Abstract-Persons with an upper-limb amputation who use a body-powered prosthesis typically control the prehensor through contralateral shoulder movement, which is transmitted through a Bowden cable. Increased cable tension either opens or closes the prehensor; when tension is released, some passive element, such as a spring, returns the prehensor to the default state (closed or open). In this study, we used the Southampton Hand Assessment Procedure to examine functional differences between these two types of prehensors in 29 nondisabled subjects (who used a body-powered bypass prosthesis) and 2 persons with unilateral transradial amputations (who used a conventional body-powered device). We also administered a survey to determine whether subjects preferred one prehensor or the other for specific tasks, with a long-term goal of assessing whether a prehensor that could switch between both modes would be advantageous. We found that using the voluntary closing prehensor was 1.3 s faster (p = 0.02) than using the voluntary opening prehensor, across tasks, and that there was consensus among subjects on which types of tasks they preferred to do with each prehensor type. Twenty-five subjects wanted a device that could switch between the two modes in order to perform particular tasks.

With the vastly growing market for OI and OC materials commonly used in lumbar spinal fusions, the options for surgical treatment for degenerative spondylolisthesis are ever expanding. No significant difference was found when comparing fusion rates between the two types of materials in this retrospective analysis. Interestingly, TLIF procedures provided lower fusion rates than posterolateral fusion procedures. This may be due to a small sample size but the association with a minimally invasive technique warrants investigation. Due to the substantial difference in price between the OI and OC materials and the lack of evidence supporting higher fusion rates with more expensive OI agents, it is incumbent on the spine community to consider and reassess the products that are routinely used.