Name: the miniature pig: a large animal model for cochlear implant research
Uploaded: 2022-07-28T15:00:00
Description: Watch this Scientific Journal Video about The Miniature Pig: A Large Animal Model for Cochlear Implant Research at JoVE.com

This study was funded by grants from the National Natural Science Foundation of China (Nos. 81970890) and the Chongqing Scientific Research Institution Performance incentive project (Nos. 19540). We thank Anandhan Dhanasingh and Zhi Shu from the MED-EL company for their support.

All procedures and animal surgeries were conducted according to the guidelines of the Ethics Committee of the PLA General Hospital and were approved.
1. Anesthesia and surgical preparation
<ol>
	<li>Inject the pig (male, 2 months old, 5 kg) muscularly with tiletamine and zolazepam with a dosage of 10-15 mg/kg and intubate it with a 5.5-French endotracheal tube. Maintain anesthesia by ventilator-assisted respiration with isofluorane inhalation. Monitor the oxygen saturation (...

<ol>
	<li>World report on hearing. World Health Organization Available from: <a target="_blank" href="https://www.who.int/publications/i/item/world-report-on-hearing">https://www.who.int/publications/i/item/world-report-on-hearing</a> (2021)</li><li>Lee, S. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+course+of+residual+hearing+preservation+with+a+slim,+modiolar+cochlear+implant+electrode+array.">Natural course of residual hearing preservation with a slim, modiolar cochlear implant electrode array.</a> American Journal of Otolaryngology. 43 (2), 103382 (2022).</li><li>Lorens, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Binaural+advantages+in+using+a+cochlear+implant+for+adults+with+profound+unilateral+hearing+loss.">Binaural advantages in using a cochlear implant for adults with profound unilateral hearing loss.</a> Acta Oto-Laryngologica. 139 (2), 153-161 (2019).</li><li>Lally, J. W., Adams, J. K., Wilkerson, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+cochlear+implantation+in+the+elderly.">The use of cochlear implantation in the elderly.</a> Current Opinion in Otolaryngology &amp; Head and Neck Surgery. 27 (5), 387-391 (2019).</li><li>Rhodes, R. M., Tsai Do, B. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Future+of+implantable+auditory+devices.">Future of implantable auditory devices.</a> Otolaryngologic Clinics of North America. 52 (2), 363-378 (2019).</li><li>Colesa, D. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+chronically-implanted+mouse+model+for+studies+of+cochlear+health+and+implant+function.">Development of a chronically-implanted mouse model for studies of cochlear health and implant function.</a> Hearing Research. 404, 108216 (2021).</li><li>Toulemonde, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+the+efficacy+of+dexamethasone-eluting+electrode+array+on+the+post-implant+cochlear+fibrotic+reaction+by+three-dimensional+immunofluorescence+analysis+in+Mongolian+gerbil+cochlea.">Evaluation of the efficacy of dexamethasone-eluting electrode array on the post-implant cochlear fibrotic reaction by three-dimensional immunofluorescence analysis in Mongolian gerbil cochlea.</a> Journal of Clinic Medicine. 10 (15), 3315 (2021).</li><li>King, J., Shehu, I., Roland, J. T., Svirsky, M. A., Froemke, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+physiological+and+behavioral+system+for+hearing+restoration+with+cochlear+implants.">A physiological and behavioral system for hearing restoration with cochlear implants.</a> Journal of Neurophysiology. 116 (2), 844-858 (2016).</li><li>Chen, M., Min, S., Zhang, C., Hu, X., Li, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+extracochlear+multichannel+electrical+stimulation+to+relieve+tinnitus+and+reverse+tinnitus-related+auditory-somatosensory+plasticity+in+the+cochlear+nucleus.">Using extracochlear multichannel electrical stimulation to relieve tinnitus and reverse tinnitus-related auditory-somatosensory plasticity in the cochlear nucleus.</a> Neuromodulation. , (2021).</li><li>Yi, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Miniature+pigs:+A+large+animal+model+of+cochlear+implantation.">Miniature pigs: A large animal model of cochlear implantation.</a> American Journal of Translational Research. 8 (12), 5494-5502 (2016).</li><li>Vollmer, M., Beitel, R. E., Schreiner, C. E., Leake, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Passive+stimulation+and+behavioral+training+differentially+transform+temporal+processing+in+the+inferior+colliculus+and+primary+auditory+cortex.">Passive stimulation and behavioral training differentially transform temporal processing in the inferior colliculus and primary auditory cortex.</a> Journal of Neurophysiology. 117 (1), 47-64 (2017).</li><li>Sunwoo, W., Delgutte, B., Chung, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+bilateral+cochlear+implant+stimulation+partially+restores+neural+binaural+sensitivity+in+neonatally-deaf+rabbits.">Chronic bilateral cochlear implant stimulation partially restores neural binaural sensitivity in neonatally-deaf rabbits.</a> The Journal of Neuroscience. 41 (16), 3651-3664 (2021).</li><li>Mantokoudis, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lamb+temporal+bone+as+a+surgical+training+model+of+round+window+cochlear+implant+electrode+insertion.">Lamb temporal bone as a surgical training model of round window cochlear implant electrode insertion.</a> Otology &amp; Neurotology. 37 (1), 52-56 (2016).</li><li>de Abajo, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+implantation+and+reimplantation+of+cochlear+implant+electrodes+in+an+in+vivo+animal+experimental+model+(Macaca+fascicularis).">Effects of implantation and reimplantation of cochlear implant electrodes in an in vivo animal experimental model (Macaca fascicularis).</a> Ear and Hearing. 38 (1), 57-68 (2017).</li><li>Johnson, L. A., Della Santina, C. C., Wang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+bone+characterization+and+cochlear+implant+feasibility+in+the+common+marmoset+(Callithrix+jacchus).">Temporal bone characterization and cochlear implant feasibility in the common marmoset (Callithrix jacchus).</a> Hearing Research. 290 (1-2), 37-44 (2012).</li><li>Yin, P., Li, S., Li, X. J., Yang, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+pathogenic+insights+from+large+animal+models+of+neurodegenerative+diseases.">New pathogenic insights from large animal models of neurodegenerative diseases.</a> Protein &amp; Cell. , (2022).</li><li>Yu, S. M., Wang, C. W., Zhao, D. M., Zhang, Q. C., Pei, D. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Raising+and+pathogen+purification+of+Chinese+experimental+mini-pig.">Raising and pathogen purification of Chinese experimental mini-pig.</a> Laboratory Animal Science and Administration. 20, 44-46 (2003).</li><li>Guo, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+morphology+and+electrophysiology+of+the+cochlea+of+the+miniature+pig.">The morphology and electrophysiology of the cochlea of the miniature pig.</a> The Anatomical Record. 298 (3), 494-500 (2015).</li><li>Christov, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electric+compound+action+potentials+(ECAPs)+and+impedances+in+an+open+and+closed+operative+site+during+cochlear+implantation.">Electric compound action potentials (ECAPs) and impedances in an open and closed operative site during cochlear implantation.</a> Cochlear Implants International. 20 (1), 23-30 (2019).</li><li>Zhong, L. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inner+ear+structure+of+miniature+pigs+measured+by+multi-planar+reconstruction+techniques.">Inner ear structure of miniature pigs measured by multi-planar reconstruction techniques.</a> American Journal of Translational Research. 10 (3), 709-717 (2018).</li><li>The Lancet. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hearing+loss:+An+important+global+health+concern.">Hearing loss: An important global health concern.</a> The Lancet. 387 (10036), 2351 (2016).</li><li>Guo, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cochlear+implant-based+electric-acoustic+stimulation+modulates+neural+stem+cell-derived+neural+regeneration.">Cochlear implant-based electric-acoustic stimulation modulates neural stem cell-derived neural regeneration.</a> Journal of Materials Chemistry B. 9 (37), 7793-7804 (2021).</li><li>Gabrielpillai, J., Geissler, C., Stock, B., St&#246;ver, T., Diensthuber, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+hormone+promotes+neurite+growth+of+spiral+ganglion+neurons.">Growth hormone promotes neurite growth of spiral ganglion neurons.</a> Neuroreport. 29 (8), 637-642 (2018).</li><li>Li, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guided+growth+of+auditory+neurons:+Bioactive+particles+towards+gapless+neural+-+electrode+interface.">Guided growth of auditory neurons: Bioactive particles towards gapless neural - electrode interface.</a> Biomaterials. 122, 1-9 (2017).</li><li>Wille, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+neuronal+guidance+fibers+for+stimulating+electrodes:+Basic+construction+and+delivery+of+a+growth+factor.">Development of neuronal guidance fibers for stimulating electrodes: Basic construction and delivery of a growth factor.</a> Frontiers in Bioengineering and Biotechnology. 10, 776890 (2022).</li></ol>

Around 15% of the world's population have some degree of hearing loss, and over 5% have disabling hearing loss21. CI provision is the most efficient treatment for both adult and pediatric patients with severe and profound sensorineural hearing loss. As the first successful implantable cranial nerve stimulator, over the past 2 decades, CIs have offered thousands of people with hearing loss the opportunity to return to the world of sound and (re)integrate into mainstream society. Even though CIs are...

According to the World Health Organization (WHO), over 1 billion people are at risk of hearing loss globally, and it is estimated that, by 2050, one out of four people will suffer hearing loss1. Over the last 2 decades, CIs have been the most effective intervention for people with permanent severe and profound sensorineural hearing loss (SNHL). A CI converts physical signals of sound into bioelectrical signals that stimulate the spiral ganglion neurons (SGNs), bypassing hair cells. Over time, the indications for a CI have been broadened so that they now include people with residual hearing, unilateral hearing loss, and very old or young people2,3,4. Meanwhile, totally implantable CIs and advanced arrays have been developed5. There is, however, no economically feasible large animal model for investigating the electrophysiology and histopathology of the inner ear with a CI. This lack of a large animal model limits research seeking to improve CIs and gain insights into the electrophysiological impact of CIs on the inner ear.
Several rodent animal models have been applied in CI research, such as mouse6, gerbil7, rat8, and guinea pig9; however, the characteristics of morphology and electrophysiological responses are different from that in humans. Cochlear structures of animal models traditionally used for CI studies, such as cats, guinea pigs, and other animals, differ greatly from those of human cochlear structures10. Although array insertion has been conducted on cats11 and rabbits12, because of their smaller cochleae, this was done with arrays that were not designed for use in humans. Several large animal models have also been explored for CI. Lambs are well suited as a training model for atraumatic cochlear implantation, but the smaller size of the cochlea makes full array insertion impossible13. Primates might be the most suitable animals for CI research because of their anatomical similarity to humans14,15; however, the sexual maturity of monkeys is delayed (4-5 years), the gestation period is up to about 165 days, and each female usually produces only one offspring per year16. These reasons, and the expensive cost, hinder the extensive application of primates in CI research.
In contrast, pigs reach sexual maturity at 5-8 months and have a gestation period of ~114 days, making pigs more accessible for CI research as a large animal model16. Bama mini pigs (mini-pigs) originated from a small-sized pig species in China in 1985, whose genetic background is well understood. They are characterized by an inherent small size, early sexual maturity, rapid breeding, and ease of management17. The mini-pig is an ideal model for otology and audiology because of its similarity to humans in morphology and electrophysiology18. The scala tympani length of a Bama mini-pig is 38.58 mm, which is close to the 36 mm length in humans10. The mini-pig cochlea has 3.5 turns, which is similar to the 2.5-3 turns seen in humans10. In addition to morphology, the electrophysiology of Bama mini-pigs is also highly similar to that of humans18. Therefore, in the present study, we inserted arrays designed for human use into the mini-pig cochlea via the round window membrane and followed a similar surgical approach to that used in human CI recipients. Intraoperative ECAP measurements were applied to evaluate the procedure. The process we describe herein could be used both for preclinical translational research associated with CIs and as a platform for resident training.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.5 mm diamond burr</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>1 mm diamond burr</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>5 mm diamond burr</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2-0 suture silk</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3D Slicer image computing platform</td>
			<td></td>
			<td></td>
			<td>3D reconstruction of CT image</td>
		</tr>
		<tr>
			<td>Alcohol</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bipolar cautery</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bipolar electrocoagulation</td>
			<td></td>
			<td></td>
			<td>Stop bleeding</td>
		</tr>
		<tr>
			<td>CI designed for human use (CONCERTO FLEX28)</td>
			<td>MED-EL</td>
			<td>&#160;Concerto F28</td>
			<td></td>
		</tr>
		<tr>
			<td>Dressing forceps</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ECG monitor</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Iodine tincture</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td></td>
			<td></td>
			<td>3.6 mL/h</td>
		</tr>
		<tr>
			<td>Laryngoscope</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>MAESTRO Software</td>
			<td>MED-EL</td>
			<td></td>
			<td>Measure ECAP responses</td>
		</tr>
		<tr>
			<td>Micro forceps</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micro spatula</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mosquito forceps</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Needle holder</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Needle probe</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Negative pressure suction device</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Otological surgical instruments&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Respiratory Anesthesia Machine</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel with blade No. 15</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Scissors</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Shaver</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Stimulation device (MAX Programming Interface)</td>
			<td>MED-EL</td>
			<td></td>
			<td>Measure ECAP responses</td>
		</tr>
		<tr>
			<td>Surgery microscope</td>
			<td>Leica</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical drill</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical Power Device</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tiletamine and zolazepan</td>
			<td></td>
			<td></td>
			<td>10-15 mg/kg</td>
		</tr>
		<tr>
			<td>Tissue forceps</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Trachea cannula</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

the miniature pig: a large animal model for cochlear implant research

Cochlear implants (CI) are the most effective method to treat people with severe-to-profound sensorineural hearing loss. Although CIs are used worldwide, no standard model exists for investigating the electrophysiology and histopathology in patients or animal models with a CI or for evaluating new models of electrode arrays. A large animal model with cochlea characteristics similar to those of humans may provide a research and evaluation platform for advanced and modified arrays before their use in humans. 
To this end, we established standard CI methods with Bama mini-pigs, whose inner ear anatomy is highly similar to that of humans. Arrays designed for human use were implanted into the mini pig cochlea through a round window membrane, and a surgical approach followed that was similar to that used for human CI recipients. Array insertion was followed by evoked compound action potential (ECAP) measurements to evaluate the function of the auditory nerve. This study describes the preparation of the animal, surgical steps, array insertion, and intraoperative electrophysiological measurements. 
The results indicated that the same CI used for humans could be easily implanted in mini-pigs via a standardized surgical approach and yielded similar electrophysiological outcomes as measured in human CI recipients. Mini-pigs could be a valuable animal model to provide initial evidence of the safety and potential performance of novel electrode arrays and surgical approaches before applying them to human beings.

The integrity (Figure 4A)&#160;and impedances (Figure 4B) of the CI were confirmed by MAESTRO Software. ECAP results showed that all 12 electrodes demonstrated good neural responses (Figure 4C), meaning the electrode array was well attached to the cochlear axis and stimulated the auditory nerve. Figure 5 demonstrates postoperative 3D reconstructed electrode coils in the right cochlea. The array did not ...

Watch this Scientific Journal Video about The Miniature Pig: A Large Animal Model for Cochlear Implant Research at JoVE.com

The Miniature Pig: A Large Animal Model for Cochlear Implant Research

Miniature pigs (mini-pigs) are an ideal large animal model for research into cochlear implants. Cochlear implantation surgery in mini-pigs can be utilized to provide initial evidence of the safety and potential performance of novel electrode arrays and surgical approaches in a living system similar to human beings.

Cochlear implants (CI) are the most effective method to treat people with severe-to-profound sensorineural hearing loss. Although CIs are used worldwide, ...

Cochlear implantation surgery in mini piggers can be utilized to provide intentional evidence of the safety and potential performance of novel electrode areas and the surgical approach in a living system similar to human beings. Mini piggers are an endo lab animal model for research into cochlear implants. Cochlear implants on mini piggers provide an individual platforms for transplant people with severe to profound sensory neuro hearing loss.Moreover, it also provides a surgery loss of gene therapy for hearing loss in big animal model. As they are significant and similar, in morphology and structure of osculatory organs between mini piggers and human beings. This surgery method clarifies the procedure and is helpful for beginners.Demonstrating the procedure will be Ji Xiaojun and Otolaryngology professor and Luo Yi a chief physician from my laboratory. After anesthetizing two months old male pig, monitor the oxygen saturation breathing and heart rate using the pulse oximetry clamp of an ECG monitor connected to the pig's tongue. Place the mini pig in the left lateral position.Keep the eyes closed using a medical patch to prevent dryness. Shave the 10 centimeter surgical area around the ear lobe. Disinfect the skin with three alternating swabs of iodine and alcohol.Then cover the surgical area with sterile surgical drapes. Cover the microscope with a sterile plastic sleeve and remove the parts covering the eye pieces and objective. Locate the surface projection site of the cochlea one centimeter behind the posterior auricular sulcus at the level of the ear lobe.Then, using a scalpel, make a 5 centimeter long postauricular incision with the projection site as the center. Divide the subcutaneous tissue, parotid gland and sternocleidomastoid muscle with micro scissors to expose the surface of the mastoid bone. For cortical mastoidectomy, drill the mastoid at the surface projection of the cochlea on the mastoid bone to the external auditory canal or EAC which is dense and pale blue.Be careful not to damage the pale or reddish vertical segment of the facial nerve dorsal to the EAC to avoid bleeding. Next, expose the tympanum by drilling the bone surrounding the posterior bony EAC. Separate the skin of the EAC and the facial nerve with a hypodermic needle to avoid damaging the facial nerve.Carefully push the skin of the EAC away to expose the tympanum including the ossicular chain and round window niche. Then, remove the round window niche with a small diamond bur and keep continuous suction irrigation to expose the basal turn of the cochlea and round window membrane. Separate the cranial parietal muscle to form a pocket for the receiver.Place the internal receiver package in the muscular pocket and fix it with a fixation suture. Next, insert the electrode array connected to a receiver fixed in a muscular pocket by opening the round window membrane with a sharp microsurgical knife and inserting the array using micro forceps slowly, steadily and continuously in relationship to the modiolus of the cochlea. For evoked compound action potential or ECAP measurements, magnetically connect to the cochlear implant or CI coil to the CI receiver through the skin.Then using Maestro software, confirm the integrity of the CI and check the electrode impedance for all channels before ECAP measurements using the telemetry function of the CI.To conduct ECAP measurement, select the ECAP module. Then, stimulate all 12 electrodes for ECAP measurements using biphasic stimuli of 30 microseconds phase duration with an alternating polarity paradigm averaging over 25 iterations in a stimulation rate of 45.1 pulses per second. The integrity and impedances of the CI were confirmed by Maestro software.ECAP results demonstrated that all 12 electrodes showed good neural responses indicating that the electrode array was well attached to the cochlear axis and stimulated the auditory nerve. The post-operative three-dimensional reconstructed electrode coils in the right cochlea are shown. The electrode array was coiled in the basal turn of the cochlea in the electrodes were rendered in green.Further, three-dimensional reconstruction demonstrates that the electrode array was spirally coiled in the cochlea. The most important thing is to expose the vessel tint of the cochlear and run window member and inside the electrode airways in the protocol. After ace development is technically pales away for combined gene therapy and cochlear implants to treat profound sensor neuro hearing loss in human beings.

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An Isolated Working Heart System for Large Animal Models

Since its introduction in the late 19th century, the Langendorff isolated heart perfusion apparatus, and the subsequent development of the working heart ...

Techniques for Processing Eyes Implanted with a Retinal Prosthesis for Localized Histopathological Analysis: Part 2 Epiretinal Implants with Retinal Tacks

Retinal prostheses for the treatment of certain forms of blindness are gaining traction in clinical trials around the world with commercial devices ...

A Surgical Procedure for Resecting the Mouse Rib: A Model for Large-Scale Long Bone Repair

This protocol introduces researchers to a new model for large-scale bone repair utilizing the mouse rib. The procedure details the following: preparation ...

Surgical Angiogenesis in Porcine Tibial Allotransplantation: A New Large Animal Bone Vascularized Composite Allotransplantation Model

Segmental bone loss resulting from trauma, infection malignancy and congenital anomaly remains a major reconstructive challenge. Current therapeutic ...

Cochlear Implantation in the Guinea Pig

Cochlear implants are highly efficient devices that can restore hearing in subjects with profound hearing loss. Due to improved speech perception ...

Assessment of Plasma Coagulation on Liver Tissue in a Large Animal Model In Vivo

Assessment of Plasma Coagulation on Liver Tissue in a Large Animal Model In Vivo

Plasma coagulation as a form of electrocautery is used in liver surgery for decades to seal the large liver cut surface after major hepatectomy to prevent ...

Ferric Chloride-induced Canine Carotid Artery Thrombosis: A Large Animal Model of Vascular Injury

Occlusive arterial thrombosis leading to cerebral ischemic stroke and myocardial infarction contributes to ~13 million deaths every year globally. Here, ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...