Table 2.

Comparison of clinical features and surgical outcomes in flexion K-line (+) group and flexion K-line (−) group.

	Flexion K-line (+) (n = 37)	Flexion K-line (−) (n = 9)	P
Age at operation (yr)	65.0 ± 9.7	61.8 ± 12.3	.476
Duration from onset to operation (mo)	28.2 ± 41.0	20.9 ± 37.7	.618
Occupying ratio of OPLL (%)	44.8 ± 16.0	50.4 ± 14.4	.315
Number of expanded laminae	5.5 ± 1.5	5.5 ± 1.9	.416
Preoperative JOA score	10.9 ± 1.8	10.9 ± 1.7	.952
Postoperative JOA score	14.0 ± 1.8	13.6 ± 1.2	.301
JOA score recovery rate (%)	52.4 ± 9.6	41.8 ± 9.1	.024*

JOA = Japanese Orthopaedic Association, K-line = kyphosis-line, OPLL = ossification of the posterior longitudinal ligament.

^*P < .05.