(a).

Variable	Frequency (number, percentage)
Job
Sedentary	39, 57.4
With some level of activity	20, 29.4
Heavy	9, 13.2
Preoperative symptomatology
Neck pain	59, 86.8
Upper extremity radicular pain	59, 86.8
Sensory complaints	50, 73.5
Headache	6, 8.8
Incontinency	2, 2.9
Chest discomfort	1, 1.5
Walking disability	11, 16.2
Limb stiffness	5, 7.4
Pain duration from onset up to surgery
<3 months	24, 35.3
3–6 months	16, 23.5
6–12 months	5, 7.4
12–24 months	1, 1.5
>24 months	22, 32.4