REV I EW Open Access Hypoglossal nerve stimulation for treatment of obstructive sleep apnea (OSA): a primer for oral and maxillofacial surgeons Sung ok Hong 1 , Yu-Feng Chen 2,3 , Junho Jung 4 , Yong-Dae Kwon 2,5* and Stanley Yung Chuan Liu 6* Abstract The prevalence of obstructive sleep apnea (OSA) is estimated to be 1 – 5% of the adult population world-wide, and in Korea, it is reported at 4.5% of men and 3.2% of women (Age 40 to 69 years old). Active treatment of OSA is associated with decrease in insulin resistance, cardiovascular disease, psychosocial problems, and mortality. Surgical treatment of OSA has evolved in the era of neuromodulation with the advent of hypoglossal nerve stimulation (HGNS). We share this review of HGNS with our maxillofacial surgical colleagues to expand the scope of surgical care for OSA. Keywords: Hypoglossal nerve, Upper airway stimulation, Obstructive sleep apnea, Snoring, Sleep endoscopy, OSA surgical treatment, Oral and maxillofacial surgeon Introduction OSA prevalence The prevalence of obstructive sleep apnea (OSA) is esti- mated to be 2 – 5% of the adult population [1]. In Korea, OSA is reported in 4.5% of men and 3.2% of women between the ages of 40 to 69 years [2]. Despite a lower prevalence of obesity as compared to Western countries, the prevalence is similar in Korea. Active treatment of OSA decreases the incidence of insulin resistance, cardiovascular disease, psychosocial problems, and mortality [3 – 6]. OSA treatment Non-surgical treatments for OSA include weight loss, behavioral modifications, mandibular advancement device (MAD), and continuous positive airway pressure (CPAP). CPAP is considered as first-line treatment for OSA with well documented efficacy and morbidity. As a treatment modality, its adherence rate ranges from 39 to 50% [7 – 9]. Surgical options include soft tissue and skeletal reconstruction of the upper airway. Soft tissue procedures include septoplasty, various forms of uvulo- palatopharyngoplasty, tongue base reduction, and hyoid suspension. Common skeletal procedures include genio- glossus advancement, maxillary expansion, and maxillo- mandibular advancement (MMA). Except for tracheostomy and MMA, anatomically modifying surgeries of the upper airway report success rates ranging from 20% to 60% [10]. Besides tracheostomy, MMA is the most effective surgical treatment with success rates as high as 85.5% [11] Neurosti- mulation for stability of the upper airway during sleep was introduced as an option that may be less invasive and more effective in the well-selected patient [12]. Review Upper airway stimulation (hypoglossal nerve stimulation) History and evolution of the HGNS concept Animal studies have confirmed that the genioglossus muscle is a key protrusion muscle, as opposed to the sty- loglossus and hyoglossus muscles which retract the tongue [13]. In 1989, Miki et al. found a relationship between the hypoglossal nerve and upper airway resistance during stimulation in six canines [14]. In 1992, Schwarz et al. re- ported a correlation of V1max stimulation and decrease in critical closing pressure (Pcrit) in 18 decerebrate felines. Yoo et al. suggested that multi-contact nerve electrodes can be effective in achieving upper airway dilation and pa- tency by selective activation of various branches of the hypoglossal nerve in eight beagles [15]. Oliven et al. re- ported on the effect of airway modulation by selectively * Correspondence:
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[email protected] 2 Stanford University School of Medicine, Stanford, CA, USA 6 Department of Otolaryngology, Stanford University School of Medicine, Stanford, CA, USA Full list of author information is available at the end of the article Maxillofacial Plastic and Reconstructive Surgery © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Hong et al. Maxillofacial Plastic and Reconstructive Surgery (2017) 39:27 DOI 10.1186/s40902-017-0126-0 | The Surgical Technologist | NOVEMBER 2018 496