Advice
Technology overview
Technology overview
This briefing describes the regulated use of the technology for the indication specified, in the setting described, and with any other specific equipment referred to. It is the responsibility of healthcare professionals to check the regulatory status of any intended use of the technology in other indications and settings.
About the technology
CE marking
Table 1 lists all the versions of the PediGuard available from the manufacturer, SpineGuard, with their associated CE mark status and device class.
Table 1 PediGuard products
|
Type and description |
Intended for |
Year CE mark awarded and class |
Variations |
|
Classic: features a straight shaft with a tapered tip |
Drilling pilot holes that follow a straight passage through a pedicle |
2012, ‖a |
Tri Tip 2.5XS |
|
2003, ‖a |
Tri Tip 2.5 |
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|
Tri Tip 3.2 |
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|
Tri Tip 4.0 |
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|
Curved: features a curved shaft and a tapered tip |
Drilling pilot holes that follow the natural curvature of a pedicle |
2012, ‖a |
CurvXS |
|
2010, ‖a |
Curv |
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|
Cannulated: features a straight shaft that can be cannulated and a detachable handle |
Percutaneous insertion of pedicle screws |
2011, ‖a |
Starter Stylet – Bevel |
|
2011, ‖a |
Starter Stylet – Trocar |
Description
The PediGuard is a single‑use surgical tool for drilling pilot holes in order to place pedicle screws. It can be used to drill multiple pilot holes in a single patient, as long as the device is wiped with a saline‑impregnated cloth between uses. The manufacturer states that battery life for the PediGuard allows for more than 5 hours of drilling time.
There are 3 types of PediGuard available: straight and curved for open surgeries and cannulated for minimally invasive approaches (table 1). Each has several tip length and diameter options to provide flexibility. The smaller sizes (Tri Tip 2.5XS and CurvXS) are designed to be used in small pedicles, such as in cervical vertebrae or in those of children and young people.
The PediGuard is similar in appearance to a pedicle awl; it has a stainless steel shaft with a pointed tip capable of boring through bone. The tip houses an electromagnetic bipolar sensor that responds to the electrical conductivity of the surrounding tissue. The handle contains a battery, speaker and LED; these provide audio and visual feedback in response to tissue conductivity. The feedback signals are as follows:
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Low‑pitch, low‑frequency sound: in cortical (hard) bone, such as that of the pedicle cortex.
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Medium‑pitch, medium‑frequency sound: in cancellous (spongy) bone, such as that of the inner portion of the vertebral pedicle and body.
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High‑pitch, high‑frequency sound: in soft tissues and blood.
The LED flashes at a speed corresponding to the frequency of the audio feedback.
Intended use
The PediGuard is intended for use during spinal surgery where the drilling of pilot holes is needed to place pedicle screws. The manufacturer states that the PediGuard should not be used on people with pacemakers or any other active implantable medical device, or in patients with severely osteoporotic vertebrae.
Setting and intended user
This tool is intended for use in secondary and tertiary care settings. Specifically, it would be used in operating theatres by appropriately qualified orthopaedic surgeons or neurosurgeons. Spinal surgery, particularly involving complex instrumentation, is increasingly done in tertiary centres.
Current NHS options
According to NICE's guideline on metastatic spinal cord compression patients with spinal metastases should be offered spinal surgery if:
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there is imaging evidence of structural spinal failure
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they have mechanical pain resistant to conventional analgesia.
In most cases in the UK, a surgeon drills pilot holes and places pedicle screws manually. Fluoroscopy (or, less often, intraoperative CT imaging) is commonly used to aid the placement of pedicle screws by providing real‑time anatomical information, as well as information on screw trajectory and position (Patel et al. 2011). Fluoroscopy is quantified by the number of 'shots' used. Every fluoroscopy shot exposes the patient to radiation. Neuromonitoring can also be used to help drill pilot holes, in order to test the integrity of the pedicle wall without exposing the patient to ionising radiation (Mattei et al. 2009). Some tertiary care facilities may use spinal cord monitoring, which is a type of neuromonitoring, for complex cases, such as deformity, fracture and metastatic spinal cord compression cases, as well as significant proportion of degenerative spinal cases.
NICE is not aware of other CE‑marked devices that have a similar function to the PediGuard.
Costs and use of the technology
Information on the cost of using the technology was provided by the manufacturer. The PediGuard has a NHS acquisition cost of £500 per single‑use unit, excluding VAT.
The manufacturer provides a free half‑day training course. Surgeons can also be trained by other surgeons who have used the device.
Where manual pedicle screw placement is supplemented with fluoroscopic imaging, the NHS reference cost for fluoroscopic imaging is £262 for mobile or intraoperative contrast fluoroscopy procedures lasting more than 40 minutes (NHS reference cost 2012–13 code RA21Z [DOH 2013]). When the cost of the PediGuard is added to that of fluoroscopy, the average total cost per treatment is estimated to be £762.
The current manual technique involves standard, re‑usable pedicle awls (£301.14 to £315.36, excluding VAT) or cannulated pedicle awls (£738.87 to £753.82, excluding VAT).
No other practical difficulties have been identified in using or adopting the technology.
Likely place in therapy
The PediGuard can be used in any spinal surgical procedures when drilling pilot holes is needed to place pedicle screws.
Specialist commentator comments
Two specialist commentators were concerned that severe osteoporotic bone changes were listed as a contraindication for the use of the PediGuard, and felt that this was a disadvantage of the technology. In addition, 1 of these commentators noted that the description 'severely osteoporotic' does not define a specific clinical population. The specialist stated that characterising osteoporotic bone is a surgical challenge. It was suggested that by the time a surgeon is able to recognise the true extent of a patient's bone deterioration, and so evaluate whether the PediGuard is an appropriate tool, the packaging may have already been opened.
One specialist commentator concluded that the device was simple and safe to use, with good sensitivity and specificity. However, he felt that the device was outdated, because assistive technology and percutaneously inserting pedicle screws is becoming increasingly common in the NHS. Therefore, the PediGuard's true value is likely to lie in training and for use in complex cases. Two specialist commentators stated that further research may be warranted. In particular, they suggested that further information on the cost effectiveness of the device would be invaluable.
According to 1 specialist commentator, the number of spinal surgery procedures performed for metastatic disease is increasing.
Two specialist commentators commented on the published studies of the PediGuard. One noted that in the studies by Bai et al. (2013) and Chaput et al. (2012), a primary outcome was the number of fluoroscopy shots given to each patient. The commentator found this to be a poor outcome measure because the consequence of more exposures is not known. A second commentator noted that the study by Bai et al. (2013) stated that surgeons took between 65 and 225 seconds to insert one pedicle screw. This commentator reflected that, in their experience, the average time is approximately 5 minutes (300 seconds) per screw.
One specialist noted that all studies in this field are subject to performance bias as the risk of adverse events will vary in accordance with the complexity of the procedure and the experience of the surgeon. They emphasised the importance of patient‑reported outcomes, such as pain, in the evaluation of a device like the PediGuard, noting that these may provide an accurate estimate of nerve injury rates.
One specialist commentator noted that none of the studies reported on the use of the cannulated PediGuard. The specialist stated that this is an important issue because future procedures that need the insertion of pedicle screws are likely to be performed percutaneously.
Equality considerations
NICE is committed to promoting equality and eliminating unlawful discrimination. We aim to comply fully with all legal obligations to:
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promote race and disability equality and equality of opportunity between men and women
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eliminate unlawful discrimination on grounds of race, disability, age, sex, gender reassignment, pregnancy and maternity (including women post‑delivery), sexual orientation, and religion or belief (these are protected characteristics under the Equality Act 2010).
The manufacturer states that the PediGuard should not be used on people with pacemakers or any other active implantable medical device, or on patients with severely osteoporotic vertebrae. Both of these groups of people may be considered to have a disability, which is a protected characteristic defined in the Equality Act 2010.