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Minimally invasive percutaneous transpedicular screw fixation: increased accuracy and reduced radiation exposure by means of a novel electromagnetic navigation system.

von Jako R, Finn MA, Yonemura KS, Araghi A, Khoo LT, Carrino JA, Perez-Cruet M - Acta Neurochir (Wien) (2010)

Bottom Line: Greatest EMF accuracy was achieved in the lumbar spine, with significant improvements in both ideal trajectory and reduction of pedicle breaches over fluoroscopically guided placement (64.9% vs. 40%, p = 0.03, and 16.2% vs. 42.5%, p = 0.01, respectively).Time for insertion did not vary between the two techniques.Minimally invasive pedicle screw placement with the aid of EMF image guidance reduces fluoroscopy time and increases placement accuracy when compared with traditional fluoroscopic guidance while adding no additional time to the procedure.

View Article: PubMed Central - PubMed

Affiliation: GE Healthcare, Boston, MA, USA. drvonjako@comcast.net

ABSTRACT

Background: Minimally invasive percutaneous pedicle screw instrumentation methods may increase the need for intraoperative fluoroscopy, resulting in excessive radiation exposure for the patient, surgeon, and support staff. Electromagnetic field (EMF)-based navigation may aid more accurate placement of percutaneous pedicle screws while reducing fluoroscopic exposure. We compared the accuracy, time of insertion, and radiation exposure of EMF with traditional fluoroscopic percutaneous pedicle screw placement.

Methods: Minimally invasive pedicle screw placement in T8 to S1 pedicles of eight fresh-frozen human cadaveric torsos was guided with EMF or standard fluoroscopy. Set-up, insertion, and fluoroscopic times and radiation exposure and accuracy (measured with post-procedural computed tomography) were analyzed in each group.

Results: Sixty-two pedicle screws were placed under fluoroscopic guidance and 60 under EMF guidance. Ideal trajectories were achieved more frequently with EMF over all segments (62.7% vs. 40%; p = 0.01). Greatest EMF accuracy was achieved in the lumbar spine, with significant improvements in both ideal trajectory and reduction of pedicle breaches over fluoroscopically guided placement (64.9% vs. 40%, p = 0.03, and 16.2% vs. 42.5%, p = 0.01, respectively). Fluoroscopy time was reduced 77% with the use of EMF (22 s vs. 5 s per level; p < 0.0001) over all spinal segments. Radiation exposure at the hand and body was reduced 60% (p = 0.058) and 32% (p = 0.073), respectively. Time for insertion did not vary between the two techniques.

Conclusions: Minimally invasive pedicle screw placement with the aid of EMF image guidance reduces fluoroscopy time and increases placement accuracy when compared with traditional fluoroscopic guidance while adding no additional time to the procedure.

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Related in: MedlinePlus

Photograph showing how the K-wires are inserted through the Nav access needle with EMF receiver
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Fig4: Photograph showing how the K-wires are inserted through the Nav access needle with EMF receiver

Mentions: After placement of the EMF transmitter, anteroposterior (AP) and lateral fluoroscopic views of the vertebrae were saved on the Nav system. Transpedicular K-wires were then placed percutaneously using either the image guidance Nav Access needle or a standard Jamshidi needle with the aid of live AP and lateral fluoroscopic imaging (Figs. 4 and 5). The percutaneous pedicle screw systems used similar tools, which required placement over the transpedicular K-wires. In the Nav group, these were all image guided and placed using the EMF cannulated T-handle, which allowed for real-time biplanar visualization of the trajectory and progression of the instrument through the pedicle. Standard fluoroscopic technique was used in the Fluoro group. The screw extenders and K-wires were removed, leaving the screws in place for subsequent computed tomography (CT) scan evaluation of screw placement accuracy.Fig. 4


Minimally invasive percutaneous transpedicular screw fixation: increased accuracy and reduced radiation exposure by means of a novel electromagnetic navigation system.

von Jako R, Finn MA, Yonemura KS, Araghi A, Khoo LT, Carrino JA, Perez-Cruet M - Acta Neurochir (Wien) (2010)

Photograph showing how the K-wires are inserted through the Nav access needle with EMF receiver
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040822&req=5

Fig4: Photograph showing how the K-wires are inserted through the Nav access needle with EMF receiver
Mentions: After placement of the EMF transmitter, anteroposterior (AP) and lateral fluoroscopic views of the vertebrae were saved on the Nav system. Transpedicular K-wires were then placed percutaneously using either the image guidance Nav Access needle or a standard Jamshidi needle with the aid of live AP and lateral fluoroscopic imaging (Figs. 4 and 5). The percutaneous pedicle screw systems used similar tools, which required placement over the transpedicular K-wires. In the Nav group, these were all image guided and placed using the EMF cannulated T-handle, which allowed for real-time biplanar visualization of the trajectory and progression of the instrument through the pedicle. Standard fluoroscopic technique was used in the Fluoro group. The screw extenders and K-wires were removed, leaving the screws in place for subsequent computed tomography (CT) scan evaluation of screw placement accuracy.Fig. 4

Bottom Line: Greatest EMF accuracy was achieved in the lumbar spine, with significant improvements in both ideal trajectory and reduction of pedicle breaches over fluoroscopically guided placement (64.9% vs. 40%, p = 0.03, and 16.2% vs. 42.5%, p = 0.01, respectively).Time for insertion did not vary between the two techniques.Minimally invasive pedicle screw placement with the aid of EMF image guidance reduces fluoroscopy time and increases placement accuracy when compared with traditional fluoroscopic guidance while adding no additional time to the procedure.

View Article: PubMed Central - PubMed

Affiliation: GE Healthcare, Boston, MA, USA. drvonjako@comcast.net

ABSTRACT

Background: Minimally invasive percutaneous pedicle screw instrumentation methods may increase the need for intraoperative fluoroscopy, resulting in excessive radiation exposure for the patient, surgeon, and support staff. Electromagnetic field (EMF)-based navigation may aid more accurate placement of percutaneous pedicle screws while reducing fluoroscopic exposure. We compared the accuracy, time of insertion, and radiation exposure of EMF with traditional fluoroscopic percutaneous pedicle screw placement.

Methods: Minimally invasive pedicle screw placement in T8 to S1 pedicles of eight fresh-frozen human cadaveric torsos was guided with EMF or standard fluoroscopy. Set-up, insertion, and fluoroscopic times and radiation exposure and accuracy (measured with post-procedural computed tomography) were analyzed in each group.

Results: Sixty-two pedicle screws were placed under fluoroscopic guidance and 60 under EMF guidance. Ideal trajectories were achieved more frequently with EMF over all segments (62.7% vs. 40%; p = 0.01). Greatest EMF accuracy was achieved in the lumbar spine, with significant improvements in both ideal trajectory and reduction of pedicle breaches over fluoroscopically guided placement (64.9% vs. 40%, p = 0.03, and 16.2% vs. 42.5%, p = 0.01, respectively). Fluoroscopy time was reduced 77% with the use of EMF (22 s vs. 5 s per level; p < 0.0001) over all spinal segments. Radiation exposure at the hand and body was reduced 60% (p = 0.058) and 32% (p = 0.073), respectively. Time for insertion did not vary between the two techniques.

Conclusions: Minimally invasive pedicle screw placement with the aid of EMF image guidance reduces fluoroscopy time and increases placement accuracy when compared with traditional fluoroscopic guidance while adding no additional time to the procedure.

Show MeSH
Related in: MedlinePlus