Interaction between a smartphone and intrathecal baclofen pump case report.

INTRODUCTION: Intrathecal Baclofen (ITB) is used for the treatment of spasticity. Pump complications are most commonly related to surgical implantation or catheter dysfunction. Less common complications include catheter access port dysfunction, motor failure from excessive wear on motor gear shafts, or a complete stall of the motor. CASE PRESENTATION: 37-year-old with T9 motor complete paraplegia with ITB presented in baclofen withdrawal. Workup revealed that the pump's motor was not turning, requiring pump replacement. Questioning revealed that he had not undergone any MRI studies within the past six months, but that he recently purchased a new iPhone. The phone was 2-3 inches away from the pump for up to twelve hours a day, carried in a fanny pack around his waist. DISCUSSION: We present a case of motor pump failure from long term exposure to a magnetic field from a new iPhone. The ability of iPhones to overpower an ITB pump magnet is not widely known. In 2021, the Food and Drug Administration published a report regarding the effects of magnets in consumer electronics on implanted medical devices, recommending that such electronics should be kept at least 6 inches from the device. Providers should be aware of the ability of new models of commonly used electronic devices to stall the ITB motor to avoid life-threatening complications of baclofen withdrawal.

Compensatory mechanisms in below-knee amputee gait in response to increasing steady-state walking speeds.

Compensatory mechanisms in below-knee amputee gait are necessary due to the functional loss of the ankle muscles, especially at higher walking speeds when the mechanical energetic demands of walking are greater. The objective of this study was to examine amputee anterior/posterior (A/P) ground reaction force (GRF) impulses and joint kinetics across a wide range of steady-state walking speeds to further understand the compensatory mechanisms used by below-knee amputees. We hypothesized that amputees would rely more on their intact leg to generate greater propulsion relative to the residual leg, which would result in greater GRF asymmetry between legs as walking speed increased. Amputee and control subject kinematic and kinetic data were collected during overground walking at four different speeds. Group (n=14) average amputee data showed no significant differences in braking or propulsive GRF impulse ratios, except the propulsive ratio at 0.9 m/s, indicating that the subjects maintained their initial levels of GRF asymmetry when walking faster. Therefore, our hypothesis was not supported (i.e., walking faster does not increase GRF loading asymmetry). The primary compensatory mechanism was greater positive residual leg hip joint power and work in early stance, which led to increased propulsion from the residual leg as walking speed increased. In addition, amputees had reduced residual leg positive knee work in early stance, suggesting increased output from the biarticular hamstrings. Thus, increasing residual leg hip extensor strength and output may be a useful mechanism to reduce GRF loading asymmetry between the intact and residual legs.

The effect of foot and ankle prosthetic components on braking and propulsive impulses during transtibial amputee gait.

OBJECTIVE: To assess the influence of energy storage and return (ESAR) prosthetic feet and multi-axis ankles on ground reaction forces and loading asymmetry between lower limbs in transtibial amputees. DESIGN: Subjects wore 2 different prosthetic feet with and without a multi-axis ankle and were analyzed using a blind repeated-measures multivariate analysis-of-variance design. SETTING: Gait analysis laboratory. PARTICIPANTS: Fifteen healthy unilateral transtibial amputees (>55 y) who had an amputation at least 1 year before testing because of vascular disorders. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The anteroposterior ground reaction force impulse, peak ground reaction forces, and braking and propulsion impulse duration were analyzed as subjects walked at a self-selected speed while wearing each of the 4 foot-ankle prosthesis combinations. Statistical analyses were used to determine if there was a significant foot, ankle, or foot-ankle interaction effect on the outcome measures for each foot (P<.05). RESULTS: Amputees generated a significantly greater propulsive impulse with the residual leg when wearing a multi-axis ankle with the ESAR and non-ESAR foot, which improved the propulsive symmetry between the residual and intact legs. There was no prosthetic foot effect on these measures. There were no significant differences in the peak residual-leg braking or propulsive ground reaction forces or the impulse durations due to the prosthetic foot, ankle, or foot-ankle interactions, although an increase in the propulsive impulse duration approached significance (P=.062) with a multi-axis ankle. CONCLUSIONS: These results suggest that amputee gait may improve with the prescription of multi-axis ankles that allow for greater propulsive impulses by the residual leg, which improve the loading symmetry between legs.

Kinetics of high-heeled gait.

A within-subject comparative study of walking while wearing low-heeled sports shoes versus high-heeled dress shoes was performed to identify and describe changes in lower-extremity joint kinetics associated with wearing high-heeled shoes during level overground walking. A volunteer sample of 15 unimpaired female subjects recruited from the local community underwent quantitative measurement of sagittal and frontal plane lower-extremity joint function, including angular motion, muscular moment, power, and work. When walking in high-heeled shoes, a significant reduction in ankle plantar flexor muscle moment, power, and work occurred during the stance phase, whereas increased work was performed by the hip flexor muscles during the transition from stance to swing. In the frontal plane, increased hip and knee varus moments were present. These differences demonstrate that walking in high-heeled shoes alters lower-extremity joint kinetic function. Reduced effectiveness of the ankle plantar flexors during late stance results in a compensatory enhanced hip flexor "pull-off" that assists in limb advancement during the stance-to-swing transition. Larger muscle moments and increased work occur at the hip and knee, which may predispose long-term wearers of high-heeled shoes to musculoskeletal pain.