Craniofacial Muscles

15 Facial Nerve Innervation and Facial Palsies
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lower eyelids; the midface and mouth; and lower lip. In general, we have found that
patients under 10 years get the best results with functional muscle transfer reconstructions.
They often achieve spontaneous smiles, and we believe this correlates
with their nerve regeneration capacity. In patients over the age of 55 years, the
bene fi t from a free-functioning muscle transplant procedure may be less predictable.
In these cases, we opt for either a simpler muscle transfer procedure or a static
sling that restores the ocular or oral continence and balances the face at rest but does
not provide movement.
15.9.1 The Forehead
The forehead undergoes a natural ptosis with age as it loses its natural elasticity.
In paralysis, this is more pronounced and more noticeable when unilateral. In extreme
cases, the brow can obscure vision. There are a number of procedures to correct
forehead ptosis, all of which are static. There is no option for recreating a useful
dynamic brow.
Brow lifts can be performed directly or endoscopically. Endoscopic lifts tend to
produce subtle adjustments as opposed to robust support and therefore produce disappointing
results in facial palsy patients. Direct lifts can be performed to address
either the eyebrow or the whole forehead. An eyebrow lift, or dermodesis, requires
the excision of an ellipse of superciliary skin and frontalis muscle and the pexy of
orbicularis oculi to the periosteum of the forehead (Ueda et al. 1994 ) . The main
risks of this procedure are scarring and damage to the supraorbital nerve which can
give rise to numbness on that side of the forehead.
In an open brow lift the forehead is usually approached via a bi-coronal incision
5 cm posterior to the hairline and the entire brow is elevated to the level of the
supraorbital ridge in the sub-galeal plane. The forehead is re-draped, and the excess
skin posterior is excised in an asymmetric fashion to compensate for the ptosis of
the paralyzed side. The scar is well hidden but can be problematic in male-pattern
baldness and in cases of incisional alopecia. Patients also often complain of parasthesia
posterior to the scar.
15.9.2 The Eyelids
The aim in eyelid surgery is to achieve adequate closure to protect the cornea whilst
minimizing ptosis. This can be achieved through both static and dynamic procedures
tailoring the management to the upper or lower lid depending on the nature of
the de fi cit. The upper eyelid is primarily responsible for eye closure. Gold weights
inserted under the skin of the upper lid to improve lid ptosis were originally described
in the 1960s (Smellie 1966 ) . Gold is an inert metal that triggers little in the way of
an in fl ammatory response. However, there can occasionally be problems with skin
erosion and extrusion of the weight. Test weights can be taped to the outside of the