Paul S Cederna

• MD
• Professor at University of Michigan

The development of neuroprosthetic limbs—robotic devices designed to restore lost limb functions for individuals with limb loss or impairment—has made significant strides over the past decade, reaching the stage of successful human clinical trials. A current research focus involves providing somatosensory feedback to these devices, which was shown...

Upper limb loss can negatively impact an individual’s ability to perform daily tasks as well as mental health and well-being. Currently available prosthetic control interfaces provide limited prosthetic finger dexterity compared to the complex functions that multi-articulating robotic hands are capable of actuating. A significant barrier is the abi...

Objective The objective was to assess the postsurgical outcomes of regenerative peripheral nerve interface (RPNI) surgery in a prospective cohort of major lower extremity amputation patients with chronic postamputation pain. Background Chronic pain in lower limb amputation patients is commonly the result of neuroma formation after traumatic periph...

Individuals who use upper limb prostheses receive limited feedback from their devices. Researchers have attempted to elicit sensation through direct stimulation of peripheral nerves or through stimulation of reinnervated skin or muscle. Previous research found that electrical stimulation of Regenerative Peripheral Nerve Interfaces (RPNIs) elicited...

This chapter describes the use of the regenerative peripheral nerve interface (RPNI) as a physiologic solution to treat neuroma pain. The RPNI consists of a free autologous skeletal muscle graft secured around the terminal end of a peripheral nerve. Through numerous animal and human studies, RPNIs have been shown to enable synaptogenesis between th...

Innovations in the fields of prosthetic devices and neuroprosthetic control strategies have opened new frontiers for optimizing functional restoration for people suffering from limb loss. Commercial prosthetic devices are now available with sophisticated electrical and mechanical components that can closely replicate the functions of the human musc...

Volumetric muscle loss (VML) is a clinical state that results in impaired skeletal muscle function. Engineered skeletal muscle can serve as a treatment for VML. Currently, large biopsies are required to achieve the cells necessary for the fabrication of engineered muscle, leading to donor-site morbidity. Amplification of cell numbers using cell pas...

Background The coronavirus disease 2019 (COVID-19) pandemic required an unprecedented transformation of medical education, shifting from traditional, in-person learning to distanced, online learning. This study aimed to review changes to medical education and describe the advantages and disadvantages of virtual medical education experienced by medi...

Objective To evaluate the prophylactic effect of Regenerative Peripheral Nerve Interface (RPNI) surgery on pediatric post-amputation pain. Summary of Background Data Chronic post-amputation pain is a debilitating and refractory sequela of limb amputation affecting up to 83% of pediatric patients with limb loss, resulting in disability and decrease...

Complications following amputation can be devastating for patients, including debilitating neuropathic pain, the inability to perform activities of daily living (ADLs) or gain meaningful employment. While prosthesis use allows patients to restore independence and reintegrate into daily activities, patients often abandon these devices. Despite the i...

Background A neuroma occurs when a regenerating transected peripheral nerve has no distal target to reinnervate. Symptomatic neuromas are a common cause of postamputation pain that can lead to substantial disability 1–3 . Regenerative peripheral nerve interface (RPNI) surgery may benefit patients through the use of free nonvascularized muscle graft...

Limb amputations can be devastating and significantly affect an individual's independence, leading to functional and psychosocial challenges in nearly 2 million people in the United States alone. Over the past decade, robotic devices driven by neural signals such as neuroprostheses have shown great potential to restore the lost function of limbs, a...

In 1964, the Section of Plastic and Reconstructive Surgery at the University of Michigan opened its doors to future surgeons and leaders in the field. Today, we are celebrating the 60-year history of the program and its significant contributions to the field. Beginning under the leadership of Reed O. Dingman, MD, DDS, the program began with three f...

Individuals with upper limb loss lack sensation of the missing hand, which can negatively impact their daily function. Several groups have attempted to restore this sensation through electrical stimulation of residual nerves. The purpose of this study was to explore the utility of regenerative peripheral nerve interfaces (RPNIs) in eliciting referr...

Background Opioid misuse after surgery remains a public health crisis in the United States. Recent efforts have focused on tracking pain medication use in surgical populations. However, accurate interpretations of medication use remain quite challenging given inconsistent usage of different datasets. The purpose of this study was to investigate the...

Innovations in the fields of prosthetic devices and neuroprosthetic control strategies have opened new frontiers for the treatment and rehabilitation of individuals undergoing amputation. Commercial prosthetic devices are now available with sophisticated electrical and mechanical components that can closely replicate the functions of the human musc...

Scleroderma is a chronic connective tissue disease characterized by inflammation, vascular injury, and progressive skin fibrosis, resulting in significant aesthetic and functional impairments for patients. Current therapies are limited and insufficiently treat the cutaneous manifestations of scleroderma. Autologous fat transfer (AFT) is a surgical...

p>In four participants with upper limb loss, we characterized the quality and location of sensation elicited through electrical stimulation of regenerative peripheral nerve interfaces (RPNIs) over time (up to 54 months post implantation of wires). We also measured sensory perception and discomfort thresholds, sensitivity to changes in stimulation a...

p>In four participants with upper limb loss, we characterized the quality and location of sensation elicited through electrical stimulation of regenerative peripheral nerve interfaces (RPNIs) over time (up to 54 months post implantation of wires). We also measured sensory perception and discomfort thresholds, sensitivity to changes in stimulation a...

Regenerative peripheral nerve interface (RPNI) surgery has been demonstrated to be an effective tool as an interface for neuroprosthetics. Additionally, it has been shown to be a reproducible and reliable strategy for the active treatment and for prevention of neuromas. The purpose of this article is to provide a comprehensive review of RPNI surger...

Background: Treating neuroma pain is a clinical challenge. Identification of sex-specific nociceptive pathways allows a more individualized pain management. The Regenerative Peripheral Nerve Interface (RPNI) consists of a neurotized autologous free muscle using a severed peripheral nerve to provide physiological targets for the regenerating axons....

The scientific study of facial aging has transformed modern facial rejuvenation. As we age, fat loss in specific fat compartments is a major contributor to the structural aging of the face. Autologous fat grafting is safe, abundant, readily available, and completely biocompatible, which makes it the preferred soft tissue filler in the correction of...

Objective. Extracting signals directly from the motor system poses challenges in obtaining both high amplitude and sustainable signals for upper-limb neuroprosthetic control. To translate neural interfaces into the clinical space, these interfaces must provide consistent signals and prosthetic performance. Approach. Previously, we have demonstrated...

Background: The armamentarium of a plastic surgeon is vast, consisting of an array of surgical procedures from head to toe. Unfortunately, plastic surgeons have been losing portions of their operative domain to other surgical subspecialties for years. The number of subspecialties invading our niche is bothersome, but more concerning is the fact th...

Stiff skin syndrome (SSS) is a rare cutaneous disorder characterized by cutaneous fibrosis resulting in the early onset of thickened and indurated skin, joint mobility restrictions, and contractures. We describe a father and son with familial SSS who presented with bilateral exertional pain and a confirmed diagnosis of chronic exertional compartmen...

Replacing human hand function with prostheses goes far beyond only recreating muscle movement with feedforward motor control. Natural sensory feedback is pivotal for fine dexterous control and finding both engineering and surgical solutions to replace this complex biological function is imperative to achieve prosthetic hand function that matches th...

Objective To describe the ultrasound (US) appearance of regenerative peripheral nerve interfaces (RPNIs) in humans, and correlate clinically and with histologic findings from rat RPNI.Materials and methodsPatients (≥ 18 years) who had undergone RPNI surgery within our institution between the dates of 3/2018 and 9/2019 were reviewed. A total of 21 p...

Background: Without meaningful, intuitive sensory feedback, even the most advanced myoelectric devices require significant cognitive demand to control. The Dermal Sensory Regenerative Peripheral Nerve Interface (DS-RPNI) is a biologic interface designed to establish high-fidelity sensory feedback from prosthetic limbs. Methods: DS-RPNIs are cons...

Objective. Advanced myoelectric hands enable users to select from multiple functional grasps. Current methods for controlling these hands are unintuitive and require frequent recalibration. This case study assessed the performance of tasks involving grasp selection, object interaction, and dynamic postural changes using intramuscular electrodes wit...

Currently available prosthetic hands are capable of actuating anywhere from five to 30 degrees of freedom. However, grasp control of these devices remains unintuitive and cumbersome. To address this issue, we propose directly extracting finger commands from the neuromuscular system. Two persons with transradial amputations had bipolar electrodes im...

Despite advancements in surgical and rehabilitation strategies, extremity amputations are frequently associated with disability, phantom limb sensations, and chronic pain. Investigation into potential treatment modalities has focused on the pathophysiological changes in both the peripheral and central nervous systems to better understand the underl...

Despite significant advancements in neuroprosthetic control strategies, current peripheral nerve interfacing techniques are limited in their ability to facilitate accurate and reliable long-term control. The regenerative peripheral nerve interface (RPNI) is a biologically stable bioamplifier of efferent motor action potentials with demonstrated lon...

Current prosthetic limbs offer little to no sensory feedback. Developments in peripheral nerve interfaces provide opportunities to restore some level of tactile feedback that is referred to the prosthetic limb. One such method is a Regenerative Peripheral Nerve Interface (RPNI), composed of a muscle graft wrapped around a free nerve ending. Here, w...

Sensory afferent fibers are an important component of motor nerves and compose the majority of axons in many nerves traditionally thought of as “pure” motor nerves. These sensory afferent fibers innervate special sensory end organs in muscle, including muscle spindles that respond to changes in muscle length and Golgi tendons that detect muscle ten...

Regenerative Peripheral Nerve Interface represents a surgical technique, whereby a free muscle graft is utilized as a physiological ‘target’ for peripheral nerve ingrowth. This procedure was first developed for increasing the amplitude of motor nerve signals to control neuro-prosthetic devices. Regenerative Peripheral Nerve Interface has since been...

Extracting motor signals directly from the peripheral nervous system poses challenges in obtaining both high amplitude and sustainable signals for upper-limb neuroprosthetic control. To translate peripheral nerve interfaces into the clinical space, these interfaces must provide consistent signals and prosthetic performance. Previously, we have demo...

Without meaningful and intuitive sensory feedback, even the most advanced prosthetic limbs remain insensate and impose an enormous cognitive burden during use. The regenerative peripheral nerve interface can serve as a novel bidirectional motor and sensory neuroprosthetic interface. In previous human studies, regenerative peripheral nerve interface...

Autologous fat grafting (AFG) has traditionally been used for facial rejuvenation and soft tissue augmentation, but in recent years, its use has expanded to treat diseases of the hand. Autologous fat grafting is ideal for use in the hand because it is minimally invasive, can restore volume, and has regenerative capabilities. This review summarizes...

Neonatal brachial plexus injuries may cause critical limitations of upper extremity function. The optimal surgical approach to address neonatal brachial plexus injuries has not been defined. In this systematic review, we compare clinical results after spinal accessory to suprascapular nerve transfer and nerve graft techniques among patients with ne...

Tissue engineering methodologies have the potential to treat volumetric muscle loss via the growth of exogenous skeletal muscle grafts from small autogenous muscle biopsies. A significant obstacle preventing the widespread use of engineered skeletal muscle grafts in a clinical setting is the high number of skeletal muscle stem cells, known as satel...

Over 185,000 limb amputations are performed in the United States annually, many of which are due to the sequelae of peripheral vascular disease. Symptomatic neuromas remain a significant source of postamputation morbidity and contribute to both phantom limb (PLP) and residual limb pain (RLP). While many interventions have been proposed for the trea...

Background. Robotic exoskeleton devices have become a promising modality for restoration of extremity function in individuals with limb loss or functional weakness. However, there exists no consistent or reliable way to record efferent motor action potentials from intact peripheral nerves to control device movement. Peripheral nerve motor action po...

Pain is a central feature of soft tissue trauma, which under certain contexts, results in aberrant osteochondral differentiation of tissue-specific stem cells. Here, the role of sensory nerve fibers in this abnormal cell fate decision is investigated using a severe extremity injury model in mice. Soft tissue trauma results in NGF (Nerve growth fact...

Objective: To determine the impact of gender-affirming mastectomy on depression, anxiety, and body image. Background: There are many cross-sectional and ad-hoc studies demonstrating the benefits of gender-affirming surgery. There are few prospective investigations of patient-reported outcomes in gender-affirming surgery using validated instrumen...

The quest to find the ideal prosthetic device interface that enables intuitive control has motivated several recent innovations. Although current prosthetic device control strategies have advanced the field of neuroprosthetic control, they are limited in their ability to generate reliable, stable, and specific signals to replicate the complex movem...

Purpose: Exoskeletons have become a promising device to restore extremity function to those with limb weakness. However, these devices have not become widely adopted due to the inadequacy of current nerve interfacing methods. The Muscle Cuff Regenerative Peripheral Nerve Interface (MC-RPNI) was developed as a potential solution to this problem. Con...

Purpose: Although advanced prosthetic devices have the potential to allow fine-motor movements and extract somatosensory signals via sensitive pressure sensors, an ideal interface to integrate the human nervous system with the prosthetic doesn’t exist. Furthermore, the requirement for the implantation of indwelling electrodes and prohibitive costs...

While recent advances have occurred in the field of prosthetic technology, there is still a need for a neuroprosthetic interface that permits high-fidelity prosthetic control to accurately replicate extremity movements. Peripheral nerve interfaces offer more intuitive prosthetic control by harnessing neural signals at a fascicular level. The direct...

Although aesthetic surgery is a core component of plastic surgery education and training, meaningful exposure to aesthetic surgery remains a challenge for most academic training programs in North America. Not surprisingly, the lack of exposure to aesthetic surgical procedures during training results in graduating residents with lower confidence in...

Systemic scleroderma is a chronic connective tissue disease characterized by internal organ and skin fibrosis. Unfortunately, there is a lack of efficacious treatments for cutaneous manifestations, and alternative interventions should be considered. Fat grafting has gained significant attention due to its regenerative properties and success in impr...

Introduction Regenerative peripheral nerve interfaces (RPNIs) transduce neural signals to provide high‐fidelity control of neuroprosthetic devices. Traditionally, rat RPNIs are constructed with ~150 mg of free skeletal muscle grafts. It is unknown whether larger free muscle grafts allow RPNIs to transduce greater signal. Methods RPNIs were constru...

Despite recent advances in microsurgical techniques, functional recovery following peripheral nerve injury remains slow and inadequate. Poor peripheral nerve regeneration not only leaves patients with significant impairments, but also commonly leads to the development of debilitating neuropathic pain. Recent research has demonstrated the potential...

Background: Although the benefits of gender-affirming surgery may be apparent to patients and providers, there remains a paucity of studies assessing the impact of these procedures. As an initial step, preoperative patient-reported outcomes using validated measures of depression, anxiety, and body image were used and compared to cisgender normativ...