Dr Mannaerts, a double Dutch board certified Gastro-intestinal as well as Oncology surgeon, is the chief of general surgery in Tawam Hospital (UAE). He is the director of the high volume bariatric center in Tawam Hospital, which has with 750 cases in 2017 done the highest annual number of cases in the Gulf region. Besides that he is the lead of the surgical oncology unit in Tawam Hospital.

He is known from the international fast-track bariatric courses in Rotterdam, The Netherlands, and is the lead investigator in multiple large randomised controlled trials, leading to over 70 Pubmed registered publications. He has performed a PhD on the multimodal treatment of locally advanced rectal and locally recurrent rectal cancer (ISBN 90-367-1418-4).