Validation of a 3D methodology for the evaluation and follow-up of secondary alveolar bone grafting in unilateral cleft lip and palate patients

Three-dimensional evaluation of secondary alveolar bone grafting in patients with unilateral cleft lip and palate: A 2-3 year post-operative follow-up

OBJECTIVES

The present study aims to quantitatively assess secondary alveolar bone graft (SABG) resorption in unilateral cleft lip, alveolus and palate (UCLAP) patients in a 2-3 year longitudinal follow-up setting by using a validated 3D protocol. Furthermore, the potential relation of SABG resorption with maxillary canine position and a number of patient-related factors was investigated.

METHODS

UCLAP patients who underwent SABG and had good quality CBCT images at the following timepoints were included in the study: pre-operative (T0), immediate (T1), 6 months (T2) and either 1-2 years (T3) or 2-3 years (T4) post-operative. The final bone grafted region was defined on the T1 scans and refined in the registered T0 scans. The bone graft after resorption was determined by applying threshold-based segmentation on the registered T2, T3 or T4 scans within the segmented bone graft volume. The position of the canines was determined at every timepoint at the cleft and non-cleft side.

RESULTS

Forty-five UCLAP patients (mean age 9.0 ± 1.3 years) were included. In the first 6 months after SABG, 43.6% bone resorption was recorded. 2-3 years post-operative, 56% bone resorption was found if the maxillary canine was not yet erupted and 42.7% if it erupted through the graft. The vertical position of the canines was significantly higher on the cleft side at T3.

CONCLUSIONS

The present study reports significant SABG resorption over time. However, no correlation was found between SABG resorption and canine position, nor between other patient-related factors.

Validation and comparison of 2D grading scales and 3D volumetric measurements for outcome assessment of bone-grafted alveolar clefts in children

BACKGROUND

Several methods have been proposed to assess outcome of bone-grafted alveolar clefts on cone beam computed tomography (CBCT), but so far these methods have not been compared and clinically validated.

OBJECTIVES

To validate and compare methods for outcome assessment of bone-grafted clefts with CBCT and provide recommendations for follow-up.

METHODS

In this observational follow-up study, two grading scales (Suomalainen; Liu) and the volumetric bone fill (BF) were used to assess the outcome of 23 autogenous bone-grafted unilateral alveolar clefts. The mean age at bone grafting was 9 years. The volumetric BF was assessed in five vertical sections. The bone-grafted cleft outcome was based on a binary coding (success or regraft) on a clinical multidisciplinary expert consensus meeting. Grading scales and volumetric assessment were compared in relation to the bone-grafted cleft outcome (success or regraft). Reliability for the different outcome variables was analyzed with intra-class correlation and by calculating kappa values.

LIMITATIONS

The study had a limited sample size. Clinical CBCT acquisitions had a varying tube current and exposure time.

RESULTS

Volumetric 3D measurements allowed for outcome assessment of bone-grafted alveolar clefts with high reliability and validity. The two grading scales showed highly reliable outcomes, yet the validity was high for the Suomalainen grading scale but low for the Liu grading scale.

CONCLUSIONS

Volumetric 3D measurement as well as the Suomalainen grading can be recommended for outcome assessment of the bone-grafted cleft. Yet, one must always make a patient-specific assessment if there is a need to regraft.

Effect of adjuvant autologous platelet concentrates on secondary repair of alveolar clefts: A systematic review and meta-analysis

OBJECTIVE

To review the existing evidence on the adjuvant use of autologous platelet concentrates (APCs) with iliac crest bone graft (ICBG) in the reconstruction of the secondary alveolar cleft.

METHODS

Electronic databases were searched systematically until November 2022. Clinical trials comparing the three-dimensional radiological outcomes of patients who underwent secondary alveolar bone grafting (SABG) with ICBG and APCs to those with ICBG alone and the radiological outcomes assessed 6 months after surgery were included. Two authors performed the study selection and the assessment of the risk of bias. Meta-analysis was performed using the random-effects model to determine the risk ratio (RR) for developing wound dehiscence and the mean difference (MD) with a 95% confidence interval (CI) for the percentage of newly formed bone.

RESULTS

Nine studies (seven RCT and two CCT) were included with a low to high risk of bias. At the 6-month follow-up, the study group revealed insignificant results regarding the percentage of newly formed bone (MD = 6.49; 95% CI: -0.97, 13.94; p = .09; χ2  = 0.01; I2  = 71%). In addition, the overall risk of developing wound dehiscence was lower in the study group (RR = 0.34; 95% CI: 0.15, 0.78; p = .01; χ2  = 0.67; I2  = 0%).

CONCLUSION

Currently, there is insufficient evidence to support the adjuvant use of APCs with ICBG on enhanced bone regeneration following secondary alveolar bone grafting. However, combining ICBG and APCs might be beneficial in reducing the risk of developing wound dehiscence.

Bioglass 45S5, a relevant alternative to autogenous harvesting for secondary alveolar bone grafts in clefts? Retrospective study of one hundred surgeries

The secondary alveolar bone grafting (SABG) step restores the continuity of the alveolar bone necessary for dentition. Faced with the complications of autografts, synthetic biomaterials such as Bioglass (BG) 45S5 have been proposed. The objective was to evaluate the success rate of SABG with the addition of BG 45S5 and to highlight the prognostic factors. Patients who underwent operation between 2015 and 2021 and had follow-up cone-beam computed tomography (CBCT) were analyzed. Multivariate analysis was performed to determine factors influencing radiographic success. A total of 102 SABG were analyzed. They were unilateral total cleft lip and palate (49, 48.0%). The mean age at surgery was 9.32 ± 3.09 years. Surgeries were performed mainly outside a syndromic context and without a family history after orthodontic preparation. The radiographic success rate at 1 year was 80.4%. Mixed dentition stage (odds ratio [OR] = 7.3, p = 0.024), absence of syndromic context (OR = 20.7, p = 0.024) and female sex (OR = 4.88, p = 0.021) were factors predictive of surgical success. The use of BG 45S5 instead of autograft is relevant for SABG, with a 1-year success rate of over 80%. The stage of mixed dentition, the absence of syndromic context, and female sex were factors for good prognosis.

Evaluation of Alveolar Bone Reconstruction In Clefts With Early Or Late Secondary Bone Grafting: Use Of The 3d Kamperos score

There is still no consensus on the optimal age for alveolar grafting. In order to decide on the success of this graft, the best known radiographic assessments lacks precision. Kamperos recently proposed a 3D CBCT score that simultaneously assesses alveolar bone height and thickness, as well as the nasal floor level. The aim of this study was to apply this new score and compare it between an early secondary alveolar grafting « ESAG » (4-7 y) and a late secondary alveolar grafting « LSAG » (8-11 y) surgery group. A total of 32 cases of ESAG and 17 of LSAG were analysed. On 3D imaging, the median age of ESAGs was 10 years and 15 years for LSAGs. In the ESAGs, 78% of the permanents canines were not on the arch compared to 18% in the LSAGs. In both groups, the reconstruction of the nasal floor was very adequate but the height and thickness appeared less good in the ESAGs. The final score was higher in LSAG (Chi2, P < 0.005). The analysis of the alveolar bone with the Kamperos score is accurate and relevant but it should preferably be performed in the permanent dentition phase. This is because the area of rhizalysis of the primary teeth and the follicular sac of the erupting permanent teeth influence the presence of effective bone.

Machine learning in 3D auto-filling alveolar cleft of CT images to assess the influence of alveolar bone grafting on the development of maxilla

BACKGROUND

Machine learning based auto-segmentation of 3D images has been developed rapidly in recent years. However, the application of this new method in the research of patients with unilateral cleft lip and palate (UCLP) is very limited. In this study, a machine learning algorithm utilizing 3D U-net was used to automatically segment the maxilla, fill the cleft and evaluate the alveolar bone graft in UCLP patients. Cleft related factors and the surgery impact on the development of maxilla were analyzed.

METHODS

Preoperative and postoperative computed tomography images of 32 patients (64 images) were obtained. The deep-learning-based protocol was used to segment the maxilla and defect, followed by manual refinement. Paired t-tests and Mann-Whitney tests were performed to reveal the changes of the maxilla after surgery. Two-factor, two-level analysis for repeated measurement was used to examine the different trends of growth on the cleft and non-cleft sides of the maxilla. Pearson and Spearman correlations were used to explore the relationship between the defect and the changes of the maxillary cleft side.

RESULTS

One-year after the alveolar bone grafting surgery, different growth amount was found on the cleft and non-cleft sides of maxilla. The maxillary length (from 34.64 ± 2.48 to 35.67 ± 2.45 mm) and the alveolar length (from 36.58 ± 3.21 to 37.63 ± 2.94 mm) increased significantly only on the cleft side while the maxillary anterior width (from 11.61 ± 1.61 to 12.01 ± 1.41 mm) and posterior width (from 29.63 ± 2.25 to 30.74 ± 2.63 mm) increased significantly only on the non-cleft side after surgery. Morphology of the cleft was found to be related to the pre-surgical maxillary dimension on the cleft side, while its correlation with the change of the maxilla after surgery was low or not statistically significant.

CONCLUSION

The auto-segmentation of the maxilla and the cleft could be performed very efficiently and accurately with the machine learning method. Asymmetric growth was found on the cleft and non-cleft sides of the maxilla after alveolar bone graft in UCLP patients. The morphology of the cleft mainly contributed to the pre-operation variance of the maxilla but had little impact on the maxilla growth after surgery.