A. Jay Khanna, MD, MBA of Johns Hopkins Orthopaedic and Spine Surgery in the Greater Washington Region, and Associate Professor of Orthopaedic Surgery and Biomedical Engineering at the Johns Hopkins University, discusses radiation exposure for spine surgeons. He also serves as clinical director of the Johns Hopkins Center for Bioengineering, Innovation and Design.
Question: Why should radiation exposure be a concern for spine surgeons?
Dr. A. Jay Khanna: Radiation exposure is concerning because of its potential early and late effects.The early effects associated with exposure to a large radiation dose ("deterministic" effects) include local tissue damage, hematologic effects and cytogenetic effects. The possible late effects ("stochastic" effects) include the potential for radiation induced malignancies and local tissue effects including to the skin or eyes (cataracts). Only the former are well understood, involving large, acute radiation exposure. The latter are poorly understood, subject to stochastic radiobiological effects and rely largely on extrapolation from much higher dose levels (for example, Hiroshima-Nagasaki atomic bomb survivors) for estimates of biological risk.
Radiation exposure should also be a concern to other physicians and medical professionals who are exposed to radiation in their daily practice of caring for patients. These may include interventional radiologists, interventional cardiologists, interventional pain specialists, anesthesiologists and orthopaedic surgeons, especially those with a special interest in trauma. Other medical professionals, such as nurses and operating room technicians, may be frequently exposed to radiation as well.
Q: How and how often are spine surgeons exposed to radiation?
AK: There is a great deal of variability in the amount of radiation that spine surgeons use in their surgical practice.While all interventional radiologists and cardiologists are exposed to moderate levels of radiation, I expect that the range is wider for spine surgeons.Some surgeons, including several of my partners, use minimal to no fluoroscopy or image guidance for the placement of thoracolumbar pedicle screws, even for the most complex spinal deformities. Other surgeons may use large amounts of radiation (more than several minutes) for routine cases.Although I am not familiar with any objective data on the usage rate of fluoroscopy for spine procedures, I suspect that more than half of spine surgeons use it routinely for cases that require spinal instrumentation.
You may find it interesting to note that one minute of fluoroscopy for a 70 kilogram (154 pound) patient has the radiation equivalence of 150 chest radiographs. Although all medical professionals wear lead gowns, thyroid shields (often) and lead glasses (very rarely) when exposed to radiation in the operating room, I doubt they would feel comfortable doing the same if they were standing next to a patient receiving 150 chest radiographs. Keep in mind that complex or fluoroscopy-dependent spine and orthopaedic surgery procedures may require several minutes of fluoroscopy.
Q: Can you describe a common procedure and the estimated radiation exposure associated with that procedure?
AK: The most common procedures for which I use fluoroscopy include the open and percutaneous placement of thoracolumbar pedicle screws, minimally invasive direct lateral access anterior lumbar interbody fusion, minimally invasive transforaminal lumbar interbody fusion and vertebral augmentation procedures (vertebroplasty and kyphoplasty).I also use one or two fluoroscopy images to confirm and reconfirm levels for all cases, including those without instrumentation such as lumbar microdiscectomy.
Exposure time for these procedures ranges from a few seconds (for a lumbar microdiscectomy or a cervical spine procedure) to 20 seconds (for a two or three level lumbar decompression and fusion procedure) to one or two minutes (for a minimally invasive or percutaneous procedure).
The effective radiation dose to the patient, OR staff, my assistants and me varies based on exposure time, the patient's weight and our distance from the radiation source when the images are acquired.
Q: What are some of the best practices surgeons should follow to minimize their exposure to radiation?
AK: Three key factors will allow surgeons to minimize their exposure to radiation during a spine procedure or any other surgery: time, distance, and shielding.
1. Minimization of total fluoroscopy time.
2. Maximization of distance between the image intensifier and the surgeon and other personnel.
3. Utilization of lead and other barriers to optimize shielding between the radiation source and the surgeon and other personnel.
Please see our related article on this topic: 11 Tips to Help Decrease Radiation Exposure During Spine Surgery and Other Procedures.
References:
International Commission on Radiological Protection.1990 Recommendations of the International Commission on Radiological Protection. 1991;91.
Mettler FA, Upton A, ed. Medical Effects of IonizingRadiation. 2nd ed. Philadelphia: W.B. Saunders; 1995.
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.
Pierce DA, Preston DL. Radiation-related cancer risks at low doses among atomic bomb survivors. Radiat Res. 2000;154: 178–186.
Preston DL, Ron E, Tokuoka S, et al. Solid cancer incidence inatomic bomb survivors: 1958-1998. Radiat Res. 2007;168:1–64.
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 Nations Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation: UNSCEAR 2000 report to the general assembly, with scientificannexes. 2000.
United State Department of Labor: Occupational Safety and Health Administration. Toxic and Hazardous Substances: Ionizing Radiation. 1996; 1910:1096.
Wakeford R. Radiation in the workplace-a review of studies of the risks of occupational exposure to ionisingradiation.JRadiol Prot. 2009;29:A61–A79.
Dr. A. Jay Khanna: Radiation exposure is concerning because of its potential early and late effects.The early effects associated with exposure to a large radiation dose ("deterministic" effects) include local tissue damage, hematologic effects and cytogenetic effects. The possible late effects ("stochastic" effects) include the potential for radiation induced malignancies and local tissue effects including to the skin or eyes (cataracts). Only the former are well understood, involving large, acute radiation exposure. The latter are poorly understood, subject to stochastic radiobiological effects and rely largely on extrapolation from much higher dose levels (for example, Hiroshima-Nagasaki atomic bomb survivors) for estimates of biological risk.
Radiation exposure should also be a concern to other physicians and medical professionals who are exposed to radiation in their daily practice of caring for patients. These may include interventional radiologists, interventional cardiologists, interventional pain specialists, anesthesiologists and orthopaedic surgeons, especially those with a special interest in trauma. Other medical professionals, such as nurses and operating room technicians, may be frequently exposed to radiation as well.
Q: How and how often are spine surgeons exposed to radiation?
AK: There is a great deal of variability in the amount of radiation that spine surgeons use in their surgical practice.While all interventional radiologists and cardiologists are exposed to moderate levels of radiation, I expect that the range is wider for spine surgeons.Some surgeons, including several of my partners, use minimal to no fluoroscopy or image guidance for the placement of thoracolumbar pedicle screws, even for the most complex spinal deformities. Other surgeons may use large amounts of radiation (more than several minutes) for routine cases.Although I am not familiar with any objective data on the usage rate of fluoroscopy for spine procedures, I suspect that more than half of spine surgeons use it routinely for cases that require spinal instrumentation.
You may find it interesting to note that one minute of fluoroscopy for a 70 kilogram (154 pound) patient has the radiation equivalence of 150 chest radiographs. Although all medical professionals wear lead gowns, thyroid shields (often) and lead glasses (very rarely) when exposed to radiation in the operating room, I doubt they would feel comfortable doing the same if they were standing next to a patient receiving 150 chest radiographs. Keep in mind that complex or fluoroscopy-dependent spine and orthopaedic surgery procedures may require several minutes of fluoroscopy.
Q: Can you describe a common procedure and the estimated radiation exposure associated with that procedure?
AK: The most common procedures for which I use fluoroscopy include the open and percutaneous placement of thoracolumbar pedicle screws, minimally invasive direct lateral access anterior lumbar interbody fusion, minimally invasive transforaminal lumbar interbody fusion and vertebral augmentation procedures (vertebroplasty and kyphoplasty).I also use one or two fluoroscopy images to confirm and reconfirm levels for all cases, including those without instrumentation such as lumbar microdiscectomy.
Exposure time for these procedures ranges from a few seconds (for a lumbar microdiscectomy or a cervical spine procedure) to 20 seconds (for a two or three level lumbar decompression and fusion procedure) to one or two minutes (for a minimally invasive or percutaneous procedure).
The effective radiation dose to the patient, OR staff, my assistants and me varies based on exposure time, the patient's weight and our distance from the radiation source when the images are acquired.
Q: What are some of the best practices surgeons should follow to minimize their exposure to radiation?
AK: Three key factors will allow surgeons to minimize their exposure to radiation during a spine procedure or any other surgery: time, distance, and shielding.
1. Minimization of total fluoroscopy time.
2. Maximization of distance between the image intensifier and the surgeon and other personnel.
3. Utilization of lead and other barriers to optimize shielding between the radiation source and the surgeon and other personnel.
Please see our related article on this topic: 11 Tips to Help Decrease Radiation Exposure During Spine Surgery and Other Procedures.
References:
International Commission on Radiological Protection.1990 Recommendations of the International Commission on Radiological Protection. 1991;91.
Mettler FA, Upton A, ed. Medical Effects of IonizingRadiation. 2nd ed. Philadelphia: W.B. Saunders; 1995.
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.
Pierce DA, Preston DL. Radiation-related cancer risks at low doses among atomic bomb survivors. Radiat Res. 2000;154: 178–186.
Preston DL, Ron E, Tokuoka S, et al. Solid cancer incidence inatomic bomb survivors: 1958-1998. Radiat Res. 2007;168:1–64.
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 Nations Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation: UNSCEAR 2000 report to the general assembly, with scientificannexes. 2000.
United State Department of Labor: Occupational Safety and Health Administration. Toxic and Hazardous Substances: Ionizing Radiation. 1996; 1910:1096.
Wakeford R. Radiation in the workplace-a review of studies of the risks of occupational exposure to ionisingradiation.JRadiol Prot. 2009;29:A61–A79.