Cranial Nerve Lesion Acoustic Neuroma Presented By: Emma Morales Gigi Sanchez Christine Achenbach Josefina Delgado

Introduction of Cranial Nerve Eight: Vestibulocochlear Nerve b Arises in the inner ear and goes to the pons b Two anatomically and functional parts: fCochlear Nerve f Vestibular Nerve b Cranial Nerve XIII functions in hearing and balance

Vestibulocochlear Nerve VIII

Clinical Case of Acoustic Neuroma (Vestibular Shwannoma) b Robin European-American womanEuropean-American woman 51 years old51 years old Professional ExecutiveProfessional Executive Maintained reasonable dietMaintained reasonable diet Overall in perfectly good healthOverall in perfectly good health

Robin’s Symptoms Symptoms started 2 years agoSymptoms started 2 years ago –telephone communication distorted -right ear –tinnitus-right ear –dizzy spells at work –bumping into things everywhere

Robin’s visit to General Physician First General PhysicianFirst General Physician diagnosed her with inner ear imbalance from her last plane tripdiagnosed her with inner ear imbalance from her last plane trip Antivert medication was prescribed Antivert medication was prescribed no change in symptomsno change in symptoms Second PhysicianSecond Physician MRI scanMRI scan found small 0.9cm Acoustic Neuromafound small 0.9cm Acoustic Neuroma

Background: What is Acoustic Neuroma? b Non-cancerous tumor of the eighth cranial Nerve leading from brain to inner ear b Usually grow slowly over a period of years b Not Hereditary: Occur spontaneously without any evidence of inheritable patterns

Common Symptoms b Major symptom: Hearing Loss 95% of those with tumor b Tinnitus b Vertigo b Headaches b Unsteadiness-poor coordination b Facial numbness, tingling, twitching

Signs of Acoustic Neuroma b Decreased speech discrimination b Nystagmus b Abnormal facial electromyogram

Statistical Information b Found in autopsy in less than one in one-hundred of the general population b Hearing loss and symptoms occur in about one person in 100, 000 b Diagnosed in patients between the ages of b Cause unknown

Clinical Findings: Test b ENG (Electronystagmography test) Caloric Test b MRI scan

MRI Classification for AN b Entirely Intracanicular b Intercranial extension without brainstem distortion b Intracranial extension with brainstem distortion

Diagnosis: Findings on Clinical Case Detected small.9cm Acoustic Neuroma affected hearing loss and balance

Treatment Options b Observation b Surgery- Microsurgical tumor removal Partial tumor removalPartial tumor removal Total tumor removalTotal tumor removal b Radiation Gamma KnifeGamma Knife FSRFSR

Clinical Case Plan b Patient Robin decided on RADIATION b FSR treatment 5 treatments a week5 treatments a week for 5 weeksfor 5 weeks b Robin’s Follow-up 1 year - improved hearing1 year - improved hearing 2 years – tumor reduced and 92% hearing back2 years – tumor reduced and 92% hearing back no significant side effects no significant side effects

Neurobiology of Acoustic Neuroma: Structures Involved b Eighth Cranial nerve Vestibular & Cochlear DivisionsVestibular & Cochlear Divisions

Auditory Canal Auditory Canal

Internal Auditory Canal Internal Auditory Canal

Growth patterns b Stage 1 b Stage 2 b Stage 3