Development and Evaluation of a Remote Patient Monitoring System in Autologous Breast Reconstruction.

Flap monitoring after a deep inferior epigastric perforator flap breast reconstruction is crucial to detect complications in time. A novel and innovative wireless device has been developed and tested in a feasibility study. This study describes our experience with remote patient monitoring via this device in postoperative monitoring of deep inferior epigastric perforator flaps. METHODS: Following a deep inferior epigastric perforator breast reconstruction, the "Free Flap Patch" was adhered to the flap, continuously measuring temperature and tissue saturation. Data were stored locally on the patch and analyzed in a retrospective manner. Raw analog-digital-conversion values from the red- and infrared sensors, delta muscle saturation (dSmO2), and estimated tissue oxygenation (StO2) were assessed and compared with clinical records. RESULTS: No adverse events related to the device were recorded. One patient suffered flap loss; a decrease in estimated tissue oxygenation was measured with the device in situ. No deviations in clinical variables were recorded in the uncompromised flaps. CONCLUSIONS: A wearable patient monitoring device was successfully utilized in clinical practice. In one patient, a flap failure was recorded where the PPG-derived StO2 parameter was indicatory for this event. The Free Flap Patch has the potential of automatically predicting blood supply issues in an early stage. More data are needed for clinical validation.

Feasibility of error-based electrotactile and auditive feedback in prosthetic walking.

BACKGROUND AND AIM: Several studies have shown that feedback in upper-leg prostheses is possible, but slow or difficult to interpret. In this study, electrotactile and auditive error-based feedback, only giving feedback when an undesired event occurs, were tested for its use in upper-leg prosthesis when provided during a perturbation. TECHNIQUE: A total of nine healthy subjects walked on a prosthetic simulator which was disturbed at the end of the swing phase. They received either no feedback, electrotactile feedback, or auditive feedback at the time of the perturbation. DISCUSSION: The reaction time of the subjects only improved by 40 ms when using auditory feedback, compared to the no-feedback condition. No changes in reaction time were found in the electrotactile feedback condition. Considering perturbation detection was not taken into account in this study, this improvement is not enough for practical applications in upper-leg prosthesis. CLINICAL RELEVANCE: Many transfemoral amputees are insecure about their prosthesis, are afraid of falling, or actually fall. Providing feedback specifically during a perturbation may prevent them from falling, or at least give them a chance to react.

Comparison of muscle activity patterns of transfemoral amputees and control subjects during walking.

BACKGROUND: Only few studies have looked at electromyography (EMG) during prosthetic gait. Differences in EMG between normal and prosthetic gait for stance and swing phase were never separately analyzed. These differences can give valuable information if and how muscle activity changes in prosthetic gait. METHODS: In this study EMG activity during gait of the upper leg muscles of six transfemoral amputees, measured inside their own socket, was compared to that of five controls. On and off timings for stance and swing phase were determined together with the level of co-activity and inter-subject variability. RESULTS AND CONCLUSIONS: Gait phase changes in amputees mainly consisted of an increased double support phase preceding the prosthetic stance phase. For the subsequent (pre) swing phase the main differences were found in muscle activity patterns of the prosthetic limb, more muscles were active during this phase and/or with prolonged duration. The overall inter-subject variability was larger in amputees compared to controls.