Provided herein as a transoral minimally invasive method and a system thereof for the treatment of gastrointestinal diseases and/or obesity, which at least partially encircles a part of the gastrointestinal tract, such as esophagus of the patient by advancing an elongated deformable portion of a neurostimulator assembly endoluminally to the subfascial area from the outer wall of the esophagus and introducing the elongated deformable portion sub-fascially in the subfascial area, whereby at least one part of the encircled esophagus will be modulated using a modulator.