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Thyroidectomy for goiter relieves obstructive sleep apnea: results of 8 cases.

Introduction

Obstructive sleep apnea (OSA) syndrome is a common disabling condition that has been reported to affect at least 5% of the adult population. (1) Apnea is thought to occur during sleep because of periodic obstruction of the upper airway, particularly in the retropalatal and retroglossal areas of the pharynx. (2) While systemic obesity is a risk factor for OSA, neck circumference is even more closely correlated with it. (3,4) Tracheostomy has been shown to consistently eliminate OSA by providing a bypass of all upper airway obstruction in the neck, pharynx, and higher structures. (5) However, despite being the gold standard for the surgical treatment of OSA, tracheostomy is poorly tolerated and generally not well accepted by patients. (6)

Goiter is a common condition known to cause obstruction of breathing and subsequent OSA by direct compression of the trachea. (7) Direct compression of the trachea and esophagus by goiters has long been known to also cause orthopnea, obstructive dysphagia, and dyspnea. (7) Total thyroidectomy for goiter has been demonstrated to be an effective means of reducing compressive symptoms. (7) Stafford et al (8) and Deegan et al (9) reported 3 cases of goiter-induced tracheal compression in which thyroidectomy resulted in a substantial alleviation of OSA. The presence of obstructive sleep apnea and goiter has been demonstrated in other series. (10,11)

In this article, the author describes his retrospective study of the relationship between goiter-induced tracheal compression and OSA, as well as the ameliorating effects of thyroidectomy in relieving OSA.

Patients and methods

Between Jan. 1, 2004, and Dec. 31, 2007, the author treated 8 patients--1 man and 7 women, aged 21 to 83 years (mean: 54)--who had presented in a community setting with a euthyroid goiter that had caused tracheal compression and moderate to severe OSA. Detailed informed consent for inclusion in this retrospective review was obtained from all patients, and the study design was approved by the Institutional Review Board of the River Region Health System.

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Preoperative assessment. Evaluation of the goiter and tracheal compression in each patient included a comprehensive history, a complete head and neck examination, and measurement of serum thyroid-stimulating hormone (TSH); the TSH level was normal in all patients. Computed tomography (CT) of the neck and chest with intravenous contrast was used to ascertain the size of the thyroid and to confirm the presence of tracheal compression; either minimal, mild, or moderate tracheal narrowing and distortion was noted in all patients (figure).

All patients reported at least 2-pillow orthopnea and some degree of dysphagia to solids. Three patients reported nocturnal dyspnea independent of position. In addition, all patients had been screened for OSA by an assessment of daytime somnolence and fatigue, and by partner-reported snoring. Two of the 8 patients had been previously diagnosed with OSA; the remaining 6 patients had their OSA confirmed by nocturnal polysomnography. Apnea was defined as [less than or equal to] 20% airflow from baseline for [greater than or equal to] 10 seconds, and hypopnea was defined as [less than or equal to] 70% airflow from baseline for [greater than or equal to] 10 seconds with [greater than or equal to] 4% drop in Sa[O.sub.2]. All patients had an AHI of >10.

Surgery. A total thyroidectomy was performed in 5 patients, a unilateral thyroidectomy with isthmusectomy was performed in 2 patients who had asymmetric unilateral enlargement, and a completion unilateral thyroidectomy was performed in 1 patient who had been previously operated on. All procedures were performed through a standard transverse cervical incision. Bilateral laryngeal electromyography (NIM EMG Endotracheal Tube; Medtronic; Jacksonville, Fla.) was performed intraoperatively. In cases of possible parathyroid gland compromise, frozen-section biopsy and ipsilateral auto-transplantation to the sternocleidomastoid muscle were performed.

Pathologic examination of the excised tissue revealed a multinodular goiter in 7 patients and diffuse Hashimoto thyroiditis in the other.

All patients had been instructed to have their continuous positive airway pressure (CPAP) device available during the perioperative period.

Postoperative assessment. During the immediate postoperative period, patients were evaluated for airway compromise, hematoma, and vocal fold paresis. Patients reported changes in their compressive symptoms during the immediate postoperative period and again after 4 to 8 weeks. Repeat polysomnography was performed 90 days postoperatively.

To determine the effectiveness of thyroidectomy, the pre- and postoperative AHIs were compared. Statistical analysis was performed with the paired Student t test on Excel software (Microsoft; Redmond, Wash.).

Results

After thyroidectomy, all 8 patients reported alleviation of their compressive symptoms, with resolution of orthopnea, dysphagia, and dyspnea. Compared with their preoperative status, 7 of the 8 patients demonstrated postoperative reduction of their AHI. In fact, 2 patients achieved ostensible cure of their OSA; 1 experienced a reduction in AHI from 39 to 8, and the other a reduction from 16 to 1. Overall, the mean postoperative AHI decreased significantly (p < 0.05), from 52.1 to 36.6. In terms of percentage improvement, there was a 29.8% reduction in the mean AHI.

Patients were monitored for complications, and there was no perioperative airway compromise, hypocalcemia, hematoma, or weight change. One patient did develop right vocal fold paresis 2 weeks after surgery, but it resolved after 14 weeks. Patients were placed on long-term thyroid hormone replacement therapy as serologically indicated.

Discussion

These findings need to be considered in the context of the limitations of this study. First, with a sample size of only 8 patients, it would be difficult to generalize the results to larger populations. The study is underpowered; a sample size of 82 would be required to achieve statistical power. Second, it is possible that some of the changes in AHI might actually have been attributable to variability in the polysomnographic findings rather than the results of surgery; night-to-night changes in AHI can be seen in a single patient, depending on the quality of sleep and the sleeping position, as well as the specific observer's methods of technical scoring. (12) Moreover, reductions in AHI can be related to changes in body mass or levels of circulating thyroid hormone. (13)

Schwab and Goldberg described a model for the pathogenesis of OSA in adults as the closure of the retropalatal and/or retrolingual pharyngeal airway. (2) While various reconstructive procedures of the palate and tongue sometimes provide a cure, Schechtman et al (14) showed that they are not as effective as tracheostomy for the control of OSA in adults. However, because patients generally reject tracheostomy, the first-line treatment of OSA in adults is generally nonsurgical. (5)

CPAP overcomes negative airway pressure and is generally considered to be the first-line therapy for OSA. (15) But again, despite its effectiveness, CPAP is not always popular with patients, and it provides no lasting reversal of airway obstruction once the mask is removed. (16)

Another effective first-line therapy--one that can provide a permanent reversal of OSA--is weight loss. (17) In particular, OSA can be cured in morbidly obese patients who undergo massive weight loss, such as that achieved with gastric bypass surgery? (17) The mechanism by which systemic weight reduction leads to resolution of OSA remains unclear. Neck circumference is even more strongly correlated with OSA than is systemic obesity. (3,4) Koenig and Thach studied the effects of mass loading to the anterior neck on airway resistance in an animal model. (18) Although they used endoscopy to assess pharyngeal closure, it is notable that the inspiratory resistance was measured from the trachea to the nasal aperture. It is possible that the mass loading on the anterior neck contributed to increased airway resistance by direct deformation of the trachea. These earlier studies support the findings of the present study that thyromegaly and mild to moderate tracheal compression may contribute to the pathogenesis of OSA.

Thyroidectomy's effects on OSA in patients with goiter have been previously documented in several cases studies. (8-11) The results of the present study demonstrate that removal of a thyroid goiter and relief of tracheal compression can similarly reduce the severity of OSA--and even provide its cure in come cases. Further study is necessary to define the relationship between goiter, tracheal compression, and OSA, and it might lead to improved diagnosis and treatment for OSA.

References

(1.) Young T, Peppard PE, Gottlieb DJ. Epidemiology of obstructive sleep apnea: A population health perspective. Am J Respir Crit Care Med 2002; 165 (9): 1217-39.

(2.) Schwab RJ, Goldberg AN. Upper airway assessment: Radiographic and other imaging techniques. Otolaryngol Clin North Am 1998;31(6):931-68.

(3.) Katz I, Stradling J, Slutsky AS, et al. Do patients with obstructive sleep apnea have thick necks? Am Rev Respir Dis 1990; 141(5 Pt 1): 1228-31.

(4.) Davies RJ, Ali NJ, Stradling JR. Neck circumference and other clinical features in the diagnosis of the obstructive sleep apnoea syndrome. Thorax 1992;47(2):101-5.

(5.) Guilleminault C, Simmons FB, Motta J, et al. Obstructive sleep apnea syndrome and tracheostomy. Long-term follow-up experience. Arch Intern Med 1981;141(8):985-8.

(6.) Powell NB, Riley RW, Guilleminault C, Murcia GN. Obstructive sleep apnea, continuous positive airway pressure, and surgery. Otolaryngol Head Neck Surg 1988;99(4):362-9.

(7.) Netterville JL, Coleman SC, Smith JC, et al. Management of substernal goiter. Laryngoscope 1998;108(11 Pt 1):1611-17.

(8.) Stafford N, Youngs R, Waldron J, et al. Obstructive sleep apnoea in association with retrosternal goitre and acromegaly. J Laryngol Otol 1986;100(7):861-3.

(9.) Deegan PC, McNamara VM, Morgan WE. Goitre: A cause of obstructive sleep apnoea in euthyroid patients. Eur Respir J 1997;10 (2):500-2.

(10.) Eloy JA, Omerhodzic S, Som PM, Genden EM. Goitrous Hashimoto's thyroiditis presenting as obstructive sleep apnea. Thyroid 2007; 17(7):691-2.

(11.) De Felice A, Fuschillo S, Martucci M, et al. Euthyroid goitre and sleep apnea. Monaldi Arch Chest Dis 2006;65(1):52-5.

(12.) Wittig RM, Romaker A, Zorick FJ, et al. Night-to-night consistency ofapneas during sleep. Am Rev Respir Dis 1984;129(2):244-6.

(13.) Kapur VK, Koepsell TD, deMaine J, et al. Association of hypothyroidism and obstructive sleep apnea. Am J Respir Crit Care Med 1998;158(5 Pt 1):1379-83.

(14.) Schechtman KB, Sher AE, Piccirillo JF. Methodological and statistical problems in sleep apnea research: The literature on uvulopalatopharyngoplasty. Sleep 1995;18(8):659-66.

(15.) Grunstein RR. Sleep-related breathing disorders. 5. Nasal continuous positive airway pressure treatment for obstructive sleep apnoea. Thorax 1995;50(10):1106-13.

(16.) Kribbs NB, Pack AI, Kline LR, et al. Objective measurement of patterns of nasal CPAP use by patients with obstructive sleep apnea. Am Rev Respir Dis 1993;147(4):887-95.

(17.) Wittels EH, Thompson S. Obstructive sleep apnea and obesity. Otolaryngol Clin North Am 1990;23(4):751-60.

(18.) Koenig JS, Thach BT. Effects of mass loading on the upper airway. J Appl Physiol 1988;64(6):2294-9.

Mark T. Agrama, MD

Dr. Agrama is in private practice in West Palm Beach, Fla. This study was conducted when he was with the Department of Otolaryngology, River Region Health System, Vicksburg, Miss.

Correspondence: Mark T. Agrama, MD, 1411 N. Flagler Dr., Suite 4900, West Palm Beach, FL 33401. Email: mdagrama@yahoo.com

Previous presentation: The information in this article has been updated from its original presentation as a poster at the annual meeting of the American Academy of Otolaryngology-Head and Neck Surgery; Sept. 21-24, 2008; Chicago.
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Title Annotation:ORIGINAL ARTICLE
Author:Agrama, Mark T.
Publication:Ear, Nose and Throat Journal
Article Type:Report
Geographic Code:1USA
Date:Jul 1, 2011
Words:1880
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