Anticipation of vertebral pedicle breach through dynamic surgical guidance

Abstract

OBJECTIVE: To determine the effectiveness of a pedicle probe to anticipate an impending breach and allow redirection during placement of a pilot pedicle hole. METHODS: Purposely four cortical wall sites were drilled: medial and lateral pedicle wall, and lateral and anterior wall of the vertebral body. The surgeon stopped probing when the sound changed, suggesting abutment against the cortical wall ("anticipation" of impending breach). A fluoroscopy image was then obtained. The surgeon then advanced the PediGuard through the cortex until the sound changed, indicating a breach. In the second part of the study three probes were used: 1) DSG (PediGuard) with curved tip with electronics ON; 2) DSG with electronics OFF; 3) standard Lenke probe. After the images were taken, the operating surgeon (blinded to x-rays) was instructed to redirect and continue drilling into the vertebral body. RESULTS: The surgeon accurately anticipated 60 of 75 (80%) of the breaches, 17 of 19 (89%) in the medial pedicle wall. In the second part of the study the DSG with electronics ON was superior to the DSG with electronics OFF as well as the standard Lenke probe (100% vs. 90% vs. 79%, p = 0.0191). CONCLUSION: Successful redirection by passing the pedicle probes into the vertebral body without a breach after anticipation of an impending pedicle wall breach occurred in 100% of the drillings when done with the DSG with the electronics ON vs only 84% when there was no electronic feedback.

Spine Surgery with Electronic Conductivity Device: A Prospectively Multicenter Randomized Clinical Trial and Literature Review

“…did preliminary researches on cadavers on cervical and thoracic spine. Williams et al 29 . also did a cadaver study and found that the sensitivity to detecting cortical breach was 97% in pedicle drillings and 84% in vertebral body drillings, respectively.…”

Direct Pedicle Screw Insertion Pullout Strength

“…Since the initial report on the use of pedicle screw for spine fixation, there has been a permanent improvement of this modality of spinal fixation, that is widely used to treat fractures, degenerative disease, tumor, deformities and spinal stability. ( 6 )-( 9 Pedicle screws continue to be studied to improve its locking mechanism in fixation system components, biomechanical screw performance and screw accuracy. ( 10 …”

“…( 3 )-( 5 The ability of Dynamic Surgical Guidance-DSG (PediGuard ®probe) to improve pedicle screw accuracy and to reduce radiation exposure has been shown in vitro using human cadaver specimens as well as in clinical trials. ( 6 …”

Does the Use of Dynamic Surgical Guidance Assist Accurate Pedicle Screw Placement in Patients With Osteoporosis or Osteopenia?

“…The role of the DSG device in improving pedicle screw accuracy and reducing intraoperative radiation has been observed in experimental and clinical studies, but none of them were performed in osteopenic or osteoporotic bones. [8][9][10][11][12] Although there are several technologies that assist with pedicle navigation, the DSG device is the only hand-held device that can detect possible vertebral cortex perforation during pedicle preparation for screw placement. The probe of the DSG device emits an electrical current which flows from the inner electrode to the outer electrode, creating a circular electromagnetic detection field at the tip of the instrument.…”

“…[8][9][10] The ability of Dynamic Surgical Guidance-DSG (PediGuard® probe) to improve pedicle screw accuracy and reduce radiation exposure has been shown in vitro using human cadaver specimens, as well as in clinical trials. [11][12][13] However, bone mineral density was not considered in these studies. Experimental studies have suggested that bone electrical and dielectric properties depend on the bone density.…”