ORBITAL GROWTH AFTER UNILATERAL ENUCLEATION IN CHILDHOOD

The Versatility of the Free Vastus Lateralis Muscle Flap: Orbital Reconstruction After Removal of Complex Vascular Malformation in a Pediatric Patient

Introduction: Vascular orbital lesions in pediatric population represent a demanding therapeutic challenge which requires a multidisciplinary team. In severe cases, orbital enucleation can be considered. Surgical management of enucleated orbital region in children, differently from the adults, represents a challenging procedure owing to the intrinsic relation between volume replacement and normal orbital growth. Many reconstructive options have been proposed, and many donor sites have been utilized for this purpose but each one have demonstrated potential disadvantages. Despite its well-known versatility, no report of the vastus lateralis free flap in children requiring orbital reconstruction exists in literature. Herein, we propose this surgical strategy as a valid option for the reconstruction of an extended orbital defect in a pediatric patient suffering from a mixed type of vascular malformation. Material and Methods: A patient was referred from a foreign country with an unclear medical history, presenting exorbitism and exophthalmos, proptosis of the eyeball, visus 4/10, and limited ocular motility. We made clinical-instrumental investigations with a diagnosis of complex vascular malformation. It expanded in intraorbital and retrorbital space with bulb anterior dislocation and optic nerve involvement. We performed an emptying of the orbital content via transconjunctival and via coronal incision with eyelid preservation. A free vastus lateralis muscle flap was used for reconstruction, filling the orbital cavity. We anastomosed the flap on the superficial temporal artery. An ocular conformator was then positioned. Results: We report the result at 12 months, showing a good orbital rehabilitation with an adequate prosthetic cavity, a good recovery of volume and facial symmetry, guaranteeing balanced orbital and periorbital growth. There were no major or minor complications associated with the procedure. Discussion: The reconstruction of the orbit remains a "surgical challenge" both in adults, whose goal is the restoration of volume, adequate symmetry and facial esthetics, and children, in which correcting the asymmetry has the additional objective to balance orbital growth. Many reconstructive techniques have been proposed, including the use of free flaps. The versatility of the free vastus lateralis muscle flap is well-known. It offers adequate amount of tissue with minimal morbidity to the donor site, provides a long pedicle, gives the possibility of simultaneous work in a double team, and has a constant anatomy and a safe and rapid dissection. There are no descriptions of its use for pediatric orbital reconstructions. Conclusions: In our opinion, the free vastus lateralis flap should be included as one of the best option for orbital pediatric reconstruction after enucleation.

Outcomes of enucleation and porous polyethylene orbital implant insertion in patients with paediatric retinoblastoma: a long-term follow-up study

BACKGROUND/AIMS

To report the long-term outcomes of enucleation and insertion of porous polyethylene (PP) orbital implant according to the evolving surgical techniques and implant in patients with paediatric retinoblastoma .

METHODS

Patients with paediatric retinoblastoma who underwent enucleation and PP implant insertion from December 1998 to December 2014 were retrospectively reviewed and divided into four groups: group A, classic enucleation +PP implant; group B, enucleation +PP implant +anterior closure of the posterior Tenon's (ACPT) capsule; group C, enucleation +PP implant +free orbital fat graft +ACPT and group D, enucleation +smooth surface tunnel PP implant +ACPT. Survival analysis of implant exposure and eyelid malpositions was performed.

RESULTS

One hundred and ninety-eight eyes of 196 patients were included. The median follow-up period was 13.0 years (range, 5.0-21.1). A 20 mm implant was inserted for 149 eyes (75.3%). The 10-year exposure-free survival probabilities were 44.6% in group A, 96.4% in group B, 97.4% in group C and 97.7% in group D. ACPT was associated with significant reduction in implant exposure (p<0.001). The most common eyelid malposition was upper eyelid ptosis (24.2%). The eyelid malposition-free survival probability did not differ among the four groups. However, the insertion of a 20 mm implant was associated with significant reduction in upper eyelid ptosis and lower eyelid entropion (p=0.004 and 0.038, respectively).

CONCLUSIONS

The long-term postenucleation implant exposure was rare after PP implant insertion and ACPT, even with a 20 mm-diameter implant. A larger implant can be beneficial in long-term prevention of eyelid malposition.

Measurement of orbital volume after enucleation and orbital implantation

Introduction

This article reports experience relating to the measurement of orbital volume by means of cone beam computed tomography (CBCT) and Cranioviewer program software in patients who have undergone enucleation and orbital implantation.

Patients and Methods

CBCT scans were made in 30 cases, 10 of which were later excluded because of various technical problems. The study group therefore consisted of 20 patients (8 men and 12 women). The longest follow-up time was 7 years, and the shortest was 1 year. In all 20 cases, the orbital volume was measured with Cranioviewer orbital program software. Slices were made in the ventrodorsal direction at 4.8 mm intervals in the frontal plane, in both bony orbits (both that containing the orbital implant and the healthy one). Similar measurements were made in 20 patients with various dental problems. CBCT scans were recorded for the facial region of the skull, containing the orbital region. The Cranioviewer program can colour the area of the slices red, and it automatically measures the area in mm.

Results

In 5 of the 20 cases, the first 4 or all 5 slices revealed that the volume of the operated orbit was significantly smaller than that of the healthy orbit, in 12 cases only from 1 to 3 of the slices indicated such a significant difference, and in 3 cases no differences were observed between the orbits. In the control group of patients with various dental problems, there was no significant difference between the two healthy orbits. The accuracy of the volume measurements was assessed statistically by means of the paired samples t-test.

Summary

To date, no appropriate method is avaliable for exact measurement of the bony orbital volume, which would be of particular importance in orbital injury reconstruction. However, the use of CBCT scans and Cranioviewer orbital program software appears to offer a reliable method for the measurement of changes in orbital volume.

Followup of a Dog with an Intraocular Silicone Prosthesis Combined with an Extraocular Glass Prosthesis

Because of unpredictable corneal changes, evisceration and implantation of a silicone prosthesis does not always lead to a satisfying cosmetic result. This paper describes the use of an intraocular silicone prosthesis in combination with an extraocular glass prosthesis and shows a followup of two and a half years in a nonexperimental study. An intraocular silicone prosthesis was implanted after evisceration of the left eye in a five-month-old Bernese mountain dog. A glass prosthesis was fitted four weeks after evisceration. Two and a half years after the operation, the dog is in good health and free of medication. No short-term or long-term complications were seen. The owners do not have trouble with handling the glass prosthesis. The combination of both prostheses shows a perfect solution to retrieve a normal looking and moving eye after evisceration.

Perspective on Orbital Enucleation Implants

The philosophy and design of orbital enucleation implants have evolved significantly over the past 50 years. Animal studies and improved imaging techniques have changed our understanding about the physiology and anatomy of the post-enucleation orbit. Changes in implant design and biomaterials have reduced complication rates. It is our impression that for many ophthalmic professionals in training, the rational behind the current thinking in implant design and biomaterials is unclear. This is in part related to the older literature on orbital enucleation implants, which is scattered and at times contradictory. This review aims to present the historical information in a coherent and concise form; provide evidence based review of changes in the practice patterns of enucleation; identify areas of continuing controversy; and highlight gaps in the scientific literature about orbital implants, in particular, the poor understanding of implant and prosthesis motility.

Evaluation of an integrated orbital tissue expander in an anophthalmic feline model

PURPOSE

To evaluate the anatomical effects and tissue biocompatibility in a feline model of an integrated orbital tissue expander (OTE) designed to stimulate bone growth in an anophthalmic socket.

DESIGN

An animal study was performed in cats to assess orbital bone growth with and without an OTE.

METHODS

The OTE is an inflatable (0.5 to >6.0 cm(3)) polymeric globe sliding on a titanium T plate secured to the lateral orbital rim with screws. Eight cats had left eye enucleation at age two weeks, with five orbits receiving an OTE and the remaining three serving as nonimplanted controls. Serial transconjunctival implant inflation was performed by injecting normal saline solution into the OTE to a final volume of 3.5 ml. Serial computed tomographic scans were obtained to assess socket growth. All eight cats were euthanized at 18 weeks and dry skulls prepared. The effective orbital volume was measured by inflating an OTE in the orbit of a dry skull until it filled the cavity completely.

RESULTS

Three cats periodically scratched open the tarsorrhaphy and conjunctiva to rupture the OTE, which resulted in implant exchanges. At 18 weeks, the OTE expanded orbital volume was approximately 18% smaller than the normal contralateral side. In the control animals, the anophthalmic orbital volume was approximately 66% smaller than the contralateral orbit. Histopathology of orbital tissues showed no evidence of foreign body reaction.

CONCLUSIONS

This proof-of-concept pilot study demonstrated implant efficacy in cats, and no implant-related adverse effects were observed. OTE has the potential to stimulate bone growth in human anophthalmic orbits.

Abnormalities of orbital volume

New information on the physiopathology and treatment of orbital volumes pathologies is described: 1) In post-enucleation or evisceration socket syndrome placing of synthetic material (HA-TCP) directly in the intraconal orbital fat can correct most of the symptoms. However the best approach is to prevent orbital volume deficiencies during first surgery using an implant large enough to allow a future prosthesis of a volume less than 2 mL. New procedures for placing the implant after enucleation or evisceration are described. 2) In proptosis related to Graves' orbitopathy relative indications are given for orbital decompression by removal of fat or bone.

Bony orbital development after early enucleation in humans

AIM

To analyse the extent of bony orbital volume reduction after enucleation in humans.

METHODS

Volumetric studies on bony orbital volumes based on three dimensional reconstructions acquired from high resolution computed tomograph (CT) scans were performed in 29 patients with acquired anophthalmia and four patients before enucleation (controls). Eight patients (follow up 25-52 years) were enucleated in childhood aged between 0.4 and 8 years (group I), 21 in adulthood aged between 15 and 53 years. Fifteen of these patients (group IIa) had long standing anophthalmia (follow up 7-53 years), six patients (group IIb) were enucleated 9 months to 4 years before CT.

RESULTS

Bony orbital volumes were reduced in all patients with long standing anophthalmia. The median percentage reduction in enucleated orbits was 7.0% in group I, 3.8% in group IIa, and 1.9% in group IIb. In patients with long standing anophthalmia (I and IIa) the reductions were statistically significantly different (p <0.01) from zero. There was some evidence of a correlation between orbital volume reduction and age at enucleation (rho = 0.36, p = 0.09, Spearman rank correlation coefficient) and a statistically significant correlation between volume reduction and time interval since enucleation (rho = -0.5, p = 0.003). Clinically none of the patients showed significant facial asymmetry.

CONCLUSIONS

These data provide strong evidence that enucleation both in children and adults is associated with a reduction of bony orbital volume and that this decrease in volume is associated with increasing time. However, the reduction is smaller than generally assumed and does not cause obvious facial asymmetry. It is more related to the time interval since enucleation than the age at enucleation, which makes a mechanism of volume adaptation more likely than just retardation of growth.

The effect of buphthalmos on orbital growth in early childhood: increased orbital soft tissue volume strongly correlates with increased orbital volume

PURPOSE

Our purpose was to evaluate the effect of increased orbital soft tissue volume on orbital growth.

METHOD

Patients with unilateral or significantly asymmetric bilateral buphthalmos as determined by axial computed tomography scan were recruited. Volumetric determinations of the bony orbit with use of axial 1.5 mm sections on computed tomography were undertaken. Statistical analysis of the paired ocular length measurement and bony orbital volume measurements for each patient were performed.

RESULTS

Eight patients (mean age 41 months) with a 15% or greater difference in axial length were enrolled. The mean axial length of the buphthalmic globes was 23% greater than that of the contralateral globes. Orbits harboring a buphthalmic globe had an orbital volume 11% greater than on the contralateral side.

CONCLUSION

Increased orbital soft tissue volume as evidenced by buphthalmos was significantly associated with enlarged bony orbital volume. This indicates that soft tissue volume is a determinant of orbital volume and suggests that orbital tissue expanders might enhance bony development in patients with anophthalmos or microphthalmos and after early enucleation.