Facial nerve and its disorder UG MBBS.pptx

prepared this presentation for undergraduate MBBS students. Please go through this and provide your valueable suggestions to improve . Thank You Dr Diwash Sunar MBBS, MS - ENT (AIIMS, New Delhi) Lecturer - Birat Medical College Teaching Hospital [email protected]

1. Anatomy of Facial Nerve and it’s Disorders Dr. Diwash Sunar MBBS (Manipal, KU) MS – ENT Head & Neck Surgery ( AIIMS, New Delhi ) Lecturer – BMCTH, KU

2. Learning Objectives Anatomy of Facial nerve Course and branches of Facial Nerve Functions of Facial nerve Disorders associated with facial nerve Clinical examination of facial nerve

3. Pre – Test ?? Only for ENTertainmENT Answer of Knowledge or Game of guess

4. Smallest segment of facial nerve is : Intracanalicular Labyrinthine Tympanic Mastoid

5. 2. Facial paralysis during pregnancy is associated with - Hydramnios 1 st trimester Pre-eclampsia Anemia of pregnancy

6. 3. Melkersson -Rosenthal syndrome includes all except : Facial paralysis Fissured tongue Circumoral oedema sarcoidosis

7. 4. All muscles are supplied by facial nerve except : Occipitofrontalis Anterior belly of digastric Risorius procerus

8. 5. Hyperacusis in bell’s palsy is due to the paralysis of which muscle? Tensor tympani Levator veli palatini Tensor veli palatini stapedius

9. 6. Recurrent facial paralysis is seen in all except – Acoustic neuroma Diabetes Sarcoidosis cholesteatoma

10. 7. Iatrogenic traumatic facial nerve palsy is most commonly caused during : Myringoplasty Stapedectomy Mastoidectomy ossiculoplasty

11. 8. In ramsay hunt syndrome, Herpes zoster involves which of the following ganglia? Scarpa ganglia Spiral ganglia Geniculate ganglia Stellate ganglia

12. Facial Nerve

13. Facial Nerve 7th cranial nerve Mixed nerve with motor and sensory roots FN nucleus is situated in the lower third of Pons beneath the 4 th ventricle Fibres passes around the abducent nucleus before emerging from the brainstem Emerges from the brain stem between the pons and medulla, controls muscles of facial expression, and muscles of the scalp and ear, as well as the buccinator, platysma, stapedius, stylohyoid, and posterior belly of the digastric. Functions in conveyance of taste sensations from the anterior two thirds of the tongue

14. Carries parasympathetic secretory fibres to  submandibular and sublingual salivary glands, lacrimal glands, and mucous membranes of oral and nasal cavities. Conveys exteroceptive sensation from the eardrum and external auditory canal, proprioceptive sensation from muscles it supplies, and general visceral sensation from salivary glands and mucosa of the nose and pharynx.

15. Facial nerve is formed mainly of two parts: 1. Facial nerve proper (motor) – Nerve of wrisberg 2. Nervus intermedius ( Somato -s ensory)

16. Arises from facial motor nucleus in pons Supranuclear innervation to the muscles of facial expression arises from the lower third of contralateral precentral gyrus in facial area of motor homunculus. Portion of nucleus that innervates the lower half of the face has predominantly contralateral supranuclear control;  Portion that innervates upper half of face has bilateral control. 1. Facial nerve proper (motor)

17. 2. Nervus intermedius Sensory and autonomic component of the facial nerve Runs in a position intermediate between CNs VII and VIII across the CPA At first external genu, Nervus Intermedius fuses with the geniculate ganglion.

18. Facial Nerve Functional components [SVE] [GVE] [SVA] [GSA]

19. Course of Facial Nerve: Intracranial course Extracranial course Intra-Temporal course Extra-temporal course

20. Intracranial course From brainstem to fundus of IAC Covered only by a thin layer of glia 15-18mm

21. Extra-cranial Intratemporal course within Fallopian canal From IAC to stylomastoid foramen Lenghth of this course = 28-30mm Divided into 4 parts : Meatal Labyrinthine Tympanic mastoid

22. Meatal segment (8 mm) - Within internal acoustic meatus 2. Labyrinthine segment (4 mm) shortest segment of FN From fundus of IAM to the geniculate ganglion where nerve takes a turn posteriorly forming a "genu" narrowest diameter (0.61-0.68 mm) oedema or inflammation can easily compress the nerve and cause paralysis. 3.  T ympanic or horizontal segment (11 mm) From geniculate ganglion to just above the pyramidal eminence. It lies above the oval window and below the lateral semicircular canal. 4. Mastoid or vertical segment (13 mm) From the pyramid to stylomastoid foramen. Between the tympanic and mastoid segments is the second genu of the nerve.

23. EXTRACRANIAL EXTRATEMPORAL COURSE From stylomastoid foramen to the termination of its peripheral branches

24. BRANCHES OF FACIAL NERVE  1. GREATER SUPERFICIAL PETROSAL NERVE (GSPN) arises from geniculate ganglion and carries secretomotor fibres to lacrimal gland and the glands of nasal mucosa and palate.

25.  2. NERVE TO STAPEDIUS It arises at the level of second genu and supplies the stapedius muscle.

26. 3. CHORDA TYMPANI It arises from the middle of vertical segment, passes between the incus and neck of malleus, and leaves the tympanic cavity through petrotympanic fissure. It carries secretomotor fibres to submandibular and sublingual glands and brings taste from anterior two-thirds of tongue.

27. 4. POSTERIOR AURICULAR NERVE It supplies muscles of pinna, occipital belly of occipitofrontalis and communicates with auricular branch of vagus . 5. MUSCULAR BRANCHES Nerve to stylohyoid and posterior belly of digastric.

28. 6. Peripheral Branches (Terminal Branches) The nerve trunk, after crossing the styloid process, forms two divisions, an upper temporofacial and a lower cervicofacial, which further divide into smaller branches. These are the temporal, zygomatic, buccal, mandibular and cervical and together form pes anserinus (goose-foot). They supply all the muscles of facial expression.

29. तुम ज्यादा बकबक मत करो T um - T emporal Z yada - Z ygomatic B akbak - B uccal M at - M arginal Mandibular C aro – C ervical

30. SURGICAL LANDMARKS OF FACIAL NERVE During middle ear and mastoid surgery During parotid surgery

31. SURGICAL LANDMARKS OF FACIAL NERVE During middle ear and mastoid surgery 1. Processus Cochleariformis It demarcates the geniculate ganglion The geniculate ganglion lies just anterior to it. The tympanic segment of the FN starts at this level. 2. Oval Window and LSCC The facial nerve runs above the oval window (stapes) and below the LSCC 3. Short process of incus Facial nerve lies medial to the short process of incus at the level of aditus . 4. Pyramid Nerve runs behind the pyramid and the posterior tympanic sulcus. 5. Tympano -mastoid suture In vertical or mastoid segment, FN runs 6-8mm deep to tympanomastoid suture. 6. Digastric ridge Facial nerve leaves the mastoid at the anterior end of digastric ridge.

32. SURGICAL LANDMARKS OF FACIAL NERVE During parotid surgery 1. Cartilaginous pointer / Tragal pointer Tragal pointer is a sharp triangular piece of cartilage of the pinna and "points" to the nerve. The nerve lies 1 cm deep and slightly anterior and inferior to the Tragal pointer. 2. Tympanomastoid suture Nerve lies 6-8 mm deep to this suture. 3. Styloid process The nerve crosses lateral to styloid process But is deeper than the Facial nerve 4. Posterior belly of digastric If posterior belly of digastric muscle is traced backwards along its upper border to its attachment to the digastric groove, nerve is found to lie between PBD and the styloid process

33. 4. Electroneuronography

34. Causes of Facial paralysis Central Causes Brain abscess Pontine gliomas Poliomyelitis Multiple sclerosis Intracranial part (cerebellopontine angle) Acoustic neuroma Meningioma Congenital cholesteatoma Metastatic carcinoma Meningitis Extracranial part Malignancy of parotid Surgery of parotid Accidental injury in parotid region Neonatal facial injury (obstetrical forceps) Systemic diseases Diabetes mellitus Hypothyroidism Uraemia Polyarteritis nodosa Wegener's granulomatosis Sarcoidosis ( Heerfordt's syndrome) Leprosy Leukaemia Demyelinating disease  Intratemporal part - I DIOPATHIC Bell palsy  Melkersson syndrome - INFECTIONS Acute suppurative otitis media Chronic suppurative otitis media Herpes zoster oticus Malignant otitis externa - TRAUMA Surgical: Mastoidectomy and stapedectomy Accidental: Fractures of temporal bone - NEOPLASMS Malignancies of external and middle ear Glomus tumour Facial nerve neuroma Metastasis to temporal bone (from cancer of breast, bronchus, prostate)

35. Bell's Palsy 60-75% of all facial paralysis is due to Bell's palsy defined as “idiopathic, peripheral facial paralysis or paresis of acute onset” M = F Ay age Incidence increases with an increase in age Increased occurrence in elderly Diabetics and hypertensives than in common people Increased incidence in women during the 3 rd trimester of pregnancy 2 weeks before delivery and in first 2 weeks postpartum Bells palsy is recurrent in 3-10% of cases

36. Aetiology Viral infection – HSV 1, HZV,EBV, CMV, – polyneuropathy Vascular Ischemia – Primary / Secondary  Primary ischemia – induced by cold or emotional stress  Secondary ischemia – result of Primary ischemia which causes increased vascular permeability leading to exudation of fluid, oedema and compression of microcirculation of nerve Hereditary Fallopian canal is narrow due to hereditary predisposition it makes the nerve susceptible to early compression with the slightest oedema 10-15% of patient of bells palsy have positive family history Autoimmune disorder T-lymphocyte disorders

37. Sudden onset Unable to close eye Bells phenomenon – on attempting to close eye, eyeball turns up and out Saliva dribbles from angle of mouth Face becomes asymmetrical Watering eye (Epiphora) Pain in the ear my precede or accompany the nerve paralysis Loss of taste

38. Diagnosis By exclusion  all other possible causes of peripheral nerve paralysis should be excluded Careful history Complete Otological examination Complete head and neck examination Xray / CT Nerve Excitability test – done daily or on alternate days to compare with other side to monitor nerve degeneration Topodiagnostic test helps in localizing site of lesion

39. TREATMENT GENERAL TREATMENT Reassurance. Relief of ear pain by analgesics. Care of the eye - eye must be protected against exposure keratitis. Physiotherapy or massage of the facial muscles gives psychological support to the patient. Active facial movements are encouraged when there is return of some movement to the facial muscles .

40. MEDICAL MANAGEMENT Steroids Prednisolone is the drug of choice. If patient reports within 1 week, the adult dose of prednisolone is 1 mg/kg/day Contraindications - pregnancy, diabetes, hypertension, peptic ulcer, pulmonary tuberculosis and glaucoma Steroids have been found useful to prevent incidence of synkinesis, crocodile tears and to shorten the recovery time of facial paralysis. Steroids can be combined with acyclovir for Herpes zoster oticus or Bell palsy. Antiviral agents – Acyclovir , valacyclovir to start within 72 hr of onset Other drugs. Vasodilators, vitamins, mast cell inhibitors and antihistaminics have not been found useful.

41. SURGICAL TREATMENT Nerve D ecompression surgery relieves pressure on the nerve fibres and thus improves the micro-circulation of the nerve. Vertical and tympanic segments of facial nerve are decompressed.

42. PROGNOSIS 85 -95 % of the patients recover fully. 5-15 % recover incompletely and may be left with some stigmata of degeneration. Recurrent facial palsy may not recover fully. Prognosis is good in incomplete Bell palsy (95% complete recovery) and in those where clinical recovery starts within 3 weeks of onset (75% complete recovery)

43. Melkersson - Rosenthal Syndrome idiopathic disorder with triad of 1. R ecurrent facial paralysis 2. swelling of lips and 3. fissured tongue. Treatment - same as for Bell palsy.

44. Recurrent facial palsy Causes Bell palsy (3-10% cases) Melkersson syndrome D iabetes, S arcoidosis and T umours (Recurrent palsy on the same side may be caused by a tumour in 30% of cases) Bilateral facial paralysis Causes Guillain-Barré syndrome sarcoidosis sickle cell disease acute leukaemia bulbar palsy leprosy

45. Herpes Zoster Oticus (Ramsay-Hunt Syndrome) facial paralysis along with vesicular rash in the external auditory canal and pinna There may also be anaesthesia of face, giddiness and hearing impairment due to involvement of Vth and VIIIth nerves. Treatment - same as for Bell palsy.

46. TRAUMA - Fractures of Temporal Bone Fractures of temporal bone may be L ongitudinal, Transverse or mixed Facial palsy is seen more often in transverse fractures (50%) Paralysis is due to intraneural haematoma compression by a bony spicule or transection of a nerve It is important to know whether paralysis was of immediate or delayed onset. Delayed onset paralysis - treated conservatively like Bell palsy while I mmediate onset paralysis – may require surgery ( D ecompression, re-anastomosis of cut ends or cable nerve graft)

47. Iatrogenic - Ear or Mastoid Surgery / parotid surgery Facial nerve may get injured during stapedectomy, tympanoplasty or mastoid surgery Paralysis may be immediate or delayed Sometimes, nerve is paralyzed due to the pressure of packing on the exposed nerve and this should be relieved first. Facial nerve may be injured in surgery of parotid tumours or deliberately excised in malignant tumours. Accidental injuries in the parotid region can also cause facial paralysis. Application of obstetrical forceps may also result in facial paralysis in the neonate due to pressure on the extratemporal part of nerve. treatment - same as in temporal bone trauma

48. Iatrogenic injuries to facial nerve can be avoided if attention is paid to the following: Anatomical knowledge of the course of facial nerve, possible variations and anomalies and its surgical landmarks. Always work along the course of nerve (parallel to the nerve) and never across it. Constant irrigation when drilling to avoid thermal injury. Use diamond burr when working near the nerve. Gentle handling of the nerve when it is exposed, avoiding any pressure of instruments on the nerve. Not to remove any granulations that penetrate the nerve. Use magnification; never work on facial nerve without an operating microscope.

49. NEOPLASMS 1. Intratemporal Neoplasms Carcinoma of external or middle ear, glomus tumour, rhabdomyosarcoma and metastatic tumours of temporal bone, all result in facial paralysis. Facial nerve neuroma occurs anywhere along the course of nerve 2. Tumours of Parotid Facial paralysis with tumour of the parotid almost always implies malignancy

50. TOPODIAGNOSTIC TESTS for facial nerve These tests are useful in finding the site of lesion in paralysis of lower motor neuron SCHIRMER TEST  STAPEDIAL REFLEX TASTE TEST SUBMANDIBULAR SALIVARY FLOW TEST

51. COMPLICATIONS FOLLOWING FACIAL PARALYSIS Incomplete Recovery Exposure Keratitis Synkinesis Tics And Spasms Contractures Crocodile Tears (Gustatory Lacrimation) Frey's Syndrome (Gustatory Sweating) Psychological And Social Problems

52. SURGERY FOR FACIAL NERVE Decompression surgery End – to – end anastomosis Nerve graft (Cable graft) - ?? nerve Hypoglossal - facial anastomosis Plastic surgery - facial slings, face lift operation or slings of masseter and temporalis muscle