Selective stimulation of the hypoglossal nerve: a fine approach to treating obstructive sleep apnea

Rationale: Hypoglossal nerve stimulation (HNS) is an alternative treatment option for obstructive sleep apnea (OSA) that reduces pharyngeal collapsibility, but HNS non-responders often demonstrate continued retropalatal and lateral pharyngeal wall collapse. Recent evidence suggests that caudal pharyngeal traction with sternothyroid muscle contraction via ansa cervicalis stimulation (ACS) can also stabilize the pharynx, but the underlying mechanisms have not been elucidated. Objectives: To evaluate the effect of ACS on pharyngeal patency during expiration when the airway is most hypotonic. Methods: Eight participants with OSA underwent sustained ultrasound-guided fine-wire stimulation of the medial branch of the right hypoglossal nerve with and without transient stimulation of the branch of the ansa cervicalis nerve plexus innervating the right sternothyroid muscle during drug-induced sleep endoscopy. Airway cross-sectional area and expiratory airflow (VE) were measured from endoscopy video with ImageJ and pneumotachometry, respectively. Measurements and Main Results: ACS significantly increased retropalatal cross-sectional area (CSArp) to 211% [159-263] of unstimulated CSArp (p<0.05). Adding ACS to HNS increased CSArp from baseline by 341% [244-439] (p<0.05), a 180% [133-227] increase over isolated HNS (p<0.05). ACS increased VE from baseline by 177% [138-217] (p < 0.05). Adding ACS to HNS increased VE by 254% [207-301], reflecting decreases in pharyngeal collapsibility. Conclusions: Combining ACS with HNS increased retropalatal cross-sectional area and increased expiratory airflow, suggesting decreases in pharyngeal collapsibility. Our findings suggest that ACS exerts caudal traction on the upper airway through sternothyroid muscle contraction, and that it may augment HNS efficacy in patients with OSA.

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Therapeutic Electrical Stimulation of the Hypoglossal Nerve in Obstructive Sleep Apnea

Survey of Anesthesiology ◽

10.1097/00132586-200208000-00054 ◽

2002 ◽

Vol 46 (4) ◽

pp. 238-239

Author(s):

Kathryn E. McGoldrick

Keyword(s):

Obstructive Sleep Apnea ◽

Electrical Stimulation ◽

Sleep Apnea ◽

Hypoglossal Nerve ◽

Obstructive Sleep ◽

Stimulation Of

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Electrical stimulation of the hypoglossal nerve: a potential therapy

Journal of Applied Physiology ◽

10.1152/japplphysiol.00423.2013 ◽

2014 ◽

Vol 116 (3) ◽

pp. 337-344 ◽

Cited By ~ 27

Author(s):

Alan R. Schwartz ◽

Philip L. Smith ◽

Arie Oliven

Keyword(s):

Obstructive Sleep Apnea ◽

Electrical Stimulation ◽

Sleep Apnea ◽

Hypoglossal Nerve ◽

Therapeutic Potential ◽

Muscle Tone ◽

Feasibility Trial ◽

Airway Patency ◽

Obstructive Sleep ◽

Stimulation Of

Obstructive sleep apnea is characterized by recurrent episodes of pharyngeal collapse, which result from a decrease in pharyngeal dilator muscle tone. The genioglossus is a major pharyngeal dilator that maintains airway patency during sleep. Early studies in animal and humans have demonstrated that electrical stimulation of this muscle reduces pharyngeal collapsibility, increases airflow, and mitigates obstructive sleep apnea. These findings impelled the development of fully implantable hypoglossal nerve stimulating systems (HGNS), for which feasibility trial results are now available. These pilot studies have confirmed that hypoglossal nerve stimulation can prevent pharyngeal collapse without arousing patients from sleep. Potentially, a substantial segment of the patient population with obstructive sleep apnea can be treated with this novel approach. Furthermore, the feasibility trial findings suggest that the therapeutic potential of HGNS can be optimized by selecting patients judiciously, titrating the stimulus intensity optimally, and characterizing the underlying function and anatomy of the pharynx. These strategies are currently being examined in ongoing pivotal trials of HGNS.

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