Dynamic measurements of cervical neural foramina during neck movements in asymptomatic young volunteers.
OBJECTIVE
Neural foraminal dimensions are considered important in nerve root compression and development of cervical radiculopathy, but baseline data regarding their range during normal motion are not available. An in vivo study of cervical foraminal motion was conducted to characterize normal 3D dynamic foraminal dimensions during physiological neck motion and compare between different tasks and intervertebral segments.


METHODS
Biplane X-ray imaging and computed tomography-based markerless tracking were used to measure foraminal height (FH) and width (FW) from five asymptomatic subjects during neck axial rotation and extension. FH and FW were quantified as the minimum (SI.Min and AP.Min), range (SI.Range and AP.Range), and median (SI.Med and AP.Med) of superoinferior (SI) and anteroposterior (AP) dimensions for each trial and as the coefficient of variation of these variables from three trials (SI.Med.CV and AP.Med.CV, SI.Range.CV and AP.Range.CV) at C3-4 through C6-7 levels for each subject. Differences were analyzed using mixed model ANOVA.


RESULTS
AP.Range and AP.Med.CV were greater (P < 0.0001) while AP.Min and AP.Range.CV were smaller (P < 0.0006 and P < 0.0005) during neck extension than rotation. SI.Range and SI.Med.CV were greater for extension than rotation at C5-6 (P < 0.002 and P < 0.03), whereas SI.Med.CV was greater for rotation than extension at C3-4 (P < 0.03). AP.Range (P < 0.02), AP.Med.CV (P < 0.05), SI.Range (P < 0.0004), and SI.Med.CV (P < 0.02) were different between cervical levels, the latter two being during extension only.


CONCLUSIONS
Patterns of FH and FW during normal motion are different between tasks and cervical levels. These findings are expected to provide a basis for future studies of spinal degeneration and surgical efficacy.
Department of Neurosurgery, Henry Ford Hospital, K-11, 2799W. Grand Blvd, Detroit, MI, USA. vchang1@hfhs.org.
Victor
V
Chang
Department of Neurosurgery, Henry Ford Hospital, K-11, 2799W. Grand Blvd, Detroit, MI, USA.
Azam
A
Basheer
Department of Orthopedic Surgery, Henry Ford Hospital, Detroit, MI, USA.
Timothy
T
Baumer
Department of Orthopedic Surgery, Henry Ford Hospital, Detroit, MI, USA.
Daniel
D
Oravec
Department of Orthopedic Surgery, Henry Ford Hospital, Detroit, MI, USA.|Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada.
Colin P
CP
McDonald
Department of Orthopedic Surgery, Henry Ford Hospital, Detroit, MI, USA.
Michael J
MJ
Bey
Department of Orthopedic Surgery, Henry Ford Hospital, Detroit, MI, USA.
Stephen
S
Bartol
Department of Orthopedic Surgery, Henry Ford Hospital, Detroit, MI, USA.
Yener N
YN
Yeni
D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology; D011857:Radiographic Image Interpretation, Computer-Assisted; D016059:Range of Motion, Articular / Q000502:physiology*; D012399:Rotation; D014057:Tomography, X-Ray Computed; D021801:Zygapophyseal Joint / Q000000981:diagnostic imaging / Q000502:physiology
Cervical spine; Dynamic X-ray; Motion analysis; Neck extension; Neck rotation; Neural foramen