Electromagnetic field-based image-guided spine surgery part one: results of a cadaveric study evaluating lumbar pedicle screw placement.

Spine · 2003 · Benefit · Low evidence

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BenefitLow evidencePaper 5262

Study snapshot

PublicationSpine · 2003

Study typeother

Reported directionBenefit

Evidence ratingLow

Abstract

STUDY DESIGN: Human cadaveric. OBJECTIVES: Compare the accuracy of electromagnetic field (EMF)-based image-guided lumbar pedicle screw insertion to conventional techniques using anatomic landmarks, and fluoroscopy. BACKGROUND: Image-guided surgical systems that aid in spinal instrumentation seek to minimize radiation exposure and improve accuracy. EMF tracking-based image-guidance was developed in the hopes of eliminating line-of-sight restrictions seen with other systems. MATERIALS AND METHODS: Sixteen fresh-frozen human cadavers were randomly allocated into three groups. Pedicle screws were inserted from L1 to L5 using only anatomic landmarks in group 1, fluoroscopy in group 2, and image-guidance in group 3. Insertion and total fluoroscopic time were recorded. Anatomic dissections were performed to assess screw placement. RESULTS: Accuracy was 83%, 78%, and 95% for groups 1, 2, and 3, respectively. However, image-guided pedicle screw placement resulted in a 5% critical perforation rate whereas anatomic and fluoroscopic placement resulted in a 15% and 22% critical perforation rate, respectively. The average degree of perforation was 1.5 mm with image guidance, and 3.8 mm with fluoroscopic guidance (P < 0.05). Fluoroscopy time and insertion time per screw were not improved using image guidance. CONCLUSIONS: Our study has shown that when EMF tracking was used for image-guided lumbar pedicle screw placement, accuracy was improved and the incidence and degree of cortical perforations that may place neurovascular structures at risk was also reduced. Current system requirements for set-up and image acquisition, however, do add time to the procedure, and when factored in, do not yet result in a decrease in the use of fluoroscopy or screw insertion time.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionbenefit

PopulationFresh-frozen human cadavers (lumbar spine instrumentation)

Sample size16

ExposureNot supplied

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In 16 cadavers, EMF-based image-guided lumbar pedicle screw placement had higher accuracy (95%) than anatomic landmarks (83%) or fluoroscopy (78%). Critical perforation rates were lower with image guidance (5%) versus anatomic (15%) and fluoroscopy (22%), and average perforation was smaller than with fluoroscopy (1.5 mm vs 3.8 mm; P < 0.05). Fluoroscopy time and insertion time per screw were not improved using image guidance.

Outcomes measured

Pedicle screw placement accuracy
Critical perforation rate
Degree of perforation (mm)
Fluoroscopy time
Insertion time per screw

Limitations

Cadaveric study (not clinical outcomes in living patients)
Frequency/SAR and detailed EMF exposure parameters not reported
Fluoroscopy time and insertion time per screw not improved despite accuracy benefits

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": "electromagnetic field (EMF) tracking-based image-guidance system (surgical navigation)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Fresh-frozen human cadavers (lumbar spine instrumentation)",
  "sample_size": 16,
  "outcomes": [
    "Pedicle screw placement accuracy",
    "Critical perforation rate",
    "Degree of perforation (mm)",
    "Fluoroscopy time",
    "Insertion time per screw"
  ],
  "main_findings": "In 16 cadavers, EMF-based image-guided lumbar pedicle screw placement had higher accuracy (95%) than anatomic landmarks (83%) or fluoroscopy (78%). Critical perforation rates were lower with image guidance (5%) versus anatomic (15%) and fluoroscopy (22%), and average perforation was smaller than with fluoroscopy (1.5 mm vs 3.8 mm; P < 0.05). Fluoroscopy time and insertion time per screw were not improved using image guidance.",
  "effect_direction": "benefit",
  "limitations": [
    "Cadaveric study (not clinical outcomes in living patients)",
    "Frequency/SAR and detailed EMF exposure parameters not reported",
    "Fluoroscopy time and insertion time per screw not improved despite accuracy benefits"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "electromagnetic field tracking",
    "image-guided surgery",
    "spine surgery",
    "lumbar pedicle screw",
    "fluoroscopy",
    "cadaveric study",
    "accuracy",
    "cortical perforation"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1097/01.brs.0000087851.51547.00
PubMed: 12973150

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