Intraosseous ultrasonography to determine the accuracy of drill hole positioning prior to the placement of pedicle screws: an experimental study

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Dorsal fixation with rods and pedicle screws (PSs) is the most frequently used surgery to correct traumatic and degenerative instabilities of the human spine. Prior to screw placement, screw holes are drilled along the vertebral pedicles. Despite the use of a variety of techniques, misplacement of screw holes, and consequently of the PSs, is a common problem. The authors investigated the usefulness of an intraspinal, intraosseous ultrasonography technique to determine the accuracy of drill hole positioning.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>An endovascular ultrasound transducer was used for the intraluminal scanning of bore holes in trabecular bovine bone, 12 pedicle drill holes in cadaveric human spine, and 4 pedicle drill holes in a patient undergoing thoracic spondylodesis. Seven of the experimental bore holes in the cadaveric spine were placed optimally (that is, inside the pedicle) and 5 were placed suboptimally (breaching the medial or lateral cortical surface of the pedicle). Computed tomography scans were obtained in the patient and cadaveric specimen after the procedure.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>The image quality achieved in examinations of native bovine bone tissue, the formalin-fixed human spine specimen, and human vertebrae in vivo was equal. The authors endosonographically identified correct intrapedicular and intravertebral positions as well as poor (cortex breached) placement of drill holes.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Intraosseous ultrasonography is a promising technique for the investigation of PS holes prior to screw implantation, and may add to the safety of PS placement.</jats:p></jats:sec>

Imaging Capability at Close Range of High Frequency Ultrasound Transducer on the Perforation of Bony Walls Simulating Pedicle Screw Placement

“…But it is well known that the higher frequency can get higher image quality(high resolution), shorter near-field region and smaller transducer size [15]. In selected cases, it could even visualize fissure-like fractures in cadaveric bone [10]. Theoretically the resolution of our new-fabricated 30MHz transducer in this study can be increased by 50% and the size decreased by about 50% compared with 20MHz counterpart [16].…”

“…Kantelhardt et al [10] reported that the smallest diameter of the breach identified by intraosseousultrasonography was 4mm by 20MHz intravascular ultrasound transducer. In this study, we were able to detect a 2mm-sized hole at the distance of 1mm from the bone surface, which met the clinical need for pedicle perforation detection effectively.…”

“…Due to the advantages of real-time imaging, free of ionizing radiation and portability, some attempts in developing ultrasound-assisted pedicle screw placement have been reported [5], [9][10][11][12][13] and demonstrated promising potential. Mujagi´ et al [14] investigated the acoustic properties of human vertebral cancellous bone specimens using low frequency transducers (1MHz and 3.5MHz).…”

“…Although the above-mentioned low frequency ultrasound beam can penetrate into the trabecular bone and imaging the surrounding cortical wall, the inner surface of the bore holes cannot be visualized. In view of the high resolution in the imaging of intravascular lesions, Kantelhardt et al [9,10] firstly reported the intrapedicular imaging using 20MHz intravascular ultrasound (IVUS) transducer. At the site of experimental pedicle perforation, ultrasonography showed a focal loss of the circular shape of the highly echoic bone interface, which suggested high frequency transducer had the potential to detect the breach and corresponding site in the walls of bore hole during pedicle screw placement procedure.…”

Feasibility of Endoscopic Inspection of Pedicle Wall Integrity in a Live Surgery Model

“…1 Other pressure-and electrical conduction-based techniques to verify pedicle accuracy, such as specialized piezoelectric piercer probes, can also lead to misplaced pedicle screws 31 and can result in false-negative errors. 32,33 Other emerging techniques such as intraosseous ultrasound, [34][35][36][37][38][39] robotic guidance, or near-infrared spectroscopy, require substantial equipment and are not without false-negative errors. 40,41 To our knowledge, our study is the first to report successful endoscopic visualization of the internal aspect of a lumbar pedicle with low-flow irrigation.…”