Preauricular sinus is an embryological aberration involving the developing pinna.
Theories of preauricular sinus formation:
Embryological fusion theory:
This commonly accepted theory suggests the preauricular sinus develops due to fusion defects involving the 6 hillocks which develop into the future pinna.
Ectodermal infolding theory:
This theory attributes preauricular sinus to ectodermal infolding defects that occur during development of pinna. Ofcourse this theory has no takers. This theory assumes that preauricular sinus forms part of other branchogenic malformations.
Various syndromes associated with preauricular sinus formation are:
- Branchio oto renal syndrome
- Branchio oto urethral sundrome
- Branchio otic syndrome
- Branchio oto costal syndrome
- Cat eye syndrome
- Trisomy 22
Surgical options for management of preauricular sinus:
Jensma technique is commonly preferred surgical treatment modality. In this technique the tract is identified after injecting dye (GV paint) via the punctum. A circular incision is made to encircle the opening of the preauricular sinus and the whole sinus is followed using dye diffusion as a guide. Major problem of this technique is that the recurrence rate is very high. It is not a suitable approach in patients with infected preauricular sinus.
Common causes of recurrence:
- Incomplete removal of lesion
- Failure to use magnification during surgery
- Skill of the surgeon
Supra auricular approach:
This is a more radical approach. Major benefit of this procedure is it low recurrence rate. This surgery is performed using a comet incision. The head of the comet incision is around the external opening of the sinus. The tail of the comet is fashioned in such a way that it passes anterior to the helix, superior to the pinna over the temporal area. The temporalis fascia is the medial limit of the dissection. All the tissue superficial to the temporalis fascia should be removed. It is also important to remove a cuff of cartilage around the outer opening of the preauricular sinus.
Picture showing preauricular sinus
Comet incision shown
Removal of sinus along with a bit of helical cartilage
View of wound closure
You can view the procedure below;