Applied Anatomical Study Of Posterior Cervical Operation With Transdural Approach

Objective: The primary purpose of the current study is to provide the applied anatomy basis for the transdural approach to the lower cervical vertebr.Methods:15 cadavers were used for dissection to investigate the anatomica1 character and morphological data about lower cervical spine(C3–C7). After removal of whole posterior bony element of the cervical spine, the nerve roots of C3-C8 and the dural sac were exposed. The relative anatomy parameters of the dural sac and its contents were measured directly using vernier ca1iber and conimete.In addition, The anatomic relation between the intradural rootlets and their corresponding intervertebral discs were observed. The parameter included rootlets descending angle(RDA), dural sac width(DSW), spinal cord width(SCW), rootlets interval(RI), nerve root interval(NRI) and the nearest nerve root-corresponding disc distance(NDDnt).Results: 1)Each of the C3–C8 anterior roots consisted of 4 to 16 bundles of the rootlets, and each posterior root comprised 4 to 14 bundles of the rootlets. The number of posterior rootlets was smaller than that of the anterior ones. 2)The descending angles of the anterior rootlets and the posterior ones tended to decreas?? the lower cervical spinal cord. The descending angles of the anterior rootlets was 78.1±1.8 to 33.4±3.1 degrees from C3 to C8, and the posterior ones was 76.1±1.8 to 35.1±3.2 degrees. There is no conspicuous difference between the anterior rootlets and posterior ones. 3) In 15 cadavers, DSW: 17.03±0.51mm～18.17±0.59 mm; SCW: 11.37±0.30 mm～12.64±0.43 mm; SASW: 5.52±0.33mm～5.78±0.48mm; ARI:1.93±0.49mm～4.70±0.35 mm; PRI: 1.38±0.38mm～3.90±0.31mm; NRI: 10.54±0.75mm～12.55±0.58mm; NDDnt: -1.82±0.40 mm～4.70±0.39 mm.Conclution: 1. There is a relative surgical area for microsurgical transdural approach surgery in the lower cervical spine. 2. The anatomic relation between the intradural rootlets and their corresponding intervertebral discs was observed , to provide amatomic according for intraoperative location of disc herniation.