Patrick J. Antonelli

Impact of engineered surface microtopography on biofilm formation of Staphylococcus aureus

The surface of an indwelling medical device can be colonized by human pathogens that can form biofilms and cause infections. In most cases, these biofilms are resistant to antimicrobial therapy and eventually necessitate removal or replacement of the device. An engineered surface microtopography based on the skin of sharks, Sharklet AFTM, has been designed on a poly(dimethyl siloxane) elastomer (PDMSe) to disrupt the formation of bacterial biofilms without the use of bactericidal agents. The Sharklet AFTM PDMSe was tested against smooth PDMSe for biofilm formation of Staphylococcus aureus over the course of 21 days. The smooth surface exhibited early-stage biofilm colonies at 7 days and mature biofilms at 14 days, while the topographical surface did not show evidence of early biofilm colonization until day 21. At 14 days, the mean value of percent area coverage of S. aureus on the smooth surface was 54% compared to 7% for the Sharklet AFTM surface (p<0.01). These results suggest that surface modification of indwelling medical devices and exposed sterile surfaces with the Sharklet AFTM engineered topography may be an effective solution in disrupting biofilm formation of S. aureus.

Radiation therapy and hearing loss.

A review of literature on the development of sensorineural hearing loss after high-dose radiation therapy for head-and-neck tumors and stereotactic radiosurgery or fractionated stereotactic radiotherapy for the treatment of vestibular schwannoma is presented. Because of the small volume of the cochlea a dose-volume analysis is not feasible. Instead, the current literature on the effect of the mean dose received by the cochlea and other treatment- and patient-related factors on outcome are evaluated. Based on the data, a specific threshold dose to cochlea for sensorineural hearing loss cannot be determined; therefore, dose-prescription limits are suggested. A standard for evaluating radiation therapy-associated ototoxicity as well as a detailed approach for scoring toxicity is presented.

Diagnostic Yield of High-Resolution Computed Tomography for Pediatric Sensorineural Hearing Loss†

Objectives/Hypothesis: In recent years, relatively subtle inner ear anomalies have become apparent using high‐resolution computed tomography (CT). The purpose of this study was to determine the diagnostic yield of high‐resolution CT for pediatric sensorineural hearing loss (HL) (SNHL).

The anterior subtemporal, medial transpetrosal approach to the upper basilar artery and ponto-mesencephalic junction.

OBJECTIVE To describe and anatomically analyze the amount of exposure provided by an anterior subtemporal, medial transpetrosal approach to access the upper third of the basilar artery, ventral mesencephalon, pons, and posterior cavernous sinus. PATIENTS AND METHODS The outcomes of six patients who underwent surgical treatment via the anterior subtemporal, medial transpetrosal approach at our institution during the past 2 years were reviewed. The series included three patients with subarachnoid hemorrhage from low-lying basilar apex aneurysms, one patient with intraparenchymal hemorrhage from a pontine cavernous malformation, and two patients with slowly progressive cranial neuropathies secondary to petroclival tumors. Thirty dry temporal bone specimens were also measured to quantify the height of petrous bone resection and added proximal basilar artery exposure. RESULTS The surgical exposure was greatly enhanced in each instance, allowing each lesion to be treated in a straightforward manner with minimal added morbidity (one trochlear nerve palsy, one worsening of a preexistent oculomotor nerve palsy). Our subsequent morphometric analysis indicates that an additional 1 to 1.5 cm of basilar artery, clivus, and pons exposure over that of a standard anterior subtemporal approach is provided by this technique. CONCLUSION This approach combines the wide view of the subtemporal approach with the more proximal exposure afforded by a medial petrosectomy. The widened visualization of the ventral pons and mesencephalon minimizes cranial nerve morbidity, greatly facilitates dissection of low-lying aneurysms, and provides proximal basilar artery control that would otherwise be obscured by the petrous ridge.

Bacterial biofilms may contribute to persistent cochlear implant infection.

Objectives: To determine if bacterial biofilms are present on the surface of extruding or persistently infected cochlear implants. Methods: Scanning electron microscopy was performed on cochlear implants removed from two patients because of recalcitrant infection, two implants removed secondary to device failure, and two devices that had never been implanted. Preparations were examined by experienced microbiologists for the presence of bacterial biofilms. Results: Microorganisms and amorphous extracellular debris were found on the surface of the infected cochlear implants and the implants removed because of device failure. Biofilm formation was deemed definite in one infected device and possible in the other explanted devices. The never-implanted controls demonstrated microbial contamination without exopolymeric matrix, inconsistent with biofilms. Conclusion: Bacterial biofilm formation may play a role in recalcitrant cochlear implant infections. This may have profound implications for the treatment of cochlear implant infections.

Impact of resistant pneumococcus on rates of acute mastoiditis

OBJECTIVE To determine whether the rate of acute mastoiditis is rising, specifically as a result of antibiotic-resistant strains of Streptococcus pneumoniae. METHODS A retrospective chart review of all patients with a discharge diagnosis of acute mastoiditis between July 1, 1987, and June 30, 1997, was performed at our academic, tertiary-care medical center. There were no interventions, and the main outcome measures included the number of cases of acute or coalescent mastoiditis, stratified by pathogen, per year. RESULTS The rate of acute mastoiditis as a proportion of yearly otorhinolaryngology admissions increased linearly over time (P = 0.024). Pneumococcal-related rates of acute mastoiditis, expressed as a proportion of yearly hospital and otorhinolaryngology admissions, increased linearly over time (P = 0.002, P = 0.002). All but 1 case of pneumococcal mastoiditis during the past 3 years were caused by penicillin-resistant strains. CONCLUSIONS The emergence of antibiotic-resistant S pneumoniae may be responsible for an increasing rate of acute mastoiditis.

Prospective clinical trial comparing outcome measures between Furlow and von Langenbeck Palatoplasties for UCLP.

The goal of this prospective randomized clinical trial was to compare 2 cohorts of standardized cleft patients with regard to functional speech outcome and the presence or absence of palatal fistulae. The 2 cohorts are randomized to undergo either a conventional von Langenbeck repair with intravelar velarplasty or the double-opposing Z-plasty Furlow procedure. A prospective 2 × 2 × 2 factorial clinical trial was used in which each subject was randomly assigned to 1 of 8 different groups: 1 of 2 different lip repairs (Spina vs. Millard), 1 of 2 different palatal repair (von Langenbeck vs. Furlow), and 1 of 2 different ages at time of palatal surgery (9–12 months vs. 15–18 months). All surgeries were performed by the same 4 surgeons. A cul-de-sac test of hypernasality and a mirror test of nasal air emission were selected as primary outcome measures for velopharyngeal function. Both a surgeon and speech pathologist examined patients for the presence of palatal fistulae. In this study, the Furlow double-opposing Z-palatoplasty resulted in significantly better velopharyngeal function for speech than the von Langenbeck procedure as determined by the perceptual cul-de-sac test of hypernasality. Fistula occurrence was significantly higher for the Furlow procedure than for the von Langenbeck. Fistulas were more likely to occur in patients with wider clefts and when relaxing incisions were not used.

Radiosurgery for paraganglioma of the temporal bone.

To report the outcome of patients with paraganglioma of the temporal bone treated with stereotactic radiosurgery at the University of Florida.

Cellular telephone use and risk of intratemporal facial nerve tumor.

Objectives/Hypothesis Microwave radiation exposure from cellular telephone use has been implicated in the development of intracranial tumors. The intratemporal facial nerve (IFN) is exposed to higher levels of cellular telephone radiation than intracranial tissues. The purpose of the study was to determine whether cellular telephone use is associated with an increased risk of IFN tumors.

Fetal sheep in utero hear through bone conduction

PURPOSE Although the air-conduction pathway is the principal mode of sound transmission to the inner ear, this may not be true for the fetus in utero. The fetus detects and responds to sounds in the maternal environment. Exogenous sounds can reach the fetal inner ear through the ear canal and middle ear system, bone conduction, or both. This study was designed to compare the effectiveness of these two routes of sound transmission by recording cochlear microphonic potentials from the fetus in utero in response to airborne sounds. MATERIALS AND METHODS Cochlear microphonics (CMs) recorded from one round window (RW) of fetal sheep in utero were obtained in three conditions: (1) head uncovered; (2) head covered with a neoprene hood; and (3) head covered with a neoprene hood fashioned with a hole that permitted the pinna and ear canal to be exposed. Tone bursts (0.5, 1.0, and 2.0 kHz) were delivered through a loudspeaker at high intensities (100 to 135 dB sound pressure level) to the flank of the ewe. CMs were detected with indwelling electrodes, amplified, and averaged. CM input-output functions were obtained from the fetus in each of the three conditions described above. RESULTS CMs recorded with the head uncovered were more sensitive than were the CMs recorded with the hood in place. There was no difference in sensitivity between the condition during which the head was completely covered and the condition in which the pinna and ear canal are exposed. CONCLUSION The principal mode of sound transmission into the fetal inner ear is through bone conduction.