THE ROLE OF DISTRACTION IN IMPROVING THE SPACE AVAILABLE FOR THE CORDIN CERVICAL SPONDYLOSIS

Study Design. This study analyzed the effects of distraction via strut graft insertion on the canal dimensions in spondylotic human cadaver cervical spines. Transverse and anteroposterior diameters and cross-se ctional areas were measured by transverse computed tomography imaging before and after distraction without direct decompression. Objectives. This experiment was designed to address whether distraction across th e disc space without direct canal decompression can improve the space available for the cord. Summary of Background Data. Smith-Robinson ant erior discectomy and fusion have been shown to improve clinical sympto ms of radiculopathy and myelopathy in the absence of direct decompress ion. This has been postulated to be the result of gradual resorption o f intruding osteophytes. However, the immediate effects of indirect di straction alone have not been previously investigated. Methods. Four c adaver spines from elderly donors were harvested intact. The transvers e diameter, anteroposterior diameter, and cross-sectional area of the spinal canal were measured before and after discectomy and distraction via insertion of fibular strut graft by digitization of contiguous co mputed tomography scan slices. Results. The spinal canal dimensions be fore distraction were found to vary in a sinusoidal pattern around the disc space, with the maximum measurements located at the pedicle and the minimum measurements at the spondylotic ridge above or below the d isc space. Distraction via strut graft insertion significantly increas ed the anteroposterior diameter and cross-sectional area, but had a ne gligible effect on transverse diameter. Conclusions. Anterior discecto my and distraction with a strut graft can significantly improve the sp ace available for the cord in cervical spondylosis. Osteophyte debride ment, which risks iatrogenic injury to the cord, may not always be nec essary for improving clinical radiculopathy and myelopathy.