FRACTURE OF MALLEUS AND DISLOCATION OF MULTIPLE OSSICULAR JOINTS AFTER WELDING FLAME BURN - A CASE REPORT

Australian Journal of Oto-Laryngology, Jun 2004 by Liu, Wei, Zheng, Yiqing, Ou, Yonkang, Xu, Yaodong, Et al

We report a rare case of fracture of the malleus and multiple ossicular dislocation. The fracture and dislocation of the ossicular chain occurred in a welding worker who suffered from a welding flame bum and self-induced earpick trauma of his left ear. The fractured malleus was dug out by the patient shortly after the accident. Otoendoscopic examination revealed a near total perforation of the tympanic membrane and incus protrusion into the upper part of the external auditory canal. CT scanning indicated a corresponding abnormality of the middle ear. We believe that the welding spatter that fell into the ear canal induced a near total perforation of the tympanic membrane and possibly somehow loosened the ossicular chain. The subsequent self instrumentation by the patient caused further damage of the middle ear. We recommend that protection should be provided to both eye and ear for the welders.

Key words: Earpick; Welding flame; Ear trauma; Ossicular dislocation; ossicular fracture.

Introduction

Middle ear injuries can be induced by different aetiologies including temporal bone fractures, barotrauma, direct instrumentation, and surgical intervention. Among the publications of ossicular damage resulting from these causes, multiple ossicular dislocation and protrusion into the external canal are rarely reported [1]. Although earpick-induced ossicular damage has been reported in a substantial number of cases with separation of the incudostapedial joint,stapedial abnormality and perilymph fistula [2], no report linking earpick damage to the middle ear as seen in the case that we present here has been found in a Medline search. We report a rare case of fracture of the malleus and dislocation of multiple ossicles caused by earpick trauma in the wake of a welding flame burn of the ear canal and tympanic membrane.

Case report

A 35 year old man was referred to our hospital on 16th of January 2003 complaining of left ear pain and hearing loss one day after an accident in which welding spatter lodged in his left ear canal whilst he was working welding a ship. He had experienced severe pain in the ear immediately after the event. This gradually subsided over two hours. Some twenty minutes after the accident the patient used a spoonlike earpick to remove a bony fragment from deep in his ear canal and we identified this as the malleus that had been fractured at its manubrium (Figure 1). The patient denied any pre-existing ear symptoms, particularly otorrhoea, hearing loss, vertigo, tinnitus such as one may expect with otitis media or other ear disease. There was no vertigo after the accident as would usually occur with a perilymph fistula.

On examination we observed a healthy man with no other burns of the skin of the scalp, face or neck. Under otoendoscopy haemorrhagic tissue was identified at the inner end of the external canal but the tympanic membrane could not be identified.

Pure tone audiometry revealed a mixed hearing loss with a sensorineural component in the high frequencies (Figure 2).

High-resolution computer tomography (HRCT) of the temporal bone was performed and indicated some soft tissue opacity and disruption of the ossicular chain in the middle ear (Figure 3).

The patient was treated with oral antibiotic Cefzil (0.5g /day) and vitamin B preparations and scheduled for a second endoscopic examination after one week.

At the second examination haemorrhagic debris was removed from the deep part of the canal allowing identification of a near total perforation of the tympanic membrane. The incus was identified protruding through the defect with the lenticular process lying against the superior wall of the ear canal (Figure 4). This was left in place. There were no signs of active bleeding or leak of clear fluid. The antibiotic treatment was continued.

Tympanoplastic surgery has been scheduled for the near future.

Discussion

Tympanic membrane perforation and injury to the ossicular chain are frequently reported after head trauma, barotrauma and direct instrumentation, even including surgery. Ossicular injury usually occurs as separation of the incudostapedial joint, the incudomalleal joint and dislocation of the incus. Dislocation of the stapes from the oval window also occurs. The most common form of ossicular chain lesion following head injury is separation of the incudostapedial joint [3] while fractures of the malleus, incus or stapes are described as uncommon [4]. In Kojima's study of 10 ears from 10 patients with earpick-induced ossicular trauma, stapedial abnormality was seen more commonly than other ossicular dislocations (9/10 vs 5/10) [2].

The pattern of earpick-induced damage as seen in the present case with near total tympanic membrane perforation, a fracture dislocation of the malleus and dislocation of the incus is rare. Earpick-induced middle car trauma has been reported in a substantial number of cases [12]. However, none of the reported cases showed as extensive damage as seen in the current case.

In this case the welding flame burn is assumed to have damaged the tympanic membrane and perhaps caused some ossicular abnormalities. There was immediate pain but the earpick instrumentation added almost no extra pain. The earpick had a sharp spoonlike end that presumably acted like a surgical instrument.