Low Dose Radiation 3D Intraoperative Imaging - How Low Can We Go? An O-Arm ®, CT Scan, Cadaveric Study

Vishal Sarwahi, Monica Payares, Stephen Wendolowski, Beverly Thornhill, Beverly Ann Thornhill, Yungtai Lo

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

STUDY DESIGN.: Cadaveric study OBJECTIVE.: The objective was to evaluate O-Arm®ʼs ability at low dose settings to assess intraoperative screw placement. SUMMARY OF BACKGROUND DATA.: Accurate placement of pedicle screws is crucial because of proximity to vital structures. Malposition of screws may result in significant morbidity and potential mortality. O-arm® provides real-time, intra-op imaging of patientʼs anatomy and provides higher accuracy in scoliosis surgeries, avoiding risk to vital structures. We hypothesize using low or ultra-low doses to obtain intraop images allows for accurate assessment of screw placement, both minimizing radiation exposure and preventing screw misplacement. METHODS.: 8 cadavers were instrumented with pedicle screws bilaterally from T1 to S1. Screws were randomly placed using O-arm® navigation into 3 positions: contained within the bone, OUT-anterior/lateral, OUT-medial. O-arm® images obtained at 3 dosage settings: low-dose (LD) (kvp120/mAs125 - lowest manufacturer recommended), very-low dose (VLD) (kvp120/mAs63) and ultra-low dose (ULD) (kvp120/mAs39). CT scan was performed using institutionʼs low-dose protocol (kvp100/mAs50) and gross dissection to identify screw positions. RESULTS.: LD, VLD, ULD, and CT for identifying “IN” screws relative to gross dissection had, a mean (SD) sensitivity of 84.2% (+/−5.7), specificity of 76.1% (+/−9.3), and accuracy of 79.9% (+/− 3.1) from all three observers. Across the three observers, the inter-observer agreement was 0.67 (0.61–0.72) for LD, 0.74 (0.69–0.79) for VLD, 0.61 (0.56–0.66) for ULD, and 0.79 (0.74–0.84) for CT. Effective doses of radiation (mSV) for low-dose O-arm® scan was 2.16, very-low dose 1.08, ultra-low 0.68, and our low-dose CT protocol was 1.05. CONCLUSIONS.: Accuracy of pedicle screw placement is similar for O-arm® at all doses and CT compared to gross dissection. Inter-observer reliability was substantial for very-low dose and CT. However, approximately 30% of medial screw breaches are misclassified. Ultra-low and very-low doses can be used for intraop navigation and evaluation purposes within these limitations.Level of Evidence: 3

Original languageEnglish (US)
JournalSpine
DOIs
StateAccepted/In press - Mar 14 2017

Fingerprint

Dissection
Radiation
Scoliosis
Cadaver
Anatomy
Morbidity
Bone and Bones
Mortality
Pedicle Screws
CT protocol
Radiation Exposure

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Clinical Neurology

Cite this

Low Dose Radiation 3D Intraoperative Imaging - How Low Can We Go? An O-Arm ®, CT Scan, Cadaveric Study. / Sarwahi, Vishal; Payares, Monica; Wendolowski, Stephen; Thornhill, Beverly; Thornhill, Beverly Ann; Lo, Yungtai.

In: Spine, 14.03.2017.

Research output: Contribution to journalArticle

@article{895a0f1e362f40549d2c48c2829f29a1,
title = "Low Dose Radiation 3D Intraoperative Imaging - How Low Can We Go? An O-Arm {\circledR}, CT Scan, Cadaveric Study",
abstract = "STUDY DESIGN.: Cadaveric study OBJECTIVE.: The objective was to evaluate O-Arm{\circledR}ʼs ability at low dose settings to assess intraoperative screw placement. SUMMARY OF BACKGROUND DATA.: Accurate placement of pedicle screws is crucial because of proximity to vital structures. Malposition of screws may result in significant morbidity and potential mortality. O-arm{\circledR} provides real-time, intra-op imaging of patientʼs anatomy and provides higher accuracy in scoliosis surgeries, avoiding risk to vital structures. We hypothesize using low or ultra-low doses to obtain intraop images allows for accurate assessment of screw placement, both minimizing radiation exposure and preventing screw misplacement. METHODS.: 8 cadavers were instrumented with pedicle screws bilaterally from T1 to S1. Screws were randomly placed using O-arm{\circledR} navigation into 3 positions: contained within the bone, OUT-anterior/lateral, OUT-medial. O-arm{\circledR} images obtained at 3 dosage settings: low-dose (LD) (kvp120/mAs125 - lowest manufacturer recommended), very-low dose (VLD) (kvp120/mAs63) and ultra-low dose (ULD) (kvp120/mAs39). CT scan was performed using institutionʼs low-dose protocol (kvp100/mAs50) and gross dissection to identify screw positions. RESULTS.: LD, VLD, ULD, and CT for identifying “IN” screws relative to gross dissection had, a mean (SD) sensitivity of 84.2{\%} (+/−5.7), specificity of 76.1{\%} (+/−9.3), and accuracy of 79.9{\%} (+/− 3.1) from all three observers. Across the three observers, the inter-observer agreement was 0.67 (0.61–0.72) for LD, 0.74 (0.69–0.79) for VLD, 0.61 (0.56–0.66) for ULD, and 0.79 (0.74–0.84) for CT. Effective doses of radiation (mSV) for low-dose O-arm{\circledR} scan was 2.16, very-low dose 1.08, ultra-low 0.68, and our low-dose CT protocol was 1.05. CONCLUSIONS.: Accuracy of pedicle screw placement is similar for O-arm{\circledR} at all doses and CT compared to gross dissection. Inter-observer reliability was substantial for very-low dose and CT. However, approximately 30{\%} of medial screw breaches are misclassified. Ultra-low and very-low doses can be used for intraop navigation and evaluation purposes within these limitations.Level of Evidence: 3",
author = "Vishal Sarwahi and Monica Payares and Stephen Wendolowski and Beverly Thornhill and Thornhill, {Beverly Ann} and Yungtai Lo",
year = "2017",
month = "3",
day = "14",
doi = "10.1097/BRS.0000000000002154",
language = "English (US)",
journal = "Spine",
issn = "0362-2436",
publisher = "Lippincott Williams and Wilkins",

}

TY - JOUR

T1 - Low Dose Radiation 3D Intraoperative Imaging - How Low Can We Go? An O-Arm ®, CT Scan, Cadaveric Study

AU - Sarwahi, Vishal

AU - Payares, Monica

AU - Wendolowski, Stephen

AU - Thornhill, Beverly

AU - Thornhill, Beverly Ann

AU - Lo, Yungtai

PY - 2017/3/14

Y1 - 2017/3/14

N2 - STUDY DESIGN.: Cadaveric study OBJECTIVE.: The objective was to evaluate O-Arm®ʼs ability at low dose settings to assess intraoperative screw placement. SUMMARY OF BACKGROUND DATA.: Accurate placement of pedicle screws is crucial because of proximity to vital structures. Malposition of screws may result in significant morbidity and potential mortality. O-arm® provides real-time, intra-op imaging of patientʼs anatomy and provides higher accuracy in scoliosis surgeries, avoiding risk to vital structures. We hypothesize using low or ultra-low doses to obtain intraop images allows for accurate assessment of screw placement, both minimizing radiation exposure and preventing screw misplacement. METHODS.: 8 cadavers were instrumented with pedicle screws bilaterally from T1 to S1. Screws were randomly placed using O-arm® navigation into 3 positions: contained within the bone, OUT-anterior/lateral, OUT-medial. O-arm® images obtained at 3 dosage settings: low-dose (LD) (kvp120/mAs125 - lowest manufacturer recommended), very-low dose (VLD) (kvp120/mAs63) and ultra-low dose (ULD) (kvp120/mAs39). CT scan was performed using institutionʼs low-dose protocol (kvp100/mAs50) and gross dissection to identify screw positions. RESULTS.: LD, VLD, ULD, and CT for identifying “IN” screws relative to gross dissection had, a mean (SD) sensitivity of 84.2% (+/−5.7), specificity of 76.1% (+/−9.3), and accuracy of 79.9% (+/− 3.1) from all three observers. Across the three observers, the inter-observer agreement was 0.67 (0.61–0.72) for LD, 0.74 (0.69–0.79) for VLD, 0.61 (0.56–0.66) for ULD, and 0.79 (0.74–0.84) for CT. Effective doses of radiation (mSV) for low-dose O-arm® scan was 2.16, very-low dose 1.08, ultra-low 0.68, and our low-dose CT protocol was 1.05. CONCLUSIONS.: Accuracy of pedicle screw placement is similar for O-arm® at all doses and CT compared to gross dissection. Inter-observer reliability was substantial for very-low dose and CT. However, approximately 30% of medial screw breaches are misclassified. Ultra-low and very-low doses can be used for intraop navigation and evaluation purposes within these limitations.Level of Evidence: 3

AB - STUDY DESIGN.: Cadaveric study OBJECTIVE.: The objective was to evaluate O-Arm®ʼs ability at low dose settings to assess intraoperative screw placement. SUMMARY OF BACKGROUND DATA.: Accurate placement of pedicle screws is crucial because of proximity to vital structures. Malposition of screws may result in significant morbidity and potential mortality. O-arm® provides real-time, intra-op imaging of patientʼs anatomy and provides higher accuracy in scoliosis surgeries, avoiding risk to vital structures. We hypothesize using low or ultra-low doses to obtain intraop images allows for accurate assessment of screw placement, both minimizing radiation exposure and preventing screw misplacement. METHODS.: 8 cadavers were instrumented with pedicle screws bilaterally from T1 to S1. Screws were randomly placed using O-arm® navigation into 3 positions: contained within the bone, OUT-anterior/lateral, OUT-medial. O-arm® images obtained at 3 dosage settings: low-dose (LD) (kvp120/mAs125 - lowest manufacturer recommended), very-low dose (VLD) (kvp120/mAs63) and ultra-low dose (ULD) (kvp120/mAs39). CT scan was performed using institutionʼs low-dose protocol (kvp100/mAs50) and gross dissection to identify screw positions. RESULTS.: LD, VLD, ULD, and CT for identifying “IN” screws relative to gross dissection had, a mean (SD) sensitivity of 84.2% (+/−5.7), specificity of 76.1% (+/−9.3), and accuracy of 79.9% (+/− 3.1) from all three observers. Across the three observers, the inter-observer agreement was 0.67 (0.61–0.72) for LD, 0.74 (0.69–0.79) for VLD, 0.61 (0.56–0.66) for ULD, and 0.79 (0.74–0.84) for CT. Effective doses of radiation (mSV) for low-dose O-arm® scan was 2.16, very-low dose 1.08, ultra-low 0.68, and our low-dose CT protocol was 1.05. CONCLUSIONS.: Accuracy of pedicle screw placement is similar for O-arm® at all doses and CT compared to gross dissection. Inter-observer reliability was substantial for very-low dose and CT. However, approximately 30% of medial screw breaches are misclassified. Ultra-low and very-low doses can be used for intraop navigation and evaluation purposes within these limitations.Level of Evidence: 3

UR - http://www.scopus.com/inward/record.url?scp=85015196291&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85015196291&partnerID=8YFLogxK

U2 - 10.1097/BRS.0000000000002154

DO - 10.1097/BRS.0000000000002154

M3 - Article

C2 - 28296816

AN - SCOPUS:85015196291

JO - Spine

JF - Spine

SN - 0362-2436

ER -