- Bilateral Cochlear Implants Improve Spatial Acuity
- SSCD Treated with Surgical Plugging
- Vocal Fold Paresis Following Neonatal Cardiac Surgery
- Management of Temporal Bone Defects after Oncologic Resection
- Pattern of Active HPV Expression Correlates to Disease Course
- Safety of Antimicrobial Photodynamic Therapy for CRS Studied
Bilateral Cochlear Implants Improve Spatial Acuity
Can bilateral cochlear implantation, provided at a time of neural plasticity, produce normal or near-normal spatial hearing skills in young children?
Background: Spatial hearing skills improve speech understanding, especially in the presence of background noise. Children entirely dependent on unilateral cochlear implants do not develop significant sound localization skills compared with normal hearing children. Preliminary data suggest that early implantation with bilateral cochlear implants, either in a simultaneous or sequential fashion, allows users to develop better sound localization skills.
Study design: Prospective comparison of three groups of children aged 26 to 36 months: 1) normal hearing controls; 2) unilateral cochlear implant users and 3) bilateral cochlear implant users. Testing compared patients in their ability to identify the minimal audible angle of a sound source varied by 10 degrees. In addition, the unilateral cochlear implant users were compared with the bilateral cochlear implant users in correction identification of a sound source with a fixed angle of +/- 50 degrees.
Setting: Academic medical center: Waisman Center, University of Wisconsin-Madison.
Synopsis: Eight children with normal hearing (NH), 12 with a unilateral cochlear implant (UCI), and 27 with bilateral cochlear implants (BICI) were tested for minimal audible angle (MAA) using an array of speakers placed at 10-degree intervals and spanning 140 degrees of arc. The group of children with normal hearing had an MAA with a mean of 14.5 degrees and a range of 3.3 to 30.2 degrees. UCI children could not reach a minimum correct score at any one angle and the MAA could not be calculated. BICI children had an MAA of 30.9 degrees (range 5.7 to 69.6 degrees). For the fixed angle experiment, UCI children performed at chance and BICI children performed at one standard deviation above chance in correctly identifying a right-left discrimination with a speaker fixed at +/- 50 degrees.
In this age group, BICI children performed better than UCI children in these spatial acuity tasks. The BICI children did not perform as well as normal hearing controls. The cochlear implant children in general used a microphone placement behind the ear. For the BICI children, the signal for each device was independently controlled; there is not a commercially available binaural processor that can preserve interaural level or timing differences, which could theoretically improve performance in this task.
Bottom line: For these young children, bilateral cochlear implantation seemed to generate a significant benefit in spatial acuity tasks, compared with unilateral cochlear implant usage. Sound localization skill began to approach the level of the study participants with normal hearing. Longer usage with bilateral cochlear implants was associated with better performance.
Reference: Grieco-Calub TM, Litovsky RY. Spatial acuity in 2-to-3-year-old children with normal acoustic hearing, unilateral cochlear implants, and bilateral cochlear implants. Ear Hear. 2012;33(5):561-572.
—Reviewed by George Hashisaki, MD
SSCD Treated with Surgical Plugging
Does surgical plugging of a dehiscent superior semicircular canal affect hearing outcome?
Background: A low frequency conductive hearing loss has been associated with superior semicircular canal dehiscence (SSCD). A theoretical explanation is the presence of a mobile “third window” at the dehiscent area that allows sound pressure energy to be shunted away from the cochlea. This effect would impact air conduction thresholds but not bone conduction thresholds, thus creating an apparent conductive hearing loss.
Study design: Retrospective review of 43 cases of SSCD treated with surgical plugging of the affected superior semicircular canal. Pre-operative and post-operative audiograms were compared.
Setting: Tertiary academic medical center: Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore.
Synopsis: The study included 40 patients who underwent a total of 43 repairs of SSCD using a technique of surgical plugging of the superior semicircular canal through a middle cranial fossa approach. All patients had pre-operative and short-term (seven-to-10 day) post-operative audiograms. Thirty-two of the affected 43 ears also had audiograms at more than one month post-operatively (range, one to 15 months; median, three months).
The short-term audiograms showed a slight worsening of bone conduction thresholds across frequencies and persistence of a mild air-bone gap across frequencies. A majority of patients were noted to have fluid or blood in the middle ear.
For the ears with audiograms at longer than one month after surgery, the bone conduction thresholds improved slightly, but a decrease persisted in thresholds at 2000 and 4000 Hz. Air conduction thresholds improved, compared with the short-term audiograms, across frequencies, nearly matching the bone conduction thresholds. In comparison to pre-operative audiograms, there was improvement in the low frequency conductive hearing loss, but there was evidence of a new sensorineural hearing loss at 4000 and 8000 Hz.
Bottom line: The low frequency conductive hearing loss seen in some patients with SSCD is corrected by surgical plugging of the dehiscence. In addition, the procedure was associated with a new mild sensorineural hearing loss in 25 percent of the study participants.
Reference: Ward BK, Agrawal Y, Nguyen E, et al. Hearing outcomes after surgical plugging of the superior semicircular canal by a middle cranial fossa approach. Otol Neurotol. 2012;33(8):1386-1391.
—Reviewed by George Hashisaki, MD
Vocal Fold Paresis Following Neonatal Cardiac Surgery
What are the incidence and implications of vocal fold paresis (VFP) following congenital neonatal cardiac surgery?
Background: VFP and post-operative feeding difficulties are known complications of cardiac surgery in children, particularly in association with aortic arch interventions, the intra-operative use of transesophageal echocardiography, low birth weight, median sternotomy, use of electrocautery or prolonged intubation. Manipulation of the aortic arch places the recurrent laryngeal nerve and, thus, vocal fold function at risk.
Study design: Retrospective chart review.
Setting: Bobby R. Alford Department of Otolaryngology-Head and Neck Surgery, Baylor College of Medicine, Houston; Lillie Frank Abercrombie Section of Pediatric Cardiology, Baylor College of Medicine, Texas Children’s Hospital, Houston.
Synopsis: Previous studies noted in this article indicate a range of 1.7 percent to 67 percent for reported incidence of VFP following cardiac surgery. Of 76 neonates who underwent a median sternotomy for cardiac surgery between May 2007 and May 2008, 19.7 percent had VFP post-operatively. Almost 27 percent of the patients with aortic arch surgery had VFP, while only 4.1 percent of the patients with nonaortic arch surgery developed VFP. Patients who underwent aortic arch surgery weighed significantly less and all patients with VFP had significant morbidity related to swallowing and nutrition, requiring longer post-surgical hospitalization. The researchers did not find that post-operative VFP was associated with significantly longer intubation times. Their cohort included patients with a wide variety of complex cardiac operations, in comparison with previous studies in which a difference in intubation time was noted, which included patients who underwent patent ductus arteriosus ligation.
Bottom line: The reported incidence of VFP following cardiac surgery via median sternotomy ranges between 1.7 percent and 67 percent, depending on the type of surgery and weight of the infant. In this study, surgery requiring aortic arch manipulation had a higher incidence of complications and required longer hospitalizations.
Reference: Dewan K, Cephus C, Owczarzak V, Ocampo E. Incidence and implication of vocal fold paresis following neonatal cardiac surgery. Laryngoscope. 2012;122(12):2781-2785.
—Reviewed by Sue Pondrom
Management of Temporal Bone Defects after Oncologic Resection
What is the best way to manage defects resulting from oncologic temporal bone resection?
Background: There are limited reports regarding use of local and regional flaps versus microvascular free flaps for temporal bone reconstruction after oncologic resection. Additionally, outcomes are only sporadically documented for facial nerve repair and rehabilitation in the oncologic setting after resection.
Study design: Retrospective review.
Setting: Department of Plastic Surgery, Department of Head and Neck Surgery, Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston.
Synopsis: The authors reviewed their own experience with temporal bone reconstruction, comparing outcomes between 27 patients with regional flaps and 90 patients with microvascular free flaps. They found that operative time was shorter for reconstruction with regional flaps, as were intensive care unit and hospital stays. However, the authors said they have steered away from using local flaps because of their poor reliability and cosmetic appearance. With the exception of the temporalis muscle flap, which is useful for small defects but is sometimes unavailable, the authors have also ceased using regional pedicled flaps, because temporal bone defects are at the very limit of the arc of rotation of these flaps. The authors said nerve repairs were performed in 19 patients, 17 of which were followed for about 12 months. Of these, 71.4 percent demonstrated signs of reinnervation and 42.9 percent achieved a House-Brackmann score of three or better. The mean time to reinnervation was 7.9 months.
Bottom line: Regional flaps, such as the temporalis muscle flap, are useful for small defects, while free flaps are indicated for large defects as well as in cases of prior surgery for radiation. Facial nerve repair should be attempted in every patient with less than 12 months of complete paralysis, even in the setting of advanced age, expected post-operative radiation or pre-existing facial nerve weakness.
Reference: Hanasono MM, Silva AK, Yu P, Skoracki RJ, Sturgis EM, Gidley PW. Comprehensive management of temporal bone defects after oncologic resection. Laryngoscope. 2012;122(12):2663-2669.
—Reviewed by Sue Pondrom
Pattern of Active HPV Expression Correlates to Disease Course
What is the behavior of primary and metastatic oropharyngeal squamous cell carcinoma (OPSCC) with respect to active human papillomavirus (HPV)?
Background: Carcinogens contributing to head and neck squamous cell carcinoma (HNSCC) have been thought to result in the progressive accumulation of adverse genetic modifications leading to loss of cell cycle control and/or derangements in DNA repair. Although the overall incidence of smoking has decreased over the last two decades, the incidence of HNSCC has remained stable, correlating with an increased incidence of squamous cell carcinoma in oropharyngeal subsites. This increase is thought to be due to oncogenic HPV.
Study design: Experimental study.
Setting: Department of Otorhinolaryngology, Department of Experimental Pathology, Department of Laboratory Medicine and Pathology and Division of Anatomic Pathology, Mayo Clinic, Rochester, Minnesota.
Synopsis: Patient-matched tumor, normal and metastatic tissue was gathered from 42 OPSCC patients, evaluated and tested with various methodologies. When comparing the presence of HPV16 DNA in tumor, metastatic and normal tissue by in situ hybridization (ISH), perfect correlation was found at all subsites. However, active infections determined by HPV16 E6 and E7 expression, using quantitative polymerase chain reaction (qPCR) or p16 detection by immunohistochemistry (IHC), were present only in primary and metastatic tissue. No such correlation was found in normal tissue when compared to primary or metastatic tissue. The authors noted that their findings support the idea of latent virus in adjacent normal tissue, as manifested by HPV ISH positivity, without E6, E7 or p16 activity by qPCR.
Bottom line: There is a clear pattern of active HPV expression that correlates to the course of OPSCC.
Reference: Laborde RR, Janus JR, Olsen SM, et al. Human papillomavirus in oropharyngeal squamous cell carcinoma: assessing virus presence in normal tissue and activity in cervical metastasis. Laryngoscope. 2012;122(12):2707-2711.
—Reviewed by Sue Pondrom
Safety of Antimicrobial Photodynamic Therapy for CRS Studied
Is antimicrobial photodynamic therapy (aPDT) a safe treatment for chronic recurrent sinusitis (CRS)?
Background: CRS is one of the most common chronic conditions in the U.S., affecting an estimated 37 million people. CRS is also considered a significant factor in exacerbating asthma, chronic lung diseases, eczema, otitis media and chronic fatigue. However, there is no standard therapy to control and cure CRS. Treatment with aPDT, a noninvasive, nonantibiotic broad-spectrum antimicrobial treatment, must be evaluated to be sure that it will not result in histologic damage to the sinus ciliated respiratory epithelium.
Study design: Experimental study with EpiAirway.
Setting: Department of Otolaryngology, Head and Neck Surgery, University of Minnesota, Minneapolis; PhotoBiologix, Inc., Minneapolis; Abbott Northwestern Hospital, Department of Pathology, Minneapolis; Sinuware, Inc., Bothell, Washington.
Synopsis: EpiAirway AFT-100-AFB (MatTek Corp., Ashland, Mass.), a full thickness, human, ciliated mucus-forming, respiratory mucosa culture with 21 days growth without antibacterials or antifungals was used as an in vitro airway tissue model that originates from normal, human-derived, tracheal/bronchial epithelial cells cultured to form a three-dimensional, pseudostratified, ciliated, highly differentiated model closely resembling the epithelial tissue of the respiratory tract. The study was designed to mimic an aPDT human sinus treatment with topical application. Samples from seven study groups were evaluated by a board-certified human pathologist. Persistence of ciliated respiratory epithelium was seen in all specimens. There were no specific histomorphological findings.
Bottom line: The antimicrobial treatment aPDT is not associated with significant histological ciliary or epithelial injury and is safe for human treatment.
Reference: Biel MA, Jones JW, Pedigo L, Gibbs A, Loebel N. The effect of antimicrobial photodynamic therapy on human ciliated respiratory mucosa. Laryngoscope. 2012;122(12):2628-2632.
—Reviewed by Sue Pondrom