Prospective Open-label Study of the Efficacy of the Addition of Hyperbaric Oxygen to the Treatment of Patients With Perianal Fistulas Already Treated With TNF Alpha Blockers

This study is a prospective open-label study that consists three periods: screening, treatment and follow-up. After signing an informed consent, subjects will be assessed by a gastroenterologist, a surgeon (for the diagnosing the perianal disease and assessing the need for surgery) and a HBOT specialist for assessing the capability of the subject to undergo HBOT treatment.After the screening period, eligible subjects will enter an 8 weeks HBOT treatment period, combined with TNFalpha blocker treatment. This period will be followed by a 4 months follow-up period in which treatment with TNFalpha blocker will continue. All patients will have an MRI and TRUS examinations to assess the fistulas and also blood tests for CBC, chemistry, inflammatory markers and cytokine analysis. Same evaluation will be repeated at the end of the study.