"The human face is the organic seat of beauty. It is the register of value in development, a record of Experience, whose legitimate office is to perfect the life, a legible language to those who will study it, of the majestic mistress, the soul." Farnham, Eliza QUOTE
INTRODUCTION Facial function plays an integral part in our everyday lives Smile; nonverbal communication, etc. Facial paralysis is devastating on many levels Functional Cosmetic Fortunately, a plethora of techniques are available to treat the paralyzed face.
NERVE FIBER COMPONENTS Endoneurium Surrounds each axon Adherent to Schwann cell layer Vital for regeneration Perineurium Encases endoneural tubules Tensile strength Barrier to infection Epineurium (nerve sheath) Outermost layer Houses vasa nervosum for nutrition
NERVE INJURY Two acceptable classification schemes used to describe the histologic changes that occur following nerve injury.
SEDDON CLASSIFICATION (1943) Neurapraxia -a conduction block from transient anoxia owing to acute epineurial / endoneurial vascular interruption resulting from mild nerve manipulation with rapid and complete recovery of sensation. Axonotmesis - This damage extends through and includes the endoneurium with no significant axonal disorganization. Recovery is slow and may take weeks to months, and it may not be complete. Neurotmesis - injuries result from complete or near complete transection of the nerve with epineurial discontinuity and likely neuroma formation. Spontaneous neurosensory recovery is unlikely.
SUNDERLAND CLASSIFICATION (1951)
NEURAL HEALING
FACIAL NERVE
7 th Cranial nerve Nerve of the 2 nd branchial arch Has two roots. A large motor and a smaller mixed sensory and parasympathetic ( nervus intermedius ) FACIAL NERVE
FUNCTIONAL COMPONENTS Brancial motor(special visceral efferent)- Supplies; Stapedius , Stylohyoid, posterior belly of digastric muscle and the muscles of facial expression. Visceral motor(general visceral efferent) Parasympathetic innervations of the lacrimal, submandibular, and sublingual glands, as well as mucous membranes of nasopharynx, hard and soft palate. Special sensory(special afferent)- Taste sensation from the anterior 2/3 of tongue; hard and soft palates. General sensory(general somatic afferent)- General sensation from the skin of the concha of the auricle and from a small area behind the ear.
FUNCTION The facial nerve is responsible for: Contraction of the muscles of the face Production of tears from a gland ( Lacrimal gland) Conveying the sense of taste from the front part of the tongue (via the Chorda tympani nerve) The sense of touch at auricular conchae
LEVEL OF NERVE INJURY AND SYMPTOMS
FACIAL PARALYSIS Commonly Unilateral Nuclear- from destruction of the nucleus Central or cerebral or Supranuclear Peripheral- from a lesion of the nerve
NUCLEAR LESIONS Supranuclear lesions- usually a part of hemiplegia , only the lower part of the face is paralysed. The upper part ( frontalis and part of orbicularis oculi )escapes due to bilateral representation in the cerebral cortex. Infranuclear lesions- entire face is paralysed, as seen in bell’s palsy
ETIOLOGIC CLASSIFICATON OF FACIAL PALSY Various classification have been suggested in this respect. Based on: Course of the nerve Various etiologic causes Degree of dysfunction observed
Vascular abnormalities CNS degenerative diseases Tumours of the intracranial cavity Trauma to the brain Congenital abnormalities and agenesis INTRACRANIAL (CENTRAL) CAUSES
Bacterial and Viral infection Cholesteatoma Trauma- blunt temporal bone trauma, longitudinal and horizontal fractures of the temporal bone and gunshot wounds. Tumours invading the middle ear, mastoid and facial nerve Iatrogenic causes INTRATEMPORAL CAUSES
Malignant tumours of the parotid gland Trauma Iatrogenic causes Primary tumours of the facial nerve Malignant tumours of the ascending ramus of the mandible, pterygoid region and skin. EXTRACRANIAL CAUSES
HOUSE-BRACKMAN(1985) CLASSIFICATION Grade I -normal function without weakness. Grade II -mild dysfunction with sligth facial asymmetry with a minor degree of synkinesis . Grade III -moderate dysfunctions-obvious, but not disfiguring, asymmetry with contracture and/or hemifacial spasm, but residual forehead motion and incomplete eye closure. Grade IV -moderately severe dysfunction- obvious, disfiguring asymmetry with lack of forehead motion and incomplete eye closure. Grade V -severe dysfunction-asymmetry at rest and only slight facial movement. Grade VI -total paralysis-complete absence of tone or motion.
BELL’S PALSY It is defined as an idiopathic paresis or paralysis of the facial nerve of sudden onset. The name was ascribed to SIR CHARLES BELL , who in 1821 demonstrated the separation of motor and sensory innervation of face.
INCIDENCE -15-40 cases per 1 lakh cases SEX PREDILECTION- women more affected than men.3.3 more times common in pregnancy and in the third trimester. AGE - can occur at any age, common in middle aged people. SIDE INVOLVMENT- can be equally seen, usually unilateral.
CLINICAL FEATURES There is sudden onset, usually pt gives h/o occurrence after awakening early morning. Unilateral involvement of entire side of the face. Abrupt loss of muscular on one side of face. Inability to smile, close the eye or raise the eyebrow on affected side. Whistling is not possible.
In an attempt to close eyelid, the eyeball rolls upward. Inability to wrinkle forehead or elevate upper or lower lip. Obliteration of nasolabial fold. Face appears distorted and mask like appearance to the facial features. Speech becomes slurred. Occasionally there is loss or alternative of taste.
Course and prognosis Partial paralysis always resolves completely within a few weeks. Recovery from complete paralysis takes longer (months) and is complete in only about 60-70% of cases. Approximately 15% of patients are left with troublesome residual palsy and or synkinesis .
COMPLICATIONS OF FACIAL PARALYSIS Facial paralysis severely hinders: Normal facial expressions Mastication Speech production Eye protection.
Psychological Trauma The most significant complication is the social isolation these patients often succumb to.
COMPLICATIONS The most serious complication is corneal damage . One of the greatest problems with Bell's palsy is the involvement of the eye if the lid fissure remains open . In this case, eye care focuses on protecting the cornea from dehydration, drying, or abrasions due to insufficient lid closure or tearing
ASSESSMENT AND PLANNING Cause of facial paralysis Functional deficit/extent of paralysis Time course/duration of paralysis Likelihood of recovery Other cranial nerve deficits Patient’s life expectancy Patient’s needs/expectations
EVALUATIONS OF NERVE FUNCTION HISTORY is of vital importance to establish the onset characteristics,duration and degree of recovery. Previous trauma , surgery or infection may help in arriving at a diagnosis Examination of the face at rest and movement. Radiolologic evaluations Nerve excitability tests.
TEAR TEST: ( Schirmer’s test ) Semiquantitative method for comparing lacrimal secretion on normal & affected side. 0.5×5cm strip of filter paper. If moistened length in affected side <25% of normal: significant hyposecretion is present.
TASTE CHORDA TYMPANI : Subjective loss of sensation: unreliable symptom. Swab sides of tongue by a cotton applicator dipped in lemon juice. Threshold measured with electrogustometer (measured electric current). N:30gk microamp Patient percieves this as sour or metallic. SALIVARY FLOW Cannulate wharton duct on each side with no.50 polyethylene tube Stimulate saliva with lemon juice Output of saliva measured in each tube 25% reduction is significant Indicates interruption of chorda tympani or facial nerve to this branch. LIMITATIONS- Unequal penetration of cannula , assymetry of glands.
ELECTRICAL TESTING OF FACIAL NERVE MAXIMUM STIMULATION TEST Pulsed electric current is delivered through a cutaneous electrode Short pulse will stimulate an intact nerve & elicit a muscular twitch. In paralysed facial nerve, this indicates that lesion is neuropraxia & distal neurons have not undergone degeneration Hence differentiates between neuropraxia & axonotmesis : prognostic value.
NERVE EXCITABILITY TEST: Current required for stimulation on normal side is compared with paralysed side. Disadv : even few intact fibres can elicit a response when rest in undergoing degeneration. Muscle twitch response is subjective Uncomfortable procedure Requires patient co-operation ELECTRONEUROGRAPHY Measures compound action potential in facial muscles in response to facial nerve stimulation. Similar to MST, except instead of visually ration the muscle contraction, the muscle action potential is measured on EEG- more accurate. Best test to predict & follow facial nerve recovery. Compare & represent it as percentage of normal side.
Treatment Oral antivirals - Acyclovir Corticosteroids Eye protection Follow progression with serial exams Physiotherapy
MEDICATION If the patient is seen within 2 to 3 weeks of onset of symptoms-tab. Prednisolone in doses of 1mg/kg/d for 10 to 14 days has been recommended with a gradual tapering. Vitamins B1, B6, B12 may be administered. If pt is seen after 3-4 weeks, then steroid therapy is of no use.
A. Acute (< 3 wks) 1. Nerve exploration/decompression 2. Nerve repair a. Primary anastomosis b. Cable grafting i . Great auricular nerve ii. Sural nerve B. Intermediate (3 wks- 2 yrs) 1. Nerve transfer a. Hypoglossal-facial b. Spinal accessory-facial c. Masseteric -facial 2. Cross face nerve grafting using sural nerve C. Chronic (>2 yrs) 1. Muscle transfers a. Temporalis b. Masseter c. Digastrics 2. Free muscle flaps/ microneurovascular transfer a. Gracilis b. Latissimus dorsi c. Serratus anterior d. Pectoralis minor D. Static procedures/ancillary procedures (can be performed at any time period listed above) 1. Gold weight/spring implants 2. Slings 3. Lid procedures Ryan Ridley. Facial Reanimation .Grand Rounds Presentation, UTMB, Dept. of Otolaryngology SURGICAL TREATMENT MODALITIES
Micro-neurological Surgery Facial nerve repair is the most effective procedure to restore facial function in patients who have suffered nerve damage from an accident or during surgery. It involves microscopic repair of a nerve that has been cut.
PRIMARY NERVE REPAIR End-to-end anastomosis preferred No tension Extratemporal repair performed < 72 hrs of injury Most common methods Group fascicular repair Epineural repair Group fascicular repair
Primary Nerve Repair Severed ends of nerve exposed Devitalized tissue/debris removed with fine scalpel Small bites of epineurium Epineural sheath approximated with 9-0 nonabsorbable suture Epineural repair recommended for injury proximal to pes anserinus and intratemporal EPINEURAL REPAIR TECHNIQUE
INTERPOSITION GRAFTING Cable grafts Used when defect > 17mm; nerve cannot be reapproximated without tension Most common Greater Auricular Nerve Sensory nerves from superficial cervical plexus Sural nerve
INTERPOSITION GRAFTING GREATER AURICULAR NERVE Harvesting Located on lateral surface of SCM at the midpoint of a line drawn between mastoid tip and mandibular angle May extend postauricular incision or use separate neck incision Advantages: Proximity to facial nerve Cross-sectional area Limited morbidity Limitations: Reconstruction of long defects Ideal for defects < 6cm in length
SURAL NERVE Anatomy Formed by union of medial sural cutaneous nerve and lateral sural cutaneous branch of peroneal nerve. Advantages : Length : >12cm Accessibility Low morbidity associated with sacrifice Disadv : Variable caliber Often too large Difficult to make graft approximation Unsightly scar
NERVE TRANSPOSITION/ CROSSOVER Nerve transposition is also known as facial-hypoglossal transfer. Restores movement to the side of the face that has been paralyzed. With the stump of the 12th nerve hooked up to the end of the 7th nerve, the face will move when the tongue is moved. 50
CROSSOVER TECHNIQUES INDICATIONS: Irreversible facial nerve injury Intact facial musculature/distal facial nerve Intact proximal donor nerve Prior to distal muscle/facial nerve atrophy Ideal if performed within a year of facial paralysis Adv: Time interval until movement 4-6 months Avoid multiple sites of anastomosis Mimetic-like function achievable with practice Disadv : Donor site morbidity Some degree of synkinesis
Hypoglossal-Facial Technique Parotidectomy incision extended into cervical crease ~ 2-3 cm below inferior border of mandible Facial nerve identified and dissected distal to pes anserinus Identify hypoglossal nerve SCM retracted posteriorly Dissect superiorly until posterior belly of digastic is identified Retract digastric superiorly and CN XII is found inferiorly. Hypoglossal is within 2-3 c m of main trunk of the facial nerve Hypoglossal nerve is dissected anteriorly and medially into the tongue. Transect distal to ansa hypoglossis Facial nerve transected at the stylomastoid foramen Anastomose nerves using 9-0 epineural suture.
Hypoglossal Facial Nerve Transfer Entire hypoglossal nerve transected 40% segment of nerve secured to lower division. 53 Hypoglossal nerve reflected superiorly
Hypoglossal Facial Nerve Transfer Jump graft modification Reflection of the facial nerve out of the mastoid bone. 54
CROSS-FACIAL NERVE GRAFTING Contralateral Facial nerve used to reinnervate paralyzed side using a nerve graft Sural nerve often employed ~25-30cm of graft needed Restitution of smile and eye blinking obtained. Disadvantage 2 nd surgical site Violation of the normal facial nerve
CROSS-FACIAL NERVE GRAFTING FOUR techniques Sural nerve graft routed from buccal branch of normal VII to stump of paralyzed VII Zygomaticus and buccal branch of normal VII used to reinnervate zygomatic and marginal mandibular portions respectively 4 separate grafts from temporal, zygomatic, buccal and marginal mandibular divisions of normal CN VII to corresponding divisions on paralyzed side. Entire lower division of normal side grafted to main trunk on paralyzed side.
MUSCLE TRANSPOSITION (“DYNAMIC SLING”) INDICATION: Congenital facial paralysis Facial nerve interruption of at least 3 years Loss of motor endplates Crossover techniques not possible due to donor nerve sacrifice
TEMPORALIS Often used for reanimation of the oral commisure . Middle 1/3 of muscle is best for transfer (Sherris, 2004)
Temporalis Transfer Incision in preauricular crease extending to superior temporal line Obtain wide exposure of temporalis muscle by dissecting above the SMAS Incise down on periosteum to elevate muscle fibers -Harvest middle 1/3 Large tunnel created over zygomatic arch Orbicularis oris muscle exposed via vermilion border incision at oral commissure Large tunnel over zygomatic arch used to connect oral commisure to zygomatic arch/superior incision. Temporalis flap detached and elevated from its origin and tunneled to the oral commissure . 3-0 prolene used to suture orbicularis to temporalis at oral commissure Overcorrection of nasolabial fold and oral commissure
MASSETER Used when temporalis muscle is not opted. May be preferred due to avoidance of large facial incision Disadvantage: Less available muscle compared to temporalis Vector of pull on oral commisure is more horizontal than superior/oblique like temporalis
Masseter Transfer Expose muscle with gingival incision along mandibular sulcus Dissection carried out in a plane between mucosa and muscle. Muscle freed off of mandible medially and from the inferiolateral edge of mandible. Vertical incision made in inferior portion of muscle Anterior half of muscle is split into 2 divisions. The 2 anterior slips of muscle are tunneled anteriorly to reach the oral commisure via external vermillion border incisions Muscle slips are attached to lips and oral commisure in the deep dermal layer using suture
MICRONEUROVASCULAR TRANSFER FREE MUSCLE FLAPS They have potential of achieving individual segmental contractions Reduction of synkinesis Muscle flaps used are: Gracilis Latissimus dorsi Inferior rectus abdominus
MICRONEUROVASCULAR TRANSFER FREE MUSCLE FLAPS Requires viable muscle and nerve innervation Traditionally done in 2 stages 1 st : Cross-face nerve graft ~ 1 yr prior to muscle transfer 2 nd : Muscle transfer performed after neural ingrowth of graft
GRACILIS “Workhorse” for free muscle transfer Long, thin muscle in medial thigh -Good neurovasular pedicle Adductor artery and vein Anterior obturator nerve 2 stages involved: Sural nerve employed for cross-face graft Gracilis muscle transferred after 6-12 months Vascular anastomosis to the facial artery and vein or to superficial temporal vessels. Obturator nerve of gracilis connected to distal end of sural nerve graft. Anterior Obturator nerve Adductor a. & v.
ADDRESSING PARALYTIC EYELIDS Complications of orbicularis oculi paresis Delayed blinking Impairment of nasolacrimal system Dry eye Risk of exposure keratitis, corneal ulceration and blindness Goal of treatment is to maintain cornea Treatment Options Tarsorrhaphy Gold weight/spring implants Open / endoscopic brow lifts for significant brow ptosis
GOLD WEIGHT IMPLANTATION Small incision made several millimeters above the upper eyelid margin. Tarsal plate exposed with sharp dissection Gold weight secured to tarsus using 8-0 nylon. Wound closed in 2 layers
Horizontal mattress 5-0 nylon Begin 3mm medial to lateral canthus, 6mm from lid margin Stitch travels through gray line to 5mm below lower lid margin Bolster with 3mm, 4-french rubber catheter. Cosmetically unappealing, visual field affected. TARSORRHAPHY
Surgical management of LAGOPHTHALMOS F. Stagno d’Alcontres, G. Cuccia*, F. Lupo, G. Delia, M. Romeo The orbicularis oculi muscle flap: Its use for treatment of lagophthalmos . Journal of Plastic, Reconstructive & Aesthetic Surgery (2010) 63, 416e422
STATIC PROCEDURES Indications: Debilitated individuals; poor prognosis Nerve or muscle not available for dynamic procedures Adjuct procedure with dynamic techniques to provide immediate benefit Advantages: Immediate restoration of facial symmetry at rest No oral commisure ptosis Drooling, disarticulation, mastication difficulties Relief of nasal obstruction caused by alar collapse Static Facial Suspension is used to lift the corner of the mouth so that balance is restored to the face and drooling out of the mouth is helped.
STATIC SLINGS Variety of materials used PTFE ( Gor -Tex) Alloderm Fascia lata Gor -Tex and alloderm have advantage of no donor site morbidity but higher risk of infection.
STATIC FACIAL SLING TECHNIQUE Preauricular , temporal or nasolabial fold incision may be used Additional incisions made adjacent to oral commisure at vermillion border of upper and lower lip Subcutaneous tunnel dissected to connect temporal to oral commisure incisions Dissection may be carried out in midface adjacent to nasal ala, if needed (for alar collapse) Implant strip is split distally to connect to the upper/lower lips Implant secured to orbicularis oris / commisure using permanent suture Implant is suspended and anchored superiorly to superficial layer of deep temporal fascia, or zygomatic arch periosteum , using permanent suture. May also secure to malar eminence using small miniplate or bone anchoring screw
REFERENCES Cranial nerves-Functional Anatomy – Stanley Monkhouse Anatomy for Surgeons: Hollinshead Maxillofacial surgery: Peter Ward Booth Vol 1 & 2 Peterson’s Principles of Oral & Maxillofacial Surgery, 2 nd edition. Oral pathology- Regezi . Textbook of oral surgery – Neelima Malik Gray’s anatomy. Text of Anatomy by Roylce .