The surgical management of facial nerve injury

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Clin Plastic Surg 30 (2003) 307 – 318
The surgical management of facial nerve injury
Terence M. Myckatyn, MD, Susan E. Mackinnon, MD, FRCS(C)*
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, Suite 17424, East Pavilion,
Box 8238, One Barnes-Jewish Hospital Plaza, Saint Louis, MO 63110, USA
Historical review
Although the concept of repairing injured peripheral nerves is centuries old, it was not until 1821
when Sir Charles Bell demonstrated the loss of facial
expression with transection of the seventh cranial
nerve that surgical restoration of the facial nerve
was attempted [1]. In 1879, Drobnik diverted axons
from an intact spinal accessory nerve to the distal end
of a transected facial nerve, thus affecting the first
nerve transfer to reinnervate the mimetic muscles of
the face [2]. The affects of nerve transfers on the
cerebral cortex were critically reviewed by Kennedy
in 1901 [3], and in 1903, Ballance et al [4] published
a case series documenting their experience with endto-side neurorrhaphy of the transected facial nerve
into an intact spinal accessory nerve and suggested a
hypoglossal-to-facial nerve transfer. Initial attempts
to reinnervate the facial musculature through myoneurotization were met with limited success by Lexer
in 1911 [5], but by 1927, Sterling Bunnell reported
excellent results after primary neurorrhaphy of a
transected facial nerve within the temporal bone [6].
In 1936, the Scottish neurosurgeon Norman Dott used
a sural nerve graft extending from the intracranial to
extratemporal facial nerve to span an intratemporal
defect created by acoustic neuroma resection [7].
Over the past 30 years, the advent and refinement
of microneurosurgical techniques and free tissue
No author has any financial interests associated with any
aspect of this publication.
* Corresponding author.
E-mail address: [email protected]
(S.E. Mackinnon).
transfers has significantly improved treatment options
for extensive or long-standing facial nerve injuries. In
1970, Tamai described free tissue transfer of innervated muscle flaps in canines [8], and, in 1971,
Thompson reported inserting free muscle grafts first
in canines and then in the clinical setting to restore
facial mimetic function [9,10]. The use of the intact
contralateral cervical branch of the facial nerve to
reanimate the territory of the injured ipsilateral facial
nerve was first presented by Scaramella in 1970 and
was later modified to involve sural nerve grafts and
branches of the cervical plexus [11,12]. In 1976, the
microneurovascular transfer of the gracilis muscle to
restore facial animation was described by Harii [13]
and was followed by reports of successful free tissue
transfer and reinnervation of the latissimus dorsi
[14,15] or pectoralis minor [16] to restore facial
animation. To produce a more symmetric and natural-looking result, these techniques have undergone
multiple refinements as more attention is paid to the
fascicular territories within a given muscle [17], the
tonicity of various facial muscles [18], and differences in the distribution of motor endplates on facial
compared with skeletal muscles [19].
Anatomic overview
The complex anatomy of the facial nerve is summarized here and can be thoroughly reviewed in other
texts [20]. The branchial motor fibers constitute the
largest component of the facial nerve and provide
efferent innervation to the stapedius, stylohyoid, posterior belly of digastric, and the muscles of facial
expression. The remaining three components of the
0094-1298/03/$ – see front matter D 2003, Elsevier Science (USA). All rights reserved.
doi:10.1016/S0094-1298(02)00102-5
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facial nerve comprise the nervus intermedius, which
includes visceral motor, general sensory, and special
sensory fibers. A conscious or unconscious impulse is
generated in the neurons of the motor cortex of the
brain and is transmitted via axons traveling via the
corticobulbar tracts and posterior limbs of the internal
capsule toward the seventh cranial nerve nucleus
within the pontine tegmentum. Impulses intended
for transmission to the frontal branch of the facial
nerve project to the seventh cranial nerve nucleus
bilaterally, whereas impulses traveling to the remaining branches of the facial nerve project to the contralateral seventh cranial nerve nucleus. Postsynaptic
branchial motor fibers exit the pons, contribute to the
facial colliculus of the fourth ventricle, and emerge
from the brainstem at the cerebellopontine angle
before entering the internal auditory canal and the
petrous part of the temporal bone.
The intratemporal course of the facial nerve consists of a labyrinthine segment extending approximately 5 mm from the internal auditory canal and
includes the geniculate ganglion. The intratemporal
facial nerve is particularly susceptible to compression
in the relatively narrow labyrinthine segment and to
shearing as it makes a sharp turn, or genu, to enter the
tympanic segment. The tympanic segment extends 8
to 11 mm to a second genu located between the
posterior auditory canal wall and the horizontal
semicircular canal of the middle ear. The nerve
travels vertically another 10 to 14 mm through the
mastoid segment before exiting the stylomastoid
foramen [21 – 24].
The intraneural topography of the intratemporal
facial nerve has been studied extensively. Clinical
reports of consistent deficits of facial animation
associated with nerve injuries at a particular level
after mastoid [25], glomus tumor [26], and decompressive surgeries at the cerebellopontine angle suggested that the intratemporal facial nerve had a
reliable spatial arrangement [27]. These clinical findings were temporarily corroborated in pathophysiologic studies [28] and by May in a feline model [25].
May later noted, however, that the reproducible facial
nerve topography that he had observed histologically
was at least in part due to the presence of a branch of
the trigeminal nerve found in cats but not in humans
and not to a consistent branch of the facial nerve [20].
It is widely accepted that the intratemporal facial
nerve possesses a variable intraneural topography
[29 – 31] and that its spatial relationship to other
intratemporal structures, such as the sigmoid sinus
and carotid artery, are also variable [32].
Several common branching patterns have been
described for the voluntary motor component of the
extratemporal facial nerve [33], with special attention
given to the marginal mandibular [34] and frontal
nerve branches [35 – 38]. Given the variability in
location of the facial nerve branches and the overlap
of facial nerve branches to any given group of facial
muscles [39], careful dissection and a nerve stimulator should be used to confirm the presence of nerve
fascicles and to decide which may be sacrificed in
cross-facial nerve grafting procedures.
The parasympathetic division of the facial nerve is
compromised of visceral motor fibers whose cell
bodies are influenced by the hypothalamus, are
located in the pontine tegmentum, and are collectively
known as the superior salivatory nucleus. These
visceral motor fibers contribute to the nervus intermedius, penetrate the temporal bone, and then divide
into the greater petrosal nerve that innervates the
lacrimal gland and the chorda tympani, which innervates the submandibular and sublingual glands. Cell
bodies for the general sensory component that provides sensation to the conchal skin and the special
sensory component of the facial nerve that travels
along the lingual and chorda tympani nerves and
provides taste to the anterior two thirds of the tongue
reside in the geniculate ganglion. Postsynaptic afferent impulses are transmitted from the petrous temporal
bone through the nervus intermedius and synapse with
the general sensory trigeminal nucleus in the rostral
medulla or with cell bodies modulating taste afferents
within the gustatory nucleus of the pontine tegmentum. These impulses are propagated to thalamic nuclei
before projecting to the sensory cortex.
Surgical management of acute facial
nerve injuries
Primary neurorrhaphy
Acute injuries to the extratemporal facial nerve
should be repaired under magnification and with
adequate lighting and microsurgical equipment
(Fig. 1). A nerve stimulator may be used to confirm
the location of the distal end of the transected facial
nerve for approximately 72 hours after nerve injury
[40]. Beyond this period, the neurotransmitter stores
necessary to depolarize the motor end plates are
depleted and cannot be replenished given the disruption of antegrade axoplasmic transport after
nerve injury [41 – 46]. Thus, early surgery is important and should be done within the 72-hour period
when the appropriate operating room, surgical team,
and equipment are available.
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309
Fig. 1. Algorithm for the management of facial nerve injuries. When possible, primary neurorrhaphy of a facial nerve injury is
performed within 72 hours to enable identification of the distal end with a nerve stimulator during exploration. Procedures
involving cross-facial nerve grafts (CFNG) or free tissue transfers are performed exclusively on individuals who are capable of
enduring a prolonged general anesthetic and who are sufficiently motivated to remain compliant with the subsequent
rehabilitation. * Partial CN XII to CN VII transfer.
Ipsilateral nerve grafts are indicated in the reconstruction of segmental defects of the facial nerve
when both ends of the transected nerve can be
reliably identified and when it is not possible to do
a primary repair (Fig. 1). In preparation for nerve
grafting, neurolysis and dissection of the transected
facial nerve stump to the level of clearly defined
healthy fascicles proximally and equally judicious
dissection of the distal facial nerve stump out of the
zone of injury must occur. Once the facial nerve
stumps are ready for grafting, the sural nerve, the
greater auricular nerve, and the medial antebrachial
cutaneous nerves are most commonly used. Our
preference is to use medial or lateral antebrachial
cutaneous nerve grafts.
Although surgical technique is an important consideration in performing primary neurorrhaphy or
nerve grafting of the facial nerve, it is its variable
spatial arrangement that most significantly affects the
success of the repair [20,25,28]. Although the senior
author has acutely repaired transected buccal and
zygomatic branches of the facial nerve medial to a
perceived line drawn from the lateral corner of the eye
to the lateral corner of the lip with excellent success,
injuries in this region are commonly observed, and
facial mimetic function tends to recover. As the facial
nerve ramifies in its peripheral extent, its topography
becomes less complex, and subsequent repairs are
more successful, although even its distal branches
may not be committed to a single muscle group
[39]. Also, unlike skeletal muscle (which possesses
a single, centrically located motor end plate innervated by a single motor nerve), individual facial
muscle fibers can possess multiple eccentrically
located motor end plates innervated by multiple facial
nerve branches [19,47]. The various facial muscles
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also possess a diverse range of fiber compositions and
diameters: Some (eg, the procerus) are phasic and
respond rapidly when stimulated, whereas others (eg,
the buccinator) are slow twitch and contribute more to
underlying facial tone [18,48].
Given the complex patterns of innervation of the
facial musculature and the inconsistent spatial orientation of the facial nerve, reinnervation after nerve
repair is frequently accompanied by some degree of
synkinesis or dyskinesis. Synkinesis is defined as the
abnormal, simultaneous contraction of a group of
muscles with voluntary or involuntary facial expression. Dyskinesis occurs when the facial muscles
contract in an unintended fashion with facial expression. Synkinesis is the result of the successful innervation of unintended targets in addition to the intended
targets, whereas dyskinesis suggests that some of the
intended targets were not appropriately innervated.
Some investigators have suggested that in addition to
aberrant neural regeneration, synkinesis may be
related to hyper-excitability of the facial nerve nucleus
after injury to the facial nerve [49,50]. Synkinesis or
dyskinesis becomes more common as the site of facial
nerve injury becomes more proximal from the stylomastoid foramen and into the temporal bone.
Cross-facial nerve graft
The cross-face nerve graft, as described by Anderl
[51,52] and Scaramella [11,53], can be used when the
proximal stump of the injured facial nerve is unavailable (Fig. 1). By diverting extratemporal axons from
the contralateral facial nerve whose cortical origins
match those of the injured side, the problems of
synkinesis and involuntary muscular contractions
can be avoided. Exposure is gained via a preauricular
incision that is carried posterior to the auricle and
then caudal to the mandibular angle. Branches of the
contralateral facial nerve are exposed and identified
with a nerve stimulator. Typically, one or two nerve
branches causing elevation of the corner of the
mouth, upper lip, and ala are taken for nerve grafting.
Branches that preserve eyelid function, including a
prominent branch motorizing upper and lower lids
and branches to the zygomaticus major and other
perioral musculature, are protected to preserve the
function of the nonparalyzed side. The sural nerve is
used as the donor nerve graft because of its length,
caliber, and relative expendability. Neurorrhaphy is
performed between sural nerve graft and the transected donor facial nerves on the nonparalyzed side.
The grafts are first tunneled subcutaneously across
the upper lip and delivered to the contralateral side.
The distal end of the graft is banked subcutaneously
in the preauricular area until free tissue transfer is
undertaken. If cross-facial nerve grafting is performed
shortly after the period of denervation, however,
neurorrhaphy to the contralateral facial nerve can be
considered. Using this model, the senior author has
shown that, in instances where distal neurorrhaphy
was completed at the time of the initial procedure,
nerve fiber diameter, myelin thickness, and the density of neural tissue was greater than when the distal
end was banked in the preauricular position [54].
When it is meticulously performed in patients with
salvageable facial muscles who are capable of enduring a prolonged anesthetic and when there is sufficient donor nerve material, the cross-facial nerve
graft with a distal repair is our preferred technique in
restoring facial nerve function when the proximal
stump is unavailable for ipsilateral grafting.
Nerve transfers
Defects of the facial nerve that are not amenable
to primary repair, an ipsilateral nerve graft, or a crossfacial nerve graft can be reconstructed with a nerve
transfer procedure. Axons from the transferred donor
nerve may be delivered to the distal end of the
transected facial nerve using direct neurorrhaphy or
an interposition nerve graft to enable tension-free
repair. Unfortunately, control of the facial mimetic
musculature on the paralyzed side of the face relies
upon activation of the donor nerve’s intended target.
Patients treated with a hypoglossal-facial nerve transfer need to manipulate their tongues to contract their
neurotized facial musculature and may develop dyskinetic facial movements with speech, chewing, and
other tongue movements and hemiatrophy of the
tongue on the paralyzed side. Like the hypoglossalfacial nerve transfer, other nerves transferred to the
distal end of the transected facial nerve, including the
trigeminal [55,56] and spinal accessory nerve, result
in gross [4,57,58], unintended contractions of the
facial musculature. Over time, however, a number
of patients demonstrate some degree of motor
re-education whereby similarly innervated facial
muscles display the ability to contract independently
after nerve [59] or muscle transfer procedures [60].
Some authors have suggested that this process of
motor re-education is related to neuronal sprouting in
the region of the pontine nuclei [60]. Others have
suggested that instead of restoring facial nerve function, dormant branches of the trigeminal nerve may
motorize denervated facial muscles, as suggested by
rare instances of restoration of facial animation with
no surgical intervention [61].
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Surgical technique: partial hypoglossal-to-facial
nerve transfer
To minimize the deficits caused when the ipsilateral hypoglossal nerve is sacrificed to enable an
end-to-end hypoglossal to facial nerve transfer, endto-side hypoglossal-to-facial nerve transfers have
been described clinically [62 – 65], and a partial hypoglossal-to-facial nerve transfer is our preferred technique. Specifically, the ipsilateral hypoglossal nerve is
identified proximally, where it is known to have a
monofascicular pattern, and is followed distally where
a polyfascicular pattern has been demonstrated in
cadaveric dissections [66]. A nerve stimulator is then
used to identify fascicles of the hypoglossal nerve
innervating the posterior aspect of the tongue. These
fascicles are carefully protected when a neurectomy
involving 25% of the remaining hypoglossal nerve is
performed and the transected distal end of the facial
nerve is coapted end-to-side to the neurectomized
hypoglossal nerve. End-to-side neurorrhaphy of the
facial nerve to the hypoglossal nerve, usually with an
interposition nerve graft obtained from the medial
antebrachial cutaneous nerve, is associated with
adequate reinnervation of facial nerve targets and
usually without appreciable loss of tongue motion,
ipsilateral bulk, or significant speech deficits.
Nerve transfers can be used as a definitive procedure to reanimate the paralyzed face but may also
be used to provide trophic support to the denervated
neuromuscular junction if a cross-facial nerve graft
and subsequent prolonged period of denervation is
expected [67 – 70]. The hypoglossal and accessory
nerves have been used to temporarily maintain the
neuromuscular junction of denervated facial mimetic
muscles [57]. Recent animal studies, however, challenge the utility of such a ‘‘baby-sitter’’ procedure,
suggesting that repeated episodes of denervation
followed by reinnervation leads to less muscle recovery than a single prolonged period of denervation
followed by a single reinnervation [71].
Surgical management of established facial palsy
Regional muscle transfers
It is well known that periods of denervation in
excess of 1 year in the extremities and 1 to 2 years in
the face leads to the irreversible loss of functional
motor end plates and muscle contraction in response to
neural stimuli. As a result, reinnervation alone does not
successfully restore muscle contraction. As shown in
Fig. 1, regional muscle transfers using the temporalis
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or masseter [72], cross-facial nerve grafts combined
with free tissue transfers in a one- or two-stage
procedure, and various ancillary static procedures
can be used when the motor end plates of the facial
muscles are not salvageable. Regional muscle transfers
are preferred in patients who do not desire a two-stage
operation or are not medically suitable for a prolonged
anesthetic or free tissue transfer. Some groups favor
using a portion of or the entire masseter muscle alone
or in combination with a temporalis muscle transfer for
facial reanimation, particularly when the natural vector
of the patient’s smile is in a more lateral direction
[73,74]. We most frequently use a partial temporalis
muscle transfer. The vector-of-pull for this transfer
extends from the modiolus to the anterior zygomatic
arch and resembles the vector created by contraction of
the zygomaticus major muscle.
Surgical technique: partial temporalis transfer
Exposure for the temporalis muscle transfer
begins with an incision extending from the preauricular skin cephalad over the temporalis musculature
(Fig. 2). A skin flap is raised just superficial to the
parotid fascia and is extended medially toward the
nasolabial fold and above and below the oral commissure. If the patient has partial facial nerve palsy,
care is taken to identify and preserve branches of the
facial nerve that may be stimulated intraoperatively.
Superiorly, the dissection continues to the deep fascia
of the temporalis muscle. A superiorly based flap of
deep temporal fascia, approximately 4 cm wide, is
fashioned. The cephalic attachment of this fascia to
the temporalis muscle is reinforced with nonabsorbable suture. This superiorly based fascial flap extends
the reach of the muscle transfer and functions as a
tendon that can be secured to the modiolus and
orbicularis oris. After the fascial flap is mobilized,
the middle third of the temporalis muscle is elevated
from cephalad to caudad and is proximally based.
Although care must be taken in elevating a portion of
the temporalis muscle for transfer, a recent cadaveric
study has confirmed that the temporalis is consistently well vascularized by three distinct arteries and
in a majority of cases is simultaneously innervated by
buccal, mandibular, and masseteric branches of the
trigeminal nerve [75]. With the temporalis elevated to
the superior border of the zygomatic arch proximally,
the flap is transposed to the modiolus, where the flap
is secured to match the vector of smile noted on the
contralateral side. The repair of the transferred muscle
flap around the corner of the mouth is the same as for
insetting a free muscle transfer. Nonabsorbable clear
sutures are placed in the orbicularis oris muscle above
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Fig. 2. Middle-aged woman with established facial palsy on the right side. (A) Preoperative photo while smiling.
(B) Intraoperative photo demonstrating temporalis muscle transfer. (C) Two-year follow-up while smiling.
T.M. Myckatyn, S.E. Mackinnon / Clin Plastic Surg 30 (2003) 307–318
(three sutures), below (one or two sutures), and at the
modiolus (one suture). At the time of the flap inset, it
is important to overcorrect the vector by pulling up
the upper lip and corner of the mouth to produce
some incisor show. An intra-oral splint is placed to
support the oral commissure on the affected side and
is maintained for 6 weeks postoperatively.
In the senior author’s experience, the temporalis
muscle transfer is a reliable alternative to microsurgical techniques in restoring facial mimetic function
after prolonged denervation. In addition, some animal
data suggest that muscle transfers may stimulate
neurotization of the facial musculature [76]. In a
recent animal study, the retrograde tracer horseradish
peroxidase was identified in the trigeminal nucleus of
guinea pigs after injection of the facial nerve-innervated zygomaticus major muscle. Although the possibility of duel innervation of the facial mimetics by
the trigeminal and facial nerve has been mentioned
previously [61], these investigators suggested that
their results may have been due to a phenomenon
whereby temporalis muscle transfers may stimulate
neurotization of the facial mimetic muscles [76].
Clinically, however, the degree of success achieved
with temporalis muscle transfers depends upon the
patient’s ability to independently contract the temporalis on the affected side to match the degree of facial
muscle contraction on the normal side. Although
involuntary facial contractions are rarely symmetric,
in our experience patients do extremely well with
motor re-education after these muscle transfers.
Free tissue transfers
To avoid synkinesis and asymmetric, unintended
facial expressions in the individual with long-standing facial nerve injury, vascularized free tissue transfers motorized by an ipsilateral nerve, cross-facial
nerve graft, or a long neural pedicle extending to a
branch of the intact contralateral facial nerve may be
used. Described free tissue transfers for facial reanimation include the gracilis [13], latissimus dorsi
[14], pectoralis minor [16], and rectus abdominis
[77]. Our current practice is to perform a vascularized, free tissue transfer of the gracilis muscle
approximately 8 months after cross-facial nerve grafting (Fig. 3). The gracilis muscle remains our muscle
of choice based on ease of harvest, its parallel fiber
orientation, and a reasonable length of excursion with
contraction. Preparation of the recipient site involves
a meticulous dissection superficial to the parotid
fascia and superficial myoaponeurotic system that
avoids the cross-facial nerve graft. Manktelow and
Zuker have recently reported a variation on their
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original cross-facial nerve graft technique, referred
to as the ‘‘short-cross facial nerve graft’’ [78]. Instead
of performing the neurorrhaphy in the preauricular
area as occurred when a 20-cm long sural nerve graft
was used, a graft measuring 7 to 8 cm is used and
resides superior to the incisors in the upper buccal
sulcus after the first stage of cross-facial nerve grafting. The anterior branch of the obturator nerve that
innervates the gracilis extends approximately 6 cm so
that the neurorrhaphy is performed within the dissected buccal mucosa.
One-stage free tissue transfers
Over the last decade, there have been a number of
reports advocating one-stage free muscle transfers to
reanimate the paralyzed face. The success of onestage free tissue transfer of the abductor hallucis
longus to restore facial animation in three patients
was first reported in 1992 [79] and was later updated
[80]. Koshima et al then described an innervated
rectus femoris flap for facial reanimation [81]. Nerve
grafting could be avoided secondary to the length of
the femoral nerve pedicle—often reaching 20 cm—
that could easily extend from the muscle flap to an
intact buccal branch of the contralateral facial nerve.
This group subsequently described a doubly innervated rectus femoris flap whereby lip elevation was
provided via the long femoral nerve segment coapted
to the contralateral facial nerve. The inferior segment
of the rectus femoris muscle responsible for lip
depression possessed a shorter motor nerve that was
coapted to the ipsilateral masseteric nerve [82].
One-stage free tissue transfers possessing a long
motor nerve that can be coapted to the contralateral
side have also been described for the gracilis [83,84],
latissimus dorsi, [85], and the internal oblique musculature [86]. Although advocates of a two-stage
approach to facial reanimation with free tissue transfers do so primarily to minimize the period of
muscular denervation, none of these groups performing one-stage operations report problems with muscle
reinnervation clinically or with EMG confirmation
[83]. Muscular recovery as early as 6 months after
one-stage procedures has been reported, and one-stage
procedures are used successfully to treat children
with Moebius syndrome [87]. Harii gives two explanations for the paradoxic acceleration in muscle
reinnervation that he has observed after one-stage
transfers [85]. First, retrograde blood flows from the
muscle and into its long vascular pedicle, converting
it into a vascularized nerve graft. Second, a sural
nerve graft possesses two suture lines, versus the
single neurorrhaphy required for a one-stage transfer.
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Perhaps the additional scar and technical considerations of a second neurorrhaphy limits the efficacy of a
nerve graft versus the one-stage technique. One
concern that we have had with the one-stage free
tissue transfer technique relates to the frequent
requirement of an additional anterior facial incision
to gain exposure for the extended neural pedicle as it
passes to the nonparalyzed side of the face [13,86].
Perhaps the buccal sulcus incision described by
Manktelow and Zuker for two-stage, free tissue
transfers [78] could be used to help pass the nerve
graft to the contralateral side and could be combined
with a contralateral facelift incision instead of a more
anterior incision to gain exposure of the contralateral
normal facial nerve. Although long-term follow-up
and further study of the integrity of the neuromuscular junction in one-stage transfers is warranted, this
technique is gaining favor for its shorter recovery
period and reduced operative times.
Gold weight for lagophthalmos
Injuries to the facial nerve, most particularly the
zygomatic branch, interfere with lid closure because
the levator palpebrae superioris and Mueller’s
muscles elevate the upper lid unopposed. Exposure
keratitis and tearing are common sequelae. Although
static procedures involving magnetized rods [88] and
dynamic procedures using palpebral springs [89] and
slips of a regional temporalis muscle transfer have
been described [90], we frequently use a gold weight
to achieve eyelid closure [91,92]. This technique has
been a reliable method for treating lagophthalmos in a
number of series [93] and relies on the weight of the
implant and gravity to produce eye closure with the
patient in the upright or reclined position. Preoperatively, trial weights ranging from 0.8 to 1.6 g are
placed on the upper lid to determine the lightest
weight consistently capable of producing eye closure.
Intraoperatively, the appropriately sized 24-carat gold
weight, which usually weighs 1 g, is placed immediately superficial to the tarsal plate and centered over
the pupils with the patient in centric gaze. To avoid
implant visibility, the weight is placed sufficiently
cephalad that the resultant bulge is not visible with
the eyes open. In a retrospective review, Pickford et al
[94] noted that although patient satisfaction was
generally high, selection of an excessively large
weight was the most common factor contributing to
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morbidity. Implant visibility, extrusion, downward
migration, and ocular irritation are sequela noted by
us and others [95]. Fortunately, the gold weight can
be downsized and repositioned as needed because
this technique permits subsequent adjustments with
little morbidity.
Other ancillary procedures
Reconstruction after facial nerve injury is not
confined to a single or staged procedure but may
require several ancillary procedures. Procedures that
may improve facial aesthetics after facial nerve injury
include debulking procedures (particularly when
regional or free flaps are used), tightening or repositioning procedures, or selective denervations to
restore symmetry. Static facial reconstructions with
fascia lata or Gore-Tex [96] and common facial
cosmetic procedures (eg, brow lift for eyebrow ptosis
and rhytidectomy) are also implemented. Denervation
of the perioral musculature may cause significant lip
asymmetry, which can be restored with autologous
reconstructions involving pure fat grafts [97], dermal
fat grafts [98], and fascia lata grafts [99]; autologous
forms of injectable collagen; or other alloplastic
alternatives [100]. Occasionally, facial symmetry is
best restored by limiting the function of the nonparalyzed side. When overpull by muscles such as
the frontalis or depressor anguli oris distorts facial
harmony, for example, botulinum toxin can be used
judiciously to temporarily denervate them [101,102].
Typically, any touch-up procedures are performed 18
to 24 months after the last reconstructive procedure to
provide sufficient time for wound healing and scar
formation and to allow the patient to identify which
aspects of their facial aesthetics and function they
wish to change.
Summary
Treatment of facial nerve injuries depends upon a
detailed understanding of its anatomic course, accurate clinical examination, and timely and appropriate
diagnostic studies. Reconstruction depends upon the
extent of injury, the availability of the proximal stump,
and the time since injury and duration of muscle
denervation. Although no alternative is perfect, these
techniques, in combination with static and ancillary
Fig. 3. Boy with established facial palsy on the right side. (A) Preoperative photo while smiling. (B) Intra-operative photo
demonstrating free tissue transfer of gracilis muscle 8 months after receiving cross facial nerve graft. (C) Two-year follow-up
while smiling. (D) Seven-year follow-up while smiling.
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procedures, can protect the eye, prevent drooling,
restore the smile, and improve facial symmetry. New
techniques (including single-stage free tissue transfers
and bioengineered nerve grafts), further research on
the characteristics of the facial musculature, and
methods of preserving the neuromuscular junction
will undoubtedly manifest themselves as further
refinements of established surgical techniques.
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