Mechanomyography for Intraoperative Assessment of Cortical Breach During Instrumented Spine Surgery

Hesham Mostafa Zakaria, Kelly M. Tundo, Carla Sandles, Matthew Chuang, Lonni Schultz, Todd Aho, Muwaffak Abdulhak

Research output: Contribution to journalArticlepeer-review


Objective: We sought to determine the utility of mechanomyography (MMG) in detecting and preventing pedicle breach in instrumented lumbar spine surgery. Methods: In a prospective nonrandomized trial without controls, we selected consecutive patients to undergo intraoperative MMG during instrumented lumbar spine surgery. MMG testing was performed at the original pilot hole, after tapping, and after screw placement, with the minimum current to elicit a recorded MMG response. All patients underwent a postoperative computed tomography scan, and a single radiologist interpreted each pedicle to identify breach. Chi-square test was used to compare patients with and without breaches. Two sample Student's t-tests were used to compare changes in functional outcomes. Sensitivity and specificity of MMG were computed using receiver operating characteristic curve analysis. Results: There were 122 consecutive instrumented lumbar surgery patients enrolled, with a total of 890 lumbar pedicle screws tested with MMG. The medial or inferior breach rate was 2.25%, with no statistically significant difference in Oswestry Disability Index or visual analog scale between patients who breached and who did not. For the MMG measurement from the original pilot hole, the area under the receiver operating characteristic was 0.835; the maximum combination of sensitivity (80.42%) and specificity (80.6%) was found using MMG current ≤12 mA. We found that an MMG cutoff of >12 mA resulted in a 99.5% likelihood of no medial or inferior breach. Conclusions: MMG can be safely used during instrumented lumbar spine surgery. A cutoff value of >12 mA for MMG can accurately predict and prevent medial and inferior pedicle screw breach.

Original languageEnglish (US)
Pages (from-to)e252-e258
JournalWorld neurosurgery
StatePublished - Sep 2018
Externally publishedYes


  • Electromyography
  • Instrumentation
  • Intraoperative monitoring
  • Mechanomyography
  • Pedicle breach
  • Spine surgery
  • Surgical morbidity

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


Dive into the research topics of 'Mechanomyography for Intraoperative Assessment of Cortical Breach During Instrumented Spine Surgery'. Together they form a unique fingerprint.

Cite this