1
Introduction
The genioglossus muscle originates from the genial tubercle, inserts posteriorly at the tip of the tongue and the dorsum of the tongue, and into the body of the hyoid bone ( Fig. 52.1 ). The fibers retract the tip of the tongue, depress the dorsum of the tongue, and move the hyoid in an anterosuperior direction. The muscle receives the majority of its blood supply from the bilateral lingual arteries and is innervated by cranial nerve XII. It serves as a dilator of the pharynx and is thought to play a major role in nocturnal airway obstruction. Genioglossus advancement surgery (GA) places tension on the tongue musculature to limit posterior displacement during sleep. This chapter serves to describe GA; however, the procedure has largely fallen out of favor and is only performed in specific circumstances. Several less invasive options are currently available with potentially greater effectiveness.
2
Indications/Contraindications
Patient selection for GA includes adult patients with a Fujita type II (retropalatal and retrolingual) or type III (retrolingual) abnormality with evidence of moderate to severe obstructive sleep apnea (OSA) demonstrated by polysomnography and failure of conservative therapies (such as weight loss, dental appliances, or positive airway pressure) to resolve symptoms. Reasons to exclude potential candidates include poor cardiopulmonary health, inability to undergo general anesthesia, or Fujita type I abnormalities (retropalatal).
3
Procedure Details
To locate the genial tubercle and avoid dental injury, a Panorex or a computerized tomography scan may be obtained preoperatively. The procedure is performed under general anesthesia with endotracheal or nasotracheal intubation. A local anesthetic injection (10 mL of 2% lidocaine with epinephrine) is administered at the anterior gingivobuccal sulcus. The procedure begins with a mucosal incision approximately 10 mm below the mucogingival junction. A subperiosteal dissection is performed to expose the mandibular symphysis. The mental foramen, containing the inferior alveolar nerves, are lateral to the surgical site and do not need to be identified. Several osteotomy designs have been used to advance the genioglossus muscle, including standard genioplasty, mortised genioplasty, and inferior sagittal “box” osteotomies. Vertical osteotomies are made medial to the canine tooth to avoid tooth root injury with an oscillating microsaw. The inferior horizontal bone cut should be designed to preserve approximately 10 mm of the inferior border of the mandible to reduce the risk of a pathologic fracture. Before completing the osteotomy, a titanium screw is placed in the outer cortex manipulate the bone flap. At the completion of the osteotomy, the bone flap is released from the surrounding bone, advanced, and rotated 60 to 90 degrees to prevent retraction back into the floor of the mouth. The bone is rigidly fixed with a lag screw, and the outer cortex and marrow of the repositioned mandibular segment are removed using a rough bur ( Fig. 52.2 ). It is important to irrigate the wound with copious irrigation to eliminate bone dust. Avoid bone wax for hemostasis, as it has been associated with extrusion.
