An Animal Model for the Study of Compressive (Constrictive) Cervical Radiculopathy

Purpose: The purpose of this study was to investigate the basis for the clinical and anatomical findings associated with C7 cervical radiculopathy in an animal model. In the diabetic population cervical radiculopathy is particularly more severe and symptomatic, especially C7. Materials and Methods: A total of 60 Sprague-Dawley rats were randomly divided into six groups of 10 each. In each group, the nerve roots of C4, C5, C6, C7 and cervical plexus were exposed under the operating microscope with general anesthesia with pentobarbital and ketamine. Group 1 served as the sham operation group. In groups II-VI, different cervical roots were exposed and ligated by using 9.0 nylon at the point where they emerged from the foramina. In Group II C5, C6, and C7 were exposed and ligated, in Group III C4 was litigated, in Group IV C5 was ligated, in Group V C6 was ligated, and in Group VI C7 was ligated. Results: After six weeks of ligation Groups III, IV and V improved and the allodynia completely resolved. In Groups II and VI improvement was noted but never recovered to the level of the other groups. Allodynia and hypoesthesia persisted throughout the study period. Conclusion: Ligation of cervical roots independently or in combination can produce syndromes that resemble human CRPS I and II (International Association for Study of Pain Criteria), but the changes are more pronounced and persistent with C7 involved primarily or in combination with other roots