Key points

Genioglossus advancement for treatment of obstructive sleep apnea

Surgical intervention for obstructive sleep apnea (OSA) is a complex topic. The discussion involves intricate procedures targeting specific areas of the upper airway. Because of the wide variety of physiologic and anatomic causes of this disorder it is important to tailor the treatment to offer the patient the best possible outcome. Fujita used a classification system to better describe the level of collapse seen in patients with OSA. Type I describes abnormalities of the upper oropharyngeal airway, including the palate, uvula, and tonsils. Type II consist of upper oropharyngeal and hypopharyngeal airway pathology, and type III involves only the hypopharyngeal airway (lingual tonsils, tongue base, supraglottis, and hypopharynx). The importance of targeting the appropriate level of airway collapse is exemplified by Sher and colleagues, who reported only a 5% success in patients with retrolingual (type II and III) collapse who undergo a uvulopalatopharyngoplasty (UPPP) alone. This article discusses a specific procedure designed to treat those patients with type II and type III obstruction.

Genioglossus advancement (GA) was first described by Riley and coworkers 1984. The procedure involved the advancement of the genial tubercle/genioglossus muscle for the treatment of hypopharyngeal obstruction in OSA. The rationale of this technique was to stabilize the hypopharyngeal airway by moving forward the genioglossus complex providing tension on the base of the tongue and, thereby, expanding the airway in the anteroposterior dimension. Over the last 30 years, there have been variations proposed to the original technique to improve outcomes and limit complications. Despite these variations, the principle of the procedure remains the same, and results have shown significant resolution of OSA symptoms and improvement in polysomnography data for those exhibiting type II (when combined with oropharyngeal procedures) and type III obstruction.

Understanding of GA begins at the anatomic level. The genioglossus muscle is an extrinsic muscle of the tongue. It originates from the superior mental spine or genial tubercles, and fans posterior to insert at the tip of the tongue, dorsum of the tongue, and into the body of the hyoid bone. This allows it to serve as a dilator of the pharynx at the level of the tongue base. The muscle is innervated by cranial nerve XII and receives its major vascular supply from the lingual arteries.

The anatomic dimensions of the musculature and its relationship to the anterior mandible are clinically significant to the GA. Studies have shown the width of the genial tubercle attachments to the inner table of the mandible can vary from 3 mm to 15 mm. In the context of GA, understanding the proximity of the tubercle attachment to the tooth roots is also crucial. The superior border of the genial tubercle has been described, on average, just 6.45 mm inferior to the apex of the central incisor with 35% of specimens having less than 5 mm clearance from the incisor roots. Understanding the anatomic relationship of the muscle to the anterior mandible and tooth roots helps the surgeon design an osteotomy for advancement of the tongue musculature. For maximal results, the dimensions of the osteotomy must be large enough to allow for the advancement of the greatest amount of genioglossus muscle without sacrificing the tooth roots.

The inferior border advancement genioplasty was the initial GA procedure described by Riley and colleagues. The inferior border of the mandible is sectioned and advanced anteriorly with the dentoalveolar process left intact. The osteotomized segment must extend superiorly enough to incorporate the genioglossus attachment but not involve the tooth roots of the lower incisors or canines. Concerns regarding mandibular fracture led to minor innovations in the procedure by leaving an intact inferior mandible and advancing the genial tubercles anteriorly through a rectangular window osteotomy, as described by Li and colleagues ( Figs. 1 and 2 ).

Anterior view of the genioglossus advancement using the rectangular window technique.

Lateral view of the rectangular window technique showing the genioglossus attachments extending to the hyoid.

Variations of this procedure include different types of osteotomies and slight alteration in transposition of the bone segment. The 90° rotation of the bony window segment involved in the previously stated procedure drew criticism for its risk of stripping the genial tubercle form the lingual cortex. An alternative technique involves a similarly placed osteotomy with laterally slanting vertical cuts. The labial cortex and medullary bone are removed and the remaining lingual cortical bone (with intact genial tubercles) is then brought anteriorly without rotation and secured with a prebent plate.

Garcia and colleagues propose a slight alternative to the rectangular window by introducing a longitudinal groove on the floor of the window after the bony block is freed. The segment is then brought anterior and displaced inferiorly to overlap intact mandible in order for the genial tubercle to rest in the created groove. The advantages with this technique are greater anterior advancement of the genioglossus with inferior displacement and lack of segment rotation (avoiding possible stripping). A circular trephination approach is also described, designed to reduce risk of lateral incisor tooth root injury while still maintaining optimal genial tubercle capture.

In the patient with micrognathic OSA, further chin augmentation with mandibular advancement may be desired. In these instances a genioplasty combined with GA may be more appropriate. This is exemplified by Riley’s original inferior border advancement genioplasty. One may also consider a mortised genioplasty. The latter incorporates anterior advancement of the genioglossus, mylohyoid, digastric, and geniohyoid. This is accomplished in a similar method to the inferior mandibular osteotomy with the exception of the lateral cuts extending through the inferior border of the mandible and well lateral to the mental foramen. Another option is a two-piece GA, described as a horizontal osteotomy mobilizing the inferior mandible segment in addition to the anterior rectangular window GA. This technique allows the direct visualization and palpation of the genioglossus after the inferior border of the mandible is reflected inferiorly. After the anterior rectangle block is advanced, the inferior border is reconstituted to improve the stability of the mandible and can be advanced antereriorly. The GA can also be combined with hyoid elevation to increase the degree of hypopharyngeal airway expansion. The hyoid is exposed and suspended with bilateral suture through the newly created bony window in the mandible.

The combination of GA with other hypopharyngeal or oropharyngeal procedures is often necessary to fully address OSA, making direct comparisons between isolated procedures difficult. Although there is a paucity of level one and level two studies on the outcomes of GA for OSA, there have been numerous case series and retrospective studies with similarly positive results. Success, often described as apnea-hypopnea index (AHI) less than 20 and a 50% reduction of AHI, in the literature ranges widely between 40% and 70%.

Riley and colleagues described a 60% success rate out of 223 patients who received an UPPP and GA with hyoid suspension for type II upper airway obstruction. The study also showed 67% success in those who received only GA with hyoid suspension for type III obstruction, although there were only six patients in this group. “Success” in this study was defined as subjective and objective reports indicating significant improvement equivalent to that seen in patients monitored with nasal continuous positive airway pressure, or if the postoperative respiratory disturbance index (RDI) was less than 20 with at least a 50% reduction over the preoperative study. A review of the literature by Kezirian and Goldberg revealed four case series totaling 91 cases and a success rate of 62%. Three of the four series showed a 67% to 78% success rate.

A prospective randomized study by Thomas and colleagues comparing GA with tongue base suspension demonstrated a reduction in Epworth Sleepiness Scale (ESS) scores in the GA group (eight patients) from a mean of 13.3 to 5.4. Airway collapse for five of eight patients measured on Müller maneuver improved by a mean of 75% at the base of the tongue. Kuscu and colleagues recently studied isolated GA results for patients and noted a 53% success rate; there was a significantly higher success rate for those with mild or moderate OSA compared with the severe cases, which is in line with other studies.

Intraoperative complications of the various GA procedures include stripping of the genial tubercle from the lingual cortex of the bone segment, osseous segment necrosis, fracture of the labial cortex, fracture of the mandible, violation of tooth roots, and neurosensory changes. The incidence of these complications seems to be low, but no systematic study has thoroughly evaluated this. The previous surgical technique discussion addresses the various alterations surgeons have proposed to decrease complication rates. Later complications include hematoma, seroma, infection, and mandible fracture; these too are rarely encountered.

There remains a critical role for hypopharyngeal procedures in the surgical treatment of OSA. GA is among the procedures designed for this subgroup of patients with OSA with collapse of the lower pharyngeal airway and shows consistently positive results. The surgical technique has evolved over the last 30 years and continues to be modified to increase its safety and efficacy. With careful patient selection, it remains a viable option in the surgical management of OSA.

Genioglossus advancement for treatment of obstructive sleep apnea

Surgical intervention for obstructive sleep apnea (OSA) is a complex topic. The discussion involves intricate procedures targeting specific areas of the upper airway. Because of the wide variety of physiologic and anatomic causes of this disorder it is important to tailor the treatment to offer the patient the best possible outcome. Fujita used a classification system to better describe the level of collapse seen in patients with OSA. Type I describes abnormalities of the upper oropharyngeal airway, including the palate, uvula, and tonsils. Type II consist of upper oropharyngeal and hypopharyngeal airway pathology, and type III involves only the hypopharyngeal airway (lingual tonsils, tongue base, supraglottis, and hypopharynx). The importance of targeting the appropriate level of airway collapse is exemplified by Sher and colleagues, who reported only a 5% success in patients with retrolingual (type II and III) collapse who undergo a uvulopalatopharyngoplasty (UPPP) alone. This article discusses a specific procedure designed to treat those patients with type II and type III obstruction.

Genioglossus advancement (GA) was first described by Riley and coworkers 1984. The procedure involved the advancement of the genial tubercle/genioglossus muscle for the treatment of hypopharyngeal obstruction in OSA. The rationale of this technique was to stabilize the hypopharyngeal airway by moving forward the genioglossus complex providing tension on the base of the tongue and, thereby, expanding the airway in the anteroposterior dimension. Over the last 30 years, there have been variations proposed to the original technique to improve outcomes and limit complications. Despite these variations, the principle of the procedure remains the same, and results have shown significant resolution of OSA symptoms and improvement in polysomnography data for those exhibiting type II (when combined with oropharyngeal procedures) and type III obstruction.

Understanding of GA begins at the anatomic level. The genioglossus muscle is an extrinsic muscle of the tongue. It originates from the superior mental spine or genial tubercles, and fans posterior to insert at the tip of the tongue, dorsum of the tongue, and into the body of the hyoid bone. This allows it to serve as a dilator of the pharynx at the level of the tongue base. The muscle is innervated by cranial nerve XII and receives its major vascular supply from the lingual arteries.

The anatomic dimensions of the musculature and its relationship to the anterior mandible are clinically significant to the GA. Studies have shown the width of the genial tubercle attachments to the inner table of the mandible can vary from 3 mm to 15 mm. In the context of GA, understanding the proximity of the tubercle attachment to the tooth roots is also crucial. The superior border of the genial tubercle has been described, on average, just 6.45 mm inferior to the apex of the central incisor with 35% of specimens having less than 5 mm clearance from the incisor roots. Understanding the anatomic relationship of the muscle to the anterior mandible and tooth roots helps the surgeon design an osteotomy for advancement of the tongue musculature. For maximal results, the dimensions of the osteotomy must be large enough to allow for the advancement of the greatest amount of genioglossus muscle without sacrificing the tooth roots.

The inferior border advancement genioplasty was the initial GA procedure described by Riley and colleagues. The inferior border of the mandible is sectioned and advanced anteriorly with the dentoalveolar process left intact. The osteotomized segment must extend superiorly enough to incorporate the genioglossus attachment but not involve the tooth roots of the lower incisors or canines. Concerns regarding mandibular fracture led to minor innovations in the procedure by leaving an intact inferior mandible and advancing the genial tubercles anteriorly through a rectangular window osteotomy, as described by Li and colleagues ( Figs. 1 and 2 ).

Anterior view of the genioglossus advancement using the rectangular window technique.

Lateral view of the rectangular window technique showing the genioglossus attachments extending to the hyoid.

Variations of this procedure include different types of osteotomies and slight alteration in transposition of the bone segment. The 90° rotation of the bony window segment involved in the previously stated procedure drew criticism for its risk of stripping the genial tubercle form the lingual cortex. An alternative technique involves a similarly placed osteotomy with laterally slanting vertical cuts. The labial cortex and medullary bone are removed and the remaining lingual cortical bone (with intact genial tubercles) is then brought anteriorly without rotation and secured with a prebent plate.

Garcia and colleagues propose a slight alternative to the rectangular window by introducing a longitudinal groove on the floor of the window after the bony block is freed. The segment is then brought anterior and displaced inferiorly to overlap intact mandible in order for the genial tubercle to rest in the created groove. The advantages with this technique are greater anterior advancement of the genioglossus with inferior displacement and lack of segment rotation (avoiding possible stripping). A circular trephination approach is also described, designed to reduce risk of lateral incisor tooth root injury while still maintaining optimal genial tubercle capture.

In the patient with micrognathic OSA, further chin augmentation with mandibular advancement may be desired. In these instances a genioplasty combined with GA may be more appropriate. This is exemplified by Riley’s original inferior border advancement genioplasty. One may also consider a mortised genioplasty. The latter incorporates anterior advancement of the genioglossus, mylohyoid, digastric, and geniohyoid. This is accomplished in a similar method to the inferior mandibular osteotomy with the exception of the lateral cuts extending through the inferior border of the mandible and well lateral to the mental foramen. Another option is a two-piece GA, described as a horizontal osteotomy mobilizing the inferior mandible segment in addition to the anterior rectangular window GA. This technique allows the direct visualization and palpation of the genioglossus after the inferior border of the mandible is reflected inferiorly. After the anterior rectangle block is advanced, the inferior border is reconstituted to improve the stability of the mandible and can be advanced antereriorly. The GA can also be combined with hyoid elevation to increase the degree of hypopharyngeal airway expansion. The hyoid is exposed and suspended with bilateral suture through the newly created bony window in the mandible.

The combination of GA with other hypopharyngeal or oropharyngeal procedures is often necessary to fully address OSA, making direct comparisons between isolated procedures difficult. Although there is a paucity of level one and level two studies on the outcomes of GA for OSA, there have been numerous case series and retrospective studies with similarly positive results. Success, often described as apnea-hypopnea index (AHI) less than 20 and a 50% reduction of AHI, in the literature ranges widely between 40% and 70%.

Riley and colleagues described a 60% success rate out of 223 patients who received an UPPP and GA with hyoid suspension for type II upper airway obstruction. The study also showed 67% success in those who received only GA with hyoid suspension for type III obstruction, although there were only six patients in this group. “Success” in this study was defined as subjective and objective reports indicating significant improvement equivalent to that seen in patients monitored with nasal continuous positive airway pressure, or if the postoperative respiratory disturbance index (RDI) was less than 20 with at least a 50% reduction over the preoperative study. A review of the literature by Kezirian and Goldberg revealed four case series totaling 91 cases and a success rate of 62%. Three of the four series showed a 67% to 78% success rate.

A prospective randomized study by Thomas and colleagues comparing GA with tongue base suspension demonstrated a reduction in Epworth Sleepiness Scale (ESS) scores in the GA group (eight patients) from a mean of 13.3 to 5.4. Airway collapse for five of eight patients measured on Müller maneuver improved by a mean of 75% at the base of the tongue. Kuscu and colleagues recently studied isolated GA results for patients and noted a 53% success rate; there was a significantly higher success rate for those with mild or moderate OSA compared with the severe cases, which is in line with other studies.

Intraoperative complications of the various GA procedures include stripping of the genial tubercle from the lingual cortex of the bone segment, osseous segment necrosis, fracture of the labial cortex, fracture of the mandible, violation of tooth roots, and neurosensory changes. The incidence of these complications seems to be low, but no systematic study has thoroughly evaluated this. The previous surgical technique discussion addresses the various alterations surgeons have proposed to decrease complication rates. Later complications include hematoma, seroma, infection, and mandible fracture; these too are rarely encountered.

There remains a critical role for hypopharyngeal procedures in the surgical treatment of OSA. GA is among the procedures designed for this subgroup of patients with OSA with collapse of the lower pharyngeal airway and shows consistently positive results. The surgical technique has evolved over the last 30 years and continues to be modified to increase its safety and efficacy. With careful patient selection, it remains a viable option in the surgical management of OSA.