Implanted leads are critical for direct interfaces to the peripheral nervous system and have been used clinically since the 1960s. Even so, no open-architecture or open-source leads are available for autonomic nerve stimulation and recording. This is especially a problem for interfacing with soft, small diameter nerves measuring 1 mm or less. Since these are of great interest as targets in bioelectronic medicine, NEST 4 will introduce a new open-architecture nerve interface based on a helical cuff format. This cuff addresses the limitations of downscaling traditional materials and fabrication methods for polydimethylsiloxane-based cuffs and instead adopts a different scheme to achieve practical nerve cuffs using a composite Parylene C-PDMS structure. The CARSS helical microfabricated cuff uses soft polymers and thin film electrodes to achieve a miniaturized cuff form factor. The contra-rotational helical cuff design is achieved by post-processing the Parylene electrode array using a thermoforming process to achieve the final three-dimensional shape. The helical design is self- sizing and self-closing which avoids the need for sutures. The cuff is accompanied by a minimally invasive, custom endoscopic tool that will simplify surgery and allow access to deeper autonomic nerve branches. In NEST 4, the Parylene helical cuff will be developed, benchtop tested, and demonstrated with the surgical placement tool, paving the way for a widely accessible cuff for smaller nerves in clinical bioelectronic medicine research.