SKU: PediGuard



Importance of Safe Screw Placement

Pedicle screw-based stabilization has become the gold standard for treating spinal instabilities and deformities. However, accuracy of pedicle screw placement remains a critical issue in spine surgery. In recently published papers studying screw placement accuracy:

  • The average rate of misplaced screws is around 20%when using conventional techniques. (Tian 2011, Gelalis 2012, Verma 2010, Mason 2014).
  • The average rate of misplaced screws is around 7% when using navigation. (Tian 2011, Gelalis 2012, Verma 2010, Mason 2014).
  • In a study performed in NY (USA) (Sarwahi 2014) , up to 25% of patients had at-risk screws: adjacent to blood vessels, pleura, esophagus, diaphragm or trachea.

Consequences of misplaced pedicle screws cannot be underestimated: Misplaced pedicles screws can lead to neurologic or vascular complications. Recently published clinical studies suggest that:

  • 2-11% of patients have complications related to misplaced screws. (Gelalis 2012, Verma 2010, Amato 2010, Amiot 2000, Waschkle 2013, Sarlak 2009, Sarwahi 2014, Oh 2013, Koktekir 2014, Nevzati 2014)
  • In patient with deformity, revision surgery due to screws at risk for the aorta was recommended in 4.7% (7/148) to 5.9%(6/101) of the patients. (Sarlak 2009, Sarwahi 2014)




Revision and Economic Impact

  • The rate of revision surgery to rectify misplaced screws ranges from 1 to 8%. (Amato 2010, Amiot 2000, Waschke 2013, Sarlak 2009, Sarwahi 2014, Koktekir 2014, Nevzati 2014)
The additional cost of one revision surgery to correct a misplaced screw ranges from $17,650 to $27,677. (Hodges 2012, Watkins 2010, Sanborn 2012) These studies do not
include indirect costs such as health care visits, diagnostic imaging, medication and injection.


DSG™ (Dynamic Surgical Guidance) Technology

The DSG Technology is based on the principle that the electrical conductivity of tissue varies by the type of tissue. Electrical conductivity is the property of a material to conduct an electrical current. E.g.,:

  • Cortical bone has low conductivity
  • Cancellous bone has medium conductivity
  • Periosteum and blood have high conductivity

This parameter, varying conductivity, can be very helpful in differentiating between various tissue types while drilling a pedicle prior to screw placement.

How does the PediGuard® probe work?

A bipolar sensor is embedded at the tip of each PediGuard probe. A low frequency and low voltage current is pulsed through an electrode in the probe. Based on the local conductivity, the sensor can accurately inform the surgeon of the type of tissue the tip is in. This in turn can alert the surgeon prior to a cortical breach during pedicle preparation. The surgeon is informed in real time of the tissue type by changes in the pitch and cadence of an audio signal and a flashing LED light. All PediGuard probes have been programmed such that they will emit an audio signal of:

  • Low pitch at a slow cadence in cortical bone
  • Medium pitch at a medium cadence in cancellous bone
  • High pitch at a fast cadence in periosteum and blood



Electrical Conductivity




Signal interpretation







The science behind the one of the most accurate and user-friendly technologies for pedicle screw placement is shown in the video by Dr Ferraris from the Werner-Wicker-Klinik, Bad Wildungen, Germany.






The PediGuard® probes are the only devices that incorporate the DSG Technology. These probes are the only stand-alone, handheld devices that can detect possible vertebral cortex perforation during pedicle preparation for screw placement. The PediGuard probes can alert the surgeon prior to a breach by accurately analyzing the electrical conductivity of the surrounding tissues in real time. This, in turn, can prevent a cortical breach, and also help the surgeon to redirect the probe and advance down the desired path.

The PediGuard probes are available in a wide range of shapes and sizes to address varying patient anatomies and various surgical procedures and approaches: PediGuardPediGuard Curved, and PediGuard Cannulated.

All the PediGuard probes let the surgeon:

  • Hear and feel what they cannot see
  • Be reassured that the trajectory of drilling is optimal
  • Anticipate possible breaches of the pedicle or vertebral body cortex
  • Redirect, as necessary, with complete confidence




The straight versions of the PediGuard probe include various tip shapes and diameters, and lengths to assist the surgeon in preparing the pedicle for screw placement at any level of the spine. The different tip diameters are Ø2.5 mm, Ø3.2 mm and Ø4.0 mm.

The PediGuard (Ø2.5 mm) XS probe addresses the challenges of penetrating hard bone with sharp cutting flutes at its tip. This probe can also be helpful in preparing small and/or narrow pedicles. The last graduated mark on this probe is 40 mm from the tip.







The curved versions of the PediGuard probe include a tapered tip. The tapered shape of the PediGuard Curved probe enhances the ease of penetrating through bone. Additionally, the curved shape at the distal end of the probe allows the surgeon to redirect the probe as necessary. The gradually increases from Ø2.5 mm at the tip to Ø4.0 mm at 30mm from the tip. The last graduated mark on the probe is 55 mm from the tip.

The PediGuard Curved XS probe is intended to facilitate preparation of small pedicles, while maintaining greater flexibility in directing the probe as it is being advanced down the pedicle. In this probe, the tip size gradually increases from Ø2.0 mm at the tip to Ø2.3 mm at 20mm. The last graduated mark on the probe is 50 mm from the tip.

The PediGuard Curved probe offers the following benefits:

  • A tapered tip to ease penetration through the pedicle and removal from the pedicle when drilling is complete.
  • A sense of directionality: as surgeons become comfortable with the direction of the curve, they can be aware of the location of a possible breach, and hence allow proper redirection.
  • Surgeons who prefer a curved gearshift will appreciate the tactile feel of the PediGuard Curved probe.






 The PediGuard Cannulated probe is designed primarily for helping surgeons reduce radiation exposure during minimally-invasive (percutaneous) procedures. This probe can also be used to access and drill narrow and small pedicles.

This version of the PediGuard probe includes two parts – a modified Jamshidi needle, which incorporates the sensors, and a detachable handle, which houses the brains of the probe. The detachable handle improves surgical access and space by optimizing visualization during fluoroscopy and muting the probe when not needed to help direct in the drilling process. Additionally, the handle is designed to be ergonomic for enhanced surgeon grip. The teeth and conical shape of the cannula tip improves bone penetration and cannula stability. The universal Luer-lock thread at the cannula head eases stylet insertion and removal.

The Jamshidi needles embedded with the DSG Technology sensors are available with either the trocar or beveled tip design. The beveled-tip needle is intended to improve docking in bone and improve the surgeon’s ability to redirect while advancing the needle (with handle) through the pedicle. Needles of both designs are available in two lengths, the last graduated marks on the needles are 120mm and 160mm from the tip.