First Branchial Cleft Anomalies: Managing Various Cervico-Facial Anomalies and Otologic Malformations at a large Canadian Referral Centre

Methods: We conducted a retrospective chart review of all patients consecutively referred to the senior authors at a tertiary-care Pediatric Otolaryngology clinic for fi rst branchial cleft anomalies over a 14-year period. Patients underwent computerized tomography scan with contrast, otoscopy plus tympanic microsurgery, when indicated (29%), methylene blue mapping of the cutaneous opening, when present (57%), intra-operative facial nerve monitoring, and anterograde or retrograde facial nerve dissection, when necessary (86%).


Background
The branchial arches appear as 4 paired arches of tissue at 4 weeks gestational age. The branchial clefts are composed of ectoderm, the pouches are formed of endoderm, while the mesenchyme of the arch will form an artery, nerve, cartilaginous bar, and muscle. With regards to the fi rst branchial arch, the specifi c structures that develop are the maxillary Abstract Background: Branchial cleft anomalies account for approximately 17% of pediatric neck masses and 30% of all congenital neck lesions; of these, less than 1% involve the fi rst branchial cleft. We report several novel otologic malformations encountered in children with fi rst branchial cleft anomalies; as well as our surgical techniques and outcomes.

Methods:
We conducted a retrospective chart review of all patients consecutively referred to the senior authors at a tertiary-care Pediatric Otolaryngology clinic for fi rst branchial cleft anomalies over a 14-year period. Patients underwent computerized tomography scan with contrast, otoscopy plus tympanic microsurgery, when indicated (29%), methylene blue mapping of the cutaneous opening, when present (57%), intra-operative facial nerve monitoring, and anterograde or retrograde facial nerve dissection, when necessary (86%).
Results: Seven patients presented with fi rst branchial cleft anomalies, at an average age of 3.9 years. Five of seven patients (71%) presented with cervico-facial infection. Four of the anomalies were sinuses, 2 were cysts and 1 was a fi stula. Two patients had a classic myringeal web. One patient had a large posterior intratympanic keratoma, partial myringeal duplication, and wax-pocket; while another patient had external auditory canal triplication and a small intratympanic keratoma. In 6 cases (86%) there was distortion of anatomical landmarks and retrograde facial nerve dissection was therefore employed. In one patient, no branches of the facial nerve were identifi ed during excision. In two patients, re-anastomosis of a small distal branch of the facial nerve was performed. Five patients (71%) experienced transient facial nerve weakness. However, with a mean length of follow-up of 7.5 years, no permanent facial nerve weakness, recurrence, or hearing loss has been identifi ed.

Conclusions:
We present several novel otologic fi rst branchial cleft fi ndings, as well as the experience of a two-surgeon team using methylene blue mapping plus monitored and primarily retrograde facial nerve dissection. This approach appears relatively safe and effective in children with these highly variable anomalies.
artery, trigeminal nerve, muscles of mastication, mylohyoid, anterior belly of digastric muscle, tensor tympani, tensor veli palatini, maleus, incus, and a portion of the mandible. The fi rst branchial cleft forms the external auditory canal and the fi rst branchial pouch forms the Eustachian tube, middle ear cavity, and mastoid air cells. Formation of these structures occurs early and rapidly in gestation; as such this process is predisposed to error and resultant congenital anomalies. all branchial cleft malformations; however, making them exceedingly rare [1]. They tend to present as a cyst, sinus, or fi stula occurring in a region known as Pochet's triangle, which is bounded by the external auditory canal superiorly, the mental region anteriorly, and the hyoid bone inferiorly [2]. Symptoms include drainage from a pit-like depression in this region, submandibular adenitis, a parotid mass, or otorrhea. 10% of lesions are also associated with an asymptomatic membranous attachment between the tympanic membrane and fl oor of the external auditory canal [2,3]. These lesions are not to be confused with pre-auricular sinuses, which by defi nition are superfi cial to the fi rst branchial cleft (and were excluded from this study).
Historically, FBCA have been divided into type I and type II lesions by means of a histopathological classifi cation system [1]. Type I lesions are made up of ectoderm exclusively, while type II lesions contain ectoderm and mesoderm [1]. Several authors have reported on the relationship of these types of lesions to the facial nerve, with type I tending to be superfi cial and type II tending to be deep to the nerve [1,3,4]. It has been recognized however that, in many cases, these anomalies do not abide to these classifi cations nor anatomical relationships [4].
Our objective was to describe our surgical approach and outcomes with these rare and challenging congenital lesions as well as report on several novel associated otologic malformations encountered in our clinical experience. We have also reviewed the relevant literature.

Patients
After obtaining IRB approval, the charts of all patients consecutively referred to a two-surgeon team over a 14-year period for FBCA were retrospectively reviewed. 7 patients were identifi ed; 6 female and 1 male. The mean age at presentation was 3.9 years. 5 patients presented with active infection. No associated craniofacial anomalies or syndromes were identifi ed and there was no pre-operative facial nerve dysfunction. Six patients were imaged with computed tomography scan (some after initial ultrasound) and one patient had an MRI due to parent refusal. Figures 1,2 Anesthetic induction was performed by the anesthetist using total intravenous anesthesia, which is the standard of practice at our center, using only short acting paralytic agents. The ears were then examined under the microscope.
Any cerumen or granulation tissue was carefully debrided; intra-tympanic keratomas and/or wax pockets were carefully  unroofed. Over the course of this series, when the ear canal caliber allowed, an endoscopic approach to the tympanic exam and microsurgery became more commonly employed. High defi nition endoscopic images were taken of notable fi ndings, using a 0 degree endoscope and 3 chip camera. When an isolated classic myringeal web was discovered (14% of cases), no further surgical intervention was performed.
A modifi ed Blair incision was marked, with the cervical limb lying in a natural skin crease, then injected with Marcaine or Xylocaine with epinephrine. When a facial cutaneous opening was present (and no evidence of G6PD defi ciency anemia) methylene blue was instilled, using a 24 or 26 gauge plastic angiocatheter, as previously described [5]. If purulent fl uid was milked from the tract just prior instillation of methylene blue, then this was sent for culture and sensitivity. The facial nerve monitor was then applied and the patient was prepared and draped with the ipsilateral hemiface exposed. Superfi cial skin fl aps were raised taking great care to identify and avoid the branches of the facial nerve. When possible, the main trunk of the facial nerve was identifi ed at the depth of the posterior belly of the digastric muscle by blunt dissection and followed forward into the parotid gland prior to dissecting the infl ammatory mass. When there is distortion of landmarks as a result of the lesion, a small, distal branch of the facial nerve was identifi ed and traced back in retrograde fashion to identify other branches according to the method described by Anjum et al [6]. The mass (and its stalk) was then dissected bluntly using Jacobson forceps and facial nerve probe guidance. Division of subcutaneous tissue was performed in layers using microbipolar cautery, but only a facial nerve stimulator was used to verify safety. The entire cyst and epithelial component of the fi stula tract was removed; but in certain cases, in order to minimize the risk of injury to the facial nerve, the cartilaginous sleeve component of the lesion was left in situ. Complete hemostasis was achieved with epinephrine soaked peanuts and bipolar cautery.
Before closure, all isolated branches of the facial nerve were stimulated to verify functionality. The site was then irrigated with a saline and bacitracin solution. The superfi cial parotid fascia was closed using 4-0 PDS or Vicryl in order to prevent Grey's syndrome. The skin was then closed in layers with 4-0 PDS or Vicryl for the dermis and a 6-0 fast-gut running stitch for the epidermis. A Penrose drain was typically left in place at the inferior aspect of the wound under a light pressure dressing and removed the next morning.

Operative approach
In 6 cases (86%) the lesion caused signifi cant distortion of anatomical landmarks, thereby necessitating retrograde facial nerve dissection. 3 lesions were superfi cial to the facial nerve, 2 were deep, 1 was partly superfi cial and partly deep to the facial nerve; and in 1 case the nerve was not visualized.

Surgical outcomes
The epithelial portion of the lesion was completely resected in all cases. In 2 cases a distal branch of the facial nerve was transected; in 1 of these cases this was planned in order to deliver the mass. In these cases, we performed primary re-anastamosis of the nerve, without tension, under the microscope, using simple interrupted 8-0 Prolene.

Discussion
Several other case series have been reported in the scientifi c literature (Tables 1,2). In 1996, Agaton and colleagues described their series of 35 primarily female patients with a mean age of 23 years [7]. All lesions were excised using a wide transverse cervicotomy incision. At 2 years clinical follow up, a 4% recurrence rate was seen with 0% facial nerve paralysis.   [4,9,10]. In the 105 patients treated by superfi cial parotidectomy in these studies, recurrence rates ranged from 0-10% and facial nerve paralysis complicated 0-5.6% of cases (Table 2).
In 2012, 2 reports were published detailing the results of a unique surgical approach controlling the sinus from within the cyst lumen under the operating microscope and employing retrograde facial nerve dissection when needed. No blue dye mapping or facial nerve monitoring was employed [11,12]. The 23 patients treated in this fashion experienced no facial nerve paralysis or lesion recurrence [11,12].