Lower Thoracic Spinal Cord Stimulation to Restore Cough in Patients With Spinal Cord Injury: Results of a National Institutes of Health–Sponsored Clinical Trial. Part II: Clinical Outcomes

Abstract

Objective-To evaluate the clinical effects of spinal cord stimulation (SCS) to restore cough in subjects with cervical spinal cord injury.Design-Clinical trial assessing the clinical outcomes and side effects associated with the cough system. Setting-Out-patient hospital or residenceParticipants-Subjects (N = 9; 8 men, 1 woman) with cervical spinal cord injury Disclosure: We certify that we have affiliations with or financial involvement (eg, employment, consultancies, honoraria, stock ownership or options, expert testimony, grants and patents received or pending, royalties) with an organization or entity with a financial interest in, or financial conflict with, the subject matter or materials discussed in the manuscript and all such affiliations and involvements are disclosed on the title page of the manuscript. Intervention(s)-SCS was performed at home by either the subjects themselves or caregivers on a chronic basis and as needed for secretion management. Explanation ofMain Outcome Measure(s)-Ease in raising secretions, requirement for trained caregiver support related to secretion management and incidence of acute respiratory tract infections.Results-The degree of difficulty in raising secretions improved markedly, and the need for alternative methods of secretion removal was virtually eliminated. Subject life quality related to respiratory care improved with subjects reporting greater control of breathing problems and enhanced mobility. The incidence of acute respiratory tract infections fell from 2.0 ± 0.5 to 0.7 ± 0.4 events/ subject year (p < 0.01), and mean level of trained caregiver support related to secretion management measured over a 2 week period decreased from 16.9 ± 7.9 to 2.1 ± 1.6 and 0.4 ± 0.3 times/week (p < 0.01) at 28 and 40 weeks following implantation of the device, respectively. Three subjects developed mild hemodynamic effects which abated completely with continued SCS. Subjects experienced mild leg jerks during SCS, which were well tolerated. There were no instances of bowel or bladder leakage.Conclusion(s)-Restoration of cough via SCS is safe and efficacious. This method improves life quality and has the potential to reduce the morbidity and mortality associated with recurrent respiratory tract infections in this patient population.

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

“…These large exhaled volumes provide a standard for comparison of alternative techniques. DiMarco et al attributed their large exhaled volumes during ventral spinal cord stimulation to the spread of the electric field to stimulate the abdominal innervation at several spinal levels [5][6]18]. Lin et al also reported that stimulation of more levels with more electrodes is important [19].…”

“…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.…”

Use of air stacking and abdominal compression for cough assistance in people with complete tetraplegia

“…Another method to normalize cough flow is electrical stimulation. Di Marco et al 24 used this technique in nine cases of cervical SCI where implants were inserted between the levels T9 and L1 and demonstrated that the pressures and the flows can reach normal values. While technology allows helping patients, there are some restrictions that must be taken into account.…”

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

“…One important limitation of phrenic nerve stimulation to generate tidal breathing is inward movement of the paralyzed upper rib cage; however, activation of upper-thoracic, external-intercostal, inspiratory muscles can ameliorate this effect [1]. Another limitation of phrenic nerve stimulation alone is the inability to recruit abdominal muscles [5][6], which are needed to produce cough. Abdominal contractions induce high expiratory velocity and flow rates for removal of respiratory secretions and are important in management of respiratory tract infections [1].…”