Tongue anatomy and physiology, the scientific basis for a novel targeted neurostimulation system designed for the treatment of obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea (OSA) is a chronic condition that affects millions adults. The effective standard treatment is positive airway pressure (PAP). However, approximately half of the patients that are prescribed PAP are unable or unwilling to comply with this therapy. Untreated OSA ultimately leads to very serious comorbidities. An alternative therapy for this patient population, therefore, is desirable. Hypoglossal nerve (HGN) stimulation is under investigation by multiple groups as a possible alternative therapy for OSA. OBJECTIVE: To understand the underlying mechanisms of actions related to HGN stimulation, and the implication of this knowledge for specifying and designing a neurostimulation system for the treatment of OSA. RESULTS: Loss of lingual and pharyngeal tone within a narrow airway is the primary mechanism for OSA. Posterior and anterior tongues are different in their anatomy and physiology. Muscle fibers in the posterior tongue are predominantly fatigue resistant that are responsible for the long sustained tonic activities required for maintaining the tongue's position and preventing its mass from falling into the retroglossal airway. The human tongue is a muscular hydrostat and hence would benefit from a sophisticated HGN stimulation system that is capable of achieving a concerted spatio-temporal interplay of multiple lingual muscles, including retrusors. CONCLUSION: Targeted neurostimulation of the proximal HGN presents as a viable system approach that is far more versatile and physiologic and quite different than prior systems.

Regional variations in chronic rhinosinusitis, 2003-2006.

OBJECTIVES: 1. Characterize patient visits for chronic rhinosinusitis on the basis of age, gender, race, diagnostic services, and medication use. 2. Evaluate regional differences in patient visits for chronic rhinosinusitis. STUDY DESIGN: Analysis of cross-sectional survey data from two national databases of ambulatory medical encounters. SETTING: Not applicable. SUBJECTS AND METHODS: Four years (2003-2006) of data from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey were analyzed. Visits involving chronic rhinosinusitis were identified by using reported diagnostic codes from the International Classification of Diseases, Ninth Revision. They were weighted to provide national estimates of care. Data were analyzed with the Pearson chi(2) test using the SPSS 16.2 Complex Samples Module, taking into account the complex survey design and multiple time periods. RESULTS: A total of 4617 patient visits for chronic rhinosinusitis were identified, accounting for 1.95 percent of all visits. With the application of weights to this sample, these visits represent 91.2 million national visits. A significantly higher proportion of visits in the South involved African Americans (Pearson chi(2) = 69.5, F = 6.7, df = 2.8, 2118, P < 0.01). Significantly fewer diagnostic services were provided or ordered in the Northeast (Pearson chi(2) = 64.8, F = 4.0, df = 4.3, 3247, P < 0.01). Providers in the Northeast were also significantly less likely to order or renew more than three medications at the visit (Pearson chi(2) = 54.0, F = 3.1, df = 2.6, 1930, P < 0.05). No regional differences were seen for age, gender, or setting type. CONCLUSION: Significant regional variations exist for chronic rhinosinusitis in patient demographics, diagnosis, and management. Continuing research is needed to refine physician awareness, evaluation, and treatment of this disorder.

Gender differences in obstructive sleep apnea and treatment implications.

Obstructive sleep apnea (OSA) is a common cause of daytime sleepiness for millions of Americans. It is also a disease associated with an increased likelihood of hypertension, cardiovascular disease, stroke, daytime sleepiness, motor vehicle accidents, and diminished quality of life. A number of population-based studies have shown that OSA is more common in men than in women and this discrepancy is often evident in the clinical setting. There are a number of pathophysiological differences to suggest why men are more prone to the disease than women. Although the exact mechanisms are unknown, differences in obesity, upper airway anatomy, breathing control, hormones, and aging are all thought to play a role. The purpose of this review was to examine the literature on gender differences in OSA and to analyze whether or not these differences in pathogenic mechanisms affect diagnosis or treatment.

Sleep medicine for surgeons.

Sleep medicine is an important component of current head and neck surgery practices. Furthermore, obstructive sleep apnea is an anatomic disease of the upper respiratory tract, a region of anatomy best known to head and neck surgeons. If head and neck surgeons choose to participate in the surgical treatment of sleep apnea, they must develop expertise in the evaluation and home sleep testing aspects of sleep apnea. Because positive airway pressure remains the front line treatment, they must also develop expertise in the prescription of positive airway pressure therapy.

Waist circumference and sleep disordered breathing.

OBJECTIVES/HYPOTHESIS: To explore how the different metrics of obesity, specifically body mass index (BMI), Mallampati, neck circumference, waist circumference, and waist-hip ratio, correlate with metrics of sleep disordered breathing (SDB), specifically the apnea/hypopnea index (AHI), and which is/are the most likely to predict and correlate with SDB. STUDY DESIGN AND METHODS: Four hundred fourteen patients presenting to the University of California San Diego Head and Neck Surgery Clinic for SDB had a sleep evaluation including a history and physical examination assessing the markers of obesity and a sleep test. Data comparing AHI with BMI, neck circumference, waist circumference, waist-hip ratio, and Mallampati were analyzed by means, standard deviations, and Pearson's correlations. RESULTS: The mean AHI for males was 34, and the mean AHI for females was 24. The mean age was 48 for both sexes. The mean waist circumference for males was 104 cm (41 inches) and for females 99 cm (39 inches). In males and females, waist measurement was most strongly correlated with SDB (males: r = 0.366, P = .00; females: r = 0.445, P = .00). The mean neck circumference for males and females was 43 cm (17 inches) and 38 cm (15 inches) (males: r = 0.358, P = .00; females: r = 0.38, P = .00). The mean waist-hip ratio for males and females was 0.94 and 0.87 (males: r = 0.359, P = .00; females: r = 0.254, P = .03). The mean BMI for males and females was 31 kg/m2 (males: r = 0.325, P = .00; females: r = 0.40, P = .00), and the mean Mallampati for males and females was 2.84 and 2.92 (males: r = 0.176, P = .012; females: r = 0.149, P = .16). A linear regression demonstrated that waist and neck circumference were better correlates of SDB than BMI. CONCLUSION: Obesity correlates with SDB severity. Waist circumference is a better measure than BMI or neck circumference to predict SDB. Men and women are anthropometrically different. Even with an AHI of 5 or more, only half of SDB patients in this study were clinically obese. An abnormal waist circumference for men and women is 102 cm (40 inches) or more.

Tissue preparation for MOHS' frozen sections: a comparison of three techniques.

Accurate, efficient frozen section analysis is important for tumor control. A few studies address the technical issues. More are needed, especially as new technologies become available. The objective of this study is to compare the efficiency of three techniques of flattening tissue for microscopically oriented histologic surgery (MOHS): conventional frozen sectioning, Cryocup, and CryoHist. Conventional chuck/heat sink-frozen section preparation were compared with Cryocup and CryoHist to determine the most efficient technique to examine 100% of the surgical margin of 4-cm diameter, full thickness, fresh autopsy cylinders of anterior abdominal skin, which were marked on their deep and peripheral margins. The specimens were frozen sectioned at 5 microm until all the marking dye was gone from the deep surface, and 95% of the perimeter epidermis could be seen. The conventional chuck required an average of 304 micrometers to clear the deep margin and four fifths did not contain 95% of the epidermal margin. The Cryocup required an average of 284 microm to examine the deep margin and 95% of the epidermal margin. The CryoHist required an average of 104 microm to examine the deep margin and 95% of the epidermal border. The new techniques improve the efficiency and presumably the accuracy of tumor margin analysis.

Lingual fat at autopsy.

OBJECTIVES/HYPOTHESIS: Obesity as measured by body mass index (BMI) has been shown to correlate with incidence and severity of sleep disordered breathing (SDB), but the actual mechanism underlying this relationship has not been defined. Pharyngeal obstruction from posterior displacement of a large, fat laden tongue is one mechanism that may explain this link. The objective of this study is to characterize the fat content within the tongue and then to determine whether tongue weight and percent of fat correlate with BMI and other metrics of obesity. STUDY DESIGN: This is a cross-sectional anatomic study performed at autopsy in 121 consecutive medical examiner cases. METHODS: Tongues were harvested, weighed, and sectioned. A standardized photograph was taken of each tongue in the midsagittal plane. The image was imported into ImageJ (NIH) and then digitally analyzed to estimate fat distribution and percent within the tongue. The measurements were divided into age and sex subsets and then examined for correlation with height, weight, BMI, organ weight, and abdominal subcutaneous fat thickness. RESULTS: This study includes data from 88 males, 27 females, and 6 children. The average tongue weight for males was 99 g, range 71 to 143 g; for females, 79 g, range 51 to 135 g; and for children, (mean age 4 yr) 38 g, range 15 to 81 g. Tongue weight correlated with BMI (r = 0.6, P < .0001). Percent of fat in the posterior tongue averaged 30 +/- 12% and correlated with BMI (r = 0.5, P < .0001) for both men and women. Percent of fat in the anterior tongue averaged 10 +/- 5% and correlated with BMI for males (P < .001). Anterior tongue fat percent did not correlate with BMI in females. CONCLUSION: Increase in tongue weight and percentage of fat, and therefore tongue volume, may explain why patients with weight gain have higher rates of SDB. Tongue weight, fat, and volume may also correlate with and explain Mallampati grades.

A two-dimensional model of anatomic relationships during laryngoscopy.

BACKGROUND: The view obtained during direct laryngoscopy is only seen by a single anesthesiologist. The inability of instructors to observe the view poses problems for teaching the technique. The anatomic interactions affecting laryngoscopy are largely internal, hampering efforts to understand why some patients are unexpectedly difficult to intubate. In response, we have constructed a full scale, adjustable, two-dimensional model showing the head and neck in the sagittal plane. In this article, we validate the mannequin and test how various conditions or changes in equipment affect the laryngoscopic view. METHODS: Model parameters were compared with literature values. Glottic exposure was evaluated over a range of jaw lengths and interincisor gaps for Macintosh 3, Miller 2, and Macintosh 4 blades. RESULTS: Thirty segmental airway distances and 10 angles were within 1 standard deviation from published values. Spine and jaw mobilities approximated normal range of motion. Glottic exposure decreased steeply for mouth openings below a threshold. A larger mouth opening was required to obtain a view when the mandible was short. None of the blades exposed the glottis when mouth opening was narrow, 2.4 cm. The Macintosh 4 blade was closest to success, within 7 mm of viewing the posterior cords. CONCLUSIONS: The model reflects an average 16-yr-old male patient in size, proportion, and mobility. It can be used to explicate how anatomic relationships affect laryngoscopy. An objective assessment is necessary to determine the model's utility for teaching and as a tool for researching the mechanisms responsible for laryngoscopic difficulty.

Home sleep testing in the diagnosis and treatment of sleep disordered breathing.

Sleep-disordered breathing is a growing public health concern and an integral part of head and neck surgery. Multichannel home sleep testing is a cost-effective, patient-friendly, scientifically valid technique of evaluating patients who present with symptoms of sleep-disordered breathing, typically snoring or daytime sleepiness. Home sleep tests can be dispensed from the physician's office. They have a 95% successful recording rate. Scoring can be autoscore or manual score. There are several protocols that can be followed based on diagnostic outcomes.

Intranasal zinc and anosmia: the zinc-induced anosmia syndrome.

OBJECTIVE: Commercial preparations of intranasal zinc gluconate gel are marketed as a remedy for the common cold. However, intranasal zinc has been reported as a cause of anosmia in humans and animals. Seventeen patients presenting with anosmia after the use of intranasal zinc gluconate are described. METHODS: The authors conducted a retrospective case series of patients presenting to a nasal dysfunction clinic and conducted complete history and physical examination on all patients, including nasal endoscopy. All patients underwent detailed odor threshold and identification testing. RESULTS: Threshold and identification testing revealed impaired olfaction in all patients. Inflammatory and traumatic causes of anosmia were excluded based on history, physical examination, and imaging. All patients diagnosed with zinc-induced anosmia or hyposmia reported sniffing deeply when applying the gel. This was followed by an immediate sensation of burning lasting minutes to hours. Loss of sense of smell was then perceived within 48 hours. Seven of 17 patients never developed symptoms of an upper respiratory infection. CONCLUSIONS: The zinc-induced anosmia syndrome, characterized by squirt, sniff, burn, and anosmia, occurs after the exposure of olfactory epithelium to zinc cation. It can be distinguished from postviral anosmia based on history.

Searching the literature using medical subject headings versus text word with PubMed.

OBJECTIVE/HYPOTHESIS: This study was conducted to investigate the performance of two search strategies in the retrieval of information from the National Library of Medicine (NLM) on otolaryngology-head and neck surgery related conditions and diagnoses using PubMed. METHODS: Two search strategies-one based on the use of Medical Subject Headings (MeSH) and the second based on text word searching-were compared. RESULTS: The MeSH search provided a more efficient search than the text word search. CONCLUSIONS: Head and neck surgeons can most efficiently search the NLM using PubMed as a search engine by initiating the search with MeSH terms. Once a key article is identified, the searcher should use the "Related Articles" feature.

Olfactory dysfunction: a sequela of pediatric blunt head trauma.

OBJECTIVE: To evaluate olfactory function in children with blunt head trauma. METHODS: Eligible subjects were consecutive children presenting at San Diego Children's Hospital Emergency Department or Trauma Service with blunt head trauma. Thirty-seven head injured children mean age 10.11+/-2.74 were evaluated; 36 healthy age and gender matched community children, mean age 10.08+/-2.99, served as controls. The medical record was reviewed for clinical measures related to head injury (HI). All children underwent olfactory assessment with the San Diego Children's Odor Identification Test (SDOIT). Olfactory event-related potentials were recorded on a subset of head injured and control children. RESULTS: Three of 37 head injured children had olfactory dysfunction. The head injured hyposmics had signs of more severe head injury represented by lower Glasgow Coma Scores (GCS), 10.33+/-5.51, when compared to their normosmic counterparts with mean GCS of 14.06+/-2.82. When stratifying the head injured children by clinical measures, lower Glasgow Coma Score, and abnormalities on head CT scan were associated with poorer olfactory performance. CONCLUSION: Children with blunt head injury may suffer post-traumatic olfactory impairment. More severe head injuries are more likely to produce olfactory deficits. In cases of significant head injury, cranial nerve I evaluation is imperative.

The anatomic basis for the acquisition of speech and obstructive sleep apnea: evidence from cephalometric analysis supports The Great Leap Forward hypothesis.

BACKGROUND AND PURPOSE: We previously postulated how evolutionary changes in man's upper respiratory tract to facilitate speech, a phenomenon Jared Diamond calls The Great Leap Forward, have predisposed man to obstructive sleep apnea (OSA) [Diamond J. The Third Chimpanzee: the evolution and future of the human animal. New York: HarperCollins Publishers; 1992. p. 21, 23, 32-54, 54-6; Davidson TM. The Great Leap Forward: the anatomic evolution of obstructive sleep apnea. Sleep Medicine 2003;4:185-94]. We grouped these anatomic changes into four categories: klinorynchy, laryngeal descent, craniobase angulation and supralaryngeal vocal tract (SVT) ratio of SVT(H):SVT(V). This study was designed to investigate the relationship between cephalometric measures corresponding to these anatomic changes and OSA. PATIENTS AND METHODS: One hundred and twenty-three male subjects presenting with symptoms of OSA underwent unattended multi-channel home sleep studies. We obtained cephalometric measurements from standard lateral cephalograms. Pearson correlation coefficients were calculated between cephalometrics and apnea-hypopnea index (AHI), age, and body mass index (BMI). RESULTS: Our results showed significant correlation between AHI and klinorynchy, laryngeal descent, and craniobase angulation. CONCLUSIONS: Overall, our data supports the theory that evolutionary anatomic changes to facilitate speech correlate with OSA severity. The cumulative changes in each cephalometric category trended in the directions hypothesized and support the Great Leap theory of OSA evolution.

Scar management: prevention and treatment strategies.

PURPOSE OF REVIEW: Aberrant wound healing results in unsightly scar, hypertrophic scar, and keloid formation, causing functional and cosmetic deformities, discomfort, psychological stress, and patient dissatisfaction. Scar prevention and management, both surgical and nonsurgical, continue to be important issues for the otolaryngologist. RECENT FINDINGS: Both animal and human models continue to point to the integral role of transforming growth factor-beta in aberrant healing. Multiple extracts have promising results as therapies for scarring and are widely marketed but need to be further investigated. Scar prevention advancements include refinements in surgical technique, nutritional supplementation, and optimal wound care. Steroid injections continue to play a major role in the regression of scars and keloids. Dermatography assists in the minimization of scar appearance. Dermatography, laser therapies, intralesional 5-fluorouracil, and adjuvant radiotherapy are emerging therapies. Topical vitamin E utility is revisited. New surgical scar revision techniques include modified excision techniques and skin grafting. SUMMARY: Despite optimal efforts to avoid scar formation, aberrant wound healing may occur. The use of topical agents and intralesional steroid injections can minimize early scar formation. Strategies for prevention and management of keloids and hypertrophic scars continue to develop, as the basic science mechanisms underlying aberrant wound healing are elucidated.

Reducing motor-vehicle collisions, costs, and fatalities by treating obstructive sleep apnea syndrome.

STUDY OBJECTIVES: Drivers suffering from obstructive sleep apnea syndrome (OSAS) have an increased risk for being involved in motor-vehicle collisions. This study estimates, for the first time, the annual OSAS-related collisions, costs, and fatalities in the United States and performs a cost-benefit analysis of treating drivers suffering from OSAS with continuous positive airway pressure (CPAP). DESIGN: The MEDLINE-PubMed database (1980 to 2003) was searched for information on OSAS. A meta-analysis was performed of studies investigating the relationship between collisions and OSAS. Data from the National Safety Council were used to estimate OSAS-related collisions, costs, and fatalities and their reduction with treatment. Next, the annual cost of treating OSAS with CPAP was calculated. Finally, multiple 1-way sensitivity analyses were performed. SETTING: N/A. PATIENTS OR PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: More than 800,000 drivers were involved in OSAS-related motor-vehicle collisions in the year 2000. These collisions cost 15.9 billion dollars and 1,400 lives in the year 2000. In the United States, treating all drivers suffering from OSAS with CPAP would cost 3.18 billion dollars, save 11.1 billion dollars in collision costs, and save 980 lives annually. CONCLUSION: Annually, a small but significant portion of motor-vehicle collisions, costs, and deaths are related to OSAS. With CPAP treatment, most of these collisions, costs, and deaths can be prevented. Treatment of OSAS benefits both the patient and the public.

The Great Leap Forward: the anatomic basis for the acquisition of speech and obstructive sleep apnea.

Obstructive sleep apnea is an anatomic illness caused by evolutionary changes in the human upper respiratory tract. These changes include shortening of the maxillary, ethmoid, palatal and mandibular bones, acute oral cavity-skull base angulation, pharyngeal collapse with anterior migration of the foramen magnum, posterior migration of the tongue into the pharynx, descent of the larynx and shortening of the soft palate with loss of the epiglottic-soft palate lock-up. While it is commonly believed that some of these changes had positive selection pressures for bipedalism, binocular vision and locomotion, development of voice, speech and language ultimately became a substantial contributing factor. Here it is shown that these changes are the anatomic basis of obstructive sleep apnea.

Nightly variability of sleep-disordered breathing measured over 3 nights.

OBJECTIVE: To examine the nightly variability of sleep-disordered breathing (SDB) as measured by the apnea-hypopnea index (AHI). STUDY DESIGN AND SETTING: Retrospective comparison of 3 sequential nights of testing performed in the home in 1091 patients who were referred for diagnostic testing of SDB. RESULTS: The Pearson and Intraclass correlation coefficients ranged between 0.88 and 0.90 for each pair of nights. Based on night 1, approximately 90% of patients were classified consistently with "AHI-high" (the highest AHI measured across the 3 nights) using an AHI threshold of 5. However, 10% were misclassified on night 1 relative to the highest AHI level. CONCLUSION AND SIGNIFICANCE: These findings suggest that (1) 1 night of diagnostic testing for SDB is not sufficient to diagnosis SDB in approximately 1 of every 10 cases, and (2) there is little, if any, significant nightly change in SDB in the home environment. EBM RATING: D.

Clinical evaluation of postoperative sinonasal surgical patients.

Rhinosinusitis is a very common upper respiratory illness. Functional endoscopic sinus surgery has been successfully utilized in the surgical treatment of medically refractory rhinosinusitis. The endoscopic approach has also been extended to various skull base lesion and sinonasal neoplasms. This paper provides a brief overview of the clinical aspect of evaluating sinonasal surgical patients. Judicious use of nasal endoscopy and importance of CT imaging of the sinuses are discussed. Emphasis is placed on establishing communication between the sinus surgeon and radiologist to facilitate evaluation of the sinonasal surgical patients. liming and specific types of imaging studies before any revision sinus surgery are discussed. Major complications associated with endoscopic sinus surgery are reviewed.