Residency · Residency · Oral Maxillofacial Surgery
Alveolar Bone Grafting in Cleft Patients
Introduction
Alveolar bone grafting is a critical surgical intervention in the staged management of cleft lip and palate. The procedure restores bony continuity of the alveolar arch, supports eruption of the permanent canine, closes oronasal fistulae, and provides a foundation for future prosthetic rehabilitation. The OMFS surgeon typically performs this procedure during the mixed dentition period.
Goals of Alveolar Bone Grafting
The goals are to establish bony continuity across the alveolar cleft, provide bony support for eruption of the permanent canine (and occasionally the lateral incisor), close residual oronasal fistulae at the alveolar level, stabilize the premaxilla in bilateral cleft patients, support the alar base and improve nasal symmetry, and create bone stock for future dental implant placement if teeth are congenitally absent.
Timing and Classification
Primary Bone Grafting (Birth to 2 Years)
Primary bone grafting was performed at the time of lip repair or shortly after but has been largely abandoned due to adverse effects on maxillary growth. It was historically associated with midface retrusion and crossbite development.
Secondary Bone Grafting (6-11 Years)
Secondary bone grafting is the standard of care and is performed during mixed dentition. The optimal timing is when the permanent canine root is one-half to two-thirds formed, typically at ages 7 to 9. This allows the canine to erupt through grafted bone, providing optimal periodontal support. Timing is assessed by panoramic and periapical radiographs or CBCT.
Late Secondary (Adolescent) Grafting
Late secondary grafting is performed after canine eruption if secondary grafting was delayed or failed. Outcomes are less favorable, and the canine may erupt ectopically or require orthodontic traction. It may be combined with orthognathic surgery planning.
Tertiary Bone Grafting (Adult)
Tertiary grafting is performed in conjunction with implant site preparation or orthognathic surgery. It often requires larger graft volume and may need simultaneous ridge augmentation.
Preoperative Assessment and Planning
Orthodontic preparation involves arch expansion and alignment to widen the cleft gap and create space for grafting, coordinated with the orthodontist. Radiographic evaluation includes panoramic radiograph to assess canine position and root development, and CBCT for 3D cleft morphology. Dental assessment identifies retained or supernumerary teeth in the cleft site, which are extracted 6 to 8 weeks before grafting. Fistula assessment identifies and plans for closure of oronasal fistulae. Medical optimization ensures adequate nutrition and absence of active infection.
Surgical Technique
Graft Harvest
| Graft Source | Bone Type | Volume | Advantages | Disadvantages |
|---|---|---|---|---|
| Anterior iliac crest | Cancellous (gold standard) | Abundant | Highest success rates; large volume available | Donor site pain; gait disturbance; LFCN paresthesia |
| Calvarium | Cortical | Moderate | Low resorption rate; same surgical field | Limited volume; cranial complications; mainly cortical |
| Tibial plateau | Cancellous | Limited | Less morbidity than iliac crest | Insufficient volume for large defects |
| Mandibular symphysis/ramus | Corticocancellous | Small | Intraoral; no external scar | Limited quantity; risk to teeth/IAN |
| rhBMP-2 (off-label) | Osteoinductive | N/A | No donor site morbidity | Cost; swelling; controversial in pediatric use |
The anterior iliac crest (AICBG) is the gold standard donor site, providing abundant cancellous bone; the medial approach is preferred to minimize gait disturbance. Cranial bone (calvarium) is predominantly cortical with a lower resorption rate and is useful for smaller defects. The tibial plateau is an alternative cancellous source with limited volume. The mandibular symphysis or ramus provides an intraoral autogenous option for smaller defects. Bone morphogenetic protein-2 (rhBMP-2) is used off-label as a substitute for autogenous graft, avoiding donor site morbidity, though it remains controversial due to cost and potential complications.
Cleft Site Preparation
Mucoperiosteal flaps are elevated on both labial and palatal sides of the cleft. The nasal floor mucosa is identified and repaired (nasal layer closure), which is the critical first layer. Fibrous tissue is debrided from bony cleft margins to expose healthy bone. The palatal flap is released if necessary for tension-free closure.
Graft Placement
Particulate cancellous bone is packed into the cleft defect from the nasal floor to the alveolar crest. Bone must extend from the piriform rim superiorly to the alveolar ridge crest inferiorly. Slight overpacking is acceptable to account for resorption of 20 to 30%. Labial mucoperiosteal flaps are closed without tension, and water-tight closure is essential.
Palatal Fistula Closure
Simultaneous closure of oronasal fistulae at the alveolar and anterior palatal level is performed using a two-layer closure: nasal mucosa and oral mucosa with bone graft between layers. Persistent fistulae may require local flaps such as a tongue flap or buccal fat pad.
Postoperative Management
A soft diet is maintained for 6 weeks with no chewing on the graft site. Oral hygiene includes chlorhexidine rinses and gentle brushing avoiding the surgical site. Antibiotics, typically amoxicillin or clindamycin, are prescribed for 7 to 10 days. Physical activity is limited for 2 to 4 weeks, with iliac crest donor site pain management provided. Orthodontics resumes 6 to 8 weeks postoperatively, with orthodontic movement of the canine into grafted bone. Follow-up imaging with periapical or occlusal radiograph at 3 to 6 months assesses graft consolidation.
Outcome Assessment
Bergland Scale
| Type | Description | Bone Height | Interpretation |
|---|---|---|---|
| I | Normal alveolar bone height | >75% of interdental septum | Success |
| II | Adequate bone height | >50% but ≤75% of septum | Success |
| III | Partial bone bridge | <50% but some bone present | Partial failure |
| IV | No bone bridge | No bony continuity | Complete graft failure |
Types I and II represent success, reported in 80 to 95% of cases with autogenous iliac crest bone.
Markers of Success
Markers of success include canine eruption through grafted bone with adequate periodontal support, closure of oronasal fistula, radiographic evidence of a bony bridge across the cleft, and arch continuity supporting dental alignment.
Complications
Graft resorption is the most common complication and is expected to some degree; excessive resorption may require re-grafting. Fistula recurrence occurs in 5 to 15% of cases and may require secondary closure with flaps. Wound dehiscence risk increases with tension on closure. Donor site morbidity from the iliac crest includes pain, gait disturbance, lateral femoral cutaneous nerve paresthesia, and hematoma. Tooth damage may occur from injury to adjacent roots during flap elevation or graft placement. Infection may lead to graft loss.
Clinical Pearls
The optimal timing for secondary alveolar bone grafting is when the canine root is one-half to two-thirds formed, typically at ages 7 to 9. Anterior iliac crest cancellous bone remains the gold standard graft material with the highest success rates. Nasal floor closure is the most critical layer in the repair, as an inadequate nasal layer leads to graft loss and fistula recurrence. Orthodontic preparation (arch expansion) before grafting significantly improves surgical access and outcomes. rhBMP-2 avoids donor morbidity but should be used with careful patient selection and informed consent.
References
- Bergland O, Semb G, Abyholm FE. "Elimination of the Residual Alveolar Cleft by Secondary Bone Grafting and Subsequent Orthodontic Treatment." Cleft Palate Journal. 1986;23(3):175-205.
- Lilja J. "Alveolar Bone Grafting." Indian Journal of Plastic Surgery. 2009;42(Suppl):S110-S115.
- Cho-Lee GY, et al. "A Review of Secondary Alveolar Bone Grafting." International Journal of Oral and Maxillofacial Surgery. 2013;42(3):263-271.
- Canan LW, et al. "Human Bone Morphogenetic Protein-2 Use for Secondary Alveolar Bone Grafting." Journal of Craniofacial Surgery. 2012;23(5):1321-1326.