OSA Upper Airways Surgery: A Targeted Approach

Potential of computational models in personalized treatment of obstructive sleep apnea: a patient-specific partial 3D finite element study

The upper airway experiences mechanical loads during breathing. Obstructive sleep apnea is a very common sleep disorder, in which the normal function of the airway is compromised, enabling its collapse. Its treatment remains unsatisfactory with variable efficacy in the case of many surgeries. Finite element models of the upper airway to simulate the effects of various anatomic and physiologic manipulations on its mechanics could be helpful in predicting surgical success. Partial 3D finite element models based on patient-specific CT-scans were undertaken in a pilot study of 5 OSA patients. Upper airway soft tissues including the soft palate, hard palate, tongue, and pharyngeal wall were segmented around the midsagittal plane up to a width of 2.5 cm in the lateral direction. Simulations of surgical interventions such as Uvulopalatopharyngoplasty (UPPP), maxillo-mandibular advancement (MMA), palatal implants, and tongue implants have been performed. Our results showed that maxillo-mandibular advancement (MMA) surgery of 1 cm improved the critical closing pressure by at least 212.2%. Following MMA, the best improvement was seen via uvulopalatopharyngoplasty (UPPP), with an improvement of at least 19.12%. Palatal and tongue implants also offered a certain degree of improvement. Further, we observed possible interacting mechanisms that suggested simultaneous implementation of UPPP and tongue stiffening; and palatal and tongue stiffening could be beneficial. Our results suggest that computational modeling is a useful tool for analyzing the influence of anatomic and physiological manipulations on upper airway mechanics. The goal of personalized treatment in the case of OSA could be achieved with the use of computational modeling.

A Critical Analysis of Pharyngeal Patterns of Collapse in Obstructive Sleep Apnea: Beyond the Endoscopic Classification Systems

(1) Background: Drug-Induced Sleep Endoscopy (DISE) enables the three-dimensional and dynamic visualization of the upper airway (UA) during sleep, which is useful in selecting the best treatment option for obstructive sleep apnea (OSA) patients, particularly for surgical procedures. Despite international consensus statements or position papers, a universally accepted DISE methodology and classification system remain a controversial open question. (2) Methods: A review of the English scientific literature on DISE related to endoscopic classification systems and surgical outcome predictors (3) Results: Of the 105 articles, 47 were included in the analysis based on their content's relevance to the searched keywords. (4) Conclusions: A final report and scoring classification system is not universally accepted; the most internationally applied endoscopic classification system during DISE does not cover all patterns of events that occur simultaneously during the endoscopic examination, highlighting that several configurations of collapse and obstruction at different UA levels could be observed during DISE, which should be described in detail if DISE has to be considered in the decision-making process for the UA surgical treatment in OSA patients and if DISE has to have a role as a predictive factor for surgical outcomes analysis.

The Reliability of Three-Dimensional Landmark-Based Craniomaxillofacial and Airway Cephalometric Analysis

Cephalometric analysis is a standard diagnostic tool in orthodontics and craniofacial surgery. Today, as conventional 2D cephalometry is limited and susceptible to analysis bias, a more reliable and user-friendly three-dimensional system that includes hard tissue, soft tissue, and airways is demanded in clinical practice. We launched our study to develop such a system based on CT data and landmarks. This study aims to determine whether the data labeled through our process is highly qualified and whether the soft tissue and airway data derived from CT scans are reliable. We enrolled 15 patients (seven males, eight females, 26.47 ± 3.44 years old) diagnosed with either non-syndromic dento-maxillofacial deformities or OSDB in this study to evaluate the intra- and inter-examiner reliability of our system. A total of 126 landmarks were adopted and divided into five sets by region: 28 cranial points, 25 mandibular points, 20 teeth points, 48 soft tissue points, and 6 airway points. All the landmarks were labeled by two experienced clinical practitioners, either of whom had labeled all the data twice at least one month apart. Furthermore, 78 parameters of three sets were calculated in this study: 42 skeletal parameters (23 angular and 19 linear), 27 soft tissue parameters (9 angular and 18 linear), and 9 upper airway parameters (2 linear, 4 areal, and 3 voluminal). Intraclass correlation coefficient (ICC) was used to evaluate the inter-examiner and intra-examiner reliability of landmark coordinate values and measurement parameters. The overwhelming majority of the landmarks showed excellent intra- and inter-examiner reliability. For skeletal parameters, angular parameters indicated better reliability, while linear parameters performed better for soft tissue parameters. The intra- and inter-examiner ICCs of airway parameters referred to excellent reliability. In summary, the data labeled through our process are qualified, and the soft tissue and airway data derived from CT scans are reliable. Landmarks that are not commonly used in clinical practice may require additional attention while labeling as they are prone to poor reliability. Measurement parameters with values close to 0 tend to have low reliability. We believe this three-dimensional cephalometric system would reach clinical application.

Treatment of sleep disordered breathing relapse after surgery

This narrative review provides a general overview of the management of relapses after surgery for the treatment of sleep disordered breathing. This clinical scenario represents a challenging field, but fortunately several therapeutic options are included in sleep surgeons’ armamentarium. Each therapeutic modality is described in detail in a dedicated section.

Palatopharyngeal Arch Staging System (PASS): Consensus about Oropharyngeal Evaluation

Intraoral examinations are essential in the evaluation of the upper airway in patients with obstructive sleep apnea (OSA). The morphology of the anatomic structures of the soft palate, the tonsillar fossae, and the palatoglossus and palatopharyngeal muscles is an important determinant of the size and collapsibility of the velum and oropharynx. The Palatopharyngeal Arch Staging System (PASS) is a systematic way to explore the oropharynx and report anatomic variations in the visible part of the palatopharyngeal muscle. In this prospective study, 30 sleep surgeons evaluated the reliability of the PASS using a selection of 23 videos of oropharyngeal examinations of healthy patients. The corresponding score on the PASS scale was graded for each examination. For internal structure and internal agreement, the Cronbach and Krippendorff alpha values were 0.96 and 0.46, which corresponded to a nearly perfect interrelationship and a moderate agreement, respectively. These findings suggest that the PASS is a valuable tool for evaluating the position of the palatopharyngeus muscle during oropharyngeal examinations and may be useful for creating a common language for sleep surgeons when evaluating the palatopharyngeal muscle.

Role of functional and anatomic study in sleep endoscopy for treatment of OSA

Objective

To describe a clear and intuitive way to analyse the anatomical meaning of images observed in Drug-induced Sleep Endoscopy (DISE) to fully understand the obstructive dynamics and therefore opt for a tailor-made pharyngeal surgical technique.

Methods

From January 2016 to December 2020, 298 patients who underwent DISE were selected according to inclusion criteria.

Results

The case series consisted of 204 males and 94 females with a mean age of 56 years. Body mass index ranged from 19 kg/m² to 34 kg/m² with a median of 26.5 kg/m². Median Apnoea-Hypopnea Index (AHI) was 27 (range 5-62.3). The authors also observed four palate pharyngeal phenotypic patterns of collapse and clarify the morphology and role of the main muscles involved in upper airway collapse.

Conclusions

DISE is fundamental to determine the collapse site in patients affected by obstructive sleep apnoea syndrome. The velopharyngeal region is the most common site of obstruction and lateral pharyngeal wall collapse is the major determining factor. DISE can lead to a deeper understanding of the obstructive dynamic patterns and a more precise identification of the muscle bundles responsible for upper airway collapse.

Head-Of-Bed Elevation (HOBE) for Improving Positional Obstructive Sleep Apnea (POSA): An Experimental Study

Purpose: Evaluate the effectiveness of the head-of-bed elevation position (HOBE) with a 30° elevation of the head and trunk, in improving obstruction of the upper airways in obstructive sleep apnea (OSA) patients. A prospective trial simultaneously performing drug-induced sleep endoscopy (DISE) and polysomnography (PSG) tests was performed. Methods: Forty-five patients were included in the prospective study protocol. All patients enrolled in the study and underwent the following evaluations: (1) a drug-induced sleep endoscopy, with an evaluation of obstructions and collapse of the upper airways at 0° and in a HOBE position, with head and trunk elevation of 30°; (2) an overnight PSG assessment in the hospital with head and trunk elevation from 0° to 30° during the night; (3) a questionnaire to evaluate the feedback of patients to sleeping with head-of-bed elevation. Results: Velum (V) and oropharynx lateral wall (O) collapses were reduced in the 30° up position. There were no statistical differences that emerged in the obstruction of the tongue base and epiglottis between the 0° position and the 30° up position (p > 0.05). The average AHI score changed from 23.8 ± 13.3 (0° supine position) to 17.7 ± 12.4 (HOBE position), with a statistical difference (p = 0.03); the same statistical difference emerged in the percentage of apneas that decreased from 55 ± 28.1 to 44 ± 25.8 (p = 0.05). Conclusions: By adopting the HOBE position with 30° elevation of the head and trunk, it is possible to obtain a reduction of upper airways collapses and an improvement of apnea/hypopnea events and nightly respiratory outcomes.

Obstructive Sleep Apnea Syndrome: From Symptoms to Treatment

Obstructive sleep apnea (OSA) syndrome is a respiratory sleep disorder characterized by partial or complete recurrent episodes of upper airway collapse that occur during the night. The OSA manifests with a reduction (hypopnea) or complete cessation (apnea) of airflow in the upper airways, associated with breathing effort. OSA is a frequent and often underestimated pathology affecting between 2 and 5% of the middle-aged population. Typical nocturnal symptoms are the persistent snoring and awakenings with dyspnea sensation. On the other hand, diurnal symptoms could be sleepiness, headaches, asthenia, neurological disorders, and impaired personal relationships. Surgery of the velo-pharyngeal region had a huge evolution going from ablative techniques (UP3 and LAUP) to remodeling techniques of the pharyngeal lateral walls.

Assessment of the Effectiveness of Obstructive Sleep Apnea Treatment Using Optical Coherence Tomography to Evaluate Retinal Findings

Retinal findings may change in patients with obstructive sleep apnea syndrome (OSAS). The present study aims to evaluate several retinal findings, such as macula layer thickness, the peripapillary retinal nerve fiber layer, and the optic nerve head in patients with OSAS, using optical coherence tomography (OCT); it also aims to monitor the result of several types of treatment of OSAS with OCT. A prospective comparative study was designed. Patients were recruited at a Sleep Unit of a University Hospital and underwent comprehensive ophthalmological examinations. Following exclusion criteria, fifty-two patients with OSAS were finally included. Patients were examined by OCT twice: once before treatment, and again after six months of treatment. In mild–moderate patients, where retinal swelling had been demonstrated, retinal thicknesses decreased [fovea (p = 0.026), as did inner ring macula (p = 0.007), outer ring macula (p = 0.015), and macular volume (p = 0.015)]. In severe patients, where retinal atrophy had been observed, retinal thickness increased [fovea (p < 0.001)]. No statistically significant differences in efficacy between treatments were demonstrated. In conclusion, OCT can evaluate the retina in patients with OSAS and help to monitor results after treatment. In severe OSAS, retinal thickness increased six months after treatment.

Barbed reposition pharyngoplasty (BRP) in obstructive sleep apnea treatment: State of the art

PURPOSE

In this paper, we perform a systematic review that discusses the state of the art and evolution on the barbed reposition pharyngoplasty (BRP) in the velo-pharyngeal surgery. Clinical evidence and published outcomes of this surgical technique are reported and discussed.

MATERIALS AND METHODS

We performed a systematic review of the current literature through the analysis of the last 10 years of literature on barbed palate surgery. Study design, number of patients enrolled, inclusion criteria, pre- and posttreatment outcomes (AHI, ODI), surgical success rate, follow-up time and complication has been collected and reported.

RESULTS

15 studies for a total of 1531 patients, out of which 1061 underwent barbed reposition pharyngoplasty. Five trials were uncontrolled prospective studies (215 patients, 14% of total), nine were retrospective studies (1266 patients, 82,6% of total), and one randomized prospective clinical trial (RCT) (50 patients, 3,32% of total). All analyzed studies reported good outcomes after BRP surgery. Average preoperative values of AHI and ODI reduced in all studies considered with a significative statistical difference between preoperative and postoperative values (p < 0.05 in all cases). The postoperative surgical success rate ranged between 65.4 and 93% of cases. There were no significant intra-operative or post-operative complications in all studies considered in this systematic review.

CONCLUSIONS

Barbed reposition pharyngoplasty has proven to be an easy to learn, quick, safe and effective new palatopharyngeal procedure, that can be used in a single level surgery or as a part of multilevel procedures.

Hypoglossal Nerve Stimulation Therapy

Hypoglossal nerve stimulation (HNS) has been shown to be a safe alternative in the treatment of moderate-to-severe obstructive sleep apnea (OSA). A recent meta-analysis of 12 studies by Costantino et al. indicated the surgical success rates at 55-75%, a reduction of the apnea hypopnea index (AHI) of 18 events/h, and a reduction of the Epworth Sleepiness Scale (ESS) of 2.9-5.3. After animal studies in the 1970s, the first trial on humans to decrease upper airway resistance by transcutaneous electrical stimulation of the genioglossus was reported in 1989. A separate stimulation of protruding and retracting muscles was realized in 1995 by fine-wire electrodes that were placed into the tongue transoral. Over the next years, several companies developed implantable devices for hypoglossal stimulation in OSA. Initially, devices were developed that used unilateral stimulation of the hypoglossal nerve. In 2014, a device for unilateral respiratory frequency-controlled hypoglossal stimulation finally received FDA approval after a successful phase III trial. In recent years, a device for bilateral breath rate-independent stimulation of the hypoglossal nerve has been added to these approaches as a new development. Accordingly, hypoglossal nerve stimulation, on the one hand, is now an established tool for patients with OSA when standard treatments are not satisfactory. Beyond that, hypoglossal stimulation is undergoing a continuous and impressive development like hardly any other field of surgical therapy for OSA.