Overcoming the effects of facial paralysis is a long process requiring multidisciplinary input, subspecialty expertise and a staged systematic approach. Whether the journey of facial reanimation requires retraining of muscles and nerves or surgery, the aim is to improve symmetry of the face and protect the vitality of the eye surface.
One of the key treatment objectives is to restore the dynamics of the eyebrow-eyelid complex and orbicularis oculi muscle. The orbicularis is a key muscle of the periocular area, responsible for the resting tone and closure of the eyelid. The intricate balance between the action of the orbicularis (a protractor muscle that closes the eyelid) and the levator palpebrae muscle (a retractor muscle that antagonizes the orbicularis by lifting the upper eyelid) is affected by facial palsy at the advantage of the eyelid retractors. As a result impairment of eyelid closure occurs and regular lubrication is essential to maximize the protective barriers of the corneal surface.
Depending on the underlying aetiology and the degree of anticipated neuromuscular recovery, surgical rehabilitation of the periorbital area aims to reinforce the dynamic excursion and closure of the upper and the positional tone of the lower eyelid. Additional interventions can address eyebrow and lower face asymmetries.
The denervation of the orbicularis oculi muscle, can be counterbalanced by weakening the action of its natural antagonist muscles. In the upper eyelid, weakening the levator palpebrae superioris muscle (the muscle that primarily opens the eye) can be achieved nonsurgically or surgically. Botulinum toxins may be selectively injected into this muscle to induce relaxation of the eyelid and thus improve eyelid closure. Surgical weakening of the levator muscle can be performed via a hidden approach from the undersurface of the eyelid: a procedure named transconjuctival recession. Alternatively, placement of a gold or platinum weight through a small incision within the eyelid crease can improve the dynamic excursion of the upper eyelid and protection of the corneal surface.
Additional reinforcement of the tone of the lower eyelid by strengthening the ligaments at the corner of the eye (lateral canthal resuspension or canthoplasty) can improve the position the position and the interface with the ocular surface. Volumizing agents like hyaluronic acid gel injections may play an important role in the early stages when surgery is not recommended. Placement of the filler in the upper eyelid and within the plane of the levator muscle provides a “gold weight” effect and counterbalances the retraction of the upper eyelid. For patients with transient facial palsy with good prognosis for recovery of facial muscle function, hyaluronic acid gel injection is an elegant way to protect the eye and avoid surgery.
In similar fashion, injections of hyaluronic acid gel within the lower eyelid complex can improve the position of the eyelid margin, ameliorate asymmetry, and most importantly minimize exposure of the corneal surface and lagophthalmos. Botulinum toxin type A (BTTA) injections may have an important role in balancing the action of overacting muscles and symptoms of synkinesis. Synkinesis is the result of abnormal facial nerve regeneration and manifests as abnormal synchronization of facial movements, where muscles other than those intended contract together during specific actions of the face. The most common effect of synkinesis is when patients experience eye closure or twitching while smiling or chewing.
BTTA injections can relax the unwanted muscle movements on the normal side of the face and reduce tension in areas of the face that are hyperactive due to synkinesis. Treatment of synkinesis in conjunction with re-education of muscles and nerves can be initiated at any time after symptom onset and augment results of medical and surgical therapies.