Neurosurgical considerations on the anatomy of the medial canthus in children

Craniofacial surgery and anterior skull base surgical techniques require an intimate knowledge of periorbital structures. The medial orbital anatomy is especially important for midline approaches to nasion encephalocele, midline trauma, surgery for hypertelorism as well as midline approaches to anterior skull base lesions. The medial canthal tendon is of primary importance in anchoring the eyelid medially in a cosmetic and functional fashion. This review will summarize the anatomic features of the medial canthus and its surrounding structures, including vascular and muscular components. The intimate relationship of the three components of the medial canthal tendon to the nasal lacrimal apparatus is emphasized. Techniques to prevent injury as well as to repair abnormalities in this area will be discussed.

Orbital hypertelorism

Excessive distance between the orbits is only one manifestation of a complex deformity that affects several skeletal and soft-tissue structures. This article discusses the classification, preoperative planning, and surgical procedures used in the reconstruction of orbital hypertelorism.

Unsuccessful consequence of optic canal decompression for a case of craniometaphyseal dysplasia

We have described a case of craniometaphyseal dysplasia in which decompression of bilateral optic canals for treatment of threatened damage of the optic nerve resulted in bilateral visual loss. We speculate that a specific mechanism exists whereby decompression of the optic canal can cause blindness.

Frontonasal and craniofrontonasal dysplasia: preoperative quantitative description of the cranio-orbito-zygomatic region based on computed and conventional tomography

The unoperated crano-orbito-zygomatic complex of 18 children (mean 4.7 years) with frontonasal dysplasia (FND) and 12 children (mean 1.1 years) with crainofrontonasal dysplasia (CFND) was quantified by 15 standard measurements performed on either computed tomography scans or facial tomograms. The results were compared with age-matched control values. In the FND group, the mean anterior interorbital and mid-interorbital distances were significantly increased at 148% and 118% of normal, and in the CFND patients, at 177% and 140% of normal. Excessive medial orbital wall protrusion (mean, 145% of normal in FND and 177% in CFND), shortened zygomatic arch lengths (mean, 94% of normal in FND and 91% in CFND), and reduced cephalic lengths (mean, 96% of normal in FND and 83% in CFND) were all observed. An expanded interzygomatic buttress distance was documented only in the CFND group, at 11% of normal. The clinical presentation of craniofacial deformities such as FND and CFND can be objectively described by a numerical analysis of the bony pathology.

Surgical correction of hypertelorism. Report of 40 cases

Forty patients with hypertelorism seen in the past 16 years were reviewed retrospectively. Combined intra- and extracranial surgical approach was used for 37 severe and moderate cases and subcranial approach (U-osteotomy) for 3 moderate cases. Gratifying results were obtained in patients with different types of hypertelorism by a multidisciplinary team. Complications were also reviewed. Of the 37 cases of intra- and extracranial corrections, 1 died, 4 had cerebrospinal fluid leakage and 4 had keratitis. No seizure, cerebral edema, meningitis, blindness, and ptosis occurred in this series. The average age was 13 years and two months. Operating time averaged 6 hours and 50 minutes. Hypertelorism was mostly attributable to craniofacial cleft, craniosynostosis, frontoethmoidal meningoencephalocele, frontonasal fibrous dysplasia, and trauma. Satisfactory esthetic appearance was achieved in most of the cases.

[Reconstructive surgery in the area of the orbit]

Craniofacial techniques have dramatically improved the possibilities for reconstructive procedures in the orbital region. Indications occur in acute or delayed fracture repair as well as in tumor surgery and in the correction of congenital malformations.

Enophthalmos following orbital transposition for craniofacial malformations

This is a retrospective study of the frequency and factors that portend enophthalmos following orbital osteotomies and transposition for craniofacial malformations. Clinically obvious postoperative enophthalmos (POE) was noted in 23 (37.7 percent) of 61 patients undergoing such procedures. Postoperative enophthalmos was observed in 86 percent of Apert patients who had combined anteromedial orbital transposition and in 48 percent of patients with hypertelorbitism who had standard 360-degree osteotomies. In contrast, the incidence of postoperative enophthalmos was 21 percent following frontofacial (monobloc) or subcranial (Le Fort III) advancement. Postoperative enophthalmos also correlated with the occurrence of orbital fracture/fragmentation and with disruption of the periorbita. This study underscores the importance of establishing the correct relationship of the globe to the orbital rim (euophthalmos) while maintaining the spatial position of the eye, especially its anterior projection. Postoperative enophthalmos can be prevented by inserting bone grafts into orbital osteotomy gaps, correcting orbital volume/morphology following floor or wall outfracture/fragmentation, and preserving the periorbital supporting system.

An objective assessment of treatment for orbital hypertelorism

A retrospective statistical analysis of orbital hypertelorism correction was performed by comparing the preoperative and postoperative intercanthal distances of these patients with published age-matched normal values. Forty-five patients who had undergone surgery over a 15-year period with an average follow-up of 5 years (6 months to 14 years) were evaluated. Comparison of age-normalized preoperative and postoperative intercanthal distances revealed a significant difference for orbital hypertelorism patients as a group (p < 0.0001), patients with clefts (p < 0.0001), patients with nasoencephalocele (p < 0.01), and patients with frontonasal dysplasia (p < 0.05), but not for those patients with craniofacial dysostosis (p < 0.20). Multiple analyses of variance revealed a significant interaction existing between the extent of preoperative deformity and the cause of hypertelorism for both the postoperative deformity and the total amount of correction achieved, but not for the type of surgery or for the age at which the surgery was performed.

Mid-facial sensation following craniofacial surgery

During mid-face advancement and correction of orbital dystopia, the infraorbital nerves are always stretched and displaced by the orbital floor osteotomies and bone displacement, and are at risk of damage. We have found no published work that has investigated the function of the infraorbital nerves following elective craniofacial procedures. In this study the cheek sensation and tooth sensibility in 20 patients who have had either mid-face advancement or correction of orbital dystopia was assessed. The function of the infraorbital nerve is largely undisturbed by the osteotomies and bone displacement performed during these procedures. A small proportion of patients could not feel cold in their anterior maxillary teeth, suggesting that there is damage to the anterior superior alveolar nerve branch of the infraorbital nerve.

[Surgical correction of 34 patients with hypertelorism]

In 34 patients with hypertelorism aged on the average 12.6 years, 24 underwent intracranial surgery (combined intra- and extracranial approach), 2 (moderate) U-osteotomy (subcranial approach), and 8 (mild) canthoplasties. Improved results were obtained in the patients with various types of hypertelorism. The complications were reviewed. Of the 24 patients undergone intracranial surgery, one died, 4 had cerebrospinal fluid leakage, and 4 had keratitis. No seizure, cerebral edema, meningitis, blindness, and ptosis were observed in these patients. Average blood loss was 72% of blood volume. Average duration of surgery was 7.5 hours. The causes of hypertelorism such as craniofacial cleft, craniosynostosis, frontoethmoidal meningoencephalocele, frontonasal fibrous dysplasia, and trauma were also discussed. Satisfactory appearance was seen in most of the patients.

[Neurosurgical problems in craniofacial surgery for maxillofacial and ENT diseases]

From June 1978 to June 1990, 48 patients (34 patients with skull base tumors and 14 with congenital hyperterolism) were treated by combined craniofacial surgery. Cranial approaches were performed through the anterior fossa in 7 patients, middle fossa in 19, posterior fossa in 1, both anterior and middle fossa in 6, middle and posterior fossae in 1 and bilateral anterior fossae in 14. Neurosurgical problems were discussed.

Soft tissue expansion in the management of the rare craniofacial clefts

Management of the rare craniofacial clefts requires correction of both the soft tissue and skeletal hypoplasia. Tissue expansion of adjacent and distant soft tissue has been used to reconstruct these facial clefts with like quality tissue. Additionally, such soft tissue expansion permits tension free reconstruction of the skeletal clefts by osteotomy and bone graft.

The skeletal treatment of orbital hypertelorism

Orbital hypertelorism, strictly defined as an increase in bony interorbital distance, is not itself an isolated syndrome, but is instead an anomaly that may occur as either part of a syndrome or malformation sequence. Evaluation of orbital hypertelorism and the various anomalies that accompany it is best performed by a multidisciplinary craniofacial team. The timing of surgery involves considerations of multiple variables, but when performed can offer marked cosmetic improvements. Equally important as the skeletal surgery is correction of the associated soft-tissue problems.

High-energy orbital dislocations: the possibility of traumatic hypertelorbitism

In a 4-year period from 1983 to 1987, 7160 patients with blunt injuries were admitted to the Maryland Institute of Emergency Medical Services Systems Shock Trauma Center. Facial injuries occurred in 10 percent of this population. High-energy fractures (characterized by computed tomography) were seen in approximately 10 percent of these patients. In this high-energy group, five cases of high-energy orbital dislocations, some representing examples of traumatic hypertelorbitism, were observed. They represent 1.5 percent of the 342 midface fractures observed and 4.8 percent of the naso-orbital ethmoid fractures observed (105 patients). One additional patient is described who was seen at the UCLA Medical Center for late repair of the condition. High-energy impacts of the upper midface created fractures of both orbits, zygomas, and nasoethmoidal regions permitting lateral transposition, enlargement, and divergence of the orbits. Interorbital, intercanthal, and interpupillary distances were increased, criteria that confirm the diagnosis of hypertelorbitism. Fifty percent of the patients were bilaterally blind, and one patient sustained unilateral blindness.

Frontoethmoidal meningoencephalocele. A one-stage correction, reconstruction, and plating by means of the micro system

This case report on one stage surgical treatment of meningoencephalocele offers the opportunity for a revision of the most recent trends expressed by other authors on this topic. Surgical technique involved a system of rigid fixations by means of microplates which, according to our experience in other cases, is particularly advisable in pediatric age. We find that the simultaneous utilization of calvarial bone grafts facilitates a better reconstruction of the cranial base, and also offers greater stability in results.

Orbital dystopia: attempts to evaluate the results of surgery

This study has shown that surgery for hypertelorism or vertical orbital dystopia gives very satisfying results overall to the patients and their families and leads to a modest but highly significant objective improvement in appearance after surgery, as perceived by panels of laymen or hospital staff not known to the patients. The complexities of the methodology of panel assessments of appearance are discussed. The results of this study confirm the need to go beyond our traditional methods of assessing surgical outcome simply within our specialty.

Geometrical planning for the correction of orbital hypertelorism

Orbital hypertelorism may be associated with a variety of deformities affecting several elements of the craniofacial skeleton. Shortness of the central portion of the face represented by a wide, short nose and anterior open bite is frequently combined with the exaggerated interorbital distance. With the mobilization of the two halves of the face it is possible to approximate the orbits, simultaneously elongating the center of the face and normalizing the maxillary alveolar ridge. A technique is described to plan the operation geometrically in order to predict accurately the skeletal correction, the change of the inclination of the eye slant, and the modification of the axis of the teeth.

Computerized tomographic analysis of orbital hypertelorism repair: spatial relationship of the globe and the bony orbit

Computerized tomographic scans provide a new means of evaluating the spatial and geometric relationships between the movement of the bony orbit and its soft tissue contents (the globe and extraocular muscles) [1, 12]. Preoperative and postoperative computerized tomographic scans were analyzed in four patients to explore these relationships. Measurement of the changes in distance between the globes correlated most closely with the change in the distance between the lateral orbital walls; resection of medial (inter-orbital) bone provides space into which the globe is translocated. The medial rectus muscle may be bowed across the medial wall osteotomy line, creating a functional shortening of the muscle; this finding may explain the esotropia that is commonly seen after this procedure [2, 3]. These observations should have a direct impact on the understanding and planning of orbital hypertelorism correction.

Hypertelorism correction in the young child

This series reports on 20 patients who underwent orbital hypertelorism correction under 5.3 years of age (average age 3.9 years). The patients were followed an average of 5 years, and six patients were followed in excess of 7 years with clinical and cephalometric parameters. The study demonstrated that the procedure could be safely performed at this age and was aesthetically desirable. There was minimal clinical or cephalometric evidence of skeletal orbital relapse except in three patients, for whom individual explanations are given. During the period of postoperative study, nasomaxillary growth and development proceeded as expected, except in those patients with associated clefting. All patients demonstrated increased cranial width measurements preoperatively and postoperatively, but bigonial and bimastoid measurements were generally within normal range. Excessive resection of nasoglabellar skin at the time of hypertelorism correction appeared to adversely affect nasal development.

Subcranial approach for the correction of hypertelorism

The subcranial approach for the osteotomy of the skull base and orbital roof in cases with hypertelorism is described. Advancement of the fronto-orbital segments is performed, avoiding the transfrontal procedure, thus making frontal lobe retraction unnecessary. The advantages of this method are pointed out.

The psychosocial adjustment of pediatric craniofacial patients after surgery

The postsurgical psychological status of 25 craniofacial patients, 6 through 16 years of age, was studied using self, teacher, and parent report measures. In contrast to earlier reports of more positive adjustment following corrective surgery, the present study identified several concerns for craniofacial patients, including low self-esteem, impaired peer relationships, and greater dependency on significant adults. Problems were more clearly identified using projective techniques rather than self-report measures. The findings suggest that many children having craniofacial surgery should have supportive psychotherapeutic services. Variables were explored relative to psychosocial functioning. Although few significant correlations were demonstrated, positive psychological adjustment was found to be related to greater physical attractiveness, lower parental stress, and younger age.

Correction of orbital hypertelorism in Asian patients

In this article, correction of orbital hypertelorism in Oriental patients is summarized. An orbital osteotomy is currently used to correct an abnormally wide interorbital distance. At present, associated deformities such as a short nose and a depression deformity in the temporal region following orbital osteotomy can be partially corrected. In Oriental patients, the Mongolian fold can be enhanced after correction of orbital hypertelorism. This fold can be easily corrected by epicantoplasty.

Projection geometry and stress-reduction techniques in craniofacial surgery

Since 1981, we have been able to modify the mathematical patterns of projection geometry to reshape the skull in craniofacial surgery. Unlike burring, morcellization, rotation, and plate switching, this technique actually changes the shape of individual sections of the skull by changing their radius of curvature. The technique is an adaptation of the principles used by engineers to build complex structures such as ships' hulls, airfoils, and domes. The result is a rigid form of the desired shape that becomes permanent with healing. This has several advantages: 1. An increase in the level of safety of craniofacial procedures for remodeling the skull. This is so because there is no need to dissect normal areas as in the standard plate-switching techniques. 2. Decreased operating room time. 3. An increased range of surgical manipulations. No longer is the surgeon limited to the shape of the material present. 4. Relief of edge pressure on the frontal lobes during scalp closure. 5. Creation of a solid bony form over which the pericranial scalp flap can be draped to form new layers of bone.