An Open-Source 3D-Printed Hindlimb Stabilization Apparatus for Reliable Measurement of Stimulation-Evoked Ankle Flexion in Rat.

Currently there are numerous methods to evaluate peripheral nerve stimulation interfaces in rats, with stimulation-evoked ankle torque being one of the most prominent. Commercial rat ankle torque measurement systems and custom one-off solutions have been published in the literature. However, commercial systems are proprietary and costly and do not allow for customization. One-off lab-built systems have required specialized machining expertise, and building plans have previously not been made easily accessible. Here, detailed building plans are provided for a low-cost, open-source, and basic ankle torque measurement system from which additional customization can be made. A hindlimb stabilization apparatus was developed to secure and stabilize a rat's hindlimb, while allowing for simultaneous ankle-isometric torque and lower limb muscle electromyography (EMG). The design was composed mainly of adjustable 3D-printed components to accommodate anatomical differences between rat hindlimbs. Additionally, construction and calibration procedures of the rat hindlimb stabilization apparatus were demonstrated in this study. In vivo torque measurements were reliably acquired and corresponded to increasing stimulation amplitudes. Furthermore, implanted leads used for intramuscular EMG recordings complemented torque measurements and were used as an additional functional measurement in evaluating the performance of a peripheral nerve stimulation interface. In conclusion, an open-source and noninvasive platform, made primarily with 3D-printed components, was constructed for reliable data acquisition of evoked motor activity in rat models. The purpose of this apparatus is to provide researchers a versatile system with adjustable components that can be tailored to meet user-defined experimental requirements when evaluating motor function of the rat hindlimbs.

Characterization of a Temporary Peripheral Nerve Stimulation Electrode Utilizing a Bioabsorbable Suture Substrate.

Electrical stimulation after peripheral nerve injury (PNI) has the potential to promote more rapid and complete recovery of damaged fiber tracts. While permanently implanted devices are commonly used to treat chronic or persistent conditions, they are not ideal solutions for transient medical therapies due to high costs, increased risk of surgical injury, irritation, infection, and persistent inflammation at the site of the implant. Furthermore, removal of temporary leads placed on or around peripheral nerves may have unacceptable risk for nerve injury, which is counterproductive in developing therapies for PNI treatment. Transient devices which provide effective clinical stimulation while being capable of harmless bioabsorption may overcome key challenges in these areas. However, current bioabsorbable devices are limited in their robustness and require complex fabrication strategies and novel materials which may complicate their clinical translation pathway. In this study, we present a simple bioabsorbable / biodegradable electrode fabricated by modifying standard absorbable sutures, and we present data characterizing our prototype's stability in vitro and in vivo.