Abdominal functional electrical stimulation to enhance mechanical insufflation-exsufflation.

CONTEXT: Respiratory complications, attributed to the build-up of secretions in the airway, are a leading cause of rehospitalisation for the tetraplegic population. Previously, we observed that the application of Abdominal Functional Electrical Stimulation (AFES) improved cough function and increased demand for secretion removal, suggesting AFES may aid secretion clearance. Clinically, secretion clearance is commonly achieved by using Mechanical insufflation-exsufflation (MI-E) to simulate a cough. In this study the feasibility of combining AFES with MI-E is evaluated. FINDINGS: AFES was successfully combined with MI-E at eight fortnightly assessment sessions conducted with one sub-acute participant with tetraplegia. By using the signal from a pressure sensor, integrated with the MI-E device, AFES was correctly applied in synchrony with MI-E with an accuracy of 96.7%. Acute increases in exhaled volume and peak flow were observed during AFES assisted MI-E, compared to MI-E alone, at six of eight assessment sessions. CONCLUSION: The successful integration of AFES with MI-E at eight assessment sessions demonstrates the feasibility of this technique. The acute increases in respiratory function observed at the majority of assessment sessions generate the hypothesis that AFES assisted MI-E may be more effective for secretion clearance than MI-E alone.

Abdominal Functional Electrical Stimulation to Assist Ventilator Weaning in Acute Tetraplegia: A Cohort Study.

BACKGROUND: Severe impairment of the major respiratory muscles resulting from tetraplegia reduces respiratory function, causing many people with tetraplegia to require mechanical ventilation during the acute stage of injury. Abdominal Functional Electrical Stimulation (AFES) can improve respiratory function in non-ventilated patients with sub-acute and chronic tetraplegia. The aim of this study was to investigate the clinical feasibility of using an AFES training program to improve respiratory function and assist ventilator weaning in acute tetraplegia. METHODS: AFES was applied for between 20 and 40 minutes per day, five times per week on four alternate weeks, with 10 acute ventilator dependent tetraplegic participants. Each participant was matched retrospectively with a ventilator dependent tetraplegic control, based on injury level, age and sex. Tidal Volume (VT) and Vital Capacity (VC) were measured weekly, with weaning progress compared to the controls. RESULTS: Compliance to training sessions was 96.7%. Stimulated VT was significantly greater than unstimulated VT. VT and VC increased throughout the study, with mean VC increasing significantly (VT: 6.2 mL/kg to 7.8 mL/kg VC: 12.6 mL/kg to 18.7 mL/kg). Intervention participants weaned from mechanical ventilation on average 11 (sd: ± 23) days faster than their matched controls. CONCLUSION: The results of this study indicate that AFES is a clinically feasible technique for acute ventilator dependent tetraplegic patients and that this intervention may improve respiratory function and enable faster weaning from mechanical ventilation. TRIAL REGISTRATION: ClinicalTrials.gov NCT02200393.

Decreases in bone mineral density at cortical and trabecular sites in the tibia and femur during the first year of spinal cord injury.

BACKGROUND: Disuse osteoporosis occurs in response to long-term immobilization. Spinal cord injury (SCI) leads to a form of disuse osteoporosis that only affects the paralyzed limbs. High rates of bone resorption after injury are evident from decreases in bone mineral content (BMC), which in the past have been attributed in the main to loss of trabecular bone in the epiphyses and cortical thinning in the shaft through endocortical resorption. METHODS: Patients with motor-complete SCI recruited from the Queen Elizabeth National Spinal Injuries Unit (Glasgow, UK) were scanned within 5weeks of injury (baseline) using peripheral Quantitative Computed Tomography (pQCT). Unilateral scans of the tibia, femur and radius provided separate estimates of trabecular and cortical bone parameters in the epiphyses and diaphyses, respectively. Using repeat pQCT scans at 4, 8 and 12months post-injury, changes in BMC, bone mineral density (BMD) and cross-sectional area (CSA) of the bone were quantified. RESULTS: Twenty-six subjects (5 female, 21 male) with SCI (12 paraplegic, 14 tetraplegic), ranging from 16 to 76years old, were enrolled onto the study. Repeated-measures analyses showed a significant effect of time since injury on key bone parameters at the epiphyses of the tibia and femur (BMC, total BMD, trabecular BMD) and their diaphyses (BMC, cortical BMD, cortical CSA). There was no significant effect of gender or age on key outcome measures, but there was a tendency for the female subjects to experience greater decreases in cortical BMD. The decreases in cortical BMD in the tibia and femur were found to be statistically significant in both men and women. CONCLUSIONS: By carrying out repeat pQCT scans at four-monthly intervals, this study provides a uniquely detailed description of the cortical bone changes that occur alongside trabecular bone changes in the first year of complete SCI. Significant decreases in BMD were recorded in both the cortical and trabecular bone compartments of the tibia and femur throughout the first year of injury. This study provides evidence for the need for targeted early intervention to preserve bone mass within this patient group.

Isometric hip and knee torque measurements as an outcome measure in robot assisted gait training.

BACKGROUND: Strength changes in lower limb muscles following robot assisted gait training (RAGT) in subjects with incomplete spinal cord injury (ISCI) has not been quantified using objective outcome measures. OBJECTIVE: To record changes in the force generating capacity of lower limb muscles (recorded as peak voluntary isometric torque at the knee and hip), before, during and after RAGT in both acute and subacute/chronic ISCI subjects using a repeated measures study design. METHODS: Eighteen subjects with ISCI participated in this study (Age range: 26-63 years mean age = 49.3 ± 11 years). Each subject participated in the study for a total period of eight weeks, including 6 weeks of RAGT using the Lokomat system (Hocoma AG, Switzerland). Peak torques were recorded in hip flexors, extensors, knee flexors and extensors using torque sensors that are incorporated within the Lokomat. RESULTS: All the tested lower limb muscle groups showed statistically significant (p < 0.001) increases in peak torques in the acute subjects. Comparison between the change in peak torque generated by a muscle and its motor score over time showed a non-linear relationship. CONCLUSIONS: The peak torque recorded during isometric contractions provided an objective outcome measure to record changes in muscle strength following RAGT.

The spinal cord-injured patient in the medical ward.

People with spinal cord injury (SCI) suffer from the complications of paralysis in addition to the diseases of the general population. Spinal injury centres in the UK are tasked primarily with looking after newly injured patients and patients with established SCI must often turn to their local hospitals and general physicians for inpatient medical care. This paper outlines investigation and management of some of the common conditions which the physician on the general ward might expect to come across in patients with SCI and also how best to maintain the general health of the SCI patient in hospital.

Changes in pulmonary function measures following a passive abdominal functional electrical stimulation training program.

OBJECTIVE: To demonstrate the effect of a passive abdominal functional electrical stimulation (AFES) training program on unassisted respiratory measures in tetraplegia. DESIGN: Longitudinal feasibility study. SETTING: National spinal injuries unit in a university teaching hospital. PARTICIPANTS: Twelve patients with tetraplegic spinal cord injury, who could breathe independently, with reduced vital capacity and no visible abdominal movement. INTERVENTION: Three weeks of abdominal muscle conditioning using transcutaneous AFES. MAIN OUTCOME MEASURES: Forced vital capacity (FVC), forced exhaled volume in 1 second (FEV1), peak expiratory flow rate (PEF), and maximum exhaled pressure (MEP). RESULTS: Mean (SD) FVC increased by 0.36 l (0.23) during training (P = 0.0027). Mean (SD) FEV1 and PEF tended to increase by 0.18 l (0.16) and 0.39 l/seconds (0.35), respectively, but this was not significant. No significant change was found in the outcome measures during a 1-week pre-training control phase and during a 3-week post-training phase. CONCLUSIONS: The increase in FVC over the training period and the absence of change before or after training suggest that passive abdominal FES training can be used for respiratory rehabilitation in tetraplegia.

Role of peripheral quantitative computed tomography in identifying disuse osteoporosis in paraplegia.

OBJECTIVE: Disuse osteoporosis is a major long-term health consequence of spinal cord injury (SCI) that still needs to be addressed. Its management in SCI should begin with accurate diagnosis, followed by targeted treatments in the most vulnerable subgroups. We present data quantifying disuse osteoporosis in a cross-section of the Scottish paraplegic population to identify subgroups with lowest bone mineral density (BMD). MATERIALS AND METHODS: Forty-seven people with chronic SCI at levels T2-L2 were scanned using peripheral quantitative computed tomography at four tibial sites and two femoral sites, at the Queen Elizabeth National Spinal Injuries Unit, Glasgow (UK). At the distal epiphyses, trabecular BMD (BMDtrab), total BMD, total bone cross-sectional area (CSA) and bone mineral content (BMC) were determined. In the diaphyses, cortical BMD, total bone CSA, cortical CSA and BMC were calculated. Bone, muscle and fat CSAs were estimated in the lower leg and thigh. RESULTS: BMDtrab decreased exponentially with time since injury at different rates in the tibia and femur. At most sites, female paraplegics had significantly lower BMC, total bone CSA and muscle CSA than male paraplegics. Subjects with lumbar SCI tended to have lower bone values and smaller muscle CSAs than in thoracic SCI. CONCLUSION: At the distal epiphyses of the tibia and femur, there is generally a rapid and extensive reduction in BMDtrab after SCI. Female subjects, and those with lumbar SCI, tend to have lower bone values than males or those with thoracic SCI, respectively.

Improving respiration in patients with tetraplegia by functional electrical stimulation: an anatomical perspective.

Patients with tetraplegia often have respiratory complications because of paralysis of the abdominal and intercostal muscles. Functional electrical stimulation (FES) has been used to improve breathing in these patients by applying surface stimulation to the abdominal muscles. We aimed to find the best nerves to stimulate directly to increase tidal volume and make cough more effective. Surface electrodes were placed on a patient's abdominal wall to find the optimum points for surface stimulation. These positions were plotted on a transparent sheet. The abdomino-intercostal nerves were dissected in five male dissecting room cadavers matched for size with the patient. The plastic sheet was then superimposed over each of the dissections to clarify the relationship between optimum surface stimulation points and the underlying nerves. Results show that the optimum surface stimulation points overlie the course of abdomino-intercostal nerves T9, 10, and 11. The success with selecting stimulation points associated with T9, 10, and 11 is probably because of the large mass of abdominal muscle supplied by these nerves. The constant position of the nerves below the ribs makes the intercostal space a possible site for direct stimulation of the abdomino-intercostal nerves.

Spinal injuries in Scottish mountaineers.

OBJECTIVE: To identify the frequency and pattern of spinal injury sustained in mountaineering accidents. METHODS: All patients with spinal injuries sustained while mountaineering who were treated at the Queen Elizabeth National Spinal Injuries Unit from 1992 to 2001 were studied. Information was obtained from hospital notes, and each patient completed a questionnaire. RESULTS: Twenty-one patients with spinal injuries sustained in mountaineering accidents were identified. Fourteen patients (67.7%) were experienced mountaineers. Four (19.0%) were rock climbing, 6 (28.6%) were winter climbing, 6 (28.6%) were hill walking, and 5 (23.8%) were winter walking. Ten patients (47.6%) sustained cervical injuries, 5 (23.8%) sustained thoracic injuries, 5 (23.8%) sustained lumbar injuries, and 1 (4.8%) sustained cervical and lumbar injuries. Nineteen patients (90.5%) sustained fractures, 1 (4.8%) sustained a dislocation, and 1 (4.8%) sustained a fracture dislocation. Seventeen patients (81.0%) were neurologically intact, 2 (9.5%) sustained complete cord injury, and 2 (9.5%) sustained incomplete cauda equina lesions. Ten patients (47.6%) required internal fixation of their fractures. Fourteen patients (57.1%) sustained other significant injuries. CONCLUSIONS: This is the first study specifically aimed to describe patterns of spinal injuries and their outcomes in mountaineers. The group we studied had sustained fractures at differing spinal levels with no specific injury pattern. The incidence of cord injury was lower than in other spinal injury patient groups. The majority had also sustained other significant and potentially distracting injuries. Prehospital care providers should maintain a high suspicion of spinal injury in this group.