Enhancing Quality of Life After Partial Brachial Plexus Injury Combining Targeted Sensory Reinnervation and AI-Controlled User-Centered Prosthesis: A Case Study

Abstract

Background/Objectives: Upper limb amputation presents considerable physical and psychological challenges, especially in young, active individuals. This case study outlines the rehabilitation journey of a 33-year-old patient, an Italian national Paralympic snowboard cross athlete, who underwent elective transradial amputation followed by advanced surgical and prosthetic interventions. The objective was to assess the combined impact of upper limb Targeted Sensory Reinnervation (ulTSR) and the Adam’s Hand prosthetic system on functional recovery and user satisfaction. Methods: After a partial brachial plexus injury caused complete paralysis of his right hand, the patient opted for transradial amputation. He subsequently underwent ulTSR, performed by plastic surgeon, Alexander Gardetto, MD, which involved rerouting sensory nerves to defined regions of the residual limb in order to reestablish a phantom limb map. This reinnervation was designed to facilitate improved prosthetic integration. The Adam’s Hand, a myoelectric prosthesis with AI-based pattern recognition, was selected for its compatibility with TSR and intuitive control. Outcomes were evaluated using the OPUS questionnaire, the DASH, and patient feedback. Results: ulTSR successfully restored meaningful sensory input, allowing intuitive and precise control of the prosthesis, with minimal cognitive and muscular effort. The patient regained the ability to perform numerous activities of daily living such as dressing, eating, lifting, and fine motor tasks—which had been impossible for over 15 years. OPUS results demonstrated significant improvements in both function and satisfaction. Conclusions: This case highlights the synergistic benefits of combining ulTSR with user-centered prosthetic technology. Surgical neurorehabilitation, paired with advanced prosthetic design, led to marked improvements in autonomy, performance, and quality of life in a high-performance amputee athlete.

1. Introduction

Severe brachial plexus injuries represent some of the most debilitating forms of peripheral nerve trauma, often resulting in lifelong loss of function, chronic pain, and significant psychological burden. In cases where surgical nerve reconstruction fails to restore useful hand function, the affected limb may become more of a hindrance than a help. In such scenarios, elective amputation of the non-functional limb has emerged as a valid reconstructive strategy to improve autonomy and enable effective prosthetic use [1,2]. This case report presents a 33-year-old patient, an Italian national Paralympic snowboard cross athlete, who sustained a complex right brachial plexus injury following a high-energy motorcycle accident. Despite early nerve reconstruction, only partial recovery of elbow flexion and forearm sensation was achieved, while the hand remained completely paralyzed. After years of functional impairment, the decision was made to proceed with a transradial amputation, with the aim of enabling better prosthetic integration and performance in daily life and elite sport. Following amputation, the patient underwent upper limb Targeted Sensory Reinnervation (ulTSR), a procedure that reroutes residual sensory nerves to defined skin regions of the residual limb to facilitate the development of a phantom limb map and restore meaningful somatosensory feedback [3,4]. ulTSR not only enhances prosthesis embodiment but also has a documented effect on reducing phantom limb pain [4,5,6]. Crucial to the success of this approach was the fitting of an AI-controlled, user-centered prosthetic hand: the Adam’s Hand. Developed with a strong focus on intuitive usability, adaptability, and seamless integration with modern surgical techniques such as TSR, this prosthetic system leverages real-time electromyographic pattern recognition and inertial measurement data to enable proportional, natural control of multiple grip patterns. The hand requires minimal training, significantly reduces cognitive and muscular effort, and allows for the execution of a wide range of daily activities—particularly relevant for individuals aiming to regain independence. This case exemplifies the synergistic power of combining neuroplastic surgical approaches with intelligent prosthetic technologies to enhance functional outcomes and quality of life in high-performance users.

2. Material and Methods

2.1. User Presentation

Our patient is a 33-year-old, physically active man whose life changed dramatically following a severe motorcycle accident. Because of the trauma, he sustained a partial brachial plexus injury that resulted in complete paralysis of his right hand and a profound loss of motor function throughout the arm. The only remaining voluntary control in the affected limb was limited to the biceps and the deltoid muscle (Figure 1). He went through a long journey that led him, after careful clinical and personal evaluations, to take the difficult yet courageous decision to proceed with transradial amputation of the limb and ulTSR (

Table 1. Patient data.

Patient Data	Field
Age	33 y/o
Sex	Male
Type of injury	Partial Brachial Plexus Lesion right arm
Treatment	Elective Transradial Amputation and ulTSR
Vocation	National Paralympic Snowboard Cross Athlete

).

These events could have profoundly marked his life; however, he turned these challenges into motivation to achieve extraordinary goals: the Milan-Cortina 2026 Paralympics Winter Games (Figure 2).

“I have decided to take the most important decision of my life: I have amputated my hand. It was a very difficult choice, but an essential one for the improvement of my physical performance and for arriving especially at the Paralympics Winter Games Milan-Cortina at 100% of my potential.”

2.2. Surgical Intervention: Targeted Sensory Reinnervation

The decision to undergo limb amputation represents a major turning point in a patient’s life: the amputation of an upper limb engenders a multitude of physical and psychosocial challenges including alterations in body image and lifestyle, changes in self-concept, impairments in physical functioning, prosthesis use, and pain [7].

To overcome this obstacle, the patient underwent ulTSR, an advanced surgical technique performed by Alexander Gardetto, M.D. [3]. In cases of transradial amputation, ulTSR involves rerouting the sensory nerves that originally innervated the hand to specific regions of the residual limb. This targeted reconnection promotes the formation of a phantom limb map (PLM)—a cortical representation in which the brain continues to perceive the presence of the missing hand. By harnessing the brain’s neuroplastic potential, ulTSR re-establishes meaningful somatosensory input, reinforcing the illusion of hand presence and enabling the central nervous system to interpret tactile stimuli more coherently. As a result, it significantly improves the functional integration between the residual limb and advanced prosthetic systems, such as the Adam’s Hand.

Moreover, TSR has shown high efficacy in the management of phantom limb pain [3,8], one of the most challenging and debilitating complications following amputation.

“Thanks to the state-of-the-art surgery, I was able to regain sensitivity; in addition, very strong signals coming from the forearm muscles allow me to move a myoelectric hand.”

2.3. Choice of the Prosthetic Device: The Adam’s Hand

Following the surgical intervention and the initial stages of rehabilitation, it became essential to identify a prosthetic device capable of satisfying the patient’s functional, sensory, and psychological needs. The choice of Adam’s Hand was guided by several key features behind its concept. First, a patented mechanism allows the digits to automatically adapt to the shape and size of the objects and automatically readjust if the object moves inside the grip [9,10]. This mechanism provides both high robustness and highly natural, human-like appearance. Moreover, the Adam’s Hand is provided with a proprietary AI Pattern Recognition control algorithm, which makes this hand prosthesis intuitive, easy to use, and compatible with advanced surgical approaches such as Targeted Sensory Reinnervation.

The Adam’s Hand was specifically designed to provide a natural, intuitive user experience, meeting the needs of individuals who require a prosthesis that feels like a true extension of their body. To ensure an optimal fit with the user’s muscle tone, the Adam’s Hand AI algorithm requires a quick and simple calibration procedure, during which EMG signals related to rest, wrist flexion (close hand) and wrist extension (open hand) muscle contractions are recorded. Once calibrated, the system enables proportional control and different control strategies. Despite the presence of slight crosstalk, the calibration algorithm allows the patient precise and natural management of hand movements.

“When I tried Adam’s Hand for the first time, it was something incredible, perhaps one of the strongest emotions of my life. To be able to move a hand after 15 years is something magical.”

Additionally, thanks to an inertial measurement unit (IMU), and an advanced motion tracking algorithm, users can access different grip patterns simply by changing the position of the thumb and the hand in the space. By eliminating the need for complex muscle contraction sequences, such as double or triple pulses or co-contractions, long open, etc., the prosthesis becomes more intuitive and easier to use. The Adam’s Hand is the result of a User-Centered Design approach, combining clinical insights with user feedback to create a prosthetic device that improves the user experience.

3. Results

3.1. Clinical Results

Our patient was the world’s first user of a myoelectric, multi-articulating hand prosthesis, with Partial Brachial Plexus Injury, who underwent ulTSR after elective amputation. After three months of recovery from surgery, he reported significant improvements in motor function of the right limb, including regained triceps activation, enhanced shoulder mobility and the ability to perform smooth, controlled movements involving the entire arm. Along with improved joint coordination at shoulder level, the patient also reported increased control of biceps contraction.

Since the prosthesis’s delivery, he has regained full use of the right arm musculature, leading to a total reintegration of the right limb into daily activities.

“In daily life, I’ve gone back to using the Adam’s Hand as if it were my natural one, supporting my left limb to grab, grasp, lift, pull, and so on. In short, it’s truly a return to my origins”

3.2. OPUS and DASH Results

The effectiveness of the combination of ulTSR and the Adam’s Hand was assessed by administering the Upper Extremity Functional Status (UEFS) section of the Orthotics and Prosthetics User’s Survey (OPUS) [11] as well as the Disability of the Arm, Shoulder and Hand (DASH) Outcome Measure [12]. These outcome measures were administered at the 6th and 18th month following prosthesis delivery. The scores collected, summarized in

Table 2. Summary of OPUS and DASH scores at 6th and 18th month post-delivery of the prosthesis.

Time Since Delivery	OPUS Raw Score	OPUS Rasch Measures *	OPUS Standard Error	DASH Raw Score	DASH Dis/Sym Score
6 months	30	40.40	1.92	75	37.50
18 months	68	56.45	2.21	48	15.00

* Rasch Measures are calculated using the Table 20.1 provided with the OPUS Upper Extremity Scoring Guide [13].

, were calculated and converted using the guide provided by the Shirley Ryan Ability Lab website [13] and DASH Outcome Measure Scoring Manual [14]. These highlighted a significant improvement in the patient’s ability to perform daily tasks, many of which he had been unable to accomplish independently for 15 years (Table 2).

Among the activities reported as particularly easy with Adam’s Hand are pulling up a zipper, drinking from a cup, using a fork or spoon, cutting meat with a fork and knife, pouring from a can, lifting a laundry basket, opening a bag of chips, unscrewing a bottle cap, and retrieving banknotes from a wallet (Figure 3a,b).

Upper limb Targeted Sensory Reinnervation, and the Adam’s Hand intuitive grip selection algorithm, enhance the reliability of the prosthetic system, ultimately increasing user satisfaction and acceptance of the prosthetic hand [3]. This contributes to the goal of reducing the rejection rate, a critical challenge in the upper limb prosthetic industry [15]. This simplicity translates into a drastically increased ease of use, significantly reducing muscle fatigue and cognitive load. Thanks to only precision, power and lateral grips, users can perform up to 80% of activities of daily living (ADLs) [16,17], accelerating the learning curve and enhancing confidence in real-life applications.

4. Discussion

This case underlines the clinical value of ulTSR in the context of elective amputation for partial brachial plexus injury, followed by the adoption of a user-centered, AI-driven hand prosthesis. In this class of injuries, a combined approach of amputation, nerve rerouting, and prosthetic rehabilitation can restore meaningful hand function and utility [18]. In the reported case study, rerouting residual sensory nerves reestablished a PLM in the patient’s arm, effectively restoring sensory input from the missing hand.

Notably, this ulTSR technique creates a biological neural interface that operates without the need for implanted electrodes or magnets [19,20,21,22]. By utilizing the body’s existing neural pathways and rerouting residual sensory nerves to reinnervate forearm skin, this approach avoids the complications associated with foreign body implantation, such as device dislocation, migration, granuloma formation, and scarring that could potentially damage surrounding nerves or muscles [23]. This biological reconstruction maintains the integrity of the natural sensorimotor system while providing a stable platform for sensory feedback.

Providing real and genuine feedback is one of the most long-standing challenges in prosthetics: traditional feedback systems often feel artificial and unnatural [3]. In contrast ulTSR can lead to higher acceptance of the upper limb prosthesis since restored hand sensations allow the brain to interpret them as arising from the missing hand, contributing to a more natural and embodied user experience. The reinnervated skin areas serve as natural receptors for various types of sensory feedback modalities. Vibrotactile stimulation can be applied through small actuators that convert pressure or touch sensations from prosthetic sensors into mechanical vibrations felt on the reinnervated skin. Alternatively, electrical stimulation can provide precise, controllable sensory input through surface electrodes, while pneumatic systems can deliver tactile feedback through controlled air pressure changes. Each modality offers distinct advantages in terms of sensation quality, power consumption, and integration complexity with prosthetic devices.

The incorporation of AI-driven myoelectric control strategies in a prosthesis builds upon a broader trend toward more intuitive, multifunctional upper-limb prostheses. Recent myoelectric control approaches increasingly utilize machine learning algorithms for pattern recognition to interpret user’s EMG signals, enabling more natural and seamless control of multiple degrees of freedom compared to traditional dual-site or trigger-based methods [24]. Pattern recognition for myoelectric control, as employed in the Adam’s Hand, has been lauded by users for its intuitiveness and fast learning, reducing mental effort required to operate complex hands [24].

The world of upper limb prosthesis control approaches is moving toward adaptive and intelligent prosthetic control systems that continuously self-correct and adjust to the user. Several studies already show that combining EMG inputs with additional sensor data (e.g., inertial measurement units for motion context) could enhance control robustness and intuitiveness [25,26]. This hints at an exciting future where a prosthetic hand can predict and anticipate user intention in real time.

The Adam’s Hand is equipped with several features that aim to decrease the challenge of prosthesis control. In fact, the Adam’s Hand is provided with its proprietary underactuated mechanism that allows the fingers to automatically adapt to the shape and size of the objects [9,10]. In addition, the real-time AI pattern recognition algorithm allows the Adam’s Hand to automatically adapt to the user’s muscle contraction by using two EMG sensors. Lastly, the AI grip selection algorithm takes into account the position of the thumb, and the position of the hand in space, to make the Adam’s Hand able to autonomously determine the most likely activity the user would like to perform. It automatically selects the most appropriate grip to carry out this activity. These three user-centered design principles, behind the Adam’s Hand development, make the several grips of other multi-articulating hands to be no longer needed. Dual site grip selection control strategies, such as double pulses, triple pulses, co-contractions, and other muscle triggers are often perceived as time-consuming and cognitively demanding [24],

Auser-centered philosophy prioritizes the needs, preferences and experiences of the user at every stage, from surgical planning, to device training and everyday use [27,28,29,30]. Involving users in the design process, and incorporating their feedback, helps ensure that final products are technically effective and well-accepted in real world use [29,30,31].

Crucially, ulTSR and technological advancements integrated into the Adam’s Hand need to translate into improved functional outcomes and long-term user adaptation. The evolution of the patient’s interaction with the prosthesis is quantitatively reflected in his outcome measure scores over time. Significant improvements in the OPUS and DASH scores were observed between the 6th and the 18th month after prosthesis delivery. The 6th month DASH indicated a score of 37.5% of perceived disability in arm function while OPUS score was 40.40 (Rasch measure). By the 18th month, the OPUS score had increased to 56.45 (Rasch measure), indicating a higher level of perceived ability, and the DASH score had fallen to only 15%. This substantial change over a year’s time demonstrated that the patient did not plateau after the first few months of prosthetic use, rather he continued to gain proficiency, strength and confidence using his prosthesis. Activities that were difficult or done with hesitation at 6 months became easy and routine by 18 months. These results highlight not only the device’s ease of use but also the significant impact on the patient’s quality of life. After more than a decade of relying on his left hand, he has regained the ability to proficiently use his right hand as well.

From a practical standpoint, the synergy between ulTSR and the adoption of the Adam’s Hand translated into rapid and substantial improvements in the patient’s daily life. Within months of the amputation and reinnervation surgery, and after fitting the prosthesis, he progressed from total dependence on his left arm to performing bimanual tasks easily. The combination of the surgery, and the Adam’s Hand mechanical and AI-driven design, enabled a level of autonomy and performance akin to having a functional sound limb. On the myoelectric control side, real time pattern recognition, combined with IMU-based contextual awareness, reduced mode switching and cognitive load, enabling reliable multi-grip use during activities of daily living (ADLs). The AI-driven decoding of surface EMGs provided proportional, natural control across everyday activities. This improved robustness to signal variability and supported consistent performance both at home and workplace.

The biological neural interface, created through ulTSR, seamlessly integrates with modern prosthetic technology. This eliminates the need for complex implantable systems, while maintaining sophisticated sensory feedback capabilities, essential for natural prosthetic control. This approach represents a paradigm shift toward more biocompatible and sustainable solutions in prosthetic rehabilitation.

In conclusion, this case highlights that surgical nerve rerouting, and user-centered prosthetic design, should be considered as complementary facets of a single rehabilitative strategy. As demonstrated by the results of the OPUS UEFS and DASH Outcome Measure scores, this surgical-technological synergy results in valuable outcomes. The implication for the future could be substantial: a multidisciplinary approach in which surgical and technological solutions work together to maximize long-term adaptation and significantly enhance the quality of life for patients with complex injuries. Within this framework, modern myoelectric systems that leverage AI-driven control and multisensory inputs, such as the Adam’s Hand, can translate residual muscle activity into proportional, context-aware movements. This reduces cognitive load and enhances reliability in daily use. In parallel, machine learning models, developed through a user-centered design approach, further support user adaptation and prosthetic control. This results in promoting better device acceptance and sustained functional performance. Furthermore, the biological neural interface approach, through ulTSR, offers long-term stability and reduces the risk of device-related complications which often necessitate revision surgeries in traditional implantable neural interface systems. This combination of biological reconstruction, with advanced prosthetic technology, represents a promising direction for achieving more natural and durable neural interfaces in prosthetic rehabilitation. To further validate this approach, an international multicenter study is currently being prepared, in which a large cohort of patients will be evaluated over a three-year period. This effort aims to generate robust clinical evidence, and ultimately establish ulTSR as a standard technique, for patients with partial brachial plexus injury.