Exostosis of the external auditory canal: an interesting histopathological finding

Imaging of Pathologies of the Temporal Bone and Middle Ear: Inflammatory Diseases, Their Mimics and Potential Complications-Pictorial Review

Imaging of the temporal bone and middle ear is challenging for radiologists due to the abundance of distinct anatomical structures and the plethora of possible pathologies. The basis for a precise diagnosis is knowledge of the underlying anatomy as well as the clinical presentation and the individual patient's otological status. In this article, we aimed to summarize the most common inflammatory lesions of the temporal bone and middle ear, describe their specific imaging characteristics, and highlight their differential diagnoses. First, we introduce anatomical and imaging fundamentals. Additionally, a point-to-point comparison of the radiological and histological features of the wide spectrum of inflammatory diseases of the temporal bone and middle ear in context with a review of the current literature and current trends is given.

[Osteomas and exostoses of external auditory canal in material of Otolaryngology Department Medical University of Gdańsk]

INTRODUCTION

Osteomas and exostoses of the external auditory canal are benign tumours arising in bones, leading to its obstruction and causing hearing loss. The treatment of these entities may present a therapeutic dilemma.

AIM OF THE STUDY

To assess epidemiological and clinical data and surgical treatment effectiveness.

SUBJECTS AND METHODS

The study group consisted of 21 patients (14 men and 7 women) between 18 to 63 years of age, treated in the Otorhinolaryngology Department of Medical University of Gdańsk from 1995 to 2009. The results of audiometric, radiological and histopathological examination were taken into consideration.

RESULTS

Unilateral osteomas developing in tympanosquamous suture in 5 patients, in tympanomastoid suture in 4. Bilateral exostoses occured in 12 patients in anterior, posterior and inferior wall of the external auditory canal. In all patients: conductive hearing loss ranged from 15 to 30 dB (average 29.9 dB), in 6 patients with concomitant sensorineural component. Osteomas were removed via intrauricular approach according to Mawson-Goodhill's method. Exostoses were removed via intrauricular, intracanal or postauricular approach. Histological examination confirmed benign overgrowth of compact and trabecular bone. The auditory canal was successfully reamed, the hearing improved in all patients.

CONCLUSIONS

Osteomas are benign tumours leading to obstruction of the external auditory canal. Exostosis is the overgrowth of the external auditory canal's compact bone in adults. Osteomas and exostoses may lead to hearing loss. Indications to surgical treatment are ear pain, progressive hearing loss and recurrent otitis external.

Osteotome technique for removal of symptomatic ear canal exostoses

OBJECTIVES/HYPOTHESIS

This study was undertaken to assess a transcanal osteotome technique for removing symptomatic ear canal exostoses. Outcome measures included healing rates and the rate of complications.

STUDY DESIGN

Prospective study in a private practice.

METHODS

A straight 1-mm osteotome and a curved 1-mm osteotome were used by way of a transcanal approach to incrementally remove obstructive ear canal exostoses. If anterior or superior bone growths were closely approximating the tympanic membrane, they were partially removed with a 1.5 mm cylindrical end- and side-cutting burr. Healing rates were monitored with weekly postoperative visits.

RESULTS

Two hundred twenty-one ear canals (140 patients) were consecutively treated with this technique. Healing was achieved at 2 to 8 (average 3.50) weeks, with 90% healed by 4 weeks. There were 4 mobilizations of a full-thickness segment of anterior bony canal wall; 3 exposures of periosteum anterior to the anterior bony wall; 1 tear of the tympanic membrane requiring a tympanoplasty; 18 anterior and 11 posterior tympanic membrane tears that healed spontaneously; 3 instances of sensorineural hearing decrease; 3 cases of new-onset postoperative tinnitus; and 1 instance of postoperative positioning vertigo. There were no lacerations of the tympanic membrane by an osteotome, no facial nerve injuries, no soft tissue stenoses of an ear canal, and no skin grafting of an ear canal.

CONCLUSIONS

The described technique of using osteotomes transcanal for removal of symptomatic obstructive ear canal exostoses promoted rapid healing and was effective and safe.

Exostoses of the external auditory canal: a long-term follow-up study of surgical treatment

To determine the postoperative incidence, extent and recurrence rate of exostoses of the external auditory canal in a cohort of patients involved in different water sports. A cross-sectional study of 31 patients (46 ears), with exostoses treated by surgery in the Royal Cornwall Hospital between 1980 and 1999. A questionnaire was used to obtain information about the type of water exposure pre- and postoperatively. The extent of recurrent stenosis was assessed. The mean postoperative time interval was 10 years (sd = 4.5 years). The degree of stenosis was assessed as: minimal (<30%) in 42.6%, moderate (30-60%) in 31% and severe (>60%) in 25% of ears. The Cox regression model was used to identify factors associated with a reduction in the recurrence rate of stenosis. The use of ear plugs was highly significant (P = 0.015), as was the age of the patient at the time of operation (P = 0.004), i.e. the older the patient, the faster recurrent disease developed. There was no evidence to show that either the type or seasonal pattern of water sport activity influenced recurrence of the disease postoperatively, although preoperatively, the stenosis was more marked in association with surfing and sailing. Exostoses developed faster preoperatively in those who were in the water all year round rather than just the summer months. Of five patients who stopped water sport activity completely after surgery, four of them developed significant recurrent exostoses (>50% stenosis).

Surgical emphysema: a novel complication of aural exostosis surgery

We present the case of a 40-year-old male Caucasian patient who developed surgical emphysema of the neck five weeks after surgery for exostoses of the external auditory canal. Imaging of the temporal bone demonstrated that the surgery had resulted in entry into the temporomandibular joint. A mechanism is proposed for this novel complication.