In JoVE (2)

Other Publications (32)

Articles by Oskar C. Aszmann in JoVE

 JoVE Behavior

A Structured Rehabilitation Protocol for Improved Multifunctional Prosthetic Control: A Case Study

1Christian Doppler Laboratory for Restoration of Extremity Function, 2Department of Surgery, Division of Plastic and Reconstructive Surgery, Medical University of Vienna, 3Department of Neurorehabilitation Engineering, Bernstein Focus Neurotechnology Göttingen, 4University Medical Center Göttingen, Georg-August University, 5University of Applied Sciences FH Campus Wien, 6Research & Development, Otto Bock Healthcare Products GmbH


JoVE 52968

 JoVE Biology

A Rapid Automated Protocol for Muscle Fiber Population Analysis in Rat Muscle Cross Sections Using Myosin Heavy Chain Immunohistochemistry

1CD Laboratory for the Restoration of Extremity Function, Division of Plastic and Reconstructive Surgery, Department of Surgery, Medical University of Vienna, 2Core Facility Imaging, Core Facilities, Medical University Vienna, 3Department of Hand, Plastic and Reconstructive Surgery, Burn Center, BG Trauma Center Ludwigshafen, Plastic and Hand Surgery, University of Heidelberg


JoVE 55441

Other articles by Oskar C. Aszmann on PubMed

Simultaneous GDNF and BDNF Application Leads to Increased Motoneuron Survival and Improved Functional Outcome in an Experimental Model for Obstetric Brachial Plexus Lesions

Plastic and Reconstructive Surgery. Sep, 2002  |  Pubmed ID: 12198419

Motoneurons of the neonate rat respond to proximal axonal injury with morphologic and functional changes and ultimately with neuronal death. Recent studies showed that both glial cell-line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) reduce induced degeneration of motoneurons after axotomy and avulsion. Whether rescued motoneurons are functionally intact has been argued. In the present investigation, the authors have used a proximal crush lesion of the brachial plexus in neonatal rats as the experimental model of neuronal injury. This allowed the authors to study the effects of trophic factor administration on injured motoneurons and the relationship between motoneuron survival and extremity function. Trophic factors were locally released by small polymer implants in a low-dose slow-release mode. Six groups of 10 animals were prepared: BDNF, GDNF, GDNF/BDNF, control, sham, and normals. The number of surviving motoneurons was determined by retrograde tracer techniques using Fluorogold and Fastblue. Extremity function was quantitatively evaluated with functional muscle testing at day 56. The results of this study demonstrate that trophic factors applied separately had no effect, whereas combined trophic factor application (GDNF/BDNF group) had a dramatic rescue effect on motoneuron survival as compared with the control groups, which also effected significantly greater strength. The authors conclude that a combination of trophic factors leads to enhanced motoneuron survival, with improved voluntary function as the animal enters adulthood so that exogenous trophic support of motoneurons might have a role in the treatment of all types of severe neonatal plexopathies, maintaining the viability of motoneurons until reconstructive surgery provides them with a pathway for regeneration and endogenous trophic support.

Neuroma Prevention by End-to-side Neurorraphy: an Experimental Study in Rats

The Journal of Hand Surgery. Nov, 2003  |  Pubmed ID: 14642521

The successful treatment of painful neuromas remains a difficult goal to attain. In this report we explore the feasibility of neuroma prevention by insertion of the proximal end of a nerve through an end-to-side neurorraphy into an adjacent mixed nerve to provide a pathway and target for axons deprived of their end organ.

The Influence of GDNF on the Timecourse and Extent of Motoneuron Loss in the Cervical Spinal Cord After Brachial Plexus Injury in the Neonate

Neurological Research. Mar, 2004  |  Pubmed ID: 15072641

Injuries of the peripheral nerve in the early post-natal period are known to cause massive loss in the motoneuron pools of the spinal cord. However, the exact time frame and extent of motoneuron death in the cervical spinal cord after a brachial plexus lesion and the altered course after neuroprotection with different trophic factors is not known. In the present study, the time course of induced motoneuron death after a neonatal peripheral nerve injury and the effect of GDNF was investigated over a 4 week time period to determine the window of opportunity for possible therapeutic interventions in obstetrical plexus palsy. The brachial plexus of a total of 70 animals was explored within 12 hours after birth and divided at trunc level. The plexus was then labeled with a fluorescent tracer to identify the corresponding motoneuron pool. Two groups were prepared: Group I remained untreated to assess the natural course of induced neuronal death. Group II received GDNF immediately after the lesion. Post-operatively the animals were evaluated sequentially over 29 days. Surviving motoneurons were evaluated quantitatively counting the nucleoli. The entire brachial plexus of the rat is supplied by a total of about 4000 motoneurons. After injury the number of motoneurons steadily diminished within the first 10 days to reach a plateau of about 20% of the original number. At this time the GDNF treated group still had 85% (3330 +/- 247) of motoneurons viable. This further decreased so that at the termination of the experiment at day 29 there were still 2527 +/- 285 motoneurons alive. This study clearly shows that pathology after a brachial plexus injury in the newborn is not restricted to the peripheral nerve alone. In this model 64% of motoneurons underwent apoptosis within the first week after injury, reaching a plateau after 10 days at 20%. GDNF successfully rescued motoneurons so that after 4 weeks still 65% were present. We conclude that GDNF leads to enhanced motoneuron survival so that exogenous trophic support of motoneurons might have a role in the treatment of all types of severe neonatal plexopathies, maintaining the viability of motoneurons until reconstructive surgery provides them with a pathway for regeneration and endogenous trophic support.

Changes in Spinal Cord Architecture After Brachial Plexus Injury in the Newborn

Brain : a Journal of Neurology. Jul, 2004  |  Pubmed ID: 15175226

Obstetric brachial plexus palsy is a devastating birth injury. While many children recover spontaneously, 20-25% are left with a permanent impairment of the affected limb. So far, concepts of pathology and recovery have focused on the injury of the peripheral nerve. Proximal nerve injury at birth, however, leads to massive injury-induced motoneuron loss in corresponding motoneuron pools and therefore limits the extent of functional recovery. In the present study, the role of spinal cord plasticity after injury and recovery from obstetric brachial plexus lesions was investigated. A selective injury to spinal roots C5 and C6 was induced in newborn Sprague-Dawley rats, leading to motoneuron loss in corresponding motoneuron pools. Recovery of extremity function was evaluated with different behavioural paradigms. Permanent changes of adjacent motoneuron pools were quantitatively evaluated by retrograde tracing and functional muscle testing. We report that the adjacent C7 motoneuron contribution to biceps muscle innervation increased four-fold after upper trunk lesions in newborns, thus compensating for the injury-induced motoneuron loss. These results indicate that, in obstetric brachial plexus palsy, changes in spinal cord architecture are an integral part not only of primary pathology but also of the subsequent recovery process. While present treatment is directed towards the restoration of neural continuity, future treatment strategies must recognize and take advantage of CNS participation in the injury and recovery process.

Anatomy of Pudendal Nerve at Urogenital Diaphragm--new Critical Site for Nerve Entrapment

Urology. Nov, 2005  |  Pubmed ID: 16286101

To investigate the relations of the pudendal nerve in this complex anatomic region and determine possible entrapment sites that are accessible for surgical decompression. Entrapment neuropathies of the pudendal nerve are an uncommon and, therefore, often overlooked or misdiagnosed clinical entity. The detailed relations of this nerve as it exits the pelvis through the urogenital diaphragm and enters the mobile part of the penis have not yet been studied.

Reconstruction of a Large Abdominal Tissue Defect with Composite Tissue Using Autologous Dermis-vicryl-skin Sandwich Graft

Plastic and Reconstructive Surgery. Apr, 2006  |  Pubmed ID: 16641754

Bridging Critical Nerve Defects Through an Acellular Homograft Seeded with Autologous Schwann Cells Obtained from a Regeneration Neuroma of the Proximal Stump

Journal of Reconstructive Microsurgery. Apr, 2008  |  Pubmed ID: 18438750

Over the last decade, several models have investigated the usefulness of different biologic and/or synthetic matrices as alternatives to conventional nerve grafts. Still, axonal regeneration did not occur over longer (> 3 cm) distances. One problem may be that a growth-promoting environment not only includes physical cues but also a rich spectrum of different growth factors only provided by reactive Schwann cells. In the current study, we investigated whether a hybrid graft consisting of first-generation autologous Schwann cells seeded onto an acellular auto- or homograft can aid regeneration across a critical nerve defect in a rat model. In this paradigm, Schwann cells were not expanded in vitro but harvested from the proximal stump neuroma at the time of reconstruction and seeded into either an acellular homo- or autograft. Regeneration was then quantitated with functional muscle testing, regular histology, histomorphometry, and retrograde tracing techniques 12 weeks after reconstruction. Results showed successful regeneration over the entire distance regardless of whether Schwann cells were transplanted onto auto- or homologous acellular matrix. Schwann cells did populate both grafts; however, only sensory axons persisted through the entire distance. The functional outcome was dismal with no motor and poor sensory recovery. Control group C with homologous matrix only without Schwann cells showed no signs of directed axonal regeneration. Control group D with autologous reverse graft showed excellent recovery, as was expected. The present experiment sought to create a hybrid graft where the proximal stump neuroma is used as a biological resource for autologous Schwann cells that are seeded unto an acellular matrix, thus providing both physical and chemical support to regenerating axons. The results are encouraging in that successful regeneration was observed over the entire distance; however, only sensory axons had enough regenerative potential to also make end-organ contact. For motor axons, further refinements in conduit preparation have to be done.

Clinical Application of Pectoral Nerve Transfers in the Treatment of Traumatic Brachial Plexus Injuries

The Journal of Hand Surgery. Sep, 2008  |  Pubmed ID: 18762104

To determine the effectiveness, reliability and donor site morbidity of pectoral nerve transfers in the treatment of brachial plexus lesions.

Sensory Recovery After Decompression of the Distal Pudendal Nerve: Anatomical Review and Quantitative Neurosensory Data of a Prospective Clinical Study

Microsurgery. 2009  |  Pubmed ID: 19274651

Decompression of peripheral nerves at different anatomic sites leads to long-lasting improvement of nerve function. For the pudendal nerve such compression sites have also been described, however, indication for surgical decompression at the dorsal nerve canal, and outcome measures have not been presented. In the following work, we review the detailed anatomy of the pudendal nerve at its passage through the urogenital diaphragm into the base of the penis and present the results of our first five patients.

The Anatomic Basis of the Internal Mammary Artery Perforator Flap: a Cadaver Study

Journal of Plastic, Reconstructive & Aesthetic Surgery : JPRAS. Feb, 2010  |  Pubmed ID: 19121988

The perforating branches of the internal mammary artery have recently been described as recipient vessel for free-tissue transfer breast reconstruction. However, reports on perforator flaps based on these vessels are rare. The aim of this study was to investigate the vascular basis of the internal mammary artery perforator (IMAP) flap and to describe the location and size of the individual flaps.

Bridging Peripheral Nerve Defects Using a Single-fascicle Nerve Graft

Plastic and Reconstructive Surgery. Oct, 2011  |  Pubmed ID: 21921762

The criterion standard of nerve reconstruction is an autologous nerve graft, identical in cross-section to the severed nerve stumps. This study investigates single-fascicle nerve transplantation to bridge nerve defects.

Prospective Evaluation of a Single-sided Innervated Gluteal Artery Perforator Flap for Reconstruction for Extensive and Recurrent Pilonidal Sinus Disease: Functional, Aesthetic, and Patient-reported Long-term Outcomes

World Journal of Surgery. Sep, 2012  |  Pubmed ID: 22552500

Treating large and extensive pilonidal sinus disease is a challenging task. Long-term reports on flaps suitable for coverage of large, wide, local-excision defects are sparse. We prospectively evaluated data with a minimum 1-year follow-up of the use of a single-sided, innervated, superior gluteal artery perforator flap.

Reanimation of the Paralyzed Face: Radial Forearm-pronator Quadratus Muscle Flap

JAMA Facial Plastic Surgery. Sep-Oct, 2013  |  Pubmed ID: 23828014

Birth Brachial Plexus Palsy Caused by Cervical Rib

Journal of Plastic, Reconstructive & Aesthetic Surgery : JPRAS. Jul, 2014  |  Pubmed ID: 24630141

The Extraction of Neural Information from the Surface EMG for the Control of Upper-limb Prostheses: Emerging Avenues and Challenges

IEEE Transactions on Neural Systems and Rehabilitation Engineering : a Publication of the IEEE Engineering in Medicine and Biology Society. Jul, 2014  |  Pubmed ID: 24760934

Despite not recording directly from neural cells, the surface electromyogram (EMG) signal contains information on the neural drive to muscles, i.e., the spike trains of motor neurons. Using this property, myoelectric control consists of the recording of EMG signals for extracting control signals to command external devices, such as hand prostheses. In commercial control systems, the intensity of muscle activity is extracted from the EMG and used for single degrees of freedom activation (direct control). Over the past 60 years, academic research has progressed to more sophisticated approaches but, surprisingly, none of these academic achievements has been implemented in commercial systems so far. We provide an overview of both commercial and academic myoelectric control systems and we analyze their performance with respect to the characteristics of the ideal myocontroller. Classic and relatively novel academic methods are described, including techniques for simultaneous and proportional control of multiple degrees of freedom and the use of individual motor neuron spike trains for direct control. The conclusion is that the gap between industry and academia is due to the relatively small functional improvement in daily situations that academic systems offer, despite the promising laboratory results, at the expense of a substantial reduction in robustness. None of the systems so far proposed in the literature fulfills all the important criteria needed for widespread acceptance by the patients, i.e. intuitive, closed-loop, adaptive, and robust real-time ( 200 ms delay) control, minimal number of recording electrodes with low sensitivity to repositioning, minimal training, limited complexity and low consumption. Nonetheless, in recent years, important efforts have been invested in matching these criteria, with relevant steps forwards.

Noninvasive, Accurate Assessment of the Behavior of Representative Populations of Motor Units in Targeted Reinnervated Muscles

IEEE Transactions on Neural Systems and Rehabilitation Engineering : a Publication of the IEEE Engineering in Medicine and Biology Society. Jul, 2014  |  Pubmed ID: 24760935

Targeted muscle reinnervation (TMR) redirects nerves that have lost their target, due to amputation, to remaining muscles in the region of the stump with the intent of establishing intuitive myosignals to control a complex prosthetic device. In order to directly recover the neural code underlying an attempted limb movement, in this paper, we present the decomposition of high-density surface electromyographic (EMG) signals detected from three TMR patients into the individual motor unit spike trains. The aim was to prove, for the first time, the feasibility of decoding the neural drive that would reach muscles of the missing limb in TMR patients, to show the accuracy of the decoding, and to demonstrate the representativeness of the pool of extracted motor units. Six to seven flexible EMG electrode grids of 64 electrodes each were mounted over the reinnervated muscles of each patient, resulting in up to 448 EMG signals. The subjects were asked to attempt elbow extension and flexion, hand open and close, wrist extension and flexion, wrist pronation and supination, of their missing limb. The EMG signals were decomposed using the Convolution Kernel Compensation technique and the decomposition accuracy was evaluated with a signal-based index of accuracy, called pulse-to-noise ratio (PNR). The results showed that the spike trains of 3 to 27 motor units could be identified for each task, with a sensitivity of the decomposition > 90%, as revealed by PNR. The motor unit discharge rates were within physiological values of normally innervated muscles. Moreover, the detected motor units showed a high degree of common drive so that the set of extracted units per task was representative of the behavior of the population of active units. The results open a path for a new generation of human-machine interfaces in which the control signals are extracted from noninvasive recordings and the obtained neural information is based directly on the spike trains of motor neurons.

Multiregion Thermal Sensitivity Mapping of the Hand

Journal of Plastic, Reconstructive & Aesthetic Surgery : JPRAS. Nov, 2014  |  Pubmed ID: 25082332

Previous neurophysiological studies of discrete hand regions have suggested the dorsum to be more sensitive to temperature changes than the palmar surface, but no multiple-region investigation of the corresponding dorsal and palmar regions has been performed. This study aimed to investigate whether the dorsum of the hand is more sensitive to temperature changes than the palm across multiple regions. In 15 healthy human volunteers, cold and warmth detection thresholds were measured in 10 defined areas of the hand using a thermode of 2.56 cm(2). The testing algorithm employed was the Method of Limits with a baseline temperature of 32 °C and a rate of change of 1°/s. In five subjects, cold-pain and heat-pain thresholds were also measured. All dorsal regions were significantly more sensitive to cold than equivalent palmar areas. Differences in warmth thresholds were not uniform but, overall, dorsal sensitivity was significantly higher. This study finds that the dorsal aspect of the hand was more sensitive to temperature changes than the palm, with higher sensitivity to painful thermal stimuli.

Bionic Reconstruction to Restore Hand Function After Brachial Plexus Injury: a Case Series of Three Patients

Lancet (London, England). May, 2015  |  Pubmed ID: 25724529

Brachial plexus injuries can permanently impair hand function, yet present surgical reconstruction provides only poor results. Here, we present for the first time bionic reconstruction; a combined technique of selective nerve and muscle transfers, elective amputation, and prosthetic rehabilitation to regain hand function.

Immunological Blockade of Adipocyte Inflammation Caused by Increased Matrix Metalloproteinase-cleaved Osteopontin in Obesity

Obesity (Silver Spring, Md.). Apr, 2015  |  Pubmed ID: 25776538

Osteopontin (OPN) is upregulated in adipose tissue (AT) in obesity and contributes to subclinical inflammation, adipocyte dysfunction, and insulin resistance. OPN effects can be increased by cleavage by matrix metalloproteinases (MMP). This study aimed at investigating the presence of OPN cleavage products in human AT in obesity and their impact on adipocyte function and immunological blockade of these effects.

Context-Dependent Upper Limb Prosthesis Control for Natural and Robust Use

IEEE Transactions on Neural Systems and Rehabilitation Engineering : a Publication of the IEEE Engineering in Medicine and Biology Society. Jul, 2015  |  Pubmed ID: 26173217

Pattern recognition and regression methods applied to the surface EMG have been used for estimating the user intended motor tasks across multiple degrees of freedom (DoF), for prosthetic control. While these methods are effective in several conditions, they are still characterized by some shortcomings. In this study we propose a methodology that combines these two approaches for mutually alleviating their limitations. This resulted in a control method capable of context-dependent movement estimation that switched automatically between sequential (one DoF at a time) or simultaneous (multiple DoF) prosthesis control, based on an online estimation of signal dimensionality. The proposed method was evaluated in scenarios close to reallife situations, with the control of a physical prosthesis in applied tasks of varying difficulties. Test prostheses were individually manufactured for both able-bodied and transradial amputee subjects. With these prostheses, two amputees performed the Southampton Hand Assessment Procedure (SHAP) test with scores of 58 and 71 points. The 5 able-bodied individuals performed standardized tests, such as the box█ and clothes pin test, reducing the completion times by up to 30%, with respect to using a state-of-the-art pure sequential control algorithm. Apart from facilitating fast simultaneous movements, the proposed control scheme was also more intuitive to use, since human movements are predominated by simultaneous activations across joints. The proposed method thus represents a significant step towards intelligent, intuitive and natural control of upper limb prostheses.

Diffusion Tensor Tractography for the Surgical Management of Peripheral Nerve Sheath Tumors

Neurosurgical Focus. Sep, 2015  |  Pubmed ID: 26323819

OBJECT Peripheral nerve sheath tumors (PNSTs) are uncommon but bear a significant risk of malignancy. High-resolution MRI is the standard technique for characterizing PNSTs. However, planning the appropriate extent of resection and subsequent reconstructive strategies is highly dependent on the intraoperative findings because preoperative MRI evaluation can be insufficient. Diffusion tensor tractography (DTT) represents a recently developed advanced MRI technique that reveals the microstructure of tissues based on monitoring the random movement of water molecules. DTT has the potential to provide diagnostic insights beyond conventional MRI techniques due to its mapping of specific fibrillar nerve structures. Here, DTT was applied to evaluate PNSTs and to examine the usefulness of this method for the correct delineation of tumor and healthy nerve tissue and the value of this information in the preoperative planning of surgical interventions. METHODS In this prospective study, patients with the clinical symptoms of a PNST were investigated using DTT 3-Tesla MRI scans. Image data processing and tractography were performed using the FACT (fiber assessment by continuous tracking) algorithm and multiple-regions-of-interest approach. The surgical findings were then compared with the results of the DTT MRI scans. Preoperative fascicle visualization and the correlation with the intraoperative findings were graded. RESULTS In a 21-month period, 12 patients with PNSTs were investigated (7 female and 5 male patients with a mean age of 46.2 ± 19.2 years). All patients underwent surgical removal of the tumor. Schwannoma was the most common benign histopathological finding (n = 7), whereas 2 malignant lesions were detected. In 10 of 12 patients, good preoperative nerve fascicle visualization was achieved using DTT scans. In 9 of 10 patients with good preoperative fascicle visualization, good intraoperative correlation between the DTT scans and surgical anatomy was found. CONCLUSIONS DTT properly visualizes the peripheral nerve fascicles and their correct anatomical relation to PNST. DTT represents a promising new method for the preinterventional planning of nerve tumor resection.

Prosthesis Control with an Implantable Multichannel Wireless Electromyography System for High-Level Amputees: A Large-Animal Study

Plastic and Reconstructive Surgery. Jan, 2016  |  Pubmed ID: 26710019

Myoelectric prostheses lack a strong human-machine interface, leading to high abandonment rates in upper limb amputees. Implantable wireless electromyography systems improve control by recording signals directly from muscle, compared with surface electromyography. These devices do not exist for high amputation levels. In this article, the authors present an implantable wireless electromyography system for these scenarios tested in Merino sheep for 4 months.

Automated Muscle Fiber Type Population Analysis with ImageJ of Whole Rat Muscles Using Rapid Myosin Heavy Chain Immunohistochemistry

Muscle & Nerve. Aug, 2016  |  Pubmed ID: 26788932

Skeletal muscle consists of different fiber types which adapt to exercise, aging, disease, or trauma. Here we present a protocol for fast staining, automatic acquisition, and quantification of fiber populations with ImageJ.

Motor Unit Characteristics After Targeted Muscle Reinnervation

PloS One. 2016  |  Pubmed ID: 26901631

Targeted muscle reinnervation (TMR) is a surgical procedure used to redirect nerves originally controlling muscles of the amputated limb into remaining muscles above the amputation, to treat phantom limb pain and facilitate prosthetic control. While this procedure effectively establishes robust prosthetic control, there is little knowledge on the behavior and characteristics of the reinnervated motor units. In this study we compared the m. pectoralis of five TMR patients to nine able-bodied controls with respect to motor unit action potential (MUAP) characteristics. We recorded and decomposed high-density surface EMG signals into individual spike trains of motor unit action potentials. In the TMR patients the MUAP surface area normalized to the electrode grid surface (0.25 ± 0.17 and 0.81 ± 0.46, p < 0.001) and the MUAP duration (10.92 ± 3.89 ms and 14.03 ± 3.91 ms, p < 0.01) were smaller for the TMR group than for the controls. The mean MUAP amplitude (0.19 ± 0.11 mV and 0.14 ± 0.06 mV, p = 0.07) was not significantly different between the two groups. Finally, we observed that MUAP surface representation in TMR generally overlapped, and the surface occupied by motor units corresponding to only one motor task was on average smaller than 12% of the electrode surface. These results suggest that smaller MUAP surface areas in TMR patients do not necessarily facilitate prosthetic control due to a high degree of overlap between these areas, and a neural information-based control could lead to improved performance. Based on the results we also infer that the size of the motor units after reinnervation is influenced by the size of the innervating motor neuron.

Improving Arm Function by Prosthetic Limb Replacement in a Patient with Severe Arthrogryposis Multiplex Congenita

Journal of Rehabilitation Medicine. Oct, 2016  |  Pubmed ID: 27534547

In patients with severe bilateral congenital arm deficiencies, even simple activities of daily living, such as feeding, may be major challenges. We report here a case of a patient with arthrogryposis multiplex congenita affecting all 4 extremities, who underwent prosthetic replacement after elective transhumeral amputation of his right functionless arm.

Combining Two Open Source Tools for Neural Computation (BioPatRec and Netlab) Improves Movement Classification for Prosthetic Control

BMC Research Notes. Aug, 2016  |  Pubmed ID: 27581624

Controlling a myoelectric prosthesis for upper limbs is increasingly challenging for the user as more electrodes and joints become available. Motion classification based on pattern recognition with a multi-electrode array allows multiple joints to be controlled simultaneously. Previous pattern recognition studies are difficult to compare, because individual research groups use their own data sets. To resolve this shortcoming and to facilitate comparisons, open access data sets were analysed using components of BioPatRec and Netlab pattern recognition models.

Functional and Psychosocial Outcomes of Hand Transplantation Compared with Prosthetic Fitting in Below-Elbow Amputees: A Multicenter Cohort Study

PloS One. 2016  |  Pubmed ID: 27589057

Hand-transplantation and improvements in the field of prostheses opened new frontiers in restoring hand function in below-elbow amputees. Both concepts aim at restoring reliable hand function, however, the indications, advantages and limitations for each treatment must be carefully considered depending on level and extent of amputation. Here we report our findings of a multi-center cohort study comparing hand function and quality-of-life of people with transplanted versus prosthetic hands.

Attachment of Upper Arm Prostheses with a Subcutaneous Osseointegrated Implant in Transhumeral Amputees

Prosthetics and Orthotics International. Sep, 2016  |  Pubmed ID: 27638013

The stump-socket interface is of utmost importance for prosthetic function in transhumeral amputees. Stability of this connection may be improved using a newly designed subcutaneous implant.

Elective Amputation and Bionic Substitution Restore Functional Hand Use After Critical Soft Tissue Injuries

Scientific Reports. Oct, 2016  |  Pubmed ID: 27721419

Critical soft tissue injuries may lead to a non-functional and insensate limb. In these cases standard reconstructive techniques will not suffice to provide a useful outcome, and solutions outside the biological arena must be considered and offered to these patients. We propose a concept which, after all reconstructive options have been exhausted, involves an elective amputation along with a bionic substitution, implementing an actuated prosthetic hand via a structured tech-neuro-rehabilitation program. Here, three patients are presented in whom this concept has been successfully applied after mutilating hand injuries. Clinical tests conducted before, during and after the procedure, evaluating both functional and psychometric parameters, document the benefits of this approach. Additionally, in one of the patients, we show the possibility of implementing a highly functional and natural control of an advanced prosthesis providing both proportional and simultaneous movements of the wrist and hand for completing tasks of daily living with substantially less compensatory movements compared to the traditional systems. It is concluded that the proposed procedure is a viable solution for re-gaining highly functional hand use following critical soft tissue injuries when existing surgical measures fail. Our results are clinically applicable and can be extended to institutions with similar resources.

Algorithm for Bionic Hand Reconstruction in Patients with Global Brachial Plexopathies

Journal of Neurosurgery. Jan, 2017  |  Pubmed ID: 28093018

OBJECTIVE Global brachial plexus lesions with multiple root avulsions are among the most severe nerve injuries, leading to lifelong disability. Fortunately, in most cases primary and secondary reconstructions provide a stable shoulder and restore sufficient arm function. Restoration of biological hand function, however, remains a reconstructive goal that is difficult to reach. The recently introduced concept of bionic reconstruction overcomes biological limitations of classic reconstructive surgery to restore hand function by combining selective nerve and muscle transfers with elective amputation of the functionless hand and its replacement with a prosthetic device. The authors present their treatment algorithm for bionic hand reconstruction and report on the management and long-term functional outcomes of patients with global brachial plexopathies who have undergone this innovative treatment. METHODS Thirty-four patients with posttraumatic global brachial plexopathies leading to loss of hand function consulted the Center for Advanced Restoration of Extremity Function between 2011 and 2015. Of these patients, 16 (47%) qualified for bionic reconstruction due to lack of treatment alternatives. The treatment algorithm included progressive steps with the intent of improving the biotechnological interface to allow optimal prosthetic hand replacement. In 5 patients, final functional outcome measurements were obtained with the Action Arm Research Test (ARAT), the Southampton Hand Assessment Procedure (SHAP), and the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. RESULTS In all 5 patients who completed functional assessments, partial hand function was restored with bionic reconstruction. ARAT scores improved from 3.4 ± 4.3 to 25.4 ± 12.7 (p = 0.043; mean ± SD) and SHAP scores improved from 10.0 ± 1.6 to 55 ± 19.7 (p = 0.042). DASH scores decreased from 57.9 ± 20.6 to 32 ± 28.6 (p = 0.042), indicating decreased disability. CONCLUSIONS The authors present an algorithm for bionic reconstruction leading to useful hand function in patients who lack biological treatment alternatives for a stiff, functionless, and insensate hand resulting from global brachial plexopathies.

Game-Based Rehabilitation for Myoelectric Prosthesis Control

JMIR Serious Games. Feb, 2017  |  Pubmed ID: 28183689

A high number of upper extremity myoelectric prosthesis users abandon their devices due to difficulties in prosthesis control and lack of motivation to train in absence of a physiotherapist. Virtual training systems, in the form of video games, provide patients with an entertaining and intuitive method for improved muscle coordination and improved overall control. Complementary to established rehabilitation protocols, it is highly beneficial for this virtual training process to start even before receiving the final prosthesis, and to be continued at home for as long as needed.

Translating Research on Myoelectric Control into Clinics-Are the Performance Assessment Methods Adequate?

Frontiers in Neurorobotics. 2017  |  Pubmed ID: 28261085

Missing an upper limb dramatically impairs daily-life activities. Efforts in overcoming the issues arising from this disability have been made in both academia and industry, although their clinical outcome is still limited. Translation of prosthetic research into clinics has been challenging because of the difficulties in meeting the necessary requirements of the market. In this perspective article, we suggest that one relevant factor determining the relatively small clinical impact of myocontrol algorithms for upper limb prostheses is the limit of commonly used laboratory performance metrics. The laboratory conditions, in which the majority of the solutions are being evaluated, fail to sufficiently replicate real-life challenges. We qualitatively support this argument with representative data from seven transradial amputees. Their ability to control a myoelectric prosthesis was tested by measuring the accuracy of offline EMG signal classification, as a typical laboratory performance metrics, as well as by clinical scores when performing standard tests of daily living. Despite all subjects reaching relatively high classification accuracy offline, their clinical scores varied greatly and were not strongly predicted by classification accuracy. We therefore support the suggestion to test myocontrol systems using clinical tests on amputees, fully fitted with sockets and prostheses highly resembling the systems they would use in daily living, as evaluation benchmark. Agreement on this level of testing for systems developed in research laboratories would facilitate clinically relevant progresses in this field.

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