Orthognathic Surgery — How It Works, Benefits & Recovery — Procedure Guide, Recovery & Risks | MyMedicPlus

Orthognathic surgery (from the Greek orthos — straight, gnathos — jaw) is corrective jaw surgery that repositions the maxilla (upper jaw), mandible (lower jaw), or both to correct skeletal malocclusion that cannot be resolved by orthodontics alone. Orthodontic treatment (braces) corrects the position of teeth within the bone; orthognathic surgery corrects the underlying skeletal discrepancy that causes the teeth to be in the wrong position relative to each other and to the face. The field was transformed in the 1970s by the development of rigid internal fixation using titanium plates and screws, which replaced the jaw wiring that was previously required for 6–8 weeks post-operatively. Today's orthognathic surgery combines virtual surgical planning (VSP) — three-dimensional planning on CT-based digital models — with custom surgical guides and pre-fabricated occlusal splints to achieve predictable, millimetre-accurate repositioning of the jaw bones. The three fundamental osteotomies are: the Le Fort I osteotomy (repositioning the maxilla in all three spatial planes — forward/backward, up/down, and rotation); the bilateral sagittal split osteotomy (BSSO — advancing or setting back the mandible); and the genioplasty (repositioning the chin). These are combined in bimaxillary surgery (operating both jaws simultaneously) in the majority of cases requiring significant correction, producing both superior functional and aesthetic results compared to single-jaw surgery.

Orthognathic surgery is indicated when skeletal jaw discrepancy causes functional problems — difficulty chewing, speech abnormalities, or obstructive sleep apnoea — and when the discrepancy is too large to be masked by orthodontic dental compensation alone. Class III skeletal pattern (prognathism — the lower jaw projecting forward relative to the upper) with a negative overjet (the lower front teeth in front of the upper front teeth) is the most common referral pattern; severe Class III frequently requires maxillary advancement (Le Fort I), mandibular setback (BSSO), or both. Class II skeletal pattern (retrognathia — the lower jaw recessed behind the upper, producing an 'overbite' appearance) typically requires mandibular advancement (BSSO) — the commonest single-jaw orthognathic procedure — with or without maxillary impaction for facial vertical height reduction. Vertical discrepancies — long face syndrome (anterior open bite) and short face syndrome (deep bite) — are corrected by maxillary impaction or downgrading, often combined with mandibular osteotomy. Facial asymmetry from unequal condylar growth (hemimandibular hyperplasia or hypoplasia) requires asymmetric movements of the mandible and sometimes maxilla to achieve facial symmetry. Obstructive sleep apnoea refractory to CPAP is increasingly managed by maxillomandibular advancement (MMA) — simultaneous advancement of both jaws by 10–12 mm to enlarge the entire upper airway — which achieves surgical cure in approximately 85% of patients. Surgery is performed only after facial growth is complete (typically 17–18 years in females, 18–21 years in males) and requires pre-surgical orthodontic preparation (usually 12–18 months) to align teeth within each jaw arch before skeletal correction.

Orthognathic surgery is performed under general anaesthesia with nasotracheal intubation (the endotracheal tube passes through the nose, leaving the mouth free for occlusal assessment during surgery). Pre-operatively, a 3D CT scan is used for virtual surgical planning — computerised movement of the jaw segments to the planned position, generation of custom surgical guides and a prefabricated acrylic intermediate splint that guides jaw repositioning intraoperatively. For Le Fort I osteotomy (upper jaw): a horizontal incision is made in the gingival sulcus above the upper teeth. A subperiosteal tunnel exposes the lateral and posterior maxilla; a horizontal osteotomy cut is made at the level of the nasal floor using an oscillating saw; the separated segment is 'down-fractured' and moved to the planned position using the intermediate splint for reference. Titanium L-plates and screws provide rigid internal fixation. For BSSO (lower jaw): subperiosteal dissection exposes the lateral and medial ramus; a sagittal split of the bone along precisely defined anatomical planes separates the tooth-bearing mandible from the ascending ramus without disturbing the inferior alveolar nerve. The mandible is advanced or set back using the final occlusal splint; bilateral rigid fixation is applied. For genioplasty: a horizontal osteotomy across the chin is repositioned in all dimensions and fixed. Total operative time for bimaxillary surgery is typically 3–5 hours; virtual planning and custom guides have significantly improved predictability and reduced operating time.

Orthognathic surgery delivers functional, aesthetic, and quality-of-life benefits that orthodontics alone cannot provide in patients with significant skeletal discrepancy. Chewing function improvement is the primary functional benefit — restoration of class I molar and canine occlusion normalises masticatory efficiency; clinical studies document significant improvement in bite force and masticatory performance within 6–12 months of surgery. Speech articulation improves in patients with significant malocclusion affecting sibilant and fricative production. Obstructive sleep apnoea: maxillomandibular advancement achieves a mean apnoea-hypopnoea index (AHI) reduction of over 75–80% in well-selected patients; approximately 85% achieve surgical cure (AHI <5/hr) — outcomes superior to any other surgical procedure for OSA. Aesthetic outcomes are frequently described by patients as life-changing: improved facial harmony, reduced mandibular or maxillary retrusion, and normalised facial proportions produce improvements in self-confidence and social confidence documented in multiple quality-of-life studies. Patient satisfaction with orthognathic surgery is consistently high — 85–95% satisfaction rates — with improvement on standardised oral health-related quality of life instruments (OHIP-14). Skeletal stability after modern rigid internal fixation is excellent: relapse rates for most movements are under 5–10% at 2 years, with mandibular advancement the most stable single movement.

Orthognathic surgery is major surgery with meaningful perioperative and longer-term risks that must be discussed with a specialist surgeon before proceeding. Inferior alveolar nerve (IAN) injury is the most significant complication of BSSO: temporary paraesthesia (altered or reduced sensation in the lower lip, chin, and teeth) affects up to 70% of patients immediately post-operatively, resolving in the majority over 3–18 months; permanent sensory deficit persists in approximately 5–10% depending on technique and the degree of nerve manipulation. Nasal changes: Le Fort I osteotomy consistently widens the alar base — an alar base cinch suture limits widening, but some residual flaring is common and should be discussed pre-operatively. Condylar resorption: progressive resorption of the mandibular condyles post-BSSO affects approximately 5% of patients (more common in females with pre-existing condylar changes or temporomandibular disorder), causing progressive relapse of the skeletal correction. Skeletal relapse: overall relapse rates for modern rigid fixation are low (under 10%) but are higher for very large movements, counter-clockwise rotation, or inadequate pre-surgical orthodontic preparation. Airway oedema: post-operative swelling can compromise the airway — patients are monitored for 24 hours post-operatively. Infection occurs in under 5% of cases. Hardware complications (loosening or fracture of titanium plates) are uncommon and may require removal under local anaesthesia after bony union.

Orthognathic surgery recovery follows a predictable pattern. Swelling peaks on days 3–5 post-operatively and resolves progressively over 4–8 weeks; bruising typically descends to the neck and upper chest before resolving. Oral nutrition: a liquid diet is maintained for the first 2 weeks; soft foods from weeks 3–6; normal diet after 6–8 weeks once healing is clinically confirmed. Elastic guiding bands across the teeth are worn to guide the bite into the planned occlusion — typically part-time wear for the first 4–6 weeks; jaw exercises begin progressively at week 6 to restore full mouth opening. Oral hygiene: chlorhexidine mouthwash and careful toothbrushing around intraoral wounds prevent infection. Nasal congestion from Le Fort I surgery resolves over 3–6 weeks with saline nasal irrigation. Post-surgical orthodontics begin 6–8 weeks post-operatively and continue for 6–12 months to finalise the occlusal detail and ensure long-term skeletal stability. IAN paraesthesia recovery continues for up to 18 months. Return to sedentary work at 2–3 weeks; physical activities at 6 weeks; contact sports at 3 months. Radiographic follow-up (OPG and lateral cephalogram) at 6 months and 12 months confirms skeletal stability.