Patients sustaining injuries to the upper spinal cord from trauma, tumors, or surgery often are unable to breathe on their own, thus requiring mechanical ventilation to sustain their lives. Ventilator dependency imparts a functional restriction on these patients, as they may never again be able to return home or perform activities of daily living. There are surgical procedures that we perform to allow these patients the ability to breathe without the ventilator, thereby restoring a sense of independence and freedom.
The underlying cause of ventilator dependency is often from injury to the phrenic nerves – the nerves that control contraction of the diaphragm muscles. When these nerves are injured, the diaphragm is paralyzed and is unable to permit expansion and contraction of the lungs for proper spontaneous breathing.
The surgical treatment for ventilator dependency involves placing an electrode around the phrenic nerves to permit stimulation using an electronic pacemaker. The electrodes are connected to an internal receiver that receives stimulus information from an external transmitter. When a stimulating pulse is transmitted, the diaphragm contracts and produces the inhalation phase of breathing. The transmitter signal then stops causing the diaphragm to relax, resulting in the exhalation phase of breathing. Under certain circumstances, the phrenic nerves cannot be paced unless preceded by nerve transfers – connecting nearby functioning nerves to the phrenic nerve – in order to successfully cause diaphragm contraction.
Read more on Spinal Cord Injuries in our patient story: