Update on Upper Limb Neuroma Management.

Painful terminal neuromas in the upper limb due to nerve injury are common. Neuroma symptoms include a sharp and burning sensation, cold intolerance, dysesthesia, pain, numbness, and paresthesia. These symptoms could have a negative impact on the functional ability of the patient and quality of life. In addition, Prostheses use might be abandoned by amputees due to neuroma-induced pain. Many clinicians face challenges while managing neuromas. Contemporary "active" methods like regenerative peripheral nerve interface (RPNI), targeted muscle reinnervation (TMR), and processed nerve allograft repair (PNA) are replacing the conventional "passive" approaches such as excision, transposition, and implantation techniques. RPNI involves inducing axonal sprouting by transplanting the free end of a peripheral nerve into a free muscle graft. TMR includes reassigning the role of the peripheral nerve by the transfer of the distal end of a pure sensory or a mixed peripheral nerve to a motor nerve of a nearby muscle segment. To give the peripheral nerve a pathway to re-innervate its target tissue, PNA entails implanting a sterile extracellular matrix prepared from decellularized and regenerated human nerve tissue with preserved epineurium and fascicles. Of these, RPNI and TMR appear to hold a promising treatment for nerve-ending neuromas and prevent their relapse. In contrast, PNA may reduce neuroma pain and allow meaningful nerve repair. The aim of this article is to provide an overview of the newer approaches of TMR, RPNI, and PNA and discuss their implications, surgical techniques, and reported consequences.

Targeted Muscle Reinnervation: Outcomes in Treating Chronic Pain Secondary to Extremity Amputation and Phantom Limb Syndrome.

BACKGROUND: Secondary to vascular disease, oncological resection, or devastating trauma, lower extremity amputations are performed globally at a yearly rate exceeding 1 million patients. Three-quarters of these patients will develop chronic pain or phantom pain, which presents a functional limitation for prosthetic use and contributes to deconditioning and increased mortality. Targeted muscle reinnervation (TMR) presents a surgical solution to this problem as either a primary or secondary intervention. METHODS: A review of the existing literature was conducted using a combination of the terms "phantom pain" "chronic pain," "neuroma," and "targeted muscle reinnervation" in Medline and PubMed. RESULTS: Five articles were found which addressed TMR for pain syndromes, four of which involved lower extremity amputation. Four of the articles were retrospective reviews, and one was a randomized control trial. A total of 149 patients were included, of which 82 underwent lower extremity amputation. Ninety-two of the patients underwent prophylactic TMR, of which 57 were secondary procedures.In patients who underwent TMR at the time of amputation, all studies reported a minimal development of symptomatic neuromas (27%). For secondary TMR, near-complete resolution of previous pain was found (90%). Phantom pain was noted to be similar to other studies in the literature but noted to improve over time with both primary (average drop of 3.5 out of 10 points on the numerical rating scale) and secondary (diminishing from 72% of patients to 13% over 6 months) operations. CONCLUSION: Although much of the current literature is limited to retrospective studies with few patients, these data point toward near-complete resolution of neuroma pain after treatment as well as complete prevention of chronic pain if TMR is used as a prophylactic measure during the index amputation. THIS STUDY WAS A LEVEL OF EVIDENCE IV: .

Targeted muscle reinnervation in oncologic amputees: Early experience of a novel institutional protocol.

BACKGROUND: We describe a multidisciplinary approach for comprehensive care of amputees with concurrent targeted muscle reinnervation (TMR) at the time of amputation. METHODS: Our TMR cohort was compared to a cross-sectional sample of unselected oncologic amputees not treated at our institution (N = 58). Patient-Reported Outcomes Measurement Information System (NRS, PROMIS) were used to assess postamputation pain. RESULTS: Thirty-one patients underwent amputation with concurrent TMR during the study; 27 patients completed pain surveys; 15 had greater than 1 year follow-up (mean follow-up 14.7 months). Neuroma symptoms occurred significantly less frequently and with less intensity among the TMR cohort. Mean differences for PROMIS pain intensity, behavior, and interference for phantom limb pain (PLP) were 5.855 (95%CI 1.159-10.55; P = .015), 5.896 (95%CI 0.492-11.30; P = .033), and 7.435 (95%CI 1.797-13.07; P = .011) respectively, with lower scores for TMR cohort. For residual limb pain, PROMIS pain intensity, behavior, and interference mean differences were 5.477 (95%CI 0.528-10.42; P = .031), 6.195 (95%CI 0.705-11.69; P = .028), and 6.816 (95%CI 1.438-12.2; P = .014), respectively. Fifty-six percent took opioids before amputation compared to 22% at 1 year postoperatively. CONCLUSIONS: Multidisciplinary care of amputees including concurrent amputation and TMR, multimodal postoperative pain management, amputee-centered rehabilitation, and peer support demonstrates reduced incidence and severity of neuroma and PLP.

Pedicled Serratus Anterior Flap as an Alternative Muscle Target for Targeted Muscle Reinnervation in Transhumeral Amputees.

Upper limb amputation is a universally devastating injury that results in substantial loss of function. Myoelectric prostheses represent a new generation of battery-powered programmable prostheses controlled by EMG signals. The aim of upper limb targeted muscle reinnervation (TMR) is to enhance the control of a myoelectric prosthesis by improving the number and quality of EMG signals that can be used to control prosthetic elbow, wrist, and hand movements. Current TMR techniques rely on preservation of parts of biceps and triceps to be used as reinnervated muscle targets. However, a subset of amputations exists in which the proximity or mechanism of injury results in loss of these local muscle targets, making these techniques less suitable. Alternative muscles beyond the zone of injury must be sought and imported as targets for residual nerves. Through its neurovascular anatomy and physical structure, the serratus anterior offers multiple potential targets in close vicinity to the upper limb, making the creation of additional signals through a single flap achievable in this challenging scenario. We present our technique using a pedicled serratus anterior muscle flap as an alternative muscle target in transhumeral amputees undergoing TMR.

Common Synaptic Input to Motor Neurons and Neural Drive to Targeted Reinnervated Muscles.

We compared the behavior of motor neurons innervating their physiological muscle targets with motor neurons from the same spinal segment whose axons were surgically redirected to remnant muscles (targeted muscle reinnervation). The objective was to assess whether motor neurons with nonphysiological innervation receive similar synaptic input and could be voluntary controlled as motor neurons with natural innervation. For this purpose, we acquired high-density EMG signals from the biceps brachii in 5 male transhumeral amputees who underwent targeted reinnervation of this muscle by the ulnar nerve and from the first dorsal interosseous muscle of 5 healthy individuals to investigate the natural innervation of the ulnar nerve. The same recordings were also performed from the biceps brachii muscle of additional 5 able-bodied individuals. The EMG signals were decomposed into discharges of motor unit action potentials. Motor neurons were progressively recruited for the full range of submaximal muscle activation in all conditions. Moreover, their discharge rate significantly increased from recruitment to target activation level in a similar way across the subject groups. Motor neurons across all subject groups received common synaptic input as identified by coherence analysis of their spike trains. However, the relative strength of common input in both the delta (0.5-5 Hz) and alpha (5-13 Hz) bands was significantly smaller for the surgically reinnervated motor neuron pool with respect to the corresponding physiologically innervated one. The results support the novel approach of motor neuron interfacing for prosthesis control and provide new insights into the role of afferent input on motor neuron activity.SIGNIFICANCE STATEMENT Targeted muscle reinnervation surgically redirects nerves that lost their target in the amputation into redundant muscles in the region of the stump. The study of the behavior of motor neurons following this surgery is needed for designing biologically inspired prosthetic control strategies. Moreover, targeted muscle reinnervation offers a human experimental framework for studying the control and behavior of motor neurons when changing their target innervated muscle fibers and sensory feedback. Here, we show that the control of motor neurons and their synaptic input, following reinnervation, was remarkably similar to that of the physiological innervation, although with reduced common drive at some frequencies. The results advance our knowledge on the role of sensory input in the generation of the neural drive to muscles and provide the basis for designing physiologically inspired methods for prosthesis control.

Targeted muscle reinnervation and prosthetic rehabilitation after limb loss.

Over one million amputations occur annually world-wide. Often, amputation of the neoplastic limb is regarded as a surgical failure and the end of surgical care for the patient. Here, we highlight the advancements in extremity prostheses and surgical techniques that should change that mindset. Myoelectric prostheses, osseointegration, and targeted muscle reinnervation allow for more intuitive and easy to use devices, reduced pain, and greater quality of life for amputees.

Intense Focused Ultrasound Preferentially Stimulates Transected Nerves Within Residual Limbs: Pilot Study.

Objective: Identifying pain generators in tissue deep in the skin can require uncomfortable, complicated, and invasive tests. We describe pilot studies testing the hypothesis that ultrasound image-guided, intense focused ultrasound (ig-iFU) can noninvasively and differentially stimulate the end of transected nerves in the residual limbs of amputee patients. Design: We applied iFU to the transected nerve ending as individual pulses with a length of 0.1 seconds using a carrier frequency of 2.0 MHz. After targeting, we gradually increased the iFU intensity to reach consistent patient-reported stimulation of the transected nerve ending. We also stimulated the proximal nerve, tissue near the nerve ending, and the intact contralateral nerve. We described the resulting sensations and correlated the results of the study participant's pre-iFU study responses to phantom and residual limb pain questionnaires. Results: iFU spatial and temporal average intensity values between 16 W/cm2 and 433 W/cm2 that were applied to the transected nerve ending and proximal nerve elicited sensations, including phantom limb sensations, while the same intensity applied to control tissue centimeters away from the nerve ending, or to the intact nerve on the contralateral limb, did not. Two out of 11 study participants reported only mild and transient pain created by iFU stimulation. Successful iFU intensity values correlated with neither phantom nor residual limb pain scores. Conclusions: Transected nerves had greater sensitivity to iFU stimulation than ipsilateral and contralateral control tissue, including intact nerve. These results support the view that ig-iFU may one day help physicians identify deep, tender tissue in patients who report experiencing pain.

The Effect of Split Nerve on Electromyography Signal Pattern in a Rat Model.

BACKGROUND: Recent developments of prosthetic arm are based on the use of electromyography (EMG) signals. To provide improvements, such as coordinated movement of multiple joints and greater control intuitiveness, higher variability of EMG signals is needed. By splitting a nerve lengthwise, connecting each half to new target muscles, and employing a program to assign each biosignal pattern to a specific movement, we hope to enrich the number of biosignal sites on amputees' stump. METHODS: We split the gastrocnemius muscle of 12 Sprague-Dawley rats into two muscle heads, searched for the peroneal nerve, divided them lengthwise, and connected one half of the nerve to the tibial nerve innervating both muscle heads (SN_50, n = 8). In another group, we connected the undivided peroneal nerve to the nerve of a single muscle head (non-SN_100, n = 6), while the other muscle head received different innervation (non-SN_0, n = 6). After 10 weeks, we stimulated the peroneal nerve and measured the EMG amplitude. RESULTS: Mean EMG amplitude of the muscle head innervated by one half of the nerve (SN_50; 1.77 [range: 0.71-3.24] mV) and by the undivided nerve (non-SN_100; 3.45 mV [range: 1.13-5.34]) was not significantly different. However, the mean EMG amplitude produced by SN_50 was significantly different from that of the other innervation (i.e., non-SN_0; 0.76 mV [range: 0.41-1.35]), indicating the presence of noise. CONCLUSION: Split nerve in combination with split-muscle procedure can yield a meaningful EMG signal that might be used to convey the intention of living organism to a machine.

Magnetic resonance spectroscopy of current hand amputees reveals evidence for neuronal-level changes in former sensorimotor cortex.

Deafferentation is accompanied by large-scale functional reorganization of maps in the primary sensory and motor areas of the hemisphere contralateral to injury. Animal models of deafferentation suggest a variety of cellular-level changes including depression of neuronal metabolism and even neuronal death. Whether similar neuronal changes contribute to patterns of reorganization within the contralateral sensorimotor cortex of chronic human amputees is uncertain. We used functional MRI-guided proton magnetic resonance spectroscopy to test the hypothesis that unilateral deafferentation is associated with lower levels of N-acetylaspartate (NAA, a putative marker of neuronal integrity) in the sensorimotor hand territory located contralateral to the missing hand in chronic amputees (n = 19) compared with the analogous hand territory of age- and sex-matched healthy controls (n = 28). We also tested whether former amputees [i.e., recipients of replanted (n = 3) or transplanted (n = 2) hands] exhibit NAA levels that are indistinguishable from controls, possible evidence for reversal of the effects of deafferentation. As predicted, relative to controls, current amputees exhibited lower levels of NAA that were negatively and significantly correlated with the time after amputation. Contrary to our prediction, NAA levels in both replanted and transplanted patients fell within the range of the current amputees. We suggest that lower levels of NAA in current amputees reflects altered neuronal integrity consequent to chronic deafferentation. Thus local changes in NAA levels may provide a means of assessing neuroplastic changes in deafferented cortex. Results from former amputees suggest that these changes may not be readily reversible through reafferentation.NEW & NOTEWORTHY This study is the first to use functional magnetic resonance-guided magnetic resonance spectroscopy to examine neurochemical mechanisms underlying functional reorganization in the primary somatosensory and motor cortices consequent to upper extremity amputation and its potential reversal through hand replantation or transplantation. We provide evidence for selective alteration of cortical neuronal integrity associated with amputation-related deafferentation that may not be reversible.

Pedicled Sensate Composite Calcaneal Flap in Children With Congenital Tibial Pseudoarthrosis.

BACKGROUND: The preservation and functionality of a limb affected by a malformation (such as congenital pseudoarthrosis of the tibia) or a severely mangled lower limb in children, despite modern reconstructive techniques, remains challenging, often eventually requiring amputation to achieve a better outcome. The classical Syme and Boyd procedures are functionally better than transtibial (TT) amputation, but are not feasible for congenital tibial pseudoarthrosis. TT amputation delivers an excellent, effective, and functional stump that usually leads, after prosthetization, to a functional gait. Unfortunately, in some situations, particularly when amputation is performed conventionally, the stump is also associated with complications. Future surgical revisions are often needed, particularly in children, because of stump overgrowth. METHODS: Between 2008 and 2010, three patients diagnosed with congenital pseudoarthrosis of the tibia associated with neurofibromatosis who were indicated for TT amputation with calcaneal flap after failure of all previous surgical reconstructive procedures were selected. The chosen method for osteosynthesis was an external fixator of Ilizarov. RESULTS: At 12 weeks of follow-up, the stump had healed in all three patients, and tibiocalcaneal fusion was achieved without complications. All patients were prosthetized and had an asymptomatic gait. After a minimum follow-up of 6 years, all three cases with the pedicled sensate composite calcaneal flap still had a strong, full weight-bearing surface and have adapted easily to the conventional prosthesis, providing a painless stump with excellent functionality. CONCLUSION: With a 0 rate of needed revisions, all 3 cases with the pedicled sensate composite calcaneal flap preserving the hind foot still have a strong, full weight-bearing surface and have easily adapted to the conventional prosthesis, providing a painless and excellent functional stump that could last a lifetime. LEVEL OF EVIDENCE: Level IV.

Targeted Muscle Reinnervation in the Upper Extremity Amputee: A Technical Roadmap.

Targeted muscle reinnervation (TMR) offers the potential for improved prosthetic function by reclaiming the neural control information that is lost as a result of upper extremity amputation. In addition to the prosthetic control benefits, TMR is a potential treatment for postamputation neuroma pain. Here, we present our surgical technique for TMR nerve transfers in transhumeral and shoulder disarticulation patients.

Targeted muscle reinnervation: a novel approach to postamputation neuroma pain.

BACKGROUND: Postamputation neuroma pain can prevent comfortable prosthesis wear in patients with limb amputations, and currently available treatments are not consistently effective. Targeted muscle reinnervation (TMR) is a decade-old technique that employs a series of novel nerve transfers to permit intuitive control of upper-limb prostheses. Clinical experience suggests that it may also serve as an effective therapy for postamputation neuroma pain; however, this has not been explicitly studied. QUESTIONS/PURPOSES: We evaluated the effect of TMR on residual limb neuroma pain in upper-extremity amputees. METHODS: We conducted a retrospective medical record review of all 28 patients treated with TMR from 2002 to 2012 at Northwestern Memorial Hospital/Rehabilitation Institute of Chicago (Chicago, IL, USA) and San Antonio Military Medical Center (San Antonio, TX, USA). Twenty-six of 28 patients had sufficient (> 6 months) followup for study inclusion. The amputation levels were shoulder disarticulation (10 patients) and transhumeral (16 patients). All patients underwent TMR for the primary purpose of improved myoelectric control. Of the 26 patients included in the study, 15 patients had evidence of postamputation neuroma pain before undergoing TMR. RESULTS: Of the 15 patients presenting with neuroma pain before TMR, 14 experienced complete resolution of pain in the transferred nerves, and the remaining patient's pain improved (though did not resolve). None of the patients who presented without evidence of postamputation neuroma pain developed neuroma pain after the TMR procedure. All 26 patients were fitted with a prosthesis, and 23 of the 26 patients were able to operate a TMR-controlled prosthesis. CONCLUSIONS: None of the 26 patients who underwent TMR demonstrated evidence of new neuroma pain after the procedure, and all but one of the 15 patients who presented with preoperative neuroma pain experienced complete relief of pain in the distribution of the transferred nerves. TMR offers a novel and potentially more effective therapy for the management of neuroma pain after limb amputation.

Does targeted nerve implantation reduce neuroma pain in amputees?

BACKGROUND: Symptomatic neuroma occurs in 13% to 32% of amputees, causing pain and limiting or preventing the use of prosthetic devices. Targeted nerve implantation (TNI) is a procedure that seeks to prevent or treat neuroma-related pain in amputees by implanting the proximal amputated nerve stump onto a surgically denervated portion of a nearby muscle at a secondary motor point so that regenerating axons might arborize into the intramuscular motor nerve branches rather than form a neuroma. However, the efficacy of this approach has not been demonstrated. QUESTIONS/PURPOSES: We asked: Does TNI (1) prevent primary neuroma-related pain in the setting of acute traumatic amputation and (2) reduce established neuroma pain in upper- and lower-extremity amputees? METHODS: We retrospectively reviewed two groups of patients treated by one surgeon: (1) 12 patients who underwent primary TNI for neuroma prevention at the time of acute amputation and (2) 23 patients with established neuromas who underwent neuroma excision with secondary TNI. The primary outcome was the presence or absence of palpation-induced neuroma pain at last followup, based on a review of medical records. The patients presented here represent 71% of those who underwent primary TNI (12 of 17) and 79% of those who underwent neuroma excision with secondary TNI (23 of 29 patients) during the period in question; the others were lost to followup. Minimum followup was 8 months (mean, 22 months; range, 8-60 months) for the primary TNI group and 4 months (mean, 22 months; range, 4-72 months) for the secondary TNI group. RESULTS: At last followup, 11 of 12 patients (92%) after primary TNI and 20 of 23 patients (87%) after secondary TNI were free of palpation-induced neuroma pain. CONCLUSIONS: TNI performed either primarily at the time of acute amputation or secondarily for the treatment of established symptomatic neuroma is associated with a low frequency of neuroma-related pain. By providing a distal target for regenerating axons, TNI may offer an effective strategy for the prevention and treatment of neuroma pain in amputees.

Treatment of phantom limb pain by cryoneurolysis of the amputated nerve.

The pathophysiology of phantom limb pain (PLP) is multifactorial. It probably starts in the periphery and is amplified and modified in the central nervous system. A small group of patients with PLP were questioned as to the portion of the phantom limb affected by pain (e.g., "great toe," "thumb"). In the stump, the corresponding amputated nerve was located with a nerve stimulator. With correct placement and stimulation, the PLP could then be reproduced or exacerbated. A small dose of local anesthesia was then injected, resulting in the disappearance of the PLP. If a peripheral nerve injection gave temporary relief, our final treatment was cryoanalgesia at this location. Evaluation of 5 patients, followed for at least 2.5 years, yielded the following results: 3 patients had excellent results (100%, 95%, and 90% decrease in complaints, respectively), 1 patient had an acceptable result (40% decrease), and 1 patient had only a 20% decrease in pain. Although both central and peripheral components are likely involved in PLP, treatment of a peripheral pain locus with cryoanalgesia should be considered. We propose the identification of a peripheral etiology may help match patients to an appropriate therapy, and cryoanalgesia may result in long-term relief of PLP.

[Prosthetic Fitting Concepts after Major Amputation in the Upper Limb - an Overview of Current Possibilities]. / Prothetische Versorgungskonzepte nach Majoramputation der oberen Extremität ­ eine Übersicht gegenwärtiger Möglichkeiten.

BACKGROUND: The upper extremity and particularly the hands are crucial for patients in interacting with their environment, therefore amputations or severe damage with loss of hand function significantly impact their quality of life. In cases where biological reconstruction is not feasible or does not lead to sufficient success, bionic reconstruction plays a key role in patient care. Classical myoelectric prostheses are controlled using two signals derived from surface electrodes in the area of the stump muscles. Prosthesis control, especially in high amputations, is then limited and cumbersome. The surgical technique of Targeted Muscle Reinnervation (TMR) offers an innovative solution: The major arm nerves that have lost their target organs due to amputation are rerouted to muscles in the stump area. This enables the establishment of cognitive control signals that allow significantly improved prosthesis control. PATIENTS/MATERIALS AND METHODS: A selective literature review on TMR and bionic reconstruction was conducted, incorporating relevant articles and discussing them considering the clinical experience of our research group. Additionally, a clinical case is presented. RESULTS: Bionic reconstruction combined with Targeted Muscle Reinnervation enables intuitive prosthetic control with simultaneous movement of various prosthetic degrees of freedom and the treatment of neuroma and phantom limb pain. Long-term success requires a high level of patient compliance and intensive signal training during the prosthetic rehabilitation phase. Despite technological advances, challenges persist, especially in enhancing signal transmission and integrating natural sensory feedback into bionic prostheses. CONCLUSION: TMR surgery represents a significant advancement in the bionic care of amputees. Employing selective nerve transfers for signal multiplication and amplification, opens up possibilities for improving myoelectric prosthesis function and thus enhancing patient care. Advances in the area of external prosthetic components, improvements in the skeletal connection due to osseointegration and more fluid signal transmission using wireless, fully implanted electrode systems will lead to significant progress in bionic reconstruction, both in terms of precision of movement and embodiment.

Active nerve management for above the knee amputation: A comparison of through the wound versus posterior approach.

Targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI) are used to prevent or treat neuromas in amputees. TMR for above-the-knee amputation (AKA) is most commonly performed through a posterior incision rather than the stump wound because recipient motor nerves are primarily located in the proximal third of the thigh. When preventative TMR is performed with concurrent AKA, a posterior approach requires intraoperative repositioning and an additional incision. The purpose of this study was to evaluate feasibility of TMR and operative times for nerve management performed through the wound compared to a posterior approach in AKA patients to guide surgical decision-making. Patients who underwent AKA with TMR between 2018-2023 were reviewed. Patients were divided into two groups: TMR performed through the wound (Group I) and TMR performed through a posterior approach (Group II). If a nerve was unable to undergo coaptation for TMR due to the lack of suitable donor motor nerves, RPNI was performed. Eighteen patients underwent AKA with nerve management were included from Group I (8 patients) and Group II (10 patients). TMR coaptations performed on distinct nerves was 1.5 ± 0.5 in Group I compared to 2.6 ± 0.5 in Group II (p = 0.001). Operative time for Group I was 200.7 ± 33.4 min compared to 326.5 ± 37.1 min in Group II (p = 0.001). TMR performed through the wound following AKA requires less operative time than a posterior approach. However, since recipient motor nerves are not consistently found near the stump, RPNI may be required with TMR whereas the posterior approach allows for more TMR coaptations.

[Bionic Surgery Meets Bionic Reconstruction - First In-human use of Robotic Microsurgery in Targeted Muscle Reinnervation]. / Bionische Chirurgie trifft Bionische Rekonstruktion ­ erstes in-human Projekt von robotischer Mikrochirurgie zur Targeted Muscle Reinnervation.

Robotic microsurgery is an emerging field in reconstructive surgery, which provides benefits such as improved precision, optimal ergonomics, and reduced tremors. However, only a few robotic platforms are available for performing microsurgical procedures, and successful nerve coaptation is still a challenge. Targeted muscle reinnervation (TMR) is an innovative reconstructive procedure that rewires multiple nerves to remnant stump muscles, thereby reducing neuroma and phantom limb pain and improving the control of bionic prostheses. The precision of surgical techniques is critical in reducing axonal sprouting around the coaptation site to minimise the potential for neuroma formation. This study reports the first use of a microsurgical robotic platform for multiple nerve transfers in a patient undergoing TMR for bionic extremity reconstruction. The Symani robotic platform, combined with external microscope magnification, was successfully used, and precise handling of nerve tissue and coaptation was easily feasible even in anatomically challenging environments. While the precision and stability offered by robotic assistance may be especially useful for nerve surgery, the high economic costs of robotic microsurgery remain a major challenge for current healthcare systems. In conclusion, this study demonstrated the feasibility of using a robotic microsurgical platform for nerve surgery and transfers, where precise handling of tissue is crucial and limited space is available. Future studies will explore the full potential of robotic microsurgery in the future.

Functional expansion of sensorimotor representation and structural reorganization of callosal connections in lower limb amputees.

Previous studies have indicated that amputation or deafferentation of a limb induces functional changes in sensory (S1) and motor (M1) cortices, related to phantom limb pain. However, the extent of cortical reorganization after lower limb amputation in patients with nonpainful phantom phenomena remains uncertain. In this study, we combined functional magnetic resonance (fMRI) and diffusion tensor imaging (DTI) to investigate the existence and extent of cortical and callosal plasticity in these subjects. Nine "painless" patients with lower limb amputation and nine control subjects (sex- and age-matched) underwent a 3-T MRI protocol, including fMRI with somatosensory stimulation. In amputees, we observed an expansion of activation maps of the stump in S1 and M1 of the deafferented hemisphere, spreading to neighboring regions that represent the trunk and upper limbs. We also observed that tactile stimulation of the intact foot in amputees induced a greater activation of ipsilateral S1, when compared with controls. These results demonstrate a functional remapping of S1 in lower limb amputees. However, in contrast to previous studies, these neuroplastic changes do not appear to be dependent on phantom pain but do also occur in those who reported only the presence of phantom sensation without pain. In addition, our findings indicate that amputation of a limb also induces changes in the cortical representation of the intact limb. Finally, DTI analysis showed structural changes in the corpus callosum of amputees, compatible with the hypothesis that phantom sensations may depend on inhibitory release in the sensorimotor cortex.

[The surgical treatment of peripheral neuromas]. / De chirurgische behandeling van perifere neuromen.

Peripheral neuromas are a prevalent problem following nerve injury or certain surgical interventions like limb amputation. It is important to consider a peripheral neuroma when a patient experiences pain in the innervation area of a peripheral sensory or mixed nerve (branch), especially following trauma or amputation. Adequate recognition of a painful neuroma is crucial to treat patients satisfactorily for their invalidating and chronic symptoms. We want to emphasize that surgical intervention can be an effective and permanent treatment for symptomatic neuromas. The standard surgical treatment is neuroma excision and burying of the nerve stump in adjacent muscle. However, there is a shift towards new and active techniques like Targeted Muscle Reinnervation, of which future comparative research will have to demonstrate whether it is more effective in treating peripheral neuroma pain than conventional surgery.

[The surgical treatment of peripheral neuromas]. / De chirurgische behandeling van perifere neuromen.

Peripheral neuromas are a prevalent problem following nerve injury or certain surgical interventions like limb amputation. It is important to consider a peripheral neuroma when a patient experiences pain in the innervation area of a peripheral sensory or mixed nerve (branch), especially following trauma or amputation. Adequate recognition of a painful neuroma is crucial to treat patients satisfactorily for their invalidating and chronic symptoms. We want to emphasize that surgical intervention can be an effective and permanent treatment for symptomatic neuromas. The standard surgical treatment is neuroma excision and burying of the nerve stump in adjacent muscle. However, there is a shift towards new and active techniques like Targeted Muscle Reinnervation, of which future comparative research will have to demonstrate whether it is more effective in treating peripheral neuroma pain than conventional surgery.