page_title: Smile surgery
section_title: Surgical techniques
hierarchical_section_title: Smile surgery / Surgical techniques
caption_attribution_description: English: Algorithm for dynamic smile reconstruction in congenital facial paralysis, the surgical techniques.
context_page_description: Smile surgery or smile reconstruction is a surgical procedure that restores the smile for people with facial nerve paralysis. Facial nerve paralysis is a relatively common condition with a yearly incidence of 0.25% leading to function loss of the mimic muscles. The facial nerve gives off several branches in the face. If one or more facial nerve branches are paralysed, the corresponding mimetic muscles lose their ability to contract. 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. This is because the different branches innervate the frontalis muscle, orbicularis oculi and oris muscles, lip elevators and depressors, and the platysma. The elevators of the upper lip and corner of the mouth are innervated by the zygomatic and buccal branches. When these branches are paralysed, there is an inability to create a symmetric smile.
  Smile surgery is performed as a static or dynamic reconstruction. An example of static reconstruction is upper and lower lip shortening or thickening with commissure preservation.
context_section_description: Selection of the type of nerve transfer is based on the individualised needs and condition of the patient. Individual factors can be patient age, type of paralysis (partial or complete, uni- or bilateral), denervation time of the mimetic muscles, availability of nerve grafts and medical condition of the patient.
  If facial paralysis is caused by trauma or tumour surgery, direct reinnervation of the facial muscles (ideally within 72 hours after facial nerve damage) can be achieved by neurorrhaphy, with or without an interposition nerve graft. (Algorithm 1) Neurorrhaphy is a primary end-to-end reconnection of the facial nerve stumps. However, tension-free reconnection is needed, otherwise scar formation can occur and axons will regenerate outside the facial nerve. If a tension-free reconnection is not possible, interposition nerve grafts are an option. Mostly the great auricular nerve or sural nerve is used as a graft between the two facial nerve stumps.
  In more long standing acquired facial paralysis either a CFNG procedure or "babysitter" procedure are the indicated techniques, with or without a free muscle transfer.(Algorithm 1) Secondary facial paralysis with a denervation time of less than 6 months can be treated with one or more cross facial nerve grafts (CFNGs). During a cross facial nerve graft procedure one or more branches of the non-paralysed facial nerve are divided and connected to one or more sural nerve grafts which are tunnelled to the affected side of the face. Whether these nerve grafts are immediately attached to the paralysed facial nerve branches or after 9 to 12 months depends on the chosen procedure.
  If facial paralysis lasts between 6 months and 2 years, the "babysitter" procedure may be used.(Algorithm 1) During this operation both CFNGs and part of an undamaged donor nerve on the affected side are used. For example, the hypoglossal nerve or masseteric nerve on the affected side can be used as donor nerves. This donor nerve is then attached to the distal end of the paralysed facial nerve. A free muscle transplant is sometimes indicated after the "babysitter" procedure has been performed, depending on the continuity of the injured facial nerve. In other words, if there is contraction of the mimetic muscle during an electromyogram. After a denervation time of approximately more than 2 years, atrophy of the mimetic muscles is permanent. In these cases a free muscle transfer is always performed in combination with a CFNG.
  The procedure of choice for congenital facial paralysis is either CFNG or motor donors, both with a free muscle transfer. (Algorithm 2) Incomplete bilateral Moebius syndrome has the same clinical features as the Moebius syndrome, however some motor function is still apparent on one side of the face. This incomplete syndrome is reanimated with the use of the CFNG and free muscle transfer. The cross facial nerve graft comes from the side with some motor function of the facial nerve. However it first has to be investigated if the motor function of the nerve is strong enough to be separated. A free muscle transfer is always used on the paralysed side, as the muscle is a congenital atrophic muscle. Complete bilateral Moebius syndrome is treated with motor donor nerves on both sides. Optional motor donor nerves are: the masseteric nerve, accessory nerve or hypoglossal nerve. In rare cases when these nerves are also affected, cervical nerve branches can be used. The use of a free muscle transfer is again indicated. The nerve that initially innervated the free muscle transfer is then connected to the provided branches of the motor donor nerve. In Moebius-like syndrome the CFNG is performed, as the facial nerve on the affected side does not have a strong enough motor function. A free muscle transfer is also used, due to the atrophic muscle.
caption: 2. Algorithm for dynamic smile reconstruction in congenital facial paralysis
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