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Facial Reanimation

last modified on: Tue, 04/03/2018 - 13:35

Facial Reanimation

return to: Facial Paralysis (surgery for facial nerve paralysis weakness)

see also: Platinum-Gold eyelid weighting; House-Brackmann Facial Paralysis Scale;  Salivary Gland Surgery Protocols;

    Nerve Grafting for Facial Paralysis (Cross Face Nerve Grafting)

Dr. Douglas Henstrom University of Iowa Facial Plastic and Reconstructive Surgeon, Director of Facial Nerve Center
For appointment please call: 319-356-3600

  1. INITIAL EVALUATION
    1. History and Physical
      1. Establish the etiology: Skull trauma, idiopathic, parotid surgery/tumor, CPA surgery/tumor, penetrating injuries, congenital
      2. Time from injury
      3. Degree of facial dysfunction: House-Brackmann grading system (complete versus incomplete paralysis; total versus segmental paralysis)
      4. General health of patient
      5. Degree of functional problem: exposure keratitis (Ophthalmology Service consult), epiphora, nasal obstruction, poor oral competence, synkinesis, speech difficulties, non-verbal communication
      6. Aesthetic considerations: blepharoptosis, asymmetric smile, synkinesis, brow ptosis
      7. Associated conditions: Hearing loss, balance problems, other cranial neuropathies, cancer, radiation, chemotherapy, prognosis
    2. Electrical Testing
      1. Nerve stimulation test
      2. Electroneurography (most useful for Bell's palsy)
        1. Quantitative measure of degeneration
        2. Obtain periodically from three to 21 days post paralysis
        3. Greater than 90% degeneration implies less than 50% chance of spontaneous recovery
      3. Electromyography
        1. Voluntary and involuntary muscle function
        2. Wait for two to three weeks after injury
        3. Results: Motor unit potentials, fibrillation potentials (severe denervation), polyphasic potentials (early reinnervation) and electrical silence (muscle atrophy, rule out developmental lesion)
    3. Radiography
      1. Temporal bone CT
      2. MRI
    4. Surgical Exploration
      1. Surgical exploration of the facial nerve
        1. Acute, acquired severe degeneration (greater than 90% within two weeks, per ENoG): facial nerve decompression via MCF (Bell's palsy) and/or transmastoid (temporal bone fracture, cholesteatoma, etc)
        2. Developmental paralysis: rule out facial nerve hypoplasia
        3. Penetrating and iatrogenic transection injuries
        4. Contaminated wounds: explore, debride, tag nerve ends, repair within one month to allow for reasonable size match
      2. Muscle biopsy
        1. Longstanding denervation (greater than two years) to determine status of muscle; a lot of variability exists in timing and degree of denervation atrophy
        2. To rule out muscular hypoplasia in developmental paralysis
      3. Nerve biopsy
        1. To establish margins during cancer resection
        2. To determine viability of distal stump to decide between reinnervation procedures versus muscle (or nerve/muscle) transfer
      4. Documentation, photographs and video documentation, FACE quality of life questionnaire.
  2. GENERAL CONCEPTS OF FACIAL REANIMATION
    1. Nerve Injury
      1. Sunderland and Seddon classifications
      2. Wallerian degeneration of the distal nerve occurs when axonal continuity is lost (second-degree, axonotmesis or greater). It takes three days for distal nerve stimulability to be lost.
      3. Regenerative activity is the greatest at 21 days post-injury.
      4. Facial nerve regenerates at approximately 1 mm a day. Distal injuries begin to recover quicker (pes anserinus: six months) and have better prognosis than proximal ones (CPA: 18 months for recovery).
    2. Muscle Denervation
      1. Fiber size decreases to half original size in two weeks.
      2. Muscle atrophy and fibrosis follow long-term denervation, but timing is variable; arbitrary time of 18 to 24 months post injury. "Silence" on EMG or "fibrosis-atrophy" on muscle biopsy will preclude physiologic reanimation of existing facial muscles.
    3. Staging According to Time of Injury and Status of Nerve/Muscle
      1. Stage 1 (0 to 30 days)
        1. Intratemporal injuries
          1. Temporal bone fracture: theoretically, performed at three weeks, when there is the greatest regenerative activity at cell body. In practice, the repair is performed as soon is convenient.
          2. CPA tumor: repair primarily, if possible
        2. Extratemporal injuries: repair ASAP; easier within three days (easier identification of distal stump by electrical stimulation and dissection); best results within one month while there is still reasonable size match.
      2. Stage 2 (one month to one to two years)
        1. Surgical procedures designed to bring neural input back to existing facial muscle.
        2. Absence of proximal nerve stump (use nerve crossover)
      3. Stage 3 (greater than two years)
        1. For a reinnervation procedure to be successful, there must be evidence of viable distal nerve (nerve biopsy) and muscle (fibrillation potentials, of PUPs, on EMG)
        2. "Fibrotic" nerve or muscle requires "nonphysiologic" reanimation (ie, dynamic or static procedures)
  3. OPERATIVE PROCEDURE
    1. Physiologic Reanimation
      1. Neurorrhaphy: surgical suturing/repair of a severed nerve
        1. Use atraumatic, meticulous microsurgical technique and instrumentation.
        2. Avoid tension across suture line; usually, gaps of 1 cm or less can be repaired by mobilization and by primary neurorrhaphy.
        3. Freshen ends by cutting with sharp blade obliquely.
        4. Maintain original relationship of the nerve ends by aligning the mirror images of the fascicles, blood vessels or irregularities on the sides.
        5. Proximal nerve: use perineural technique (remove epineurium if present).
        6. Distal nerve (to pes): use epineural technique; no need to repair most distal branches (eg, medial to lateral orbital rim, medial to nasolabial fold).
        7. Mastoid-meatal rerouting will add approximately 1 cm in length; leave cuff of tissue around mobilized segment; consider risk of devascularization versus use of autograft.
        8. Use fewest sutures possible (9-0 or preferably 10-0 nylon), 1 mm bites, 3-4 simple interrupted, with atraumatic, tapered needle. May consider the placement of tisseel over neurorrhaphy.  
      2. Autogenous nerve grafting
        1. Superior end-to-end repair under tension, despite greater number of anastomoses
        2. Gaps greater than 1 cm need autograft for tensionless sutures
        3. Choice of grafts depends on length, size, availability
          1. Greater auricular nerve (C2 to C3)
            1. Most commonly used
            2. Consent patient for anesthesia of mastoid, auricle
            3. Similar outer diameter to main trunk of FN and has two to three fascicles
            4. Readily available in ipsilateral neck
            5. May provide distal branching as it enters tail of parotid
          2. Sural nerve
            1. When multiple or long (up to 35 cm) grafts are needed
            2. Cross facial nerve grafting
            3. Anesthesia to side and back of distal third of leg, ankle, heel (see Sural nerve harvest protocol) may be contraindicated in patients with diabetes or peripheral vascular disease
          3. Medial antebrachial cutaneous (MAC) nerve
            1. Arm donor site
            2. Little morbidity
            3. Good length and size match
            4. Multiple branches for possible match with distal facial nerve branches
          4. Lateral antebrachial cutaneous (LAC) nerve
            1. Lower arm donor site
            2. Little morbidity
            3. Good length (10 cm) and size match at proximal end, but small distal ends
            4. Multiple branches possible
            5. Easily harvested at time of radial forearm free flap surgery
          5. Preparation of autografts
            1. Handle with care
            2. Should be longer than gap
            3. Preserve in balanced salt solution until ready to use
            4. Reverse direction of the graft to avoid misdirection of axonal regrowth via unused branches
            5. Perineural technique
        4. Nerve crossover anastomosis
          1. When neurorrhaphy and grafting are precluded, such as in cases of absent proximal facial nerve (eg, ablative cancer surgery, temporal bone and CPA tumor resections)
          2. Requires a viable distal nerve and muscle (Stages 1 or 2)
          3. Consent patients for mass movement, muscle atrophy at the distribution of the donor nerve (trade-off), facial twitches, hypertonia of facial muscles, need for rehabilitation/training
          4. Choices
            1. XII to VII: most widely used, best results
              1. Only one suture line or may use jump graft (i.e., sural, greater auricular, etc.)
                1. Branch of CN XII may provide adequate innervation vs. primary nerve trunk  providing excessive innervation.
              2. 95% will achieve good resting tone and eye protection
              3. Discuss tongue atrophy, and need for tongue movement to initiate facial movement
              4. Expect three to six months for facial motion to begin
              5. Perform at the time of tumor resection
            2. Cross-facial nerve (VII to VII)
              1. Needs sural graft of 15 to 18 cm
              2. 50% of fibers, mainly buccal, can be sacrificed without severe facial weakness
              3. Topical lidocaine application, followed by electrical stimulation, helps assessment of the effect of sectioning donor branches on the intact side (use buccal and zygomatic branches)
              4. Better results when used to augment other techniques (XII to VII, gracilis free flap, serratus free flap)
    2. Dynamic Reanimation
      1. Neuromuscular transfer
        1. Used when the extent of nerve or muscle atrophy precludes the use of nerve substitution techniques (Stage 3)
        2. Used to augment unsatisfactory reinnervation procedures
        3. Provides resting symmetry and some voluntary movement
        4. Requires transfer of intact neurovascular supply
        5. Choices
          1. Masseter: for oral commissure and nasolabial fold only (rehabilitation of the lower division); submandibular incision, free anterior two-thirds of the muscle, attach to orbicularis oris through a second skin incision at nasolabial fold, use clear 4-0 prolene sutures, overcorrect slightly; can combine with a static sling
          2. Temporalis: for corner-of-mouth rehabilitation; extended facelift incision for wide exposure, use central one-third of temporalis muscle, mobilize it inferiorly to zygoma, divide and subcutaneously tunnel the flap for individual rehabilitation of nasal ala, corner of mouth, lips
          3. Temporalis Tendon Transfer: for corner-of-mouth rehabilitation; extended facelift incisions for wide exposure, detach coronoid process from mandible and remove tendon from bone, stretch and release muscle inferiorly, suture to modiolus.
          4. Nerve-muscle pedicle: ansa-strap muscle pedicle; Tucker uses it for oral rehabilitation only
    3. Free Muscle Grafts and Flaps
      1. For patients in whom the distal nerve branches have been sacrificed, in whom there is no intact facial musculature, or who have undergone an unsuccessful nerve graft or crossover
      2. Reneurotization from intact homologue muscle will help with symmetric, volitional, and emotional action
      3. Require staged procedure and usually combined with cross-facial grafting
        1. Palmaris longus muscle, for oral sphincter rehabilitation
        2. Extensor digitorum brevis, for eye closure
        3. Gracilis free flap (see protocol)
    4. Static Rehabilitation for Hypokinesis
      1. To achieve symmetry at rest only
      2. To augment dynamic procedures
        1. Targeted face rehabilitation
          1. Fascia lata sling (see Fascia Lata Harvest protocol)
          2. Palmaris tendon suspension
          3. Facelift
        2. Eye rehabilitation
          1. Platinum or gold weight implant, spring implant and suture tarsorrhaphy, to correct lagophthalmos and intractable exposure keratitis. see also: Platinum-Gold eyelid weighting
          2. Bick lateral canthoplasty and lower lid wedge resection, to correct epiphora and conjunctival inflammation
          3. Lateral tarsal strip for lower lid tightening and ectropion
          4. Brow lift, for brow ptosis
          5. Blepharoplasty, for supratarsal fold sagging
        3. Nasal rehabilitation
          1. Alar suspension with fascia lata or septorhinoplasty, for nasal obstruction
        4. Oral rehabilitation
          1. Oral commissuroplasty (Z-plasty) and plication of mouth levators, for drooping mouth
          2. Lower lip lateral wedge resection and digastric transposition, for oral incompetence
    5. Hyperkinesis (Synkinesis) Rehabilitation
      1. Facial Neuromuscular Retraining with facial physical therapy specialist
      2. Botox injection for synkinesis
      3. Selective myectomy: frontalis, mouth levators, mentalis, platysma (see platysmectomy protocol), depressor labii inferioris
      4. Selective neurolysis/neurectomy
      5. Partial lacrimal gland resection, for gustatory lacrimation
      6. Stapes tendolysis, for stapedius synkinesis
  4. SUGGESTED READING
    1. House JW, Brackmann DE. Facial nerve grading system. Otolaryngol Head Neck Surg. 1985;93:146-147.
    2. Maisie Shindo, Facial reanimation with microneurovascular free flaps, Operative Techniques in Otolaryngology-Head and Neck Surgery, Volume 11, Issue 2, Flaps for Head and Neck Reconstruction: Part I, June 2000, Pages 147-149.
    3. P Johnson, A Bajaj-Luthra and R Llull et al., Quantitative facial motion analysis after functional free muscle reanimation procedures, Plast Reconstruct Surg 100 (1997), pp. 1710--1719.
    4. Hadlock TA, Malo JS, Cheney ML, Henstrom DK. Free Gracilis Transfer for smile in Children: The Massachusetts Eye and Ear Infirmary Experience in excursion and quality-of-life changes. Arch of Facial Plast Surg. 2011. May-June;13(3) 190-4.