Abstract
Pre-auricular sinus usually presents in front of the auricle without any diagnostic dilemma. But confusion arises when it presents with post-auricular swelling, abscess or discharging sinus. Here we describe series of pre-auricular sinus with post-auricular extension, a “variant type” of pre-auricular sinus and their management. A prospective study was done in the department of ENT in a tertiary care hospital of West Bengal from April 2015 to March 2018. After control of infection and proper pre-operative investigations patients, sinus was excised using bi-directional approach. The sinus tract along with a thin rim of conchal cartilage and pre and post-auricular cuff of skin was excised in toto. Among 76 cases of pre-auricular sinus, seven had “variant type”. There were five males and two females in the variant group. Five patients were in the first decade of life and two patients were in the second decade of life. Four patients presented with post-auricular scar, two patients presented with post-auricular discharging sinus and one patient presented with post-auricular abscess. Wound healing was perfectly normal in all patients. None had recurrence till 1 year follow up. Pre-auricular sinus may present as “variant type” with post-auricular abscess or discharging sinus. So when a patient presents with post-auricular abscess or discharging sinus, pre-auricular region and pinna should be examined carefully. This helps to avoid unnecessary investigations and interventions which only complicate future management of these patients.
Keywords: Pre-auricular sinus, Variant type, Recurrence, Bi-directional approach
Introduction
Pre-auricular sinus (PAS) is a common congenital anomaly in children which was first described in 1864 by Heusinger [1]. Mostly it presents in front of the auricle without any diagnostic dilemma. But confusion arises when it presents with post-auricular swelling, abscess or discharging sinus [2]. The vast majority of PAS are asymptomatic and do not require treatment. However, in post-auricular variety, surgical excision is recommended because the likelihood of recurrent infections is high [2]. Simple excision of the sinus is not sufficient in these cases. It requires bi-directional approach from both pre and post-auricular sides [3]. Here we describe series of pre-auricular sinus with post-auricular extension, a “variant type” of pre-auricular sinus and their management.
Materials and Methods
A prospective study was done in the department of ENT in a tertiary care hospital of West Bengal from April 2015 to March 2018. In this period total 82 cases of pre-auricular sinus were treated. Among them six patients were lost in follow up. So we excluded them from our study. Informed consent was taken from each patient or his/her guardian, after approval of the study by Institutional Ethical Committee. Among 76 patients, seven patients had pre-auricular sinus with post-auricular extension. History of swelling and discharge behind the ear, hearing loss and ear discharge, previous surgery or any systemic disease were taken. Thorough examination of pinna, pre and post auricular region, external auditory canal and tympanic membrane were done. Audiological tests and X-ray both mastoids lateral oblique view were done. Patients with post-auricular abscess or perichondritis were treated with broad spectrum antibiotics and analgesics. After control of infection and proper pre-operative investigations patients were posted for operation under general anaesthesia. Local infiltration with 2% lignocaine and 1:2,00,000 adrenaline was done into both pre and post auricular incision lines. Diluted methylene blue was injected in the pre-auricular opening. Elliptical incision was given around both pre-auricular pit and post-auricular scar. Sharp dissection was done from both pre and post auricular sides till the blue lined tract was visualized. The tract was followed and seen extending through the conchal cartilage. The sinus tract along with a thin rim of conchal cartilage and pre and post-auricular cuff of skin was excised in toto (Fig. 1). Wound was closed and mastoid bandage was given. Post-operative period was uneventful in all cases. Stitches were removed after 1 week. Patients were followed up for a minimum of 1 year.
Fig. 1.
Intra-operative picture showing (a) sinus tract going through conchal cartilage and (b) excision of sinus with cuff of post-auricular skin
Results
In this study, there were seven cases of “variant type” of pre-auricular sinus among total 76 cases of pre-auricular sinus (Table 1). There were five males and two females in the variant group. Among them five patients were in the first decade of life and two patients were in the second decade of life. There was history of incision and drainage for post-auricular abscess in three patients. Five of them had lesion on right side and two had on left side. Four patients presented with post-auricular scar (Fig. 2), two patients presented with post-auricular discharging sinus (Fig. 3) and one patient presented with post-auricular abscess (Fig. 4). All of them had pre-auricular pit on the ascending limb of helix. Wound healing was perfectly normal in all patients. None had recurrence till 1 year follow up.
Table 1.
Distribution of patients according to age, sex, side of involvement and presentation
| Serial number | Age | Sex | Side | Presentation |
|---|---|---|---|---|
| 1 | 5 years | Male | Right | Post-auricular scar |
| 2 | 7 years | Male | Right | Post-auricular discharging sinus |
| 3 | 14 years | Female | Left | Post-auricular abscess |
| 4 | 8 years | Male | Left | Post-auricular scar |
| 5 | 7 years | Male | Right | Post-auricular scar |
| 6 | 17 years | Female | Right | Post-auricular scar |
| 7 | 4 years | Male | Right | Post-auricular discharging sinus |
Fig. 2.
Right ear showing (a) pre-auricular pit and (b) post-auricular scar
Fig. 3.
Right ear showing (a) pre-auricular pit and (b) post-auricular discharging sinus
Fig. 4.
Left ear showing (a) pre-auricular pit and (b) post-auricular abscess
Discussion
Pre-auricular sinus (PAS) is the most common variant of all peri-auricular cysts, fistulas, and sinuses [4]. The pinna is formed by mesoderm and ectoderm from the first and second branchial arches and first branchial cleft. During the sixth week of embryonic development, mesenchymal proliferation produces the six hillocks of His. Three hillocks gather on the caudal aspect of the first branchial arch, and another three on the cephalic aspect of the second branchial arch. The hillocks eventually enlarge and fuse to form the pinna. With growth of the auricle, the contribution of the first branchial arch becomes relatively reduced [5]. The exact embryologic basis of pre-auricular sinuses is uncertain. They may be related to an incomplete fusion of the first arch hillocks, an entrapment of ectodermal folds during auricular formation, or a defective closure of the dorsal portion of the first branchial cleft [5].
It has an estimated incidence of 0.1 to 10% with higher incidence among Asians and Africans [6]. Fifty percent cases of PAS are unilateral, occur sporadically and are on right side [7]. Bilateral cases are usually inherited and the pattern is of autosomal dominant with reduced penetrance and is linked to chromosome 8q11.1 to q13.3 [8]. PAS may also be related to branchiogenic fistulas, hearing loss and renal malformations [2].
The cutaneous pit of the pre-auricular sinus is most often located on or near the ascending limb of the helix but can also open along the postero-superior margin of the helix as well as the tragus and lobule [9]. While both cutaneous opening and fistulous tracts are classically located anterior to the external auditory canal, a reported “variant type” has its opening behind an imaginary vertical line drawn at the posterior most aspect of the tragus and the posterior aspect of the ascending limb of the helix [3]. Choi et al. [3] reported that the “variant type” of pre-auricular sinus comprised 10.9% of pre-auricular sinus, that all fistulas were located on the ascending helix, and that the fistulous tract was directed posteroinferiorly. In this study, the variant group was 9.21% (7/76) of all patients, which is similar to Choi et al. This “variant type” typically presents with post-auricular swelling which may be confused with other pathology like post-auricular lymphadenitis, sebaceous cyst, dermoid cyst, mastoid abscess, perichondritis [10, 11].
The principles of treatment of PAS are complete excision of the pit, sinus and sac during the period of quiescence after treating active infection with antibiotics [2]. Various techniques of excision of classical PAS include simple sinectomy approach, supra-auricular approach, facelift approach and inside out approach [12–14]. PAS is notorious for recurrence due to difficult identification of multiple ramifications, scarring and fibrosis, as well as their close proximity to perichondrium [11]. In the present case series, we faced with the problem of how to approach surgically. If the exposure is via classical pre-auricular approach, then we would risk recurrence by leaving behind bits of the sinus tract. Since the pinna receives majority of its blood supply from anterior auricular artery (branch of auriculotemporal artery), superior auricular artery (branch of middle temporal artety), and posterior auricular artery; there is risk of devascularisation of the pinna with extended supra-auricular approach [15]. The facelift incision would need extensive dissection inferior to the external auditory canal and have difficulty in exposing the tissue superior to external auditory canal [16]. The post-auricular incision is a familiar one often used for approaching the middle ear. It preserves anterior auricular vessels and superior auricular vessels saving the surgeon from the anxiety of leaving behind a devascularized pinna [17]. In the present case series, we used bi-directional approach, which included pre and post auricular incisions with cuff of skin around the puncta or scar. This gave adequate exposure to the entire lesion from post-auricular groove to temporalis fascia antero-superiorly. Post-operative cosmesis was improved since the incision was in the post-auricular groove in a tension free region. The pre-auricular incision was small and hidden in the skin crease.
Conclusion
Pre-auricular sinus may present as “variant type” with post-auricular abscess or discharging sinus. So when a patient present with post-auricular abscess or discharging sinus, pre-auricular region and pinna should be examined carefully. This helps to avoid unnecessary investigations and interventions which only complicate future management of these patients.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest
Ethical approval
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent
Informed consent was obtained from all individual participants included in the study.
Footnotes
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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