Non-explosive blast injury of the tympanic membrane in Umuahia, Nigeria.

BACKGROUND

To examine the clinical features and causes of non-explosive blast injury to the ear, as well as the frequency of the State police involvement.

METHOD

Prospective clinical study of consecutive patients with traumatic tympanic membrane perforations resulting from non-explosive blast trauma to the ear without history of previous middle ear disease who attended ENT clinic of Federal Medical Center Umuahia. Clinical features and causes of non-explosive blast injury to ear; healing outcome at 2, 4, 8, and 12 weeks; perforation size versus healing outcome and cause of injury were the main outcomes measured.

RESULTS

Five hundred and ninety three new patients with aural disease were analysed. Sixty-one patients, (38 males and 23 females), aged 10-56 years had tympanic membrane perforation from non-explosive blast injury to the ear. The commonest symptoms were hearing loss (64%), tinnitus (61%), and ear ache (57%). The causes of injury were: slap against the ear by State police (31%), spouse (28%), armed bandits (18%), school teachers (8%), parents (5%), and blow against the ear during street fight (10%). Ninety two percent of the perforations healed spontaneously Healing was associated with significant closure of air bone gap (t = 15.08; p < 0.01). Non-healing of perforation was significantly associated with the large perforations occupying estimated 50% or more of the entire tympanic membrane area (chi2 = 8.67; p = 0.003).

CONCLUSION

The ear is very susceptible to injury from non-explosive blast trauma. There was a high spontaneous healing rate of the resulting tympanic membrane perforation, favoring conservative management in most of the case. Non-healing was associated with large-sized perforations. Abusive slap by the State police men was the commonest cause of non-explosive blast injury to the tympanic membrane. Our results are hoped to stimulate a change in the attitude of the culprits and lead to a reduction in the incidence of avoidable TM perforations from slap assaults.