"Visiting Volunteers" may be changed to Home Visit Volunteers

"Lin Liu involves into" - get involved into

"she visited the patients who have had the Xiao Procedure" - ...who underwent Xiao Procedure

"The professional doctors were from Zhengzhou University' - doctors from Zhengzhou University Medical School

"The other two are 19-years old but they were also non-adults when they were performed surgeries" - ...when they had spinal surgery

"the parents signed their signature on the contract of the surgery risk" - ..signed a consent form before surgery

"But they did not realize what kind of risks they had taken and what kind of results they were waiting for." - without fully understanding the risk of serious complications