Do you want to learn more genial tubercle advancement (genioglossus advancement) surgery?

We understand that helpful information can be hard to find.

This post provides illustrations that show how genial tubercle advancements are performed, with several illustrations.

The post was written by an Ear, Nose, and Throat (ENT)/sleep surgeon.

Genial tubercle advancement with a side view with a screw holding the bone segment into position and a green arrow pointing to the cut bone. CamachoMD.com
Genial tubercle advancement viewed from the side. Note there is a screw holding the bone segment into position and a green arrow points to the cut bone.

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Summary for genial tubercle advancement:

Genial tubercle advancement is when a window is made in the middle part of the chin and is moved forward.

The procedure is usually performed for obstructive sleep apnea.

It can help improve obstructive sleep apnea is because the tongue (the genioglossus muscle specifically) has attachments to the chin at a location known as the genial tubercle.

What is a genial tubercle advancement?

Genial tubercle advancement, also known as a genioglossus advancement, is a procedure that moves the genial tubercle and genioglossus muscle forward.

Genial tubercle advancement can be performed alone, or in combination with moving the lower chin forward (sliding genioplasty), or in combination with jaw surgery (maxillomandibular advancement).

Since the tongue is attached to the genial tubercle, the tongue also moves forward when the genial tubercle is moved forward.

What is the genial tubercle?

The genial tubercle is a bump inside the lower jaw (mandible), where the genioglossus muscle attaches.[1]

Genial tubercle advancement viewed from the side. Note the bone is pulled through the bone of the chin. The green arrow points to the advanced bone. CamachoMD.com
Genial tubercle advancement viewed from the side. Note the bone is pulled through the bone of the chin. The green arrow points to the advanced bone.

The optimal genial tubercle advancement surgery incorporates the genioglossus muscle attachment such that the muscle moves forward and contains enough of the genial tubercle for a bony cut (osteotomy).[2]

How is a genial tubercle advancement performed step by step?

There are three main ways to perform the procedure:[3]

  • A circular spinning round saw (known as the genial bone advancement trephine (GBAT) system) can be used,[4]
  • A rectangular window can be made in the central part of the mandible (classic genioglossus advancement), or
  • The genioglossus can be moved forward with the lower part of the mandible in a combined genial tubercle advancement – sliding genioplasty.

First, the round circular pattern: the bone of the front part of the mandible is exposed and a round saw that spins is used to cut into the bone.

Second, the classic genioglossus advancement: the bone of the front part of the mandible is exposed and a rectangular pattern is made below the tooth roots, but above the lower border of the mandible, usually about 1 cm x 2 cm in size.

Bone window (osteotomy) for genial tubercle advancement. The green arrow points to the window that has been cut. The bone has been rotated and has been secured to the chin using a blue screw. CamachoMD.com
Bone window (osteotomy) for genial tubercle advancement. The green arrow points to the window that has been cut. The bone has been rotated and has been secured to the chin using a blue screw.

Third, the combination with a sliding genioplasty: the bone of the front part of the mandible is exposed and instead of making a rectangular shape, the bone is cut so that it incorporates the mandible itself. So, in essence, the chin is moved forward as a unit with the genial tubercle.

Genial tubercle advancement can be performed with or without a hyoid suspension, and with or without a maxillomandibular advancement.[5]

What are the steps for the classic genial tubercle advancement?

Patients need to have an empty stomach before surgery, so it is important that they eat nothing after midnight.

Patients arrive at the hospital or surgical center at the instructed time.

Once patients make it to the preoperative holding area, the surgeon, the anesthesia provider and the operating room nurse will meet with them to review the procedure(s).

An intravenous (IV) catheter is placed at some point before patients go to the operating room.

Patients are then taken to the operating room.

The anesthesia provider then puts them to sleep using medications and a tube is placed into the airway so that the patient can breathe (ventilate) throughout the surgery.

The surgeon then makes a cut in the patient’s lower lip, on the inside. Bleeding is stopped by using electrocautery (electricity and heat at the tip of an instrument).

The bone of the mandible is exposed and the site to be cut is exposed.

The x-rays are reviewed.

The surgeon then uses either a measuring technique in the operating room or technique with prefabricated templates.

Calipers (or a ruler) are used to measure the distance from the lower border of the mandible and from the top of the mandible so that the location is precisely placed, usually measuring 1 cm x 2 cm (although the actual size may vary).

In some cases, the surgeon works with a company to help design a template that can be placed onto the bone during the surgery and traced out, in a process called virtual surgical planning.

A saw is then used to cut through the bone of the mandible, usually a rectangular shape. The bleeding is stopped (cauterized), and sometimes bone wax is placed at the bleeding edge to help slow down or stop the bleeding.

Genial tubercle advancement bone window created in the chin. CamachoMD.com
Genial tubercle advancement bone window created in the chin.

The bone is then pulled forward and the mid and outer parts of the bone (cancellous bone and outer cortex of the mandible) is shaved or cut off.

The bone is turned 45 to 90 degrees.

The bone is then secured to the mandible using a screw or a plate with multiple screws.

Bone window (osteotomy) has been cut and the bone was rotated as part of the genial tubercle advancement. The bone was then secured to the chin using a screw. CamachoMD.com
Bone window (osteotomy) has been cut and the bone was rotated as part of the genial tubercle advancement. The bone was then secured to the chin using a screw.
Genial tubercle advancement viewed from the side. CamachoMD.com
Genial tubercle advancement viewed from the side.
Sliding genioplasty. In this case, the cut of the bone included the genial tubercle. CamachoMD.com
Sliding genioplasty. In this case, the cut of the bone included the genial tubercle.
Sliding genioplasty. In this case, the cut of the bone included the genial tubercle. There are plates and screws in place, holding the bone forward. CamachoMD.com
Sliding genioplasty. In this case, the cut of the bone included the genial tubercle. There are plates and screws in place, holding the bone forward.

Is a genial tubercle advancement performed with hyoid myotomy or hyoid suspension?

The hyoid is a bony structure that is located in the upper neck.

Drs. Riley and Powell operated on the hyoid as a part of the genial tubercle advancement.[6]

Three ways that the hyoid can be operated is by suspending the hyoid to the mandible or by bringing the hyoid bone closer to the thyroid cartilage that sits below the hyoid, in a suspension procedure.

The decision as to whether or not to add the hyoid surgery to the genial tubercle advancement is based on the anatomy of the patient, the training of the surgeon, and also on the patient counseling (risks, benefits, and alternatives).

What is the CPT Code for genial tubercle advancement?

The CPT code is 21199

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References:

1.         Kim, C.H., et al., Mandibular muscle attachments in genial advancement surgery for obstructive sleep apnea. Laryngoscope, 2019.

2.         Jung, S.Y., et al., Anatomical analysis to establish the optimal positioning of an osteotomy for genioglossal advancement: a trial in cadavers. Br J Oral Maxillofac Surg, 2018. 56(8): p. 671-677.

3.         Song, S.A., et al., Genial tubercle advancement and genioplasty for obstructive sleep apnea: A systematic review and meta-analysis. Laryngoscope, 2017. 127(4): p. 984-992.

4.         Hennessee, J. and F.R. Miller, Anatomic analysis of the Genial Bone Advancement Trephine System’s effectiveness at capturing the genial tubercle and its muscular attachments. Otolaryngol Head Neck Surg, 2005. 133(2): p. 229-33.

5.         Camacho, M., et al., Large maxillomandibular advancements for obstructive sleep apnea: An operative technique evolved over 30 years. J Craniomaxillofac Surg, 2015. 43(7): p. 1113-8.

6.         Riley, R., et al., Mandibular osteotomy and hyoid bone advancement for obstructive sleep apnea: a case report. Sleep, 1984. 7(1): p. 79-82.