- Professor of Neurosurgery, University of Nebraska Medical Center, Omaha, NE, USA
DOI:10.4103/2152-7806.63912© 2010 Patil AA This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
How to cite this article: Patil AA. Computed tomography-guided vertebroplasty using a stereotactic guidance system (stereo-guide). Surg Neurol Int 31-May-2010;1:17
How to cite this URL: Patil AA. Computed tomography-guided vertebroplasty using a stereotactic guidance system (stereo-guide). Surg Neurol Int 31-May-2010;1:17. Available from: http://sni.wpengine.com/surgicalint_articles/computed-tomography-guided-vertebroplasty-using-a-stereotactic-guidance-system-stereo-guide-2/
BackgroundIn order to make it easy to perform computed tomography (CT)-guided vertebroplasty a stereotactic guidance system called the "stereo-guide" was designed. A method to perform CT-guided vertebroplasty using this system is described.
MethodsThe device is a rectangular flat plastic block. One of the flat surfaces of the block has deeply grooved protractor markings at 5-degree intervals; ranging from 0 to 30 degrees. The procedure is performed on the CT table. Based on distances and angle measurements obtained from CT images the device is placed on an appropriate location on the back of the patient and the needle is advanced to the target through the pedicle guided by the grooves on the device. Ten procedures were performed in nine patients with lumbar and thoracic pathology.
ResultsThe system was easy to use and proved to be accurate. No complication resulted from the procedure.
ConclusionThe stereo-guide proved to be simple and easy to use. Intraoperative scans helped to plan the trajectory and follow the injection of the cement.
Keywords: Computed tomography guidance, stereotactic, vertebral fracture, vertebroplasty
Vertebroplasty is a common procedure for compression fractures of vertebral bodies associated with pain.[
Description of the device
The device [
The patient was placed prone on the CT table under general anesthesia. The table height was adjusted so as to place the patient approximately at the isocenter of the gantry. This was necessary in order to obtain scans with a tilt in the gantry. A lateral scout image was obtained. The angle of the pedicles with the vertical was measured. The gantry was tilted to this angle. Serial CT scans were obtained in the area of interest with a scan thickness and interval of 2 millimeters. The number of scans through the pedicle was counted and the middle one was chosen for distance measurements [
A sketch of the stereotactic guide positioned on CT axial image obtained during needle insertion. A-the target point; CB-distance from the midline to entry point of the needle on the skin surface; BD-distance from the skin surface to the top of the pedicle; BA- the distance of the trajectory from the skin surface to the target; and angle at A-angle of the trajectory with the vertical; white arrow-trajectory of the needle; black arrow shows the needle positioned in the appropriate groove in the stereo-guide. Note that the stereo-guide is held perfectly horizontal in the coronal plane
Ten procedures were performed on nine patients without any complication and good relief of pain in all. All procedures were done through one pedicle. The male/female ratio was 3/6 and age range was 50-70 years. The follow-up is between 7-31 months with a median of 26 months. One patient had two procedures at two different times (one at L2 and another at T10). Six procedures were at L1; two at L2; and one each at L3 and T10.
This is a simple device with straightforward methodology. In our small experience it was found to be useful. Since it is handheld it can introduce errors. However, because intraoperative scans are obtained these errors are corrected to get accurate placement of the needle. Furthermore, the procedures were done under general anesthesia to prevent patient movement. The system could be improved by having a rigid system to hold it in place; and by having a rigid probe holder.
Though fluoroscopic images offer a straightforward technique, the distinct advantage of CT images is that they provide images in the axial, coronal and sagittal planes. In addition, we were able to have entry to the target through only one pedicle; because it is easy to plan a trajectory to a target close to the middle of the vertebral body using this device.
There may be concern about how quickly one can obtain scans while following the entry of the cement into the vertebral body. Fortunately, most modern scanners are very fast and have a viewing screen in the scanner room. It is, therefore, possible to obtain a successive series of scans and observe the flow of the cement in the scanner room during injection. In addition, one can also use the CT-fluoroscopic mode.
Most CT scanners can display images in all three planes almost immediately after the scans are obtained. Therefore, display of the needle in all three planes as it is being advanced to the target makes this system particularly useful for patients who have severe compression fractures. Similarly, it also makes it easy to follow the flow of the cement in all three planes, especially when there is concern of flow of cement into the spinal canal in patients who have minimal retropulsion of fractured segment.
In summary, a simple device and methodology for CT-guided vertebroplasty is described. Use of intraoperative CT scans made this procedure accurate. Furthermore, axial CT images enabled us to perform the procedure through a single pedicle.
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