Palate shape is associated with Unilateral Hypoglossal Nerve Stimulation Outcomes

OBJECTIVE

The aim was to determine the potential association between palate shape and unilateral hypoglossal nerve stimulation (HNS) outcomes.

METHODS

Preoperative drug-induced sleep endoscopy (DISE) videos were reviewed and scored by 3 blinded reviewers to determine airway narrowing at the hard-soft palate junction (HP), soft palate genu, and inferior velum, as described by Woodson (2014). Scoring was as follows: 1-open airway, 2-narrow, 3-severe narrowing. Overall palate shape (oblique, intermediate, or vertical) was determined based on prior criteria. Successful surgical treatment was defined by the HNS titration polysomnogram as a reduction of ≥50% in the apnea-hypopnea index (AHI) to <15 events/h.

RESULTS

Of 332 adults, the majority was male (77%) with an average BMI of 29.2 ± 3.6 kg/m2 . Overall success rate was 73%. Success rate was lower in patients with vertical palate shape compared with the other shapes (56% vs. 75%, p = 0.029). HP score 3 compared with scores 2 and 1 was associated with lower success rates (60% vs. 76%, p = 0.028), but genu and velum scores were not associated with outcomes. Patients with both HP score 3 and complete oropharyngeal lateral wall-related obstruction had notably worse outcomes (22% vs. 74%, p = 0.026). HP score 3 (OR 0.45, 95%CI 0.22-0.92) and vertical palate shape (OR 0.33, 95%CI 0.15-0.78) were independently associated with lower odds of surgical response after adjustment for DISE findings, age, gender, and BMI.

CONCLUSION

Vertical palate shape and narrowing at the hard-soft palate junction are independently associated with lower HNS surgical success rates.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:981-986, 2024.

Objective Pharyngeal Phenotyping in Obstructive Sleep Apnea With High-Resolution Manometry

OBJECTIVE

Drug-induced sleep endoscopy (DISE) is a commonly used diagnostic tool for surgical procedural selection in obstructive sleep apnea (OSA), but it is expensive, subjective, and requires sedation. Here we present an initial investigation of high-resolution pharyngeal manometry (HRM) for upper airway phenotyping in OSA, developing a software system that reliably predicts pharyngeal sites of collapse based solely on manometric recordings.

STUDY DESIGN

Prospective cross-sectional study.

SETTING

An academic sleep medicine and surgery practice.

METHODS

Forty participants underwent simultaneous HRM and DISE. A machine learning algorithm was constructed to estimate pharyngeal level-specific severity of collapse, as determined by an expert DISE reviewer. The primary outcome metrics for each level were model accuracy and F1-score, which balances model precision against recall.

RESULTS

During model training, the average F1-score across all categories was 0.86, with an average weighted accuracy of 0.91. Using a holdout test set of 9 participants, a K-nearest neighbor model trained on 31 participants attained an average F1-score of 0.96 and an average accuracy of 0.97. The F1-score for prediction of complete concentric palatal collapse was 0.86.

CONCLUSION

Our findings suggest that HRM may enable objective and dynamic mapping of the pharynx, opening new pathways toward reliable and reproducible assessment of this complex anatomy in sleep.

Supine Pharyngeal Width Is Associated With Complete Concentric Palatal Collapse During Drug-Induced Sleep Endoscopy and Hypoglossal Nerve Stimulator Outcomes

OBJECTIVE

Hypoglossal nerve stimulation (HNS) implantation in the US requires preoperative drug-induced sleep endoscopy (DISE) screening for complete concentric palatal collapse (CCC) to establish treatment candidacy. We hypothesized that supine pharyngeal width (SPW) in awake patients is associated with CCC and HNS therapy outcomes.

METHODS

Adults with moderate to severe obstructive sleep apnea underwent awake measurement of SPW followed by DISE screening for CCC. Eligible patients electing for HNS implantation underwent postoperative polysomnography per standard of care.

RESULTS

SPW was measured in 73 patients. For SPW >20 mm, the positive likelihood ratio for absence of CCC was 6.67 with pre- and post-test odds of 6.3 and 42.0, respectively. Postoperative PSG data were available from 31 of 44 (70.5%) patients subsequently implanted with HNS. Patients with SPW >20 mm had a greater rate of HNS response than those with SPW ≤20 (62 vs 30%; P < .05). Only SPW and BMI were significantly associated with CCC and HNS response in regression models.

CONCLUSION

In a retrospective cohort study, SPW was significantly associated with CCC and postoperative apnea-hypopnea index following HNS implantation. SPW may be a viable screening tool for HNS candidacy.

A Noninferiority Analysis of 3- vs 2-Incision Techniques for Hypoglossal Nerve Stimulator Implantation

OBJECTIVE

The only hypoglossal nerve stimulation (HNS) device available for US clinical use is implanted through 3 incisions. A recently proposed 2-incision modification moved the respiratory sensing lead from the fifth to the second intercostal space to eliminate the third lower chest incision. This study compared perioperative data and therapeutic outcomes between the techniques.

STUDY DESIGN

Noninferiority cohort analysis of a retrospective and prospective registry study.

SETTING

Tertiary care and community surgical centers.

METHODS

Patients with obstructive sleep apnea underwent HNS implantation via a modified 2-incision technique (I₂). A cohort previously implanted via the standard 3-incision technique (I₃) were 1:1 propensity score matched for a noninferiority analysis of postoperative outcomes.

RESULTS

There were 404 I₃ patients and 223 I₂ patients across 6 participating centers. Operative time decreased from 128.7 minutes (95% CI, 124.5-132.9) in I₃ patients to 86.6 minutes (95% CI, 83.7-97.6) in I₂ patients (P < .001). Postoperative sleep study data were available for 76 I₂ patients who were matched to I₃ patients. The change in apnea-hypopnea index between the cohorts was statistically noninferior (a priori noninferiority margin: 7.5 events/h; mean difference, 1.51 [97.5% CI upper bound, 5.86]). There were no significant differences between the cohorts for baseline characteristics, perioperative adverse event rates, or change in Epworth Sleepiness Score (P > .05).

CONCLUSION

In a multicenter registry, a 2-incision implant technique for a commercially available HNS device had a statistically noninferior therapeutic efficacy profile when compared with the standard 3-incision approach. The 2-incision technique is safe and effective for HNS implantation.

Ansa cervicalis stimulation increases pharyngeal patency in patients with obstructive sleep apnea

Hypoglossal nerve stimulation (HNS) is an alternative treatment option for obstructive sleep apnea (OSA) that reduces pharyngeal collapsibility, but HNS nonresponders 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. Our objective was to evaluate the effect of ACS on pharyngeal patency during expiration when the airway is most hypotonic. 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 (V̇e) were measured from endoscopy video with ImageJ and pneumotachometry, respectively. ACS significantly increased retropalatal cross-sectional area (CSA_RP) to 211% [159-263] of unstimulated CSA_RP (P < 0.05). Adding ACS to HNS increased CSA_RP from baseline by 341% [244-439] (P < 0.05), a 180% [133-227] increase over isolated HNS (P < 0.05). ACS increased V̇e from baseline by 177% [138-217] P < 0.05). Adding ACS to HNS increased V̇e by 254% [207-301], reflecting decreases in pharyngeal collapsibility. 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.NEW & NOTEWORTHY Ansa cervicalis stimulation (ACS) is a recently proposed neurostimulation mechanism for generating caudal pharyngeal traction that may benefit patients with obstructive sleep apnea. Here, we document endoscopic findings with ACS during drug-induced sleep endoscopy and additionally detail the effects of ACS on expiratory airflow, when the pharynx is known to be most hypotonic.

Artificial intelligence in sleep medicine: an American Academy of Sleep Medicine position statement

None

Sleep medicine is well positioned to benefit from advances that use big data to create artificially intelligent computer programs. One obvious initial application in the sleep disorders center is the assisted (or enhanced) scoring of sleep and associated events during polysomnography (PSG). This position statement outlines the potential opportunities and limitations of integrating artificial intelligence (AI) into the practice of sleep medicine. Additionally, although the most apparent and immediate application of AI in our field is the assisted scoring of PSG, we propose potential clinical use cases that transcend the sleep laboratory and are expected to deepen our understanding of sleep disorders, improve patient-centered sleep care, augment day-to-day clinical operations, and increase our knowledge of the role of sleep in health at a population level.

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.

Ultrasound Localization and Percutaneous Electrical Stimulation of the Hypoglossal Nerve and Ansa Cervicalis

OBJECTIVE

Hypoglossal nerve stimulation for obstructive sleep apnea (OSA) can be effective for appropriately selected patients, but current patient selection criteria are complex and still result in a proportion of nonresponders. Ansa cervicalis stimulation of the infrahyoid cervical strap muscles has recently been proposed as a new form of respiratory neurostimulation (RNS) therapy for OSA treatment. We hypothesized that percutaneous stimulation of both nerves in humans with temporary electrodes would make testing of the physiologic response to different RNS strategies possible.

STUDY DESIGN

Nonrandomized acute physiology study.

SETTING

Tertiary care hospital.

METHODS

Fifteen participants with OSA underwent ultrasonography and placement of percutaneous electrodes proximal to the medial division of the hypoglossal nerve and the branch of the ansa cervicalis innervating the sternothyroid muscle (ACST). Procedural success was documented in each participant, as were any failures or procedural complication.

RESULTS

The hypoglossal nerve was successfully localized in 15 of 15 (100%) participants and successfully stimulated in 13 of 15 (86.7%). The ACST was successfully localized in 15 of 15 (100%) participants and successfully stimulated in 14 of 15 (93.3%). Stimulation failure of the hypoglossal nerve was due to suboptimal electrode placement in 1 participant and electrode displacement in the other 2 cases. No complications occurred.

CONCLUSIONS

The hypoglossal nerve and ACST can be safely stimulated via percutaneous electrode placement. Larger trials of percutaneous stimulation may help to identify responders to different RNS therapies for OSA with temporary or permanent percutaneous electrodes. Techniques for electrode design, nerve localization, and electrode placement are described.

Stathmin as a surrogate marker of phosphatidylinositol-3-kinase pathway activity: Towards precision medicine in HPV-negative head & neck squamous cell carcinoma

In order to assess Stathmin as an immunohistochemical (IHC) indicator of phosphatidylinositol 3-kinase (PI3K) pathway activity in HPV-negative head & neck squamous cell carcinoma (HNSCC), we compared Stathmin IHC to expression of other pathway components. We also evaluated the relationship between Stathmin IHC and the mutational status of four key pathway genes. Finally, we ascertained whether Stathmin IHC correlates with tumor grade or primary site. Correlation exists between high Stathmin expression and high pAKT1 expression, indicating a role for Stathmin IHC as a marker of pathway activity. Our analysis did not show correlation between Stathmin IHC and mutation of the four genes evaluated. We also observed an association between high Stathmin expression and oropharyngeal primary site. Our results suggest utility of Stathmin IHC as an indicator of PI3K pathway activity, and thereby demonstrate potential relevance of Stathmin IHC in the context of HNSCC.

Artificial intelligence in sleep medicine: background and implications for clinicians

None

Polysomnography remains the cornerstone of objective testing in sleep medicine and results in massive amounts of electrophysiological data, which is well-suited for analysis with artificial intelligence (AI)-based tools. Combined with other sources of health data, AI is expected to provide new insights to inform the clinical care of sleep disorders and advance our understanding of the integral role sleep plays in human health. Additionally, AI has the potential to streamline day-to-day operations and therefore optimize direct patient care by the sleep disorders team. However, clinicians, scientists, and other stakeholders must develop best practices to integrate this rapidly evolving technology into our daily work while maintaining the highest degree of quality and transparency in health care and research. Ultimately, when harnessed appropriately in conjunction with human expertise, AI will improve the practice of sleep medicine and further sleep science for the health and well-being of our patients.

Evaluation of Hypoglossal Nerve Stimulation Treatment in Obstructive Sleep Apnea

Importance

Hypoglossal nerve stimulation is a treatment option for patients with obstructive sleep apnea unable to tolerate continuous positive airway pressure. This study evaluates demographic factors that may be associated with greater improvements in postoperative outcomes of interest.

Objective

To examine the association of hypoglossal nerve stimulation with obstructive sleep apnea severity, daytime sleepiness, and sleep-related quality of life.

Design, Setting, and Participants

Patient-level data were pooled from 3 prospective cohorts and 1 retrospective observational cohort comprising 584 adults with moderate to severe obstructive sleep apnea unable to tolerate or benefit from continuous positive airway pressure. The data were gathered from the Stimulation Therapy for Apnea Reduction Trial; a postmarket approval study conducted in Germany; the multicenter, international Adherence and Outcome of Upper Airway Stimulation for OSA Registry; and a retrospective cohort study from 2 sites in the United States.

Exposure

Hypoglossal nerve stimulation.

Main Outcomes and Measures

Severity of obstructive sleep apnea was the primary outcome. The apnea-hypopnea index (AHI) (<5, normal; 5-15, mild; 15-30, moderate, and >30, severe) and Epworth Sleepiness Scale (range, 0-24; score >10 indicates pathologic sleepiness) outcomes were available at 2 to 6 months from 2 cohorts (n = 398), at 12 months from 1 cohort (n = 126), and at both times from 1 cohort (n = 60). Sleep-related quality of life and oxygen saturation nadir data were collected where available. Linear mixed-effects models were constructed to examine associations between clinical variables and reported postoperative outcomes at 6 and 12 months with study included as a random effect.

Results

Of the 584 patients included in the study, 472 were men (80.8%); mean (SD) age was 58.5 (11.0) years. Greater improvement in the postoperative AHI was associated with a higher preoperative AHI (-0.74 events/h; 95% CI, -0.82 to -0.67), older patient age (-0.10 events/h; 95% CI, -0.20 to -0.00), and lower body mass index (0.52; 95% CI, 0.22-0.83). After adjusting for these variables and considering all patients in the analysis, the AHI was statistically higher at 12 months than at 6 months (3.24 events/h; 95% CI, 1.67-4.82 events/h).

Conclusions and Relevance

Hypoglossal nerve stimulation demonstrated clinically significant improvements in obstructive sleep apnea severity, daytime sleepiness, and sleep-related quality of life in this pooled cohort of patient-level results. Age, body mass index, and preoperative AHI appeared to be associated with treatment outcomes, and these variables may explain some of the difference between 2- to 6-month and 12-month outcomes.

Drug-Induced Sleep Endoscopy and Surgical Outcomes: A Multicenter Cohort Study

OBJECTIVE

To evaluate the association between findings of blinded reviews of preoperative drug-induced sleep endoscopy (DISE) examinations using the VOTE Classification and obstructive sleep apnea (OSA) surgical outcomes in a large multicenter, international cohort.

METHODS

Retrospective, multi-center cohort study of adults without tonsillar hypertrophy who underwent pharyngeal surgery for OSA. The study included only participants without enlarged tonsils. Four independent reviewers performed blinded review of preoperative DISE videos using the VOTE Classification system and scoring of a primary structure contributing to airway obstruction. DISE findings were examined for an association with surgical outcomes with univariate analyses and multiple regression.

RESULTS

Two hundred seventy-five study participants were included from 14 centers. Mean age was 51.4 ± 11.8 years, and body mass index was 30.1 ± 5.2 kg/m² . There was moderate interrater reliability (kappa = 0.40-0.60) for DISE findings. Oropharyngeal lateral wall-related obstruction was associated with poorer surgical outcomes (adjusted odds ratio (AOR) 0.51; 95% CI 0.27, 0.93). Complete tongue-related obstruction was associated with a lower odds of surgical response in moderate to severe OSA (AOR 0.52; 95% CI 0.28, 0.98), with findings that were similar but not statistically significant in other analyses. Surgical outcomes were not clearly associated with the degree and configuration of velum-related obstruction or the degree of epiglottis-related obstruction. Surgical response was associated with tonsil size and body mass index (inversely).

CONCLUSION

DISE findings concerning the oropharyngeal lateral walls and tongue may be the most important findings of this evaluation technique.

LEVEL OF EVIDENCE

2B Laryngoscope, 129:761-770, 2019.

Surgical trainees and powered-drill use do not affect type I tympanoplasty hearing outcomes

The purposes of this study were to determine if use of a powered drill or trainee involvement during tympanoplasty is associated with a decline in sensorineural hearing, as well as to examine whether trainee involvement affected tympanic membrane (TM) closure rates. This study was a chart review (February 2006 to October 2011) of 172 pediatric otolaryngology patients undergoing type I tympanoplasty for TM perforation of any etiology at a tertiary-care pediatric otolaryngology practice. Data collected included air conduction (AC) at 250 to 8,000 Hz, speech reception thresholds, bone conduction (BC) at 500 to 4,000 Hz, and air-bone gap (ABG) at 500 to 4,000 Hz. Rates of surgical success did not change significantly if a trainee assisted during surgery (69.6% with an assistant vs. 77.4% without; p = 0.297). AC hearing was not found to be significantly different between the two groups preoperatively or postoperatively at 250, 500, 1,000, 2,000, 4,000, or 8,000 Hz (p > 0.05). There were no significant differences in AC hearing outcomes between patients in whom a surgical drill was used and those in whom no drill was used (p > 0.05). BC and ABG did not change significantly at any frequency (p > 0.05). In conclusion, no correlation between high-frequency hearing loss and use of a powered drill for canalplasty during type I tympanoplasty was found in this pediatric population. No significant difference was found in surgical success rates or AC hearing outcomes when a surgical trainee was present.

Upper Airway Stimulation for OSA: Early Adherence and Outcome Results of One Center

OBJECTIVE

To review outcome measures and objective adherence data for patients treated with hypoglossal nerve stimulation (HNS) therapy for moderate to severe obstructive sleep apnea (OSA).

STUDY DESIGN

Case series with chart review.

SETTING

Academic sleep medicine center.

SUBJECTS AND METHODS

The first 20 implanted patients to complete postoperative sleep laboratory testing were assessed. All patients had moderate to severe OSA, were unable to adhere to positive pressure therapy, and met previously published inclusion criteria for the commercially available implantable HNS system. Data included demographics, body mass index (BMI), apnea-hypopnea index (AHI), Epworth Sleepiness Score (ESS), nightly hours of device usage, and procedure- and therapy-related complications.

RESULTS

Mean age was 64.8 ± 12.0 years, with 50% female. Mean BMI was unchanged postoperatively (26.5 ± 4.2 to 26.8 ± 4.5 kg/m(2); P > .05). Mean AHI (33.3 ± 13.0 to 5.1 ± 4.3; P < .0001) and mean ESS (10.3 ± 5.2 to 6.0 ± 4.4; P < .01) decreased significantly. Seventy percent (14/20) of patients achieved a treatment AHI <5, 85% (17/20) an AHI <10, and 95% (19/20) an AHI <15. Average stimulation amplitude was 1.89 ± 0.50 V after titration. Adherence monitoring via device interrogation showed high rates of voluntary device use (mean 7.0 ± 2.2 h/night).

CONCLUSION

For a clinical and anatomical subset of patients with OSA, HNS therapy is associated with good objective adherence, low morbidity, and improved OSA outcome measures. Early results at one institution suggest that HNS therapy can be implemented successfully into routine clinical practice, outside of a trial setting.

Drug-Induced Sedation Endoscopy in the Evaluation of OSA Patients with Incomplete Oral Appliance Therapy Response

Objective

To use drug-induced sedation endoscopy (DISE) to identify locations and patterns of residual collapse in patients with obstructive sleep apnea (OSA) with incomplete response to oral appliance therapy (OAT).

Study Design

Case series with chart review.

Setting

Academic multidisciplinary sleep practice.

Subjects and Methods

Thirty-five consecutively screened adult patients with OSA with continuous positive airway pressure (CPAP) intolerance and incomplete response to OAT (apnea-hypopnea index [AHI] >15 or AHI >5 with persistent subjective symptoms) who underwent DISE with and without the oral appliance. Data collected included demographics, body mass index, polysomnography data, and management decisions after DISE. Each DISE video pair was retrospectively scored using the VOTE classification system by the same blinded reviewer (R.J.S.).

Results

All patients had multilevel airway collapse at baseline. The palate was the most common location of OAT failure. Fifteen (42.9%) had persistent collapse of the velum during DISE with OAT, and 7 (20%) had persistent collapse of the epiglottis. Twenty-three (65.7%) patients were offered targeted surgery based on DISE findings to augment OAT effectiveness. Twenty (57.1%) patients underwent additional medical therapy such as OAT adjustment or cervical positional therapy. Mean AHI was reduced from 37.4 at baseline, to 16.4 with OAT ( P < .01), and to 10.7 after post-DISE intervention ( P < .78).

Conclusion

In patients with incomplete response to OAT, DISE with and without the appliance can identify residual anatomical locations of collapse, which may direct additional medical and surgical treatment options to augment OAT effectiveness. Further work is needed to determine if DISE affects outcomes.

Conventional and 3-Dimensional Computerized Tomography in Eagle's Syndrome, Glossopharyngeal Neuralgia, and Asymptomatic Controls

OBJECTIVE

Eagle's syndrome (ES) is an aggregate of symptoms, including recurrent throat pain, foreign body sensation, dysphagia, or facial pain related to an elongated styloid process (SP). It resembles glossopharyngeal neuralgia and has been linked to irritation of the glossopharyngeal nerve. This study was designed to determine whether computerized tomography (CT) imaging of the stylohyoid chain (SHC) differs between asymptomatic controls (ACs), patients with glossopharyngeal neuralgia (GN), and patients with ES.

STUDY DESIGN

Case series with chart review.

SETTING

Tertiary otolaryngology practice.

SUBJECTS AND METHODS

Conventional and 3-dimensional CT reconstructions of the SHC were reviewed for 10 ES, 17 GN, and 30 AC patients. Demographic and clinical symptom data were recorded. Anatomic data collected from CT scans included length of the ossified SP, anterior-posterior and medial-lateral styloid process angulation, ossification pattern of the SHC, and minimum distances between the SP tip, the internal carotid artery, and the tonsillar fossa.

RESULTS

The average distance from the SP tip to the tonsillar fossa was significantly shorter in ES (12.7 mm) compared with GN (21.4 mm; P = .027) or AC (24.8 mm; P < .0005) patients. No other variables were significantly different between groups, including average SP length (ES: 48.0 vs GN: 40.3 vs AC: 40 mm; P > .05).

CONCLUSION

The SP was significantly closer to the tonsillar fossa in patients with ES compared with ACs. No significant differences were found in other measures. Distance to the tonsillar fossa may be a more appropriate diagnostic criterion for ES than SP length and may contribute to the pathophysiology of ES.

Frequency-Specific Hearing Outcomes after Use of a Powered Drill in Pediatric Type I Tympanoplasty

Objectives:

(1) Describe factors related to frequency-specific hearing outcomes after type I tympanoplasty in pediatric patients. (2) Describe the effect of powered bone drilling on frequency-specific hearing outcomes after type I tympanoplasty.

Methods:

Retrospective medical chart review (February 2006 to October 2011) of 492 consecutive pediatric otolaryngology patients undergoing type I tympanoplasty for tympanic membrane (TM) perforation of any etiology at a tertiary-care pediatric otolaryngology practice. Data collected included air conduction at 250 to 8000 Hz, speech reception thresholds, bone conduction at 500 to 4000 Hz, and air-bone gap at 500 to 4000 Hz. Demographic data obtained included sex, age, size, mechanism, location of perforation, and operative repair technique, as well as the use of a powered bone drill during surgery.

Results:

A downtrend in sensorineural hearing at 2000 and 4000 Hz was noted with the use of a powered drill during surgery, although no significant difference in sensorineural hearing or air-bone gap was detected at 500, 1000, 2000, or 4000 Hz ( P > .05). No significant change was detected in conductive hearing at 1000, 2000, 4000 Hz, or 8000 Hz ( P > .05). Significant improvement was noted in lower-frequency conductive hearing at 250 and 500 Hz ( P < .001).

Conclusions:

No correlation between high-frequency hearing loss and use of a powered drill during type I tympanoplasty was found in this pediatric population. Surgery was found to significantly improve conductive hearing at 200 and 500 Hz. Based on these results, use of a powered bone drill is not contraindicated during type I tympanoplasty.

3D-CT Comparison of the Stylohyoid Chain in Eagle’s Syndromes, Glossopharyngeal Neuralgia, and Asymptomatic Controls

Objectives:

(1) Describe 3-dimensional (3D) computed tomography (CT) anatomic features of the stylohyoid chain in Eagle’s syndrome patients (ES), glossopharyngeal neuralgia patients (GPN), and normal asymptomatic controls (NC). (2) Understand 3D-CT features findings associated with Eagle’s syndrome.

Methods:

Retrospective chart review from November 2000 to November 2013. 3D shaded surface display CT reconstructions of the stylohyoid chain were generated for 10 ES patients, 16 GPN, and 15 NC patients. Demographic and clinical symptom data were recorded. Anatomic data collected from CT scans included: length of ossified styloid process, anterior-posterior (APA) and medial-lateral (MLA) styloid process angulation, ossification pattern of the stylohyoid chain, and minimum distances between the styloid process and the internal carotid artery, C1 transverse process, and tonsillar fossa.

Results:

The average distance from the styloid process tip to the tonsillar fossa was found to be significantly shorter in ES patients (12.7 mm) compared with GPN (21.4 mm; P < .05) or NC (24.8 mm; P < .001) patients. No other measured variables were found to be significantly different between groups, including average styloid process length (ES: 48.0 vs GPN: 40.3 vs NC: 40 mm; P > .05).

Conclusions:

The styloid process was found to be significantly closer to the tonsillar fossa in ES patients as compared to GPN and NC patients by 3D-CT reconstructions. No significant differences were found in other measures, including styloid process length. Distance to the tonsillar fossa may be a more appropriate diagnostic criterion for ES than styloid process length, and may contribute to the pathophysiology of ES.

Drug-Induced Sleep Endoscopy Informs Management of Obstructive Sleep Apnea after Incomplete Mandibular Advancement Device Response

Objectives:

(1) Understand that half of obstructive sleep apnea (OSA) patients failing positive airway pressure (PAP) attempt mandibular advancement device (MAD) therapy but still suffer from residual disease. (2) Describe how drug-induced sleep endoscopy (DISE) evaluates anatomical patterns of obstruction under conditions that mimic sleep and aids management in patients with incomplete response to MAD.

Methods:

A review of 35 consecutive adult OSA patients, with continuous positive airway pressure intolerance and incomplete response to MAD therapy (apnea-hypopnea index [AHI] >15 or AHI >5 with persistent subjective symptoms), who underwent DISE with and without the MAD between 12/2010 and 8/2013. Data collected included demographics, body mass index (BMI), Epworth Sleepiness Score (ESS), polysomnography data, and management decisions after DISE. Each DISE video was retrospectively scored using the VOTE classification system by the same blinded reviewer (R.J.S.).

Results:

All patients had multilevel airway obstruction during baseline DISE. 32 (91.4%) obstructed in the velopharynx despite MAD use. 26 (74.3%) patients were recommended to undergo targeted surgery based on DISE findings with 21 (60%) completing it. Nineteen (54.3%) underwent additional medical therapy such as MAD or PAP adjustment. Twelve (34.3%) were treated with surgical and medical therapy. Subjective and objective outcomes were significantly improved in 15 patients with outcome data currently available (mean AHI 39.3 to 10.7, P < .01; ESS 11.2 to 6.25, P < .01).

Conclusions:

In patients with incomplete response to MAD therapy, DISE with and without the MAD provides informs management decisions regarding additional medical or surgical options to augment the effectiveness of the MAD.

Frequency-specific hearing outcomes in pediatric type I tympanoplasty

IMPORTANCE

Middle ear disease is the primary cause of hearing loss in children and has a significant impact on language development and academic performance. Multiple prognostic factors have previously been examined, but there is little published data regarding frequency-specific hearing outcomes.

OBJECTIVE

To examine the relationship between type I tympanoplasty in a pediatric population and frequency-specific hearing changes, as well as the relationship between several prognostic factors and graft retention.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective medical chart review (February 2006 to October 2011) of 492 consecutive pediatric otolaryngology patients undergoing type I tympanoplasty for tympanic membrane (TM) perforation of any etiology at a tertiary-care pediatric otolaryngology practice.

INTERVENTIONS

Type I tympanoplasty.

MAIN OUTCOMES AND MEASURES

Preoperative and postoperative audiometric data were collected for patients undergoing successful TM repair. It was hypothesized before data collection that conductive hearing would improve at all frequencies with no significant change in sensorineural hearing. Data collected included air conduction at 250 to 8000 Hz, speech reception thresholds, bone conduction at 500 to 4000 Hz, and air-bone gap at 500 to 4000 Hz. Demographic data obtained included sex, age, size, mechanism, location of perforation, and operative repair technique.

RESULTS

Of 492 patients, 320 were excluded; results were thus examined for 172 patients. Surgery was successful for 73.8% of patients. Perforation size was significantly associated with repair success (mean [SD] surgical success rate of 38.6% [15.3%] vs surgical failure rate of 31.4% [15.0%]; P < .01); however, mean (SD) age (9.02 [3.89] years [surgical success] vs 8.52 [3.43] years [surgical failure]; P > .05) and repair technique (medial [73.08%] vs lateral [76.47%] graft success; P > .99) were not. Air conduction significantly improved from 250 to 2000 Hz (P < .001), did not significantly improve at 4000 Hz (P = .08), and there was a nonsignificant decline at 8000 Hz (P = .12). Speech reception threshold significantly improved (20 vs 15 dB; P < .001).

CONCLUSIONS AND RELEVANCE

This large review found an association of TM perforation size with surgical success and an improvement in speech reception threshold, air conduction at 250 to 2000 Hz, air-bone gap at 500 to 2000 Hz, and worsening bone conduction at 4000 Hz. Patients with high-frequency hearing loss due to TM perforation should not anticipate significant recovery from type I tympanoplasty. Hearing loss at higher frequencies may require postoperative hearing rehabilitation.

Multi-tissue microarray analysis identifies a molecular signature of regeneration

The inability to functionally repair tissues that are lost as a consequence of disease or injury remains a significant challenge for regenerative medicine. The molecular and cellular processes involved in complete restoration of tissue architecture and function are expected to be complex and remain largely unknown. Unlike humans, certain salamanders can completely regenerate injured tissues and lost appendages without scar formation. A parsimonious hypothesis would predict that all of these regenerative activities are regulated, at least in part, by a common set of genes. To test this hypothesis and identify genes that might control conserved regenerative processes, we performed a comprehensive microarray analysis of the early regenerative response in five regeneration-competent tissues from the newt Notophthalmus viridescens. Consistent with this hypothesis, we established a molecular signature for regeneration that consists of common genes or gene family members that exhibit dynamic differential regulation during regeneration in multiple tissue types. These genes include members of the matrix metalloproteinase family and its regulators, extracellular matrix components, genes involved in controlling cytoskeleton dynamics, and a variety of immune response factors. Gene Ontology term enrichment analysis validated and supported their functional activities in conserved regenerative processes. Surprisingly, dendrogram clustering and RadViz classification also revealed that each regenerative tissue had its own unique temporal expression profile, pointing to an inherent tissue-specific regenerative gene program. These new findings demand a reconsideration of how we conceptualize regenerative processes and how we devise new strategies for regenerative medicine.

Fluorescent whole-mount method for visualizing three-dimensional relationships in intact and regenerating adult newt spinal cords

Adult newts have the remarkable ability to regenerate their spinal cords after a complete transection injury. To understand this process, we have developed a method for visualizing the cellular and molecular events during regeneration in whole-mount preparations using fluorescent probes (streptavidins and antibodies) and confocal microscopy. This method was optimized by varying parameters associated with fixation, tissue trimming, fluorescent probe penetration, and clearing and represents a significant advance in our ability to observe the intact and regenerating newt spinal cord. These methods should also be widely applicable to the study of other newt tissues and adult tissues from other model systems.

Novel IRF6 mutations in Honduran Van der Woude syndrome patients

Van der Woude syndrome (VWS) is an autosomal dominant inherited disease characterized by lower lip pits, cleft lip and/or cleft palate. Missense, nonsense and frameshift mutations in IRF6 have been revealed to be responsible for VWS in European, Asian, North American and Brazilian populations. However, the mutations responsible for VWS have not been studied in Central American populations. Here, we investigated the role of IRF6 in patients with VWS in a previously unstudied Honduran population. IRF6 mutations were identified in four out of five VWS families examined, which strongly suggests that mutations in IRF6 are responsible for VWS in this population. We reported three novel mutations and one previously described mutation. In the first family, a mother and daughter both exhibited a p.N88I mutation in the DNA-binding region of IRF6 that was not present in unaffected family members. In the second, we found a unique p.K101QfsX15 mutation in the affected patient, leading to a frameshift and early stop codon. In the third, we identified a p.Q208X mutation occurring in exon 6. In the fourth, we found a nonsense mutation in exon 9 (p.R412X), previously described in Brazilian and Northern European populations. In the fifth, we did not identify any unique exonic missense, nonsense or frameshift mutations. This study reports the first cases of IRF6 mutations in VWS patients in a Central American population, further confirming that the causal link between IRF6 and VWS is consistent across multiple populations.

Meningeal cells and glia establish a permissive environment for axon regeneration after spinal cord injury in newts

Background

Newts have the remarkable ability to regenerate their spinal cords as adults. Their spinal cords regenerate with the regenerating tail after tail amputation, as well as after a gap-inducing spinal cord injury (SCI), such as a complete transection. While most studies on newt spinal cord regeneration have focused on events occurring after tail amputation, less attention has been given to events occurring after an SCI, a context that is more relevant to human SCI. Our goal was to use modern labeling and imaging techniques to observe axons regenerating across a complete transection injury and determine how cells and the extracellular matrix in the injury site might contribute to the regenerative process.

Results

We identify stages of axon regeneration following a spinal cord transection and find that axon regrowth across the lesion appears to be enabled, in part, because meningeal cells and glia form a permissive environment for axon regeneration. Meningeal and endothelial cells regenerate into the lesion first and are associated with a loose extracellular matrix that allows axon growth cone migration. This matrix, paradoxically, consists of both permissive and inhibitory proteins. Axons grow into the injury site next and are closely associated with meningeal cells and glial processes extending from cell bodies surrounding the central canal. Later, ependymal tubes lined with glia extend into the lesion as well. Finally, the meningeal cells, axons, and glia move as a unit to close the gap in the spinal cord. After crossing the injury site, axons travel through white matter to reach synaptic targets, and though ascending axons regenerate, sensory axons do not appear to be among them. This entire regenerative process occurs even in the presence of an inflammatory response.

Conclusions

These data reveal, in detail, the cellular and extracellular events that occur during newt spinal cord regeneration after a transection injury and uncover an important role for meningeal and glial cells in facilitating axon regeneration. Given that these cell types interact to form inhibitory barriers in mammals, identifying the mechanisms underlying their permissive behaviors in the newt will provide new insights for improving spinal cord regeneration in mammals.

The association between interferon regulatory factor 6 (IRF6) and nonsyndromic cleft lip with or without cleft palate in a Honduran population

OBJECTIVES/HYPOTHESIS

Interferon regulatory factor 6 (IRF6), the gene that causes van der Woude syndrome (VWS), is a candidate gene for nonsyndromic cleft lip with or without cleft palate (NSCLP) because a number of studies have supported an association between NSCLP and single nucleotide polymorphisms (SNPs) in IRF6 in several populations. This project investigated the contribution of IRF6 to NSCLP in the Honduran population, a previously unstudied group with a high prevalence of NSCLP.

STUDY DESIGN

Family-based joint linkage and association study.

METHODS

A set of five SNPs in and around IRF6 previously reported to be associated with NSCLP were tested for association with NSCLP in 276 affected and unaffected Honduran individuals from 59 families with at least two members affected by clefting and at least one member with confirmed NSCLP.

RESULTS

We observed support of linkage for three SNPs-rs1856161, rs2235371, and rs2235377-under a dominant model (log of odds [LODs] = 1.97, 1.56, 1.73, respectively). Subsequent single-point, haplotype, and joint linkage and association analyses continued to support the association with NSCLP (P < or = .05) at these three SNPs. When analysis was restricted to NSCLP cases, excluding cleft palate only cases, support for association strengthened.

CONCLUSIONS

This is the first study to demonstrate that three candidate SNPs within IRF6 are significantly associated with NSCLP in the Honduran population, providing the first genetic clue to NSCLP observed in the Honduran population and confirming findings from populations in other parts of the world. Further studies are needed to identify the putative variant(s).