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.

Objective-Evaluation of the capacity of lower thoracic spinal cord stimulation (SCS) to activate the expiratory muscles and generate large airway pressures and high peak airflows characteristic of cough, in subjects with tetraplegia. Design-Clinical trial.Setting-In-patient hospital setting for electrode insertion; out-patient setting for measurement of respiratory pressures; home setting for application of SCS. 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. Explanation of Disclosure:Dr. DiMarco is a Founder of and has a significant financial interest in Synapse BioMedical, Inc, a manufacturer of diaphragm pacing systems. Participants-Subjects (N = 9; 8 men, 1 woman) with cervical spinal cord injury and weak cough. Clinical Trial Registration Number: NCT00116337 Suppliers NIH Public AccessIntervention(s)-A fully implantable electrical stimulation system was surgically placed in each subject. Partial hemilaminectomies were made to place single-disc electrodes in the epidural space at the T9, T11 and L1 spinal levels. A radiofrequency receiver was placed in the subcutaneous pocket over the anterior portion of the chest wall. Electrode wires were tunneled subcutaneously and connected to the receiver. Stimulation was applied by activating a small portable external stimulus controller box powered by a rechargeable battery to each electrode lead alone and in combination.Main Outcome Measure(s)-Airway pressure and peak airflow generation achieved with SCS.Results-Supramaximal SCS resulted in large airway pressures and high peak airflow rates during stimulation at each electrode lead. Maximum airway pressures and peak airflow rates were achieved with combined stimulation of any 2 leads. At total lung capacity, mean maximum airway pressure generation and peak airflow rates were 137 ± 30 cmH 2 O (mean ± SE) and 8.6 ± 1.8 (mean ± SE) L/ s, respectively.Conclusions-Lower thoracic SCS results in near maximum activation of the expiratory muscles and the generation of high positive airway pressures and peak airflow rates in the range of those observed with maximum cough efforts in normal individuals.

Subjects continued to use the system on a long-term basis beyond the period of close follow-up and to continued derive significant clinical benefits.

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.