Efficacy of Platelet-Rich Plasma in Retarding Intervertebral Disc Degeneration: A Meta-Analysis of Animal Studies

Table 4

Subgroup analysis of T2 weighted MRI image based on animal species, study design, disc degeneration model, and follow-up period.

Subgroup analysis index	Number of studies	SMD	95% CI	value
Animal species
Rabbit	5		,	0.000	68.9%
Study design
N-RCT	1		,	0.001	NA
RCT	4		,	0.000	47.5%
Disc degeneration model
Nucleus pulposus aspiration	1		,	0.001	NA
Needle puncture	4		,	0.000	93.5%
Follow-up period
2 weeks	2		,	0.784	96.0%
6 weeks	1		,	0.000	NA
8 weeks	1		,	0.001	NA
12 weeks	1		,	0.000	NA

RCT: randomized controlled trial; N-RCT: nonrandomized controlled trial. SMD: standardized mean difference; 95% CI: 95% confidence interval.