Table 2.

Patient Demographics and Postoperative Outcomes after Propensity Score Matching.

		1F group		2F group		≥3F group
		P	R	P	R	P	R
No. of patients		4	4	6	6	11	11
Age (years)		71.3±6.0	70.0±3.6	69.8±4.0	72.8±8.6	71.0±8.3	69.9±10.3
Estimated blood loss (mL)		225±123.3	224.5±130.8	531.8±216.3	584.7±219.5	1256±867	1098±789
Duration of operation (min)		220.0±21.1	210.0±20.5	265.5±54.4	280.2±36.5	397.2±154.2	410.5±149.2
Preoperative pain domain on the JOABPEQ		28.3±37.6	50.0±44.3	19.0±21.9	47.7±43.0	68.0±37.4	57.0±36.9
Preoperative VAS
	Low back pain	61.7±13.5	62.5±28.8	71.0±27.6	59.5±19.2	59.5±17.5	57.0±36.9
	Lower extremity pain	76.7±29.1	60.0±24.5	79.3±17.9	67.3±19.8	48.0±34.7	51.2±42.9
	Lower extremity numbness	82.7±30.0	55.5±30.6	50.3±34.1	44.6±32.8	65.1±37.5	49.0±34.2
Postoperative Pain domain on the JOABPEQ		100±0*	21.5±24.8	71.0±0*	31.2±36.8	78.5±27.3	66.7±28.0
Postoperative VAS
	Low back pain	3.7±13.5*	55.0±40.1	28.3±6.7*	48.6±27.7	18.3±25.5	23.3±25.5
	Lower extremity pain	0±0*	74.3±17.1	27.7±14.7*	57.6±30.9	11.0±14.3	37.7±37.4
	Lower extremity numbness	35.7±27.6	48.3±44.4	19.8±39.5	20.3±23.7	20.6±24.0	27.3±30.1

Data are expressed as mean±standard deviation. *P<0.05. 1F, 1-segment fusion; 2F, 2-segment fusion; ≥3F, ≥3-segment fusion; JOABPEQ, ASD: adjacent segment disease; Japanese Orthopedic Association Back Pain Evaluation Questionnaire; PS, pedicle screw; VAS, visual analog scale