Bilateral Sagittal Split Osteotomy: Correcting Jaw Imbalance and Enhancing Facial Harmony
A bilateral sagittal split osteotomy is a precise surgical procedure to correct the position of the lower jaw (mandible). This common orthognathic surgery addresses functional issues like malocclusion and aesthetic concerns such as a recessed chin or underbite. By carefully splitting and repositioning the mandible, a maxillofacial surgeon can achieve significant jaw advancement or setback, improving bite function, speech, and facial balance. The technique, a form of mandibular osteotomy, is performed entirely within the mouth, promoting stable healing and enhancing overall facial harmony.
Mr Shilen Patel, a Consultant Oral and Maxillofacial Surgeon in London, specializes in advanced jaw surgery, including this procedure. His dual medical and dental qualifications, combined with extensive NHS consultant experience, ensure expert assessment and personalized treatment for complex jaw conditions and facial balance.
To explore your options, contact us to schedule your consultation. You can also reach us via: Arrange your facial balance consultation
What is Bilateral Sagittal Split Osteotomy (BSSO)?
A Bilateral Sagittal Split Osteotomy (BSSO) is a surgical procedure performed by an oral and maxillofacial surgeon to correct the position of the lower jaw, or mandible. This technique involves making cuts on both sides of the jaw, allowing the tooth-bearing section to be moved forward, backward, or rotated to achieve a correct bite and improve facial balance.
A cornerstone of orthognathic surgery, this procedure addresses functional and aesthetic concerns from jaw misalignment. BSSO surgery is performed entirely from inside the mouth, leaving no visible external scars. Its versatility makes it the most common lower jaw surgery for correcting developmental jaw discrepancies.
Understanding Mandibular Repositioning
The “sagittal split” refers to how the mandible is divided. The cut is made longitudinally along the bone, splitting it into two segments while preserving the inferior alveolar nerve, which provides sensation to the lower lip and chin. This method allows for a large area of bone contact once the jaw is repositioned, promoting stable and predictable healing. The BSSO gives the surgeon control to move the jaw in multiple dimensions, making it an effective form of mandibular osteotomy.
Why is BSSO Performed? Correcting Jaw Imbalance
Lower jaw surgery is recommended when the mandible’s position causes functional problems or aesthetic disharmony that cannot be corrected with orthodontics alone. These imbalances can affect chewing efficiency, speech clarity, airway function, and the appearance of the lower face. Addressing these issues can improve a person’s quality of life.
The primary goal is to create a stable, functional bite where the upper and lower teeth meet correctly. This improves mastication, reduces excessive wear on the teeth, and can alleviate strain on the temporomandibular joints (TMJ). Aesthetically, a bilateral sagittal split osteotomy can create a more defined jawline, improve a recessed chin, or correct facial asymmetry, creating a more balanced facial profile.
Common Conditions Addressed by BSSO Surgery
- Mandibular Retrognathia: This condition, a “recessed chin” or “weak jaw,” occurs when the lower jaw is set too far back. Jaw advancement via BSSO can improve the profile and may open the airway to treat obstructive sleep apnea.
- Mandibular Prognathism: An “underbite,” this is when the lower jaw protrudes beyond the upper jaw. The procedure allows the surgeon to move the mandible backward into a correct position.
- Malocclusion: A poor fit between the upper and lower teeth, such as an open bite (where front teeth don’t meet) or a crossbite. BSSO can reposition the jaw to establish a correct and stable bite.
- Facial Asymmetry: When the lower jaw is deviated to one side, a BSSO can be used to centre it and restore facial symmetry.
The BSSO Procedure: A Step-by-Step Overview
The success of a bilateral sagittal split osteotomy relies on meticulous planning and precise surgical execution. The process is a collaboration between the maxillofacial surgeon and an orthodontist to ensure the teeth are aligned before and after the jaw is repositioned. The surgery is planned using diagnostic tools.
Virtual surgical planning (VSP) uses a 3D model of the patient’s skull created from CT scans. This allows the surgeon to perform the surgery digitally beforehand, planning movements to the sub-millimetre and fabricating custom surgical guides for use during the operation. This level of detail enhances precision and predictability.
From Planning to Rigid Internal Fixation
The procedure is performed under general anaesthesia and takes several hours. The surgeon makes incisions inside the mouth along the back of the lower jaw. The bone is then split in a controlled manner. Once separated, the jaw is moved into its pre-planned position. The final step is rigid internal fixation, where small titanium plates and screws secure the bone segments in their new orientation. These plates are biocompatible and typically remain in place permanently, providing the stability needed for the bone to heal correctly.
View data as table
| Phase | Description | Key Activities |
|---|---|---|
| Pre-operative Planning | Comprehensive assessment and preparation phase, often lasting several months. | Orthodontic treatment (braces), clinical photography, dental impressions, CT scans, and virtual surgical planning (VSP). |
| Surgical Phase | The operation itself, performed in a hospital under general anaesthesia. | Intraoral incisions, sagittal split of the mandible, repositioning of the jaw segment, and rigid internal fixation with plates/screws. |
| Post-operative Stabilization | The initial healing period immediately following surgery. | Hospital stay (1-2 nights), management of swelling and discomfort, use of guiding elastics, and transition to a liquid/soft diet. |
Navigating BSSO Recovery and Post-Operative Care
Recovery from a bilateral sagittal split osteotomy is gradual and requires patient commitment to post-operative instructions. The initial phase focuses on managing swelling, which is most significant in the first 72 hours and subsides over 2-3 weeks. Discomfort is managed with prescribed pain medication.
A modified diet is crucial for recovery. To protect the healing jaw, patients must adhere to a liquid or pureed diet for the first few weeks, progressing to a soft, non-chew diet for 6-8 weeks. Good oral hygiene is vital to prevent infection around the incision sites. Mr Shilen Patel provides detailed, personalised recovery plans to support patients through this period.
Managing Swelling, Diet, and Sensation Changes
Changes in nerve sensation are a common concern. The inferior alveolar nerve, which provides feeling to the lower lip, chin, and gums, is close to the surgical site. It is common to experience temporary numbness or a “pins and needles” sensation in this area after surgery. For most patients, sensation gradually returns over several weeks to months. While permanent numbness is a risk, its likelihood is reduced by a skilled surgeon. For general information on jaw surgery recovery, the NHS provides patient resources.
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| Recovery Phase | Duration (Approx.) | Key Milestones & Restrictions |
|---|---|---|
| Initial Hospital Stay | 1-2 nights | Swelling management, liquid diet initiated. |
| First Two Weeks | Weeks 1-2 | Peak swelling subsides, strict liquid/pureed diet, limited activity. |
| Early Healing | Weeks 3-6 | Transition to soft, non-chew diet. Return to work/school possible. |
| Bone Consolidation | Weeks 6-12 | Gradual return to a normal diet (avoiding hard/chewy foods). Post-operative orthodontics may begin. |
| Full Recovery | 3-12 months | Final orthodontic adjustments, sensation continues to improve, full return to all activities. |
Achieving Optimal Jaw Function and Facial Harmony in London
The goal of lower jaw surgery is to achieve a result where function and aesthetics are balanced. This requires a surgeon with a deep understanding of facial anatomy, dental occlusion, and aesthetic principles. A successful outcome is stable long-term, feels natural, and enhances facial appearance.
In London, patients can access consultant-led care. A surgeon dually qualified in medicine and dentistry, like Mr Shilen Patel, has a comprehensive perspective. This background ensures decisions consider the relationship between the teeth, jaws, joints, and facial soft tissues. This viewpoint is critical to achieving functionally sound and aesthetically pleasing results.
The Specialist Advantage: Precision and Personalised Outcomes
Choosing a specialist oral and maxillofacial surgeon with an NHS consultant post and experience in complex jaw surgery is advantageous. This expertise ensures meticulous surgical planning and execution, minimizing risks and optimizing outcomes. Each treatment plan is personalised to the patient’s anatomical needs and aesthetic goals. The aim is to deliver a result that improves function, enhances facial balance, and boosts self-confidence.
Is BSSO Right for You? Your Next Steps with a Consultant
Determining if a mandibular osteotomy is right for you begins with a thorough evaluation. This procedure is a significant undertaking, and the decision should be made with a specialist who can assess your clinical situation and discuss all options.
A consultation with an oral and maxillofacial surgeon is the first step. During this meeting, your facial structure, bite, and health will be evaluated. This is your opportunity to understand the benefits, review the treatment process, and have your questions answered. To explore how corrective jaw surgery could benefit you, schedule a detailed assessment. Arrange your facial balance consultation.
Conclusion
The decision to have lower jaw surgery is based on a balance of functional need and aesthetic goals. The key criterion is whether the procedure can provide a significant, lasting improvement to your health and quality of life. With modern planning techniques and surgical methods, outcomes are more predictable. Seek advice from a qualified and experienced specialist who can provide a clear diagnosis and a personalised treatment strategy. For expert guidance on your options, contact us or Arrange your facial balance consultation.
Frequently Asked Questions
How much can the lower jaw be moved with a sagittal split osteotomy?
The degree of movement depends on individual anatomy and surgical goals, but advancements of up to 10-12 millimetres are routinely achievable to correct a recessed jaw. For moving the jaw backward to fix an underbite, movements are typically more conservative. Mr Patel uses precise pre-operative 3D planning to determine the exact movement required for optimal function and aesthetics.
What is the statistical risk of permanent nerve numbness after a BSSO?
The inferior alveolar nerve, providing sensation to the lip and chin, is carefully protected during surgery. While temporary altered sensation is common in the initial weeks, data published in sources like the British Journal of Oral and Maxillofacial Surgery shows the risk of significant, permanent numbness is low, typically cited as less than 5% in the hands of an experienced surgeon.
Do the titanium plates and screws used to fix the jaw need to be removed later?
No, in the vast majority of cases, the hardware does not need to be removed. The small titanium plates and screws are biocompatible and designed to integrate with the bone permanently. Removal is only considered in the rare event of complications like infection or irritation, which occurs in a very small percentage of patients.
How long after a BSSO can I return to eating normal food?
A phased approach is essential for proper healing. Patients typically adhere to a liquid diet for the first 1-2 weeks, followed by a soft, non-chew diet for another 4-6 weeks. By the 8-week mark, most patients can begin reintroducing a normal diet, though very hard or chewy foods should be avoided until around 12 weeks post-surgery.
Will I need a genioplasty (chin surgery) in addition to the jaw surgery?
This depends on your unique facial structure and aesthetic goals. While a bilateral sagittal split osteotomy corrects the functional bite and jaw position, a genioplasty is often performed at the same time to achieve ideal chin projection and overall facial harmony. This combined approach is determined during your pre-surgical assessment using detailed facial measurements.
Will I have visible scars on my face after the procedure?
No, there will be no visible external scars. The entire bilateral sagittal split osteotomy procedure is performed through incisions made inside the mouth, along the gum line behind the back molars. This intraoral approach is a key advantage of the technique, ensuring all surgical work is concealed.
