Treatment Plan for Short Mandible with Faster Maxillary Growth
The treatment plan depends critically on the patient's age and skeletal maturity: growing patients require growth modification and timing considerations, while skeletally mature patients need orthognathic surgery with maxillomandibular advancement. 1, 2
Age and Growth Status Assessment
Determine skeletal maturity first, as this fundamentally dictates the treatment approach and timing. 2
Growing patients (pre-adolescent/adolescent): Consider early intervention only when functional, esthetic, or psychosocial factors necessitate it, recognizing that secondary corrective procedures may be required after initial surgery due to unpredictable effects on subsequent facial growth. 2
Skeletally mature patients (adults): Proceed with definitive orthognathic surgery without concern for future growth changes. 1, 3
Treatment for Skeletally Mature Patients
Maxillomandibular advancement (MMA) surgery is the definitive treatment, consisting of bilateral sagittal split ramus osteotomies with rigid internal fixation for the mandible and Le Fort I osteotomy with rigid internal fixation for the maxilla. 1, 4
Surgical Planning Specifics
Advancement magnitude: An advancement of 10-15mm of both the maxilla and mandible is necessary to effectively correct the skeletal discrepancy when maxillomandibular abnormality exists. 1
Surgical sequence: Simultaneous repositioning of the maxilla and mandible is the standard approach, with the maxilla positioned first using an interim splint constructed from sectioned models mounted on a semi-adjustable articulator from a face bow transfer. 3, 5
Stabilization protocol: Use direct osseous fixation, suspension wires, and maxillomandibular fixation for six weeks, followed by an additional four weeks of guided mandibular function with skeletal elastics. 5
Medical Necessity Criteria
Orthognathic surgery is medically necessary only when skeletal deformities contribute to significant masticatory dysfunction and the severity precludes adequate treatment through dental therapeutics and orthodontics alone. 1
Specific measurement criteria include:
- Antero-posterior discrepancies
- Maxillary/mandibular antero-posterior molar relationship discrepancy
- Vertical discrepancies
- Transverse discrepancies
- Total bilateral maxillary palatal cusp to mandibular fossa discrepancy 1
Orthodontic Coordination
A modified surgery-first approach can reduce total treatment time to 12 months by performing a short presurgical alignment phase to correct significant crowding while controlling incisal angulation, followed by surgery, then utilizing the increased bone turnover in the postsurgical phase for efficient tooth movement. 6
Treatment for Growing Patients
Delay definitive surgical correction until skeletal maturity whenever possible, as there is limited predictability of orthognathic surgical procedures performed during growth and unknown effects on subsequent facial growth. 2
When Early Intervention is Necessary
If functional, esthetic, or psychosocial factors necessitate early surgical intervention:
Accept the possibility of secondary corrective procedures after the initial corrective surgery once growth is complete. 2
Coordinate presurgical and postsurgical edgewise orthodontic therapy with systematic postsurgical neuromuscular rehabilitation. 3
Critical Pitfalls to Avoid
Performing definitive surgery during active growth without counseling families about the high likelihood of needing revision surgery. 2
Incorrect maxillary positioning during surgery: The correct position of the maxilla is required to determine the ultimate position of the mandible—there is no room for error with this step if the procedure is to be accurate. 5
Inadequate stabilization: Insufficient fixation duration leads to relapse and poor outcomes. 5
Pursuing surgery for primarily aesthetic concerns without documented functional impairment, as this is not considered medically necessary. 1