main topic Wien Klin Wochenschr https://doi.org/10.1007/s00508-019-1518-1 Bionic reconstruction Restoration of extremity function with osseointegrated and mind-controlled prostheses Martin Aman · Christopher Festin · Matthias E. Sporer · Clemens Gstoettner · Cosima Prahm · Konstantin D. Bergmeister · Oskar C. Aszmann Received: 15 December 2018 / Accepted: 25 May 2019 © The Author(s) 2019 Summary received TMR in combination with an osseointegrated Background Loss of an extremity at any level has implant and structured rehabilitation is presented. a major impact on a patient’s life. Using bionic re- Results Using bionic reconstruction, basic hand func- construction, extremity function can be restored and tions can be restored and bimanual dexterity can ex- the patient reintegrated into daily life. Surgical proce- pand the range of daily activities. Besides this ap- dures including selective nerve transfer and anchoring proach to bionic reconstruction, its advantages and of prostheses into bone are combined with structured disadvantages are compared to hand transplantation. rehabilitation and modern prosthetic fitting. The pa- The limitations and perspectives of modern bionic re- tient is thereby able to use the prostheses intuitively construction are also discussed. and with multiple degrees of freedom. Conclusions Bionic reconstruction is a sophisticated Methods This article presents the concept and ap- method for restoring extremity function and nowa- proach for modern bionic reconstruction in detail days can be considered a standard of care for all levels and the relevant literature. The nerve transfer matri- of upper extremity amputations. An interdisciplinary ces for targeted muscle reinnervation (TMR) and the approach and structured rehabilitation are necessary concept of osseointegration to optimally fit a patient to master prosthetic function to ultimately reintegrate with a modern prosthesis are described in detail. As patients into daily life. a clinical example, the case of a patient who suf- fered from traumatic amputation and subsequently Keywords Bionic reconstruction · Interface · Prostheses · Osseointegration · Rehabilitation M.Aman,M.D.·C.Festin·M.E.Sporer,M.D.· Amputation in the past and present C. Gstoettner, M.D. · C. Prahm, M.Sc. · O. C. Aszmann, M.D. () The human upper extremity and especially its most CD Laboratory for the Restoration of Extremity Function, Department of Surgery, Medical University of Vienna, distal part, the hand, is essential for interacting with Vienna, Austria otheur environment. Due to its rich sensorimotor in- [email protected] nervation and the resulting fine motor control, multi- ple degrees of freedom and dexterity, it enables tasks M. Aman, M.D. · M. E. Sporer, M.D. · K. D. Bergmeister, M.D. Ph.D as simple as buttoning a shirt or using a smart phone Division of Biomedical Research, Medical University of to very complex endeavors, such as playing the piano Vienna, Vienna, Austria [1]. The loss of a hand is a tragic event with severe consequences for a person’s physical and psycholog- K. D. Bergmeister, M.D. Ph.D · O. C. Aszmann, M.D. Division of Plastic and Reconstructive Surgery, Medical ical well-being as well as social and work life. It im- University of Vienna, Vienna, Austria pacts a person’s capability to perform activities of daily living, such as personal hygiene, environmental inter- O. C. Aszmann, M.D. action or social interaction. Furthermore, the emo- Christian Doppler Laboratory for Restoration of Extremity Function, Division of Plastic and Reconstructive Surgery, tional burden associated with an amputation can lead Department of Surgery, Medical University of Vienna, to depression as a result of an impaired body image Spitalgasse 23, 1090 Vienna, Austria [2, 3]. Additionally, approximately 70% of amputees K Bionic reconstruction main topic experience phantom limb pain [4]. The majority of over by a truck. He presented at this facility 6 months amputations affect healthy, young male patients and after the accident with a transhumeral amputation, result from high-energy trauma [2, 5, 6]. Consider- moderate phantom limb pain and a neuroma in the ing these demographic data, upper limb loss also has distal stump. He was impaired in his daily life routine severe socioeconomic implications, as many patients and dependent on the help of his wife in all activi- are unable to return to their previous occupation or ties of daily living. He consulted this department to to work in general [7]. regain independence and for reintegration into work. Attempts to replace a missing upper limb and re- After discussing alternative treatment options, such store function can be dated back several centuries. as biological reconstruction, bionic reconstruction Historically, it was done by fitting injured knights and was planned. soldiers with very cumbersome and heavy prosthetic devices such as iron hands. Prostheses that could per- Myoelectric prostheses form intended movement, so-called body-powered prostheses, were first developed in the nineteenth Myoelectric prostheses have been steadily improved century. The World Wars I and II of the following since their introduction in the mid-twentieth century, century led to a massive demand for upper extrem- yet the basic principle of translating muscle electri- ity replacement to help theinnumerabledisabled cal activity into movement has remained the same soldiers. Consequently, considerable refinements [18, 19]. A standard myoelectric prosthesis usually and advancements were developed for body-powered consists of a shaft with a socket, the connection be- prostheses. At the same time, the first externally tween the device and the patient, called the man-ma- powered prostheses, capable of translating residual chine interface, and a robotic hand. Typically, surface muscle electrical activity into movement, were devel- electromyography (EMG) electrodes are embedded in oped. After further improvements, these myoelectric the socket and placed above residual muscles of the prostheses have been clinically used since the 1960s stump. These electrodes record the muscle’s electri- [8]. Nowadays, refined and enhanced versions of both cal activity that the patient can activate voluntarily body-powered and myoelectric prostheses are com- via an amplitude measurement. This is then used monly used in upper extremity reconstruction [9]. to control the prosthetic hand. This so-called con- Furthermore, approximately one third of patients also ventional control represents the most common con- use passive prostheses ranging from cosmetic hands trol scheme. To ensure intuitive prosthetic control, it to prosthetic tools such as hooks or devices designed is desirable to record activity from muscles that are for specific activities [10, 11]. functionally related to the associated movements per- In addition to prosthetic developments, advance- formed by the prosthesis. This may be done by using ments in microsurgery have opened the possibility for the antagonistic flexor and extensor muscles of the upper extremity replantation as a viable treatment op- stump to facilitate closing and opening of the pros- tion for upper extremity amputation since the 1960s. thetic hand [20, 21]. If several residual muscles are Additionally, the development of modern immuno- available, it opens the possibility of controlling multi- suppressive drugs during the 1980s and 1990s in com- ple functionally related degrees of freedoms [22]. If the bination with sophisticated microsurgical techniques number of recordable muscle signals does not meet have made upper extremity transplantation a poten- the requirements to simultaneously control multiple tial treatment option [12–17]. degrees of freedom, the use of sequential or multistate The aim of this work is to demonstrate the ap- controllers to cycle between different functions by co- proach for bionic reconstruction. The nerve trans- contracting a muscle pair poses a viable, yet unintu- fer matrices for targeted muscle reinnervation (TMR) itive and cumbersome alternative [21, 23]. and the concept of osseointegration to optimally fit a patient with a modern prosthesis are described in Man-machine interface detail. As a clinical example the case of a patient who suffered a traumatic transhumeral amputation of the The basis for correct functioning and therefore a ma- left arm and subsequently received TMR in combina- jor influence regarding patient satisfaction and ac- tion with an osseointegrated implant and structured ceptance is a stable, reliable man-machine interface, rehabilitation is presented. Furthermore, the article capable of translating neural information of intended discusses the approach in view of the current litera- movement into prosthetic control signals [24]. From ture and shows future perspectives of modern bionic an engineering point of view, the interface comprises prostheses. all the elements between a machine and a human necessary to translate biological activity into electrical Clinical background part 1 control signals, such as electrodes, wires and proces- sors [25]. Due to its easy application and noninva- The patient (male, 53 years old, married, right- siveness, surface EMG is the most common approach handed) suffered a traumatic amputation of the left used for prosthetic control; however, the recorded upper extremity in a work-related injury by being run signals are greatly influenced by different electrome- Bionic reconstruction K main topic chanical factors such as electrode displacement as and subsequent