fluoroscopic radiation exposure in spine surgery · • one ortho hospital in italy, 1976-2000 •...

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Patent Pending© SafeRay Spine, LLC 2013; all rights reserved

Fluoroscopic Radiation Exposure in Spine Surgery

Robert E. Isaacs, MDDirector of Spine Surgery

Associate ProfessorDivision of Neurosurgery

Duke University


Disclosures

• Consultant– Baxano– Nuvasive– Vertera

• Stock Holder– SafeWire– VilaSpine– SafeRay Spine– Vertera– Providence

• Scientific Advisory Board– Providence

• Travel Reimbursement– Vertera

– ACSR

• Research Support– Nuvasive

• Royalties– Nuvasive

Patented / Patent Pending© SafeRay Spine, LLC 2013; all rights reserved

The ProblemIonizing radiation exposure during

interventional medical procedures using fluoroscopy is a potential health threat to

everyone near the x-ray source

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Deterministic risks (e.g., cataract, osteonecrosis)

Radiation Induced Cataract

Threshold < 500 mGy

Long-term stochastic risks (e.g., cancer)

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But, What About Spine Surgery?


Radiation is Bad…

“extent of radiation exposure in patients with AIS may elevate the lifetime risk of solid cancers to between 1.4% and 2.4%.”

“78% of the annual radiation exposure for operative patients occurs intraoperatively”

The Spine Journal 14 (2014) 1984–1990


• Prospective study measuring surgeon radiation exposure in MIS TLIF, – mean fluoroscopy time of 1.69 minutes per case– mean radiation exposure to the surgeon’s torso (under a

lead apron) of 27 mrem per case.

• Average to patient was 138 mGy

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A Single Dose of 100 mGy

HEALTH RISKS FROM EXPOSURE TO LOW LEVELS OF IONIZING RADIATIONCommittee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation - NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES


Compton Scatter


Increased cancer risk among surgeons in an orthopaedic hospital

• One Ortho Hospital in Italy, 1976-2000• Ortho – 29% risk• Exposed (not surgeons) – 6%• Not Exposed – 4%• Ortho surgeons – 5X increased risk of cancer

• Mastrangelo G, Fedeli U, Fadda E, Giovanazzi A, Scoizzato L, Saia B. Increased cancer risk among surgeons in an orthopaedic hospital. Occup Med (Lond). 2005;55:498-500.

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• Spinal surgeons can sustain a 10- to 12-fold increase in radiation exposure as compared with surgeons using fluoroscopy for nonspinal procedures.


But I’m Protected by Lead?


• Putting in OPEN fluoroscopically assisted pedicle screws gives the surgeon 13.49 mSv of whole body occupational exposure to ionizing radiation during a typical year

• A surgeon beginning his/her career at age 30 years would exceed the lifetime limit for nonclassified workers in less than 10 years.

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How Many Of You Know Your Dosimeter Readings?

In fact, how many of us wear a Dosimeter?


Results

• 59 MIS fusions were performed over 12 months

• 376 screws were placed• Average radiation dose to the patient per

screw placed was 0.50 Rem• Average radiation dose to the surgeon per

screw placed was 1.01 mRem

Can physician radiation exposure during surgery be predicted based on the patient exposure? Idler, et al SMISS 2014


Surgeon radiation exposure was found to have a linear relationship with patient exposure

Can physician radiation exposure during surgery be predicted based on the patient exposure? Idler, et al SMISS 2014

Pati

ent

Rem

/scr

ew

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What About Lead?


• Above the Thyroid Shield - 13.49 mSv/yr • Below the Thyroid Shield - 4.31 mSv/yr • So, lead gives a 2/3rds reduction


• Lead protects what is closer to the x-ray source, but the radiation that gets through is substantial

• At the waist PROTECTED by a lead apron was 27 mRem

• At the UNPROTECTED thyroid level was 32 mRem

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The SolutionUse Pulse and/or Low Dose Imaging to achieve ALARA – radiation dosing “As Low As Reasonably Achievable”

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1 PLD is Statistically Equivalent to Lead

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PLD Under Lead Over Lead

Everyone in the room, including the patient!

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The American College of RadiologyThe Society for Pediatric Radiology


Standard Dose

1 Pulse & Low Dose


Radiologists, medical physicists, registered radiologist assistants, radiologic technologists, and all supervising

physicians have a responsibility for safety in the workplace by keeping radiation exposure to staff, and to society as a whole, “as low as reasonably achievable” (ALARA) _

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Radiologists, medical physicists, registered radiologist assistants, radiologic technologists, and all supervising

physicians have a responsibility for safety in the workplace by keeping radiation exposure to staff, and to society as a whole, “as low as reasonably achievable” (ALARA) and to

assure that radiation doses to individual patients are appropriate, taking into account the possible risk from

radiation exposure and the diagnostic image quality necessary to achieve the

clinical objective.



“Detail of the pedicle is lost with the low‐dose pulsed fluoroscopy”

“For finer detail, specifically when determining the medial boundary of the pedicle on an AP view, digital spot is preferable.”

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Confidential


What Is LessRay?Pulse and Low Dose degrade image quality - LessRay can improve it to

close to full dose imaging


Components of LessRay

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Set Up


Standard Dose

1 Pulse & Low Dose

LessRay Enhanced1 Pulse & Low Dose Image


LessRay:In clinical practice, the amount of image quality improvement achieved when a Pulsed and/or Low Dose image is processed with LessRay is dependent on the clinical task, patient size, anatomical location, and clinical practice. The dose should be set at a level to which the physician is able to achieve the adequate image quality needed for the particular clinical task. A consultation with a radiologist and a physicist may aid in determining the appropriate dose settings.

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The Technology



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Low Dose

LessRay Conventional

Not 1 Pulse / Low DoseBut at

Pulse, 0.2 mA

Preservation of Image Quality with 92% Less Radiation

Images


Spine Surgeon = Non-Classified Worker

NCRP

Defines as (Age x 3.33mSv)

0.4712 mSv per Case (Some were multilevel)

If You Began Performing Kyphoplasties at age 30 and You Did Only 30 Cases/year AND NO OTHER Fluoroscopically Guided Surgeries

Would Exceed Your Total Lifetime Limit by age 38!!


Cadaveric Study • Conventional Fluoroscopy vs. LessRay

• 7 Fellowship Trained Orthopedic Spine Surgeons / Neurosurgeons

• OEC C-Arms set to 1 Pulse & Low Dose

•The Lowest Automatic Setting

Reducing Radiation an Order of Magnitude During X-Ray Intensive Spinal Procedures Using a Standard Fluoroscope I Karikari; C Brown; D.G. Anderson, SMISS 2014

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LessRay® Enhanced

Unenhanced 1 Pulse & Low Dose



LessRay® Enhanced

Unenhanced 1 Pulse & Low Dose



Results In no case did any of the physicians abandon the

LessRay enhanced images.

The average duration of fluoroscopy time for the entire procedure was 65.6s vs. 11.0s (Conventional vs LessRay-Assisted, p<0.001).

Statistically similar number of images with both methods prior to cement injection (24 vs. 21, p=0.30)

The pulsed/low dosed procedures achieved an overall

88.8% radiation reduction over conventional imaging (36.1mGy vs. 4mGy, p< 0.001).


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Radiation Per Procedure

mG

y



Digitally improvement allows the physician to use the lowest radiation settings on a C-Arm

Significantly reduces the amount of radiation exposure during a radiation intensive medical procedure when compared with conventional fluoroscopy

With the aid of image enhancement software like LessRay®, a fluoroscope can provide high quality images

with an order of magnitude less radiationwe are currently being subjected to.

Conclusions:



LessRay

Metal Elimination

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Conclusions


Lessray: ‐Improve Low Radiation Images

fluoroscopic radiation exposure in spine surgery · • one ortho hospital in italy, 1976-2000 •...

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