Structured Motor Rehabilitation After Selective Nerve Transfers

After nerve injuries and selective nerve transfers, structured rehabilitation is needed to facilitate motor recovery. This protocol is designed to guide therapists and patients through this long-lasting process. Using surface EMG biofeedback, active rehabilitation may be started earlier than with conventional therapy.

Additionally, this technique supports the patient's understanding of exercises during training. To begin this procedure, use the first post surgical consultation or therapy session to thoroughly explain the type of injury and the performed surgery in detail. Visualize the nerve transfers that were performed on an anatomical figure or printout.

Therapy interventions in this demonstration are meant for patients who underwent an Oberlin's nerve transfer. Then, explain how the altered neural pathway initially requires considering a nerve's original movement pattern. First, prepare cards showing left and right extremities and show them to the patient in a random order.

Ask the patient if a left or right extremity is shown. While of a speed of approximately two seconds per card is normal, give the patient at least 15 seconds to answer if needed. Give the patient feedback and if necessary, time to understand why the answer was wrong.

Next, set up the mirror therapy by placing a standing mirror or mirror box in front of the therapist and patient. Place the mirror on a desk for the upper extremity or on the floor for the lower extremity. Explain that the mirror therapy works by making use of the reflection of the sound side to create the image of the simultaneous movement of the sound side and denervated extremity.

Briefly demonstrate this with the therapist's own corresponding extremity. Place the mirror medially in front of the patient in a way that allows them to see the reflection of the sound side exactly where the injured extremity is expected. Make sure that the entire injured extremity is covered by the mirror and cannot be seen by the patient.

Ask the patients which movements they can easily imagine and instruct them to perform these movements with the sound side while looking at the mirror. Then, instruct the patient to move both sides for five to 10 minutes. Explain that the injured side will not move, but that it is still important to generate the illusion of simultaneous movement of both sides.

Begin this part of the rehabilitation as soon as the first volitional contraction of the reinnervated muscle can be detected, which can usually be expected within three to five months after surgery. Set up a system for EMG biofeedback by unpacking it on a table, making sure to plug in all cables, and press the Power button. Ask the patient to think of movements that the donor nerves were originally responsible for and palpate the recipient muscle.

Then, place a surface EMG electrode on the exact position where muscle contraction can be palpated. Even if no movement can be palpated, check for the EMG activity regularly within the first three to six months after surgery. If EMG activity on this position cannot be confirmed, slightly change the position of the electrode and try other motor commands related to the donor nerve.

Otherwise, continue with the interventions for cortical activation and test again after a few weeks. If EMG activity can be detected, make sure the patient is comfortably seated and instruct them to think of movement patterns related to the donor nerve while picking up surface EMG signals from the recipient muscle. If a system with the possibility to adjust signal gains is used, set it up in a way that the signal amplitude is high enough to be easily observed.

As soon as the patient can repeatably activate the muscle, ask them to fully relax after muscle activation, which corresponds to EMG amplitudes close to zero. Ask the patient to repeatedly activate the muscle and fully relax it. Try different movement cues and electrode positions in order to find the highest amplitude.

After finding a good combination, maintain it the rest of the session. As soon as the patient feels confident with the surface EMG setup, introduce motor commands including both the activation of the donor nerve and the actual function of the recipient muscle. As soon as the muscle is strong enough to overcome gravity or the resistance of antagonistic muscles and joint stiffness, focus therapy on relearning the original movement pattern of the recipient nerve.

Encourage the patient to slightly activate their recipient muscle without the movement in the muscles originally innervated by the donor nerve. Support this by using surface EMG biofeedback with two channels. Place one bipolar electrode on the skin above the reinnervated muscle and put the other one above the skin on the original donor nerve muscle.

This allows the patient to simultaneously see the activation of both muscles. Encourage the patient to activate the recipient muscle and ensure that the donor muscle is relaxed with a low EMG signal amplitude. Let the patient know that signal separation is usually easier with slight muscle activation and that unwanted co-contraction of both muscles is common at the beginning of training.

Using the same surface EMG setup, ask the patient to activate the donor muscle without the activation of the reinnervated muscle and monitor for desirable or undesirable strategies that result in better or worse separation of signals. Encourage strategies that support signal separation. If both signals can be separated with slight muscle contractions, ask the patient to perform stronger contractions.

As soon as good signal separation while using EMG biofeedback can be observed, ask the patient to perform separated donor and recipient movements without feedback. With increased motor function, encourage the patient to do more complex tasks including increased muscle force or improved precision. Finally, focus on activities of daily living and those needed in the patient's home, work environment, and when performing sports.

In this study, a program is outlined for motor rehabilitation after complex peripheral nerve injuries. Five patients participated and their characteristics, including injury and the performed surgical reconstruction, are shown here. All of the included patients suffered severe brachial plexus injuries.

Thus motor recovery without surgical intervention was deemed unlikely and direct nerve suture was not possible in any of the cases. The performed nerve transfers were chosen depending on the intact anatomy and where possible nerve transfers from agonistic muscles were performed. This was done to reduce the cognitive load during motor relearning.

All of the patients are seen to have an improved shoulder and elbow function after rehabilitation allowing them to flex the arm against gravity. Two of the patients with an Oberlin's ulnar nerve transfer regained full elbow flexion strength. In this video we displayed the various steps of rehabilitation using the example of an Oberlin's nerve transfer.

Other movement cues need to be given for different nerve transfers. In line with clinical reasoning, other therapeutic techniques can be used alongside the ones presented here. We recommend supplementing the protocol to treat any additional injuries or impairments.