62.1 Introduction

Patients consistently report facial paralysis as one of the most debilitating complications after vestibular schwannoma resection.s. Literatur ^,​ s. Literatur Far from being a simple cosmetic issue, facial paralysis can result in significant functional and psychological consequences, substantially decreasing quality of life. Facial muscles play a unique role in the human body. Simply stated, their purpose is to move the facial skin in various directions, producing a wide variety of movement patterns used primarily for nonverbal communication, eye closure, and oral motor functions. The subtleties of human expression require a delicate balance of activity among multiple facial muscles. Acutely, injury to the facial nerve causes a readily recognizable flaccid paralysis. In delayed recovery, this may be followed by aberrant neural reinnervation causing inappropriate movement. Termed “synkinesis,” this condition is less common and can go unrecognized by patients as well as medical professionals. What can deceptively appear to be weakness in the synkinetic face may in fact be abnormal cocontraction of opposing musculature limiting normal movement patterns.

For the patient with incomplete recovery, facial neuromuscular retraining (fNMR) offers a nonsurgical approach to rehabilitation for restoring and refining functional facial expression.

The objectives of this chapter are to (1) provide an overview of fNMR, highlighting the differences between fNMR and traditional therapy methods; (2) explain specific therapeutic approaches for treating flaccidity, paresis, and synkinesis with timelines for referral; (3) discuss the adjunct of Botulinum toxin (Botox) to fNMR to optimize outcomes in synkinesis.

62.2 Facial Neuromuscular Retraining

Facial neuromuscular retraining is a specific subset of occupational and physical therapy created for improving functional outcomes in patients with facial paralysis, paresis, and/or synkinesis after facial nerve injury. This comprehensive clinical program was first described by Balliet and colleagues in 1982, who reported improved function in patients more than 2 years after facial nerve injury.s. Literatur Acquisition of new motor behaviors was attributed to brain plasticity, the capacity of the central nervous system to modify its organization, resulting in lasting functional change.s. Literatur

Current programs are based largely on the works of Balliet et al,s. Literatur ^,​ s. Literatur Diels,s. Literatur Beurskens,s. Literatur Ross et al,s. Literatur and Coulson,s. Literatur the most salient features being detailed patient education, individualized program development using a wide variety of motor learning techniques, and active patient participation.

To address the complexities of facial movement, the fNMR process identifies neuromuscular firing and sequencing abnormalities and treats them by focusing on improving coordination between muscles as opposed to simply increasing their strength. The ability to create a myriad of expressions requires subtlety, accuracy, and precise control of the 20 plus pairs of facial muscles. fNMR employs modalities such as surface electromyography and proprioceptive, sensory, and mirror feedback to teach subtle, precise, coordinated movement patterns to achieve that aim. Techniques are based on characteristics unique to the facial neuromuscular system: lack of muscle spindles,s. Literatur resistance to fatigue and atrophy,s. Literatur small motor units,s. Literatur and the presence of emotional as well as volitional, neural inputs.s. Literatur These attributes distinguish facial muscles from other skeletal muscles and are the basis for the distinct techniques that make fNMR effective.

Facial paralysis is rare in the practice of rehabilitation medicine, one of few peripheral nerve (lower motor neuron) injuries requiring intervention. There is little training in its effective management. In contrast to the precise, functional patterns that exemplify fNMR, general therapy techniques may include generic exercises and/or electrical stimulation, both of which may be contraindicated in treating this population.s. Literatur

Acutely after vestibular schwannoma resection, the absence of muscle contraction is due to lack of neural signal. Like flipping a switch to light the bulb on a lamp that is unplugged, no amount of exercise will trigger the facial muscles to contract without a functional electrical circuit.

Electrical stimulation continues to be widely used despite evidence suggesting it may interfere with neural regeneration after peripheral nerve injury.s. Literatur ^,​ s. Literatur Clinical experience suggests that patients who receive it acutely may have more synkinesis and mass action than those who do not. Because its application coincides with the spontaneous recovery period, improvements can erroneously be attributed to the stimulation rather than the natural course of recovery. In the synkinetic face, electrical stimulation and maximum effort exercises can reinforce abnormal movements.

Typical duration of fNMR is 18 months to 3 years. Treatment schedules vary widely depending on multiple factors. Local patients may be scheduled once a month, while those traveling a distance might return every 6 months. Home practice hours between clinic visits far exceed billed-therapy hours resulting in a cost-effective program that greatly amplifies the effect of treatment. This process empowers patients to assume control of their own recovery.

62.3 Patient Selection and Evaluation

Criteria for patient selection include neural supply or reanimation, motivation, and adequate cognition. Elements of patient evaluation include:

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  Medical history.

  
  
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  Detailed motion analysis during clinical observation.

  
  
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  House–Brackmann facial grading scale.

  
  
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  Sunnybrook facial grading system.

  
  
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  Synkinesis Assessment Questionnaire (SAQ).

  
  
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  Facial Clinimetric Evaluation (FaCE) scale.

  
  
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  Standardized video and photographic evaluations.

Evaluation results, prognosis, and course of treatment are discussed with the patient and used to develop goals and a comprehensive treatment plan.