Physiotherapists’ prognosis of 1-year outcome after lumbar spinal fusion - A prospective cohort study

Figures & data

Figure 1. Flow chart of patient inclusion and patients included in the prediction analysis.

Table 1. Participant characteristics at baseline, Surgery procedure and Prognosis of physiotherapists.

	Respondents at 12 months (n = 170/207)	Excluded from the analysis (n = 37/207)
Age, mean (SD)	55.8 (13.4)	54.7 (11.6)
Female, n (%)	111 (65.3)	26 (70.27)
BMI, mean (SD)	27.7 (4.6)	29.09 (5.55)
Smoking, n (%)
Yes	28 (16.7)	7 (19.4)
No	140 (63.3)	29 (80.6)
Education, n (%)
Primary and/or secondary education	32 (18.2)	9 (24.3)
Vocational or advanced level education	27 (15.9)	5 (13.5)
Short university or college education	37 (21.8)	6 (16.2)
Medium university or college education	39 (22.9)	11 (29.7)
Long university or college education	34 (20)	5 (13.5)
Other education	1 (0.6)	1 (2.7)
Work status, n (%)
Working	72 (42.4)	13 (35.1)
Unemployed	15 (8.8)	7 (18.9)
Work ability enhancement programme	12 (7.1)	2 (5.4)
Student	1 (0.6)	0
Retirement	45 (26.5)	4 (10.8)
Incapacity benefit/early retirement	12 (7.1)	5 (13.5)
Other	13 (7.6)	6 (16.2)
Diagnosis, n (%)
Disc degeneration	44 (25.9)	8 (22.2)
Spondylosis	45 (26.5)	13 (36.1)
Spondylolisthesis	81 (47.6)	15 (41.7)
Previous back surgery, n (%)
0 occasions	117 (70.1)	19 (55.9)
1 occasion	28 (16.8)	7 (20.6)
2 occasions	11 (6.9)	6 (17.6)
3 or more occasions	11 (6.9)	2 (5.9)
Back pain duration, n (%)
No back pain	3 (1.8)	1 (2.7)
< 3 months	0	0
≥ 3 < 12 months	12 (7.1)	2 (5.4)
≥ 12 months > 24 months	30 (17.6)	5 (13.5)
≥ 24 months	125 (73.5)	29 (78.4)
Leg pain duration, n (%)
No legpain	3 (1.8)	3 (8.6)
< 3 months	2 (1.2)	2 (5.7)
≥3 < 12 months	33 (19.9)	7 (20)
≥12 months > 24 months	39 (23.5)	8 (22.9)
≥ 24 months	89 (53.6)	15 (42.9)
Back pain intensity, VAS, mean (SD)	62.53 (21.81)	66.22 (20.55)
Leg pain intensity, VAS, mean (SD)	62.20 (25.03)	56.97 (29.86)
Disability, ODI, mean (SD)	41.01 (14.74)	47.39 (16.28)
EQ-5D, mean (SD)
EQ-5D-3 L index	0.520 (0.242)	0.517 (0.218)
EQ-5D VAS	51.3 (22.9)	47.0 (21.2)

ODI: Oswestry Disability Index; VAS: Visual Analogue Scale; EQ-5D: European Quality of Life 5 dimensions

Table 2. Surgery information and PTs’ prognosis values, n = 170.

Surgical procedure, n (%)
Instrumented posterior fusion with or without intervertebral cage	151 (88.8)
Anterior intervertebral fusion	19 (11.2)
Number of fusion levels, n (%)
1 level	122 (71.8)
2 levels	48 (28.2)
Prognosis physiotherapists, n (%)
0	0 (0)
1	0 (0)
2	1 (0.6)
3	6 (3.5)
4	5 (2.9)
5	13 (7.6)
6	18 (10.6)
7	35 (20.6)
8	38 (22.4)
9	44 (25.9)
10	10 (5.9)

Table 3. Baseline, Follow-up and Change from baseline in secondary continuous outcomes, n = 170.

	Baseline, mean (SD)	1-year follow-up, mean (SD)	Change from baseline, mean (95% CI)	P-value
Disability, ODI	41.0 (14.7)	27.1 (19.6)	13.9 (11.2 to 16.6)	< 0.01
Back pain intensity, VAS	62.5 (21.8)	38.2 (28.5)	23.9 (19.2 to 28.6)	< 0.01
Leg pain intensity, VAS	62.2 (25.0)	33.2 (29.5)	29.3 (24.2 to 34.3)	< 0.01
EQ-5D-3 L index	0.520 (0.241)	0.684 (0.252)	−0.166 (−0.213 to −0.119)	< 0.01
EQ-5D VAS	51.3 (22.9)	61.1 (25.9)	−9.9 (−14.6 to −5.2)	< 0.01

ODI: Oswestry Disability Index; VAS: Visual Analogue Scale; EQ-5D: European Quality of Life 5 dimensions

Table 4. Univariate linear regression of the physiotherapists’ prognosis and the secondary outcomes one-year post-surgery, n = 170.

Dependent variables	Slope (95% CI)	P	R^2
ODI	−3.53 (−5.21 to −1.85)	< 0.01	0.09
Back pain intensity, VAS	−4.0 (−6.4 to −1.5)	< 0.01	0.05
Leg pain intensity, VAS	−2.70 (−5.3 to −0.1)	0.04	0.02
EQ-5D-3 L index	0.040 (0.018 to 0.062)	< 0.01	0.07
EQ-5D VAS	3.7 (1.4 to 5.9)	< 0.01	0.05
GPE	0.5 (0.1 to 0.80)	0.01	0.03

ODI: Oswestry Disability Index; VAS: Visual Analogue Scale; EQ-5D: European Quality of Life 5 dimensions;

GPE: Global Perceived Effect

Figure 2. Receiver operating characteristic (ROC curve) and area under the curve (AUC). Quantification of physiotherapists’ overall ability to discriminate between “Satisfied with surgery result” and “Not satisfied with surgery result”.

Table

Values at one-year follow-up	Poor prognosis (score ≤ 6), Mean (SE)	Good prognosis (score ≥7), Mean (SE)	Mean Difference (95%CI)	P-value
Disability, ODI	36.3 (3.2)	24.0 (1.6)	12.3 (5.7 to 18.9)	0.0003
Back pain intensity, VAS	48.8 (4.3)	36.6 (2.5)	14.2 (4.4 to 34.0)	0.0049
Leg pain intensity, VAS	43.4 (4.7)	29.8 (2.6)	13.6 (3.4 to 23.8)	0.0092
EQ-5D-3 L index	0.590 (0.041)	0.716 (0.022)	−0.126 (−0.213 to −0.039)	0.0046
EQ-5D VAS	48.7 (3.9)	65.3 (2.2)	−16.6 (−25.3 to −7.9)	0.0002