Facial Nerve Reanimation

MANAGEMENT OF FACIAL NERVE PARALYSIS:
  • Patients with delayed-onset:
  1. Unless medically contraindicated , patients are placed on a 2-week course of systemic corticosteroids and are observed.
  2. Patients with complete paralysis of immediate onset
  3. These patients are tested with the Hilger nerve stimulator between days 3 and 7 after injury.
  4. Immediate onset paralysis due to fracture of mastoid (temporal bone) requires surgery (decompression, re-anastomosis or cable nerve graft).
  5. Treatment of choice for CSOM with vertigo and facial nerve palsy is immediate mastoid exploration
  6. During mastoidectomy or parotidectomy, when the facial nerve is injured, it is immediately explored. Injury to greater than 50% of the neural diameter of the facial nerve is addressed either with primary reanastomosis or reconstructed with the use of a nerve graft. Complete recovery of nerve function is uncommon in these cases.
  7. Facial nerve injuries that occur in an otic capsule–disrupting fracture are explored via a translabyrinthine approach
  • Otic capsule–sparing fractures two surgical approaches
  1. Transmastoid/supralabyrinthine :In patients with well-aerated mastoid air-cell systems or with ossicular discontinuity
  2. Transmastoid/middle cranial fossa : poorly aerated mastoid air cell system or if total facial nerve decompression cannot be achieved via the transmastoid/supra labyrinthine
TREATMENT OF FACIAL NERVE WEAKNESS OR PARALYSIS MAY BE :
  • Supportive
  • Medical
  • Surgical
  • Eye care
  • Combination of all four 
Medical Treatment:
  • Medical treatment is instituted to decrease the swelling.
  • It often involves the use of steroids. This treatment may be continued until the nerve shows sign of recovery.
  1. Prednisolone 60-80 mg/day in divided doses intial 4-5 days,then taper over next 7-10 days.
  2. Antiviral may be effective in some cases of paralysis (bells palsy)(Acyclovir 400mg 5 times a day –10 days Valcyclovir 1000mg /day 5-7 days ).
Eye Care
  • Glasses should be worn whenever the patient outside .
  • Contact lenses should not be worn in this situation . 
  • If the eye is dry, we can use eye drops (artificial tears ) .
  • Ointment may be prescribed for use at bedtime .
  • The best protection for night/sleep hours is to place a clear eye guard over the eye. This can be secured in place with tape.
  • Any eye problems or irritation which does not quickly pass should warrant consultation with ophthalmologist as soon as possible.
  • If facial weakness is anticipated following surgery, a silk thread is sometimes placed in the lid to help close it. When lid closure is adequate this easily removed. In some cases of long-standing paralysis, it may be necessary to insert a weight ( gold plate) into the eyelid to close the eye or perform some other procedure to help the eyelid close (i.e. tarsorrhaphy).
The Nose
  • The collapse of the nasal sidewall can be corrected either from the outside or the inside of the nose.
  • Outside techniques involve placing strips of suspension material from the cheekbone, under the skin, to the nasal sidewall, and suspending the nasal sidewall in its anatomic position. To widen the nasal cavity from the inside, small cartilage grafts can be inserted into the framework of the nose
  1. Adjunctive Procedures:
  2. Soft-tissue procedures to improve symmetry
  3. Rhytidectomy
  4. Excision of redundant intraoral mucosa.
  5. Blepharoplasty
  6. Brow lift
Procedures for drooling
  • Wilkie procedure
  • Submandibular gland resection with parotid duct ligation
  • Modification of normal side to improve symmetry:
  • Neurectomy.
  • Myectomy
Modern studies about facial nerve reanimation
  • The slow rate of facial nerve regeneration following certain injury and even surgical management of paralysed facial nerve can lead to degeneration of the motor end organ and permanent loss of function.
  • A variety of pharmacologic agents have been shown to improve motor nerve regeneration in animals, including ; angiotensin II, nitric oxide,and brain-derived neurotropic factor but due to it is adverse effects and the difficulties with drug delivery and bioavailability,none of these drugs is in clinical use.
  • So this study came to improves recovery of facial nerve after transection and repair depending on daily mechanical whisker stimulation via either protraction or retraction . Full recovery occure 4 months after complete nerve transection .
  • Peripheral Nerve Repair with Cultured Schwann Cells:
  1. The bone marrow is a rich source of mesenchymal cells, which can be differentiated in vitro into Schwann cells and subsequently engrafted into the damaged nerve.
  2. Activated Schwann cells produce collagen and laminin, creating a tunnel of extracellular matrix, and express cell adhesion molecules andreceptors, including IL-1, N-cadherin, gamma integrins, and the neural cell adhesion molecule
  • Other alternative sources of mesenchymal stromal cells are :
  1. Adipose tissue and skin
  2. Also, the bulge area of the hair and whisker follicles
  • Undifferentiated stem cells had a better performance than differentiated (schwann cells) .
  • Effect of Platelet Rich Plasma on Facial Nerve Regeneration
  1. Platelets contain various growth factors such as platelet-derived growth factor (PDGF), transforming growth factor-, and vascular endothelial growth factor.
  2. When platelets are activated,they release these factors, which play important biological roles in various conditions.
  3. It has been demonstrated that neurons express PDGF receptors, PDGF- has been proven to be a survival factor for Schwann cells .
  • Suturing of the nerve and application of PRP demonstrated the greatest increase in the axon counts after treatment than application of PRP without suturing .
COMPICATIONS:
  • Crocodile tears: Occurs due to improper regeneration of facial nerve
  1. There is unilateral lacrimation with mastication
  2. It is due to faulty regeneration of parasympathetic fibres which normally travel through chorda tympani but are misdirected towards greater superficial petrosal nerve and instead of going to salivary glands reach the lacrimal glands. This results in unilateral lacrimation with mastication
  3. Treatment - Sectioning the greater superficial petrosal nerve or tympanic neurectomy
Exam Question
  • Immediate onset paralysis due to fracture of mastoid (temporal bone) requires surgery (decompression, re-anastomosis or cable nerve graft).
  • In Facial nerve is injury during parotid surgery Best management would be immediate repair
  • Treatment of choice for CSOM with vertigo and facial nerve palsy is immediate mastoid exploration
  • Crocodile tears Occurs due to improper regeneration of facial nerve
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