John J. Zappia

Batch fabricated thin-film electrodes for stimulation of the central auditory system

Silicon micromachining and thin-film technology were used to fabricate iridium stimulating arrays which can be used to excite discrete volumes of the central nervous system. Silicon multichannel probes with thicknesses ranging from 1 to 40 mu m and arbitrary two-dimensional shape can be fabricated using a high-yield, circuit-compatible process. Iridium stimulating sites are shown to have similar characteristics to iridium wire electrodes. Accelerated pulse testing with over eight million 100 mu A biphasic current pulses on 8000 mu m/sup 2/ sites demonstrated the long-term stability of iridium and activated iridium sites. In vivo tests were performed in the central auditory pathways to demonstrate neural activation using the devices. These tests show a selective activation both as a function of site separation and site size.<<ETX>>

Evaluation of the temporal bones of a multichannel cochlear implant patient.

In this report we detail the temporal bone findings of a 57-year-old patient who underwent placement of a Nucleus 22-channel electrode 7 months prior to his death. Audiometric testing postoperatively demonstrated suprasegmental speech cue discrimination only. Histologic evaluation of the cochleas revealed significant sensorineural survival except in the region of the basal turn of the implanted cochlea adjacent to the implant. There was no significant pathologic condition attributable to the operation or the electrode in areas remote from the basal turn of the cochlea.

Facial nerve paresis as the presenting symptom of leukemia

Leukemic involvement of the temporal bone is not uncommon and may present in a variety of ways including auricular or external canal skin lesions, red or thick tympanic membrane, middle ear effusions, otitis media, hearing loss or mastoiditis. Symptomatic facial nerve involvement, on the other hand, is extremely unusual. We discuss a pediatric patient whose sudden onset facial nerve paresis was the presenting symptom that led to her diagnosis of leukemia. At the time of mastoidectomy, a granulocytic sarcoma or chloroma was noted to be overlying the VIIth nerve.

Intraoperative auditory monitoring in acoustic neuroma surgery

Intraoperative auditory monitoring is a useful adjunct that is currently evolving. Near-field monitoring techniques such as electrocochleography and direct eighth nerve compound action potential are being used more frequently. The use of these two techniques is compared in 26 patients undergoing hearing preservation acoustic neuroma resection. Overall, 9 (35%) of the 26 patients had their hearing preserved. Three (23%) of the 13 with electrocochleography monitoring and 6 (46%) of the 13 with direct compound action potential monitoring had hearing preserved after surgery. Although there was a suggestion of improved results with direct compound action potential monitoring, the results were not statistically different. It was noted that lack of electrical response at the completion of the procedure (regardless of monitoring technique) was correlated with poor postoperative hearing, whereas the presence of a waveform at termination in no way predicted satisfactory postoperative hearing. The two techniques and their advantages and disadvantages are discussed.

Chronic skull-anchored percutaneous implants in non-human primates

Three groups of chronic, skull-anchored, percutaneous implants differing in materials, design and surgical procedures used for implantation, were tested in macaque monkeys in conjunction with studies of an inner ear stimulation device. Implants from the first two groups in which high-speed drilling methods and stainless steel materials were used, showed a high percentage of failures during the first 3 months after implantation of the percutaneous connector. Implants in the third group, in which measures were taken to preserve living bone tissue, all survived for greater than 7 months. Probable factors relating to implant survival are care of the bone during surgery, postsurgical mechanical trauma, materials and other details of the surgical procedure.

Modified resurfacing repair for superior semicircular canal dehiscence

Superior semicircular canal dehiscence (SSCD) was first described by Minor et al in 1998 and is identified by an incomplete bony covering of the superior semicircular canal (SSC). SSCD can result in a variety of auditory or vestibular symptoms that can be debilitating enough in certain patients to consider surgical intervention. The surgical approach options include middle cranial fossa (MCF) and transmastoid. The SSCD can be addressed either by resurfacing, with maintenance of the lumen, or plugging with occlusion of the SSC on each side of the dehiscent canal to isolate and seal the lumen. We believe that resurfacing of the SSC decreases the risk to the labyrinth and have favored a resurfacing technique via an MCF approach with a layer of fascia directly over the SSCD and a small hydroxyapatite plate between the fascia and the dura. Those who favor plugging techniques have reported resurfacing failures possibly attributable to resorption or migration of the fascia or bone. Sensorineural hearing loss is a known complication of the plugging of any semicircular canal. In addition, plugging of the SSC can lead to vestibular dysfunction beyond the SSC itself. A variety of other materials have been reported to be successful. In one of our surgical patients, the SSCD was adjacent to the superior petrosal sinus and the hydroxyapatite plate could not be placed. A piece of medium thickness (0.020 inch) silicone elastomer (Silastic; Dow Corning Corporation, Midland, MI) was placed instead. When this patient was relieved of symptoms postoperatively, this technique was used on subsequent patients.

Evaluation of a Silicon-Substrate Modiolar Eighth Nerve Implant in a Guinea Pig

The availability of thin-film multichannel electrodes provides new possibilities for implantation and direct stimulation of the modiolar portion of the auditory nerve. Electrodes in direct contact with the auditory nerve should be functional at lower thresholds and might require fewer remaining neurons for stimulation compared to electrodes in the scala tympani. This strategy would also provide close contact with neural elements subserving a greater frequency range. Implantation of the eighth nerve may also be advantageous in profoundly deaf subjects who lack an implantable scala tympani. In this study we evaluated the effect of surgical implantation and chronic placement of a silicon substrate implant in the modiolar portion of the auditory nerve of the guinea pig. Of six chronically implanted ears, five showed changes limited to the loss of spiral ganglion cells in the canal of Rosenthal, immediately adjacent to the Implant. The sixth ear showed more extensive cochlear alteration in a pattern suggestive of vascular injury. In separate acute experiments, implants were placed in the modiolar portion of the auditory nerve and electrophysiologic analysis was performed. Middle latency responses with good morphology were obtained at thresholds below those found with scala tympani implants. Input-output functions exhibited a plateau in response amplitude at stimulus levels below thresholds for seventh or vestibular portion of the eighth nerve. Further modifications of the modiolar portion of the auditory nerve electrode design will include development of an electrode interconnect that will allow chronic implantation with stimulation.

Signet-ring cell adenocarcinoma metastatic to the maxillary sinus

Signet-ring cell variant is a rare type of adenocarcinoma that has been reported in the paranasal sinuses and in other areas, most commonly the gastrointestinal tract. We describe a patient with signet-ring cell adenocarcinoma of the maxillary sinus who had dental and facial pain. Further evaluation revealed that the lesion was metastatic from an esophageal primary lesion. The unusual nature of this cell type and the importance of careful evaluation to exclude the possibility of these lesions representing metastatic lesions is discussed.

Patient, disease, and outcome characteristics of benign paroxysmal positional vertigo with and without Meniere’s disease

Abstract Background: Meniere’s disease (MD)-associated benign paroxysmal positional vertigo (BPPV) is complex and difficult to diagnose, and reports of its prevalence, pathologic features and outcomes are sparse and conflicting. Objective: Report disease characteristics and outcomes associated with the presence of MD in patients with BPPV. Materials/methods: A retrospective study of patients with BPPV between 2007 and 2017 at a single, high-volume institution. Results: Of 1581 patients with BPPV identified, 7.1% had MD and 71.9% of those patients had BPPV in the same ear(s) as MD. Patients with MD were more likely to have lateral semicircular canalithiasis (11.6% vs. 5.5%, p = .009) and multiple canalithiasis (7.1% vs. 2.5%, p = .005). MD was associated with an increased rate of resolution of BPPV (p = .008) but also increased time to resolution (p = .007). There was no association between MD and recurrence of BPPV. Conclusions: MD is associated with lateral canalithiasis. Contrary to prior reports, BPPV in MD can affect either ear and was not associated with poorer outcomes than idiopathic BPPV. Significance: The largest series to date investigating disease and outcome characteristics for BPPV in MD is presented. These data inform diagnosis and expectations in the management of these complex patients.

FESS Malpractice Risk Factors Identified Using Case-Controls

Objective: Complications related to functional endoscopic sinus surgery are well documented. These complications will, in some instances, lead to claims of medical malpractice. This study seeks to preoperatively identify both patient and procedural characteristics which are more likely to result in adverse events. This may then allow them to develop risk management strategies as they pertain to functional endoscopic sinus surgery. Method: Case control study of The Doctors Company closed claims involving functional endoscopic sinus surgery between 2005-2009. These were then compared with a control group of 196 survey responses sent by The Doctors Company in 2011 to insured otolaryngologists. Results: A total of 17 claims were closed from 2005-2009. There was no significant age difference in the claims group and controls. Age greater than 60 inferred a 2.8-fold increase in risk of a closed claim (P = .09). The lack of polyps was associated with an increased risk of a claim (P = .04). All claims involved surgery that included at least an ethmoidectomy. The use of powered instrumentation was not statistically significant. Revision surgery was associated with a 13-fold increase in risk of a claim (P = .05). Conclusion: The present article illustrates the utility of a case control method to identify scenarios that are more likely to result in malpractice claims. Identification of risk factors preoperatively has the potential to help avoid complications and, thus, lawsuits. This methodology may be useful when examining other surgical procedures as well.