Inclusion Criteria:  >18 years diagnosed with a unilateral or bilateral diaphragm paralysis based on isolated phrenic nerve injury.  Unilateral or bilateral diaphragm paralysis is defined as follows: complaints of dyspnea and / or orthopnea combined with a drop in VC of more than 15% when change from upright to supine position and a positive sniff test during fluoroscopy or ultrasonography. A positive sniff test means that the diaphragm stands still or even moves in cranial direction (paradoxical movement ) during the sniff inspiratory maneuver.  Ability to provide written consent Time between diagnosis and treatment should be at least 1 year  Exclusion Criteria:  Patients diagnosed with a unilateral or bilateral diaphragm paralysis due to a more systemic neurological or neuromuscular disorder like for example Amyotrophic Lateral Sclerosis , Hypercapnia during daytime (PaCO2 > 6.0 kPa) Radiotherapy of the thorax Contra indication for diaphragm surgery.