A MATTER OF TIMING AND BRAIN-HAND INTERACTION
– Written by Birgitta Rosén and Anders Björkman, Sweden
INTRODUCTION
Rehabilitation following a hand injury is a teamwork involving a close cooperation between patient, surgeon, occupational therapist, physiotherapist and sometimes also a counsellor (Figure 1). It is important to acknowledge that surgery is only the first part of the treatment. A perfect surgical result can be completely ruined if it is not followed by correct rehabilitation at the right time and with appropriate intensity. To achieve this, hand surgeons and therapists should use an evidence-based process to attain optimal management of individual patients where patient goals and values, experience, and research evidence, are integrated to make the best decisions when selecting a diagnostic test, or an intervention1.
During the rehabilitation process it is important to take several aspects into account such as; which structures in the hand are injured or damaged, the functions of the injured hand and the patients´ situation, capacity and understanding of the situation and the possibilities to perform the rehabilitation2. Psychological stress with fear, anger and helplessness is common following a hand injury and this can affect the result. Paul Brand, a pioneer hand surgeon emphasized the impact of attitudes in the rehabilitation process and the importance to actively implement positive factors like confidence, competence and faith in the process3. Thus, it is important to adopt a holistic perspective i.e. to offer a basic physiological as well as psychological treatment4.
THE HAND AND THE BRAIN
The human hand is capable of both power grips as well as coordinated precision movements. Much of our personality also lay in the gestures and movements of the hand. In addition, the hands´ subtle sensibility can help us experience and communicate with the surrounding world. Sensory information from receptors in the hand are sent to the primary somatosensory cortex in the brain where the information is processed, and we become aware of it. The muscles in the hand and arm are controlled by the motor network. This network includes several different areas in the brain, including the primary somatosensory cortex, working together to produce complex signals to the different muscles. One of the more important parts of the motor network is the primary motor cortex located in the pre-central gyrus. The body surface and muscles are not equally represented in the somatosensory and motor cortex in the brain. Instead, the hand and face including the tongue are represented in the somatosensory and motor cortex by very large areas, reflecting the large number of nerve cells needed for fine motor control and somatosensory processing in these body parts compared to e.g. the legs or torso. The cerebral representation of different body-parts can be illustrated in a homunculus (Figure 2). In addition, there is a delicate interaction between the motor and sensory systems. We are often not aware of the complexity in nervous system controlling the hand. However, this complexity become apparent when the hand is injured. Understanding the sensory-motor interaction in the hand and arm are important in understanding disorders and their treatment.
The brain is dynamic, it constantly changes and adopts based on the afferent sensory input, training and injuries - an ability called plasticity. The plastic capacity decrease with age but is never lost. An injury to a nerve in the hand or arm results in profound changes in sensory-motor areas in the brain5,6. But, all hand injuries, not only nerve injuries, that limit movements, lead to decreased sensory input to the brain and this in turn leads to plastic changes in sensory-motor areas in the brain. The brains´ plastic capacity also opens possibilities. Plasticity can be guided to support functions that has been damaged or lost this is termed “guided plasticity”7. During the last decades our knowledge in neurobiology has increased enormously which has made it possible to design a large number of different treatment strategies where guided plasticity is used in patients with hand injuries8.
One example of guided plasticity is mirror visual feed-back (MVF) where an illusion of a healthy hand is created on the place of the injured hand, using a mirror (Figure 3). This will activate the “correct” areas (neurons) in the brain thus facilitating recovery.
Following an injury, the hand is often immobilized. However, it is well known that immobilization of a hand result in cerebral changes where the neurons in the sensory-motor areas in the brain, that usually process information to or from the immobilized area, start processing information to and from other parts of the body9. The longer the time in immobilization the more hard-wired are the cerebral changes10,11. Clinically these cerebral changes are evident as uncoordinated movement and changed sensibility when the patient is mobilized. Thus, it is important to keep the immobilization time as short as possible and to stimulate the neurons in the sensory-motor cortex that are left without stimulation during the immobilization. Several different guided plasticity techniques have been advocated to stimulate the brain during immobilization such and sensory/motor observation and sensory/motor imaginary10,12-14.
THE GLIDING SURFACES OF THE HAND
The aim of hand rehabilitation following an injury or disease is to restore function and the ability to be active and participate in society. Surgery is the beginning of a process where the next phase – rehabilitation – is of great importance for reaching a good hand function.
Prehension is basically the thumb in opposition against the four fingers in numerous of combinations which allow for a functioning hand in daily activities. The anatomy of the hand is complex and is based on an interaction between a large number of moving anatomical structures15. There is a delicate interplay between the intrinsic muscles for precision and coordination, and extrinsic muscles for strength and larger range of motions. To restore as well as to prevent the sliding surfaces, that surround most of the structures in the hand, from adhesions following injury or surgery is a primary goal in hand surgery and hand rehabilitation2. Following an injury or surgery these gliding surfaces are put out of play and scarring and edema between the different tissue layers can cause adhesions between the gliding surfaces. This is counteracted by a gentle surgical technique and early mobilization in combination with efforts to reduce edema. Following surgery to the hand it is important to start mobilization of the shoulder as early as possible. In addition, mobilization of the fingers should also be started as early as possible given the type of surgery. It is a fine balance between too gentle mobilization – and thus not getting any effect out of the rehabilitation – and being too intense, causing micro-ruptures and bleedings with secondary scarring.
During rehabilitation it is important to reduce edema by using light compression and exercises. In order to facilitate the rehabilitation, the cast/bandage should leave uninjured parts free to move. At follow ups the exercises are gradually upgraded individually. Most injured anatomical structures can withstand full load after three months. The hand therapist (specialized physiotherapist or occupational therapist) should guide the patient with knowledge and appropriate training tools and give tips on compensatory strategies and assistive devises. A conscious use of the hand in daily activities, in appropriate doses facilitate rehabilitation.
ORTHOSES
An orthosis is a custom fabricated device that can permanently substitute a lost function or be used during a limited timespan to facilitate the healing process2. An orthosis can also alleviate pain and restore function. It is important to consider using an orthosis early in the rehabilitation process to enhance early gliding of the tissue while protecting reconstructed structures.
There are static and dynamic orthoses. A static orthosis at night can for example relieve the median nerve and thus decrease symptoms of carpal tunnels syndrome. A dynamic, individually costumed orthosis can be an important part in the treatment of, for example, a stiff joint.
The design and fabrication of hand and upper extremity orthotic devices require an in-depth knowledge of anatomy and pathology, as well as knowledge about the healing process and required anatomical positions for the specific situation. Hand therapists are uniquely qualified to design, apply, monitor, and modify orthotic devices as part of the rehabilitation plan.
EARLY START OF REHABILITATION
Attention of the gliding surfaces and an early start of rehabilitation is often essential for a good result following a hand injury. With this said, when designing the rehabilitation, it is important to consider how the different tissues in the hand heal. Some may heal quickly whereas others may take very long time to heal. Furthermore, the type of surgical technique used is a factor affecting how fast for example a tendon injury or a fracture can be mobilized. A tendon that is repaired with a tendon weave or multiple core sutures or a fracture that is stabilized with a plate and several screws can often be mobilized fast2,16. An orthosis can substitute a cast in order to promote early mobilization. Today early, within days after surgery, mobilization is standard procedure following repair of fractures and tendon injuries (Figure 4). Long immobilization time often lead to problems in the rehabilitation process and thus it is important that the surgeon as far as possible use a surgical technique, i.e. suture technique and osteosynthesis, that allow for rapid mobilization16,17. In addition, adequate post-operative pain control is important to facilitate the early mobilization.
When considering nerve injuries early rehabilitation is important due to other aspects. Within hours after a nerve injury there are profound changes in the cerebral areas processing sensory and motor information from and to the injured nerve5. Today there is solid scientific evidence that early rehabilitation improve outcome following nerve injury in the hand and arm8. Rehabilitation using guided plasticity aim to activate the neurons in sensory and motor areas in the brain that usually respond to the injured nerve and thus prepare neurons in these areas to when the injured nerve has regenerated and start functioning again. Thus, guided plasticity will make the recovery process faster and more accurate8.
THE THERAPIST AS TEACHER AND COACH
The physiotherapist and occupational therapist function as coaches for the patient during the rehabilitation period. In this coaching role several aspects should be included apart from designing and monitoring the individual mobilization and training program such as informing the patient about the injury and the rehabilitation as well as motivating the patient to be active in the rehabilitation process.
The outcome depends on how the patient adhere to and follow the training program designed for them. In many conditions in hand rehabilitation after surgery, frequent training sessions every day are necessary for physiological as well as cognitive reasons. Patients behavior during rehabilitation is of a complex nature and many individual factors can influence the engagement18. A patient with knowledge and understanding of the consequences of an injury is more likely to take more active part in their rehabilitation, endure some pain after exercises and adhere to the necessary training. When the therapist instructs the patient in a way that is congruent with the patients preferred manner of learning, the likelihood of the information being internalized by the patient increases. This in turn empowers the patient to find their own strategies to cope with the pain and discomfort that many can experience. Not everyone succeeds in their training, for reasons that may be connected to lack of adherence, sense of meaningfulness, motivation or the fact that we have different learning styles. A clear connection between the training and daily activities – occupation-based interventions – is an important factor for adherence to the suggested treatment18,19.
Furthermore, knowledge about ergonomics is important to prevent overuse injuries of the un-injured structures or un-injured side.
FOLLOW-UP AND DOCUMENTATION
Regular follow-ups using standardized, evidence-based outcome instruments are imperative to assess function and to give feed-back to the patient and team treating the patient. The approach to evaluation of treatment is a combination of the so-called bottom-up (foundational factors) and top-down (role competency and meaningfulness) approach, in an evidence based perspective. In order to achieve an understanding of the patients´ limitations, and strengths.
Assessments of specific functions as well as patient rated outcome measure (PROMs) to capture a patients´ perception of their own daily life function and health, have both a place in the follow-up20.
An example of a structural follow-up can be found on the Swedish hand registry homepage (www.hakir.se).
Birgitta Rosén O.T., Ph.D.
Senior Lecturer
Department of Translational Medicine – Hand Surgery, Malmö
Lund University
Sweden
Anders Björkman M.D., Ph.D.
Professor and Senior Consultant in Hand Surgery
Department of Hand Surgery, Institute of Clinical Sciences
Sahlgrenska Academy, University of Gothenburg
Sahlgrenska University Hospital
Gothenburg, Sweden
Contact: anders.bjorkman@med.lu.se
References
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Header image by Frankfort Convention Center (Cropped)