Long-term experience with implanted intrathecal drug administration systems for failed back syndrome and chronic mechanical low back pain

Table 3 Efficacy of intrathecal implants in low back pain with out prior surgery (n between 9 and 11)

Dimension	Variable	Pre-Treatment Median (Quartiles)	Post-Treatment Median (Quartiles)	Z Score^a	P value^b
Sensory	Pain	9.00 (8.00, 10.00)	6.00 (4.00, 6.00)	2.87	0.0041^*
	Pain Relief	8.00 (6.50, 9.50)	4.00 (1.50, 6.00)	2.54	0.0111
Psychological	Depression	8.00 (5.50, 10.00)	5.00 (2.00, 6.00)	2.37	0.0178
	Quality of Life	9.50 (8.00, 10.00)	6.50 (3.75, 7.25)	2.68	0.0074
	Coping	8.50 (7.75, 10.00)	6.00 (2.50, 7.00)	2.82	0.0048^*
	Dependency	8.00 (7.00, 9.00)	6.00 (5.75, 6.50)	2.72	0.0065
Sociological	Sleep	10.00 (9.00, 10.00)	7.50 (4.50, 9.00)	2.68	0.0074
	Work	10.00 (8.50, 10.00)	9.00 (6.50, 10.00)	1.84	0.0658
	Social Life	10.00 (9.00, 10.00)	8.00 (6.00, 8.00)	2.71	0.0067
	Sex Life	9.50 (7.25, 10.00)	9.00 (4.75, 10.00)	1.09	0.2757
	Driving	7.00 (3.00, 8.00)	7.00 (0.00, 8.00)	0.37	0.7114
	Housework	9.00 (7.00, 10.00)	6.00 (5.00, 8.00)	1.50	0.1336
	Mobility	9.00 (7.00, 10.00)	8.00 (6.00, 8.00)	2.84	0.0045^*

^a The Z score is converted from the Wilcoxon signed ranks test. ^b A Bonferroni adjustment for the number of tests indicates P < 0.005 (0.05/10) as significant.

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