Associated relaps factors in Le Fort I osteotomy. A retrospective study of 54 cases

Abstract

Purpose

The Le Fort I osteotomy (LFI) procedure is commonly used to restore morpho-functional balance. The goal of maxillofacial surgeons with this procedure is to achieve occlusal stability. To identify factors associated with relapse after maxillary advancement in cleft lip and palate patients, the one-year post-operative stability of Le Fort I osteotomy was evaluated.

Methods

Horizontal and vertical relapse were analysed on lateral cephalograms by retrospectively using tracing paper in an orthonormal landmark in 54 patients undergoing unilateral cleft lip and palate surgery who were monitored at Nantes University Hospital. The lateral cephalograms were performed pre-operatively, immediately post-operatively, and after one year. Several variables were studied such as population data, intra-operative and post-operative surgical treatment, and surgical movement.

Results

At point A, the subspinale point, the mean advancement during surgery was 4.2 mm, with a relapse of 0.8 mm (20.1%). The mean downward movement was 2.0 mm in 26 patients who had a clockwise rotation of the maxilla, with a relapse of 0.6 mm (28.4%). The mean upward movement was 2.3 mm in 27 patients who had a counterclockwise rotation, with a deterioration of 0.2 mm (7%). A 7-millimetre surgical advancement corresponded to the threshold value beyond which relapse appeared to be significantly greater but still less than two millimetres in 75% of cases.

Conclusion

The degree of advancement appears to be the only variable correlated with the amplitude of the relapse.

Introduction

According to Veau and Delaire [1], patients with cleft lip and palate (CLP) have normal growth mechanisms but these are associated with abnormal anatomical conditions. Consequently, a functional therapeutic approach that preserves growth mechanisms and restores the anatomy while preserving orofacial functions is advocated in cleft lip and palate treatment. However, it is generally recognised that each surgical correction causes bona fide iatrogenic consequences responsible for maxillary hypoplasia [2], [3], [4], [5] in sagittal, vertical, and transverse directions.

To date, there is no consensus in regard to the surgical management of children with facial cleft. The Eurocleft project spearheaded by Shaw et al. [6], in fact, revealed that 194 different protocols were used at the 201 European treatment centres that were surveyed. The variability of the primary surgical techniques and therapeutic schedules make it difficult to analyse the causes of maxillary retrusion [7]. However, approximately 10 to 20% of children operated for a cleft present a class III malocclusion by maxillary retrusion that requires surgical treatment to correct dental and skeletal disharmony [8], [9], [10], [11], [12].

Correction of dento-skeletal disharmony by restoring a Class I occlusion and improvement of facial aesthetics are the main objectives of orthognathic surgery. Based on a study of the mutual balance of various bone structures of the face and skull, the craniofacial architectural and structural analysis developed by Delaire successively studies the skull (the vault and the base), the cervical spine, and the face to diagnose facial deformities. Its main purpose is to provide the surgeon a theoretical facial balance, unique to each individual, based on ongoing relationships between the face and the skull and the craniovertebral junction that can influence facial typology. However, occlusal stability of the Le Fort I osteotomy, which reflects restoration of a morphological and functional balance, should also be the goal of maxillofacial surgeons.

While the percentage of sagittal relapse in Le Fort I osteotomy in the general population is approximately 20% [13], patients operated for a facial cleft are more at risk of damage (20 to 40%) [14], [15], [16]. To date, studies on the subject have not allowed a consensus to be established regarding the management of this dysmorphosis sequela and the prevention of occlusal relapse. Indeed, the difficulty with this therapeutic care is that patients most often undergo multiple attempts at palate repair. There may be multiple risk factors, and there are numerous studies in the literature citing the presence or absence of correlations between the amplitude of relapse and the type of orthognathic surgery (single or bimaxillary jaw surgery) [17], [18], or the degree of intra-operative advancement [16], [17], [19], [20].

Moreover, although some authors did not find a significant correlation between the degree of intra-operative advancement and the amplitude of post-operative relapse [18], [21], [22], more recent studies have concluded that there is a higher risk of relapse in the context of a major surgical advancement [17], [20]. However, major advancement has not been well defined and, to our knowledge, no study has sought to define a threshold value at which the risk of relapse is increased.

The purpose of our study was to evaluate the stability at one year of Le Fort I osteotomy in a large and homogeneous population of patients operated for unilateral cleft lip and palate (UCLP) at the Maxillofacial Surgery Department of Nantes University Hospital. We hypothesize that a threshold value for advancement can be defined. The specific aims of the study were to evaluate correlation between relapse and population data, intra-operative and post-operative surgical treatment, and surgical movement.