Exostoses

Sixty-four operations for removal of exostoses were analysed to determine the incidence of complications. Prolonged healing time was the most common complication, while infection and osteitis were the most serious. There was one case of stenosis postoperatively.

The usual healing time was one month, and any healing delayed for longer than three months was considered excessive. There were seven cases of prolonged healing, ranging from four months to eighteen months, before the canal was deemed to have healed. There were two herniations from the temporomandibular joint. One of these disappeared completely after three months. In the second case, the herniation is still present after a period of three years. It is not causing any occlusion of the external ear canal and can only be detected by movement of the anterior canal wall when opening the mouth.

There was only one perforation in this series, which was recognised at the time of surgery and repaired successfully immediately. There were no facial nerve injuries. One patient reported transient tinnitus postoperatively. In this series there were no sensorineural losses.

There were three major complications; two were due to infection causing osteitis and the other developed stenosis of the external ear canal. These all responded to treatment and the patients were not left with any disability.

Key words: exostoses, ear canal, deafness, otitis externa, surgery, complications.

Introduction

Surfing in Australia is a popular recreation as the majority of the population live along the coastal margin where fine weather, surf and beaches provide a wonderful environment for water sports. With the advent of the neoprene wetsuit surfing occurs all year round without a break over winter. This increases the exposure time of surfers' ears to immersion in cold water. Symptomatic exostoses of the external ear canal are therefore common in this part of the world1,2.

This review was undertaken to establish the complications that had occurred following surgery to remove exostoses from the external ear canal by the author over the previous ten years.

Patients and Methods

Sixty-four operations to remove symptomatic exostoses of the external ear canal in 49 patients were reviewed from 1991 to 2000. The author carried out all the reported operations.

Six operations were performed through a postauricular approach, the remainder were done via an endaural approach. There were 46 males and only 3 females. The average age was 39 at the time of the initial surgery; the youngest was 20 and the oldest 75. There were 37 right ears and 27 left.

Most patients were keen surfers or regular swimmers. They all had symptomatic exostoses, which caused either recurrent blocking of the ear canal with deafness; persistent conductive deafness or recurrent otitis externa. Asymptomatic exostoses that had to be removed to give access for stapedectomy or tympanoplasty have not been included.

Thirteen patients had surgery by the author on separate occasions on both sides.

Two patients had surgery for recurrent exostoses on the same ear by the author eight years and ten years after the initial procedure. Three patients had their exostoses removed by other surgeons prior to surgery by the author. One needed surgery fifteen years after the initial removal; another had surgery for his recurrent exostoses eight years later. The third patient had had two previous removals on both ears before undergoing surgery by the author. Overall he ended up having six operations on his ears.

Results

The average time to complete healing of the ear canal was one month, any time after three months was considered to be excessive and there were seven of these. In a few of these, granulations developed postoperatively. These responded to repeated removal as well as the application of ribbon gauze saturated in ointment containing Triamcinolone acetonide, Neomycin, Gramicidin and Nystatin.

Herniations from the temporomandibular joint occurred in two cases. One disappeared completely after three months while the other still has movement of the anterior canal wall when opening and closing the mouth three years after surgery. However the latter patient now has a normal ear canal and is not handicapped by the deformity.

One perforation was recognised at the time of exostoses removal and was repaired successfully immediately. There were no other perforations.

Transient tinnitus occurred postoperatively in one patient. He had a mild high frequency loss preoperatively but this did not change after surgery. No sensorineural hearing losses were recorded. Eight patients who had persistent conductive hearing losses ranging from 20 to 40 db losses had their hearing returned to normal postoperatively.

There were two serious infections requiring revision surgery to remove granulations and sequestering bone. This resulted in delayed healing of four and eighteen months in both cases.

One patient developed stenosis three months postoperatively. This was treated by injecting the stenosis with Triamcinalone acetonide on two occasions and dilating it with a Lempert's aural speculum.

Technique

After assessing both the postauricular and endaural approach early in this series the author decided the endaural approach gave adequate access to the larger anterior exostoses, the time taken to close the incision was less, the patient did not have to have their hair shaved and they did not need a cumbersome dressing applied at the end of the procedure.

A standard endaural incision is made passing through the incisura between the root of the helix and the tragus. This is then held apart with a self-retaining retractor. A circumferential incision is made just lateral to the exostoses. A further incision is made at 6 o'clock extending laterally from the circumferential one (Figure 1). Retrograde dissection is used to mobilise the skin lateral to the circumferential incision. These flaps are reflected and held apart by a further self-retaining retractor.

The skin over the exostoses is elevated medially as far as possible and the exostoses are hollowed out. The eggshell thin bone can then be fractured and removed. Large fragments are kept as they can be utilised at the end of the procedure to plug holes if either the mastoid air cells or the temporomandibular joint have been exposed.

Discs cut from a suture packet are used to protect the delicate skin and tympanic membrane from damage from the drill or the sucker.

It is easy to get lost when large exostoses are present so it is safer to work medially by taking down the posterior exostoses inferiorly as far as possible and then working on the anterior one. By moving from the posterior to the anterior exostoses and back again while keeping close to the floor of the external canal the hole gets bigger until the annulus is reached. The annulus is identified by using an elevator to probe between the skin and the exostoses as resistance is met once it is reached. The annulus can now be used as a landmark while drilling away the remaining exostoses. It is followed anteriorly and around until the whole tympanic membrane is exposed.

The proximity of the temporomandibular joint can be gauged by palpating the anterior wall with the stationary drill. As the joint is approached the anterior wall will tend to give when it is pushed. The mastoid air cells tend to appear bluish as the overlying bone is thinned. At the end of the procedure the aim is to be able to completely visualise the circumference of the tympanic membrane. The canal is thoroughly washed with irrigation solution to get rid of bone dust. The skin tube which remains attached all around to the annulus is usually too small now to completely line the expanded canal so it has to be slit so that it can be laid back to cover as much of the bony canal as possible. If there have been one or two holes made in the skin tube then the slits are made to try and include the holes in the incision line. Normally the skin tube is slit at 12 and 6 o'clock.

The drum is covered with a disc of Gelfilm and Gelfilm strips are used to line the external ear canal to facilitate packing the canal with pieces of BIPP impregnated gauze. The endaural incision is closed with 510 plain catgut and the remaining canal is packed with BIPP impregnated gauze.

The BIPP gauze is removed after a week. Drops containing Dexamethasone, Framycetin and Gramicidin are advised for the next two weeks. Total healing is usually completed within a month. If granulations develop postoperatively they are removed with cupped forceps and a ribbon gauze wick impregnated with Triamcinolone, Neomycin, Gramicidin and Nystatin is inserted for a week.

Surfers are then advised to protect their ears from further exposure to water by wearing earplugs, using a neoprene hood or wearing a helmet.

Discussion

It is now well recognised experimentally3,4 and epidemiologically5-11, that prolonged exposure of ears to cold water stimulates the formation of exostoses. It is interesting to note the male predominance 1,2,6,11-14 in most reviews of exostoses surgery. Surfing does seem to be more popular in males, but there still appears to be gender protection to the formation of exostoses in females and this needs to be studied further.

The symptoms produced by exostoses are prolonged blocked feeling of the ears after water activities with deafness and recurrent otitis externa. When these symptoms become annoying enough, surgical removal is advised. The decision to operate should not be undertaken lightly, as the removal of exostoses is time consuming and exposes the patient to a number of possible complications. Common complications that have been reported are delayed healing; perforation of the tympanic membrane, sensorineural hearing loss, tinnitus, fistula into the temporomandibular joint, facial nerve injury, infection, stenosis, fistula into the mastoid air cells, and recurrence2,12-t8. Surgical emphysema in the neck is an unusual complication of a fistula into the temporo-mandibular joint'9.

The best way to avoid complications is to work slowly and carefully with a constant awareness of the danger areas2,13,20,21. These are the temporomandibular joint anteriorly, the facial nerve posteroinferiorly mastoid air cells posteriorly, ossicles superiorly and the tympanic membrane medially.

As the temporomandibular joint is approached anteriorly, the bone becomes pink and can be indented with the sucker or the stationary drill. The irrigation solution causes refraction, which enables the operator to see around the corner anteriorly, and may give early warning that the temporomandibular joint is close by. If a small hole is made either into the temporomandibular joint or mastoid air cells it can be plugged with fragments of exostoses that have been fractured off during removal and saved.

The risk of sensorineural deafness can be minimised by avoiding contact with the lateral process of the malleus. The superior exostoses can extend deep to the pars flaccida and is best removed with a curette.

Preventing damage to the skin tube by the sucker or the drill can reduce delayed healing and risk of stenosis. Shields made out of either Silastic or cut-up suture packet will protect the skin tube and the tympanic membrane22.

Recurrence of exostoses can be reduced by adequate removal initially and encouraging surfers to protect their ears postoperatively by wearing either ear plugs or a neoprene hood. Exostoses have been observed to recur after removal even when surfing or swimming has discontinued after surgery.

Conclusion

Sixty-four operations for removal of exostoses were analysed to determine the incidence of complications. Prolonged healing time was the most common complication, while infection and osteitis were the most serious.

Surgical removal of exostoses is time consuming and has a significant incidence of complications. Surgery for this condition should not be undertaken unless the symptoms produced by the exostoses justify the risk of possible complication.

References

1 SCRIVENER B.P. Exostoses: How to get them right. J Otolaryng Soc Austral 1982; 5:67-70.

2 FISHER E.W., McMANUS T.C. Surgery for external auditory canal exostoses and osteomata. J Laryngol Otol 1993; 108:106-110.

3 HARRISON D.F.N. The relationship of osteomata of the external auditory meatus to swimming. Annals of the Royal college of surgeons of England 1962; 31:187-201.

4 FOWLER E.P., OSMUN P.M. New bone growth due to cold water in the ears. Arch Otolaryngol 1942; 36:455-466.

5 WONG B.J.F., CERVANTES W., DOYLE K.J., KARAMZADEH A.M., BOYS P., BRAUEL G., MUSHTAQ E. Prevalence of external auditory canal exostoses in surfers. Arch Otolaryngol Head Neck Surg 1999; 125:969-972.

6 CHAPLIN J.M., STEWART LA. The prevalence of exostoses in the external auditory meatus of surfers. Clin Otolaryngol 1998; 23:326-330.

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10 KENNEDY G.E. The relationship between auditory exostoses and cold water: A latitudinal analysis. Am J Phys Anthropol 1986; 71:401-415.

11 FABIANA M., BARBARA M., FILIPO R. External ear canal exostoses and aquatic sports. ORL 1984; 46:159-164.

12 SHEEY J.L. Diffuse exostoses and osteomata of the external auditory canal: A report of 100 operations. Otolaryngol Head Neck Surg 1982; 90:337-342.

13 WHITAKER S.R., CORDIER A., KOSJAKOV S., CHARBONNEAU R. Treatment of external auditory canal exostoses. Laryngoscope 1998; 108:195-199.

14 STOUGAARD M., TOS M. Less radical drilling in surgery for exostoses of the external auditory canal. Auris Nasus Larynx 1999; 26:13-16.

15 FRESE K., RUDERT H., MANNE S. Surgical treatment of external auditory canal exostoses. Laryngo-Rhino-Otolgie 1999; 78:537-543.

16 REBER M., MUDRY A. Results and extraordinary complications of surgery for exostoses of the external auditory canal. HNO 2000; 48:125-128.

17 PORTMAN D., RODRIGUES E., HERMAN D., LACHER G., BEBEAR J.P., PORTMAN M. Exostoses of the auditory canal: Clinical and therapeutic aspects. Rev Laryngol 1991; 112:231-235.

18 OOSTVOGEL C.W.F., HUTTENBRINK K.B. Recurrences of ear canal exostoses. Laryngo-Rhino-Otol 1992; 71:98-101.

19 VON BLUMENTHAL H., FISHER E., ADLAM D.M., MOFFAT D.A. Surgical emphysema: A novel complication of aural exostoses surgery. J Laryngol Otol 1994; 108:490-491.

20 GREEN J.D., SHELTON C., BRACKMAN D.E. Iatrogenic facial nerve injury during otologic surgery. Laryngoscope 1994; 104:922-926.

21 ADAD B., RASGON B.M., ACKERSON L. Relationship of the facial nerve to the tympanic annulus: A direct anatomic examination. Laryngoscope 1999; 109:1189-1192.

22 LeLIEVER W.C. Flap protection in exostoses surgery. Laryngoscope 1985; 95:1126-1127.

WILLIAM B. HURST

Frankston Hospital Victoria Australia

William B. Hurst F.R.C.S.(Ed) F.R.C.S.(Eng) F.R.A.C.S. From the Department of Otolaryngology, Frankston Hospital, Victoria, Australia.

Address for correspondence: William B Hurst 45 Hastings Rd. Frankston 3199 Victoria, Australia.

Copyright Australian Society of Otolaryngology Head & Neck Surgery Ltd. Oct 2001
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