The challenge of maxillary growth in cleft lip and palate

The management of maxillary hypoplasia in patients born with a cleft lip and palate (CLP) constitutes a major therapeutic challenge. Traditionally, the correction of the resulting Class III malocclusion requires waiting for skeletal maturity to perform a LeFort I osteotomy. In this context, bone-anchored maxillary protraction (BAMP) has emerged as an interceptive strategy during adolescence, with the aim of stimulating maxillary growth and ultimately avoiding complex orthognathic surgery.

Evaluate the actual benefit of the BAMP protocol

This retrospective study, conducted by the universities of Arizona and Michigan, analyses the clinical outcomes of 23 patients (isolated cleft palate, unilateral or bilateral CLP) who underwent BAMP treatment between 2015 and 2024. The objective was to compare the promises of the technique with the clinical reality of patients with a history of multiple surgeries. The researchers specifically evaluated changes in overjet, the prevalence of hardware complications and the revision rate. The challenge is to determine whether BAMP genuinely reduces the need for major surgery or whether it simply increases the burden of care through repeated corrective procedures.

Methodology of the 10-year retrospective study

This study is based on a retrospective review of clinical records conducted over a 10-year period, from 2015 to 2024, within a university institution. The objective was to evaluate the clinical outcomes of bone-anchored maxillary protraction (BAMP) in patients presenting with maxillary hypoplasia associated with cleft lip and palate (CLP).

The study population consists of 23 patients presenting with the following diagnoses:

• Isolated cleft palate: n = 1
• Unilateral cleft lip and palate: n = 13
• Bilateral cleft lip and palate: n = 8

The experimental protocol involved the placement of BAMP devices at a mean age of 12.4 ± 1.0 years. The mean duration of active treatment was 24.8 ± 14.1 months. Follow-up included the assessment of the maxillo-mandibular relationship by measuring the overjet during the physical examination, before and after treatment.

The primary endpoints included:

• The change in overjet during treatment.
• The complication rate and the frequency of hardware revision surgeries (maxillary and mandibular plates).
• The level of patient compliance regarding the wearing of dental elastics.
• The ultimate need for orthognathic surgery (LeFort I osteotomy) at skeletal maturity.

Statistical analyses sought to establish correlations between the outcomes (evolution of the overjet) and variables such as the Veau classification or the surgical history related to the cleft.

Clinical results and efficacy of the BAMP treatment

The study included 23 patients (1 isolated cleft palate, 13 unilateral and 8 bilateral cleft lip and palate) followed for a mean duration of 24.8 ± 14.1 months. The mean age at device placement was 12.4 ± 1.0 years. An improvement in the Class III skeletal relationship was observed in 57% of the patients, with a reduction in negative overjet at the end of treatment. The authors specify that no correlation was established between the severity of the cleft (Veau classification) or the number of previous surgical procedures and the extent of the change in overjet.

Complications and equipment maintenance

The complication rate is particularly high, affecting 78.3% of the cohort (n=18). Hardware failures (loosened, bent or broken plates) affected 16 patients (69.5%). A notable disparity is observed depending on the implantation site:

These complications required revision surgery to adjust or replace the material in 9 patients.

Compliance and long-term surgical outcome

Therapeutic compliance proved to be poor, with 56.5% of patients (n=13) reporting irregular wear of intermaxillary elastics. Regarding the primary objective of avoiding orthognathic surgery at skeletal maturity, the results are as follows:

• Of the 16 patients who completed the full protocol, 12 (75%) still required a LeFort I osteotomy.
• Only 4 patients (25%) were able to avoid major surgery following BAMP treatment.

Analysis of the results and clinical impact

The results of this retrospective study conducted on 23 patients cast doubt on the systematic use of BAMP in patients with cleft lip and palate (CLP). While an improvement in overjet was observed in 57% of subjects, the primary objective — avoiding orthognathic surgery at skeletal maturity — was achieved in only 25% of those who completed the protocol. Clinically, this means that for 3 out of 4 patients, BAMP delays the need for surgery without eliminating it, while imposing a heavy treatment burden.

The associated morbidity is concerning: 78.3% overall complications. The fragility of the hardware (loosened, bent or broken plates in 69.5% of cases) is particularly marked in the maxilla (75% hardware failure versus 43% in the mandible), which is probably explained by the specific bone quality at the cleft sites. These failures require frequent surgical revisions (39% of patients), increasing the burden of care for children who have already undergone multiple surgeries.

Limitations and perspectives

The study emphasises a major hurdle: compliance. With 56.5% inconsistency in wearing elastics, the efficacy of the traction force is compromised. Although retrospective and limited to a sample of 23 patients, this series highlights a discrepancy between the theoretical benefit of BAMP and the clinical reality in a CLP context. Unlike non-syndromic Class III patients where BAMP yields conclusive results, the bone architecture and compliance of CLP patients appear to drastically limit its benefit. For the practitioner, these data suggest re-evaluating the benefit/risk ratio before initiating a BAMP protocol, the final outcome remaining predominantly a LeFort I osteotomy.

Summary of results

This retrospective study conducted on 23 patients (2015-2024) shows that despite an improvement in overjet in 57% of subjects, the BAMP protocol presents a complication rate of 78.3%, dominated by hardware failures (69.5%). Ultimately, 75% of the patients who completed the treatment (average of 24.8 months) still required LeFort I orthognathic surgery.

In practical terms, for the practitioner:

• Increased selectivity: Re-evaluate the indication for BAMP in cleft lip and palate (CLP), as the surgical burden induced by plate revisions (39% of cases) rarely offsets the effective growth gain.
• Patient information: Systematically inform families that the risk of requiring orthognathic surgery at skeletal maturity remains at 75%, despite two years of appliance therapy.
• Material vigilance: Prioritise the monitoring of maxillary plates, whose failure rate (75%) is significantly higher than that of mandibular plates, and rigorously validate compliance with elastic wear at the first signs of clinical stagnation.

Technical glossary of the study

Bone Anchored Maxillary Protraction (BAMP): Therapeutic protocol used during adolescence to stimulate maxillary growth and limit the worsening of a Class III malocclusion through the use of bone anchors and elastics.

LeFort I osteotomy: Maxillary advancement surgery performed at skeletal maturity to correct residual maxillary hypoplasia.

Overjet (sagittal discrepancy): Clinical measurement of the maxillomandibular relationship in the sagittal plane, used in this study as the primary endpoint to assess the improvement of occlusion after treatment.

Veau classification: Cleft lip and palate classification system used by the authors to analyse a possible correlation between the cleft type and the clinical evolution of the overjet.

Class III skeletal relationship: Malocclusion characterised by a negative sagittal discrepancy (negative overjet), resulting here from maxillary hypoplasia common in patients with cleft lip and palate.

Hardware malfunction: Mechanical complications related to the bone anchorage device, including loose, bent or broken plates, observed in 69.5% of the patients in the study.

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