A support element configured to guide the insertion and/or the extraction of a treatment medical device in/from a patient's body at a target tissue, which support element comprises: - a main body comprising a first (201; 401) and a second (202; 402) component which can be coupled together along a coupling direction, said coupling direction being orthogonal to a contact surface (201a; 401a) of said first component (201; 401) with the patient's body, - locking means (203; 403) of said first (201; 401) and second (202; 402) component, - reversible anchoring means of the support element to the patient's body, said anchoring means being interposed between said first (201; 401) and second (202; 402) component, wherein said first (201; 401) and second (202; 402) component comprise corresponding through-openings (21, 22) configured to constrain a motion of the treatment device passing through the support element and to determine at least one access point (P') on the patient's body, wherein said locking means (203; 403) are movable between an operating condition, wherein said first (201; 401) and said second (202; 402) component are relatively locked in such a way as to retain integrally therebetween said anchoring means, and a positioning condition, wherein said first (201; 401) and second (202; 402) component can be rotated and translated with respect to said anchoring means in an adjustment plane of the position of said at least one access point (P'), said adjustment plane being parallel to said contact surface (201a; 401a), characterised in that said anchoring means is made of non-woven fabric, comprises a flexible element which develops in said adjustment plane and it is provided with an adhesive surface intended to adhere to the patient's body wherein said first (201; 401) and second (202; 402) component comprise a plurality of said corresponding through-openings (21, 22) distributed in such a way as to constrain the motion of the treatment device along directions respectively parallel to each other. - a main body comprising a first (201; 401) and a second (202; 402) component which can be coupled together along a coupling direction, said coupling direction being orthogonal to a contact surface (201a; 401a) of said first component (201; 401) with the patient's body, - locking means (203; 403) of said first (201; 401) and second (202; 402) component, - reversible anchoring means of the support element to the patient's body, said anchoring means being interposed between said first (201; 401) and second (202; 402) component, wherein said first (201; 401) and second (202; 402) component comprise corresponding through-openings (21, 22) configured to constrain a motion of the treatment device passing through the support element and to determine at least one access point (P') on the patient's body, wherein said locking means (203; 403) are movable between an operating condition, wherein said first (201; 401) and said second (202; 402) component are relatively locked in such a way as to retain integrally therebetween said anchoring means, and a positioning condition, wherein said first (201; 401) and second (202; 402) component can be rotated and translated with respect to said anchoring means in an adjustment plane of the position of said at least one access point (P'), said adjustment plane being parallel to said contact surface (201a; 401a), characterised in that said anchoring means is made of non-woven fabric, comprises a flexible element which develops in said adjustment plane and it is provided with an adhesive surface intended to adhere to the patient's body wherein said first (201; 401) and second (202; 402) component comprise a plurality of said corresponding through-openings (21, 22) distributed in such a way as to constrain the motion of the treatment device along directions respectively parallel to each other.