Defining the Shape of the Mylohyoid Muscle: A Morphometric Imaging Study

OBJECTIVES

Implantable hypoglossal nerve stimulation (HNS) therapy is an evolving therapeutic alternative for patients with refractory obstructive sleep apnea (OSA). The muscular anatomy of this region has implications for surgical access through this zone as well as positioning and anchoring of hardware in this area. The purpose of this study was to radiologically describe the topography of the mylohyoid muscle and adjacent structures across a wide age spectrum.

METHODS

We retrospectively evaluated computed tomography scans of the neck in 102 patients who were imaged for reasons unrelated to the floor of mouth or submental space. Patients with prior surgery or pathology in the area of interest were excluded. Fourteen relevant muscle measurements were made on a midline sagittal image and a coronal image positioned at the midpoint between the hyoid bone and the mandible.

RESULTS

We included 49 men and 53 women with an average age of 44 years (range 19-70). The average mylohyoid length was 42 mm; the average distance between the anterior digastric bellies was 17 mm. The average angle of the central mylohyoid was 174° in the sagittal plane and 164° in the coronal plane. Several measurements were significantly correlated with patient age, including the angle measurements and the distance between the digastric muscles. Aberrant digastric anatomy was common.

CONCLUSIONS

The mylohyoid muscle has multiple radiologically distinct segments with predictable curvatures. An understanding of submental muscular anatomy, along with its variability between patients, may be beneficial to the development of bilateral implantable neurostimulation technology for the treatment of refractory OSA.

LEVEL OF EVIDENCE

N/A Laryngoscope, 134:2970-2975, 2024.

Long-Term Generator Replacement Experience in Hypoglossal Nerve Stimulator Therapy Recipients With CPAP-Intolerant Obstructive Sleep Apnea

OBJECTIVE

In the last decade, hypoglossal nerve stimulation (HNS) has emerged as a therapeutic alternative for patients with obstructive sleep apnea. The original clinical trial cohorts are entering the phase of expected battery depletion (8-12 years). This study aimed to examine the surgical experience with implantable pulse generator (IPG) replacements and the associated long-term therapy outcomes.

STUDY DESIGN

Retrospective analysis of patients from the original clinical trial databases (STAR, German post-market) who were followed in the ongoing ADHERE registry.

SETTING

International multicenter HNS registry.

METHODS

The ADHERE registry and clinical trial databases were cross-referenced to identify the serial numbers of IPGs that were replaced. Data collection included demographics, apnea-hypopnea index (AHI), therapy use, operative times, and adverse events.

RESULTS

Fourteen patients underwent IPG replacement 8.3 ± 1.1 years after their initial implantation. Body mass index was unchanged between the original implant and IPG replacement (29 ± 4 vs 28 ± 2 kg/m2 , p = .50). The mean IPG replacement operative time was shorter than the original implant (63 ± 50 vs 154 ± 58 minutes, p < .002); however, 2 patients required stimulation lead replacement which significantly increased operative time. For patients with available AHI and adherence data, the mean change in AHI from baseline to latest follow-up (8.7 ± 1.1 years after de novo implant) was -50.06%, and the mean therapy use was 7.2 hours/night.

CONCLUSION

IPG replacement surgery was associated with low complications and shorter operative time. For patients with available outcomes data, adherence and efficacy remained stable after 9 years of follow-up.

The impact of frailty on mortality in non-surgical head and neck cancer treatment: Shifting the clinical paradigm

OBJECTIVE

Compare survival of head and neck cancer (HNC) patients treated with surgical or non-surgical management according to frailty, quantify frailty with the Risk Analysis Index (RAI), a validated 14-item instrument.

MATERIALS AND METHODS

Prospective cohort study of newly diagnosed HNC patients (≥18 years) who had frailty assessment from April 13, 2016 to September 30, 2016. Primary outcome was overall survival at 1- and 3-years. Cox proportional hazard models were utilized to examine mortality with predictor variables. Adjusted and unadjusted (Kaplan-Meier) survival curves stratified by either RAI scores or treatment modality were plotted. Kruskal-Wallis and likelihood ratio chi-square tests were used for comparing clinicodemographic variables.

RESULTS

Of 165 patients, 54 (32.7%) were managed non-surgically, 49 (29.7%) were treated with definitive surgery only, and 62 (37.6%) were treated with multimodality (surgery + adjuvant) therapy. Among the full cohort and subgroup analysis of the frail/very frail (RAI ≥ 37), non-surgical patients had worse or similar 3-year survival than those treated with surgery +/- adjuvant therapy. Multivariable Cox proportional hazard models demonstrate that frail patients treated non-surgically experienced worse survival than their counterparts treated with surgery (HR = 2.50, p = 0.015, 95% CI: 1.19, 5.23) or multimodality therapy (HR = 3.91, p < 0.001, 95% CI: 1.94-7.89).

CONCLUSION

Across all levels of frailty, long term survival of HNC patients treated without surgery is either worse than or like those treated with surgery. These findings (1) challenge current practices of steering patients "too frail for surgery" towards non-surgical, "non-invasive" therapy, and (2) suggest equipoise warranting randomized trials to clarify treatment of frail patients.

Subjective and Objective Measures in Assessing Neck Disability and Pain in Head and Neck Cancer

OBJECTIVE/HYPOTHESIS

The intensification of treatment for head and neck cancers (HNCs) has created a cohort of patients living with short- and long-term comorbidities and functional deficits. This study aimed to determine whether there is a relationship between patient-reported outcomes (PROs) and objective measures of neck function in survivors of HNCs.

STUDY DESIGN

Cross-sectional study.

METHODS

Thirty-one subjects (aged 64 ± 8.7 years; 28 males and three females) were recruited and completed the Neck Disability Index (NDI) and a numeric pain scale. At the same visit, subjects were fitted with two portable motion sensors to collect range of motion (ROM) and velocity data. Differences between ROM, velocity, and PRO subgroups were assessed using a one-tailed t test (*P < .05). The Pearson correlation coefficient (r) was calculated between the NDI values and the ROM and velocity values for each motion.

RESULTS

A moderate correlation (r = 0.507) was observed between NDI and neck pain. Patients with no disability according to the NDI had significantly higher ROM and velocity than patients with mild to moderate disability. Velocity in all degrees of freedom (axial rotation, flexion and extension, and lateral bending) was significantly lower for patients who perceived higher levels of neck pain and neck disability.

CONCLUSIONS

This study notes that patients who report neck disability and pain have more limited ROM and velocity following HNC treatment. These data may improve treatment planning and care delivery by facilitating an understanding of the experiences of HNC survivors and the pathophysiology that must be targeted to address their psychosocial and functional deficits.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:2015-2022, 2021.