A lead for placement on a diaphragm includes a sensor assembly, a connector, and a lead body. The sensor assembly includes a housing having a first end surface and a second end surface opposite the first end surface. The first end surface is intended to contact the diaphragm. The sensor assembly includes at least one fixation structure also associated with the first end surface. The fixation structure is configured to preserve the hermetic integrity of the intrathoracic cavity. The fixation structure may extend through the diaphragm and transition to a state that forms a seal between itself and tissue of the diaphragm. Alternatively, the fixation structure may surround the sensor assembly and form a seal between itself and the surface of the diaphragm.