Residency · Residency · Oral Maxillofacial Surgery
Surgery-First Approach in Orthognathic Surgery
Overview
The surgery-first approach (SFA) eliminates or significantly reduces presurgical orthodontic treatment before orthognathic surgery. Surgery is performed first, followed by post-surgical orthodontics to finalize occlusion. The approach is based on the regional acceleratory phenomenon (RAP), whereby surgical trauma accelerates bone remodeling and tooth movement. SFA reduces overall treatment time from 2-4 years with the conventional approach to 1-1.5 years, though it requires careful patient selection and precise surgical planning.
Historical Context
The surgery-first approach was first described by Behrman in 1972 for isolated mandibular prognathism. Nagasaka et al. popularized the modern concept with systematic protocols in 2009. The approach was initially met with skepticism due to concerns about stability and unpredictable orthodontic outcomes, but a growing body of literature now supports comparable outcomes to conventional sequencing in selected cases.
Rationale and Biological Basis
Regional Acceleratory Phenomenon (RAP)
Frost described the RAP in 1983 as a complex reaction of tissues to noxious stimuli. Surgical osteotomies induce intense local bone remodeling, resulting in transient regional osteopenia and increased bone turnover. Tooth movement through this remodeling bone is 2-3 times faster than through normal bone. The RAP peaks at 1-2 months post-surgery and persists for 4-6 months, creating a window of accelerated orthodontics that coincides with active post-surgical treatment.
Benefits of Eliminating Presurgical Orthodontics
In conventional protocols, presurgical orthodontics decompensates the teeth by removing dental camouflage. This often worsens the patient's facial appearance and function for 12-18 months before surgery. The SFA provides immediate skeletal correction, improving aesthetics and psychosocial well-being early in treatment. Patient motivation and compliance improve when visible results occur at the start of treatment.
Patient Selection
Ideal Candidates
Ideal candidates have minimal to no dental crowding (less than 4 mm) or crowding that can be resolved post-surgically. They should have a relatively flat or mild curve of Spee, normal or near-normal dental inclinations with minimal dental compensation, and a Class I molar relationship (dental) with skeletal discrepancy -- essentially a skeletal problem with minimal dental compensation. A favorable facial growth pattern, adequate interdental bone support for planned post-surgical tooth movement, and a motivated patient who understands the protocol are also important.
Relative Contraindications
Relative contraindications include severe crowding requiring premolar extractions (though some protocols allow this), significant transverse discrepancies requiring surgical expansion, severely compensated dentition (such as retroclined lower incisors in Class III), a canted occlusal plane requiring presurgical leveling, active periodontal disease, and complex multi-piece Le Fort I cases.
Absolute Contraindications
Absolute contraindications include the inability to achieve a stable surgical occlusion with three-point contact, an unwilling patient who cannot accept temporary malocclusion adjustments, and skeletal discrepancies requiring precise dental decompensation for safe osteotomies.
<image>Clinical photographs comparing the conventional orthognathic treatment sequence (presurgical orthodontics, surgery, post-surgical orthodontics) with the surgery-first approach timeline, showing the difference in overall treatment duration and the earlier improvement in facial profile with SFA</image>
Surgical Planning Considerations
Predicting the Final Occlusion
The surgeon and orthodontist must predict where teeth will end up after post-surgical orthodontic treatment. A diagnostic setup (physical or digital) is performed to determine the target occlusion. Surgical splints are fabricated to the predicted post-orthodontic occlusion rather than the current one, requiring significant experience and precise communication between surgeon and orthodontist.
Achieving Intraoperative Stability
The surgical occlusion may not have tight interdigitation since dental alignment is not yet completed. Emphasis is placed on achieving stable three-point contact (bilateral posterior and anterior). Heavier fixation may be required, including four-point fixation in the maxilla and bicortical screws in the mandible. Some protocols use temporary orthodontic anchorage devices (TADs) for post-surgical elastic traction, and surgical hooks or brackets are placed at the time of surgery or immediately postoperatively.
Virtual Surgical Planning in SFA
VSP is particularly valuable for SFA as it allows digital dental setup to predict final tooth positions, simulation of both surgical and orthodontic outcomes, fabrication of surgical splints based on the predicted final occlusion, and assessment of potential interferences and airway changes. The predicted post-orthodontic dental models can be 3D printed for splint fabrication.
Surgical Technique Modifications
Fixation
Rigid internal fixation is essential, relying on stable osteosynthesis rather than dental interdigitation. In the maxilla, four-point fixation (bilateral piriform rim and bilateral buttress) is recommended. In the mandible, bicortical screws (three per side) or combination plate and screw fixation is used. Bone grafting at osteotomy gaps should be considered to enhance stability.
Intermaxillary Fixation
Light guiding elastics are started immediately postoperatively rather than rigid MMF. Class II or Class III elastics settle the occlusion, guiding the dental segments into the planned occlusal relationship. Early bracket bonding within 2 weeks of surgery begins orthodontic control.
Anchorage Considerations
TADs are placed intraoperatively or within the first few weeks, providing stable anchorage points for post-surgical orthodontic mechanics. They are useful for controlling the vertical dimension and preventing unwanted dental movements.
<image>Lateral cephalometric tracings showing a Class III patient treated with the surgery-first approach: preoperative tracing with dental compensation, immediate post-surgical tracing showing skeletal correction with temporary dental malocclusion, and final tracing after post-surgical orthodontics showing harmonized skeletal and dental relationships</image>
Post-Surgical Orthodontics
Timeline
Bracket bonding occurs within 1-2 weeks of surgery, with some protocols bonding at the time of surgery. Initial alignment and leveling takes 1-3 months, accelerated due to the RAP. Space closure and detailing require 3-6 months. Total post-surgical orthodontics lasts 6-12 months, significantly faster than the conventional post-surgical phase.
Key Orthodontic Principles
Clinicians should take advantage of the RAP window by beginning active treatment early and using light continuous forces to maximize efficiency in remodeling bone. Skeletal stability is monitored with serial cephalograms, and coordination with the surgeon for any secondary adjustments including elastics and TADs is essential.
Stability and Outcomes
Skeletal Stability
Multiple studies report comparable skeletal stability to conventional sequencing. Horizontal relapse is 0.5-1.5 mm, similar to conventional protocols. There is some concern about increased vertical relapse in SFA, particularly in open bite cases. Long-term stability data beyond 2 years are increasingly supportive but still limited compared to conventional protocols.
Occlusal Outcomes
Comparable final occlusal results by ABO scoring are achieved with conventional treatment, though some studies report slightly inferior occlusal outcomes in complex cases. Post-surgical orthodontic compliance is critical for achieving optimal results.
Treatment Time
| Parameter | Surgery-First Approach | Conventional Approach |
|---|---|---|
| Presurgical orthodontics | None or minimal | 12-18 months |
| Total treatment time | 14-18 months | 24-36 months |
| Time reduction | 30-50% | — |
| RAP-accelerated tooth movement | Yes (2-3x faster) | No |
| Patient satisfaction | Generally higher | Standard |
Mean total treatment time is 14-18 months with SFA versus 24-36 months with the conventional approach, representing a 30-50% reduction in overall treatment duration. Patient satisfaction scores are generally higher with SFA.
Controversies and Debates
Stability Concerns
Critics argue that operating on compensated dentitions may compromise skeletal stability and that the lack of dental interdigitation at the time of fixation may allow more relapse. The counter-argument is that rigid fixation, not dental interdigitation, is the primary determinant of stability.
Predictability
The conventional approach allows precise dental decompensation before surgery, yielding a more predictable final result. SFA requires prediction of post-orthodontic tooth positions, introducing additional uncertainty. However, digital planning tools including VSP and digital setups have improved predictability substantially.
Case Selection Bias
Most SFA studies select simpler cases with minimal crowding and mild compensation. Whether SFA is appropriate for complex cases remains debated, though indications are expanding as experience and technology improve.
Clinical Pearls
The success of SFA depends on meticulous planning and close surgeon-orthodontist collaboration. SFA should not be attempted without a committed orthodontic partner experienced in the protocol. VSP and digital dental setups should be used to reduce uncertainty in splint fabrication. TADs placed intraoperatively are invaluable for post-surgical orthodontic control. Patients must be warned that they will have a temporary malocclusion after surgery that will be corrected orthodontically. Close monitoring in the first 6-8 weeks is important, as this is when the RAP window is most active. SFA is not appropriate for every case -- patient selection is the single most important determinant of success. When in doubt, the conventional approach should be the default; SFA is an optimization, not a revolution.
<image>Intraoral photographs showing the occlusal progression of a surgery-first patient: preoperative compensated Class III malocclusion, immediate post-surgical occlusion with initial instability and guided elastic use, and final occlusion after 10 months of post-surgical orthodontics</image>
References
- Nagasaka H, et al. Surgery-first approach in orthognathic surgery. J Oral Maxillofac Surg. 2009.
- Liou EJ, et al. Surgery-first accelerated orthognathic surgery: orthodontic guidelines and setup for model surgery. J Oral Maxillofac Surg. 2011.
- Hernandez-Alfaro F, Guijarro-Martinez R. On a definition of the surgery-first approach in orthognathic surgery. J Oral Maxillofac Surg. 2014.
- Yang L, et al. Surgery-first approach versus conventional orthognathic approach: a systematic review and meta-analysis. J Oral Maxillofac Surg. 2017.
- Peiro-Guijarro MA, et al. Surgery first in orthognathic surgery: a systematic review. Int J Oral Maxillofac Surg. 2016.
- Frost HM. The regional acceleratory phenomenon: a review. Henry Ford Hosp Med J. 1983.
