Maxillomandibular Advancement/BSSO/Genioglossus Advancement for Severe Obstructive Sleep Apnea: Key Surgical Steps Summary

Authors: Daniel Hawkins, DMD, FACS; Thomas S. Lee, MD, FACS

Published 2/7/2026

This article summarizes the surgical technique for Maxillomandibular Advancement (MMA) for patients with severe obstructive sleep apnea (OSA) and blocked airways who are intolerant of CPAP, as demonstrated by Dr. Hawkins from the Department of Oral and Maxillofacial Surgery at the University of Pittsburgh. MMA is considered the most effective procedure for severe OSA, demonstrating an average reduction in AHI by 80% and a success rate of 85% in a large meta-analysis.

MMA is indicated for OSA patients presenting with concentric and severe lateral wall collapse. The patient discussed in the video had an AHI of 81, was intolerant of CPAP, and had concentric collapse noted on drug-induced sleep endoscopy. After surgery, the patient’s AHI was reduced from 81 to 11 at six months postoperatively. The virtual surgical plan projected the maxilla to move forward nearly a centimeter, the mandible nearly 10 mm, and the pogonion (chin) forward 17.5 mm after genioglossus advancements.

Key Steps of the Maxillomandibular Advancement Procedure

Preparation and Preoperative Planning

• Occlusion and Aesthetics Discussion: Discuss with patients not undergoing full orthodontic treatment that postoperative adjustments to the occlusion may be limited. Also, reassure patients that the cosmetic outcome is typically either positive or neutral, as the surgery corrects the bimaxillary retrusion often associated with their airway issues.
• Arch Bar Placement: Place Erich arch bars on the mandibular arch using 26 gauge wires on anterior teeth (including two teeth per wire to prevent extrusion) and 24 gauge wires on posterior teeth. Secure the arch bar distal/posterior to the last tooth to prevent loosening. Place a hybrid arch bar in the maxillary arch, ensuring 6 mm or 8 mm screws and avoiding tooth roots.
• Occlusal Reduction: Perform occlusal reductions according to the virtual surgical plan using a diamond round bur, taking off no more than a half millimeter from any tooth cusp.
• Custom Hardware: Custom hardware is used to ensure the accuracy and strengthen the fixation of the advancement. Note that although vendor regulations recommend an intermediate splint, it is the authors’ opinion that in cases of maxillomandibular advancement for OSA that  the custom hardware can allow for proceeding without an intermediate splint for the positioning of the maxilla, which is typically used in traditional orthognathic surgery. The custom hardware can also increase rigidity of the fixation in these cases that require large maxillary advancements.

Le Fort I Osteotomy

• Incision and Dissection:
  • Place corneal shields to protect the patient’s eyes.
  • Begin the incision with a guarded tip Bovie 3 to 5 mm above the mucogingival junction, cutting through the mucosa and then changing angle 90 degrees down to bone.
  • Perform subperiosteal dissection to expose the piriform rim, zygomatic buttress, and infraorbital nerve.
  • Dissect the nasal mucosa from the nasal floor and lateral nasal walls, staying on bone and submucosally to avoid tears.
  • Lift the caudal septum away from the maxillary crest.
• Custom Cutting Guide and Osteotomy:
  • Place a custom hybrid cutting guide (bone and occlusal-borne) to dictate the osteotomy.
  • Drill predictive fixation holes before using the saw.
  • Use a thin reciprocating blade to complete the osteotomy.
  • If maxillary cant correction is required, cut a wedge guided by the custom cutting guide. On the contralateral side, no wedge is removed as the maxilla will be moved inferiorly.
  • Protect the nasal mucosa during the medial portion of the osteotomy.
  • Complete the osteotomies near the zygomatic buttress, being careful to stay in the subperiosteal plane to prevent buccal fat extrusion.
• Lateral Nasal Wall Osteotomy: Use a guarded osteotome, hugging the nasal floor to stay inferior to the inferior turbinates and avoid fracturing superiorly.
• Pterygomaxillary Junction Separation:
  • Use a small osteotome to score the posterior sinus wall and ensure the posterior extent reaches the pterygoid plates. A change in sound indicates reaching the pterygoid plate.
  • Use a curved osteotome to fracture the pterygoid plates in an anterior, inferior, and medial (AIM) direction.
  • Palpate the hamular notch intraorally to feel the osteotome and prevent perforation of the palatal mucosa.
  • Direct the osteotome 102 degrees to the sagittal plane of the posterior nasal spine to achieve a clean cut through the pterygomaxillary junction (Type A fracture).
  • Bleeding Risk: Be aware of the risk of damaging the internal maxillary artery, which is superior and medial to the pterygoid hamulus. This osteotomy should be performed last before down-fracture.
• Down-Fracture and Mobilization:
  • Use a three-prong spreader (Smith spreader) and hand pressure to down-fracture the maxilla, placing the spreader on the piriform or zygomatic buttress, not the thin central maxillary sinus bone.
  • Use Tessier and Rowe disimpaction forceps in a lateral and twisting motion (not straight anteriorly) to stretch the soft palatal tissues and achieve adequate advancement.
• Contouring and Fixation:
  • Reduce the lateral nasal walls with a rongeur and any interferences with a round carbide bur.
  • Reduce the bony nasal spine to prevent future septal deviation.
  • Place the custom Le Fort plates, aligning them with the predictive screw holes on the piriform and zygomatic buttress. Do not fully tighten screws initially to allow for minor adjustments. If the hardware does not fit passively, further reduction of interferences is needed.
  • Verify the vertical position of the maxilla by measuring from the medial canthus to a reference point on the incisors and canines.
  • Place a cortical-cancellous allograft block in the gap, typically secured with a wire or screws.
• Closure: Perform a V-Y advancement for mucosal closure to lengthen the upper lip, using an interrupted stitch at the V-Y point and a running chromic suture for the mucosal portion. Close the posterior part of the incision first for ease of access. The closure should be watertight.

Bilateral Sagittal Split Osteotomy (BSSO)

• Incision and Dissection:
  • Begin the mucosal incision at least 5 mm below the mucogingival junction. Back elevate mucosa towards the teeth and cut down to avoid mucosal overhang.
  • Perform subperiosteal dissection to expose the lateral body and ramus.
  • Strip the tenacious temporalis fibers superiorly and maintain a subperiosteal plane during medial dissection to protect the lingual nerve.
  • Identify the lingula, the bony projection where the inferior alveolar nerve enters the mandible medially.
• Osteotomy Cuts:
  • The BSSO can be broken down into three main cuts: medial, sagittal, and lateral, with a fourth cut self-propagating from the medial cut. Dr. Hawkins prefers one continuous motion with a reciprocating saw for a smooth transition.
  • Medial Cut: Horizontal osteotomy superior to the lingula.  It then transitions at a 45 degree angle for a smooth transition to the sagittal cut.
  • Sagittal Cut: Carried in the sagittal plane adjacent to the mandibular teeth. The speaker prefers a thin sagittal cut, leaving only cortical bone on the lateral aspect to keep the inferior alveolar nerve in the dentate segment.
  • Lateral Cut: Through the most prominent lateral bulge, typically between the first and second molars. The speaker prefers cutting only through the lateral cortex at the inferior border.
• Splitting the Mandible:
  • Use a series of sequential osteotomes (starting with a thin spatula) to slowly propagate the sagittal split, which should open from anterior to posterior.
  • Use an inferior border elevator and a three-prong spreader (Smith spreader) simultaneously for controlled propagation, applying bodily pressure rather than torquing the lateral segment.
  • Dissect the inferior alveolar nerve free from the proximal segment.
• Fixation and Condylar Seating:
  • Place the final splint and apply heavy elastics and wire to achieve maxillomandibular fixation (MMF) in the presurgical occlusion.
  • Rotate the condylar segment superiorly for intraoral access for fixation.
  • Fixate the mandible using a six-hole plate and monocortical screws, with the partner surgeon fixating the mini plates to the distal segment.
  • Condyle Seating: This is a crucial step. Apply firm posterior and superior pressure to seat the condyle while aligning the inferior borders of the mandible.
  • Bicortical Screws: Place bicortical screws more posteriorly, superior to the inferior alveolar nerve, using a trocar and U retractor. These are positional screws, not lag screws, to maintain the gap and prevent condyle torquing. Use of both plates and bicortical screws is preferred in MMA patients to increase strength and stability.
  • Release the MMF and passively check the occlusion, ensuring the condyles are seated with slight posterior and superior pressure.

Genioglossus Advancement

The purpose of genioglossus advancement is to address retrolingual and hypopharyngeal airway collapse, which can be significantly influenced by the muscles attached to the genial tubercle on the posterior surface of the anterior mandible.

Key points regarding the procedure’s purpose and related anatomy:

• Muscles Affected: The genioglossus and geniohyoid are critical muscles that affect retrolingual and hypopharyngeal airway collapse and attach to the genial tubercle.
• Function of Muscles: The genioglossus muscle is mainly responsible for the protrusion of the tongue, and the geniohyoid muscle assists in moving the hyoid bone superiorly and anteriorly.
• Impact on Airway: Based on the location and function of these muscles, they have a significant impact on obstruction at the retropharyngeal and hypopharyngeal levels.
• Surgical Goal: Genioglossus advancement aims to advance the portion of the bone containing the genioglossus attachment (the genial tubercle).

Incision and Dissection:

• • Inject local anesthesia.
  • Begin the mucosal incision from canine to canine, ensuring it is positioned to leave a superior cuff of mentalis for re-suspension and to prevent a “witch’s chin” deformity.
  • Identify the mental nerves bilaterally by dissecting along the inferior border first, then dissecting superiorly to them to make the subsequent incision safely.
• Custom Cutting Guide and Osteotomy:
  • Place the custom occlusal cutting guide for genioglossus advancement.
  • Drill predictive holes while pressing the guide firmly into the occlusion.
  • Use a reciprocating saw to make the initial bicortical osteotomies, ensuring the genial tubercle and genioglossus attachment are captured while avoiding tooth roots and the mental nerve. The cut should taper laterally to prevent winging.
  • Ensure the cut is deep enough to go through both cortices but avoids transecting the genioglossus.
  • Use a spatula osteotome to complete the last portions of the osteotomy.
• Advancement and Fixation:
  • Grasp the mobile segment using a screw as a handle.
  • Place monocortical screws in the mobile segment first, then align the predictive holes on the superior segment and fixate the custom hardware.
• Grafting and Closure:
  • Place particulate allograft (e.g., Vivigen bone allograft) in the gap created by the advancement to achieve bony continuity.
  • Resuspend the mentalis with three interrupted 3-0 Vicryl sutures to avoid chin drooping.
  • Close the mucosa with a running 3-0 chromic gut suture in a watertight fashion.
  • Close the buccal trocar incisions with interrupted 5-0 fast-absorbing gut.
  • Inject Marcaine for postoperative pain control.
  • Leave the patient in heavy elastics for two to four weeks postoperatively.