Literature Review: A roundup of important recent studies

From: ENT Today, September 2010

• Children with OSAS Have Diminished Mucosal Sensation
• A Contemporary Review of Papillomavirus and Oropharynx Cancer
• Fractal Analysis of OSAS Provides Some Information
• Robotic Surgery Offers Advantages for Infratemporal Fossa
• The Application of Posterior Hyoid Space to the Sistrunk Procedure
• Is Comprehensive ASNHL Screening Always Needed?

Children with OSAS Have Diminished Mucosal Sensation

CLINICAL QUESTION

Do children with obstructive sleep apnea syndrome (OSAS) have diminished upper airway sensation compared with controls?

Background: Studies have shown that attenuation of the upper airway mucosal sensation by topical anesthesia increases the tendency of upper airway collapse. These findings suggest that impairment of upper airway mucosal sensation may contribute to upper airway collapse in sleep apnea. Previous studies in adults have demonstrated impaired mucosal sensory function in subjects with OSAS.

Study Design: Prospective case-control study

Setting: Children’s Hospital of Philadelphia

Synopsis: Researchers studied thirteen subjects ages six to 16 with OSAS (apnea-hypopnea index 31±48) and nine normal controls (apnea-hypopnea index 0.4±0.5) who were age-, gender- and body mass index (BMI)-matched. The children were tested while awake using two-point discrimination testing of the mucosa of the anterior tongue and posterior hard palate. Children with OSAS had impaired two-point discrimination of the anterior tongue (p=0.002) and the palate (p<0.0001) when compared to controls. These two areas are supplied by nerves that have been described as part of the afferent innervations of the upper airway negative pressure reflex.

Further study is needed to determine if these findings are due to a congenital abnormality or are secondary to selective nerve damage caused by chronic snoring or mouth breathing. Post-treatment studies are needed to determine if these changes are reversible and to elucidate the pathophysiology of upper airway sensory function in children.

Bottom line: Children with OSAS do have diminished mucosal sensation in the tongue and palate compared to age-, gender- and BMI-matched controls.

Reference: Tapia IE, Bandia P, Traylor J, et al. Upper airway sensory function in children with obstructive sleep apnea syndrome. Sleep. 2010:33(7):968-972.

—Reviewed by Pell Wardrop, MD

 

A Contemporary Review of Papillomavirus and Oropharynx Cancer

CLINICAL QUESTION

What is the evidence for the role of human papillomavirus (HPV) in the etiology of oropharyngeal cancers, methods of viral detection and the resulting clinical implications?

Background: The incidence of head and neck squamous cell carcinoma (HNSCC) has remained stable over the last 15 years, while the incidence of oropharyngeal squamous cell carcinoma (OPSCC), linked both epidemiologically and molecularly to HPV infection, has risen. Fortunately, impressive amounts of clinical and molecular data have been generated in the head and neck cancer literature.

Study design: Contemporary review of literature and conference proceedings

Setting: Department of Otolaryngology-Head and Neck Surgery and Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Mo.

Synopsis: A growing library of evidence details elaborate mechanisms on the molecular level by which HPV may contribute to cellular transformation in squamous mucosal cells. In their review, the authors found that HPV-associated squamous cell carcinomas represent a disease entity distinct from carcinogen-associated squamous cell carcinomas. HPV oncoproteins lead to mucosal cell transformation through well-defined mechanisms, and there are different methods of detecting HPV, each with varying levels of sensitivity and specificity.

Studies demonstrated improved outcomes in HPV-associated carcinoma of the oropharynx only. The cell cycle regulatory protein p16 was shown to be up-regulated by biologically active HPV, serving as a biomarker of improved response to therapy.

Bottom line: Epidemiologic and molecular data document the recognition of a unique subset of HPV-associated OPSCC different from traditional carcinogen-induced HNSCC on the levels of risk factors, tumor development, response to therapy and prognosis. Additionally, the evidence shows that the majority of patients with HPV-associated OPSCC have an improved survival.

Reference: Allen CT, Lewis JS, El-Mofty SK, et al. Human papillomavirus and oropharynx cancer: biology, detection and clinical implications. Laryngoscope. 2010;120(9):1756-1772.

—Reviewed by Sue Pondrom

 

Fractal Analysis of OSAS Provides Some Information

CLINICAL QUESTION

Does fractal quantitative endoscopic evaluation of the upper airway in patients with obstructive sleep apnea syndrome (OSAS) provide objectivity in the interpretation of these studies?

Study Design: Diagnostic test assessment

Setting: Tertiary care private hospital sleep laboratory in Athens, Greece

Background: Fiberoptic nasopharyngolaryngeal endoscopic examination with Müller’s Maneuver (FNPMM) has been used over the years for the evaluation of patients with OSAS. Computer-assisted quantification of the results of this examination is desirable and is limited by the fact that most methods reported have been scale dependent. Slight variations in the position of the scope can affect these results. Fractal geometry creates a fractal dimension that is scale independent.

Synopsis: Researchers used fiberoptic endoscopic nasopharyngolaryngeal examination with and without Müller’s Maneuver to study 25 patients with OSAS and 17 chronic snorers (controls). These examinations were done in awake, non-sedated patients in the erect position. The images recorded in the retropalatal area were analyzed with fractal dimension calculator software. Fractal dimensions (FD) during quiet inspiration (FDI) and during Müller’s maneuver (FDM) were calculated. The degree of area collapsibility (FDAC) was calculated as (FDI – FDM)/FDI.

The FDI was no different in patients with OSAS than in controls. The differences in the FDM and FDAC between OSAS and control patients were significant (p<0.0001). A correlation was found between FDM and apnea-hypopnea index (AHI) (r=-0.481, p<0.01) and between FDAC and AHI (r=0.518, p<0.01).

In differentiating between a positive and negative FDAC, a receiver operating characteristic (ROC) curve was generated and a cutoff point of 0.095 was set. A positive test was defined as FDAC>0.095 and a negative result as FDAC>0.095. The calculated sensitivity was 92 percent, specificity was 82.4 percent and the positive predictive value was 88.5 percent with rather wide confidence intervals for each of these calculations.

Bottom line: Fractal analysis provides some measure of objectivity for the interpretation of endoscopic evaluation of patients with obstructive sleep apnea; however, the real population estimate for sensitivity and specificity needs further study.

Reference: Delides A, Viskos A. Fractal quantitative endoscopic evaluation of the upper airway in patients with obstructive sleep apnea syndrome. Otolaryngol Head Neck Surg. 2010;143(1):85-89.

—Reviewed by Pell Wardrop, MD

 

Robotic Surgery Offers Advantages for Infratemporal Fossa

CLINICAL QUESTION

Does robotic surgery provide better access to the infratemporal fossa (ITF), and is suprahyoid port placement an option?

Background: Recent experimentation with robotic-assisted surgery has shown applications in head and neck surgery and advantages such as excellent three-dimensional microscopic visualization and two-handed, tremor-free operating. These advantages make robotic surgery particularly attractive in areas in which open approaches are technically difficult or functionally morbid, such as ITF.

Study design: Cadaveric studies

Setting: Division of Otolaryngology-Head and Neck Surgery and Department of Neuroradiology, University of Utah Health Sciences Center, Salt Lake City

Synopsis: Using one fixed and three fresh cadaver heads, surgeons performed six complete and two partial bilateral dissections of the ITF using the da Vinci surgical robot. The suprahyoid port side was utilized to place one robotic arm into the vallecula; the second arm and 30-degree camera were placed transorally. Setup times and operative times decreased significantly with increased familiarity with the system. The 30-degree three-dimensional endoscope used during dissections provided excellent visualization into the ITF, and the equipment provided ease of dissection. Computed tomography (CT) imaging after dissections provided evidence of the extent of the dissection, while photographs provided evidence of improved visualization.

Noting that the potential consequences of lateral transcervical port placement are significant, the authors said there is risk of damaging structures. The midline suprahyoid port placement they used “is both novel and highly effective for dissection of wide areas of the skull base bilaterally,” they said, adding that “the suprahyoid port placement is less invasive than a Sistrunk procedure” and has fewer complications.

Bottom line: Use of robotic surgery at the skull base has promising advantages over current open and endoscopic techniques, and the suprahyoid port placement is effective for accessing a wide area of the skull bilaterally.

Reference: McCool RR, Warren FM, Wiggins RH, et al. Robotic surgery of the infratemporal fossa utilizing novel suprahyoid port. Laryngoscope. 2010;120(9):1738-1743.

—Reviewed by Sue Pondrom

 

The Application of Posterior Hyoid Space to the Sistrunk Procedure

CLINICAL QUESTION

If the recurrence of thyroglossal duct cysts (TGDC) occurs as a consequence of incomplete resection, will the application of the posterior hyoid space (PHS) to the Sistrunk procedure minimize the risk of recurrent TGDC?

Background: TGDCs are the most common congenital abnormality in the neck, with surgical extirpation recommended because of the likelihood of recurrent infections and rare cancer. While the Sistrunk procedure is the most efficacious method of surgical extrication, a modified approach used by the authors includes a previously undescribed anatomic area called the PHS.

Study design: A retrospective study

Setting: Department of Surgery, Division of Pediatric Otolaryngology, Children’s Memorial Hospital, Chicago, Ill.

Synopsis: Between April 2003 and August 2008, 60 surgical cases that included age, symptoms, imaging, thyroid status, pathology results and postoperative complications were selected for analysis. All patients underwent a modified Sistrunk procedure and had a postoperative diagnosis of TGDC. The modified approach included skeletonization of the thyroid cartilage to identify the alae and notch of the cartilage. The thyrohyoid membrane was then identified and used as a conduit to locate the posterior aspect of the hyoid bone and to evacuate the PHS anatomic area.

Average patient follow-up was 17 months, with one patient having a recurrence and four patients developing a minor complication. The authors said the anatomy of the PHS has historically been overlooked because when the larynx is harvested at autopsy, the hyoid and epiglottis are not usually included with the specimen.

Bottom line: The authors report a modification of the classic Sistrunk procedure and describe the anatomy of the PHS, along with a low recurrence rate utilizing the modified surgery.

Reference: Maddalozo J, Alderfer J, Modi V. Posterior hyoid space as related to excision of the thyroglossal duct cyst. Laryngoscope. 2010;120(9):1773-1778.

—Reviewed by Sue Pondrom

 

Is Comprehensive ASNHL Screening Always Needed?

CLINICAL QUESTION

What are the costs and diagnostic yield of screening patients presenting with asymmetrical sensorineural hearing loss (ASNHL)?

Background: The magnitude of workup on a patient with ASNHL of an uncertain onset or chronic nature is a problem commonly encountered by otolaryngologists. The typical comprehensive workup includes a number of expensive tests, including a battery of serologic testing and radiographic imaging. Despite the extensive and costly testing available, the etiology of the ASNHL often remains unclear.

Study Design: Retrospective chart review

Setting: Patient charts from New York Eye and Ear Infirmary and University of Minnesota

Synopsis: Of 2,130 patient charts reviewed, 247 met the criteria, which included diagnostic imaging and serum laboratory values. Positive rate was determined for each diagnosis.

To estimate cost-benefits, the authors calculated the average cost for identifying a patient with a positive result. A total of 462 diagnostic tests were performed. The total lab cost was $18,276, compared to the total imaging cost of $246,600.

Of the 247 patients, only six (2.4 percent) were identified with treatable pathology. The image cost for identifying a positive patient was $61,650 based on MRI, compared to the lab cost of $1,142.

Bottom line: Due to the high cost and low yield of MRI among patients presenting with ASNHL, it should be reserved for those presenting with either a high index of suspicion based on clinical symptoms and findings or a serial audiogram showing progression of the ASNHL.

Reference: Wilson YL, Gandolfi MM, Ahn IE, et al. Cost analysis of asymmetric sensorineural hearing loss investigations. Laryngoscope. 2010;120(9):1832-1836.

—Reviewed by Sue Pondrom

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