Caso Clínico

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Advancement osteotomy of the orbital rim for the treatment
of severe endocrine exophthalmos

Osteotomía de avance del marco orbitario para el tratamiento del exoftalmos endocrino severo

 

F. Almeida¹, J. M. Eslava², E. Sánchez-Jáuregui¹, M. Pezzi¹, J. L. Martínez-Lage³

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Abstract: Thyroid-associated orbitopathy is a debilitating disease of the visual system that is characterized by changes in the softtissues of the orbit and periorbita as a result of an inflammatory process, or as a consequence of this, and related to systemic disorders of the thyroid gland. Apart from the aesthetic changes that arise, patients may also present persistent keratitis due to exposure, diplopia, retrobulbar pain, compression of the optic nerve and even blindness. Surgery represents the definitive treatment for exophthalmos in Graves' orbitopathy as improvements are shown in proptosis and vision. A decrease is also experienced in ocular symptomatology and there is minimal morbidity. We present the case of severe exophthalmos that was surgically operated on with an advancement osteotomy of the supero-, lateral- and infraorbital rim, with partial removal of two of the orbital walls with lipectomy. The aesthetic results and the relief of the ocular symptoms were satisfactory. Key words: Endocrine exophthalmos; Orbital decompression; Obitotomy.

Resumen: La orbitopatía tiroidea es una enfermedad debilitante del sistema visual caracterizada por presentar cambios en los tejidos blandos orbitarios y periorbitarios debidos a un proceso inflamatorio, o a la consecuencia del mismo, y que se relaciona con alteraciones sistémicas de la glándula tiroides. Aparte de las alteraciones estéticas que ocasiona, los pacientes pueden presentar queratitis de repetición por exposición, diplopia, dolor retrobulbar, compresión del nervio óptico e incluso ceguera. La cirugía constituye el tratamiento definitivo del exoftalmos en la orbitopatía de Graves, mejorando la proptosis y la visión, así como diminuyendo la sintomatología ocular, con una morbilidad mínima. Presentamos un caso de exoftalmos severo que fue intervenido mediante osteotomía y avance del marco orbitario superior, lateral e inferior, remoción parcial de dos paredes orbitarias y lipectomía. Los resultados estéticos y el alivio de la sintomatología ocular resultaron satisfactorios. Palabras clave: Exoftalmos endocrino; Descompresión orbitaria; Orbitotomía.

Recibido: 12-07-2004

Aceptado: 07-10-2004

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1 Médico Residente
2 Médico Adjunto
3 Jefe de Servicio
Servicio de Cirugía Oral y Maxilofacial.
Hospital Universitario Ramón y Cajal. Madrid, Madrid, España.

Correspondencia:
Fernando Almeida Parra
C/ Cardenal Marcelo Spinola 48, 17º C
28016 Madrid, España.
e-mail: f_almeida_parra@hotmail.com

 

Introduction

Thyroid-associated orbitopathy (TAO) represents the primary cause of orbital pathology¹ and it is the most common extrathyroidal manifestation in Graves' disease. It tends to appear in hyperthyroid patients, but it has also been described in euthyroid and hypothyroid patients and in Hashimoto's thyroiditis.² It is found more commonly in women that in men, with two peaks in incidence, which for women is between the ages of 40-44 and 60-64, and for men is between the ages of 45-49 and 65-69.³ Of the patients with Graves' disease, 80% have a subclinical or self-limited orbitopathy.⁴ In 33% of patients with TAO there is a family history positive for thyroid disease. The more serious forms of TAO are associated with older patients, diabetics and smokers. Not only is the disease related in smokers with a more aggressive presentation, but also with a lower response to treatment and with a longer duration.⁵

TAO is an autoimmune disease with an unknown etiology, having no direct relationship with the metabolic disorders caused by an overproduction of thyroid hormones. This is why TAO does not show any improvement following proper metabolic control, and why this disorder is found in euthyroid or hypothyroid patients, and in Hashimoto's thyroiditis. TAO may be accompanied by other autoimmune disease such as Myasthenia Gravis, Vitiligo, and Diabetis.⁴ TAO produces an increase in the volume of the extraocular muscles, and in the fat and connective tissue. The muscles and the fat are edematous as a result of the increased glycosaminoglycan deposits, as well as the increase in cellularity, especially of CD4 T lymphocytes, B lymphocytes and macrophages. An accepted pathogenic hypothesis is that the CD4 T recognize antigen that share the thyroid gland and orbit, and they secrete cytokines that stimulate the fibroblasts to synthesize and secrete glycosaminoglycans that attract liquid into the retroorbital, periorbital and muscular space, leading to proptosis.⁶ The cell triggering the autoimmune response in TAO is unknown, although recent studies indicate that it could be the preadipocyte fibroblast, that under stimulation can result in adipose differentiation, leading to an increase in orbital fat. The inflammation of orbital tissues (fat and muscle) leads to discomfort, a sensation of orbital pressure, watery eyes, photophobia, stinging and palpebral and conjunctival inflammation. The evolution of the process leads to exophthalmos, alterations in ocular motility, fibrosis, venous congestion, diplopia, apex compression and optical neuropathy.⁷

TAO treatment depends on the phase the disease is in - inactive, or active. If in the active or inflammatory stage (it has started recently, the disease is progressive, there is pain or a sensation in the retrobulbar, pain on moving the eyes, worsening in the morning, palpebral and/or conjunctival inflammation) the treatment will consist in using corticoids, immunotherapy and/or radiotherapy. Corticoids are useful, as orbital soft tissue inflammation diminishes in practically all patients, and in a third of them ocular movement is improved. However, it cannot be used as treatment in the long term due to its systemic effects, and because the symptoms recur when it is stopped. Radiotherapy improves orbital congestion, as it has an anti-inflammatory effect leading to the destruction of T lymphocyte colonies. Immunosupressants are reserved for those cases in which corticoids are not used (if there is a poor response to treatment with the latter, and for diabetics, gastric ulcers, etc).⁷

In the inactive phase and non-inflammatory phase (there are no signs nor symptoms of inflammation, the disease has not flourished, and if there is an active change in response to treatment) surgical treatment can be opted for, as there are better results regarding the reduction of proptosis and the clinical than with steroid and/or radiotherapy treatment.⁸ Orbital decompression is the essential cornerstone in surgical TAO treatment, and it is the most effective method for compressive neuropathy at an orbital apex level.

The procedure of choice - what is usually carried out - is the partial elimination of the medial and lateral walls with lipectomy, but in severe cases (with Hertel values >25 mm) the treatment consists in the partial remodeling of the lateral wall and floor with lipectomy in association with an advancement osteotomy of the supra-, lateral- and infraorbital rim.

Clinical case

A 46 year-old female was referred to the Oral and Maxillofacial Surgery Unit by the Ophthalmology Unit for the evaluation and treatment of the exophthalmos she was experiencing. Her personal history was remarkable for arterial hypertension, morbid obesity and an allergy to egg yolk. In 1980 she was diagnosed with hyperthyroidism, caused by Graves- Baselow disease, and two years later she underwent surgery. A subtotal thyroidectomy was carried out and treatment with Levothyroxine 50 mg per day was given. In 1999 she attended the Ophthalmology Unit and reported a slow but progressive worsening of the exophthalmos, as well as signs and symptoms of keratitis. After treatment with megadoses of steroids and after radiotherapy had been rejected, she was operated on by our Unit and surgical decompression was carried out (medial wall and floor) of the left eye using a subciliary approach. In March 2002 a total thyroidectomy was carried out. In June 2003 she came to our Unit, with severe palpebral retraction, which was more accentuated in the external third or temple side of the upper lid; the area of the upper corneal limbus was uncovered, and part of the sclera was exposed. Hypertrophy of the suborbital fat was observed in the subciliary region of the lower lid (Fig. 1).

The exophthalmos was obviously bilateral. The patient complained of not being able to read for long, of tiredness and discomfort, and symptoms of ocular motility. The disease was in a non-inflammatory phase; there was no severe keratitis, hyperemia, chemosis of the conjunctiva or diplopia (Fig. 2).

The orbital CT scan showed exophthalmos, muscular thickening, an increase in orbital fat and a straightening of the optic nerve. With regard to NMR, this has the advantage of showing bony detail, which is of great value on planning surgical procedures of decompression (Fig. 3). The NMR showed exophthalmos, with severe muscular thickening and enlargement of the ventral portion and fatty tissues (Fig. 4).

In view of the background described, the clinical features and imaging tests, surgical treatment was decided on with partial remodeling of the lateral wall and orbital floor, together with lipectomy and an osteotomy for advancing the supra-, lateral- and infraorbital rim. A bicoronal approach was carried out, with a subgaleal flap approximately 2 cm long from the supraorbital border where an incision was made into the periosteum that was continued to the orbit through the supraorbital plane. The anterior portion of the temporalis muscle was freed of its insertion in order to allow better access to the lateral orbital wall. The approach was completed with a bilateral subciliary incision that allowed access to the infraorbital rim and to the medial area of the orbital floor.

A bilateral osteotomy was carried out - an orbitotomy - of the supra-, lateral- and infraorbital rim that was advanced 8 mm with regard to its original position. Osteosynthesis was carried out with 2.0 miniplates (Fig. 5). The lateral orbital wall was then eliminated, together with the medial and lateral part of the floor while avoiding the infraorbital nerve path. Incisions into the periorbita and the lipectomy were performed following removal of periorbital fat.

A subgaleal aspiration drain was placed and removed 48 hours later. A temporal tarsorrhaphy (Frost suture) was maintained for the first 48 hours. After 72 hours the patient had an intense pain in the back of her left leg that was diagnosed as a gemellus lacus thrombosis and treated with heparin. The subciliary suturing was removed 5 days later and the coronal 10 days later.

Results

This was a patient with a 22-year history of hyperthyroidism that had been in a euthyroid state for six months before the surgery. She had a slow but progressively evolving exophthalmos that was producing symptoms and ocular lesions, as well as considerable aesthetic sequelae. Surgical treatment (thyroidectomy) and corticotherapy had not achieved the results expected.

Although at the time the disease was in an inactive or non-inflammatory stage, the patient reported bouts of ophthalmologic symptoms with keratopathy, chemosis, hyperemia and chronic conjunctivitis. When the surgery was performed the patient was experiencing watery eyes, photophobia and foreign body sensation.

Following the surgery, the patient experienced considerable reduction of the exophthalmos, with suitable ocular opening and closing under active and passive. She had no signs of keratopathy due to exposure. The upper lid covered the upper corneal limbus by 1 mm. There were neither ocular motility restrictions nor diplopia. The symptoms of photophobia, watery eyes and foreign body sensation lessened and have nearly completely disappeared. The disease has not worsened nor have there been more outbreaks (Figs. 6 and 7). Three months later there was a certain hypoesthesia around the infraorbital nerve, which diminished over time. There were no serious complications such as intraorbital hematomas or blindness.

Discussion

Surgery is the definitive treatment for thyroid-associated orbitopathy. The surgical sequence for exophthalmos is first, orbital decompression; strabismus surgery; and lastly blapharoplasty. The indications for orbital decompression are compressive neuropathy of the optic nerve, severe orbital inflammation, the presence of severe exophthalmos and the aesthetic improvement of patients.¹⁴

Different techniques have been used over the years to correct exophthalmos. In 1911 Dollinger performed an elimination of the lateral wall. In 1931 Haffziger described the approach through the orbital roof, which achieved better decompression of the orbit but required a craniotomy with the risk of meningitis and/or CRL fistula. Sewall popularized decompression following partial removal of the medial wall by means of an ethmoidectomy. In 1957 Walsh and Ogura described the Caldwell-Luc transantral approach in order to decompress the medial wall and orbital floor.⁹ Many other techniques have been described for orbital decompression, such as osteotomies of the malar with depression of the floor and medial wall¹⁰, three-wall decompression¹¹ four-wall decompression¹², lipectomy;¹³ the decompression in the lateral region of the floor and lateral wall combined with a lipectomy and osteotomy for advancing the supra-, lateral- and infraorbital rim.¹⁴ The latest advances in orbital decompression surgery use minimally invasive surgery such as endoscopic surgery or transcaruncular techniques. The caruncular approach is used for medium decompression (floor and internal wall), representing a good alternative for cases where only decompression is to be carried out with no additional surgery, either palpebral or muscular.

The technique most used is decompression that combines the partial removal of the medial wall and orbital wall, the risk of rhinorrhea, obstruction of the nasolacrimal duct and hypoesthesia of the infraorbital nerve.^15,16

For cases of severe exophthalmos (Hertel values greater than 25 mm), and for cases where orbital decompression has not had satisfactory results, a technique that can be very beneficial is three-wall decompression by means of an osteotomy to advance the supra-, lateral- and infraorbital rim in association with partial remodeling of the lateral wall and orbital floor. The technique described allows proper access to the orbital walls, facilitating the adequate reduction of the exophthalmos so as not to leave any obvious scarring. Following the incision into the periorbita, the prolapse of the periorbital fat allows the lipectomy in a simple fashion with no risk of intraorbital bleeding. If bleeding should appear, it can be controlled as it occurs outside the periorbita.

Conclusions

In cases of thyroid-associated orbitopathy with severe exophthalmos, the technique for decompression through the partial elimination of the lateral wall and orbital floor with lipectomy in association with an orbitotomy and an advancement of the supra-, lateral- and infraorbital rim, represents treatment with minimal morbidity and optimal medium and long-term results, and it is advisable for this patient type.

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