Geometrical planning for the correction of orbital hypertelorism

Practical Considerations in Computerized Surgical Planning for Frontofacial Surgery

The field of frontofacial surgery has advanced considerably, building on the pioneering techniques of Paul Tessier, with computerized surgical planning (CSP) emerging as a critical component. CSP has enhanced the precision and efficiency of surgeries for craniofacial dysostoses and hypertelorism, resulting in improved outcomes. This review delves into the importance of understanding orbital anatomy and the crucial bony and soft tissue landmarks essential to the application of CSP in frontofacial procedures, encompassing Le Fort III and monobloc advancements, as well as the correction of hypertelorism.

Ocular Hypertelorism: Principles and Management

Background

Ocular hypertelorism (OH) was initially considered as un-differentiated congenital cranio-facial deformity, however, I.T Jackson mentioned it as teleorbitism, considering it as increase in the inter-canthal width, inter-pupillary as well as inter-orbital distance as a result of lateralization of the orbital complex in total. Furthermore, Sailer further refined it and included the distance from the lateral orbital wall, i.e. he denoted increased inter-orbital distance along with the distance between lateral orbital walls as true hypertelorism. This condition is rare and is seen in association with midline congenital defects affecting the cranio-facial region.

Classification and review of cases

The ideal time for the OH correction is usually between 5 and 8 years of age. However, the management of OH is complex, and several techniques have been described in literature for the same. Here, we describe our classification of OH, along with the evolution of the surgical aspects, the key treatment principles we follow, together with the types of the osteotomies and their indications. Furthermore, we delineate the four main principles that we have set for OH management.

Results

Though the improvement in appearance is seen immediately post-surgery, however, this challenging surgery faces a multitude and common postoperative complications which have been represented in this article. The surgeon needs both the technical expertise and an inclination towards aesthetics for the execution of such procedures.

Conclusion

It is preferred that the management of OH should be individualized as per the stage of the craniofacial growth and the psychosocial needs of the patient and the parents.

Addressing hypertelorism: Indications and techniques

From its first descriptions in the early 1920s to today's use of cutting guides via computer-assisted surgery, surgical techniques to address hypertelorism have progressed. The present article aims to provide historical background and an overview of the development of surgical techniques during the late 20th century and in recent years. First, a historical overview identifies the most important surgical advances leading to the present state of the art. Each major surgical innovation is described, to explain the changes in this surgical field, according to the type of approach. Then, a precise description of today's most recent practices is provided, with particular emphasis on the spectacular advances deriving from computer-assisted surgery. A thorough description of the use of cutting guides throughout the surgical phase is given.

Modeling age-specific facial development in Williams-Beuren-, Noonan-, and 22q11.2 deletion syndromes in cohorts of Czech patients aged 3-18 years: A cross-sectional three-dimensional geometric morphometry analysis of their facial gestalt

Three-dimensional (3D) virtual facial models facilitate genotype-phenotype correlations and diagnostics in clinical dysmorphology. Within cross-sectional analysis of both genders we evaluated facial features in representative cohorts of Czech patients with Williams-Beuren-(WBS; 12 cases), Noonan-(NS; 14), and 22q11.2 deletion syndromes (22q11.2DS; 20) and compared their age-related developmental trajectories to 21 age, sex and ethnically matched controls in 3-18 years of age. Using geometric morphometry statistically significant differences in facial morphology were found in all cases compared to controls. The dysmorphic features observed in WBS were specific and manifested in majority of cases. During ontogenesis, dysmorphic features associated with increased facial convexity become more pronounced whereas other typical features remained relatively stable. Dysmorphic features observed in NS cases were mostly apparent during childhood and gradually diminished with age. Facial development had a similar progress as in controls, while there has been increased growth of patients' nose and chin in adulthood. Facial characteristics observed in 22q11.2DS, except for hypoplastic alae nasi, did not correspond with the standard description of its facial phenotype because of marked facial heterogeneity of this clinical entity. Because of the sensitivity of 3D facial morphometry we were able to reach statistical significance even in smaller retrospective patient cohorts, which proves its clinical utility within the routine setting.

Frontofacial surgery in children and adolescents: techniques, indications, outcomes

The techniques of frontofacial surgery are most valuable in the clinical management of complex craniofacial deformity to achieve a range of functional and aesthetic gains in children from infancy to maturity. A variety of complex craniofacial osteotomies that can be used to separate the orbits from the skull base have been described. In addition, the combination of circumorbital release and pterygomaxillary disjunction allows advancement of the orbitomaxillary segment for powerful clinical benefit. For the purpose of this article, the principal frontofacial strategies include the monobloc frontofacial advancement by distraction (MBD), frontofacial bipartition advancement by distraction (BpD), orbital box osteotomy (FFBx), and frontofacial bipartition (FFBp). These techniques are broadly used for two purposes: to allow for the translocation of one or both orbits to correct orbitofacial disproportion (hypertelorism, vertical orbital dystopia, or a combination of both), or to advance the orbitomaxillary segment for orbital volume expansion and protection of the eye in syndromes featuring severe exorbitism (oculo-orbital disproportion). Here we describe aspects of our experience of frontofacial surgery in the Craniofacial Centre at Great Ormond Street Hospital for Children, London, with reference to the principles underpinning frontofacial surgical techniques, their challenges, and their impact on function and aesthetics.

Long-term results after 40 years experience with treatment of rare facial clefts: Part 2--Symmetrical median clefts

BACKGROUND

Median facial clefts are reconstructive challenges, requiring multiple operations throughout life. Long-term results are often still far from ideal and could be improved. Due to surgical intervention and diminished intrinsic growth potential, surgical results may change from initially good into a progressively disappointing outcome. If, however, the ideal timing and type of surgery are known, in combination with the intrinsic growth potential, the results can be ameliorated. A guideline for surgical treatment is given.

METHODS

Twenty patients with a pure symmetrical median cleft were evaluated on intermediate and long-term surgical results. The final result was scored based on severity of the initial and the remaining facial deformities, and the need for revisional surgery.

RESULTS

The long-term surgical outcome was initially good for each of the affected facial parts and the face in general, but worsened over time, especially in the zone of the nose. An adequate and stable result of hypertelorism correction was observed for both the orbital box osteotomy and medial faciotomy, even when performed at a young age.

CONCLUSIONS

The intrinsic growth restriction is mainly localised in the central midface. This leads to a complex and often unpredictable growth of the maturing face. It makes it difficult to achieve perfect reconstructions. Caution with surgical interventions of the nose at a young age is required. Once the face has matured, a midface advancement and secondary nose correction should be considered for satisfactory projection. Early referral to a specialised centre is essential.

Soft tissue assessment in midface advancement: the use of regional flaps to enhance facial projection

Classically, soft tissue repair when indicated is done before or after the skeletal mobilization especially in those cases that present midface deficiency with severe midline soft tissue restriction by scars or congenital affectation. The distraction osteogenesis method has contributed to improve substantially this problem elongating bones, muscles, and ligaments, but some situations need specific and more precise reconstruction of the subunits to gain in aesthetics. The labial-columella junction, the tip of the nose, and the more projecting point of the cheeks are one of these exigent anatomic areas, where only sophisticated reconstruction by flaps can improve facial proportions and projections.

Sincipital encephaloceles

An encephalocele is a protrusion of the cranial contents beyond the normal confines of the skull through a defect in the skull and the facial bones. Encephaloceles are classified according to their contents, site of exit through the skull/facial bones, and the path traversed through the face. Sincipital encephaloceles are the most common variety seen in the Asian population. Sincipital encephaloceles have been classified by Suwanwela and Suwanwela (1972) into frontoethmoidal, interfrontal, and those associated with craniofacial clefts. Correction of encephaloceles can be done in 1 stage or multiple stages and consists of excision of the encephalocele sac, repair of the bony defect, correction of hypertelorism/telecanthus, and correction of associated deformities such as trigonocephaly and the "long nose."

Stereolithography: a method for planning the surgical correction of the hypertelorism

Hypertelorism is a deformity characterized by an increase in interorbital distance. The treatment can be orbital mobilization, or if the malformation goes along with occlusal alterations, the indicated treatment is a facial bipartition with hemifacial rotation.The intention of the present study was to describe a surgical planning technique in locating the anatomic points and planes on a stereolithographic model of a patient with 0-14 fissure and its surgical application.

3D visualization and simulation in surgical planning system of orbital hypertelorism

Simulation and three-dimensional visualization of object motion is a prerequisite for any surgical planning system. Orbital hypertelorism is a disease, which is most commonly associated with craniofacial malformations. We have developed a surgical planning system for planning and evaluation of orbital hypertelorism surgery. In our system CT-based virtual surface models fitted by oriented bounding boxes (OBB) are manipulated. Three-dimensional motion as well as a correction surgery can be simulated. Both are controlled by collision detection. The computer-based interactive surgery simulation systems (CISSS) presented here can take virtual surgical operation and forecast facial features after the correction of orbital hypertelorism, our surgical planning is cheaper and faster than the current methods, surgical outcome was also better than the current methods.

From midface distraction to the “true monoblock”

In treating craniosynostosis, during the past 2 decades it has become accepted practice to perform fronto-orbital advancement and delay midfacial surgery. Corneal exposure,associated airway difficulties, and psychosocial problems remained untreated in these patients. Distraction osteogenesis assisted endoscopically offers an alternative treatment for patients with craniosynostosis, with the possibility of early midfacial surgery and simultaneous correction of the orbital-frontal deformity. The major benefit of gradual distraction is that it allows the surgeon to overcome the resistance of the overlying soft tissue envelope and offers the option of displacing the skeletal framework over greater distances, thus avoiding bone grafting. The technique also reduces morbidity and produces an improvement in form and function.