bilateral sagittal split osteotomy: Definition, Uses, and Clinical Overview

Posted on | by drcosmetic

Definition (What it is) of bilateral sagittal split osteotomy

bilateral sagittal split osteotomy is a surgical procedure that cuts and splits the lower jaw (mandible) on both sides so it can be repositioned.
It is most commonly used in orthognathic (jaw) surgery to correct bite and jaw alignment problems.
It can be performed for functional reconstruction, facial balance, or both.
Fixation is typically achieved with small plates and screws to hold the jaw in its new position while it heals.

Why bilateral sagittal split osteotomy used (Purpose / benefits)

The primary purpose of bilateral sagittal split osteotomy is to reposition the lower jaw to improve how the teeth meet (occlusion) and how the jaw sits relative to the rest of the face. Because the mandible is a major structural element of the lower face, changing its position can influence both function (chewing, speaking, airway mechanics) and appearance (profile, symmetry, chin–jawline relationship).

In clinical practice, the “benefits” are generally discussed in terms of goals rather than guaranteed outcomes. Typical goals include improving bite stability, reducing strain on the jaw joints and muscles, and creating a more balanced facial proportion when the mandible is too far forward, too far back, or asymmetric. In reconstructive contexts, it may be used to restore alignment after trauma or to address growth-related jaw discrepancies.

From a patient perspective, the procedure is often part of a broader treatment plan that may include orthodontics (braces or aligners) and, in some cases, additional jaw procedures. The intended effect is structural: it addresses the underlying bone position rather than camouflaging the appearance at the skin or soft-tissue level.

Indications (When clinicians use it)

Common scenarios where clinicians may consider bilateral sagittal split osteotomy include:

  • Lower jaw set back too far (mandibular deficiency/retrognathia) contributing to bite problems
  • Lower jaw too prominent (mandibular excess/prognathism) with underbite tendencies
  • Mandibular asymmetry (jaw deviates to one side) affecting facial balance and occlusion
  • Class II or Class III malocclusion when orthodontics alone cannot correct the skeletal relationship
  • Functional concerns related to jaw position, such as chewing inefficiency or speech articulation issues (varies by case)
  • Preparation for comprehensive orthognathic correction when both jaws or the bite plane require coordinated changes
  • Selected reconstructive needs, such as post-traumatic malalignment, when a sagittal split approach is appropriate (varies by fracture pattern and healing status)

Contraindications / when it’s NOT ideal

Situations where bilateral sagittal split osteotomy may be less suitable, delayed, or replaced by another approach can include:

  • Active infection in the oral cavity or jaw region
  • Medical conditions that make major surgery or general anesthesia higher risk (varies by patient and clinician assessment)
  • Poor bone quality or anatomy that increases the risk of an unfavorable split (“bad split”), where another technique may be preferred (varies by clinician and case)
  • Severe periodontal disease or dental instability that complicates fixation and occlusion planning
  • Inadequate ability to participate in follow-up, postoperative care, and orthodontic coordination
  • Unrealistic expectations focused on a specific cosmetic “look” rather than achievable skeletal and occlusal goals
  • Ongoing growth in younger patients when the skeletal relationship is likely to change; timing decisions vary by clinician and case
  • Cases where the primary concern is limited to chin projection or soft-tissue contour, where alternatives (such as genioplasty, implants, or non-surgical options) may better match the goal

How bilateral sagittal split osteotomy works (Technique / mechanism)

bilateral sagittal split osteotomy is a surgical procedure, not minimally invasive and not non-surgical.

At a high level, the mechanism is repositioning: the surgeon creates controlled bone cuts on the right and left sides of the mandible, then separates (“splits”) the jaw in a way that allows the tooth-bearing segment to move relative to the back portion of the jaw (which includes the jaw joint region). Once the mandible is positioned according to the plan (for example, advanced forward, moved backward, rotated, or adjusted for asymmetry), it is stabilized.

Typical tools and modalities include:

  • Intraoral incisions (commonly inside the mouth), aiming to avoid external facial scars in many cases
  • Osteotomy instruments (such as surgical saws and/or chisels/osteotomes), selected by surgeon preference and anatomy
  • Rigid fixation hardware, commonly small plates and screws, to hold the segments during bone healing (specific systems vary by manufacturer and clinician)
  • Intermaxillary fixation aids, such as elastics or splints, used in some cases to help guide the bite during healing (use varies by clinician and case)
  • Imaging and planning tools, often including radiographs and/or 3D planning to map movements and occlusion (exact workflow varies)

Energy-based devices (like lasers for skin resurfacing) and injectables (fillers, neuromodulators) are not part of the mechanism of bilateral sagittal split osteotomy, because the goal is skeletal repositioning rather than superficial contouring.

bilateral sagittal split osteotomy Procedure overview (How it’s performed)

Below is a typical high-level workflow. Specific steps, sequencing, and adjuncts vary by clinician and case.

  • Consultation: Review concerns (bite, function, facial balance), medical history, dental history, and prior orthodontic work.
  • Assessment / planning: Clinical exam and bite analysis, imaging, and coordination with orthodontics. A surgical plan is created for the desired jaw movements and final occlusion.
  • Prep / anesthesia: The procedure is commonly performed under general anesthesia. Preoperative preparation may include dental models, splints, and standardized photographs (varies by clinician).
  • Procedure: Incisions are made (often inside the mouth). Controlled cuts are created on both sides of the mandible, the bone is split, and the jaw is repositioned to match the plan and bite relationship. Fixation hardware is placed to stabilize the new position.
  • Closure / dressing: Incisions are closed. Some patients may have guiding elastics or a splint, depending on the plan.
  • Recovery: Monitoring for swelling, bite stability, nerve-related symptoms, and oral wound healing. Follow-up visits typically address occlusion guidance, hygiene, diet progression, and coordination with orthodontic finishing (varies by clinician and case).

Types / variations

There is more than one way to categorize “types” of bilateral sagittal split osteotomy. Common variations include:

  • Direction of movement
  • Mandibular advancement (moving the lower jaw forward)
  • Mandibular setback (moving the lower jaw backward)
  • Rotation and vertical adjustments (used to refine occlusion and facial proportions; details vary by plan)

  • Asymmetry correction (differential movement between sides)

  • Planning pathway

  • Orthodontics-first: braces/aligners are used to decompensate the teeth before surgery, then surgery refines skeletal alignment

  • Surgery-first: surgery is performed earlier, with orthodontics focused on finishing afterward (case selection varies by clinician and case)

  • Fixation strategy

  • Rigid internal fixation with plates and screws is common

  • The exact plate design, screw type, and configuration vary by surgeon preference and manufacturer

  • Combined procedures

  • BSSO may be paired with maxillary surgery (such as Le Fort I osteotomy) when both jaws contribute to malocclusion
  • It may be combined with genioplasty (chin surgery) if chin position needs separate adjustment from the lower jaw position

  • Adjunctive soft-tissue procedures may be considered in select cosmetic plans, but they are not inherent to BSSO

  • Anesthesia choices

  • General anesthesia is typical for full orthognathic procedures
  • Local anesthesia or sedation-only pathways are generally not standard for BSSO in most settings, but protocols can vary by clinician and facility

Pros and cons of bilateral sagittal split osteotomy

Pros:

  • Addresses the skeletal cause of many bite and jaw-alignment problems rather than masking them
  • Can improve occlusion (how teeth meet) when orthodontics alone is insufficient
  • Often uses intraoral incisions, which may limit visible external scarring in many cases
  • Allows meaningful correction of mandibular asymmetry in appropriately selected patients
  • Can be coordinated with broader orthognathic plans for comprehensive facial balance (varies by clinician and case)
  • Typically aims for structural stability once bone healing is complete, though long-term changes can occur

Cons:

  • It is major surgery with a recovery period that can include swelling, diet modification, and time away from normal activities
  • Risk of altered sensation (numbness/tingling), especially involving the lower lip and chin due to proximity to the inferior alveolar nerve; recovery varies
  • Potential for infection, bleeding, or wound-healing issues, as with other intraoral surgeries
  • Possibility of an unfavorable split or fixation-related complications; risk depends on anatomy and technique
  • The final outcome depends on planning accuracy and orthodontic coordination, and may require adjustments over time
  • Results can be influenced by skeletal relapse or bite changes; stability varies by clinician and case

Aftercare & longevity

Aftercare for bilateral sagittal split osteotomy is generally focused on protecting healing bone segments, maintaining oral hygiene around intraoral incisions, and supporting stable occlusion while swelling resolves. Most patients experience a period where diet texture, speaking comfort, and daily routine are temporarily altered, but the timeline and intensity vary by individual factors.

“Longevity” for this procedure is best understood as long-term structural change, because the jaw is repositioned and then heals in that position. Even so, durability is influenced by several variables:

  • Surgical planning and fixation: the planned movements, bone contact, and stability of fixation can affect how reliably the position is maintained
  • Orthodontic finishing and retention: teeth may continue to shift if retention is inconsistent; coordination varies by clinician and case
  • Anatomy and bite forces: muscle pull, joint mechanics, and pre-existing asymmetry can influence adaptation over time
  • Healing biology: general health, nutrition status, and individual variation in bone healing can affect recovery experience
  • Smoking and oral health: smoking is commonly discussed as a risk factor for wound and bone healing in surgery in general; individual risk varies
  • Follow-up adherence: scheduled checks help clinicians monitor occlusion, hardware tolerance, and sensory recovery

Because this is not a skin resurfacing or filler-based procedure, factors like sun exposure are not central drivers of the core skeletal result, though they can still influence overall facial aging and appearance.

Alternatives / comparisons

The “best comparison” depends on what problem is being solved: bite alignment, jaw position, facial aesthetics, or a combination.

Common alternatives or related approaches include:

  • Orthodontic treatment alone (braces/aligners): may correct tooth alignment and mild bite issues, but cannot fully correct significant skeletal jaw discrepancies. This is sometimes described as dental compensation rather than skeletal correction.
  • Le Fort I osteotomy (upper jaw surgery): targets the maxilla rather than the mandible. Some patients need maxillary surgery alone, while others need combined upper and lower jaw surgery to align occlusion and facial proportions (varies by clinician and case).
  • Genioplasty (chin osteotomy): moves the chin segment without repositioning the whole lower jaw. It may help with chin projection or vertical chin height, but it does not correct a true mandibular malocclusion on its own.
  • Chin implant: can change chin projection and contour, but it does not correct the bite and does not reposition the mandible. Implant-based outcomes and risks vary by material and manufacturer.
  • Mandibular distraction osteogenesis: gradually lengthens bone in selected cases, often considered when large advancements are needed or in specific reconstructive contexts. It differs in timeline and mechanics from a single-stage split osteotomy.
  • Non-surgical facial contouring (fillers/neuromodulators): can camouflage mild profile concerns or soften masseter prominence, but does not change jawbone position or correct occlusion. This may be appropriate when goals are purely cosmetic and skeletal alignment is acceptable.

A practical way to think about these options is that bilateral sagittal split osteotomy is a structural jaw repositioning operation, while many alternatives focus on teeth alignment, chin-only changes, or soft-tissue camouflage.

Common questions (FAQ) of bilateral sagittal split osteotomy

Q: Is bilateral sagittal split osteotomy painful?
Discomfort is expected after major jaw surgery, especially during the early swelling phase. Pain experience varies widely, and clinicians use anesthesia and postoperative pain-control strategies that differ by facility and case. Many patients describe pressure, tightness, and soreness rather than a single constant “sharp pain.”

Q: Will there be visible scarring?
Incisions are commonly made inside the mouth, which often limits visible external facial scarring. However, scarring can still occur within the oral tissues, and the exact incision design varies by surgeon. In some complex cases, additional incisions may be used for access, though this is not the typical cosmetic goal.

Q: What kind of anesthesia is used?
bilateral sagittal split osteotomy is most often performed under general anesthesia. This supports airway management, precise jaw positioning, and patient comfort. The exact anesthesia plan depends on patient health factors and the surgical setting.

Q: How long is the downtime or recovery?
Recovery is usually described in phases: early swelling and limited diet, followed by gradual return to routine activities, and longer-term bite settling and sensory changes. The overall timeline varies by clinician and case, especially when orthodontics is part of the plan. Many people need time away from strenuous activity and significant social commitments during the early healing period.

Q: How long do results last?
Because the procedure repositions bone, changes are generally intended to be long-lasting after healing. That said, stability can be affected by factors such as relapse tendencies, bite changes, orthodontic retention, and individual anatomy. Long-term outcomes vary by clinician and case.

Q: How much does bilateral sagittal split osteotomy cost?
Costs vary widely based on geography, facility fees, anesthesia, surgeon experience, imaging/planning needs, and whether additional procedures or orthodontics are included. Insurance coverage, when applicable, can change out-of-pocket costs substantially depending on the indication and documentation requirements. A personalized estimate typically requires a full clinical evaluation.

Q: Is it “safe”? What are the main risks?
All surgery carries risks, and jaw surgery has procedure-specific considerations. Commonly discussed risks include bleeding, infection, unfavorable splits, bite changes, hardware issues, and altered sensation due to nerve proximity. The likelihood and severity of risks vary by clinician and case.

Q: Will I have numbness in my lip or chin?
Temporary numbness or altered sensation in the lower lip and chin is a well-known concern because the inferior alveolar nerve runs within the mandible. Some people recover sensation gradually over time, while others may have longer-lasting changes. The degree and duration vary by anatomy, movement magnitude, and surgical technique.

Q: Do I need braces or aligners before or after?
Many treatment plans involve orthodontics before surgery, after surgery, or both, because the teeth must fit the new jaw position. Some cases are managed with a surgery-first approach, but it is not appropriate for every bite pattern. The timing and necessity vary by clinician and case.

Q: Can this procedure help with facial asymmetry?
It can be used to address skeletal asymmetry of the lower jaw, especially when asymmetry affects the bite and chin–jawline relationship. Planning typically evaluates both bone and dental midlines, as well as how soft tissue drapes over the new jaw position. The visible change depends on the type of asymmetry and overall facial anatomy.