The principal investigator, Swen Groen, a biomedical engineer from McGill University, highlighted that the device was meticulously designed with an emphasis on both precision and ease of use for surgeons. Its compact and flexible design allows for seamless integration into existing surgical workflows while offering real-time manual control, which is crucial in such a limited work environment typically found during vocal cord surgeries. This precision is paramount; not only does it enhance the accuracy of the hydrogel application, but it also allows surgeons to maintain clarity in viewing the vocal folds.

Voice disorders, which affect between 3% and 9% of individuals throughout their lives, often stem from the presence of cysts, growths, or cancers on the vocal cords. Surgical removal of these growths is common, but a frequent consequence is the development of fibrosis—a condition that leads to the stiffening of vocal cords and difficulties speaking. To combat this, surgeons generally resort to injecting hydrogels into the surrounding throat tissues. However, the complexity of accurately delivering these hydrogels via traditional injection methods has presented persistent challenges, which the new bioprinting technology aims to overcome.

To enhance hydrogel delivery, the research team embarked on the ambitious task of designing a miniature 3D printer suitable for use during vocal cord surgeries. Previous attempts at creating bioprinting devices have largely targeted applications in larger organs like the colon and liver, with many of these options being too cumbersome for the intricate environment of vocal cord procedures. Acceptance of a suitable printhead size that could navigate the oral cavity and be manipulated without obstructing the surgeon’s line of sight was an intense focus during the design stage.

The innovative design mimics the functionality of an elephant’s trunk. The robot’s printhead features a nozzle at the end of a flexible structure, which is controlled by tendon-like cables connecting to a control module. This module can be mounted on standard surgical microscopes, allowing for precision control during the operation. As the device operates, it precisely delivers a hyaluronic acid-based hydrogel in fine lines measuring 1.2 mm, enabling a controlled and targeted application that resembles the natural architecture of the vocal folds.

In testing phases, researchers showcased the bioprinter’s capabilities by manually controlling it to “draw” shapes such as spirals, hearts, and letters on flat surfaces, demonstrating its high degree of accuracy. Furthermore, the bioprinter was employed in delivering hydrogels to simulacra of vocal folds used for surgical training. Remarkably, the device successfully reconstructed complex vocal fold geometries, addressing specific tissue defects like those caused by lesion removals or complete vocal fold reconstructions.

One compelling aspect of this development is the reliable predictability of the device’s movements, even given its flexibility—a fact noted by coauthor Audrey Sedal. Sedal drew a comparison between the bioprinter and a typical garden hose, highlighting that unlike the erratic behavior seen in many tubes under pressure, this device maintains a consistent and controlled flow.

While the current version of the device is controlled manually, advances are underway to develop a hybrid system that blends both autonomous and manual functionalities. By refining the precision and reliability of the bioprinter, the research team aims to facilitate a more clinical application of this technology.

The next critical milestone for this project involves transitioning from laboratory settings to animal testing, a critical step that aims to gather evidence on the bioprinter’s efficacy and safety. Successful outcomes in preclinical trials would pave the way for human clinical trials, where the ultimate objective is to assess the device’s usability, accuracy in hydrogel application, and the resultant clinical outcomes relative to current treatment methodologies.

Research development of this nature embodies a transformative step forward in surgical practices concerning vocal health and rehabilitation. By leveraging innovative technologies such as 3D printing combined with advanced biomaterials, medical professionals are better equipped to address the complexities associated with post-surgical complications, ultimately enhancing patient recovery experiences and speech functionalities.

In summary, the intersection of engineering and medicine evidenced through this research heralds a promising future for patients facing the challenges of voice disorders. As these technologies evolve and clinical trials loom on the horizon, hopes are high for a new era of interventions that could

The exosuit, an impressive integration of lightweight fabric-based pneumatic actuators, works in harmony with inertial sensors to deliver unparalleled assistance in both shoulder abduction and elbow flexion or extension movements. This innovative design marks a significant departure from previous exoskeletons, which often prioritize single joint movements. By utilizing advanced soft robotics technology, the developers aim to create an assistive device that not only enhances muscle function but also fits comfortably into the lives of those with limited mobility.

Initial validation of the individual elbow modules of the exosuit involved 11 healthy volunteers. These early testing phases were instrumental in refining the technology, ensuring that it would provide optimal support for targeted muscle groups while being lightweight and easy to operate. Following this initial validation, the complete exosuit, incorporating both shoulder and elbow assistive modules, was subsequently evaluated in a clinical setting involving 15 individuals diagnosed with cervical spinal cord injuries, categorized from motor incomplete to complete injuries (AIS A–D).

Results from the study painted an encouraging picture: participants with SCI experienced a remarkable improvement in their functional performance. Specifically, the support provided by the exosuit resulted in more than a 250% increase in static endurance time. This gain is particularly significant as it suggests that individuals can maintain positions and perform tasks that require prolonged muscle engagement without excessive fatigue. Moreover, the use of the exosuit was associated with up to a 50% reduction in the activity of primary muscles during dynamic tasks, indicating that the device effectively offloads some of the work from the user, allowing for easier movement.

Additionally, within the cohort of SCI participants, two individuals who retained prehensile capabilities observed meaningful enhancements in their performance on the box and block test—a common measure of upper extremity functionality and dexterity. With the exosuit’s assistance, these individuals demonstrated superior agility and proficiency in transferring blocks, highlighting the device’s potential to augment fine motor skills as well as general upper limb movement.

Complex control systems are usually a major limitation in robotics, especially where real-time adjustments are crucial for seamless user experience. The authors emphasize that their approach, which leverages inertial sensors, allows for adaptive and responsive actuation, maintaining a natural feel to the movements. This soft actuation mechanism ensures that the suit not only adheres to the user’s movements but also responds dynamically to inter-joint motions, simulating natural biomechanics more effectively than rigid exoskeleton solutions.

Participant feedback played an integral role in assessing the success of the exosuit. Users expressed that the soft and adaptive nature of the actuation provided a comfortable fit and ease of use, which contrasts sharply with traditional, bulky robotic systems that often encumber users rather than assist them. Such positive reception among participants speaks volumes about the device’s design philosophy, which prioritizes user-centered care in the development of assistive technologies.

Looking ahead, the implications of this research are substantial. The enhancements in endurance and decreased muscle strain could lead not only to improved physical capabilities but also to enhanced psychological well-being for individuals in the SCI community. Empowering individuals to perform daily tasks with greater ease can foster a sense of independence, potentially translating these physical advantages into improved quality of life.

The researchers affirm that the modularity of their exosuit provides a versatile platform that can be adapted for further applications in rehabilitation beyond the scope of this study. Given that it operates through pneumatic actuation, future iterations could see expanded functionalities, such as support for additional joint movements or even integration with digital health monitoring systems to track usage and progress over time.

However, as with any groundbreaking technology, ongoing research will be necessary to identify long-term outcomes and to refine functionality. Future studies will look to include larger cohorts and possibly longer durations of exosuit usage to fully explore the potential of this innovative rehabilitation solution.

In conclusion, this soft exosuit represents a significant leap forward in the quest to restore limb function for individuals living with spinal cord injuries. By focusing on multiple joints and employing a soft and modular design, it addresses some of the key limitations of existing assistive technologies. The potential of this research to facilitate improved functional independence and enriched lifestyles for the SCI community cannot be overstated, marking a promising horizon for neurorehabilitative advancements.

Subject of Research: Improvements in shoulder and elbow motor functions using a soft exosuit for individuals with spinal cord injuries.

Article Title: A multi-joint soft exosuit improves shoulder and elbow motor functions in individuals with spinal cord injury.

Article References:

Ferroni, R., D’Avola, G., Sciarrone, G. et al. A multi-joint soft exosuit improves shoulder and elbow motor functions in individuals with spinal cord injury.
Nat Mach Intell 7, 1390–1402 (2025). https://doi.org/10.1038/s42256-025-01105-8

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s42256-025-01105-8

Keywords: Spinal Cord Injury, Soft Exosuit, Rehabilitation Technology, Upper Limb Function, Pneumatic Actuators, Modularity, Assistive Devices, Neuromuscular Control, Dynamic Tasks, Functional Independence.