Direct continuous electromyographic control of a powered prosthetic ankle for improved postural control after guided physical training: A case study.

Despite the promise of powered lower limb prostheses, existing controllers do not assist many daily activities that require continuous control of prosthetic joints according to human states and environments. The objective of this case study was to investigate the feasibility of direct, continuous electromyographic (dEMG) control of a powered ankle prosthesis, combined with physical therapist-guided training, for improved standing postural control in an individual with transtibial amputation. Specifically, EMG signals of the residual antagonistic muscles (i.e. lateral gastrocnemius and tibialis anterior) were used to proportionally drive pneumatical artificial muscles to move a prosthetic ankle. Clinical-based activities were used in the training and evaluation protocol of the control paradigm. We quantified the EMG signals in the bilateral shank muscles as well as measures of postural control and stability. Compared to the participant's daily passive prosthesis, the dEMG-controlled ankle, combined with the training, yielded improved clinical balance scores and reduced compensation from intact joints. Cross-correlation coefficient of bilateral center of pressure excursions, a metric for quantifying standing postural control, increased to .83(±.07) when using dEMG ankle control (passive device: .39(±.29)). We observed synchronized activation of homologous muscles, rapid improvement in performance on the first day of the training for load transfer tasks, and further improvement in performance across training days (p = .006). This case study showed the feasibility of this dEMG control paradigm of a powered prosthetic ankle to assist postural control. This study lays the foundation for future study to extend these results through the inclusion of more participants and activities.

The ability of MRI to predict failure of nonoperative treatment of pyogenic vertebral osteomyelitis.

Pyogenic vertebral osteomyelitis (PVO) can be treated most often by medical management. For those failing with medical management, surgical delay can result in increased morbidity. Therefore, the ability to predict failure of medical management on presentation would greatly improve the outcome. This study determines the ability of the presenting magnetic resonance imaging scan to predict failure of nonoperative management at the onset of treatment. A cohort of patients with PVO, initially treated medically, was reviewed. Imaging, demographics, and clinical data of patients successfully treated medically were compared with those ultimately requiring surgical treatment. The extent of signal change on the T1-weighted sagittal images of the affected motion segment was determined for each group. Twenty-two patients were included in the study. Patients successfully treated medically averaged 57%+/-19% of motion segment involvement, whereas those failing conservative treatment averaged 89%+/-18%. Using 90% involvement as an indication for initial surgery would have a sensitivity of 78% and specificity of 93%. Patients with thoracolumbar PVO who have 90% or higher involvement of an affected motion segment should be considered for early operative management.

Accessory tragus: A report of 2 cases.

The purpose of this article was to review the embryology of the external ear, as related to the clinical finding of accessory tragus (ear tags). Medical management of the accessory tragus is discussed, as well as differential diagnoses and associated syndromes. A general clinical description of accessory tragus is described, and 2 specific cases in pediatric patients are presented.