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Implementing a hypoglossal nerve stimulation program in your sleep practice
It is estimated that almost one billion people globally are affected by obstructive sleep apnea (OSA) (Benjafield A, et al. Lancet Respir Med. 2019;7[8]:687-98). Despite such high prevalence, the treatment options for OSA are somewhat limited. As per certain estimates, nearly 50% of CPAP users discontinue treatment by the fifth year (Schoch O, et al. Respiration. 2014;87[2]:121-8). Furthermore, alternative options such as mandibular advancement devices, positional therapy, weight loss, and maxillofacial or palate surgery, also have unique challenges and limitations.
First described in 2001, hypoglossal nerve stimulation (HGNS) is a relatively new and emerging technology for the treatment of OSA (Schwartz A, et al. Arch Otolaryngol Head Neck Surg. 2001 Oct;127[10]:1216-23). HGNS therapy was approved by the Food and Drug Administration in 2014 for the treatment of moderate to severe OSA. The therapy involves surgical implantation of the HGNS device, optimization of device settings, and evaluation for treatment response. A physician-led multidisciplinary Hypoglossal Nerve Stimulation Clinic involves collaboration from essential stakeholders, most importantly sleep medicine providers, clinic staff, sleep technologists, and ENT sleep surgeons. Goals of the multidisciplinary program are to ensure timely follow-up, optimization of device settings, and maximizing treatment efficacy. This review describes steps involved in developing a successful multidisciplinary HGNS program within a sleep medicine practice.
Patient selection and evaluation
There is growing interest in HGNS relative to conventional CPAP therapy, with many patients presenting to clinic to inquire about this therapy. However, not all patients are candidates for HGNS therapy. Prioritizing appropriate patient selection and education are key first steps. The initial assessments usually occur with a sleep medicine specialist. It begins with confirmation of the diagnosis of OSA in all patients and a concerted effort to troubleshoot and address any barriers to CPAP use before consideration of surgery. Patients who are unwilling to use or unable to tolerate CPAP therapy undergo further evaluation for HGNS therapy. It is important to ensure that patients are also screened for other sleep disorders, such as insomnia or restless leg syndrome, to rule out its contribution to daytime (or nighttime) symptoms.
Other salient inclusion criteria include an apnea-hypopnea index (AHI) between 15-100 events per hour (previously 65), at least 18 years of age, and a body mass index (BMI) less than 40 kg/m2 (previously 32). Qualifying patients undergo an updated polysomnography if a recent study is not available. If the polysomnography reveals central and mixed apneas comprising less than 25 percent of the total AHI, patients are referred to ENT Sleep Surgery, and drug-induced sleep endoscopy is offered to examine upper airway anatomy. When a complete concentric collapse of the soft palate is seen on drug-induced sleep endoscopy, surgery is contraindicated. Prior palate surgery or maxillomandibular advancement (MMA) are not contraindications to HGNS therapy.
The patients receive comprehensive information on the nature of the surgery, expected recovery course, and device activation timeline. Perhaps most importantly, the patients receive structured education on HGNS therapy and potential outcomes to set realistic expectations. In the STAR trial, patients experienced a reduction in the AHI of approximately 70% (Strollo P, et al. N Engl J Med. 2014;370[2]:139-49). It is important to note that a response to therapy was defined as a reduction in the AHI by at least 50% and a value less than 20 events/hour (Strollo P, et al. Sleep. 2015;38[10]:1593-8). Therefore, patients who are expecting complete resolution of snoring and/or OSA may not be ideal candidates for surgery. Furthermore, patients who continue to experience fatigue and sleepiness on CPAP despite control of OSA may not experience amelioration of these symptoms with HGNS therapy.
Surgery and device management
The surgery, performed under general anesthesia, lasts approximately 3 hours, and may be followed by an overnight hospital stay depending on patient’s comorbidities. The device implantation involves placement of an implantable pulse generator (IPG) in the chest wall and leads to the hypoglossal nerve. The IPG is similar to a pacemaker and functions to stimulate the ipsilateral hypoglossal nerve innervating the tongue during sleep. The most common postoperative complications noted in the STAR trial data include incision site pain and swelling as well as temporary tongue weakness or paresthesia. Postoperative restrictions are minimal and include no heavy lifting for one month after surgery.
One week postsurgery, patients return to the ENT Sleep Surgery Clinic for follow-up, at which time the incisions as well as tongue strength and sensation are evaluated. In a subsequent visit between 4 and 6 weeks postsurgery, patients are evaluated in a joint Sleep Medicine and ENT clinic. They undergo device education and activation of the IPG using a dedicated programmer obtained from the device manufacturer. Device comfort features such as start delay and pause time are also programmed. Furthermore, appropriate tongue movement, lead placement, and voltage range settings are assessed during the visit. The ENT surgery team reevaluates the incision sites and assesses for tongue function and sensation. Patients are instructed to increase the voltage incrementally every week as tolerated with the goal of using the device nightly for the entirety of sleep. If patients tolerate the therapy well during the 2- to 3-month follow-up, a sleep study is scheduled to evaluate treatment effectiveness at the peak tolerable voltage. For those struggling with the therapy, adjustments to electrode configurations should be considered for pulse width, and rate. Occasionally, patients may require awake endoscopy and/or an advanced HGNS titration while asleep to determine the most appropriate settings to optimally control sleep apnea.
Until recently, patients implanted with an early version of the HGNS were limited to magnetic resonance imaging (MRI) scans of the head, neck, and extremities only. However, patients with the latest model IPGs can now undergo full-body MRI scans. It is important to note that the MRI’s Tesla cannot exceed 1.5T, necessitating specific imaging centers. Other constraints include the inability to adjust device settings remotely, which could mean long travel for minor setting adjustments such as altering start delay or pause times. Furthermore, provider education on operating and managing the device can be time consuming and may also be a barrier to implementation in a clinic. Also challenging may be the availability of an ENT surgery, which plays a critical role in the implantation of the devices and follow-up.
Currently, Inspire Medical Systems is the only FDA-approved hypoglossal nerve stimulation device available in the United States, and globally, more than 45,000 patients have been implanted. However, the field of neurostimulation is rapidly growing. Companies like LivaNova have secured Investigational Device Exemption for their HGNS device. The Genio system by Nyxoah is evaluating the use of bilateral hypoglossal nerve stimulation in patients with OSA and complete concentric collapse of the palate. A multidisciplinary Hypoglossal Nerve Stimulation Clinic is an important component of a comprehensive sleep medicine clinic for patient care and medical education. In the appropriate patient, this emerging technology may provide improvement in OSA severity and symptoms.
Dr. Gill is Clinical Associate Professor, Division of Sleep Medicine, Stanford (Calif.) University.
It is estimated that almost one billion people globally are affected by obstructive sleep apnea (OSA) (Benjafield A, et al. Lancet Respir Med. 2019;7[8]:687-98). Despite such high prevalence, the treatment options for OSA are somewhat limited. As per certain estimates, nearly 50% of CPAP users discontinue treatment by the fifth year (Schoch O, et al. Respiration. 2014;87[2]:121-8). Furthermore, alternative options such as mandibular advancement devices, positional therapy, weight loss, and maxillofacial or palate surgery, also have unique challenges and limitations.
First described in 2001, hypoglossal nerve stimulation (HGNS) is a relatively new and emerging technology for the treatment of OSA (Schwartz A, et al. Arch Otolaryngol Head Neck Surg. 2001 Oct;127[10]:1216-23). HGNS therapy was approved by the Food and Drug Administration in 2014 for the treatment of moderate to severe OSA. The therapy involves surgical implantation of the HGNS device, optimization of device settings, and evaluation for treatment response. A physician-led multidisciplinary Hypoglossal Nerve Stimulation Clinic involves collaboration from essential stakeholders, most importantly sleep medicine providers, clinic staff, sleep technologists, and ENT sleep surgeons. Goals of the multidisciplinary program are to ensure timely follow-up, optimization of device settings, and maximizing treatment efficacy. This review describes steps involved in developing a successful multidisciplinary HGNS program within a sleep medicine practice.
Patient selection and evaluation
There is growing interest in HGNS relative to conventional CPAP therapy, with many patients presenting to clinic to inquire about this therapy. However, not all patients are candidates for HGNS therapy. Prioritizing appropriate patient selection and education are key first steps. The initial assessments usually occur with a sleep medicine specialist. It begins with confirmation of the diagnosis of OSA in all patients and a concerted effort to troubleshoot and address any barriers to CPAP use before consideration of surgery. Patients who are unwilling to use or unable to tolerate CPAP therapy undergo further evaluation for HGNS therapy. It is important to ensure that patients are also screened for other sleep disorders, such as insomnia or restless leg syndrome, to rule out its contribution to daytime (or nighttime) symptoms.
Other salient inclusion criteria include an apnea-hypopnea index (AHI) between 15-100 events per hour (previously 65), at least 18 years of age, and a body mass index (BMI) less than 40 kg/m2 (previously 32). Qualifying patients undergo an updated polysomnography if a recent study is not available. If the polysomnography reveals central and mixed apneas comprising less than 25 percent of the total AHI, patients are referred to ENT Sleep Surgery, and drug-induced sleep endoscopy is offered to examine upper airway anatomy. When a complete concentric collapse of the soft palate is seen on drug-induced sleep endoscopy, surgery is contraindicated. Prior palate surgery or maxillomandibular advancement (MMA) are not contraindications to HGNS therapy.
The patients receive comprehensive information on the nature of the surgery, expected recovery course, and device activation timeline. Perhaps most importantly, the patients receive structured education on HGNS therapy and potential outcomes to set realistic expectations. In the STAR trial, patients experienced a reduction in the AHI of approximately 70% (Strollo P, et al. N Engl J Med. 2014;370[2]:139-49). It is important to note that a response to therapy was defined as a reduction in the AHI by at least 50% and a value less than 20 events/hour (Strollo P, et al. Sleep. 2015;38[10]:1593-8). Therefore, patients who are expecting complete resolution of snoring and/or OSA may not be ideal candidates for surgery. Furthermore, patients who continue to experience fatigue and sleepiness on CPAP despite control of OSA may not experience amelioration of these symptoms with HGNS therapy.
Surgery and device management
The surgery, performed under general anesthesia, lasts approximately 3 hours, and may be followed by an overnight hospital stay depending on patient’s comorbidities. The device implantation involves placement of an implantable pulse generator (IPG) in the chest wall and leads to the hypoglossal nerve. The IPG is similar to a pacemaker and functions to stimulate the ipsilateral hypoglossal nerve innervating the tongue during sleep. The most common postoperative complications noted in the STAR trial data include incision site pain and swelling as well as temporary tongue weakness or paresthesia. Postoperative restrictions are minimal and include no heavy lifting for one month after surgery.
One week postsurgery, patients return to the ENT Sleep Surgery Clinic for follow-up, at which time the incisions as well as tongue strength and sensation are evaluated. In a subsequent visit between 4 and 6 weeks postsurgery, patients are evaluated in a joint Sleep Medicine and ENT clinic. They undergo device education and activation of the IPG using a dedicated programmer obtained from the device manufacturer. Device comfort features such as start delay and pause time are also programmed. Furthermore, appropriate tongue movement, lead placement, and voltage range settings are assessed during the visit. The ENT surgery team reevaluates the incision sites and assesses for tongue function and sensation. Patients are instructed to increase the voltage incrementally every week as tolerated with the goal of using the device nightly for the entirety of sleep. If patients tolerate the therapy well during the 2- to 3-month follow-up, a sleep study is scheduled to evaluate treatment effectiveness at the peak tolerable voltage. For those struggling with the therapy, adjustments to electrode configurations should be considered for pulse width, and rate. Occasionally, patients may require awake endoscopy and/or an advanced HGNS titration while asleep to determine the most appropriate settings to optimally control sleep apnea.
Until recently, patients implanted with an early version of the HGNS were limited to magnetic resonance imaging (MRI) scans of the head, neck, and extremities only. However, patients with the latest model IPGs can now undergo full-body MRI scans. It is important to note that the MRI’s Tesla cannot exceed 1.5T, necessitating specific imaging centers. Other constraints include the inability to adjust device settings remotely, which could mean long travel for minor setting adjustments such as altering start delay or pause times. Furthermore, provider education on operating and managing the device can be time consuming and may also be a barrier to implementation in a clinic. Also challenging may be the availability of an ENT surgery, which plays a critical role in the implantation of the devices and follow-up.
Currently, Inspire Medical Systems is the only FDA-approved hypoglossal nerve stimulation device available in the United States, and globally, more than 45,000 patients have been implanted. However, the field of neurostimulation is rapidly growing. Companies like LivaNova have secured Investigational Device Exemption for their HGNS device. The Genio system by Nyxoah is evaluating the use of bilateral hypoglossal nerve stimulation in patients with OSA and complete concentric collapse of the palate. A multidisciplinary Hypoglossal Nerve Stimulation Clinic is an important component of a comprehensive sleep medicine clinic for patient care and medical education. In the appropriate patient, this emerging technology may provide improvement in OSA severity and symptoms.
Dr. Gill is Clinical Associate Professor, Division of Sleep Medicine, Stanford (Calif.) University.
It is estimated that almost one billion people globally are affected by obstructive sleep apnea (OSA) (Benjafield A, et al. Lancet Respir Med. 2019;7[8]:687-98). Despite such high prevalence, the treatment options for OSA are somewhat limited. As per certain estimates, nearly 50% of CPAP users discontinue treatment by the fifth year (Schoch O, et al. Respiration. 2014;87[2]:121-8). Furthermore, alternative options such as mandibular advancement devices, positional therapy, weight loss, and maxillofacial or palate surgery, also have unique challenges and limitations.
First described in 2001, hypoglossal nerve stimulation (HGNS) is a relatively new and emerging technology for the treatment of OSA (Schwartz A, et al. Arch Otolaryngol Head Neck Surg. 2001 Oct;127[10]:1216-23). HGNS therapy was approved by the Food and Drug Administration in 2014 for the treatment of moderate to severe OSA. The therapy involves surgical implantation of the HGNS device, optimization of device settings, and evaluation for treatment response. A physician-led multidisciplinary Hypoglossal Nerve Stimulation Clinic involves collaboration from essential stakeholders, most importantly sleep medicine providers, clinic staff, sleep technologists, and ENT sleep surgeons. Goals of the multidisciplinary program are to ensure timely follow-up, optimization of device settings, and maximizing treatment efficacy. This review describes steps involved in developing a successful multidisciplinary HGNS program within a sleep medicine practice.
Patient selection and evaluation
There is growing interest in HGNS relative to conventional CPAP therapy, with many patients presenting to clinic to inquire about this therapy. However, not all patients are candidates for HGNS therapy. Prioritizing appropriate patient selection and education are key first steps. The initial assessments usually occur with a sleep medicine specialist. It begins with confirmation of the diagnosis of OSA in all patients and a concerted effort to troubleshoot and address any barriers to CPAP use before consideration of surgery. Patients who are unwilling to use or unable to tolerate CPAP therapy undergo further evaluation for HGNS therapy. It is important to ensure that patients are also screened for other sleep disorders, such as insomnia or restless leg syndrome, to rule out its contribution to daytime (or nighttime) symptoms.
Other salient inclusion criteria include an apnea-hypopnea index (AHI) between 15-100 events per hour (previously 65), at least 18 years of age, and a body mass index (BMI) less than 40 kg/m2 (previously 32). Qualifying patients undergo an updated polysomnography if a recent study is not available. If the polysomnography reveals central and mixed apneas comprising less than 25 percent of the total AHI, patients are referred to ENT Sleep Surgery, and drug-induced sleep endoscopy is offered to examine upper airway anatomy. When a complete concentric collapse of the soft palate is seen on drug-induced sleep endoscopy, surgery is contraindicated. Prior palate surgery or maxillomandibular advancement (MMA) are not contraindications to HGNS therapy.
The patients receive comprehensive information on the nature of the surgery, expected recovery course, and device activation timeline. Perhaps most importantly, the patients receive structured education on HGNS therapy and potential outcomes to set realistic expectations. In the STAR trial, patients experienced a reduction in the AHI of approximately 70% (Strollo P, et al. N Engl J Med. 2014;370[2]:139-49). It is important to note that a response to therapy was defined as a reduction in the AHI by at least 50% and a value less than 20 events/hour (Strollo P, et al. Sleep. 2015;38[10]:1593-8). Therefore, patients who are expecting complete resolution of snoring and/or OSA may not be ideal candidates for surgery. Furthermore, patients who continue to experience fatigue and sleepiness on CPAP despite control of OSA may not experience amelioration of these symptoms with HGNS therapy.
Surgery and device management
The surgery, performed under general anesthesia, lasts approximately 3 hours, and may be followed by an overnight hospital stay depending on patient’s comorbidities. The device implantation involves placement of an implantable pulse generator (IPG) in the chest wall and leads to the hypoglossal nerve. The IPG is similar to a pacemaker and functions to stimulate the ipsilateral hypoglossal nerve innervating the tongue during sleep. The most common postoperative complications noted in the STAR trial data include incision site pain and swelling as well as temporary tongue weakness or paresthesia. Postoperative restrictions are minimal and include no heavy lifting for one month after surgery.
One week postsurgery, patients return to the ENT Sleep Surgery Clinic for follow-up, at which time the incisions as well as tongue strength and sensation are evaluated. In a subsequent visit between 4 and 6 weeks postsurgery, patients are evaluated in a joint Sleep Medicine and ENT clinic. They undergo device education and activation of the IPG using a dedicated programmer obtained from the device manufacturer. Device comfort features such as start delay and pause time are also programmed. Furthermore, appropriate tongue movement, lead placement, and voltage range settings are assessed during the visit. The ENT surgery team reevaluates the incision sites and assesses for tongue function and sensation. Patients are instructed to increase the voltage incrementally every week as tolerated with the goal of using the device nightly for the entirety of sleep. If patients tolerate the therapy well during the 2- to 3-month follow-up, a sleep study is scheduled to evaluate treatment effectiveness at the peak tolerable voltage. For those struggling with the therapy, adjustments to electrode configurations should be considered for pulse width, and rate. Occasionally, patients may require awake endoscopy and/or an advanced HGNS titration while asleep to determine the most appropriate settings to optimally control sleep apnea.
Until recently, patients implanted with an early version of the HGNS were limited to magnetic resonance imaging (MRI) scans of the head, neck, and extremities only. However, patients with the latest model IPGs can now undergo full-body MRI scans. It is important to note that the MRI’s Tesla cannot exceed 1.5T, necessitating specific imaging centers. Other constraints include the inability to adjust device settings remotely, which could mean long travel for minor setting adjustments such as altering start delay or pause times. Furthermore, provider education on operating and managing the device can be time consuming and may also be a barrier to implementation in a clinic. Also challenging may be the availability of an ENT surgery, which plays a critical role in the implantation of the devices and follow-up.
Currently, Inspire Medical Systems is the only FDA-approved hypoglossal nerve stimulation device available in the United States, and globally, more than 45,000 patients have been implanted. However, the field of neurostimulation is rapidly growing. Companies like LivaNova have secured Investigational Device Exemption for their HGNS device. The Genio system by Nyxoah is evaluating the use of bilateral hypoglossal nerve stimulation in patients with OSA and complete concentric collapse of the palate. A multidisciplinary Hypoglossal Nerve Stimulation Clinic is an important component of a comprehensive sleep medicine clinic for patient care and medical education. In the appropriate patient, this emerging technology may provide improvement in OSA severity and symptoms.
Dr. Gill is Clinical Associate Professor, Division of Sleep Medicine, Stanford (Calif.) University.