Introduction:
Traumatic brain injury (TBI) has got no effective treatment. Cellular therapy is the transfer of autologous or allogeneic cells or cellular material into patient(s) for treatment, showed better outcomes in TBI in several clinical and preclinical studies. We performed a meta-analysis on published articles on the topic of cellular therapy for the treatment of TBI in adult patients.

Material and Methods:
The literature search was done via selected database with no restrictions on publication year. Studies were included based on selection criteria and quality assessment. The following data were extracted from included articles; author names, publication year and place, type of study, number, sex and age of participants, type of cells used, and post-treatment follow up. The required data related to Fugl-Meyer Motor Scale (FMMS), Disability Rating Scale (DRS) and patients. Overall improvement was pooled and analyzed using RevMan (Ver.5.4.1).

Results:
Five studies that met the selection criteria and considered as high quality, containing 367 participants, with an average follow up time of (7.58±6.93) months, were included in meta-analysis. The results showed that cellular therapy significantly improves (OR=0.26; 95% CI=0.15 to 0.48; P=0.0001) the overall performance of the patients. Moreover, the improvements in FMMS (MD=3.79; 95% CI= -2.53 to 10.10; P=0.24) and DRS (MD= -0.16; 95% CI= -1.51 to 1.19; P=0.82) were not statically significant, but they are obviously clinically significant.

Conclusions:
This meta-analysis suggests that cellular therapy improves the condition of TBI patients in clinic. Larger, multi-central trials are required to further confirm and detail the use of stem cells in TBI.