Is correction of segmental kyphosis necessary in single-level anterior cervical fusion surgery? An observational study

Figures & data

Figure 1 Lateral X-ray pictures showing changes in segmental angle.

Notes: (A and B) Pre- and postoperative segment angles of a patient in the correction group, respectively, and (C and D) pre- and postoperative segment angles of a patient in the noncorrection group, respectively.

Table 1 Intraobserver reproducibility and interobserver reliability using intraclass correlation coefficient

	Intraobserver	Interobserver
Segmental angle	0.84	0.81
C2–C7 angle	0.90	0.86
T1 slope	0.88	0.83
C2–C7 SVA	0.82	0.79

Notes: The intraclass coefficient value of <0.40 indicates poor, 0.40–0.75 indicates fair or good, and 0.75–1.00 indicates excellent reliability.

Abbreviation: SVA, sagittal vertical axis.

Table 2 Demographic and clinical data in patients before single-level ACDF surgery

	Noncorrection group	Correction group	P-value
Number of patients	32	149
Age (years)	51.0±8.9	48.9±10.4	0.29
Gender
Male	17	82	0.84
Female	15	67
Diagnosis
Radiculopathy	21	103	0.68
Myelopathy	11	46
Duration of symptoms (months)	21.6±11.2	24.1±12.8	0.31
Lesion location
C4–C5	7	38	0.82
C5–C6	17	70
C6–C7	8	41
Segmental angle (°)	−3.2±0.7	−3.1±0.6	0.41
C2–C7 angle (°)	12.1±8.5	12.3±7.9	0.90
T1 slope (°)	26.1±4.5	25.7±5.8	0.71
C2–C7 SVA (mm)	22.5±10.3	23.3±12.2	0.73
Preoperative NDI	21.5±5.4	21.2±6.1	0.84
Preoperative VAS neck	5.5±1.1	5.3±1.2	0.51
Preoperative VAS arm	5.7±1.6	5.8±1.4	0.78

Abbreviations: ACDF, anterior cervical discectomy and fusion; NDI, Neck Disability Index; SVA, sagittal vertical axis.

Table 3 Postoperative data in patients with single-level ACDF surgery

	Noncorrection group	Correction group	P-value
Number of patients	32	149
Segmental angle (°)	−2.0±0.4	4.3±0.6	<0.01
C2–C7 angle (°)	13.4±3.2	17.1±3.4	<0.01
T1 slope (°)	25.8±4.2	25.9±5.6	0.92
C2–C7 SVA (mm)	20.5±9.3	16.3±10.2	0.03
Postoperative NDI	12.2±3.1	10.6±3.3	0.16
Postoperative VAS neck	2.3±0.7	2.1±0.6	0.27
Postoperative VAS arm	2.3±0.3	2.4±0.4	0.40

Abbreviations: ACDF, anterior cervical discectomy and fusion; NDI, Neck Disability Index; SVA, sagittal vertical axis.

Figure 2 Correlations between the changes in segmental angle and changes in C2–C7 angle (A) as well as changes in C2–C7 SVA (B).

Abbreviation: SVA, sagittal vertical axis.