Device-related outcomes following hypoglossal nerve stimulator implantation

STUDY OBJECTIVES

Hypoglossal nerve stimulation (HGNS) has been widely used to treat obstructive sleep apnea in selected patients. Here we evaluate rates of revision and explant related to HGNS implantation and assess types of adverse events contributing to revision and explant.

METHODS

Post-market surveillance data for HGNS implanted between January 1, 2018 and March 31, 2022, were collected. Event rates and risk were calculated using the post-market surveillance event counts and sales volume over the same period. Indications were categorized for analysis. Descriptive statistics were reported and freedom from explant or revision curves were grouped by year of implantation.

RESULTS

Of the 20,881 HGNS implants assessed, rates of explant and revision within the first year were 0.723% and 1.542%, respectively. The most common indication for explant was infection (0.378%) and for revision was surgical correction (0.680%). Of the 5,820 devices with three-year post-implantation data, the rate of explant was 2.680% and of revision was 3.557%. During this same interval, elective removal (1.478%) was the most common indication, and for revisions, surgical correction (1.134%).

CONCLUSIONS

The efficacy of HGNS is comparable in the real world setting to published clinical trial data. Rates of explant and revision are low, supporting a satisfactory safety profile for this technology.

Hypoglossal Nerve Stimulation and Cardiovascular Outcomes for Patients With Obstructive Sleep Apnea: A Randomized Clinical Trial

Importance

Sham-controlled trials are needed to characterize the effect of hypoglossal nerve stimulation (HGNS) therapy on cardiovascular end points in patients with moderate-severe obstructive sleep apnea (OSA).

Objective

To determine the effect of therapeutic levels of HGNS, compared to sham levels, on blood pressure, sympathetic activity, and vascular function.

Design, Setting, and Participants

This double-blind, sham-controlled, randomized crossover therapy trial was conducted from 2018 to 2022 at 3 separate academic medical centers. Adult patients with OSA who already had an HGNS device implanted and were adherent and clinically optimized to HGNS therapy were included. Participants who had fallen asleep while driving within 1 year prior to HGNS implantation were excluded from the trial. Data analysis was performed from January to September 2022.

Interventions

Participants underwent a 4-week period of active HGNS therapy and a 4-week period of sham HGNS therapy in a randomized order. Each 4-week period concluded with collection of 24-hour ambulatory blood pressure monitoring (ABPM), pre-ejection period (PEP), and flow-mediated dilation (FMD) values.

Main Outcomes and Measures

The change in mean 24-hour systolic blood pressure was the primary outcome, with other ABPM end points exploratory, and PEP and FMD were cosecondary end points.

Results

Participants (n = 60) were older (mean [SD] age, 67.3 [9.9] years), overweight (mean [SD] body mass index, calculated as weight in kilograms divided by height in meters squared, 28.7 [4.6]), predominantly male (38 [63%]), and had severe OSA at baseline (mean [SD] apnea-hypopnea index, 33.1 [14.9] events/h). There were no differences observed between active and sham therapy in 24-hour systolic blood pressure (mean change on active therapy, -0.18 [95% CI, -2.21 to 1.84] mm Hg), PEP (mean change on active therapy, 0.11 [95% CI, -5.43 to 5.66] milliseconds), or FMD (mean change on active therapy, -0.17% [95% CI, -1.88% to 1.54%]). Larger differences between active and sham therapy were observed in a per-protocol analysis set (n = 20) defined as experiencing at least a 50% reduction in apnea-hypopnea index between sham and active treatment.

Conclusions and Relevance

In this sham-controlled HGNS randomized clinical trial, mean 24-hour systolic blood pressure and other cardiovascular measures were not significantly different between sham and active HGNS therapy. Several methodologic lessons can be gleaned to inform future HGNS randomized clinical trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT03359096.

Evaluating ChatGPT responses on obstructive sleep apnea for patient education

STUDY OBJECTIVES

We evaluated the quality of ChatGPT responses to questions on obstructive sleep apnea for patient education and assessed how prompting the chatbot influences correctness, estimated grade level, and references of answers.

METHODS

ChatGPT was queried 4 times with 24 identical questions. Queries differed by initial prompting: no prompting, patient-friendly prompting, physician-level prompting, and prompting for statistics/references. Answers were scored on a hierarchical scale: incorrect, partially correct, correct, correct with either statistic or referenced citation ("correct+"), or correct with both a statistic and citation ("perfect"). Flesch-Kincaid grade level and citation publication years were recorded for answers. Proportions of responses at incremental score thresholds were compared by prompt type using chi-squared analysis. The relationship between prompt type and grade level was assessed using analysis of variance.

RESULTS

Across all prompts (n = 96 questions), 69 answers (71.9%) were at least correct. Proportions of responses that were at least partially correct (P = .387) or correct (P = .453) did not differ by prompt; responses that were at least correct+ (P < .001) or perfect (P < .001) did. Statistics/references prompting provided 74/77 (96.1%) references. Responses from patient-friendly prompting had a lower mean grade level (12.45 ± 2.32) than no prompting (14.15 ± 1.59), physician-level prompting (14.27 ± 2.09), and statistics/references prompting (15.00 ± 2.26) (P < .0001).

CONCLUSIONS

ChatGPT overall provides appropriate answers to most questions on obstructive sleep apnea regardless of prompting. While prompting decreases response grade level, all responses remained above accepted recommendations for presenting medical information to patients. Given ChatGPT's rapid implementation, sleep experts may seek to further scrutinize its medical literacy and utility for patients.

CITATION

Campbell DJ, Estephan LE, Mastrolonardo EV, Amin DR, Huntley CT, Boon MS. Evaluating ChatGPT responses on obstructive sleep apnea for patient education. J Clin Sleep Med. 2023;19(12):1989-1995.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

A systematic approach to the evaluation and management of obstructive sleep apnea: The Jefferson Protocol

Obstructive sleep apnea (OSA) has become increasingly prevalent in the United States. While continuous positive airway pressure (CPAP) therapy remains the gold standard for treatment, surgical intervention can enhance compliance and improve outcomes for those intolerant of CPAP. Since the majority of OSA patients have multilevel obstruction, it is critical that otolaryngologists understand each patient's pattern and anatomic level of obstruction before solidifying a treatment plan. This publication serves as a comprehensive review of evaluation, characterization, and management of OSA. Further, the authors outline their departmental algorithm for identifying ideal surgical candidates and tailoring corresponding surgical interventions.

Drug-Induced Sleep Endoscopy and Hypoglossal Nerve Stimulation Outcomes: A Multicenter Cohort Study

OBJECTIVES/HYPOTHESIS

To determine the association between findings of blinded reviews of preoperative drug-induced sleep endoscopy (DISE) and outcomes of hypoglossal nerve stimulation (HNS) for obstructive sleep apnea (OSA).

STUDY DESIGN

Cohort study.

METHODS

A retrospective, multicenter cohort study of 343 adults who underwent treatment of OSA with HNS from 10 academic medical centers was performed. Preoperative DISE videos were scored by four blinded reviewers using the VOTE Classification and evaluation of a possible primary structure contributing to airway obstruction. Consensus DISE findings were examined for an association with surgical outcomes based on therapy titration polysomnogram (tPSG). Treatment response was defined by a decrease of ≥50% in the apnea-hypopnea index (AHI) to <15 events/hour.

RESULTS

Study participants (76% male, 60.4 ± 11.0 years old) had a body mass index of 29.2 ± 3.6 kg/m² . AHI decreased (35.6 ± 15.2 to 11.0 ± 14.1 events/hour; P < .001) on the tPSG, with a 72.6% response rate. Complete palate obstruction (vs. none) was associated with the greatest difference in AHI improvement (-26.8 ± 14.9 vs. -19.2 ± 12.8, P = .02). Complete (vs. partial/none) tongue-related obstruction was associated with increased odds of treatment response (78% vs. 68%, P = .043). Complete (vs. partial/none) oropharyngeal lateral wall-related obstruction was associated with lower odds of surgical response (58% vs. 74%, P = .042).

CONCLUSIONS

The DISE finding of primary tongue contribution to airway obstruction was associated with better outcomes, whereas the opposite was true for the oropharyngeal lateral walls. This study suggests that the role for DISE in counseling candidates for HNS extends beyond solely for excluding complete concentric collapse related to the velum.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:1676-1682, 2021.

Tolerance of Continuous Positive Airway Pressure After Sinonasal Surgery

OBJECTIVES/HYPOTHESIS

For patients with obstructive sleep apnea (OSA) undergoing sinonasal surgery, there is a lack of consensus on the risk and appropriate postoperative use of continuous positive airway pressure (CPAP). The aim of this study was to assess the tolerability of restarting CPAP on postoperative day one.

STUDY DESIGN

Prospective cohort study.

METHODS

A prospective study on patients with OSA on CPAP who required a septoplasty/turbinectomy and/or functional endoscopic sinus surgery (FESS) was performed. Data from the memory card of a patient's CPAP machine and subjective information were obtained on the day of surgery and at scheduled follow-up visits. All subjects were instructed to restart CPAP on the first postoperative night.

RESULTS

A total of 14 patients were analyzed; nine underwent FESS and five had a septoplasty/turbinectomy. There were no postoperative complications encountered. The only significant change in the first postoperative week was a reduction in the percentage of nights used over 4 hours (P < .05). By the third postoperative visit, average 22-item Sino-Nasal Outcome Test, Nasal Obstruction Symptom Evaluation, and CPAP tolerance scores improved from preoperative values. CPAP pressures, residual apnea-hypopnea index, and number of hours and mean percentage of nights used remained stable throughout the study period.

CONCLUSIONS

Both quality-of-life and CPAP outcomes improved or remained the same when restarting CPAP immediately postoperatively. Combined with a lack of significant complications, this study suggests that CPAP is well-tolerated when restarted the day after a septoplasty/turbinectomy or FESS.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E1013-E1018, 2021.

Straws Don't Suck: Are Straws Dangerous after Endoscopic Skull Base Surgery?

Objective Patients undergoing endoscopic endonasal surgery have historically been restricted from using straws postoperatively, due to the concern that this activity generates negative pressure. The objective of this study is to evaluate the pressure dynamics in the sinonasal cavity associated with the use of a straw.

Methods Intracranial pressure catheters were placed in the nasal cavity of 20 healthy individuals. Pressure measurements were then recorded while participants drank liquids of different viscosities from a cup and from a straw. Measurements were recorded with and without subjects occluding their nose to simulate postoperative nasal obstruction.

Results The average pressure in the nasal cavity while drinking water from a cup was −0.86 cmH2O, from a straw was −1.09 cmH2O, and while occluding the nose and using a straw was −0.81 cmH2O. The average pressure in the nasal cavity while drinking a milkshake from a cup was −0.98 cmH2O, from a straw was −1.88 cmH2O, and while occluding the nose and using a straw was −1.37 cmH2O. There was no statistically significant difference in pressure measurements when comparing either task or consistency (p > 0.05).

Conclusion Straw use is not associated with the generation of significant negative pressure in the nasal cavity. The pressure generated when drinking from a straw is not significantly different from that of drinking from a cup. This data suggest that straw use may be safe for patients following endoscopic skull base surgery, but further investigation is warranted.

Qualitative Assessment of the Effect of Continuous Positive Airway Pressure on the Nasal Cavity

BACKGROUND

For patients with obstructive sleep apnea (OSA), there is a lack of knowledge regarding the impact of continuous positive airway pressure (CPAP) on the nasal cavity. There is a significant need for evidence-based recommendations regarding the appropriate use of CPAP following endoscopic sinus and skull base surgery.

OBJECTIVE

The goal of this study is to translate a previously developed cadaveric model for evaluating CPAP pressures in the sinonasal cavity by showing safety in vivo and quantifying the effect of positive pressurized air flow on the nasal cavity of healthy individuals where physiologic effects are at play.

METHODS

A previously validated cadaveric model using intracranial sensor catheters has proved to be a reliable technique for measuring sinonasal pressures. These sensors were placed in the nasal cavity of 18 healthy individuals. Pressure within the nose was recorded at increasing levels of CPAP.

RESULTS

Overall, nasal cavity pressure was on average 85% of delivered CPAP. The amount of pressure delivered to the nasal cavity increased as the CPAP increased. The percentage of CPAP delivered was 77% for 5 cmH₂O and increased to 89% at 20 cmH₂O. There was a significant difference in mean intranasal pressures between all the levels of CPAP except 5 cmH₂O and 8 cmH₂O (P < .001).

CONCLUSION

On average, only 85% of the pressure delivered by CPAP is transmitted to the nasal cavity. Higher CPAP pressures delivered a greater percentage of pressurized air to the nasal cavity floor. Our results are comparable to the cadaver model, which demonstrated similar pressure delivery even in the absence of anatomic factors such as lung compliance, nasal secretions, and edema. This study demonstrates the safety of using sensors in the human nasal cavity. This technology can also be utilized to evaluate the resiliency of various repair techniques for endoscopic skull base surgery with CPAP administration.

Dysfunctional hypoglossal nerve stimulator after electrical cardioversion: A case series

OBJECTIVES/HYPOTHESIS

Upper airway stimulation has demonstrated marked improvements in apnea-hypopnea index, oxygen desaturation index, and quality-of-life measures in patients with moderate to severe obstructive sleep apnea (OSA) who cannot tolerate continuous positive airway pressure. Cardiac arrhythmias are common in patients with OSA and can require electrical cardioversion. We describe the first four reported cases of hypoglossal nerve stimulator (HGNS) dysfunction after electrical cardioversion and illustrate our operative approach to device troubleshooting and repair.

STUDY DESIGN

Retrospective case series.

METHODS

A retrospective review of 201 HGNS implantations performed at two academic institutions revealed four cases of HGNS device dysfunction after electrical cardioversion requiring surgical revision. Preoperative and postoperative device performance metrics and electrical cardioversion specifications were retrospectively assessed and compiled for this case series. The senior authors (R.J.S., M.S.B.) detail operative planning and approach for HGNS implantable pulse generator (IPG) replacement.

RESULTS

At least two patients with HGNS device dysfunction had received cardioversion via anterolateral electrode pad placement. Three patients had received multiple shocks. All four patients experienced a change in device functionality or complete cessation of functionality after electrocardioversion. Operatively, each patient required replacement of the IPG, with subsequent intraoperative interrogation revealing proper device functionality.

CONCLUSION

Counseling for patients with HGNS undergoing external electrical cardioversion should include possible device damage and need for operative replacement. Anteroposterior electrode pad placement should be considered for patients with HGNS who require electrocardioversion. Operative replacement of an HGNS system damaged by electrocardioversion begins with IPG replacement and intraoperative device interrogation.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:1949-1953, 2019.

Tubeless tracheotomy for survival airway surgery in the leporine model

OBJECTIVES/HYPOTHESIS

The ideal animal experimental tracheostomy technique is one that is 1) safe and easy to perform, 2) requires no tracheostomy tube, and 3) requires minimal cleaning or suctioning to maintain patency. The leporine model for airway injury has been well established and offers an inexpensive and practical animal model for experimental evaluation. However, previous research has demonstrated a high mortality rate with survival airway surgery in rabbits. This study demonstrates the feasibility of airway management in the leporine model using a simple maturing suture tracheostomy that avoids a tracheostomy tube.

STUDY DESIGN

Tracheostomy was performed in six New Zealand white rabbits in the setting of survival surgery over a 2-week study period.

METHODS

A vertical tracheal incision was made from the second to the sixth tracheal ring. The anterior portion of the tracheal rings was removed and the skin surrounding the stoma was sutured down to the tracheal wall. The lateral tracheal wall was then suspended to the soft tissue in the lateral neck.

RESULTS

All six rabbits survived the study period with minimal care and maintained stoma patency until sacrifice. Granulation tissue and edema were noted during the first week and largely resolved by the second week. An average of 5-mm-diameter stoma was measured 14 days after surgery without intraluminal stenosis or laryngeal edema.

CONCLUSIONS

This method meets the defined criteria for the ideal experimental tracheostomy, demonstrating potential benefit in a laryngotracheal stenosis model and a rabbit model of evoked phonation.

The use of a covered stent in carotid blowout syndrome

Rupture of the extracranial carotid arteries or their major branches is known as carotid blowout syndrome (CBS). CBS is a well-recognized complication of cancer of the head and neck and subsequent radiation therapy. A few treatment modalities are available, including open ligation and different endovascular techniques, but questions regarding both the immediate and delayed complications of these procedures persist. In this case report, we describe the management of acute CBS in a 54-year-old man who had previously been treated for follicular thyroid carcinoma. The patient was hemorrhaging from a pseudoaneurysm of the left common carotid artery. A self-expanding polytetrafluoroethylene (Teflon) -covered stent was successfully deployed endovascularly, and this resulted in cessation of the bleeding and restoration of flow through the vessel. We examine the covered-stent approach to treating acute CBS, and we discuss other treatment approaches that have been described in the literature.

Cervical Discitis and Epidural Abscess After Tonsillectomy

Approximately 6 weeks after an uncomplicated tonsillectomy for chronic tonsillitis, a 37-year-old woman presented to our emergency department with complaints of odynophagia and cervical pain persistent since surgery. Computed tomographic and magnetic resonance imaging revealed cervical spinal osteomyelitis with epidural abscess at C2 to 3. The patient underwent treatment with intravenous antibiotics, operative debridement, and cervical spinal stabilization. She recovered with no neurologic deficit.

CONCLUSIONS

Significant infectious complications of tonsillectomy are uncommon, and cervical spinal osteomyelitis and epidural abscess are exceptionally rare occurrences. In the presence of prolonged pain and dysphagia, imaging can be considered to evaluate for such sequelae.

Vagal paraganglioma: the Jefferson experience

Vagal paraganglioma is a rare tumor of neural crest origin. Although the literature is in agreement with regard to epidemiology, diagnosis, and tumor biology, there is some controversy over treatment modalities for these patients. We performed a nonrandomized retrospective study in a large single-institution series of patients (n = 19) in whom vagal paraganglioma was diagnosed. General statistics included age, male/female ratio, tumor size, and duration of follow-up. Other variables such as signs and symptoms at presentation, family history, multicentricity, metastatic disease, and secretion of catecholamines were included. CT scan, MRI, and angiography were used in combination for diagnostic purposes as well as for treatment planning. Preoperative embolization was performed in 5 of the more recently treated patients. Current issues regarding the use of preoperative embolization and choice of surgical approach were analyzed. In this article the possibility and sequela of vagus nerve-sparing procedures will be presented. Operative complications and postoperative morbidity related to cranial neuropathies will be discussed. The rationale for performing adjunct procedures, including cricopharyngeal myotomy and vocal fold medialization, to facilitate the rehabilitation of patients with postoperative cranial nerve deficits will be given. Our findings and recommendations will be compared with currently accepted treatment protocols in conjunction with a review of the literature.