Successful Hypoglossal Nerve Upper Airway Stimulator Implantation After Chemoradiotherapy for Oropharynx Malignancy Complicated by Mandibular Osteoradionecrosis

Abstract

This case demonstrates the first successful treatment of obstructive sleep apnea with hypoglossal nerve upper airway stimulation in a patient with prior radiation for oropharynx cancer complicated by osteoradionecrosis of the mandible.

Obstructive sleep apnea (OSA) has a high prevalence in patients with a history of radiation therapy (RT) to the head and neck (12%-40%).^1,2 The morbidity of untreated OSA is well established including increased cardiovascular and cerebrovascular disease-related morbidity and mortality. ³ Continuous positive airway pressure (CPAP) therapy is the gold standard treatment, however, compliance is poor^4,5 and patients often desire a definitive surgical solution. We present a case of a hypoglossal nerve upper airway stimulator (HNS-UAS) implantation for OSA in a patient who underwent prior chemoradiotherapy for tonsillar carcinoma with treatment course complicated by osteoradionecrosis (ORN) of the mandible. There is a paucity of data on HNS-UAS outcomes in head and neck cancer survivors, and to our knowledge, this is the second report of successful treatment in this patient demographic. ⁶

A 71-year-old male Veteran with a 20-year history of OSA on CPAP presented with complaints of worsening fatigue associated with decline in CPAP tolerance. His medical history was notable for T1N2bM0 P16+ left tonsillar squamous cell carcinoma treated with definitive RT and concurrent cisplatin 5 years earlier. His course was complicated by significant ORN of the left mandible treated with a segmental mandibulectomy and internal fixation 3 years after completion of radiotherapy.

Upon evaluation for HNS-UAS, the patient had a body mass index of 28.75, and physical examination findings demonstrating postradiation changes in the left neck, moderate trismus, and postradiation mucosal changes in the oropharynx. An in-lab polysomnography (PSG) demonstrated combined obstructive and central sleep apnea, with apnea–hypopnea index (AHI) 38 events/hour and oxygen nadir 85%. The patient underwent a drug-induced sleep endoscopy (DISE) demonstrating complete anterior–posterior collapse at the velum and epiglottis.

The patient fulfilled all criteria for hypoglossal nerve stimulator (HNS) implantation. He was informed of the increased risk of postoperative complications and unknown treatment efficacy given his history of radiotherapy to the oropharynx and complications from ORN. An Inspire UAS system (Inspire Medical Systems) was subsequently implanted in standard fashion. Intraoperative dissection was challenging due to severity of soft tissue fibrosis in the neck; however, after successful implant placement, the genioglossus muscle activation was confirmed with intraoperative electromyographic monitoring and direct visualization.

Postoperatively, the patient experienced routine recovery from upper airway stimulator (UAS) surgery. Device activation occurred one month postoperatively with device amplitude set at 1.4 Volts (V). Two months postoperatively, the patient reported throat discomfort and otalgia requiring device titration to 0.9 V. Eleven months postoperatively, the patient underwent a PSG with device amplitude at 1.3 V demonstrating successful treatment of OSA with an AHI of 4, Epworth Sleepiness Scale (2/24).

Since publication of the STAR trial ⁷ in 2014, the HNS-UAS has proven it’s long-term therapeutic efficacy, low complication rates and high patient tolerance in multiple follow-up studies.^8,9 Selection criteria are widely utilized and include moderate–severe OSA, lack of clinically significant central or mixed sleep apnea, and absence of concentric retropalatal airway collapse on DISE. The clinical trials to date have not included cohorts of head and neck cancer survivors. A recent ADHERE registry study demonstrated that older adults (>65 years old) with moderate–severe OSA performed better in AHI reduction than their younger counterparts. ¹⁰ Head and neck cancer treatment survivors often fall within this older patient demographic also having concurrent risk factors for poorer outcome including prior surgery (ie, neck dissection, oropharyngectomy), adjuvant RT, and overall poorer performance (ie, Eastern Cooperative Oncology Group status). These factors likely impact the efficacy of UAS by changing the physiology of the upper aerodigestive tract, pharyngeal muscle tone, and tongue protrusion. It could be postulated that head and neck cancer survivors, particularly those who have RT would have poorer treatment response to HNS-UAS. However, the patient in our study demonstrated excellent 1-year postoperative results (AHI 4), and a prior case report from 2017 demonstrated an excellent 1-year postoperative result as well (AHI 8). ⁶ These data are encouraging for the use of HNS-UAS in survivors of oropharynx malignancy treated with RT.

In conclusion, this case report supports the use of HNS-UAS in patients who meet standard criteria for HNS and have undergone prior RT for malignancy of the oropharynx. However, future clinical trials are required to further demonstrate treatment efficacy, low complication rate(s), and high patient tolerance of HNS-UAS in this patient population and demonstrate acceptable long-term outcomes and improvement in OSA-related morbidity and mortality.