Assessment Of Changes In Cervical Lordosis Following Anterior Versus Posterior Approach Cervical Spine Operations:A Retrospective Clinical Study

Background: The normal cervical curvature is a lordosis,beginning at the dens and ending at C7,which averages 34° ± 9° between C2-C7 posterior vertebral body lines in adults.Loss of normal cervical Lordosis occurs primarily in various disease processes and trauma of cervical spine,and secondarily in conditions of the thoracolumbar spine as well as in diseases and deformities of the lower limbs.An optimal outcome of operation for cervical spondylosis or deformity and patient’s satisfaction level depend,to some extent,on correction and reconstruction of cervical lordosis.Therefore,besides treating the neurological aberrations and clinical manifestations in patients with cervical spine pathologies,the main goal of surgical treatment is to establish an ideal cervical lordosis in order to maintain appropriate sagittal balance and head and neck posture as well as horizontal gaze.Objective: The main objectives of this study are:(1)To assess and compare postoperative reestablishment of Cervical Lordosis on anterior versus posterior Approach Operations.(2)To solve controversy regarding which approach to choose in cases where both anterior and posterior approach operations are equally indicated.Study Design: This was a Retrospective Comparative clinical Study,in which cervical Cobb angles at operation site(segmental cervical sagittal alignment)and overall(regional)cervical lordosis were measured in preoperative and postoperative radiographs in neutral upright positions in two groups,anterior approach(Group A)and posterior approach(Group B).Methodology: A total of 75(n=75)patients who underwent cervical spine operations between 2010/01/01 and 2016/10/01,were studied in a retrospective study.The patients were divided into two groups,Group A(n=44,30 male and 14 female)who were treated with anterior approach operations and Group B(n=31,23 male and 8 female)who were treated with posterior approach operations.The mean ages for Anterior and posterior groups were 53.7(ranging from 42 to77 years)and 61.5(ranging from 30 to 84 years)respectively.Pre-and Post-Operative Cervical Cobb angles were measured for both groups,at operation site(segmental),as well as for overall(regional)cervical lordosis from inferior endplate of C2 to inferior endplate of C6 or C7,depending on clear visibility of the X-Ray images.All measurements were recorded in excel sheets.The data was analyzed using Statistical Package for Social Sciences(SPSS)Version 20,IBM Inc.software.Result: Both operation site(segmental)Cobb angle and overall(regional)cervical lordosis in Group A and Group B were compared using independent Samples T-Test,in which the mean differences of the two groups(Anterior and posterior Approach)were compared.The P value was 0.001 or P< 0.05,which means the difference was statistically significant or post-operative Cobb angle was increased more on anterior approach cervical operations than on posterior approach operations or cervical lordosis was corrected on anterior better than posterior approach operations.Conclusion: Anterior approach cervical spine operations yield a better lordosis than the posterior approach operations and both segmental/operation-site Cobb angle and overall/regional cervical lordosis improve better on anterior approach.