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Surgical Correction of the Acromegalic Face
J. Timothy Katzen M.D., Mohamed S. Kabil., Hrayr K. Shahinian M.D.

Introduction and overall concepts

Acromegaly was first described by Marie in 1886. It was not until 1909 that Cushing and Davidoff suspected that the pituitary was the source of this condition. This hypothesis was supported once neurosurgical access to the pituitary had been gained and it became possible to remove pituitary tumors, which resulted in reversal of acromegalic features. It is now well recognized that pituitary growth hormone is regulated, in part, by dual signals from other parts of the brain. We summarize recent advances in the understanding of the pathogenesis, diagnosis and management of acromegaly with special emphasis on surgical correction of the acromegalic face.

Patients with growth hormone secreting pituitary adenomas frequently develop abnormal craniofacial bone growth. Collectively, these physical features along with enlargement of the hands and feet are called acromegaly. It is a chronic, slowly developing disease characterized by progressive disfigurement and disability. The disfigurement of the face occurs insidiously in most patients and develops only slowly, so that very often the disorder is diagnosed only when a new physician replaces the usual doctor and sees the patient for the first time, and/or when photographs of the patient taken over a number of years are collected together. Apart from the cosmetic changes, a multitude of complaints interfere with normal daily working life of the affected patients, these include cardiovascular, respiratory, metabolic and endocrinal.1

Unfortunately, even long after the removal of a patient's pituitary tumor and when growth hormone levels return to normal, the disproportionate facial features do not return to their previous appearance.

Many patients are troubled by the way they look after their pituitary tumor is removed. Now, through surgical reconstructive techniques employed by craniofacial surgeons these abnormalities could be corrected.

Pathogenesis and diagnosis

The clinical syndrome of acromegaly is caused in virtually all patients by growth hormone (GH)-secreting pituitary adenomas, about 40% of which are microadenomas (<10 mm in diameter). Excessive production of GH also results in an increased production of tissue growth factors such as insulin-like growth factor-I (IGF-I). An early diagnosis of acromegaly is difficult and, in the majority of patients, the long delay in diagnosis results in the development of irreversible complications in several organ systems. Most signs and symptoms of acromegaly are the result of the long-standing overproduction of GH and/or IGF-I, leading to morphological, endocrine and metabolic changes. Symptoms may also be directly related to pressure caused by supra-sellar extension of the pituitary adenoma, including visual field defects, loss of visual acuity and headaches, and loss of anterior pituitary function results in lethargy, infertility, and loss of libido.2

Clinical presentation and physical changes

As a direct result of the high amount of growth hormone secreted by the pituitary gland, the skull and face grow disproportionately. The more growth hormone secreted, the more the skull and face continues to grow. These facial differences can include frontal bossing (large forehead), prominent supraorbital ridges (large eyebrow ridges), malar flatness and maxillary hypoplasia (a small upper jaw with flat cheeks), as well as mandibular prognathism (a large lower jaw) resulting in malocclusion (teeth that don't line up).3,4 The compressive effects often include peripheral visual-field impairment and headaches. The long-standing effects of growth-hormone excess include a series of characteristic clinical features.

Although the coarsening of facial features may seem to be obvious in retrospect, only 10% of patients with acromegaly consult a physician for that complaint.5 Excessive sweating, interruption of menstrual periods, impotence, diabetes mellitus, sleep apnea and skin tags are also common features of the disorder. In two thirds of patients with acromegaly, sleep apnea is obstructive, and in the other third, a central cause is identified,6 which may be a dysfunction in central somatostatinergic pathways, a putative factor in the control of breathing. It is also common for patients to present with seemingly unrelated complaints such as carpal tunnel syndrome, jaw malocclusion, arthritis or colonic polyps. Adenomatous polyps of the colon appear to be associated with skin tags and may become a significant cause of morbidity and mortality in aging patients with acromegaly.

If left untreated, acromegaly results in disabling arthritis, visual impairment, hypertension, cardiomyopathy, frank diabetes mellitus, sleep apnea and pituitary failure.7-10 Acromegaly may be associated with an increased risk of cancer of the gastrointestinal tract.13 Treatment can have a significant effect on the course of the disease and, in many cases, can result in a normal life expectancy.11 Therefore, it is crucial that appropriate studies are undertaken to establish the diagnosis, find the source of excess growth-hormone production and monitor the success of therapy, once it has been started.

Treatment modalities

The aims of treatment of acromegaly are to induce a biochemical remission of the hypersecretory state with its associated complications and to relieve the compressive effects of a growing pituitary mass.

Means of treatment of acromegaly include transsphenoidal surgery for the pituitary gland, external radiotherapy and/or radiosurgery on the pituitary gland, and medical therapy (dopamine and somatostatin analogues) to antagonize the effect of excessive hormone secretion. Because each of these modalities have important shortcomings and side-effects, combinations of one, two, or all of these forms of therapy are often offered to acromegalic patients.3 Regardless of the approach, it is important to recognize that to fulfill these criteria is to effect a cure, and that this often difficult to achieve. Partial fulfillment of the criteria is considered control of the disease which in itself is an important target.12

Corrective Surgery

Previously, surgical correction of the physical deformities of acromegaly required a large, interdisciplinary team and included multiple, long, hospital stays, weeks of the teeth being wired together, and often the placement of a tracheostomy (breathing tube in the neck). Now, correction of many of these deformities can be performed usually in a single operation. Typically, patients spend a few days the hospital, do not require wiring of their teeth, nor do they require a tracheostomy.3, 13

Each patient is an individual and his or her surgical requirements often vary dramatically. Consequently, each operation must be tailored to each patient's specific needs. Typically, the surgery entails three incisions. All the incisions are hidden from view. Two buccal incisions (hidden inside the mouth) are used, one is made just behind the upper lip and the other is made behind the lower lip. The operation begins with correction of the mandibular prognathism (a large lower jaw). The mandible (jaw bone) and soft tissue of the lower jaw are reduced. Then, attention is focused on the midface (cheek bones and upper jaw). Typically, the midface is augmented or increased in profile depending on the patient's appearance. Extra special care is taken to ensure that the teeth line up. In the past, this would have required that the teeth be wired shut and a tracheostomy be performed. Using a preoperatively fabricated splint, the teeth can now be aligned perfectly in the operating room, thus avoiding the need for wiring the teeth together. The coronal incision is the third incision, and is made across the top of the head, behind the hair line. This allows access to the frontal bones (forehead) and supraorbital ridges (eyebrows ridges). The forehead and eyebrow ridge are then contoured into a more normal shaped bone. Additional procedures may involve a reduction in the size of the tongue and other soft tissues.

Typically, there is a dramatic improvement in the patient's physical appearance, psyche, and speech.14

Conclusion

Acromegaly may be a potentially life-threatening disease if left untreated. However, the diease could be controlled by applying the proper modality of treatment, or by the combination of more than one modality according to each individual case. The physical changes that accompany the disease are obvious and usually have a negative impact on the psychological condition of the patient. Recent advances in craniofacial reconstruction have dramatically improved cosmetic outcomes for acromegalic patients. Advances have obviated the need for a tracheostomy and have resulted in single stage operations with a short hospitalization. With the advent of new reconstructive materials and instruments, craniofacial surgeons will continue to develop improved methods of correcting the facial abnormalities that result from excess growth hormone secretion.

References
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