Therapeutic electrical stimulation of the hypoglossal nerve in obstructive sleep apnea.

BACKGROUND: Hypoglossal nerve stimulation has been demonstrated to relieve upper airway obstruction acutely, but its effect on obstructive sleep apnea is not known. OBJECTIVE: To determine the response in obstructive sleep apnea to electrical stimulation of the hypoglossal nerve. METHODS: Eight patients with obstructive sleep apnea were implanted with a device that stimulated the hypoglossal nerve unilaterally during inspiration. Sleep and breathing patterns were examined at baseline before implantation and after implantation at 1, 3, and 6 months and last follow-up. RESULTS: Unilateral hypoglossal nerve stimulation decreased the severity of obstructive sleep apnea throughout the entire study period. Specifically, stimulation significantly reduced the mean apnea-hypopnea indices in non-rapid eye movement (mean +/- SD episodes per hour, 52.0 +/- 20.4 for baseline nights and 22.6 +/- 12.1 for stimulation nights; P<.001) and rapid eye movement (48.2 +/- 30.5 and 16.6 +/- 17.1, respectively; P<.001) sleep and reduced the severity of oxyhemoglobin desaturations. With improvement in sleep apnea, a trend toward deeper stages of non-rapid eye movement sleep was observed. Moreover, all patients tolerated long-term stimulation at night and did not experience any adverse effects from stimulation. Even after completing the study protocol, the 3 patients who remained free from stimulator malfunction continued to use this device as primary treatment. CONCLUSION: The findings demonstrate the feasibility and therapeutic potential for hypoglossal nerve stimulation in obstructive sleep apnea.

Immediate intraoral adaptation of mandibular advancing appliances of thermoplastic material for the treatment of obstructive sleep apnea.

BACKGROUND: In the treatment of obstructive sleep apnea (OSA), mandibular advancing devices (MAD) are usually individually fabricated on plaster casts of both jaws from polymethyl-methacrylate. The potential disadvantages of these devices are (1) the costs and (2) the time required to construct the device. OBJECTIVE: In this study, the efficacy and feasibility of a cheap MAD consisting of thermoplastic material (SnorBan((R))), which can be directly moulded intraorally, were evaluated. METHODS: In a prospective study, the effect of an MAD consisting of thermoplastic material was investigated in 22 consecutive patients with OSA [respiratory disturbance index (RDI) 32.6 +/- 18.4/h]. Polysomnographic sleep was recorded prior to treatment and after 3 months of treatment with the MAD. RESULTS: Three of the 22 patients who did not tolerate the MAD were excluded from the analysis, whereas 11 patients were classified as responders. In the responder group, the mean RDI decreased from 27.6 +/-7.3 to 7.3 +/- 2.9 (p < 0. 01), correspondingly the sleep quality and the Epworth Sleepiness Scale improved (p < 0.05). Eight patients proved to be non-responders without relevant changes for the measured parameters. CONCLUSIONS: In 50% (11 of 22) of the patients, the MAD improved the OSA to a clinically relevant degree. In contrast to the majority of established MAD, the MAD investigated is cheap and immediately adaptable and thus a feasible strategy to 'screen' the efficacy of this therapeutic principle. Thus the construction of unnecessary MAD is avoided.

Obstructive sleep apnoea in acromegaly: the role of craniofacial changes.

Obstructive sleep apnoea (OSA) is due to craniofacial changes and acromegaly. The question addressed by this study was whether growth hormone (GH) induced craniofacial changes might explain persisting OSA despite endocrine inactivity in acromegaly. Nineteen patients treated for acromegaly were examined cephalometrically for craniofacial changes and polysomnographically for OSA. Twelve patients proved to have OSA with an apnoea/hypopnoea index >15; seven patients showed no evidence of OSA at all. With respect to the endocrinological parameters, there were no differences between the two groups that would explain the presence or absence of OSA. Neither group differed with respect to sex, age, or body mass index. Craniofacial changes were predominantly found in the mandible. The group with OSA proved to have increased vertical, dolichofacial growth compared to those without OSA. Consecutively, in the OSA group the posterior airway space was narrowed, and the hyoid was displaced more caudally. Thus, it seems that craniofacial structures of patients with acromegaly and persisting obstructive sleep apnoea are different from those without obstructive sleep apnoea. Surgical corrections of pertaining acromegaly-induced craniofacial changes should be performed with an awareness of the individual craniofacial condition so as not to enhance obstructive sleep apnoea.

Nasal decongestion with imidazoline derivatives: acoustic rhinometry measurements.

OBJECTIVE: The objective of this single-blind study was to establish whether there are any differences between conventional imidazoline-containing nasal drops with regard to duration of action and decongestion potential. METHODS: Six different substances were each administered to 108 healthy volunteers (nine groups of 12 adults), respectively, in the concentration recommended for adults (and two also in that recommended for infants) over a period of 8 h in comparison with 0.9% NaCl. The volumetric measurement of the nasal lumen was conducted by means of acoustic rhinometry (Rhinoklack). RESULTS: The decongestive effect of all imidazoline preparations set in relatively uniformly, without any appreciable differences. After 20 min all the products exhibited approximately 60% of their maximum decongestive effect, which was achieved after approximately 40 min, having produced an increase in volume of approximately 20%. In contrast, in terms of duration of action, considerable differences between the individual products were to be discerned: indanazoline 0.118%, naphazoline 0.02% and tetryzoline 0.1% had no effect whatsoever after 4 h. Oxymetazoline 0.05% and 0.01%, xylometazoline 0.025% and 0.1%, and tramazoline 0.1264% still had an appreciable effect after 4 h, while after 8 h only oxymetazoline 0.05% and 0.01% still had a relevant decongestive effect. A rebound effect associated with reactive hyperaemia was observed after 8 h in all short-acting products (indanazoline, naphazoline, tetryzoline and tramazoline), which in the case of indanazoline was even associated with a reduction in the nasal lumen. Interestingly, there were no differences between the xylometazoline and oxymetazoline concentrations recommended for adults and those for infants in terms of efficacy. The low-dose concentrations of the preparations for infants appear to be sufficient to produce a satisfactory therapeutic effect.

Sleep fragmentation and daytime vigilance in patients with OSA treated by surgical maxillomandibular advancement compared to CPAP therapy.

Impaired vigilance is a frequent daytime complaint of patients with obstructive sleep apnoea (OSA). To date, continuous positive airway pressure (CPAP) is a well established therapy for OSA. Nevertheless, in patients with certain craniofacial characteristics, maxillomandibular advancement osteotomy (MMO) is a promising surgical treatment. Twenty-four male patients with OSA (pretreatment respiratory disturbance index (RDI) 59.3 SD +/- 24.1 events/h) participated in this investigation. The mean age was 42.7 +/- 10.7 years and the mean body mass index was 26.7 +/- 2.9 kg/m2. According to cephalometric evaluation, all patients had a narrow posterior airway space, more or less due to severe maxillary and mandibular retrognathia. All patients except two were treated first with CPAP for at least 3 months and afterwards by MMO. Two patients only tolerated a CPAP trial for 2 nights. Polysomnographic investigation and daytime vigilance were assessed before therapy, with CPAP therapy and 3 months after surgical treatment. Patients' reports of impaired daytime performance were confirmed by a pretreatment vigilance test using a 90-min, four-choice reaction-time test. The test was repeated with effective CPAP therapy and postoperatively. Daytime vigilance was increased with CPAP and after surgical treatment in a similar manner. Respiratory and polysomnographic patterns clearly improved, both with CPAP and after surgery, and showed significant changes compared to the pretreatment investigation. The RDI decreased significantly, both with CPAP (5.3 +/- 6.0) and postoperatively (5.6 +/- 9.6 events/h). The percentages of non-rapid eye movement Stage 1 (NREM 1) sleep showed a marked decrease (with CPAP 8.2 +/- 3.6% and after MMO 8.2 +/- 4.4% vs. 13.3 +/- 7.4% before treatment), whereas percentages of slow wave sleep increased significantly from 8.0 +/- 6.1% before therapy to 18.2 +/- 12.8 with CPAP and 14.4 +/- 7.3% after MMO. The number of awakenings per hour time in bed (TIB) was significantly reduced after surgery (2.8 +/- 1.3), compared to both preoperative investigation (baseline 4.2 +/- 2.0 and CPAP 3.4 +/- 1.5). Brief arousals per hour TIB were reduced to half with CPAP (19.3 +/- 20.0) and after MMO (19.7 +/- 13.6), compared to baseline (54.3 +/- 20.0). We conclude that the treatment of OSA by MMO in carefully selected cases has positive effects on sleep, respiration and daytime vigilance, which are comparable to CPAP therapy.

[Function and morphology of the temporomandibular joint after mandibular translocation osteotomies with and without positioning plates]. / Kiefergelenkfunktion und -morphologie nach Unterkieferumstellungsosteotomien mit und ohne Positionierungsplatten.

Positioning devices are commonly used to avoid the malpositioning of the proximal segments in bilateral, sagittal split osteotomies and to make sure the preoperative fossa condyle relation is reproduced. The aim of our prospective study, with random selection of 24 patients, was to compare the morphological and functional outcome of the TMJs. The proximal segments in half of the patients had been positioned using devices, in the other half without devices. The segments were fixed by transoral bicortical miniscrew fixation. The evaluation of function is based on pre- and postoperative clinical and electronic axiographic investigations. To study the TMJ morphology, we performed MRI and X-ray investigations preoperatively and 6 months postoperatively. Preoperatively, 12 patients showed slight dysfunction, six patients moderate, and six patients severe dysfunction. Postoperatively, no patient was symptomless. Slight dysfunction was presented in 15 cases, moderate dysfunction in five and severe dysfunction in four cases. Evaluating the axiographic investigations preoperatively, 22 patients showed no mobility disturbances of the TMJ. Two patients showed severe mobility disturbances. Postoperatively, a significant increase in TMJ mobility disturbances could be seen. The MRI investigations of both groups showed both worsening and improvement in the disk positions. No significant differences could be determined between the two groups, however. Regarding the X-ray investigation, three patients from the group with positioning devices showed dislocated condyles; in the group without positioning devices four cases of condyle dislocation were seen. All dislocations were transversal except for one case in the group without positioning devices. Positioning devices do not seem to improve the functional and morphological outcome of the TMJ after BSSO.

Four-year-old girl with Goldenhar-sequence and severe obstructive sleep apnea, symptoms, diagnosis and therapy.

Recently sleep related breathing disorders in children have received considerable attention. Unfortunately, cardiorespiratory polygraphy is expensive and time-consuming, and up until now today only a few pediatric hospitals have complete facilities for all-night cardiorespiratory polygraphy. Nevertheless, the prevalence of sleep related breathing disorders in children is higher than has previously been thought. To show the importance of proper diagnosis of sleep related breathing disorders, we report a case of a 4-year-old girl with severe obstructive sleep apnea caused by Goldenhar-sequence (facio-auriculo-vertebral dysplasia). Despite some treatment efforts to correct the aplastic right mandible, the symptoms of obstructive sleep apnea were not immediately recognized and remained untreated. Untreated obstructive sleep apnea led to growth and mental retardation. After polygraphic confirmation of obstructive sleep apnea and appropriate interdisciplinary treatment, the 4-year-old girl made rapid advances in growth and mental development.

[Obstructive sleep apnea in the child: an interdisciplinary treatment concept with special reference to craniofacial changes]. / Obstruktive schlafbezogene Atmungsstörungen beim Kind: Ein interdisziplinäres Behandlungskonzept unter besonderer Berücksichtigung kraniofazialer Veränderungen.

Diagnosis and therapy of obstructive sleep-related breathing disturbances SRBD in adults may not be applied without hesitation to children. SRBD in newborn and infants are often due to craniofacial disturbances (Pierre Robin syndrome, Goldenhars syndrome etc.), obesity is of minor importance. More than 30 infants with SRBD and craniofacial changes have been diagnosed and successfully treated over a 2-year period. Conservative therapy starts immediately after birth. The first step in newborn with Pierre Robin syndrome, for instance, is prone position for protrusion of tongue and mandible and mandibular growth stimulation. Intermediate nightly nasopharyngeal tubes are an alternative to nCPAP-/BiPAP treatment. Conventional orthopaedic/orthodontic treatment should not be neglected, even if it takes years to become effective. Surgical therapies are able to support, sometimes to replace or at least to shorten conservative methods. In rare cases when prone position in combination with palatal plates in cases of Robin syndrome, for instance, are not fully effective, mandibular extension is indicated. Aplasia or defects demand adequate surgical reconstruction, even if this does not necessarily mean abolishment of SRBD. In contrast to adults adenotonsillectomy is highly effective in infants and does not only reduce SRBD, but also improves nasal breathing and thus positively influences facial growth. A relatively new method is gradual mandibular distraction osteogenesis according to Ilizarov, which also enhances soft tissue growth. Maxillary and mandibular advancement osteotomies should not be considered before the termination of facial growth. Thanks to this refined treatment concept we were able to avoid tracheotomies in children during the past few years.

[TMJ-function and -morphology after mandibular translocation-osteotomies with and without positioning plates]. / Kiefergelenkfunktion und -morphologie nach Unterkieferumstellungsosteotomien mit und ohne Positionierungsplatten.

Positioning devices are commonly used to avoid the malpositioning of the proximal segments in bilateral, sagittal split osteotomies and to make sure the preoperative fossa condyle relation is reproduced. The aim of our prospective study, with random selection of 24 patients, was to compare the morphological and functional outcome of the TMJs. The proximal segments in half of the patients had been positioned using devices, in the other half without devices. The segments were fixed by transoral bicortical miniscrew fixation. The evaluation of function is based on pre- and postoperative clinical and electronic axiographic investigations. To study the TMJ morphology, we performed MRI and X-ray investigations preoperatively and 6 months postoperatively. Preoperatively, 12 patients showed slight dysfunction, six patients moderate, and six patients severe dysfunction. Postoperatively, no patient was symptomless. Slight dysfunction was presented in 15 cases, moderate dysfunction in five and severe dysfunction in four cases. Evaluating the axiographic investigations preoperatively, 22 patients showed no mobility disturbances of the TMJ. Two patients showed severe mobility disturbances. Postoperatively, a significant increase in TMJ mobility disturbances could be seen. The MRI investigations of both groups showed both worsening and improvement in the disk positions. No significant differences could be determined between the two groups, however. Regarding the X-ray investigation, three patients from the group with positioning devices showed dislocated condyles; in the group without positioning devices four cases of condyle dislocation were seen. All dislocations were transversal except for one case in the group without positioning devices. Positioning devices do not seem to improve the functional and morphological outcome of the TMJ after BSSO.

The influence of maxillary osteotomy on nasal airway patency and geometry.

Maxillary surgical repositioning affects nasal airway size. This study recorded nasal airway changes by acoustic rhinometry in patients with maxillary surgical repositioning after Le Fort I osteotomies. These changes were compared to the amount of skeletal movement by means of preoperative and 6-week postoperative lateral cephalography. Vertical linear movement of the posterior maxilla showed a very close relationship to volume changes in the posterior nasal segment. Anterior nasal volume changes can not be considered as a pure function of the direction and amount of skeletal movement. The greatest amount of cranial displacement tolerated without impaired nasal patency in this study was 7 mm.

Surgical maxillofacial treatment of obstructive sleep apnea.

Obstructive sleep apnea is the most common sleep-related breathing disorder, with a surprisingly high prevalence. The treatment of choice is nasal continuous positive airway pressure (CPAP) ventilation during sleep, which has to be applied throughout the patient's whole life. Because of various underlying pathomechanisms in patients with certain craniofacial disorders--narrow posterior airway space and maxillary-mandibular deficiency--surgical therapy by craniofacial osteotomies seems possible. A series of 38 consecutive patients were treated by 10-mm maxillomandibular advancement by retromolar sagittal split osteotomy and Le Fort I osteotomy, respectively. Obstructive sleep apnea syndrome was improved considerably in all patients; there was no significant difference compared to the results under nasal CPAP. In 37 of 38 patients, the postoperative apnea-hypopnea index was reduced clearly to under 10 per hour, oxygen saturation rose, and sleep quality improved. This was achieved by maxillomandibular advancement of 10 mm without secondary refinements in all but 2 patients. In one patient, the apnea-hypopnea index could only be reduced to 20 per hour, probably because of insufficient maxillary advancement. These results indicate that successful surgical treatment is possible in a high percentage of selected patients with certain craniofacial characteristics. In addition to cardiorespiratory polysomnography, there should be routine cephalometric evaluation of all patients. Maxillomandibular advancement should be offered as an alternative therapy to all patients with maxillary and/or mandibular deficiency or dolichofacial type in combination with narrow posterior airway space.

Long-term follow-up after surgical treatment of obstructive sleep apnoea by maxillomandibular advancement.

Obstructive sleep apnoea (OSA) is a common disorder with potentially serious consequences. If maxillary and mandibular deficiency, often in combination with a narrow posterior airway space is present, therapy of OSA by maxillomandibular osteotomy is possible. However, long-term follow-up of patients undergoing these procedures is lacking. We present the results of 15 OSA patients (1 female and 14 males), who underwent maxillomandibular advancement surgery with a follow-up of at least 2 yrs. Polysomnography was performed before surgery, after 6-12 weeks, and 1 and 2 yrs postoperatively. Mean apnoea/hypopnoea index (AHI) decreased from 51.4 events.h-1 before therapy to 5.0 events.h-1 6 weeks postoperatively, and was 8.5 events.h-1 after 2 yrs. Oxygen saturation significantly increased following surgery. After 2 yrs, the AHI was < 10 events.h-1 in 12 out of 15 subjects. No significant changes were found comparing the 6-12 weeks versus the 2 year follow-up data. The significant increase in stage 3/4 non-rapid eye movement (NREM) sleep and decrease in stage 1 NREM sleep, indicative of the restoration of normal physiological sleep structure, persisted in 14 of the 15 subjects 2 yrs postoperatively. Three patients, however, did not show satisfactory improvement 2 yrs postoperatively; two showed obstructive and one central respiratory events. This study demonstrates that maxillomandibular advancement is successful in a high percentage of patients carefully selected by cephalometric and polysomnographic investigation. Postoperative success has proved to be stable over a period of 2 yrs. Further preoperative evaluation seems necessary in patients with predominantly mixed or central apnoeas.

[Mechanical/prosthetic protrusion of the mandible: effects on the pharynx]. / Mechanisch-/prothetische Unterkieferprotrusion: Auswirkungen auf den Pharynx.

Pharyngeal Effects: The protrusion of the mandible by prosthetic appliances ("Esmarch-prosthesis") may be a simple therapy for obstructive sleep apnea, but is effective only in rare cases. Aim of this study was the cephalometric investigation of pharyngeal changes by mechanic-/prosthetic mandibular protrusion in respect of the amount of protrusion. Cephalometric investigation was performed in 46 patients before and after mandibular protrusion, subdivided into 3 groups with protrusion of less than 7 mm, 7 to 10 mm, and more than 10 mm. A significant pharyngeal enlargement was found in all patients, but there was no correlation between the amount of protrusion and the amount of pharyngeal enlargement. Mandibular protrusion of more than 10 mm did not necessarily lead to more pharyngeal enlargement. A reliable prognosis of pharyngeal enlargement in respect of the amount of mandibular protrusion is not possible by cephalometric evaluation, even less a reliable prognosis of treatment success in respect of obstructive sleep apnea.

Mandibular setback for surgical correction of mandibular hyperplasia--does it provoke sleep-related breathing disorders?

The question has arisen as to whether mandibular setback may possibly cause sleep-related breathing disorders (SRBD). To evaluate the possible effects of mandibular setback on posterior airway space (PAS), 16 consecutive patients were examined prospectively. All patients underwent surgical mandibular setback using bilateral sagittal split osteotomy. Polysomnographic evaluation for SRBD was performed according to the Marburg graded diagnostic protocol before and after surgery. Cephalometric analysis was performed preoperatively, and 1 week, 3 months, and 1 year postoperatively, with particular attention to pharyngeal changes. PAS decreased considerably in all patients. Nevertheless, the preoperative PAS was enlarged in all patients with mandibular hyperplasia compared to normal subjects. Despite the pharyngeal narrowing, there was no evidence of postoperative SRBD in any of these patients. SRBD as a consequence of mandibular setback may be rare; nevertheless, the pharyngeal airway does decrease.

[nCPAP therapy and maxillary and mandibular osteotomy compared: attention during the day in obstructive sleep apnea]. / NCPAP-Therapie und Ober--und Unterkiefer-Osteotomie im Vergleich: Vigilanz am Tage bei obstruktiver Schlafapnoe.

11 patients with obstructive sleep apnea (OSA) and maxillary and mandibular characteristics participated. All patients received nCPAP therapy for at least 3 months. The surgical treatment principle consists of 10 mm maxillary and mandibulary advancement. Cardiorespiratory polysomnography (cPSG) control was assessed 3 months after surgical treatment. The daytime vigilance was investigated using a 90-min 4-choice reaction-time test. Patients reports of excessive daytime sleepiness (EDS) were confirmed by pre-treatment vigilance testing. Accordingly, daytime vigilance, respiratory and polysomnography patterns were improved with nCPAP and surgical treatment in a likewise manner. The tolerance to monotonous situations increased distinctly with nCPAP as well as after osteotomy. Surgical treatment of OSA in carefully selected cases has positive effects on sleep and daytime vigilance. There were no significant differences in the cPSG nor in vigilance tests with regard to nCPAP therapy.

[Surgical reposition and fixation of mandibular condyle fractures via intraoral approach]. / Zur operativen Reposition und Fixation von Unterkiefergelenkfortsatzfrakturen von enoral.

In a case series 54 patients with 61 subcondylar fractures had been treated by surgical repositioning and miniplate-fixation by an intraoral approach. Functional results with special regard to the function of the temporomandibular joint TMJ were registered not earlier than 1 year postoperatively and compared to a case series of 48 patients with 63 conservatively treated subcondylar fractures. Axiographic or pantographic investigation proved higher incidence of TMJ-disorders as it was the case for the common clinical functional examination. TMJ-function was worse in the conservatively treated cases especially in dislocated fractures. Therefore dislocated fractures especially with luxation of the TMJ should be surgically treated. Surgical repositioning and fixation by an intraoral approach is difficult and allows only limited access and view of the fracture, but avoids complications by scaring or facial nerve damage and seems to be sufficient for adequate repositioning. Minor dislocations showed no influence on TMJ-function. Of course surgical repair of disrupted TMJ-ligaments is not possible by an intraoral approach-disrupted TMJ-ligaments in luxated joints seem to be of major importance for the later TMJ-function.

[Differential therapeutic aspects in treatment of obstructive sleep apnea syndrome]. / Differentialtherapeutische Aspekte zur Behandlung des obstruktiven Schlafapnoesyndroms.

We report the case of a 43-year-old man who suffered from obstructive sleep apnea with excessive daytime sleepiness and nocturnal sweating. His initial apnea index of 60/h improved under treatment with an Esmarch device. Apneas were totally suppressed by nCPAP application with a pressure of only 4 mb, but the patient rejected nCPAP therapy. After two years with the Esmarch device he reported increasing temporomandibular joint pain and Esmarch therapy had to be stopped. A cephalometric evaluation showed good prognosis for maxillomandibular advancement osteotomy, which was performed and which suppressed the apneas completely over a period of more than one year. Indication, surgical technique, and risks are discussed.

[Surgical treatment of obstructive sleep apnea by osteotomy of the facial bones (results of 1 year)]. / Zur chirurgischen Behandlung der obstruktiven Schlafapnoe durch Gesichtsskelettosteotomien (Jahresergebnisse).

Surgical treatment of obstructive sleep apnea with abolition of obstructive apneas and hypopneas is possible by maxillomandibular advancement as our own results in 24 patients show. Maxilla and mandible must be advanced at least about 10 mm to secure success. Indication for maxillomandibular advancement should be restricted to patients with certain craniofacial disorders, which are of retrognathic dolichofacial type combined with pharyngeal narrowing. Before considering surgical treatment other possible contributing factors as for instance obesity should be eliminated, the more as nCPAP-therapy constitutes an effective conservative method. Despite our unchanged success rate after 1 year further polysomnographic follow-up control is essential to see what happens 5, 10 or 20 years after maxillomandibular advancement.

Acoustic rhinometry: a new diagnostic procedure--experimental and clinical experience.

The diagnostic value of transnasal acoustic reflection measurements (Rhinoklack) was investigated in an experimental and clinical study. Within the range of nasal and epipharyngeal dimensions, in vitro and in vivo measurements showed satisfactory reproducibility. A simple maneuver helps to identify the transition from the rigid nasal cavity to the movable epipharynx. The location and the amount of nasal obstruction can be verified and traced back to their morphologic correlative. The effect of decongestion on nasal volume was measured for normal mucosa (41% enlargement) and mucosa altered by scar formation after septoplasty and turbinoplasty (21% enlargement). After maxillomandibulary advancement of 10 mm for obstructive sleep apnea, the EV index representing epipharyngeal volume (EV) showed an average increase of 6 cm3.