Treatment of blast injury to the ear

Otologic assessment of blast and nonblast injury in returning Middle East-deployed service members

OBJECTIVES/HYPOTHESIS

To determine if tympanic membrane perforation offers any protection from inner ear damage and determine the incidence and pattern of otologic blast injury in military personnel returning from deployment.

STUDY DESIGN

Retrospective analysis of US service members injured in Operation Iraqi Freedom and Operation Enduring Freedom from October 2006 to October 2007.

METHODS

One-hundred ten blast-injured patients were compared to 54 nonblast-injured patients returning from deployment. Data captured included audiogram results, presence of tympanic membrane perforation, demographic data, location and nature of injury, loss of consciousness, sleep disturbance, confusion, and symptoms of headache, dizziness, memory loss, and tinnitus.

RESULTS

Of 110 blast-injured patients, 18 patients suffered tympanic membrane perforation (16%), of which nine patients suffered bilateral tympanic membrane perforation (8%). Blast patients suffered more hearing loss than controls as measured by pure-tone averages of varying speech reception frequencies and at 6,000 Hz. Of the blast patients who recorded an audiogram, nearly 24% suffered moderate to profound hearing loss. There was no statistically significant difference in hearing outcomes between blast-injured patients with tympanic membrane perforations and those without; however, when comparing patients with unilateral perforations with their contralateral ear, there was a difference in hearing thresholds at 6,000 Hz. There was a significantly increased risk of tinnitus, memory loss, headache, and dizziness between blast-injured patients compared to controls.

CONCLUSIONS

Due to its violent nature, blast exposure causes greater neuro-otological manifestations and deserves prompt otologic evaluation.

Effect of treatment at different time intervals for traumatic tympanic membrane perforation on the closure

CONCLUSION

Treatment of traumatic tympanic membrane (TM) perforation with everted or involute edge flaps at different time intervals within 1 week after the injury did not affect the perforation closure rate and mean closure time.

OBJECTIVE

To retrospectively analyze the effect of treatment at different time intervals for traumatic tympanic membrane perforation with gelatin sponge patch and edge approximation plus gelfoam patching.

METHODS

Patients with traumatic TM perforation visited at different days since the injury for medical treatment (1, 2, 3, 4, and 5-7 days post trauma). These patients were treated with the following prominent methods of treatment: gelatin sponge patch treatment and edge approximation plus gelfoam patching. Measurement indicators were perforation closure rate and mean closure time at 3 months.

RESULTS

In the group treated with the gelatin sponge patch technique, the patients sought medical treatment at different time intervals since the injury. Accordingly, the outcome of the treatment varied in terms of the perforation closure rates achieved in different patients in this group. The respective perforation closure rates were 100%, 100%, 96%, 94%, and 89% in accordance with the time interval at which the patients were treated since the injury. The results were not significantly different when compared by statistical analysis (p > 0.05); the mean closure times in each of the different sets of cases in this group were calculated and the following values were reported: 7.1 ± 2.3, 8.2 ± 1.6, 8.7 ± 1.2, 9.2 ± 3.1, and 10.7 ± 3.9 days. On the other hand, in the edge approximation plus gelfoam patching group, the perforation closure rates were 100%, 97%, 96%, 97%, and 94%, respectively. This was in accordance with the time elapsed since the injury for the patients who visited the hospital on different days. Statistical analysis confirmed that the perforation closure rates for the different cases of this group did not have any significant difference (p > 0.05); the mean closure times were 7.6 ± 1.9, 7.9 ± 2.2, 9.2 ± 2.8, 8.5 ± 3.6, and 11.2 ± 4.1 days, respectively, indicating that differences were not significant even in terms of mean closure rates for the different cases of this group (p > 0.05).

Blast injuries

Health-care providers are increasingly faced with the possibility of needing to care for people injured in explosions, but can often, however, feel undertrained for the unique aspects of the patient's presentation and management. Although most blast-related injuries (eg, fragmentation injuries from improvised explosive devices and standard military explosives) can be managed in a similar manner to typical penetrating or blunt traumatic injuries, injuries caused by the blast pressure wave itself cannot. The blast pressure wave exerts forces mainly at air-tissue interfaces within the body, and the pulmonary, gastrointestinal, and auditory systems are at greatest risk. Arterial air emboli arising from severe pulmonary injury can cause ischaemic complications-especially in the brain, heart, and intestinal tract. Attributable, in part, to the scene chaos that undoubtedly exists, poor triage and missed diagnosis of blast injuries are substantial concerns because injuries can be subtle or their presentation can be delayed. Management of these injuries can be a challenge, compounded by potentially conflicting treatment goals. This Seminar aims to provide a thorough overview of these unique primary blast injuries and their management.

Tympanic membrane perforation and hearing loss from blast overpressure in Operation Enduring Freedom and Operation Iraqi Freedom wounded

BACKGROUND

Tympanic membrane perforation is the most common primary blast injury in the current conflicts and occurs in approximately one tenth of service members wounded by combat explosions. We wanted to determine the severity of perforation and its effect on hearing and combat readiness.

METHODS

This analysis is a retrospective study of US service members injured in combat explosions in Afghanistan or Iraq and treated at our institution between March 2003 and July 2006. Data captured included location and grade of perforation, symptoms, healing rates, audiogram results, need for hearing aids, and loss of eligibility for military service.

RESULTS

Of 436 explosion-wounded patients admitted to our facility, 65 (15%) patients had tympanic membrane perforation diagnosed by the otolaryngology service. A total of 97 tympanic membrane perforations occurred among 65 patients. The average surface area involved was 41% +/- 32% (right) and 35% +/- 34% (left). More than one third of perforations were grade 4. The most common locations were central and anterior-inferior. Most (83%) patients reported symptoms, most commonly diminished hearing (77%) and tinnitus (50%). Outcome data were available for 77% of perforations. Spontaneous healing occurred in 48%. The remainder (52%) had surgical intervention. The most common audiogram abnormality was mild high frequency hearing loss. Ultimately, three patients (5%) required hearing aids and one discharge from military service.

CONCLUSIONS

Tympanic membrane perforation occurs in 16% of explosion-injured patients. Most patients are symptomatic and many have large perforations requiring operative intervention. Long-term hearing loss is uncommon but does impact ability to continue military service.

Otologic injuries caused by airbag deployment

Airbags are clearly successful at mitigating injury severity during motor vehicle accidents. Deployment unfortunately has introduced new injury-causing mechanisms. A retrospective review of 20 patients who sustained otologic injuries resulting from airbag inflation was conducted. The most common symptoms were hearing loss in 17 (85%) and tinnitus in 17 (85%). Objective hearing loss was documented in 21 of 24 (88%) subjectively affected ears; this included unilateral and bilateral sensorineural, unilateral conductive, and mixed hearing losses. Ten patients (50%) had dysequilibrium. Four subjects (20%) had a tympanic membrane perforation; each required surgical closure. Ear orientation toward the airbag was found to be associated with hearing loss (P = 0.027), aural fullness (P = 0.039), and tympanic membrane perforation (P = 0.0004). A wide variety of airbag-induced otologic injuries occur and may have long-term sequelae. It is important for health care personnel to be aware of these potential problems.

Spontaneous healing of traumatic tympanic membrane perforations in man: a century of experience

Widespread controversy exists concerning the treatment of traumatic tympanic membrane perforations. To elucidate the issue, a reference value for the rate of spontaneous tympanic membrane closure in man, to which the healing rates following different techniques of early surgical repair should be compared, was established on the basis of a review of more than 500 texts covering a century's literature on the traumatically perforated tympanic membrane. The spontaneous healing rate appeared to be close to 80 (78.7 per cent) in 760 evaluable cases of traumatic tympanic membrane perforations of all sorts diagnosed within 14 days post injury. A relative, causal-related variation of spontaneous healing could be demonstrated, and a pathogenetic classification of direct traumatic tympanic membrane perforations into ruptures induced by air-pressure changes, heat or corrosives, solids, and water pressures, is of proved clinical value and may have medico-legal validity. There is an obvious need for clinically controlled studies on the spontaneous healing of all kinds of traumatic perforations of the tympanic membrane in humans, and important elements in the design of future studies are advocated.