Maxillary Osteotomy and Advancement

The Le Fort I osteotomy is the standard means of repositioning the upper jaw in orthognathic surgery. A horizontal cut above the tooth roots separates the tooth-bearing maxilla from the midface, allowing the down-fractured segment to be advanced, impacted, lowered, or rotated to correct maxillary deficiency, vertical excess, and other deformities.

Definition

A Le Fort I osteotomy is a horizontal osteotomy of the maxilla above the apices of the teeth that separates the lower (tooth-bearing) maxilla from the upper midface, after which the mobilised segment is down-fractured, repositioned in three dimensions, and fixed, optionally being divided into segments to alter the arch transversely.

Scope

This topic describes the Le Fort I osteotomy and its movements — advancement, impaction, and segmentation for transverse correction — together with the vascular basis of the down-fracture and the determinants of post-surgical stability. It is a reference account of the technique and its evidence, not surgical instruction.

Core questions

• How does the down-fractured maxilla retain its blood supply once detached from the surrounding bone?
• Which maxillary movements — advancement, impaction, widening — are most and least stable over time?
• When is the maxilla segmented to correct a transverse discrepancy, and how does this compare with surgically assisted rapid maxillary expansion?

Key concepts

• Le Fort I horizontal osteotomy
• Down-fracture and pedicled palatal blood supply
• Maxillary advancement, impaction, and posterior repositioning
• Segmental osteotomy for transverse correction
• Bone grafting and rigid fixation
• Skeletal stability and relapse hierarchy
• Nasal and lip soft-tissue changes

Mechanisms

After a circumvestibular incision, the anterior, lateral, and medial maxillary walls and the pterygomaxillary junction are osteotomised, and the maxilla is down-fractured while remaining pedicled to the palatal soft tissues, which preserve its blood supply. The mobilised maxilla is then advanced, impacted, lowered, or rotated to a planned position and fixed with plates and screws, with bone grafting of resulting gaps when movements are large. Dividing the maxilla into two or more segments permits transverse expansion or levelling of the occlusal plane. The direction and amount of movement, the integrity of fixation, and grafting influence how stably the new position is maintained (Bell, 1975; Naran, 2018).

Clinical relevance

The Le Fort I osteotomy shows how the upper jaw can be repositioned in three planes on a soft-tissue pedicle, and how movement type relates to stability and soft-tissue change. The entry explains principles and evidence and is not a basis for individual surgical decisions.

Epidemiology

Le Fort I osteotomy is among the most frequently performed orthognathic procedures and is generally well tolerated, with bleeding and, less commonly, vascular or sinus complications recognised in large reviews (Chow, 2007). For transverse deficiency, segmental Le Fort I and surgically assisted rapid maxillary expansion offer different stability profiles that have been compared systematically (Starch-Jensen, 2016).

History

The osteotomy takes its name from the experimental midface fracture lines described by René Le Fort in 1901. Surgeons in the mid-twentieth century adapted the Le Fort I level for elective maxillary repositioning, and William Bell's work on the revascularisation of the down-fractured maxilla in the 1970s established the biological safety of the procedure and underpinned its modern, versatile use (Bell, 1975).

Debates

Stability of maxillary impaction and advancement versus inferior and transverse movements

Superior repositioning (impaction) and advancement of the maxilla are generally regarded as more stable than downward lengthening and surgical widening, the latter being more relapse-prone; the relative ranking guides planning and the use of grafting and rigid fixation.

Key figures

• William H. Bell
• Hans-Peter Obwegeser
• René Le Fort

Seminal works

• bell-1975
• naran-2018

Frequently asked questions

How does the upper jaw survive being cut free and moved?

In a Le Fort I osteotomy the maxilla is detached from the surrounding bone but left attached to the palatal soft tissues, which carry its blood supply. This pedicle keeps the down-fractured segment vascularised while it heals in its new position.

Why is the maxilla sometimes cut into pieces?

Segmenting the maxilla lets the surgeon change the width of the dental arch or level the bite, correcting transverse and occlusal-plane discrepancies that a single-piece movement cannot address.