Written by By A. Jay Khanna, MD, MBA of Johns Hopkins Orthopaedic and Spine Surgery in the Greater Washington Region. Dr. Khanna is a spine surgeon and Associate Professor of Orthopaedic Surgery and Biomedical Engineering at the Johns Hopkins University.
As discussed in our related article, Radiation Exposure in Spine Surgery, the minimization of radiation exposure should be a concern for spine surgeons and other medical professionals who use fluoroscopy for guidance during surgical procedures. Listed below are 11 tips that I use (many of which I learned from others and are described in the literature) to help minimize the radiation exposure to me, my assistants and the operating room staff during spine procedures.
1. Monitor and minimize the number of seconds of fluoroscopy used for each case.
• System engineers commonly say that any system improves if it is merely monitored; there is often not a need for a specific intervention. This is true in the case of fluoroscopy time.
• As you "score" yourself at the end of each case with the number of seconds of fluoroscopy used in both planes, you will find ways to decrease fluoroscopy use over time.
• The tips that follow provide specific examples of how to reduce fluoroscopy time. In addition to the "hands-off" technique described below, you should also consider whether additional fluoroscopy images (presumably to help optimize the safety and effectiveness of the procedure) are "worth" the additional risk in terms of radiation exposure.
2. Use the "hands-off" technique when acquiring images.
• It can be very tempting to obtain multiple fluoroscopic images during the advancement of a single screw or even live fluoroscopy during the placement of cement during a vertebral augmentation procedure. Instead, acquire the image while your hands aren't on surgical instruments.
• Acquiring images when no hands are on a surgical instrument will make it less convenient to acquire images and lead to a decrease in the total number of images, likely without any loss of safety and accuracy.
• Removing hands from the instrument will allow the surgeon to step away from the image intensifier and avoid being directly in or adjacent to the radiation pathway.
3. Ensure that you are wearing a high quality lead apron and thyroid shield.
• Although it is mandatory for the hospital or surgical center to regularly check the quality of lead, I suspect that many lead aprons may not be as effective as surgeons expect. This may be due to poor handling of the apron over time (i.e. folding, cracking, etc.) and lead that has outlived its suggested life expectancy.
• Many surgeons select the lightest weight lead possible to avoid fatigue, especially for long cases. Keep in mind that new lighter materials are available which provide the same level of shielding as previous-generation heavier lead.
• My lead is 0.5mm thick and is made of a light material called Burlite, which is also available in a 0.35mm and 0.25mm thickness. My understanding is that even lighter materials are available although they are less durable and, thus, must be replaced every year or two. The heavier materials are more durable and have greater life spans.
• If you decide not to purchase wrap-around lead, as I have, be aware of radiation exposure when your back is turned to the radiation source.
4. Use lead glasses during procedures that are fluoroscopy intensive.
• In my practice this includes the placement of percutaneous pedicle screws (especially long constructs), minimally invasive TLIFs, minimally invasive direct lateral access ALIFs and vertebral augmentation procedures.
• Cataract risk is high for specialists who are frequently exposed to radiation.
• The eye is the only organ for which the radiation dose risk is cumulative over a person's lifespan (i.e. there is not an annual maximum such as for other organs).
5. Maximize distance from the image intensifier.
• As you know, radiation dose falls off as 1/r2, where "r" is the distance from the radiation source. Thus, there is a marked decrease in radiation dose for every foot one steps away from the radiation source.
• Thus, if you are placing a percutaneous pedicle screw and your assistant is simply watching, he or she should be encouraged to step away from the field (and vice versa).
• The "hands-off" technique (described above) greatly helps with this.
• Encourage those who are not scrubbed into the case (anesthesiologist, circulating nurse, implant representatives, neuromonitoring staff, etc.) to avoid the direct radiation path if possible. I suggest that they use someone who is scrubbed into the case to "set the pick" between them and the radiation source so that there is an additional barrier. Many of these personnel are in the OR with radiation every day of the week.
6. Use the "low dose" mode.
• Many physicians are not aware that there is a "low dose" mode on most fluoroscopy units. The radiation dose in this mode is less than that in the standard mode.
• I have a difficult time discerning the difference in image quality between the two modes and use the standard mode only for images at the lumbosacral junction in the most obese or muscular patients.
7. Ask the fluoroscopy technician to collimate and center all images.
• Circular or parallel collimation at the level of interest markedly decreases radiation exposure and scatter and leads to a much higher quality image, especially in obese patients.
8. If possible, stand on the "correct" side of the table.
• The radiation source is at the "small side" of the fluoroscopy unit and this is the side we like to stand on so that we can avoid the large footprint of the fluoroscopy unit console. The greatest radiation exposure occurs on the side of the radiation source due to the combination of primary radiation and scatter radiation, especially with obese patients.
• In most cases, it is best to stand on this higher-risk side, but one should be aware of this and take opportunities to work on the opposite side if a particular case allows (i.e. vertebral augmentation or percutaneous pedicle screw placement).
9. Wear your radiation badge.
• This is the best way to formally monitor your monthly and annual radiation exposure and therefore take steps to decrease it.
10. Consider avoiding the use of fluoroscopy to perform of large volumes of procedures that are very radiation-dependent.
• Examples of such procedures include vertebral augmentation (vertebroplasty and kyphoplasty), percutaneous pedicle screw placement (especially for long constructs) and anterior, lumbar and thoracic fusions via minimally invasive direct lateral access approaches.
11. Consider the use of image guidance systems instead of fluoroscopy when performing procedures that are radiation-dependent.
• Image guidance systems that are based on intraoperative 3-D fluoroscopy or pre-operative CT imaging have the potential to help maintain safety and efficacy during spine surgery while avoiding the deleterious effects of radiation exposure.
• The barriers to adoption of such systems include the capital expense, learning curve and the initial effect on workflow (which improves with time and experience).
• Such systems have markedly improved over the past five to 10 years and I suspect that they will be better accepted as the use of fluoroscopy continues to increase, especially for minimally invasive spine surgery procedures.
If you have other tips that you feel the readership of Becker's Orthopedic and Spine Review may benefit from, please send them to Laura at Laura@beckershealthcare.com for our review and we will consider adding them to this list.
Please see our related article on this topic: Radiation Exposure in Spine Surgery.
References:
International Commission on Radiological Protection.1990 Recommendations of the International Commission on Radiological Protection.1991; 91.
Mroz TE, Abdullah KG, Steinmetz MP, Klineberg EO, Lieberman IH.Radiation Exposure to the Surgeon During Percutaneous Pedicle Screw Placement.Journal of Spinal Disorders and Techniques, 2010.
Rampersaud YR, Foley KT, Williams S, Solomito. Radiation Exposure to the Spine During Fluoroscopically Assisted Pedicle Screw Insertion. Spine 2000 15;25:2637-45.
United State Department of Labor: Occupational Safety and Health Administration. Toxic and Hazardous Substances: Ionizing Radiation. 1996;1910:1096.
As discussed in our related article, Radiation Exposure in Spine Surgery, the minimization of radiation exposure should be a concern for spine surgeons and other medical professionals who use fluoroscopy for guidance during surgical procedures. Listed below are 11 tips that I use (many of which I learned from others and are described in the literature) to help minimize the radiation exposure to me, my assistants and the operating room staff during spine procedures.
1. Monitor and minimize the number of seconds of fluoroscopy used for each case.
• System engineers commonly say that any system improves if it is merely monitored; there is often not a need for a specific intervention. This is true in the case of fluoroscopy time.
• As you "score" yourself at the end of each case with the number of seconds of fluoroscopy used in both planes, you will find ways to decrease fluoroscopy use over time.
• The tips that follow provide specific examples of how to reduce fluoroscopy time. In addition to the "hands-off" technique described below, you should also consider whether additional fluoroscopy images (presumably to help optimize the safety and effectiveness of the procedure) are "worth" the additional risk in terms of radiation exposure.
2. Use the "hands-off" technique when acquiring images.
• It can be very tempting to obtain multiple fluoroscopic images during the advancement of a single screw or even live fluoroscopy during the placement of cement during a vertebral augmentation procedure. Instead, acquire the image while your hands aren't on surgical instruments.
• Acquiring images when no hands are on a surgical instrument will make it less convenient to acquire images and lead to a decrease in the total number of images, likely without any loss of safety and accuracy.
• Removing hands from the instrument will allow the surgeon to step away from the image intensifier and avoid being directly in or adjacent to the radiation pathway.
3. Ensure that you are wearing a high quality lead apron and thyroid shield.
• Although it is mandatory for the hospital or surgical center to regularly check the quality of lead, I suspect that many lead aprons may not be as effective as surgeons expect. This may be due to poor handling of the apron over time (i.e. folding, cracking, etc.) and lead that has outlived its suggested life expectancy.
• Many surgeons select the lightest weight lead possible to avoid fatigue, especially for long cases. Keep in mind that new lighter materials are available which provide the same level of shielding as previous-generation heavier lead.
• My lead is 0.5mm thick and is made of a light material called Burlite, which is also available in a 0.35mm and 0.25mm thickness. My understanding is that even lighter materials are available although they are less durable and, thus, must be replaced every year or two. The heavier materials are more durable and have greater life spans.
• If you decide not to purchase wrap-around lead, as I have, be aware of radiation exposure when your back is turned to the radiation source.
4. Use lead glasses during procedures that are fluoroscopy intensive.
• In my practice this includes the placement of percutaneous pedicle screws (especially long constructs), minimally invasive TLIFs, minimally invasive direct lateral access ALIFs and vertebral augmentation procedures.
• Cataract risk is high for specialists who are frequently exposed to radiation.
• The eye is the only organ for which the radiation dose risk is cumulative over a person's lifespan (i.e. there is not an annual maximum such as for other organs).
5. Maximize distance from the image intensifier.
• As you know, radiation dose falls off as 1/r2, where "r" is the distance from the radiation source. Thus, there is a marked decrease in radiation dose for every foot one steps away from the radiation source.
• Thus, if you are placing a percutaneous pedicle screw and your assistant is simply watching, he or she should be encouraged to step away from the field (and vice versa).
• The "hands-off" technique (described above) greatly helps with this.
• Encourage those who are not scrubbed into the case (anesthesiologist, circulating nurse, implant representatives, neuromonitoring staff, etc.) to avoid the direct radiation path if possible. I suggest that they use someone who is scrubbed into the case to "set the pick" between them and the radiation source so that there is an additional barrier. Many of these personnel are in the OR with radiation every day of the week.
6. Use the "low dose" mode.
• Many physicians are not aware that there is a "low dose" mode on most fluoroscopy units. The radiation dose in this mode is less than that in the standard mode.
• I have a difficult time discerning the difference in image quality between the two modes and use the standard mode only for images at the lumbosacral junction in the most obese or muscular patients.
7. Ask the fluoroscopy technician to collimate and center all images.
• Circular or parallel collimation at the level of interest markedly decreases radiation exposure and scatter and leads to a much higher quality image, especially in obese patients.
8. If possible, stand on the "correct" side of the table.
• The radiation source is at the "small side" of the fluoroscopy unit and this is the side we like to stand on so that we can avoid the large footprint of the fluoroscopy unit console. The greatest radiation exposure occurs on the side of the radiation source due to the combination of primary radiation and scatter radiation, especially with obese patients.
• In most cases, it is best to stand on this higher-risk side, but one should be aware of this and take opportunities to work on the opposite side if a particular case allows (i.e. vertebral augmentation or percutaneous pedicle screw placement).
9. Wear your radiation badge.
• This is the best way to formally monitor your monthly and annual radiation exposure and therefore take steps to decrease it.
10. Consider avoiding the use of fluoroscopy to perform of large volumes of procedures that are very radiation-dependent.
• Examples of such procedures include vertebral augmentation (vertebroplasty and kyphoplasty), percutaneous pedicle screw placement (especially for long constructs) and anterior, lumbar and thoracic fusions via minimally invasive direct lateral access approaches.
11. Consider the use of image guidance systems instead of fluoroscopy when performing procedures that are radiation-dependent.
• Image guidance systems that are based on intraoperative 3-D fluoroscopy or pre-operative CT imaging have the potential to help maintain safety and efficacy during spine surgery while avoiding the deleterious effects of radiation exposure.
• The barriers to adoption of such systems include the capital expense, learning curve and the initial effect on workflow (which improves with time and experience).
• Such systems have markedly improved over the past five to 10 years and I suspect that they will be better accepted as the use of fluoroscopy continues to increase, especially for minimally invasive spine surgery procedures.
If you have other tips that you feel the readership of Becker's Orthopedic and Spine Review may benefit from, please send them to Laura at Laura@beckershealthcare.com for our review and we will consider adding them to this list.
Please see our related article on this topic: Radiation Exposure in Spine Surgery.
References:
International Commission on Radiological Protection.1990 Recommendations of the International Commission on Radiological Protection.1991; 91.
Mroz TE, Abdullah KG, Steinmetz MP, Klineberg EO, Lieberman IH.Radiation Exposure to the Surgeon During Percutaneous Pedicle Screw Placement.Journal of Spinal Disorders and Techniques, 2010.
Rampersaud YR, Foley KT, Williams S, Solomito. Radiation Exposure to the Spine During Fluoroscopically Assisted Pedicle Screw Insertion. Spine 2000 15;25:2637-45.
United State Department of Labor: Occupational Safety and Health Administration. Toxic and Hazardous Substances: Ionizing Radiation. 1996;1910:1096.