Transcutaneous Electrical Nerve Stimulation (TENS) for Opioid-Induced Constipation in Palliative Care: A Systematic Review and Network Meta-Analysis

Figure 3

Quality assessment of included studies; the green circles indicate lack of bias; yellow circles indicate unclear bias. (a) Risk of bias for each included study. (b) The overall summary of bias of the included studies.

(a)

(b)