Facial nerve paralysis is a relatively common condition with a yearly incidence of 0.25% leading to function loss of the mimic muscles.

[2] This may lead to several symptoms such as incomplete eye closure with or without exposure keratitis, oral incompetence, poor articulation, dental caries, drooling, and a low self-esteem.

An example of static reconstruction is upper and lower lip shortening or thickening with commissure preservation.

Eight years later, Terzis introduced the "babysitter" procedure, which consists of a combination of CFNGs and a simultaneous partial hypoglossal to facial nerve transfer.

[2] The main indications for dynamic smile reconstruction are unilateral or bilateral facial paralysis due to acquired and congenital causes.

[2] Trauma, Bell's palsy and tumour extirpation are examples of secondary or acquired facial paralysis.

Moebius syndrome is a congenital neurological disorder with bilateral paralysis of both the facial and abducens nerves.

[8] However, tension-free reconnection is needed, otherwise scar formation can occur and axons will regenerate outside the facial nerve.

[5] A free muscle transplant is sometimes indicated after the "babysitter" procedure has been performed, depending on the continuity of the injured facial nerve.

[2] The procedure of choice for congenital facial paralysis is either CFNG or motor donors, both with a free muscle transfer.

In Moebius-like syndrome the CFNG is performed, as the facial nerve on the affected side does not have a strong enough motor function.

Advantages of this muscle are its relatively small size and flat and fan-like shape, obviating the need for trimming without bulkiness as a result.

[12] However, as dissection of this muscle is rather difficult and the neurovascular anatomy is variable, nowadays surgeons tend to use it less frequently.

[7] During a one-stage or two-stage CFNG procedure, one or more non-affected facial nerve branches are used for reinnervation of the paralysed side.

Upon electrical stimulation, the nerve which produces the best contraction of the zygomatic muscles (and so the appearance of a smile) is selected.

[citation needed] Likewise the "babysitter" procedure uses the CFNG, in combination with the masseteric or hypoglossal nerve.

These hypoglossal- or masseteric-facial nerve anastomosis using a 'jump' interposition graft can be used to directly reinnervate the paralysed facial muscles or as a "babysitter" procedure.

If a two-stage procedure is performed, the CFNGs are connected to the distal branches of the paralysed facial nerve during the second stage 9 to 12 months later.

Primary neurorrhaphy provides the best possible outcome, as the anatomy and function of the damaged facial nerve is restored.

[9] The contraction amplitude after using a CFNG is usually not very powerful, but it results in a relatively spontaneous smile because the contralateral healthy facial nucleus controls the movements.

[15] The use of the masseteric nerve provides an amount of movement that is within the normal range, resulting in a more symmetrical but not completely emotional smile.

[4][5] However, after the use of the hypoglossal nerve control of facial movements is hard to obtain by the patient and a spontaneous smile may not occur at all.

[14] The primary neurorrhaphy and free muscle transfer are the only options to restore a true spontaneous smile.

[7][13] Although the masseteric nerve transfer provides a strong smile within the range of normal, it never becomes truly spontaneous and emotional.

[14] But with practice, the majority of patients can provide a spontaneous smile some of the time[14] due to the plasticity of the cerebral cortex.

[8] With the use of the CFNG there is a risk of sensory deficits in the lower part of the leg, due to the sural or sapheneous nerve graft.