The impact of plating level on the postoperative loss of cervical lordosis in alternative skipped-level plating laminoplasty.

Abstract

The aim of this study is to evaluate the impact of plating level on the loss of cervical lordosis (LCL) after laminoplasty with skipped-level plating. This retrospective study included patients who underwent alternative skipped-level plating laminoplasty from C3 to C6. Patients were divided into two groups according to the plating level. Group 1 had miniplate fixed at C3 and C5 (C3/C5 group), while patients in group 2 were fixed at C4 and C6 (C4/C6 group). The outcome of interest was the difference of LCL between the two groups; meanwhile, kyphosis development after laminoplasty was also compared. A total of 70 patients were included in our study with a mean age of 60.44 ± 9.97 years. The median follow-up was 15 (12, 16) months. Median lordosis was 15.43° (9.35°, 22.23°) before surgery and 9.88° (4.15°, 18.94°) after, with a median LCL of 4.48° (-0.66°, 8.11°). There were 17 patients in the C3/C5 group, whereas 53 patients in the C4/C6 group. While preoperative C2-C7 Cobb's angle was comparable between the two groups (15.32° (9.73°, 23.84°) vs. 15.51° (9.03°, 21.70°), <i>p</i> = 0.864), there were statistical differences regarding postoperative C2-C7 Cobb's angle (6.54° (2.49°, 16.42°) vs. 10.62° (5.89°, 18.85°), <i>p</i> = 0.006) and LCL (4.74° (4.17°, 12.03°) vs. 4.07° (-1.89°, 6.69°), <i>p</i> = 0.034) between the C3/C5 group and the C4/C6 group. In all, 94.1% (16 of 17) of patients showed some degree of LCL after laminoplasty in the C3/C5 group, which was significantly higher when compared with 64.2% (34 of 52) of C4/C6 group (<i>p</i> = 0.038). Before surgery, there were no kyphosis patients in either the C3/C5 group or the C4/C6 group. Postoperatively, four patients (23.5%) developed kyphotic alignment in the C3/C5 group, but only one (1.9%) in the C4/C6 group (<i>p</i> = 0.013). Cervical alignment was compromised after laminoplasty. When alternative skipped-level plating is adopted in laminoplasty from C3 to C6, plating at C4/C6 may better preserve cervical lordosis than plating at C3/C5 after surgery.