ABSTRACT
Objective:To observe the effect of distraction before discectomy (DBD) in the distraction of the height of anterior cervical space,and to explore its feasibility in restricting the over distraction.Methods:A total of 31 patients with cervical spondylotic myelopathy were treated with anterior cervical discectomy and fusion (ACDF).During surgery,the intervertebral space was distracted before discectomy,the procedure was defined as DBD technique.Before surgery,the distance from the arch top of inferior endplate of upper vertebrae of the index level to the midpoint of superior endplate of lower vertebrae was measured (H0).The same method was used to measure the adjacent proximal and distal intervertebral space heights (Hp and Hd),and the mean value of Hp and Hd,H,was regarded as a referential height that the index intervertebral space should be restored.During operation,the intervertebral space heights before (H1) and after (H2) discectomy with application of DBD were measured withthe aforementioned method.The pre-and post-operation index segment heights AB and A'B'were measured respectively.The change of index segment height was defined as △H (A'B'-AB),the index intervertebral space height after operation was defined as Hs (H0 +△H).The patients were divided into neck pain group and non-neck pain group according to their post-operative neck pain VAS scores.The radiographic data of the patients in two groups was analyzed and compared with statistical methods.Results:The post-operative neck pain incidence rate was 19.35％.During operation,after DBD,the intervertebral space height change △H1 was (1.19±0.51) mm.In non-neck pain group,the difference between H1 (6.95 mm±0.84 mm) and H (6.98 mm±0.70 mm) was not significant (P=0.80),and the difference between H2 (7.31 mm±0.90 mm) and H1 (6.95 mm± 0.84 mm) was significant (P＜0.01).In neck pain group,the difference between H2 (8.33 mm± 1.39 mm) and H1 (7.87 mm±1.35 mm) was significant (P＜0.01).In neck pain group,the △H was (3.04±0.42) mm;in non-neck pain group,the △H was (1.70±0.51) mm;the difference between two groups was significant (P＜0.01).In nonneck pain group,H1,H2 and H3 had good consistency with H.Conclusion:DBD can effectively control the distraction height of the index intervertebral space within 2 mm,also convenient to let the index intervertebral space be similar with the adjacent segment and easy to follow.