Over the last few decades there has been a push to enhance the use of advanced prosthetics within the fields of biomedical engineering, neuroscience, and surgery. Through the development of peripheral neural interfaces and invasive electrodes, an individual's own nervous system can be used to control a prosthesis. With novel improvements in neural recording and signal decoding, this intimate communication has paved the way for bidirectional and intuitive control of prostheses. While various collaborations between engineers and surgeons have led to considerable success with motor control and pain management, it has been significantly more challenging to restore sensation. Many of the existing peripheral neural interfaces have demonstrated success in one of these modalities; however, none are currently able to fully restore limb function. Though this is in part due to the complexity of the human somatosensory system and stability of bioelectronics, the fragmentary and as-yet uncoordinated nature of the neuroprosthetic industry further complicates this advancement. In this review, we provide a comprehensive overview of the current field of neuroprosthetics and explore potential strategies to address its unique challenges. These include exploration of electrodes, surgical techniques, control methods, and prosthetic technology. Additionally, we propose a new approach to optimizing prosthetic limb function and facilitating clinical application by capitalizing on available resources. It is incumbent upon academia and industry to encourage collaboration and utilization of different peripheral neural interfaces in combination with each other to create versatile limbs that not only improve function but quality of life. Despite the rapidly evolving technology, if the field continues to work in divided “silos,” we will delay achieving the critical, valuable outcome: creating a prosthetic limb that is right for the patient and positively affects their life.

Background Extrinsic factors like smoking, alcohol use, and sun exposure have been shown to accelerate facial aging. There is evidence that changes to the midface and lower third of the face in isolation contribute significantly to one’s perception of overall facial age. With data suggesting that facial coverings are effective against the spread of the respiratory virus COVID-19, mask wearing has become commonplace. To date, there have been no studies that explore how covering the lower third of the face impacts an observer’s perception of age. Objectives We hypothesize that covering the lower third of the face with a mask will make a person appear younger. Methods One hundred consecutive plastic surgery patients were photographed in a standardized fashion, both masked and unmasked. A questionnaire for factors known to contribute to facial aging was administered. These photographs were randomized to 6 judges who estimated the patients’ age and also quantified facial rhytids with the validated Lemperle wrinkle assessment score6. Data were analyzed using PROC MIXED analysis. Results Masked patients on average appeared 6.17% younger (mean difference = 3.16 years, 95% CI = 2.26-4.06, P < 0.0001). Wrinkle assessment scores were 9.81% lower in the masked group (mean difference = 0.21, 95% CI = 0.10-0.32, P = 0.0003). All subgroups appeared younger in a mask except for patients aged 18-40 years chronological age (P = 0.0617) and patients BMI>35 (P = 0.5084). Conclusions The mask group appeared younger and had lower overall and visible wrinkle assessment scores when compared to the unmasked group. This has implications for our understanding of the contributions of the lower third of the face to overall perceived facial age.

As technology continues to improve within the neuroprosthetic landscape, there has been a paradigm shift in the approach to amputation and surgical implementation of haptic neural prosthesis for limb restoration. The Osseointegrated Neural Interface (ONI) is a proposed solution involving the transposition of terminal nerves into the medullary canal of long bones. This design combines concepts of neuroma formation and prevention with osseointegration to provide a stable environment for conduction of neural signals for sophisticated prosthetic control. While this concept has previously been explored in animal models, it has yet to be explored in humans. This anatomic study used three upper limb and three lower limb cadavers to assess the clinical feasibility of creating an ONI in humans. Anatomical measurement of the major peripheral nerves- circumference, length, and depth- were performed as they are critical for electrode design and rerouting of the nerves into the long bones. CT imaging was used for morphologic bone evaluation and virtual implantation of two osseointegrated implants were performed to assess the amount of residual medullary space available for housing the neural interfacing hardware. Use of a small stem osseointegrated implant was found to reduce bone removal and provide more intramedullary space than a traditional implant; however, the higher the amputation site, the less medullary space was available regardless of implant type. Thus the stability of the endoprosthesis must be maximized while still maintaining enough residual space for the interface components. The results from this study provide an anatomic basis required for establishing a clinically applicable ONI in humans. They may serve as a guide for surgical implementation of an osseointegrated endoprosthesis with intramedullary electrodes for prosthetic control.

Volume 149, Number 1 • Letters 151e to reconnect with a world they once knew with a restored sense of self and improved quality of life. As osseointegration and advanced neural interfacing continue to grow in popularity, there is a pressing need for comparable and repeatable research that includes structured rehabilitation programs with sophisticated monitoring.