Table 5.

Preoperative and postoperative changes

Pre- Postoperative changes	All	Neck pain (+)	Neck pain (–)	p
Change in VAS (cm)	–1.3±3.5	2.4±2.3	–2.9±2.6	<0.001
JOA recovery rate (%)	52.6±36.5	40±44.8	58.3±30.8	0.024
CSA atrophy rate (%)
CPEMs at C3/4 level	2.9±29.8	1.8±23.7	3.5±32.3	0.798
CPEMs at C4/5 level	2.4±29.1	–3.7±18.4	5.2±32.6	0.176
CPEMs at C5/6 level	–2.6±25.4	–6.6±12.5	–0.7±29.3	0.299
Total CPEMs	0.5±25.8	–3.3±15.2	2.2±29.3	0.344
Trapezius at C3/4 level	12.1±22.8	16±21.8	10.4±23.3	0.276
Trapezius at C4/5 level	4.1±26.1	4.1±22.3	4.1±27.8	0.994
Trapezius at C5/6 level	7.5±14.9	16.7±11.7	3.3±14.4	<0.001
Total trapezius	8.3±14.3	12.8±13.2	6.2±14.4	0.041

Values are mean ± SD for each group.

Change in VAS: postoperative VAS – preoperative VAS

JOA recovery rate: (postoperative JOA – preoperative JOA)/(17- preoperative JOA)×100

CSA atrophy rate: (preoperative CSA – postoperative CSA)/preoperative CSA×100

Total: C3/4+C4/5+C5/6

JOA score: Japanese Orthopaedic Association score

CSA: cross-sectional area

CPEMs: cervical posterior extensor muscles

VAS: visual analog scale