Pedicle screw-based stabilization is the gold standard for treating spinal instabilities and deformities. Technological advancements such as screws in the thoracic spine, Cortical Bone Trajectory and Minimally Invasive Surgery are compounding the importance of pedicle screw placement.
Accuracy of Pedicle Screw Placement remains a Critical Issue in Spine Surgery
“The main risk associated with placing pedicle screws is pedicle perforation, which occurs when the screw exits the vertebrae. This can result in dural tears, vascular injury, nerve injury or, rarely, spinal cord injury.” (NICE 2015)1
Consequences of Misplaced Pedicle Screws are not to be Underestimated
PediGuard devices are the only handheld devices that can anticipate2 and/or detect possible vertebral cortex perforation during pedicle preparation for screw placement. PediGuard probes can alert the surgeon prior to a breach by accurately analyzing the electrical conductivity of the surrounding tissues in real time. In an European multi-centre clinical trial with 11 senior surgeons in 9 centers, 521 pedicle drillings were performed on 97 patients. The PediGuard probe detected and therefore prevented 98% of breaches (63/64)3.
Strong Results in a Wide Number of Clinical Studies Worldwide4-12
Those data suggest that accuracy of pedicle screw placement with the PediGuard device is drastically improved ranging from 94%12 to 99%13.
Accuracy Increased in Four Randomized Clinical Studies5,6,9
*There were no difference in Chaput’s study because the surgeons relied on many fluoroscopic shots to provide a safe screw placement (7.5 fluoroscopic shots (range, 2-17) in the standard group versus 5.2 (range, 0-15) per screw in the PediGuard group, P < 0.0001)).
Real Time Breach Detection and Anticipation
In a cadaver study in the U.S.2, the PediGuard probe warned the surgeons for an impending breach:
3-Fold Reduction in Neurophysiological Alarms14
Screw placement in 248 scoliosis patients was retrospectively studied, and when a PediGuard probe was used:
3 times less neuromonitoring alarms per screw were recorded,
Almost twice as many screws were inserted per patient.
Comparison of PediGuard to EMG shows an Improvement in Sensitivity and Specificity Rates
Updated Guidelines for Intra-Operative Monitoring (IOM), 2014
The American Association of Neurological Surgeons have updated their guidelines regarding IOM during lumbar fusion for degenerative spine disease15:
There is no evidence to date that IOM can prevent injury to the nerve roots.
There is limited evidence that a threshold below 5 mA from direct stimulation of the screw can indicate a medial pedicle breach by the screw.
Unfortunately, once a nerve root injury has taken place, changing the direction of the screw does not alter the outcome.
Additionally, Reviews of national databases16-17 demonstrated that the use of EMG and neuromonitoring for spine fusions does not decrease the risk of neurological injuries.
The Dynamic Surgical Guidance technology provides valuable feedback without interrupting the surgical procedure.
References
1 – NICE. Medtech innovation briefing. The PediGuard for placing pedicle screws in spinal surgery. Published: 25 March 2015
2 – Williams J. Anticipation of vertebral pedicle breach through dynamic surgical guidance. Coluna/Columna. 2014;13(3):210-3
3 – Bolger C et al. Electrical conductivity measurement: a new technique to detect iatrogenic initial pedicle perforation. Eur Spine J. 2007 Nov;16(11):1919-24
4 – Zarate. Comparison of two safety methods in the installation of pedicle screws used in minimally invasive spine surgery. SpineWeek 2023
5 – Defino H et al. Does The Use Of Dynamic Surgical Guidance Assist With Accurate Pedicle Screw Placement In Patients With Osteoporosis Or Osteopenia? Coluna/Columna. 2020;19(3):189-93
6 – Suess O, Schomacher M. Control of Pedicle Screw Placement with an Electrical Conductivity Measurement Device: Initial Evaluation in the Thoracic and Lumbar Spine. Advances in Medicine. 2016;2016:4296294. doi:10.1155/2016/4296294.
7 – Heimen K. Prospektive Untersuchung der Schraubenpositionierung bei Spondylodesen zwischen Bildwandler gesteuerter (Standard) und Schraubenplatzierung mittels induktivem Pfriem. DWG meeting 2014
8 – Bai YS et al. Comparison of the Pedicle Screws Placement Between Electronic Conductivity Device and Normal Pedicle Finder in Posterior Surgery of Scoliosis. J Spinal Disord Tech. 2013 Aug;26(6):316-20.
9 – Chaput C et al. Prospective, Randomized Trial of a New Pedicle Drilling Probe that Measures Electrical Conductivity and Reduces Radiation Exposure. Spine 2012 Oct 15; 37(21): E1314–E1321.
10 – Chang V et al. Clinical application of a specialized hand held pedicle drilling tool for pedicle screw placement in thoraco-lumbar fusions. Poster, AANS 2009
11 – Lubansu A et al. Evaluation of a hand-held pedicle drilling tool for help in the posterior pedicle screw placement. Belgian Society of Neurosurgery annual meeting, Leuven, Belgium, March 2006
12 – Bocquet Jean-François and Violas Philippe. “Pedicle screw placement in spinal surgery at lumbar level: interest of guidance by conductivity measurement in the placement of 104 pedicle screws.” EuroSpine Annual Meeting. Istanbul, Turkey. 28-25 Oct. 2006. IMAST Annual Meeting. Athens, Greece. 12-15 Jul. 2006. Poster presentation.
13 – Chang V et al. Clinical application of a specialized hand held pedicle drilling tool for pedicle screw placement in thoraco-lumbar fusions. Poster, AANS 2009
14 – Ovadia D et al. The Contribution of an Electronic Conductivity Device to the Safety of Pedicle Screw Insertion in Scoliosis Surgery. Spine (Phila Pa 1976). 2011 Sep 15;36(20):E1314-E1321
15 – Sharan A et al. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 15: Electrophysiological monitoring and lumbar fusion. J Neurosurg Spine. 2014 Jul;21(1):102-5.
16 – Ajiboye RM et al. Spine (Phila Pa 1976). Spine (Phila Pa 1976). 2017 Jul 1;42(13):1006-1010.
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Neurological Complications
Neurological Complications
