Temporal Bone Trauma: Temporal Bone Trauma October 12, 2005
Steven T. Wright, M.D.
Matthew Ryan, M.D. Temporal Bone Trauma: Temporal Bone Trauma Wide spectrum of clinical findings
Knowledge of the anatomy is vital to proper diagnosis and appropriate management Incidence and Epidemiology: Incidence and Epidemiology Motorized Transportation
30-75% of blunt head trauma had associated temporal bone trauma
More dismal prognosis
Inner ear decompression sickness
Blast Injuries Evaluation and Management: Evaluation and Management ATLS
H andamp; P
Thorough head andamp; neck examination
Physical Examination: Physical Examination Basilar Skull Fractures
Periorbital Ecchymosis (Raccoon’s Eyes)
Mastoid Ecchymosis (Battle’s Sign)
Physical Examination: Physical Examination Tuning Fork exam
Imaging: Imaging HRCT
Longitudinal fractures: Longitudinal fractures 80% of Temporal Bone Fractures
Lateral Forces along the petrosquamous suture line
15-20% Facial Nerve involvement
EAC laceration Transverse fractures: Transverse fractures 20% of Temporal Bone Fractures
Forces in the Antero-Posterior direction
50% Facial Nerve Involvement
Temporal Bone Trauma: Temporal Bone Trauma Hearing Loss
Facial Nerve Injuries Hearing Loss: Hearing Loss Formal Audiometry vs. Tuning Fork
71% of patients with Temporal Bone Trauma have hearing loss
CHL andgt; 40db suspicious for ossicular discontinuity
Hearing Loss: Hearing Loss Longitudinal Fractures
Conductive or mixed hearing loss
80% of CHL resolve spontaneously
Sensorineural hearing loss
Less likely to improve
Hearing Loss: Hearing Loss Tympanic Membrane Perforations
Ossicular fracture or discontinuity
Otic solutions may only mask CSF leaks Dizziness: Dizziness Fracture through the otic capsule or a labyrinthine concussion
Difficult diagnosis- bed rest, obtundation, sedation
Treatment: reserved for vomiting, limitation of activity
Allow for maximal central compensation
Dizziness: Dizziness Perilymphatic Fistulas
SCUBA diver with ETD
Fluctuating dizziness and/or hearing loss
Conservative treatment in first 10-14 days
40% spontaneously close
Surgical management for persistent vertigo or hearing loss
Regardless of visualization of fistula site, the majority of patients get better
Dizziness: Dizziness Inner Ear Decompression Sickness
Too rapid an ascent leads to percolation of nitrogen bubbles within the otic capsule.
Greater than 30 ft…. Decompression stages upon ascent are needed Dizziness: Dizziness BPPV
Acute, latent, and fatiguable vertigo
Can occur any time following injury
CSF Otorrhea: CSF Otorrhea Acquired
Bony defect theory
Arachnoid granulation theory Temporal bone fractures: Temporal bone fractures Longitudinal
80% of Temp bone fx
Anterior to otic capsule
Involve the dura of the middle fossa
Temporal bone fractures: Temporal bone fractures Transverse
20% of Temp bone fx
High rate of SNHL due to violation of the otic capsule
50% facial nerve involvement Testing of Nasal Secretions: Testing of Nasal Secretions Beta-2-transferrin is highly sensitive and specific
1/50th of a drop
Gold top tube, may need to send a sample of the patients serum also.
Found in Vitreous Humor, Perilymph, CSF
Electronic nose has shown early success
Very Accurate Imaging CSF Otorrhea: Imaging CSF Otorrhea High resolution CT
Heavily weighted T2
Slow flow MRI
Imaging: Imaging Slow flow MRI
Diffusion weighted MRI
Fluid motion down to 0.5mm/sec
Ex. MRA/MRV Treatment of CSF Otorrhea: Treatment of CSF Otorrhea Conservative measures
Bed rest/Elev HOBandgt;30
+/- lumbar drains
Assoc with hydrocephalus
Recurrent or persistent leaks Treatment of CSF Otorrhea: Treatment of CSF Otorrhea Brodie and Thompson et al.
820 T-bone fractures/122 CSF leaks
Spontaneous resolution with conservative measures
95/122 (78%): within 7 days
21/122(17%): between 7-14 days
5/122(4%): Persisted beyond 2 weeks
Temporal bone fractures: Temporal bone fractures Meningitis
9/121 (7%) developed meningitis. Found no significant difference in the rate of meningitis in the ABX group versus no ABX group.
A later meta-analysis by the same author did reveal a statistically significant reduction in the incidence of meningitis with the use of prophylactic antibiotics. Pediatric temporal bone fractures: Pediatric temporal bone fractures Much lower incidence (10:1, adult:pedi)
Undeveloped sinuses, skull flexibility
Prophylactic antibiotics did not influence the development of meningitis.
CSF Otorrhea Surgical Management: CSF Otorrhea Surgical Management Surgical approach
Status of hearing
Middle Cranial Fossa Overlay vs Underlaytechnique: Overlay vs Underlay technique Meta-analysis showed that both techniques have similar success rates
Onlay: adjacent structures at risk, or if the underlay is not possible Technique of closure: Technique of closure Muscle, fascia, fat, cartilage, etc..
The success rate is significantly higher for those patients who undergo primary closure with a multi-layer technique versus those patients who only get single-layer closure.
Refractory cases may require closure of the EAC and obliteration. Facial Nerve Injuries: Facial Nerve Injuries Loss of forehead wrinkles
Nasal tip pointing away
Flattened Nasofacial groove
Facial Nerve Anatomy: Facial Nerve Anatomy Facial Nerve Injuries: Facial Nerve Injuries Initial Evaluation is the most important prognostic factor
Onset and progression
Complete vs. Incomplete House Brackman Scale: House Brackman Scale Electrophysiologic Testing: Electrophysiologic Testing NET: Nerve Excitability Test
MST: Maximal Stimulation Test
Goal is to determine whether the lesion is partial or complete?
Neuropraxia: Transient block of axoplasmic flow ( no neural atrophy/damage)
Axonotmesis: damage to nerve axon with preservation of the epineurium (regrowth)
Neurotmesis: Complete disruption of the nerve ( no chance of organized regrowth)
Nerve Excitability TestMaximal Stimulation Test: Nerve Excitability Test Maximal Stimulation Test Stimulating electrodes are placed and a gross movement is recorded
Not as objective and reliable
andgt;3.5mA difference suggests a poor prognosis for return of facial function.
Correlates with andgt;90% degeneration on ENoG
Electroneuronography: Electroneuronography Most accurate, qualitative measurement
Sensing electrodes are placed, a voluntary response is recorded
Accurate after 3 days
Requires an intact side to compare to
Reduction of andgt;90% amplitude correlates with a poor prognosis for spontaneous recovery
Electromyography: Electromyography Electrode is placed within the muscle and voluntary movement is attempted.
Normal Muscle is electrically silent.
After 10-14 days, the denervated muscle begins to spontaneously fire:
Diphasic/Polyphasic potentials: Good
Loss of voluntary potentials: Bad
Facial Nerve InjuriesWHO GETS TREATMENT?: Facial Nerve Injuries WHO GETS TREATMENT? Conservative treatment candidates
Surgical treatment candidates
Facial Nerve Injuries: Facial Nerve Injuries Chang andamp; Cass
Medline search back to 1966
Individually reviewed each article
1) Understand the pathophysiology of facial nerve damage in temporal bone trauma.
2) What is the effect of surgical intervention on the ultimate outcome of the facial nerve.
3) Propose a rational course for evaluation and treatment. Facial Nerve InjuriesChang & Cass: Facial Nerve Injuries Chang andamp; Cass Pathophysiology based on findings by Fisch and Lambert and Brackmann:
Perigeniculate, Labyrinthine, and meatal segments
Concern over findings of endoneural fibrosis and neural atrophy proximal to the lesions
In an untreated human specimen found intraneural edema and demyelinization that extended proximally to the meatal foramen
33% bony impingement, 43% hematoma
Does Facial Nerve decompression result in superior functional outcomes compared with no treatment?: Does Facial Nerve decompression result in superior functional outcomes compared with no treatment? Not enough human data!
Boyle-monkey: prophylactic epineural decompression in complete paralysis did not improve recovery of facial nerve function after induced complete paralysis
Kartush: Prophylactic decompression of the meatal segment during acoustic neuroma decreased the incidence of delayed paralysis
Adour: compared patients with complete paralysis found:
Equal outcome with observation vs. decompression without nerve slitting
Worse outcome with decompression with nerve slitting
Does Facial Nerve decompression result in superior functional outcomes compared with no treatment?: Does Facial Nerve decompression result in superior functional outcomes compared with no treatment? Many difficulties in Study designs, controls, etc, but they made some rough estimates:
50% of patients who undergo facial nerve decompression obtain excellent outcomes
The true efficacy of facial nerve decompression surgery for trauma remains uncertain
Conservative Treatment Candidates: Conservative Treatment Candidates Chang and Cass
Present with Normal Facial Function regardless of progression
Incomplete paralysis and no progression to complete paralysis
Less than 95% degeneration by ENoG
Most data comes from Bell’s palsy/tumor studies by Fisch. Conservative Treatment Candidates: Conservative Treatment Candidates Brodie and Thompson
All patients that presented with normal facial nerve function initially that progressed to complete paralysis recovered to a HB 1 or 2. Surgical Candidates : Surgical Candidates Critical Prognostic factors
Immediate vs. Delayed
Complete vs. Incomplete paralysis
ENoG criteria Algorithm for Facial Nerve Injury: Algorithm for Facial Nerve Injury Facial Nerve InjuriesChang & Cass: Facial Nerve Injuries Chang andamp; Cass What time frame is best to operate?
Fisch-cats: Decompression of the nerve within a 12 day period resulted in 'excellent' functional recovery. Presumption was that it preserved endoneural tubules. (limits the damage to axonotmesis at worst)
Limits the accuracy of your patient selection because EMG is not reliable until day 10-14.
Surgical Approach: Surgical Approach Medial to the Geniculate Ganglion
No useful hearing
Middle Cranial Fossa
Lateral to Geniculate Ganglion
Transmastoid Surgical Approach: Surgical Approach Chang andamp; Cass
Severe facial nerve injury results in retrograde axonal degeneration to the level of the labyrinthine and probably meatal segments Surgical findings of greater than 50% nerve transection/damage: Surgical findings of greater than 50% nerve transection/damage Nerve repair via primary anastamosis or cable graft repair
HB 1 or 2: 0%
HB 3 or 4: 82%
HB 5 or 6: 18%
Iatrogenic Facial Nerve Injuries: Iatrogenic Facial Nerve Injuries Mastoidectomy (55%)
Bony Exostoses (14%)
Lower tympanic segment is the most common location injury
79% were not identified at the time of surgery
Management of Iatrogenic Facial Nerve Injuries: Management of Iatrogenic Facial Nerve Injuries Green, et al.
andlt;50% damage: perform decompression
75% had HB of 3 or better!
andgt;50% damage: perform nerve repair
No patients had better than a HB 3
Beware of local anesthetics
General consensus: acute, complete, postoperative paralysis should be explored as soon as possible.
Emergencies: Emergencies Brain Herniation
Pack the EAC
Carotid arteriography with embolization Bibliography: Bibliography Bailey, Byron J., ed. Head and Neck surgery- Otolaryngology. Philadelphia, P.A. J.B. Lippincott Co., 1993.
Brodie, HA, Thompson TC. Management of Complications from 820 Temporal Bone Fractures. American Journal of Otology; 18: 188-197, 1997.
Brodie HA, Prophylactic Antibiotic for Posttraumatic CSF Fistulas. Arch of Otolaryngology- Head and Neck Surgery; 123; 749-752, 1997.
Black, et al. Surgical Management of Perilymphatic Fistulas: A Portland experience. American Journal of Otology; 3: 254-261, 1992.
Chang CY, Cass SP. Management of Facial Nerve Injury Due to Temporal Bone Trauma. The American Journal of Otology; 20: 96-114, 1999.
Coker N, Traumatic Intratemporal Facial Nerve Injuries: Management Rationale for Preservation of Function. Otolaryngology- Head and Neck Surgery; 97:262-269, 1987.
Green, JD. Surgical Management of Iatrogenic Facial Nerve Injuries. Otolaryngolgoy- Head and Neck Surgery; 111; 606-610, 1994.
Lambert PR, Brackman DE. Facial Paralysis in Longitudinal Temporal Bone Fractures : A Review of 26 cases. Laryngoscope; 94:1022-1026, 1984.
Lee D, Honrado C, Har-El G. Pediatric Temporal Bone Fractures. Laryngoscope: vol 108(6). June 1998, p816-821.
Mckennan KX, Chole RA. Facial Paralysis in Temporal Bone Trauma. American Journal of Otology; 13: 354-261, 1982.
Savva A, Taylor M, Beatty C. Management of Cerebrospinal Fluid Leaks involving the Temporal Bone: Report on 92 Patients. Laryngoscope: vol 113(1). January 2003, p50-56
Thaler E, Bruney F, Kennedy D, et al. Use of an Electronic Nose to Distinguish Cerebrospinal Fluid from Serum. Archives of Otolaryngology; vol 126(1). Jan 2000, p71-74.