Clinical evaluation and surgical management of congenital preauricular fistulas

J Oral Maxillofac Surg X:827-830, 1998

Clinical Evaluation and Surgical Management of Congenital Preauricular Fistulas Maik Ellies, MD, * Rainer Laskawi, Christian Arglebe, PbD, f and Christina

MD,, AltroggeJ

Purpose: The retrospective investigation evaluated the clinical data on patients with a preauricular fistula with respect to demographic factors, symptoms, preoperative diagnosis, and surgical therapy. Follow-up studies served to critically assessthe outcome of the operations. Patients and Methods: The records of 62 patients were studied. Patients were divided into two groups: those operated on for the first time for a preauricular fistula and those operated on for a recurrence. Controlled follow-up was performed by means of a standardized questionnaire filled out by both the patients’ physicians and the patients themselves.

The mean age of patients operated on for the first time was 16 years, and that of patients Results: operated on for a recurrence was 22 years. Although the overall rate of recurrence was 21%, it differed widely between groups (14% in first operations and 42% in patients operated on for the first time for a recurrence). These figures are within the lower range of the recurrence rates previously reported. Serious side effects, such as persistent damage to the facial nerve, were not observed. Operative management of a preauricular fistula is a treatment with few side effects that should be offered to each patient with such a malformation. Because the first operation is decisive for the further course of the condition, surgery should be performed under optimum conditions to avoid recurrence.

Conclusions:

Preauricular fistulas are generally unsuspicious, symptom-free, congenital malformations that are visible in the preauricular region as small openings (Fig 1). The first published description dates back to 1864.l The incidence is low and varies with the ethnic group investigated (0.0% to 0.9%).2* A much higher incidence of between 4% and 10% of the population is reported for orientals and in some parts of Asia and Africa.5,6 Three theories of origin predominate. One frequently cited and generally accepted theory attributes preauricular fistulas to defective or incomplete fusion of the six auricular hillocks.’ This would make them relics of the former retractions between the auricular tubercles. Another theory states that fistulas of the

Received

from

of Glittingen,

the Department

of Otorhioolaryngology,

ascending helix, as well as preauricular fistulas, are relics of an incomplete closure of the dorsal part of the first pharyngeal groove. 8,9 This would mean that preauricular fistulas are branchiogenic malformations. According to a third theory, which is rarely mentioned in the literature, preauricular fistulas develop from isolated ectodermal folding during auricular development.lO Preauricular fistulas are apt to give rise to recurrent inflammation and recurrence after surgical extirpation. Earlier studies compiled clinical data but, because of the small numbers of patients, decisive questions, for instance, on demographic distribution and on the best therapy, are not yet fully answered. Our investigation tried to fill this gap.

University

Patients

Germany. Medical

*Research §Medical Address

Director.

Scientist. Student. correspondence

sitiits-HNO-Klinik,

and reprint

Robert-Koch-Str

requests 40,

D-37075

to Dr Ellies: UniverGGttingen,

Ger-

many. D 1998 American Association

of Oral and Maxillofacial

Methods

This study was based on the retrospective evaluation of the reports of 62 patients operated on for a preauricular fistula between 1970 and 1996 in the ENT Department of the University of Giittingen, Germany. The first part compiled data on anamnesis, symptoms, diagnosis, and therapy. In some patients, a bacteriologic smear was taken preoperatively and evaluated according to the written diagnosis of the Institute for Hygiene and Medical Microbiology of

*ENT Specialist. tAssistant

and

Surgeons

0278.2391/98/5607-0004$3.00/O

827

828

PREAURICULARFISTULAS

First Operation (n = 46) Symptoms

Palpable resistance Visible ostium Intlammation Itching Intermittent secretion Persistent secretion

FIGURE 1.

Preauricular

fistula.

the University of Gbttingen. The reports on the postoperative histologic findings made by the Institute of Pathology were treated in the same manner. The second part of the study evaluated the results of the follow-up undertaken on the operated patients. Data were collected by means of a standardized questionnaire sent to the patients’ physicians, containing questions regarding recurrence and possible sequelae of our therapy. In each case, the last actual date of examination was determined. In addition, all patients received the questionnaire, and some of them also underwent postoperative examination in the ENT department.

Results CLINICAL DATA Sixty-two patients with preauricular fistulas were treated in our department between 1970 and 1996. Forty-six were operated on for the first time and 16 had recurrences that had been operated on elsewhere before presenting for revision. The age of the patients with first operations varied between 1 and 59 years (mean, 16; median, 11 years). Twenty-one (46%) were male, and 25 (54%) were female. The age range of the patients operated for a recurrence for the first time was 3 to 57 years (mean and median, 22 years). In this group, 8 patients each were male and female. The fistulas were located bilaterally in 13 cases (21%) on the right side in 29 (47%) and on the left side in 20 cases (32%). Family anamnesis disclosed a familial predisposition to fistula formation in nine patients (14%). Mainly parents and siblings were affected; the number of family members involved varied from one to four. In the families of two

Recurrence Operation Total (n = 16) (n = 62)

n

%

n

%

n

%

10 26 33 2

22 57 72 4

6 lo 16 2

38 63

16

26

36

58

100

49

79

27 10

59 22

10 7

13 63 44

4 37 17

6 60 27

patients, lateral cervical fistulas or cysts were also present. All patients presented preoperatively with a fistula that had become symptomatic (Table 1). Before surgery, there had been single or multiple episodes of inflammation of the fistulas in 32 patients (52%) and in 21 patients (34%) one abscess or more had to be opened before fistula extirpation. A bacterial infection of the fistula was present in 11 cases (18%). The species responsible are indicated in Table 2. SURGICAL TECHNIQUE AND HISTOLOGIC FINDINGS The fistulas were extirpated in an infection-free interval. When the fistular duct was probed preoperatively, the length varied between 4 and 25 mm (mean, 14; median, 15 mm). Before extirpation, the ducts were injected with methylene blue, followed by oval circumscription of the orifice and extirpation of the entire length of the duct, aided by magnifying glasses or an operating microscope. In all cases, the orifice of the preauricular fistula was located at the level of the crus helicis or the ascending branch of the helix. Most fistulas followed the course taken by the external auditory meatus. One fistula opened into the external meatus at the transition between the cartilaginous and bony part. In four cases in which fistulas took a course toward the concha, portions of the auricular cartilage were also excised. Fistulas extended up to the parotid in three instances, and in one of them a lateral parotidectomy had to be performed because the lesion had formed a duct system within the gland. The histologic findings were evaluated on the basis

Pathogen Staphylococcus Staphylococcus

epidermidis aureus Streptococci (virz’dans group) Peptococcus Proteus sp.

n

%

4 4 2 2

31 31 15 15

1

8

829

ELLIESET AL of the written reports of the Institute of Pathology, 52 of which were available. Forty-eight fistulas (92%) were lined with multilayered, keratinized, squamous epithelium, which was lacking in four fistulas (8%). Table 3 summarizes the signs of inflammation found in the surgical specimens. Serious intraoperative or postoperative complications, such as bleeding or nerve injury, were completely absent. FOLLOW-UP STUDIES The follow-up period varied between 5 months and 26 years (mean, 13 years; median, 11 years 6 months) and included 47 patients (76%), 35 of whom belonged to the group of first operations and 12 to the group of recurrence operations. Within the follow-up period, 10 recurrences developed (Table 4), four of which were operated on again. These operations were performed between 3 and 9 months after reappearance of the symptoms (mean, 6 months; median, 5 months). Serious side effects of surgical therapy did not become apparent during follow-up.

Discussion The age and sex distribution of our patients with preauricular fistulas are in good agreement with those of previously published reports.9,11-15Twenty-one percent had a bilateral fistula. The corresponding figures from the literature vary between 17% and 47%.15-18 Because the number of patients studied by us was much larger than that of most other published reports, high percentages given for the incidence of bilateral fistulas must be viewed with caution. Familial disposition toward the occurrence of preauricular fistulas has been the subject of a number of investigations. The generally accepted hypothesis today postulates inheritance of fistula formation by an autosomal dominant allele with reduced penetrance and variable power of expression.11,19,20 In our study, too, the anomaly showed an increased incidence in

Symptoms No inflammation Acute inflammation Chronic nonspecific inflammation Chronic granulation and inflammation Chronic fibrosis and inflammation

First Operation (n = 34) n %

Recurrence Operation (n = 18) n %

Total (n = 52) n %

6 2

18 6

0 0

0 0

6 2

12 4

11

32

6

33

17

33

7

21

8

44

15

29

8

24

4

22

12

23

First Operation (n = 35) n % Recurrence Temporary sensory disorder Permanent sensory disorders Hypacusis Temporary pain Facial nerve deficit

5

14

1

30

2 1 1 0

6 3 3 0

Recurrence Operation (n = 12) n % 5

42

Total (n = 47) n % 10

21

3 1 3 0

6

012 I 0 2 0

8 0 17 0

: 0

the families of nine patients (14%), but our findings suggest incomplete dominance because in three cases the parents were not tiected, but children or other blood relations were. only approximately one third of all patients with asymptomatic fistulas are aware of their malformation.3J1 Clinically it may remain asymptomatic throughout their entire life span. However, in most cases, a yellowish-white secretion consisting of cellular debris is discharged, and intermittent secondary infections are observed. The leading symptoms are swellings and pain in the fistular region. 12~22 Discharge was observed in more than 80% of our patients, and indications of inflammation such as swelling, pain, or reddening were found in more than 70%. Our results therefore indicate a high susceptibility to infection of existing preauricular fistulas. The colonizing species most frequently described in the existing literature have included Streptococcus saliva&u, Staphylococcus pyogenes, gram-positive cocci, and gram-negative bacilli.23,24 In our patients, we found mostly Staphylococcus epidermidis and aureus, besides oral streptococci of the viridans group, peptococci, and Proteus species. Particularly S epidermidis and aureus are among the most frequent pathogens causing bacterial infections in humans. The presence in fistulas of oral streptococci could be explained, according to Klaber*3 by infections of the oral cavity or pharynx. The length of the fistula ducts measured preoperatively has been reported to vary between 3 and 22 mrr1.3~~~~J*~*~ We found lengths of up to 25 mm, confirming other observations also studying fistulas that had become symptomatic7J5 These values exceed those measured in asymptomatic fistulas,3xz1 confirming the hypothesis that inflammation of a fistula may lead to its elongation.3 This is important for the surgeon to know because most fistulas are operated on when infected, and thus greater depths of infiltration have to be expected. The current standard procedure for fistula excision is that described by Gohary et al,18 consisting of oval

830 circumscription of the malformation and subsequent exterpation of the prestained duct. We operated in the same way, aided by optical magnification or the operating microscope. The course taken by the fistulas corresponded, in most instances, to that described in the literature,12J4J5,25 but according to our experience, it is also possible that a fistula opens into the external auditory meatus or the parotid, with impending danger to the facial nerve. Fistulas are supposed to be lined nearly exclusively with squamous epithelium,5J4J7~24 an assumption verified by our results, because more than 90% of the fistulas observed by us contained squamous epithelium. Furthermore, we found signs of inflammation in 88% of preauricular fistulas. Statements concerning recurrence after fistula extirpation are very heterogeneous. Incidence rates from 13% to 42% have been reported after application of the standard surgical procedure previously described.12J7J8s26Other authors sometimes found lower, and sometimes much higher recurrence rates (up to 40%) after slight modification of the standard technique.7,12~~416,26 Th e validity of all these investigations suffers from the small number of cases (from 9 to 35) in each study. Especially for very small groups of patients, the recurrence rate has to be viewed with caution. A direct comparison is made very diflicult by the fact that the populations studied were sometimes very heterogeneous. We were able to investigate a comparatively large number of cases, all of them treated with a standardized operation technique. Our recurrence rate (21%) is in the lower range of previously reported rates. As might be expected, a striking difference becomes apparent when the groups of patients with first operations and with surgery for a recurrence are evaluated separately (Table 4). However, in both groups, serious sequelae, such as permanent damage to the facial nerve, were not observed. In conclusion, it can be stated that operative management of preauricular fistulas is a safe therapy with few side effects. In view of the fact that most fistulas become symptomatic during a person’s lifetime, treatment should be offered all patients with these malformations. Because the first operation is decisive for the later outcome, and to avoid subsequent recurrence, it should be performed by an experienced surgeon under optimum conditions. These include operation

PREAURICULAR

FISTULAS

in the infection-free interval and the use of optical magnification devices during surgery.

References

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12.

13.

14.

15. 16. 17. 18. 19. 20. 21. 22.

23. 24. 25. 26.

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