is the second main advantage. All motions of the unit are motor driven and can be controlled by the touch of a button. Once ideal positions for images are found, they are stored into memory and can be recalled whenever needed during surgery leading the gantry of the unit to place itself in the exact same position as at the acquisition of the earlier image. Unlike C-arm systems, this capability can eliminate the need for additional scout shoots thereby limiting xray exposure and time loss to get back to the position. The possibility to store multiple positions eliminates the need for multiple C-arms, and allows the surgeon to ’park’ the gantry out of his way within seconds when no images are needed. Once a new acquisition is needed, by simply pushing one button, the gantry is quickly recalled to the desired imaging position. Despite size and weight of the O-ARM, the motorisation allows every staff member to handle it with one hand, and to maneuver it in the OR setting. The O-shaped gantry that holds the detector can be open to allow lateral access to the OR table, crucial to fit in the OR workflow. Once opened, the gantry can easily been draped using a custom drape, to ensure uncompromised sterility during intervention. The system utilises a 30cm x 40cm state-of-the-art digital flat panel detector with enhanced dynamic range and high spatial resolution. This ensures high image quality and a large field of view. The digital detector allows an image size approximately three times bigger then the one of a classic 9” C-arm. In addition, the square images are distortion free. A 30” flat screen on the view station allows the surgeon to have a clear view of the images. Imaging viewing can be controlled by a sterile wireless mouse from the OR-table by the surgeon, 3D image acquisition takes 13 seconds, in which the flat panel detector acquires close to 400 images in a 360 degree spin around the patient. A few second latter the surgeon is presented with a 3D volume, similar to data from computed tomography (CT), that allows the user to see the scanned volume under any angle and gives precise information to the sureon while the patient is still in the OR. In many cases, the O-ARM control scan can eliminate the need of a post operative CT. The O-ARM interfaces with Medtronic’s navigation system, greatly simplifying the navigation and reducing x-ray exposure for patient, surgeon and staff. Patients are automatically registered to the O-ARM images and surgeons are able to navigate on 3D images taken less then a minute earlier of their patient on the OR table. If an update is needed, this can easily be done by scanning again without any need to register the scan to the patient to make navigation possible. “The combination of 3D intra-operative imaging and surgical navigation with reduced radiation exposure guarantees the highest possible level of excellence in surgical treatment of complex spine patients”, says Dr Matthias Oertel, neurosurgeon, University Clinic in Giessen, Germany, and user of the first O-ARM outside the US. Optimised for skeletal imaging and thus for applications in spine- and orthopaedic surgery, the O-ARM is an ideal tool for any bone application. Its intra-operative 3D image capabilities are of special interest for more complicated or minimal invasive cases and allow the surgeon to approach these cases in a new way. It also qualifies very well for trauma applications where its large field of view and the capabilities to align to the needed view are assets. The O-ARM was developed by Breakaway Imaging, established in 2002. First units were shipped in April 2006. In June 2007, Medtronic acquired the company.