A-Mode ultrasound guidance for pedicle screw advancement in ovine vertebral bodies

Abstract

The increase in the BUB amplitudes in the distal insertion pathway suggests that, at least with a 2.5-MHz transducer, an approximate 1.5-cm US window exists in most cases, by which close approach of the ventral marrow-cortex interface could be anticipated. Other ratios may serve as stop criteria to prevent further drilling. A precipitous drop in BUB amplitude may be an indication of a cortex perforation.

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.…”

Proof of concept: In vitro measurement of correlation between radiodensity and ultrasound echo response of ovine vertebral bodies

“…After the measurement, the transducer is drawn out and the power dental burr is inserted into the cannulated screw to deepen the hole by a certain depth, e.g., 5 mm. This drilling and pulse-echo measurement procedure is repeated until either the amplitude of the measured echo signal becomes about 2.25 times larger than the smallest value or three consecutive increases in ultrasound amplitude is observed when the measurement is performed at 5 mm increments [3]. In fact, the decision criterion was made from the experiments with ovine vertebral bodies.…”

“…These complications include injury to the spinal cord or to the spinal nerve roots [1], [2]. Recently, we proposed a guidance method that could be used to reduce the incidence of these complications [3]. The method exploited the empirical finding that ultrasound amplitude changed at successive measurement sites along the insertion pathway of an ultrasound transducer—from the outer posterior cortex, through the pedicle, and toward the distal ventral cortex of the vertebral body.…”

Three‐dimensional image‐guided placement of percutaneous pedicle screws without the use of biplanar fluoroscopy or Kirschner wires: technical note

“…It should be noted that in each of these kyphoplasty studies, the measured or estimated radiation dose to the patient was well within recommended safety margins. No radiation exposure to the patient or surgeon occurs with ultrasound‐based, image‐guided systems; however, only a few in vitro studies exist describing this technique and its clinical application has yet to be determined36, 37.…”