Search

STUDY DESIGN.: Cadaveric human cervical spine anatomic study using posterior lateral mass screw-rod instrumentation to assess foraminal enlargement via distraction techniques. OBJECTIVES.: To determine the role of posterior cervical distraction on foraminal dimensions and to ascertain the impact of this technique on segmental kyphosis. SUMMARY OF BACKGROUND DATA.: Management of cervical spondylotic radiculopathy includes removal of offending compressive structures and enlarging the neuroforamen via anterior discectomy with interbody fusion or posterior laminoforaminotomy. METHODS.: Six human cervical spines were prepared and posterior exposure performed. Lateral mass screws were inserted from C5 to C7 and a longitudinal rod attached. Distraction was applied between the screw heads at 2 mm intervals and accuracy confirmed with digitized calipers. Pre- and postdistraction computed tomography was performed including axial and reformatted images. Foraminal area, height, and width and sagittal alignment and disc heights were evaluated. RESULTS.: The results suggest that minimal posterior distraction of 4 to 6 mm at C5'''C6 and C6'''C7 may enlarge the neuroforamen by 10 to 18 mm. Foraminal height and width increased minimally from baseline to maximum distraction; however, these measurements did not reach statistical significance at either level. A decrease of segmental lordosis at C5'''C6 was noted from baseline to 8 mm of distraction. Statistically significant kyphosis from baseline was present at 6 mm of distraction leading to overall 5.2 '' 1.4'' change in alignment. At C6'''C7, statistically significant kyphosis was not present until 8 mm of distraction (4.62 '' 2.23''). CONCLUSIONS.: This study suggests that posterior cervical instrumented distraction in the setting of foraminal stenosis is a reasonable supplement to direct laminoforaminotomy and nerve root decompression. Distraction leads to minimal segmental kyphosis, allowing this technique to serve as an adjunct for additional foraminal enlargement. [ABSTRACT FROM AUTHOR]