Effects of hyperbaric oxygen therapy on hydroxyapatite orbital implant vascularization in rabbits.

PURPOSE: To deterrmine if hyperbaric oxygen therapy affects the rate of hydroxyapatite orbital implant vascularization in normal rabbit orbits. METHODS: We performed a randomized comparative experimental pilot study involving 6 rabbits. All rabbits were enucleated and implanted with hydroxyapatite orbital spheres. The animals were randomized for enucleation of the right or left eye and for treatment or nontreatment (control) with hyperbaric oxygen. The implants were removed after 3 weeks of treatment and histologically examined for fibrovascular ingrowth, inflammation, and multinucleated giant cells. Each parameter was graded on a numeric scale and analyzed. RESULTS: Hyperbaric oxygen therapy did not increase implant vascularization compared with nontreatment implants. Although treated implants had less central fibrovascular maturity compared with control implants, the difference was not statistically significant (p < 0.055). There was no significant difference in inflammation or the number of multinucleated giant cells between treated and control implants. CONCLUSIONS: In this pilot study, hyperbaric oxygen therapy did not increase hydroxyapatite vascular ingrowth and possibly delayed fibrovascular maturation in normal sockets. Further studies with more subject numbers are needed to confirm these conclusions. The effect of hyperbaric oxygen therapy in vascularly compromised sockets also needs to be determined.

The risk of diplopia following orbital floor and medial wall decompression in subtypes of ophthalmic Graves' disease.

We preoperatively divided 58 ophthalmic Graves' disease patients into types I and II categories before two-wall orbital decompression. Type I classification was given to patients who had no diplopia and essentially normal versions. Type II classification was assigned to patients with restrictive motility loss and diplopia within 20 degrees of the primary position. Ocular motility was assessed before and after two-wall orbital decompression. Only one of 25 type I patients (4%) experienced diplopia after orbital decompression, while seven of 14 (50%) (p = 0.001) type II patients without preoperative primary-position diplopia had primary diplopia postoperatively. Of 12 type II patients who had preoperative primary-position diplopia, esotropia increased by an average of 12.4 diopters postoperatively. Vertical deviation increased an average of 13.4 diopters for 10 patients who underwent unilateral two-wall decompression. The likelihood of new or worsening diplopia in all type II patients following decompression was 22 of 36 (61%). We conclude that adverse motility change following two-wall orbital decompression is rare in type I disease patients, but it occurs 61% of the time in type II disease patients. Predicting preoperatively which patients are likely to develop adverse motility change and diplopia may help clarify indications and risks of orbital decompression surgery in patients with ophthalmic Graves' disease.

The effect of maturation on the ability to stimulate orbital growth using tissue expanders in the anophthalmic cat orbit.

Tissue expanders were used to stimulate orbital growth at different stages of maturity in the immature anophthalmic cat orbit. Twelve cats had the right globe enucleated at 2 weeks of age and tissue expanders implanted in the orbit. The cats were randomized into four groups (A, B, C, and D). The tissue expanders remained in the nonexpanded state for a preassigned length of time. Orbital volume was determined on each cat using computed tomography (CT) immediately prior to expansion of the implant. Expansion began at age 10 weeks for group A, 15 weeks for group B, and 25 weeks for group C and involved 0.7 cc injections of saline at 2-week intervals until a final volume of 4.5 cc was obtained. Group D remained as a nonexpansion control group. Four to 5 weeks after expansion was completed, a second orbital volume CT was obtained on each animal and compared with the pre-expansion CT. The right orbits of group A, had pre-expansion (week 10) orbital hypoplasia with a volume 26.2% smaller than the left control orbits. Postexpansion (week 25), the right orbital hypoplasia had decreased to a volume 10.3% less than the left control orbits. The right orbits of group B had pre-expansion (week 15) orbital hypoplasia with a volume 35.6% smaller than the left control orbits. Postexpansion (week 31), the right orbital hypoplasia had decreased to a volume 25.9% less than the left control orbits. The right orbits of group C had a preexpansion (week 25) orbital hypoplasia with a volume 39.8% smaller than the left control orbits. Postexpansion (week 41), the right orbital hypoplasia had decreased to a volume 29.3% less than the left control orbit. Tissue expanders, expanded in the hypoplastic immature cat orbit stimulated orbital growth and reversed orbital bony hypoplasia to varying degrees. The amount of growth stimulated was inversely proportional to the age at which expansion began. Orbital growth, stimulated by tissue expander expansion, was also demonstrated after the normal age of cat orbit maturation (weeks 28-30).

Efficacy of lateral canthotomy and cantholysis in orbital hemorrhage.

Emergent orbital decompression in tense orbital hemorrhage with compromised ophthalmic blood flow may be achieved with lateral canthotomy, defined as incision of the lateral canthal tendon, and cantholysis, defined as canthotomy combined with disinsertion of at least the inferior crus of the lateral canthal tendon. This study was performed to determine which procedure, canthotomy, canthal tendon disinsertion, or cantholysis, produced the largest reduction in intraocular pressure after simulated orbital hemorrhage in 10 closed ruminant orbits with retrobulbar injections of normal saline. Intraocular pressure (IOP) reductions were measured after canthotomy in five orbits, after lateral canthal tendon disinsertion in five orbits, and after completion of cantholysis in all 10 orbits. Canthotomy produced a mean IOP reduction of 14.2 mm Hg. Canthal tendon disinsertion (CTD) produced a mean IOP reduction of 19.2 mm Hg. Cantholysis produced a mean IOP reduction of 30.4 mm Hg, a significantly (p < 0.05) greater reduction in IOP than that produced by canthotomy or canthal tendon disinsertion alone. Cantholysis in acute orbital hemorrhage may produce significantly greater reduction in IOP, and thus in intraorbital pressure, and allow better perfusion of orbital tissues than either lateral canthotomy or CTD.

Traumatic chiasmal syndrome associated with midline basilar skull fractures.

We studied two young males who had visual field defects consistent with optic chiasmal injury after blunt frontal head trauma. One patient also had a unilateral optic neuropathy. Long-term follow-up disclosed complete bi-temporal hemianopsias in these patients. Both patients had midline basilar skull fractures that traversed the midclivus through the sella turcica floor, dorsum sellae, and sphenoid sinus. Magnetic resonance images did not identify intrachiasmal hemorrhage as the cause of the visual field defect. We believe this fracture pattern, in conjunction with the magnetic resonance image findings, suggests tearing of the optic chiasm on a microscopic, if not macroscopic, scale as the cause of the complete bitemporal hemianopsia.

Eccrine adenocarcinoma of the eyelid in a young patient.

Malignant eccrine adenocarcinoma of the lower eyelids is described in a 16-year-old girl. This rare tumor has previously been reported only in males, whose average age was 64 years. Our patient remains tumor free 7 years after wide resection of the eyelid and reconstruction.

The association of cigarette smoking with clinical subtypes of ophthalmic Graves' disease.

We retrospectively reviewed the smoking habits of 124 patients with Graves' ophthalmopathy. We divided these patients into those without restrictive myopathy (type I) and those with restrictive myopathy (type II). Sixty-three percent of type I and 83% of type II patients were smokers at the time of diagnosis. The incidence of smoking in an age- and gender-matched randomly selected control population in the same geographic area was 30% for controls matched to our type I group and 26.6% for controls matched to our type II group. We believe smoking is an important factor in the development of both clinical subtypes of Graves' ophthalmopathy.

Extrusion rate of silicone spherical anophthalmic socket implants.

The most popular technique of placement of an anophthalmic spherical implant was first described by Frost and Lange in 1886, and has remained essentially unchanged since that time. That technique incorporates imbrication of recti muscles over an 18 mm spherical implant, and purse stringing of conjunctiva and Tenon's fascia in a single layered closure. The Frost-Lange technique has led to previously reported extrusion rates as high as 11.3%. The technique is also associated with superotemporal implant migration and poor prosthetic motility. Our technique modification includes suturing recti muscles independently to a 20 mm spherical implant reinforced with autogenous fascia or preserved sclera. We then close Tenon's fascia and conjunctiva independently as separate layers. The extrusion rate for our patients during a 10 year study period was 0.84% (1 of 119). We found no implant migration, no painful socket, and prosthetic motility was good. We recommend our technique modification to replace the traditional Frost-Lange technique.

Effects of radiation on the use of hydroxyapatite for orbital reconstruction in the rabbit.

The gross and histopathologic effects of external beam radiation on host response to subperiosteal implantation of dense hydroxyapatite (HA) blocks along the superior orbital rim was investigated, using the rabbit as an experimental model. Three study groups were employed: those with no radiation, those receiving 500 cGy, and those receiving 1,500 cGy. The hydroxyapatite blocks were surgically implanted 2 weeks after administration of the radiation. The pathologic specimens, including the HA block and the neighboring bone segment, were harvested and examined at either the fourth or 12th postsurgical week. There was essentially no inflammatory reaction stimulated by the implanted HA blocks, nor was there any evidence of abnormal bone remodeling in the underlying orbital rim segments. The most secure bonding between the HA block and bone was found in the specimens having received either 500 cGy or 1,500 cGy and harvested at 12 weeks. We conclude that HA serves as an acceptable bone graft substitute in areas previously treated with radiation. The various properties of HA are also reviewed.

Exposure rate of hydroxyapatite spheres in the anophthalmic socket: histopathologic correlation and comparison with silicone sphere implants.

We retrospectively reviewed enucleations and secondary anophthalmic socket sphere implantations for a 3 year period. We compared the incidence of exposure of hydroxyapatite implants to the incidence of exposure of silicone implants. We found that the incidence of hydroxyapatite exposure following enucleation was 3 of 27 (11.1%), and following secondary anophthalmic socket implantation was 3 of 32 (9.4%). The incidence of silicone sphere exposure following enucleation was 0 of 48 (0%), and following secondary implantation was 1 of 30 (3.3%). The difference in exposure rate between hydroxyapatite and silicone reached statistical significance in the enucleation group (p = 0.043) and in the combined enucleation and secondary implantation group (p = 0.033), but not in the secondary implantation group when considered separately. Osteoinduction and fibrovascular infiltration were found in all hydroxyapatite specimens examined histopathologically. In the exposed implants, liquefaction necrosis of the implant occurred. In the nonexposed implant, complete fibrovascular ingrowth was noted at 7 months. We believe that the hydroxyapatite anophthalmic sphere is associated with a higher incidence of exposure and postoperative inflammation when compared to silicone anophthalmic spheres. Patient selection and technique modification may reduce the incidence of hydroxyapatite implant exposure.

Spontaneous orbital subperiosteal hematomas in patients with liver disease.

Spontaneous orbital subperiosteal hematomas are rare entities. They are often associated with systemic coagulopathies. We present two cases of spontaneous orbital subperiosteal hematomas in patients with systemic coagulopathies resulting from liver disease. One patient was diagnosed with hepatitis B and had spontaneous resolution of the hematoma. Another patient had alcoholic cirrhosis and required an orbitotomy for drainage of a hematoma for compressive optic neuropathy. With the rising incidence of hepatitis B and the prevalence of alcoholic liver disease, it is important to include liver disease in the systemic evaluation of patients with spontaneous orbital subperiosteal hematomas.

Stimulation of orbital growth by the use of expandable implants in the anophthalmic cat orbit.

We evaluated the efficacy of expandable orbital implants to stimulate bone growth in the anophthalmic cat orbit. Eighteen cats unilaterally enucleated at 2 weeks of age received either expandable orbital implants (groups A1 and A2), solid silicone sphere implants of 12 mm or 8 mm (groups B1 and B2), or no implant (group C). Those cats with expandable implants (group A) had the implant size increased by 0.5 ml injections of saline at 2-week intervals starting at 8 weeks of age until a final volume of 4 cc was reached. Four of the expandable implants were found to be only partially inflated at 20 weeks and were subgrouped A2. At 20 weeks of age, the anophthalmic orbits with fully inflated expanders showed no significant difference in either orbital volume or orbital entrance area when compared with control orbits: volume (91.2%), area (95.7%) (p = 0.01). These same orbits also showed a significant increase in both orbital volume and orbital entrance area when compared with the growth obtained by any other group. These other groups showed growth, expressed as a percentage of normal growth, as follows: partially inflated implant: volume (63.0%), area (69.0%); 12-mm sphere implant: volume (57.0%), area (54.5%); 8-mm sphere implant: volume (46.5%), area (44.6%); no implant: volume (47.6%), area (43.6%) (p = 0.01). This study suggests that the use of expandable orbital implants stimulates bony growth in the immature cat orbit. Bony stimulation was proportional to volume implanted, and expandable orbital implants achieved maximum bony stimulation in the groups studied.

Operative complications of the transconjunctival inferior fornix approach.

The transconjunctival inferior fornix incision provides access to the floor, rim, lateral, and inferior medial walls of the orbit. Complications of this surgical approach to the orbit are known to be rare but heretofore have not been clearly defined. Over an 8-year period, in an estimated 1200 cases, the authors have encountered cicatricial entropion, lower eyelid retraction, canthal dehiscence, lower eyelid avulsion, canalicular laceration, buttonhole laceration of the lower eyelid, conjunctival chemosis, and lacrimal sac laceration. Attention to anatomic landmarks and sound surgical execution will prevent these complications in most patients.

Dermal-fat graft as a primary enucleation technique.

A retrospective study of 36 dermal-fat grafts was undertaken to determine the indications as a primary enucleation implant material. Twenty-two patients or 61% required a reoperation in a three-year follow-up period. Sixty-seven percent required secondary prosthetic revision. We do not recommend dermal-fat grafting for routine enucleation due to high reoperation rate and prosthetic revisions.

Pseudallescheria boydii (Petriellidium boydii) infection of the orbit.

A 10-year-old male developed a chronic orbital infection following penetrating trauma and retention of an orbital foreign body. Diagnosis of infection with Pseudallescheria boydii (Petriellidium boydii) was made by fungal smear and culture. Sensitivity tests indicated the organism was resistant to amphotericin B. Surgical debridement of the inferior orbit and removal of the foreign body was followed by a six-week course of intravenous miconazole. The patient has shown no signs of recurrence in a two-year follow-up period. To our knowledge, this is the first reported case of orbital infection with Pseudallescheria boydii, although the organism has been reported in cornea, ocular, and peri-orbital sinus infections.

Lateral canthal approach to repair of trimalar fractures of the zygoma.

Trimalar fractures of the zygoma create a fracture dislocation of the lateral and inferior orbital walls. These are frequently associated with orbital and ophthalmic injury. A surgical approach to trimalar fracture repair should provide adequate exposure to the orbit and flexibility in dealing with associated orbital trauma. Surgical techniques for repair of trimalar fractures are reviewed. A new technique is presented that provides optimal orbital exposure and minimizes facial incisions.

Improved prosthetic motility following enucleation.

Enucleation is the beginning of a long-term relationship between the ophthalmologist and the patient to provide a comfortable, cosmetically acceptable, anophthalmic socket. The ideal socket should have a low risk of implant extrusion, normal volume, and normal motility of the prosthesis. Aspheric motility implants provide good motility, but pressure points between implant and prosthesis may lead to discomfort or extrusion. Spherical volume implants minimize pressure between implant and prosthesis, but have been criticized for inability to transmit motility to the prosthesis. The authors describe a modification of the traditional sphere implant technique that provides improved motility, ease in prosthetic fitting, and a comfortable socket.

Recurrence of sebaceous carcinoma of the eyelid after radiation therapy.

Sebaceous carcinoma originating in the meibomian gland recurred in six patients (four women, 61, 68, 71, and 88 years old, and two men, 52 and 65 years old) who had undergone radiation therapy. The patients had received radiation dosages ranging from 3,300 to 11,900 rads. The tumors recurred two months to two years after treatment. All six patients then underwent surgical excision of the tumors and have remained tumor-free for follow-up periods of as long as 42 months. These data indicated that radiation therapy of sebaceous carcinoma of the eyelid should be considered palliative rather than curative.