[Clinical study of enlarged anterior cervical intervertebral cone-shape decompression and fusion in the treatment of degenerative cervical kyphosis].

<b>Objective:</b> To examine the clinical effect of the enlarged anterior cervical intervertebral cone-shape decompression and fusion(EACDF) for treating degenerative cervical kyphosis (DCK). <b>Methods:</b> This study is a retrospective case series research. From September 2018 to September 2023, the data of 51 patients with DCK who underwent EACDF at Department of Orthopaedics, the Second Affiliated Hospital, Naval Medical University were analyzed retrospectively. Among the 51 patients, there were 28 males and 23 females, with an age of (61.6±9.8) years old (range:39 to 74 years), and an body mass index of (25.9±2.7) kg/m² (range:20.7 to 31.7 kg/m²). Patients underwent EACDF with expanded decompression by distracted intervertebral space, partial resections of posterior edge of vertebral body and uncinate vertebral joint. The operation duration, blood loss and length of hospital stay were recorded. The visual analog scale (VAS) of neck pain and arm pain, cervical disability index (NDI), and modified Japanese Orthopaedic Association (mJOA) score were recorded in patients before and immediately after surgery, as well as at follow-up. Imaging parameters such as C_2-7 Cobb angle of cervical global curvature, Cobb angle at the operative segment, C_2-7 sagittal vertical axis (C_2-7 SVA), T₁ slope and the height of operative segment were measured. The fusion rate and surgical complications of two groups were recorded. Fourty-five patients who underwent anterior cervical corpectomy with fusion (ACCF) during the same period were included to compare the effectiveness of deformity correction between the two groups. Repeated measures ANOVA was used for intra group data comparison and Dunnett-<i>t</i> test was used for pairwise comparison, and mixed design ANOVA was used for inter group data comparison. <b>Results:</b> All patients were successfully completed the operation. The follow-up period after surgery was (40.4±13.4) months (range:12 to 72 months). The neck pain and arm pain VAS, NDI and JOA in the two groups immediately after surgery, at 2 months, 12 months after surgery, and the final follow-up were significantly improved compared with those before operation (all <i>P</i><0.05). In both groups, postoperative the C_2-7 Cobb angle, Cobb angle at the operative segment, C_2-7 SVA, T₁ slope, and height of operative segment were significantly improved immediately after surgery, at 2 months, 12 months, and the final follow-up (all <i>P</i><0.05). The C_2-7 Cobb angle, Cobb angle at the operative segment, and height of operative segment immediately after surgery, at 2 months, 12 months, and the final follow-up in the EACDF group were significantly higher than those in the ACCF group (all <i>P</i><0.05). There were no significant differences in C_2-7 SVA and T₁ slope between the two groups(all <i>P</i>>0.05). At the final follow-up, the angle of every intervertebral space correction in the EACDF group was (9.3±1.6) °(range:6.5° to 12.3°), while in the ACCF group was (3.1±1.8) °(range:1.2° to 5.6°), with a significant difference between the two groups (<i>P</i><0.05). Patients at the both groups got bone graft fusion at the final follow-up. <b>Conclusions:</b> The clinical effect of EACDF for treating DCK is satisfactory. EACDF maybe superior to ACCF in restoring intervertebral height, correcting and maintaining cervical curvature.