3.3. Assessment of quality
We evaluated the quality of the fourteen included documents according to IHE case series methodological quality evaluation tool. The result was that the thirteen articles ranged from 45% to 65% respectively, all of which were lower than 70% and were of low quality. Only one article met 70%, considered acceptable quality. These articles were all retrospective studies with few cases and without control group, intervention and blind method, so they were rated as low quality. However, there were only these documents at present, we had no choice but to include them. The literature quality assessment is shown in Table 2.