A proposed technique for intraoperative measurement of cervical spine stiffness

Edmund Frank, David Chamberland, Brian Ragel

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


OBJECTIVE: Classically cervical biomechanical data have been obtained using cadaver models. Few methods exist for in vivo measurement of cervical biomechanics. A technique for intraoperative measurement of cervical motion segment stiffness (load-axial displacement) has been developed, enabling load/displacement data to be obtained during surgery at the spinal levels operated on and at adjacent cervical levels. METHODS: The instrument used for measuring motion segment stiffness was a vertebral retractor equipped with displacement and strain transducers and designed to be placed over the shafts of Caspar distraction screws. Stiffness was measured under simulated anterior cervical surgical conditions. RESULTS: A preliminary study deciphering axial cervical spine load/displacement data on 12 cadavers was performed with this instrument. Using a distraction load of 88.8640 N, axial displacements of 2.110 ± 0.258 mm (mean ± standard error of the mean) at C3-C4, 2.367 ± 0.304 mm at C4-C5, and 2.207 ± 0.238 mm at C5-C6 were found. When data were evaluated for age, there was a significant decrease in stiffness with advancing age in two of the three spinal segments tested (P < 0.05 for C3- C4, P < 0.04 for C4-C5, P < 0.12 for C5-C6), which correlated with previous studies. CONCLUSION: These results suggest that this technique may be useful in assessing intraoperative motion-segment stability.

Original languageEnglish (US)
Pages (from-to)147-150
Number of pages4
Issue number1
StatePublished - Jul 1996
Externally publishedYes


  • Intraoperative measurement
  • Load displacement curve
  • Spinal instability
  • Stiffness

ASJC Scopus subject areas

  • Medicine(all)


Dive into the research topics of 'A proposed technique for intraoperative measurement of cervical spine stiffness'. Together they form a unique fingerprint.

Cite this