Monobloc and facial bipartition osteotomies: quantitative assessment of presenting deformity and surgical results based on computed tomography scans

Fronto-orbito-nasal advancement a surgical approach based on skull development in treatment of craniofacial deformities

The classical treatment of craniosynostosis is based on the fundamental work by Tessier. However, developmental aspects suggest modified osteotomy lines like fronto orbito nasal advancement combined with a modified midfacial distraction. This also makes it possible to take assess the different distances of the anterior displacement of the individual parts of the skull. Pioneering in therapy is less the syndrome itself than the accompanying symptoms such as respiration and intracranial pressure. For brain release we recommended (Joos 1998) the osteoclastic procedure according to Powiertowsky (1974) within the first 6 months of life. For further treatment frontoorbito-nasal advancement and modified midface distraction seem to achieve better results in enlarging the inner nose and a more harmonious profile.

Maxillary Changes Following Facial Bipartition - A Three-Dimensional Quantification

INTRODUCTION

Children with Apert syndrome have hypertelorism and midfacial hypoplasia, which can be treated with facial bipartition (FB), often aided by rigid external distraction. The technique involves a midline osteotomy that lateralizes the maxillary segments, resulting in posterior cross-bites and midline diastema. Varying degrees of spontaneous realignment of the dental arches occurs postoperatively. This study aims to quantify these movements and assess whether they occur as part of a wider skeletal relapse or as dental compensation.

METHODS

Patients who underwent FB and had high quality computed tomography scans at the preoperative stage, immediately postsurgery, and later postoperatively were reviewed. DICOM files were converted to three-dimensional bone meshes and anatomical point-to-point displacements were quantified using nonrigid iterative closest point registration. Displacements were visualized using arrow maps, thereby providing an overview of the movements of the facial skeleton and dentition.

RESULTS

Five patients with Apert syndrome were included. In all cases, the arrow maps demonstrated initial significant anterior movement of the frontofacial segment coupled with medial rotation of the orbits and transverse divergence of the maxillary arches. The bony position following initial surgery was shown to be largely stable, with primary dentoalveolar relapse correcting the dental alignment.

CONCLUSIONS

This study showed that spontaneous dental compensation occurs following FB without compromising the surgical result. It may be appropriate to delay active orthodontic for 6-months postoperatively until completion of this early compensatory phase.

Family of Crouzon Syndrome Represents the Evolution of the Frontofacial Monobloc Advancement Technique: From Immediate Movement to Monobloc Distraction to Monobloc Bipartition Distraction

Crouzon syndrome (CS) is an autosomal dominant disorder characterized by premature fusion of cranial sutures, midface and supraorbital ridge retrusion, exorbitism, and in some clinical scenarios strabismus, parrot-beaked nose, short upper lip and hypertelorbitism. Treatment of CS is overlapped with the beginning of craniofacial surgery and is grounded on morphologic and functional objectives. The authors reported on the outcomes and complications of family members (mother and 2 siblings) with CS, who were operated on by different techniques of frontofacial advancement and have attained skeletal maturity. Operations were performed in different moments throughout the last 3 decades of craniofacial surgery history. A 10-year-old Crouzon progenitor underwent a monobloc osteotomy with acute advancement, using rigid fixation and bone grafting in the osteotomy sites. An 8-year-old Crouzon daughter underwent gradual lengthening of a monobloc segment, using an external, institutionally made distracter device. In addition, a 10-year-old Crouzon son underwent gradual lengthening of a monobloc segment associated to facial bipartition, using an internal distracter device. After 30 years, the mother presented a mild relapse on the orbit level, but her children had satisfactory stable outcomes. The family members with CS have undergone different modifications of the monobloc approach based on different chronological momentum, from acute monobloc advancement, to monobloc distraction, to monobloc facial bipartition distraction.

Hypertelorism correction with facial bipartition and box osteotomy: does soft tissue translation correlate with bony movement?

OBJECTIVE

Hypertelorism may be corrected by either transcranial box osteotomy or facial bipartition. Despite radical bony resection, the associated soft tissue translation often seems disproportionate. The purpose of this study was to review bony and soft tissue movements in a series of 15 consecutive hypertelorism correction cases.

METHODS

Two surgical residents in training independently analyzed preoperative and postoperative axial and three-dimensional reconstructed computed tomography data from 15 consecutive patients undergoing facial bipartition (n = 7) or transcranial box osteotomy correction (n = 8) between 2001 and 2010. Anterior interorbital distance, lateral interorbital distance, midpoint globe distance, and globe protrusion were measured along with intercanthal distance and palpebral fissure width.

RESULTS

The mean preoperative anterior interorbital distance was 35.5 mm; postoperatively, there was a mean reduction of 9.5 mm, to 26 mm. The mean preoperative intercanthal distance was 48.1 mm; there was a mean reduction of 10.3 mm, to 37.8 mm. The mean preoperative midpoint globe distance was 69.5 mm; there was a mean reduction of 9.6 mm, to 59.9 mm. The mean preoperative globe protrusion was 17.6 mm; there was a mean reduction of 5 mm, to 12.6 mm (28.5%). The mean interclass correlation (a measurement of interrater congruency with 1 being complete agreement) was 0.85 CONCLUSIONS: Transcranial box osteotomy and facial bipartition correct hypertelorism. The medial canthal tendons, lateral canthal tendons, and globes move in proportion to the bony attachments. We observed a reduction in globe protrusion an average of 29%, therefore risking enophthalmos.

Salvage of calvarial bone graft using acellular dermal matrix in nasal reconstruction and secondary rhinoplasty for frontonasal dysplasia

Frontonasal dysplasia is a severe malformation composed of cranial, ophthalmic, nasal, upper lip, and palatal deformities. Reconstruction in these patients requires complex craniofacial efforts. A 19-year-old woman with frontonasal dysplasia was treated at our institution where she had undergone multiple prior reconstructive surgeries including facial bipartition and cantilevered calvarial bone graft for nasal reconstruction. She later presented with a palpable bone graft prominence, associated contour deformity, and an area of overlying paper-thin skin at the nasal tip. Although there was no ulceration, the threat of graft extrusion required immediate attention. The prominent bone graft tip was debrided, and the overlying soft tissue envelope was augmented using acellular dermal matrix. No surgical complication was encountered. The patient had successful salvage of the bone graft and a pleasing aesthetic outcome at 9 months of follow-up. The use of acellular dermal matrix has proven to be beneficial in the correction of nasal contour deformities given its soft, natural appearance, availability, affordability, and safety. Its use also avoids further donor site morbidity. We suggest acellular dermal matrix as a graft material in revision rhinoplasties for cases of acquired nasal contour deformity and threatened bone graft extrusion. This is the first report known to the authors using acellular dermal matrix during staged nasal reconstruction in a patient experiencing frontonasal dysplasia.

A mild case of frontonasal dysplasia: the rhinologic perspective

Frontonasal dysplasia (FND) is a congenital malformation characterized by hypertelorism, broad nasion with a midline cleft in the bony dorsum, midline defect of the frontal bone, absence of the nasal tip, and deformities in the nasal alar region. The clinician should be aware of the mild forms of FND. We presented absence of crista galli in a mild case of FND. Computed tomography scanning should assess the facial bones, nose, and paranasal structures. If a surgical correction is planned, this complete work-up prevents unexpected complications and complements the evaluation of paranasal deformities.

Interpupillary index: a new parameter for hypo-hypertelorism

AIM

To establish a new clinical index to evaluate the presence of hypo-hypertelorism with greater accuracy.

MATERIAL AND METHODS

After screening a wide range of population, 310 elementary school children (185 boys, 125 girls) aged 7-15 years were included in this study. For this cross-sectional study, a millimetre ruler was used. The anatomical interpupillary distance was measured by a modified Viktorin's method. In addition, inner and outer intercanthal distances were obtained. The data were analyzed by Student's t-test for two independent samples using SPSS for Windows. There were children with clinical hypertelorism (n = 92, group 1), children with large fronto-occipital circumference (FOC) (n = 101, group 2), and age- and sex-matched normal controls (n = 117, group 3). Due to variations in FOC among healthy subjects, we introduced a new practical concept for evaluation of interpupillary distance, namely the interpupillary index, the simple product obtained by dividing the interpupillary distance by the FOC, multiplied by 100.

RESULTS

The overall idiopathic benign macrocephalic children (group 2) had significantly (p < 0.001) larger interpupillary distances (6.13 +/- 0.36 cm) and FOCs (56.99 +/- 1.46 cm) than those of normal controls (5.70 +/- 0.26cm and 52.82 +/- 1.22 cm, respectively). But, the difference between the combined product of interpupillary distance and FOC, the interpupillary index, was not significant (10.76 +/- 0.50 and 10.79 +/- 0.35, respectively) (p > 0.05). On the other hand, the children with hypertelorism had significantly (p < 0.001) larger interpupillary distances (6.47 +/- 0.29cm) and FOCs (54.90 +/- 2.18cm) when compared with the controls. In addition, the interpupillary index was significantly (p < 0.001) higher (11.80 +/- 0.45) than both macrocephalic children (10.76 +/- 0.50) and controls (10.79 +/- 0.35). Intercanthal distances and intercanthal index of hyperteloric children were also significantly (p<0.001) larger than both macrocephalic children and controls.

CONCLUSION

This new index offers a new concept for more accurate evaluation of the presence of ocular hypo-hypertelorism.

The Craniofacial Dysostosis Syndromes: Current Surgical Thinking and Future Directions

Craniofacial dysostosis is the term applied to familial forms of craniosynostosis in which the sutural involvement generally includes the cranial vault, cranial base, and midfacial skeletal structures. The syndromic forms of craniofacial dysostosis (CFD) were initially described by Carpenter, Apert, Crouzon, Saethre and Chotzen, Pfeiffer, and others. In addition to the dysmorphic cranial features, affected individuals may have profound alterations in facial skeletal development. Surgical reconstruction requires thoughtfully sequenced and staged procedures with consideration for the individual's specific malformations, craniofacial growth patterns, and psychosocial needs.

Management of the CFD syndromes is surgical, but the indications and the timing, type, and effectiveness of each stage of reconstruction have not been well evaluated and remains as much an art as a science. This article reviews the specific characteristic clinical features of the CFD syndromes and presents current philosophy and rationale for the staging of reconstruction.