Spinal Cord Stimulation

Abstract

Patients with spinal cord injury have an increased risk of developing respiratory tract infections as the result of expiratory muscle paralysis and consequent inability to cough. We have developed a method by which the expiratory muscles can be activated via lower thoracic and upper lumbar spinal cord stimulation to produce an effective cough mechanism. In a tetraplegic patient who required frequent (8.57+/-2.3 times per week [mean+/-SEM]) caregiver assistance to facilitate airway clearance and expectoration of secretions, three epidural electrodes were applied in the T9, T11, and L1 spinal cord regions. During stimulation at the T9 and L1 levels, airway pressures were 90 and 82 cm H2O, respectively. Peak expiratory flow rates were 6.4 L/s and 5.0 L/s; respectively. During combined (T9+L1) stimulation, airway pressure and expiratory flow rate increased to 132 cm H2O and 7.4 L/s, respectively. Addition of the third lead did not result in further increases in pressure generation. These values are characteristic of those observed with a normal subject. Because the patient is able to trigger the device independently, he no longer requires caregiver support for airway management. If confirmed in additional patients, spinal cord stimulation may be a useful method to restore an effective cough mechanism in patients with spinal cord injury.

Respiratory muscle pacing with chronically implanted intramuscular Permaloc electrodes: A feasibility study

“…In addition, clinical studies with abdominal surface electrodes and electrodes on the lower ventral side of the spinal cord have produced exhaled volumes greater than 1 L [10][11][12][13][14][15]18]. These large exhaled volumes provide a standard for comparison of alternative techniques.…”

“…In patients [10][11][12][13][14][15][16][17][18] and laboratory animals [5][6][7]19], stimulation of extradiaphragmatic respiratory muscles has been achieved with the use of ventral epidural electrodes, electrodes implanted at the spinal foramina close to the ventral roots, and surface electrodes (expiratory muscles). The feasibility of pacing upper-intercostal and abdominal muscles plus the diaphragm with chronically implanted intramuscular electrodes (Permaloc, Synapse Biomedical, Inc) * remains uncertain.…”

Respiratory responses to stimulation of abdominal and upper-thorax intercostal muscles using multiple Permaloc®electrodes

“…Clinical studies with electrodes on the abdominal surface and on the ventral side of the spinal cord have produced exhaled volumes greater than 1 L [5][6][7][8][9]. DiMarco et al attributed the large exhaled volumes during ventral spinal cord stimulation to spread of the electric field to multiple spinal levels and recruitment of multiple abdominal muscles [7].…”

“…In patients [5][6][7][8][9][10][11][12][13][14] and laboratory animals [15][16][17][18], stimulation of extradiaphragmatic abdominal and upperthoracic respiratory muscles has been accomplished centrally with spinal epidural electrodes and peripherally with implanted and surface electrodes. Although large respiratory volumes were achieved from the extradiaphragmatic muscles with both of these approaches, they have not been extended to general SCI respiratory care.…”

Effects of Electrical Stimulation of Respiratory Center in the Event of Termination of Its Natural Rhythmic Activity

“…Currently, there are a lot of investigations where restoration and maintenance of respiratory movements is carried out by direct electrical stimulation of the spinal cord. Such studies are intensely performed in both animals [3] and humans [4][5][6][7].Here we evaluated the possibility of recovering vital spontaneous rhythmic activity of the respiratory system after narcotic apnea by transcutaneous electrical stimulation of RC area in cats. …”