------------------------------------------------------------------------- TITLE: FACIAL REANIMATION AND REHABILITATION SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: December 19, 1990 RESIDENT PHYSICIAN: F. Brian Gibson, M.D. FACULTY: Chester L. Strunk, M.D. DATABASE ADMINISTRATOR: Melinda McCracken, M.S. ------------------------------------------------------------------------- "This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." I. INTRODUCTION A. Stigmata of Facial Nerve Palsy 1. Cosmetic a. Loss of means of emotional expression, worsened in appearance by mimetic movements of opposite side. b. Cosmetic problem more depressing to older patients. 2. Functional a. Oral incompetence causes drooling and difficulty swallowing as well as problems with speech. b. Lagophthalmos with corneal irritation. B. Intervention by Reconstructive Surgeon 1. Goals a. Corneal protection and amelioration of ptosis. b. Restoration of oral competence and provision for smile c. Normal appearance at rest with hope for symmetry during motion. 2. Limitations a. Spontaneous emotive expression is nearly impossible to achieve b. Voluntary movement can be restored but frequently characterized by synkinesis. c. Facial function is never "normal" 3. Expectations a. Improvement in both function and cosmesis can be expected but multiple procedures may be needed. b. Patient training and effort can improve results. Careful preoperative selection of patients based on realistic expectations of what can be achieved is essential to successful outcome. II. HISTORY 1814 Bell sections facial nerve in monkey, "On cutting the respiratory nerve on the face of a monkey, the very peculiar activity of his features on that side ceased altogether. 1896 Drobnik anastamoses VII and XI to restore facial expression 1903 Koerte does XII to VII crossover. 1911 Lexer and Eden perform masseter muscle transposition 1927 Sterling Bunnell performs first successful facial nerve graft. 1924-32 Ballance grafts intratemporal nerve deficits. 1955-75 Conley popularizes immediate reconstruction and grafting, muscle transfers and nerve crossovers. 1970's Scaramella, Smith and Anderl develop crossface graft. 1978-1990 Microneurovascular free grafts III. MUSCLES OF FACIAL EXPRESSION A. Facial Musculature - 17 paired facial muscles of expression (see table below.) These often interdigitate with one another and insert into dermis and basal epidermis. B. Testing Muscle Function - EMG measures muscle potentials without external stimulation. Normal muscle has no potentials at rest. During maximal contraction muscle fibers fire simultaneously but asynchronously giving "interference pattern". C. EMG Results in Facial Palsy 1. Fibrillation potentials - found in muscles more than two weeks after denervation. 2. Multiple polyphasic potentials - indicate ongoing reinnervation. 3. Low voltage, disorganized potentials - muscle atrophy, lack of motor endplates. IV. PHYSIOLOGIC REPAIR TECHNIQUES A. Primary Repair - produces best results of all reanimation procedures. Need viable ipsilateral facial nerve nucleus, a proximal stump capable of supporting axonal regeneration, distal nerve segments through which axons can grow and viable facial muscles. Grafting is the only way to restore emotional expression but one does not get complete restitution of facial movement. Always some dyskinesis, weakness and mass movement. 1. Timing - should be done at time of injury. Best results obtained within thirty days with gradual drop-off to poor results after 1 year. As long as endoneurial tubes remain intact the graft will have a good chance. 2. Technique - freshen ends under microscope and use 8-0 to 10-0 suture to perform epineural repair. Four quadrant sutures are sufficient, but no tension can be allowed across reanastamosis. Can re-route nerve in mastoid to gain additional length. Fascicular repair or Silastic cuffs probably not necessary. Application of growth factors may be of some benefit. 3. Results - may take 6-24 months to get movement back, often begins as a tingling sensation first felt in the midface. Only 10- 15% get forehead and marg. mandibular function back. B. Interposition Grafting - useful when direct repair would cause tension on suture line. 1. Timing - Best results within 30 days. Usually done at same time as ablative procedure. 2. Techniques - Use greater auricular or sural nerve as graft. Nerve graft is reversed to prevent viable sprouts from exiting at branch sites. Graft must be long enough to be "a gracious plenty" in length. Prefer to reinnervate branches to eyelids and mouth prior to other branches. Almost as good as direct repair in result. C. Facio-facial Crossover - Offers theoretical advantage of bilateral movement driven by same motor nucleus. Done by connecting expendable facial nerve branches on good side to the paralyzed side by a nerve graft. 1. Technical aspects - done via microsurgical approach. Will find some decrease in motor input to non-paralyzed side. 2. Limitations - difficult to get enough "power" to really drive the paralyzed side because only 20-50% of axons grow all the way across face. Also may be difficult to identify branches of VII on bad side. Overall results not as good as other techniques. May be due to prolonged regrowth time. Some have proposed using XII-VII to maintain motor end plates while axons regrow and then "hook-up" the viable axons in a second stage. V. STATIC TECHNIQUES A. Indications - Not as commonly used as before. Considered adjunctive or temporizing measures. Includes fascial slings, dermal slings, alloplastic implants, facelift, browlift, blepharoplasty. B. Usefulness - usually combined with dynamic procedures to give an immediate benefit while reinnervation, etc. proceeds. Especially indicated for patients with a poor prognosis and can be good for older patients in whom minimal surgery is desired. VI. DYNAMIC TECHNIQUES A. Hypoglossal-to-Facial Crossover - relatively simple to perform and should be done at time of resection for malignancy if no other way to repair facial nerve. 1. Indications - when direct repair or grafting unfeasible. May be used in injuries more than one year old as long as distal branches and muscles are viable. 2. Use - elicit facial expression by pressing tongue against incisors. 3. Results - Tone begins to return after 4-6 months. Over next 18 months spontaneous movement gradually returns. 90-95% get good tone at rest with 75-80% with good movement. May have hypertonia because of excessive neural input. Also 50% will have moderate tongue atrophy. 4. Advantages a. Face moves unconsciously during speech, eating or swallowing. b. Direct uncomplicated surgical technique with one scar. c. Greater function because most facial movements are associated with conscious or unconscious movements of tongue. d. No discomfort or significant functional disability. e. Movement around mouth is more normal during speech. B. Phrenic - Facial Crossover - If both XI and XII are gone then can do phrenic crossover. Problems include difficulties learning to move face voluntarily and paralyzed hemidiaphragm. C. XI-VII - either main trunk or selected branches to SCM can be used. If main trunk, have disability and discomfort associated with decreased trapezius function. Also all patients have difficulty learning to use new pathway. All movements are under conscious direction. D. EMG Rehabilitation - uses computerized EMG to monitor and display abnormal muscle activity combined with behavioral modification techniques to help patients modify muscle activity. Essence is progressive shaping of muscle activity by trying to match a desired EMG tracing. Can be used for post-Bell's hyperkinesis or to train people in using a nerve crossover with better results. VII. MUSCLE TRANSFERS A. Indications - include absence of mimetic muscle function, need for additional muscle bulk and myoneurotization, requirement for a complementary procedure during axonal regrowth of crossface graft, etc. Most commonly used are temporalis and masseter. Platysma, SCM and trapezius have all been written about, but have significant disadvantages. B. Temporalis Transfer - can be used to reanimate the oral cavity, midface and eyelids. 1. Advantages - rapid rehabilitation and straightforward technique. 2. Technical points - Approached through incision in temporal area. Take 2-3 cm of pericranium to get adequate length. Also can reverse superficial fascia to add length. Noticeable bulge will be present over zygoma. The arch can be resected giving about 2 cm of length, but this endangers blood supply and removes origin of masseter. The defect in temporal fossa can be improved by filler graft. Make sure strips are sutured to lip medial to nasolabial fold. Must over- correct initially to allow settling. C. Masseter Transposition - indications same as for temporalis transfer. Good for oral reanimation but cannot use for eyelids. Also good to use during primary ablative operation especially in older patients. D. Free Muscle Grafts - idea of denervating muscle for two weeks and then using it to bridge gap from nonparalyzed to paralyzed mimetic muscles was tried with very limited success. E. Nerve-Muscle Pedicle - take small piece of muscle to carry innervation to paralyzed muscle, eg ansa/strap muscle reinnervation of larynx. This proposed by H Tucker but has not really caught on. F. Microneurovascular Muscle Grafts - free grafts from lat. dorsi, gracilis, trapezius and pec. minor have been used with fair results. Facial and sup. temporal used as donor arteries. Can be supplied by crossface (most often), split hypoglossal or ipsilateral nerve graft. Ideal donor muscle should have: reliable neurovascular pedicle, provide excursion equal to normal facial muscles, leave no functional deficit and be located distant enough to allow two teams to operate simultaneously. 1. Two stage procedure - first facio-facial crossover graft placed. Follow Tinell's sign across face for 9-12 months and then place muscle graft. 2. Complications - donor site morbidity is unavoidable. Some risk of graft failure. 3. Results - 80-90% get good symmetry at rest and fairly good active motion. Never completely normal because one muscle applying force along a single vector cannot duplicate function of 10 muscles which normally interact around mouth. 4. Disadvantages - two operative stages, lapse of up to 2 years before regain movement. Complete eyelid closure, forehead movement and oral sphincter tone are never recovered. The face always has some synkinesis and lacks involuntary emotional expression. VIII. EYELID REANIMATION A. Pathophysiology - facial paralysis causes inability to close eyes (lagophthalmos from Gr. lagos for hare, an animal which sleeps with eyes open). Loss of orbicularis tone causes ectropion, disordered lacrimation, corneal irritation, etc. B. Indications for Reanimation - 1. Facial paralysis lasting longer than 6 months without expectation of functional return. 2. Ineffective corneal protection; poor static tone; poor tear function; marked lagophtalmos 3. BAD - ie absence of Bell's phenomenon, anaesthetic cornea and dryness. C. Non-surgical Management - ointments, artificial tears and lid taping at night are useful temporizing measures. D. Tarsorrhaphy - no longer routine because of disadvantages: narrow lid aperture, depression of lateral canthus and difficulty separating lids without residual deformity. E. Lid Shortening - for mild laxity can do simple wedge excision to get horizontal shortening. More moderate cases will need lateral and/or medial canthoplasty. F. Temporalis Transfer - used effectively. Most common complication is ectropion. 1. Technical points - use of epicranial extensions provides a stronger matrix. Ectropion prevented by suturing fascial strips to tarsus and by using anterior portion of muscle without dividing it from main belly. This will allow superior traction to be maintained. 2. Use - eyelid and oral synkinesis. G. Gold Weight - separation of lid and oral function, but does not allow spontaneous blink. Preferred for those who will eventually recover function. May still need to tape at night because of loss of gravity effect. H. Wire Spring - Gold standard, allowing independent oral and eyelid function and restoring normal blink. 1. Cautions - requires considerable experience and expertise to avoid ptosis or incomplete closure caused by either springs that are too open or not open enough. 2. Technique a. use 0.01 orthodontic wire and make spring prior to surgery. Make fulcrum and upper limb flush with periosteum of upper and lateral orbital rims, respectively. b. Lower limb rests against tarsus with tip encased in 2 mm thick dacron patch. Must fashion spring properly to avoid extrusion. Separation of arms of spring should be 1.5 times the interpalpebral distance with eyes open. IX. DECISION-MAKING IN FACIAL REANIMATION A. Cause of Paralysis - traumatic paralysis should be repaired ASAP (less than 30 days). Disruption from tumor surgery should be repaired, or crossover done, at time of surgery. B. Duration - Allow postoperative palsy with intact nerve twelve months to regain function before proceeding with reanimation. If any doubts, explore. No irreversible procedures as long as funciton may return. Nerve grafting or direct repair must be done before one year, XII-VII < 2 years. C. Patient Age - children do not typically have corneal problems while elderly are predisposed to ptosis. D. Patient Prognosis - If patient is sick, want procedures which will give immediate results, e.g. static techniques and gold weight. E. Previous Reanimation Procedures ----------------------------------------------------------------------- BIBLIOGRAPHY 1. Anonsen CK, et al. Facial rehabilitation with the ansa hypoglossi pedicle transfer. OHNS. 1986; 94:302-305. 2. Baker DC. Facial Paralysis. in McCarthy JG (ed). Plastic Surgery. Philadelphia, WB Saunders. 1990. 3. Brudny J et al. Electromyographic rehabilitation of facial function and introduction of a facial paralysis grading scale for hypoglossal-facial nerve anastamosis. Laryngoscope. 1988; 98:405- 410. 4. Freeman MS, et al. Surgical therapy of the eyelid in patients with facial paralysis. Laryngoscope. 1990; 100:1086-1096. 5. MacKinnon SE and Dellon AL. A surgical algorithm for management of facial palsy. Microsurgery. 1988; 9:30-35. 6. May M. The Facial Nerve. New York. Thieme. 1986. 7. May M et al. Bell's palsy: management of sequellae using EMG rehabilitation, botulinum toxin and surgery. Am J Otology. 1989; 10:220-229. 8. Pensek ML et al. Facial reanimation with the VII-XII anastamosis. OHNS. 1986; 94:305-309. 9. Rubin LR. Reanimation of the Paralyzed Face. in Georgiade NG, et al (eds). Essentials of Plastic and Maxillofacial Surgery. Philadelphia. WB Saunders. 1988. 10. Sobol SM and Alward PD. Early gold weight implant for rehabilitation of faulty eyelid closure with facial paralysis. Head and Neck. 1990; 12:149-153. -----------------------------END----------------------------------------