Table 9.

Sub-analysis evaluating patient-reported outcome measures by workers’ compensation status.

Patient Reported Outcome Measure	Timepoint	CDA WC (n=30)	CDA non-WC (n=120)	*p-value (CDA WC vs non-WC)	ACDF WC (n=30)	ACDF non-WC (n=120)	*p-value (ACDF WC vs non-WC
Mean VAS-neck	Preoperative	7.3	7.1	.827	7.3	7.2	.796
	6 weeks postop	6.6	6.4	.285	6.5	6.3	.278
	3 months postop	5.7	5.5	.317	5.8	5.6	.324
	6 months postop	4.9	4.8	.341	5.0	4.9	.374
	1-year postop	4.4	4.3	.412	4.6	4.5	.419
	2-year postop	4.0	3.9	.378	4.1	4.0	.393
	Mean Improvement	3.3	3.2	.283	3.2	3.2	.289
Mean VAS-arm	Preoperative	7.1	7.0	.796	7.2	7.1	.796
	6 weeks postop	6.2	6.1	.312	6.3	6.2	.312
	3 months postop	5.3	5.2	.346	5.4	5.3	.346
	6 months postop	4.6	4.5	.398	4.7	4.5	.398
	1-year postop	4.1	4.0	.421	4.2	4.1	.421
	2-year postop	3.8	3.7	.405	3.7	3.9	.405
	Mean Improvement	3.3	3.3	.287	3.5	3.2	.292
Median NDI	Preoperative	39	38	.412	40	39	.412
	6 weeks postop	36	34	.048	38	35	.041
	3 months postop	30	28	.032	30	28	.031
	6 months postop	25	23	.031	25	23	.042
	1-year postop	21	20	.044	22	20	.048
	2-year postop	14	12	.026	14	12	.039
	Mean Improvement	25	26	.039	26	27	.038

ACDF, anterior cervical discectomy and fusion; CDA, cervical disc arthroplasty; VAS, Visual Analog Scale; NDI, Neck Disability Index. Values represent the mean (standard deviation). Bolded values indicate significance at a 95% confidence level. *To address the differences in sample size and reduce the risk of Type I error due to multiple comparisons, Bonferroni-adjusted p-values were applied to the p-values for group comparisons between WC and non-WC cohorts within CDA and ACDF groups.