A preauricular pit is a benign congenital malformation of the preauricular soft tissues that may be accompanied by a sinus tract or subcutaneous cyst. In a minority of cases, the presence of a preauricular anomaly may be associated with a multiple congenital anomaly syndrome. Most preauricular anomalies are asymptomatic, however approximately 25% of patients will experience an infection at some point after which excision of the pit and associated cyst/sinus tract is indicated. Excision is best performed under general anesthesia during a period of quiescence following infection. The supra-auricular approach offers a lower recurrence rate that simple cyst excision and is the preferred technique. Dissection along the helical cartilage ensures that the sinus tract will not be violated, and a cuff of cartilage can be safely taken along with the soft tissues if needed. Skin can be closed primarily and Dermabond used to create a water-tight seal. Postoperatively, Tylenol and Motrin are sufficient for pain control and antibiotics are not needed. Risks associated with the procedure are low and consist primarily of minor wound complications.
15 Preauricular Anomalies
The preauricular pit is a benign congenital malformation of the preauricular soft tissues first described by Heusinger in 1864. 1 – 3 It is most frequently noted during routine physical exam and appears as a small pit close to the anterior margin of the ascending portion of the helix (▶ Fig. 15.1). The sinus pit may represent the full extent of the deformity or the beginning of a tortuous sinus tract, an adjacent subcutaneous cyst may also be present. 4 , 5 The most accepted theory is that the development of a preauricular sinus is due to incomplete or defective fusion of the six hillocks of His during the development of the external ear during the sixth week of gestation. 1 – 6 The majority are asymptomatic; however, they can become infected and present with pain, swelling, erythema, discharge, or abscess formation in approximately 25% of patients. 2 Surgical excision is indicated after an episode of symptomatic infection and should be performed during a period of quiescence. The incidence of preauricular sinuses varies among populations and is estimated to be 0.1% to 0.9% among Western populations, 4% to 6% in Asians and up to 10% in some regions of Africa. 5 Greater than 50% of cases are unilateral and sporadic. Bilateral cases are more likely to be inherited by incomplete autosomal dominance with reduced penetrance. 1
The initial surgical technique used for excision was the simple sinectomy, in which an elliptical incision is made around the pit and the sinus tract is followed and excised. Due to the variation in sinus tracts and small ramifications that may be present, this technique resulted in a high recurrence rate likely secondary to incomplete excision. In 1990 Prasad described the supra-auricular approach in which the incision is extended postauricularly and all subcutaneous tissues between the temporalis fascia and cartilage of the helix are removed en bloc without dissection of the sinus tract. 7 He reported a recurrence rate of 42% with simple sinectomy and only 5% with the supra-auricular approach. Further studies have shown similar results; Lam et al reported in 2001 a recurrence rate of 32% with simple sinectomy versus 3.7% with the supra-auricular approach. 6 A meta-analysis by El-Anwar looking at all published series of preauricular cases since 2001 showed a recurrence rate of 8.1% with simple sinectomy and 1.2% with supra-auricular approach, a smaller yet statistically significant difference. 3
15.2 Preoperative Evaluation and Anesthesia
Preauricular sinus pits are most often an isolated congenital malformation requiring no further workup. However, like many other malformations related to the ear, the incidence of renal anomalies in patients with preauricular sinus pits is higher than that in the general population. 1 Guidelines developed by Wang et al in 2001 state that a patient with isolated preauricular pit(s) accompanied by any one of the following should undergo renal ultrasound to aid in the diagnosis of a multiple congenital anomaly syndrome: maternal history of gestational diabetes, family history of deafness, branchial cleft sinus or cyst, another malformation or dysmorphic feature of the face, limbs, heart, or gastrointestinal system. 8 In all other cases, renal ultrasound is not recommended.
Surgery is indicated only in cases of symptomatic infection and should be performed after complete resolution of infection or drainage from the sinus. Preoperative clearance should be obtained from a pediatrician.
Excision can be performed under local or general anesthesia, although superior results with lower recurrence rates have been shown when general anesthesia was used. 1 , 2 , 5 This is likely due to patient intolerance and potential distortion of tissues from infiltration of local anesthesia around the areas of dissection. 1 We recommend the procedure be performed under general anesthesia in all cases unless contraindicated by patient factors.