Nager syndrome is another autosomal dominant disorder characterized by patients with faces similar to individuals with Treacher Collins syndrome. These patients also have “bird-like” features and their mandibles are typically small and recessed with an obtuse angle. Their distinction lies in the fact that they have more severe ear deformities than patients with Treacher Collins. They also have characteristic upper and lower extremity defects. The genetic mutation associated with this deformity is currently unknown.
The treatment of the mandibular malformations in these patients varies based on the degree of underlying pathology. Patients with minimal deformity require either no treatment or a sliding genioplasty (chin augmentation), in order to normalize facial appearance. However, the majority of patients have more severe forms of micrognathia (small lower jaw) and require some form of bone grafting or orthognathic surgery to generate an adequate repair. Bone grafting of the mandible with costochondral rib grafts has traditionally been performed in the prepubescent years in order to augment mandibular projection. Definitive orthognathic surgery is typically delayed until facial skeletal maturity, with adult teeth erupted, in order to decrease the incidence of post-surgical skeletal relapse.
Patients with severe bilateral micrognathia can be treated at an early age via mandibular distraction osteogenesis. Distraction offers the advantage over traditional mandibular reconstructive approaches in that it can be done earlier and allows for over projection on the growing child’s skeleton to account for later growth. Probably the greatest advantage of mandibular distraction is its enlargement of the airway and often permits decannulation of a tracheostomy.
Patients with Treacher Collins syndrome and Nager syndrome frequently also require reconstructive surgery of the lower eyelid and ear. Ear reconstruction can begin at age 7-10 and are usually completed in 2 or 3 stages. The use of autogenous rib cartilage to carve and craft the new ear is recommended. This produces the most acceptable, long lasting result.
Prior to these reconstructions, all patients should receive a full evaluation by the team audiologist, otolaryngologist, and speech therapist. A full examination of the middle and inner ear structures should be performed in order to develop a plan for future ear reconstruction and to optimize both hearing and subsequent speech development. In many cases, a bone conducting hearing aid can be created which will solve the majority of the hearing problems. In those which it cannot, further treatment alternatives will be discussed and customized to meet each individuals needs.
Lower eyelid reconstruction can begin as early as age six. Simple procedures such as medial or lateral canthopexies can be used to correct abnormal lid position in many cases. However, in patients with severe underlying cheekbone deficiencies, bone grafting to the cheek is required to give the lid a good foundation on which to rest, prior to moving any soft tissue. Without this support, the lids themselves would sink back down to their pre-surgical position. Lastly, when virtually no lower lid is present, a vascularized transfer of upper lid skin and muscle to the lower lid may be indicated.