Literature Review: A Roundup of Important Recent Studies

Transnasal Balloon Catheter Dilation of Eustachian Tube Relieves Ear Pressure

Is there a way to relieve refractory middle ear pressure symptoms from Eustachian tube dysfunction other than through myringotomy and tubes?

Background: About 1 percent of adults in the general population have Eustachian tube dysfunction, and the percentage of these patients in otolaryngology practices is much higher. For patients with nasal symptoms, the standard treatment typically includes nasal steroid spray, antihistamines and decongestants. If there are no concomitant nasal symptoms, a myringotomy with or without a tube is often performed. The recent advent of nasal sinus balloon catheters raises the question of the feasibility of transnasal balloon catheter dilation of the Eustachian tube.

Study design: Prospective, non-controlled.

Setting: Academic practice.

Synopsis: Seventy adult patients underwent 100 Eustachian tube dilations (40 unilateral, 30 bilateral) for symptoms of chronic ear pain, pressure, fullness and otitic barotrauma. Patients were evaluated for temporomandibular joint disease, childhood ear disease and cochlear hydrops, and were excluded if positive. Sixty-three percent of patients had general anesthesia for concomitant procedures, and 37 percent had local anesthesia in the office setting. Overall, 71 percent of 100 ears showed notable improvement or reduction in symptoms, with average follow-up of 30.6 weeks.

Bottom line: Transnasal balloon catheter dilation of the Eustachian tube is in the early stages of development. Several issues, including those surrounding objective outcome measures, the best combination of dilation pressure, the size of the balloon diameter, duration of dilation and more specific indications, need better definition. However, this technique seems feasible and holds promise in properly selected patients.

Citation: Catalano PJ, Jonnalagadda S, Yu VM. Balloon catheter dilatation of Eustachian tube: a preliminary study. Otol Neurotol. 2012;33:1549-1552.

—Reviewed by Larry Lundy, MD

Fat Graft Myringoplasty Highly Successful in Certain Tympanic Membrane Perforations

What are the characteristics of a chronic tympanic membrane perforation that favor an in-office fat graft myringoplasty?

Background: Options for closure of chronic tympanic membrane perforations include cauterization with trichloroacetic acid, paper patches, gelfoam plugs, fat grafts and formal tympanoplasty. The selection of technique and successful outcome depends on multiple factors.

Study design: Prospective cohort study.

Setting: Tertiary referral center.

Synopsis: Eighty-two adults with unilateral perforations present for six months and longer were enrolled if they also met specific criteria: absence of ossicular or mastoid pathology, nonmarginal location of perforation, normal middle ear mucosa, no evidence of cholesteatoma, no discharge within the previous three months and no major Eustachian tube dysfunction. The edges of the perforation were freshened, and an oversized piece of earlobe fat was placed through the perforation in an hourglass fashion. The overall success rate was 85 percent, but the rate of success significantly decreased when the perforation was greater than 30 percent of the pars tensa.

Bottom line: Dry stable chronic tympanic membrane perforations of 30 percent or less of the pars tensa have a high rate of successful closure with fat graft myringoplasty under local anesthesia in the office setting.

Citation: Konstantinidis I, Malliari H, Tsakiropoulou E, Constantinidis J. Fat myringoplasty outcome analysis with otoendoscopy: who is the suitable patient? Otol Neurotol. 2013;34:95-99.

—Reviewed by Larry Lundy, MD

Molecular Testing May Improve Differentiated Thyroid Cancer Diagnoses

Can molecular testing for gene point mutations and rearrangements be used to diagnose differentiated thyroid cancer more accurately?

Background: Thyroid cancer progresses through a series of genetic and epigenetic changes. Study authors looked for manuscripts featuring BRAF and RAS gene point mutation, RET/PTC chromosomal rearrangements, PAX8/PPARγ chimeric fusion rearrangement and multigene expression (mRNA) tests. BRAF, RET/PTC and PAX8/PPARγ have a high positive predictive value; gene expression microarrays have a high negative predictive value.

Study design: Review of 286 English-language manuscripts with clinical correlates from 2006 to 2012.

Setting: Ovid Medline manuscripts.

Synopsis: The most useful molecular markers available at a commercial level are BRAF and RAS mutations; mRNA testing is also available commercially. The most common clinically useful markers are BRAF and RAS point mutations. BRAF has >99 percent specificity and is rarely found in benign neoplasma. This test has limitations for undetermined lesion diagnosis because many thyroid cancers are negative for the BRAF mutation. Testing for a panel of mutations (BRAF, RAS, RET/PTC) resulted in a 36 percent gain in sensitivity (44 percent to 80 percent). In addition, the authors found that many BRAF+ tumors do not behave aggressively, and BRAF+ PTC tumors generally have a higher rate of central node compartment metastasis. RET/PTC tumors are not commonly aggressive. Negative predictive values from mRNA testing were found for undetermined follicular lesions (95 percent), follicular neoplasm (94 percent) and suspicious cytologic features (85 percent). Microarray testing may also eliminate the need for unnecessary diagnostic lobectomy in 60 percent to 90 percent of cases. The authors found a 10-fold reduction in surgery rates for cytologically indeterminate nodules (74 percent to 7.6 percent) for gene expression classifier benign results. However, performance characteristics of negative predictive value testing require further study.

Bottom line: Molecular alteration testing used in clinical practice may reduce the number of unnecessary thyroid procedures and completion thyroidectomies, and may lead to more individualized operative and post-operative care.

Citation: Witt RL, Ferris RL, Pribitkin EA, Sherman SI, Steward DL, Nikiforov YE. Diagnosis and management of differentiated thyroid cancer using molecular biology. Laryngoscope. 2013;123:1059-1064.

—Reviewed by Amy Eckner

Polysomnography Widely Used in Pediatrics, but Not Up to Practice Guidelines

How frequently do pediatric otolaryngologists use polysomnograms (PSG) in their practices for children with sleep-disordered breathing (SDB)?

Background: The American Academy of Pediatrics (AAP) published 2002 guidelines for management of snoring in children, with PSG as the gold standard of diagnosis for obstructive sleep apnea (OSA) and adenotonsillectomy as the first-line treatment. A 2004 survey of American Society of Pediatric Otolaryngology (ASPO) members showed that PSG was rarely requested.

Study design: A 20-question, five-minute cross-sectional survey was sent to ASPO members in June 2011.

Setting: Internet-based.

Synopsis: The response rate for the survey was 39 percent (135/345), with three members opting out. The majority of respondents “sometimes” requested a PSG for children with suspected SDB (65 percent) and did not use home sleep testing (81 percent). The primary reason for requesting a PSG was inconsistent history and physical examination (58 percent). Comorbidities (obesity, 38 percent; Down syndrome, 56 percent; younger than 3 years, 22 percent) affected PSG requests. The median and mode for observation following an outpatient tonsillectomy were each three hours. PSG was less likely to be requested post-operatively for children with obesity or Down syndrome. Wait time for PSG was a significant factor in frequency of request: There was a 10.4 percent greater chance physicians would order a PSG for ever week of wait time for the PSG. At least 69 percent of respondents “sometimes” request a PSG; however, respondents were less likely to request a pre-operative PSG for children who are obese, have Down syndrome or are younger than 3 years. Access to a dedicated pediatric sleep lab has increased from 67 percent to 86 percent, and the current average wait for a sleep study is 5.7 weeks. Survey limitations include a relatively low response rate, variation in access to sleep laboratories and differences in ASPO member practices.

Bottom line: Although requests for PSG prior to tonsillectomy have increased, they are still not compliant with AAP or American Academy of Sleep Medicine guidelines.

Citation: Friedman NR, Perkins JN, McNair B, Mitchell RB. Current practice patterns for sleep-disordered breathing in children. Laryngoscope. 2013;123:1055-1058.

—Reviewed by Amy Eckner

Length of Intubation, Number of Sedation Doses Affect Subglottic Stenosis Risk in Children

Do the length of endotracheal intubation and other risk factors increase the incidence of subglottic stenosis (SGS) in children?

Background: As the use of mechanical ventilation in children has increased, so, too, has the incidence of SGS. However, risk factors for the development of laryngeal lesion after intubation remain unclear. To the study authors’ knowledge, this is the first prospective research protocol evaluating the incidence of post-intubation SGS in children by carrying out flexible fiberoptic laryngoscopy (FFL) in all study patients. Previous studies have reported findings on neonates, and previous incidence in literature is variable.

Study design: Prospective research protocol.

Setting: Intensive care unit, Hospital de Clínicas de Porto Alegre, Rio Grande do Sul, Brazil.

Synopsis: The study included 142 children, from birth to younger than 5 years, who were admitted and required endotracheal intubation for more than 24 hours. Participants underwent FFL within the first eight hours after extubation. Examinations were performed at the pediatric ICU (PICU) bedside, without sedation, and patients were positioned across the bed with no neck hyperextention. All PICU intubation procedures, except those that were urgent, followed the protocol of fast intubation sequence, use of midazolam, fentanyl and rocuronium. Patients were monitored daily for repositioning of endotracheal tube, number of reintubations and the need to maintain or increase sedation. The evaluation was based on parameters that included respiratory response, physical movement, blood pressure, heart rate and muscle tone, but without an objective scale. Eighty-four patients had normal examinations or mild lesions, while 58 had moderate or severe lesions. The incidence of SGS in the sample was 11.3 percent (16 patients); of those, two had grade I SGS, five had grade II SGS, six had grade III SGS and three had grade IV SGS. For every additional five days of intubation, the risk of SGS increased by 50.3 percent; for each additional sedation dose per day, the risk increased by 12 percent. A limitation of this study is the lack of application of existing validated scales for patient agitation.

Bottom line: The study found a higher overall incidence of SGS compared with most previous studies. The length of intubation and additional sedative doses were found to be critical factors for SGS development.

Citation: Manica D, Schweiger C, Cauduro Maróstica PJ, Kuhl G, Antonacci Carvalho PR. Association between length of intubation and subglottic stenosis in children. Laryngoscope. 2013;123:1049-1054.

—Reviewed by Amy Eckner

Little Difference Between Tetracaine and Lidocaine for Nasal Endoscopy

Is there a difference in comfort levels and other negative side effects between use of atomized 2 percent tetracaine and 4 percent lidocaine for nasal endoscopy patients?

Background: Nasal endoscopy is generally performed in an outpatient setting, with patients given a topical anesthetic for improved comfort. However, there is no consensus on the most effective topical anesthetic for patient comfort. This study examined atomized 2 percent tetracaine and 4 percent lidocaine. According to the study authors, to date there have been no prospective, randomized trials that specifically evaluate patient discomfort, comparing tetracaine and lidocaine, during nasal endoscopy.

Study design: Prospective, randomized, double-blind study

Setting: Department of Otolaryngology, MedStar Washington Hospital Center, Washington, D.C.

Synopsis: Ninety-nine study participants enrolled between July 2011 and May 2012 were randomized to receive either tetracaine or lidocaine. Both physicians and patients were blinded to the anesthetic administered. Patients received two atomized sprays of oxymetazoline and then three sprays of the topical anesthetic; before proceeding, the investigator waited three minutes. The senior author performed all endoscopies for consistency. The mean age of participants was 58.0±16.2 years. Patients were then asked to complete a nine-question survey evaluating comfort level and adverse symptoms using a 10-point analog scale. Participants older than age 58.01±16.20 were more likely to have less overall pain and discomfort and to experience an unpleasant taste. Patients older than age 59.96±16.76 were less likely to suffer from globus sensation and dysphagia in the tetracaine group. The highest score was for unpleasant taste in both anesthetics. The authors found no significant differences between the lidocaine and tetracaine groups. No gender differences were found. Limitations of the study included inherent subjectivity, possible differences in discomfort if a longer waiting time was used, the lack of a placebo arm and a question of whether having a physician with less experience performing the endoscopies would change the results.

Bottom line: There were similar effects using 2 percent tetracaine and 4 percent lidocaine on patients undergoing transnasal fiberoptic endoscopy, although tetracaine may be a better choice for older patients.

Citation: Gaviola GC, Chen V, Chia SH. A prospective, randomized, double-blind study comparing the efficacy of topical anesthetics in nasal endoscopy. Laryngoscope. 2013;123:852-858.

—Reviewed by Amy Eckner

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