New Study Identifies Specific Ear Problems Resulting From Automobile Airbag Deployment

The downside of airbag deployment is the introduction of a new spectrum of injuries. Most are minor, but some can be life threatening. These injuries include eye damage and trauma to the spine, facial nerve and facial skeleton. Of particular interest to the otolaryngologist-head and neck surgeon are injuries to the head and neck area. Two Michigan-based otolaryngologists, William McFeely, MD, and Dennis Bojrab, MD, have reviewed the case histories of patients suffering hearing problems and balance disturbances after airbag deployment. Their findings are to be presented before the 1998 American Academy of Otolaryngology-Head and Neck Surgery Foundation (AAO-HNSF) Annual Meeting and OTO Expo, which is being held September 13-16 at the Henry B. Gonzalez Convention Center in San Antonio, TX.

Methodology

Twenty patients with ear or hearing disorders following an airbag deployment between April, 1996, and April, 1998, were retrospectively studied. A chart review was conducted, and a telephone questionnaire was utilized to acquire any missing data.

Each patient received a complete neuro-otologic examination. Pure tone and speech audiometry was performed post-accident and periodically after initial evaluation of all subjects. Audiometric testing carried out was divided into two groups: early (less than one month) and late (more than one month) after the motor vehicle accident. Driver inboard (right) ears were considered as oriented towards a deploying passenger side airbag when the overall head positioning was straight ahead.

Results

The average age of the 20 patients was 48 years. Nearly all the individuals were driving and the driver side airbag deployed in all accidents studied. Nine passenger-airbags also deployed. All were wearing seatbelts, although one child was improperly restrained. Follow-up visits averaged 18 months; no patient sustained a skull-base fracture or significant head injury. Three of the patients had been operated on before the accident for chronic ear disease. Other pre-accident conditions included mild, subjective hearing loss (nine patients), infrequent tinnitus (three patients) and one patient had intermittent disequilibrium.

After the airbag deployment:

New onset hearing loss in 17 of 20 patients, and non-pulsatile (non-throbbing) tinnitus (17/20) was the most common symptoms reported after the accident.

Subjective hearing loss occurred in one ear (10 of 17 patients), in both ears (7/17), and persisted in 13 of 17 patients.

Having the ear turned toward a deploying airbag increased the chances of hearing loss and eardrum performation.

Tinnitus was reported in one ear (11 of 17 patients), in both ears (6/17), and persisted in nine of 17 patients.

Disequilibrium, or dizziness, occurred in 10 of 20 patients. Of that group, six had a temporary condition; four had a persistent condition.

Four of the subjects had a perforation of the tympanic membrane; surgical intervention was required.

High frequencies were most affected for patients with hearing loss.

The authors suggest that side airbags recommended for new vehicles may increase the chances of otologic injuries. They also suggest that physicians treating victims of motor vehicle accidents should take ear injuries into consideration when offering emergency care.

The American Academy of Otolaryngology-Head and Neck Surgery Foundation Annual Meeting and OTO Expo is being held in San Antonio, TX, from September 13-16. More than 8,000 participants are expected for scientific sessions, exhibits, posters, and a research program.