Surgical treatment of preauricular sinus-cyst-tract.
A preauricular sinus or cyst is a common congenital malformation that usually occurs at the anterior margin of the ascending limb of the helix of the external ear. They are inherited features and usually appear on one side, but may be bilateral in 70-80% of cases. It may be an inclusion dermoid resulting from epithelium trapped between
The developing auricular tubercles or it may be a remnant of the first branchial groove epithelium, which has failed to resorb.
Most preauricular sinuses are asymptomatic and remain untreated unless they become infected too often. Preauricular cysts are treated with surgery which, because of their close proximity to the facial nerve should be left to an experienced ENT surgeon.
Recurrence in preauricular sinus excision is due to incomplete excision of the sinus tract and presence of residual viable squamous epithelium. Recurrence can manifest in the form of persistence of sepsis, resurgence of swelling, repeated sinus discharge or recurrence of a preauricular mass.
Single stage excision under a general anesthesia is preferred.
Pre operative investigation
1. Audiogram to rule out any Conductive hearing loss.
2. CT Scan-Sinogram with contrast.
3. Renal ultrasound
Operation in a virgin case will not be difficult but the epithelial tracts can go any where.
Once infected and drained, the excision in toto will be extremely challenging and gives recurrence.
Magnification with an operating microscope enables precise dissection without any epithelial breach. Copious local infiltration with adrenaline facilitates a bloodless field for the surgeon, making dissection more easy and fruitful. Blunt metal probing (lachrymal probe) to delineate the sinus ramifications, should be gentle and meticulous to avoid the creation of new false passages. Injecting methylene blue should also be gentle to avoid leakage to false passages.
Bipolar diathermy ensures a clean bloodless field. Meticulous planning Preoperatively and peroperatively, helps minimize the scar.
Beware of the facial nerve in extensive dissection.