Polisetti Ravibabu1, Mitta Sreenivasulu2, Bhennur Durgaprasad3, Lanke Sowmya4

PAS (Preauricular Sinus) is a common congenital condition of external ear. It is seen in front of external ear as a small dimple or pit. When infected, it presents as swelling with pain and discharge from sinus with foul smell. There are many terminologies used for this condition like preauricular pit, preauricular tract and helical fistula.1 It was first described by Heusinger in 1864.2 It is more often unilateral than bilateral. Right side is more involved and females are more affected than males.3 PAS is an embryological malformation associated with development of pinna in 6th week of gestation. Embryologically six mesenchymal hillocks form the auricle - three hillocks from first arch and three hillocks from the 2nd arch. These hillocks fuse to form the pinna and incomplete fusion of these hillocks give rise to preauricular sinus.1 Another theory states that PAS develops from ectodermal folding.(4,5,6)
The rationale of this study is to highlight the surgical advantage achieved with the aid of operating microscope combined with standard surgical techniques.
A prospective longitudinal study was conducted in the department of ENT, Santhiram Medical College and General Hospital, Nandyal between November 2013 and March 2015. A total of 7 patients were diagnosed with preauricular sinus and were planned for excision. A thorough ENT examination was done and the syndromes commonly associated with PAS were ruled out. All patients were examined by a physician for systemic diseases and were declared fit for surgery. All the cases were operated by first author under local anaesthesia. Surgery was done using simple elliptical incision around preauricular sinus pit and dissection proceeded with the aid of operating microscope (Carl Zeiss, Movena).
Out of 7 patients, 5 were females and 2 were males. 6 were unilateral and only one case was bilateral, 4 cases were right sided and 2 were left sided. Two patients had scars of incision and drainage done previously for abscess formation. All were primary cases. None of the cases were part of any syndromes associated with PAS. Patients were aged between 15 yrs. to 45 years. Followup period was between 9 months to 2 years. Six patients presented with quiescent stage of disease and were considered for immediate surgery. One female patient presented with abscess formation and facial cellulitis. Incision and drainage was done for the patient and surgery had to be deferred for 3 months to get rid of the residual infection.
PAS (Preauricular Sinus) is a common congenital condition of external ear. PAS is multibranched and has several ramifications. Hence it is prone to recurrence if the tract is not completely excised. Microscopic magnification combined with methylene blue dye gives a better result. Preauricular soft tissue is dissected along with the sinus tract to avoid recurrence and remove all ramifications of PAS tract.