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Literature Review: A Roundup of Important Recent Studies

Observation, T&A Common Interventions for Obstructive Sleep Events in Infants

What types of nonsurgical and surgical interventions are commonly used for obstructive sleep events in infants?

Background: Previous studies suggest that infants are particularly vulnerable to obstructive sleep events and may have an increased predilection for more severe obstructive sleep apnea (OSA). Both nonsurgical and surgical interventions are used to treat pediatric OSA. Although polysomnography (PSG) is the standard for OSA diagnosis, there is still debate regarding diagnostic criteria and severity grading in infants.

Study design: Retrospective medical record review of patients aged three to 24 months at the time of diagnosis of OSA by PSG.

Setting: Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center.

Synopsis: A total of 295 patients met inclusion criteria (196 males, 99 females). Medical records were analyzed for the duration of their care in the otolaryngology/pulmonary clinics after diagnosis, including interventions/outcomes occurring after age 24 months. In general, as OSA severity increased, there was a concomitant increase in the percentage of patients with abnormal arousal index and oxygen desaturation. Gastroesophageal reflux disease (GERD) was the most common comorbidity, followed by recurrent otitis media/Eustachian tube dysfunction. Congenital syndromes were diagnosed in 38 patients, with Down syndrome the most common. A total of 364 interventions were performed, with some infants undergoing more than one. The most frequent: for mild OSA, observation, adenotonsillectomy (T&A) and adenoidectomy; for moderate OSA, T&A adenoidectomy and observation; for severe OSA, T&A, adenoidectomy and supplemental O2. Data showed that, subjectively, T&A was the most effective intervention, while supplemental O2 was the least. Limitations included the fact that only 105 interventions could be assessed for objective efficacy and that the relatively low cure rate is likely a poor representation of true efficacy due to infrequent post-intervention PSGs.

Bottom line: Observation was the most common nonsurgical intervention and the most common intervention in patients younger than 12 months, while T&A was the most common surgical and overall intervention and had the greatest subjective efficacy.

Citation: Robison JG, Wilson C, Otteson TD, Chakravorty SS, Mehta DK. Analysis of outcomes in treatment of obstructive sleep apnea in infants. Laryngoscope. 2013;123:2306-2314.

—Reviewed by Amy Eckner

CT, MRI Not Useful for Evaluation of ED Patients with Dizziness

Are computed tomography (CT) and magnetic resonance imaging (MRI) useful and cost-effective in the evaluation of patients with dizziness in the emergency department (ED)?

Background: Dizziness is the chief complaint in about 4 percent of patients presenting to the ED. Because the differential diagnosis for dizziness is extensive, many physicians, including otolaryngologists, use imaging as a first-line modality to rule out more serious causes.

Study design: Retrospective chart review of patients with a specific health maintenance insurance plan presenting with dizziness and vertigo between January 2008 and January 2011.

Setting: Henry Ford Health System, Detroit.

Synopsis: A total of 1,681 charts were reviewed to examine the presenting complaints, physical exam, laboratory test and radiological tests. Patients with a history of stroke, brain tumor, recent neurosurgery or a predisposing neurological disorder were excluded. Of 1,028 patients who received CT, 810 were specifically for dizziness or vertigo; of those, only 50 had abnormal findings, with six that were clinically significant. Of the 90 patients who received MRI, 16 had abnormal findings, with 11 that were clinically significant. Patients with CT or MRI abnormal findings had either neurological or ophthalmological complaints as well. For every increase of 10 years in age, the chance of having a CT scan went up 1.41 times. A single CT scan was $1,220; total charges for 810 cases were $988,200. MRI charges were $2,696 per study; total charges for the 90 cases were $242,640. Limitations included possible selection bias from use of a specific HMO and possible underreporting of patients with abnormal radiological findings due to use of ICD-9 codes.

Bottom line: CT and MRI of the head in all patients presenting to the ED is not helpful in identifying the cause of dizziness and is not cost effective.

Citation: Ahsan SF, Syamal MN, Yaremchuk K, Peterson E, Seidman M. The costs and utility of imaging in evaluating dizzy patients in the emergency room. Laryngoscope. 2013;123:2250-2253.

—Reviewed by Amy Eckner

Combined Use of EEA and TORS Effective for Skull Base Surgery

Are current robotic approaches to skull base surgery effective?

Background: Skull base surgery can be difficult and complex, given the presence of nearby vital structures. Endoscopic endonasal approaches (EEAs) are a surgical alternative for treating benign and malignant sinonasal tract and skull base lesions that can provide exposure to neurovascular structures. Robotic-assisted surgery (TORS) can also facilitate complex surgeries in difficult-to-access areas of the upper aerodigestive tract.

Study design: Fresh cadaveric specimen dissection.

Setting: Robotic Skills Laboratory, The Ohio State University Wexner Medical Center, Columbus.

Synopsis: A fresh cadaveric specimen was dissected at the center’s Robotic Skills Laboratory. The laboratory environment was designed to be similar to that of a standard operating room. To facilitate the transnasal-transoral approach, researchers performed a posterior septectomy, enabling the transnasal introduction of an 8-mm 0° robotic camera. A transoral corridor provided access to the hard palate. For the transpalatal approach, a U-shaped mucosal incision was performed 5 mm medial to the maxillary dentition of the hard palate. Adjunctive transcervical ports allowed robotic instrument introduction directed cranially toward the clivus. A 1.5-cm incision allowed the manual introduction of the ports. Various combinations of camera corridors and EndoWrist instrument were reviewed. The transoral camera (30°) and instruments provided good control of the posterior and lateral nasopharynx; however, they did not provide adequate access over the roof of the nasopharynx or posterior choana. The transnasal camera (0°) and trans-

oral instruments provided excellent visualization, but instrumentation was cumbersome. Neither EEA nor TORS solved the problem of drilling the skull base.

Bottom line: In combined use, EEA and TORS provide excellent exposure of the posterior skull base, nasopharynx and infratemporal fossa.

Citation: Ozer E, Durmus K, Carrau RL, et al. Applications of transoral, transcervical, transnasal, and transpalatal corridors for robotic surgery of the skull base. Laryngoscope. 2013;123:2176-2179.

—Reviewed by Amy Eckner

Cartilaginous Tissue Regeneration with Bioengineered Trachea

Is a bioengineered trachea effective in the rapid regeneration of the trachea in pediatric patients?

Background: Many times, surgical treatment including tracheal or laryngotracheal reconstruction is required for tracheal or subglottic stenosis management to avoid suffocation or dyspnea. For tracheal reconstruction, Teramachi and Nakamura and colleagues developed a tracheal prosthesis with polypropylene mesh and rings as a frame and collagen sponge as a scaffold. Because the frame does not expand, however, only adult cases have benefited.

Study design: Prospective controlled trial in an animal model.

Setting: Fukushima Medical University, Fukushima City, Japan.

Synopsis: A bioengineered trachea composed of autologous chondrocytes was developed, and its effect on cartilaginous regeneration was evaluated by surgical implantation into tracheal defects in 12-week-old male Japanese white rabbits. A tracheal prosthesis without chondrocytes was implanted in a control group. At two weeks after implantation, cartilaginous tissue formation was not clearly observed in the bioengineered group with H&E staining, but Alcian blue staining revealed regenerated cartilaginous tissue at the defect; in the control group, no cartilaginous tissue was observed in the tracheal prosthesis or at the edge of the tracheal cartilage. At eight weeks, regenerated cartilaginous tissue was observed in the bioengineered trachea, and the tracheal cartilage defect had been repaired into a ring-shaped form as a whole; in the control group, no regenerated cartilaginous tissue was observed in the tracheal prosthesis. At 14 weeks, more regenerated cartilaginous tissue was apparent in the bioengineered trachea, and the defect repair was maintained in the ring-shaped form as a whole.

Bottom line: Cartilaginous tissue regeneration using a bioengineered trachea with autologous chondrocytes derived from costal cartilage is the first step toward developing an artificial trachea with regenerated cartilage.

Citation: Nomoto M, Nomoto Y, Tada Y, et al. Bioengineered trachea using autologous chondrocytes for regeneration of tracheal cartilage in a rabbit model. Laryngoscope. 2013;123:2195-2201.

—Reviewed by Amy Eckner