1 Facilitation of Dynamic Flexion & Extension of the Neck During Fluoroscopy Team Members Alison Boumeester Kaitlin Brendel Megan Britson Allie Finney Peter Strohm Advisor Walter Block, Ph.D. Department of Biomedical Engineering Clients Victor Haughton, M.D. UW Department of Radiology Josh Medow, M.D. UW Department of Neurological Surgery December 12th, 20072 Table of Contents Abstract……………………………………………………………………………………….………………………….….………3 Motivation………………………………………………………………………………………………………………….……….3 Background Information……………………………………………………………………….…………………….……...4 Design Requirements………………………………..……………………………………………………………….………..7 Alternative Designs……………………………………………………………………………………………………………..8 Final Design and Prototype…………………………….………………………….……………………………………...12 Future Work………………………………………..…………………………………….……………………………………...14 Appendix…………………………………………………..………………………………………………..………………..……16 Budget…………………………………………………………………………………………………………………………..…..19 Project Design Specifications…………………………………………………………………………………..…………20 References…………………………………………………………………………………………………….………………….223 Abstract A device is needed to replace existing methods of extending and flexing an obtunded patient’s neck during fluoroscopic examination of the cervical spine. A previous design achieved a full range of motion, but was cumbersome and difficult to attach because it hung off the end of the table. This semester’s prototype includes a gear and motor system that is more ergonomic with strong consideration of patient safety. Motivation Patients with cervical spine injuries that are brought into the hospital are often imaged to determine the severity of their injuries, especially if the patient is obtunded and unable to provide feedback about his or her pain. If the injury occurred less than 72 hours prior to the time of imaging, an MRI scan can be preformed to diagnose spinal health. However, once 72 hours has passed, a healthy spine cannot be distinguished from an injured spine with an MRI. At that time, fluoroscopic imaging can be used (Medow, 2007). Fluoroscopic imaging allows for observation of movement and interaction of the vertebrae during neck motion. Detected abnormalities in movement may indicate injury. Currently, the hospital staff manually flexes and extends the neck during imaging (Medow, 2007). This unnecessarily exposes the staff to radiation. Also, this method lacks precision and repeatability. A safe and reliable device is needed that will flex and extend the patient's neck at a consistent rate.4 Background Information Cervical Spine The cervical spine is anatomically defined as the first seven vertebrae of the spinal column, starting at the base of the skull. Compared to the thoracic or lumbar vertebrae, the cervical vertebrae are smaller in size. The cervical vertebrae serve as an anchor for muscles, tendons, and ligaments that facilitate movement of the head and neck. The neck is capable of a wide variety of motions, including lateral isocentric rotation, abduction and adduction, and extension and flexion (Saladin, 2007). Extension of the neck occurs when the angle between the chin and chest is increased (the head is leaned back, shown in Figure 1), and flexion occurs as the chin- chest angle decreases (the head is brought forward, as seen in Figure 1). Nerve tracts to vital organs and skeletal muscle pass through these first seven vertebrae. Damage to any of the nerve pairs or the spinal cord itself is a serious health concern. Lesions or severance can lead to permanent paralysis of part or all of the body, depending on the site of damage (Saladin, 2007). Victims of traumatic events, especially vehicle or motorcycle accidents, have their cervical spine immobilized by a protective collar to minimize the risk of aggravating an injury before they are diagnosed at a hospital. These patients may be conscious, but frequently they are obtunded and unable to communicate with medical staff about pain they may be experiencing. Even patients claiming no pain are still treated as if they may have fractured vertebrae, damaged ligament or disc, or even a direct injury to the spinal cord. Imaging the neck has become a routine procedure for patients at risk for cervical spine trauma. Analyzing the image data assists doctors in assessing the stability and health of Figure 1 www.wheelesonline.com5 the cervical spine before deciding whether or not the patient should remain immobilized in the neck collar (Medow, 2007). Fluoroscopic Imaging Fluoroscopy is just one of several tools used by medical professionals for imaging internal structures of the body. By taking a rapid sequence of x-ray images and immediately displaying them as they are processed, fluoroscopy provides medical staff with the ability to “see” in real time the dynamic behavior different tissues. To take the image, a focus beam of x-rays is passed through the ends of a c-arm oriented such that the ends face the region of interest (Figure 2) (Medow, 2007). This provides the unique opportunity to observe the actual motion of tissues instead of a static image, as given by MRI or standard radiographs. The time of fluoroscopic procedures is kept to a minimum to reduce the exposure of the patient to radiation from the x-rays. By using dynamic fluoroscopic imaging, injuries that otherwise would have been missed by the static imaging can be detected. This is not to say that fluoroscopic imaging should be the lone method of imaging. It is common practice for several types of imaging to be used to ensure that
View Full Document
Unlocking...