This study was supported by Youth Fund of National Natural Science Foundation of China (Grant No. 81400460), Youth Fund of National Natural Science Foundation of China (Grant No. 81900932), and Clinical Research Plan of SHDC (Grant No. SHDC2020CR1049B).

NOTE: This study was approved and performed according to the guidelines of the ethical committee of Fudan University.
1. Anesthesia and surgical field preparation
<ol>
	<li>Induce intravenous anesthesia and perform orotracheal intubation or use a laryngeal mask.</li>
	<li>Place the patient in a supine position with the head rotated to the contralateral side.</li>
	<li>Sterilize the auricle and the external ear canal (EAC) with a povidone iodine solution; drape the surgical field with a blanket sparing the EAC.</li>
	<li>Check the optical clarity of the endoscope and adjust its white balance.</li>
	<li>Introduce the 0&#176;, 3 mm diameter, and 15 cm length endoscope into the EAC. Remove the cerumen from the EAC with microscopic forceps and sterilize the EAC with the povidone iodine solution again.</li>
</ol>
2. Establishment of a minimal invasive endaural approach
<ol>
	<li>Administer local anesthesia to the EAC by injecting 1% lidocaine with adrenaline (1:100,000) at 7 and 11-o&#39;clock positions.</li>
	<li>Under the endoscope, make a circumferential incision with a round knife from 2 to 6-o&#39;clock position, counterclockwise (right ear), approximately 8 mm from the tympanic membrane. 
	NOTE: Use povidone iodine to clean the lens of the endoscope.</li>
	<li>Raise the tympanomeatal flap with a 1 mm diameter suction tube and a small piece of gauze soaked with adrenaline (1:1,000).</li>
	<li>Under direct vision, make an intercartilaginous incision with a scalpel at the 12-o&#39;clock position, from the previously made circumferential incision towards the meatus and through the stretched intercartilaginous incisura.</li>
	<li>Make another radial incision with the scalpel at the 6-o&#39;clock position, from the previously made circumferential incision towards the meatus.</li>
	<li>Raise the flap enclosed by the medial circumferential incision and the two radial incisions outward with a curette. Check the exposure of the lateral wall of the attic and the posterior wall of the EAC. 
	NOTE: The edge of the incision can be subjected to bipolar coagulation so that it shrinks, providing better exposure.</li>
	<li>Place a self-retaining retractor to widen the meatus of the EAC and hold the lateral-based skin flap in place.</li>
</ol>
3. Bone drilling and lesion removal
<ol>
	<li>Tailor the tube of a disposable venous infusion needle to make a soft suction tube, which will be used in the bone-drilling stage. Make several side holes at its distal end with scissors (Figure 1).</li>
	<li>Cut a small section of the tube of a disposable infusion set to make an electrodrill shaft sleeve that will protect the lens of the endoscope during bone drilling. Fix the sleeve to the drill handle with a sterile transparent sticker (Figure 1).</li>
	<li>Put the distal end of the soft suction tube (with the side holes) into the tympanic cavity, and connect the other end of the tube to a vacuum aspirator.</li>
	<li>Execute bone drilling in an inside-out direction starting from the posterior part of the scutum. 
	NOTE: Here, a 1.8 mm diamond burr is used in the beginning to avoid tearing the tympanomeatal flap. After removing the posterior part of the scutum, lesions around the incudostapedial joint can be fully exposed. Drilling of the posterior lateral attic wall can be expanded If the lesion cannot be removed entirely.</li>
	<li>Instruct the assistant to irrigate the meatus of the EAC with saline continuously. 
	NOTE: If necessary, additional clearance of bone sludge can also be done intermittently with the surgical suction tube.</li>
	<li>Remove the anterior part of the lateral attic wall by bone drilling if the lesion extends anteriorly. 
	NOTE: The malleus head can be removed to facilitate the lesion removal.</li>
	<li>Perform an extended atticoantrotomy if the lesion extends further into the antrum. 
	NOTE: The whole attic and antrum can be opened to facilitate lesion removal. Sometimes, the direct approach can be applied to the retrotympanum to remove the lesion with minimal bone-drilling5. In such an approach, the surgeon stands opposite to the affected ear and uses a 45&#176; endoscope. The operating table should be tilted ~30&#176; toward the surgeon to facilitate the introduction of the endoscope and the instruments. After lesion removal, lens fogging can be observed in some patients when the constant suction is stopped. This phenomenon will disappear if the tympanic orifice of the eustachian tube is blocked by a small piece of gauze. Of note, such a phenomenon could be used to assess eustachian tube function (fogging is a sign of good function). To observe this phenomenon, the balloon should not be too tight when endotracheal intubation is established.</li>
</ol>
4. Reconstruction and closure
<ol>
	<li>Check the integrity and mobility of the ossicular chain after lesion removal. Correct ossicular abnormalities with various mature surgical techniques6.</li>
	<li>Harvest a large piece of tragus cartilage with perichondrium on both sides.</li>
	<li>On one side, detach the perichondrium from the cartilage with a round knife, leaving the perichondrium on the other side to form a cartilage-perichondrium graft. Tailor the cartilage-perichondrium graft for reconstruction.</li>
	<li>Use the cartilage-perichondrium graft and the perichondrium to reconstruct the lateral wall of the attic and the tympanic membrane. 
	NOTE: If an extended atticoantrotomy is performed, part of the cartilage-perichondrium graft can also be used to reconstruct the posterior wall of the EAC.</li>
	<li>Tailor and reposition the tympanomeatal flap and the lateral-based skin flap; pack the EAC with a gelatin sponge.</li>
	<li>Suture the intercartilaginous incision and pack it with gauze.</li>
</ol>
5. Postoperative management
<ol>
	<li>Administer intravenous antibiotics for 2 days postoperatively during hospitalization.</li>
	<li>Remove the dressing 2 days after the surgery, just before discharge.</li>
	<li>Apply oral antibiotics and ciprofloxacin drops for 2 weeks after discharge.</li>
	<li>Remove the stitches and the remaining gelatin sponge at the first visit, usually 7 to 10 days after discharge.</li>
	<li>Organize future follow-ups according to the pathology and type of surgery.</li>
</ol>

<ol>
	<li>Yong, M., Mijovic, T., Lea, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscopic+ear+surgery+in+Canada:+a+cross-sectional+study.">Endoscopic ear surgery in Canada: a cross-sectional study.</a> Journal of Otolaryngology-Head &amp; Neck Surgery. 45, 4 (2016).</li><li>Kapadiya, M., Tarabichi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+overview+of+endoscopic+ear+surgery+in+2018.">An overview of endoscopic ear surgery in 2018.</a> Laryngoscope Investigative Otolaryngology. 4 (3), 365-373 (2019).</li><li>Tseng, C. C., Lai, M. T., Wu, C. C., Yuan, S. P., Ding, Y. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscopic+transcanal+myringoplasty+for+anterior+perforations+of+the+tympanic+membrane.">Endoscopic transcanal myringoplasty for anterior perforations of the tympanic membrane.</a> JAMA Otolaryngology-Head &amp; Neck Surgery. 142, 1088-1093 (2016).</li><li>Huang, Y. B., Hu, L. L., Ren, D. D., Han, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myringoplasty+with+an+ultrathin+cartilage-perichondrium+complex+graft+versus+temporalis+fascia+graft:+a+propensity+score-matched+analysis.">Myringoplasty with an ultrathin cartilage-perichondrium complex graft versus temporalis fascia graft: a propensity score-matched analysis.</a> Otolaryngology-Head and Neck Surgery. , 19459982096540 (2020).</li><li>Presutti, L., Marchioni, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Endoscopic ear surgery: principles, indications, and techniques. , (2015).</li><li>Slater, P. W., Rizer, F. M., Schuring, A. G., Lippy, W. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Practical+use+of+total+and+partial+ossicular+replacement+prostheses+in+ossiculoplasty.">Practical use of total and partial ossicular replacement prostheses in ossiculoplasty.</a> Laryngoscope. 107 (9), 1193-1198 (1997).</li><li>Thomassin, J. M., 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=Endoscopic+ear+surgery.">Endoscopic ear surgery.</a> Annales d' Oto-laryngologie et de Chirurgie Cervico Faciale. 107 (8), 564-570 (1990).</li><li>Pollak, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscopic+and+minimally-invasive+ear+surgery:+A+path+to+better+outcomes.">Endoscopic and minimally-invasive ear surgery: A path to better outcomes.</a> World Journal of Otorhinolaryngology-Head and Neck Surgery. 3 (3), 129-135 (2017).</li><li>Dornhoffer, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retrograde+mastoidectomy.">Retrograde mastoidectomy.</a> Otolaryngologic Clinics of North America. 39 (6), 1115-1127 (2006).</li><li>Hatano, M., Ito, M., Yoshizaki, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retrograde+mastoidectomy+on+demand+with+soft-wall+reconstruction+in+pediatric+cholesteatoma.">Retrograde mastoidectomy on demand with soft-wall reconstruction in pediatric cholesteatoma.</a> Acta Oto-laryngologica. 130 (10), 1113-1118 (2010).</li><li>Vaughan, C., Jufas, N., Patel, N. P., Saxby, A. J., Kong, J. H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+"Chopstick+Drilling+Technique":+A+novel+solution+to+drilling+bone+in+endoscopic+ear+surgery.">The "Chopstick Drilling Technique": A novel solution to drilling bone in endoscopic ear surgery.</a> Clinical Otolaryngology. 44 (6), 1231-1233 (2019).</li></ol>

The authors declare that there are no conflicts of interest regarding the publication of this article.

Since the introduction of the endoscope in middle ear surgery in the 1990s7,8, endoscopic ear surgery has gained great popularity around the world. This is partially because the endoscope can provide high-quality images and help visualize poorly seen structures such as the hypotympanum and sinus tympani. Moreover, the EAC, which is a much more direct and natural approach than the retroauricular approach to the middle ear, confers the advantages of less trauma and quick recovery. The accompanying video provides a detailed protocol of endaural exclusive endoscopic atticoantrotomy using a constant-suction bone-drilling technique adopted at this hospital. The procedure mentioned above is an endoscopic modification of the inside-out transmeatal mastoidectomy (retrograde mastoidectomy), which has already been developed in the microscope era9,10. In the current technique, we retain the advantages of the primary microscopic inside-out technique, such as a direct and natural approach, less bone removal, and following the lesion along the direction of its growth. The use of the endoscope eliminates the original disadvantages such as inadequate exposure and limited visualization.
The surgical technique mentioned above provides an endoscopic solution to various middle ear lesions, especially different degrees of cholesteatoma. Bone drilling can be gradually expanded safely by following the pathology from the tympanic cavity to the attic and the antrum. Cholesteatoma in the tympanic cavity is first recognized after the elevation of the tympanomeatal flap. If the lesion extends superiorly through the tympanic isthmus to the attic, the posterior part of the scutum can be removed first. If the cholesteatoma cannot be removed entirely, drilling could be expanded posteriorly and superiorly toward the aditus and the posterior part of the attic. If the lesion further extends anteriorly, the atticotomy could be expanded by drilling the lateral attic wall anteriorly to expose the malleus head. In case of further posterior extension of the cholesteatoma into the antrum, drilling is continued posteriorly along the tegmen tympani and tegmen antri, with a typical atticoantrotomy being performed. In summary, the extent of endaural endoscopic atticoantrotomy (retrograde mastoidectomy) is flexible and based on the requirement. 
In the authors' department, this technique is mainly used in selected patients with cholesteatoma confined to the attic and the antrum, especially in the ones with sclerotic mastoid. This surgical technique can also be used to enlarge the posterior bony part of the EAC, which is quite helpful for some patients with EAC stenosis. Currently, bone drilling is a key technical challenge of endoscopic middle ear surgery. This is mainly due to the narrow feature of the EAC, which makes it almost impossible to insert multiple instruments simultaneously. In addition, the surgeon must hold the endoscope constantly in one hand, making drilling while irrigating quite difficult. When drilling is required, some surgeons advocate switching to a microscope to enable the use of both hands. Several drilling techniques have also been developed for endoscopic middle ear surgery, such as drilling in a watered field and the "chopstick" technique5,11. 
In this video, we show methods to achieve bone drilling while irrigating and suctioning at the same time. This technique has several advantages. First, it is a simple but efficient method. After establishing a tiny endaural incision and simply modifying the electrodrill handpiece, the traditional otological electrodrill can be as effective as the specially designed microdrill or an ultrasonic bone curette for bone removal in endoscopic middle ear surgery. Second, the suction tube placed in the EAC is soft and flexible, providing great agility and maneuverability that facilitates operation in tight spaces. Finally, the soft sleeve around the drill shaft is also quite useful. It can prevent the high-speed rotating shaft from damaging the lens of the endoscope. Thus, the drilling technique mentioned in this paper is practical and efficient and can be successfully adopted in endoscopic middle ear surgery.

Since the endoscope was introduced as a powerful tool in ear surgery over 20 years ago, endoscopic middle ear surgery or endoscopic middle ear surgery adjunct to conventional microscopic ear surgery has quickly become a widely employed surgical technique to address middle ear and mastoid pathology1,2. The main advantages of the endoscope are its panoramic and wide-angle vision. The use of the endoscope reveals the entire structure of the middle ear through the confined external auditory canal. The use of angle endoscopes (30&#176; and 45&#176;) further facilitates the exposure of the surgical field and allows dissection into the most hidden areas of the middle ear. Multiple studies have demonstrated the advantages of the superior visibility of endoscopic procedures over traditional microscopic approaches and confirmed that the major outcomes, such as the recurrence of the lesion and the changes in hearing levels, were not different between the two approaches3,4. The advances in technology and surgical instruments are still pushing the boundaries of endoscopic middle ear surgery to manage more disorders of the middle ear and even of the lateral skull base.
However, during transcanal endoscopic ear surgery, as one hand needs to hold the endoscope firmly, all surgical procedures must be performed by the other hand. As a result, surgical techniques of endoscopic ear surgery require some effort, especially the bone drilling technique poses a great technical challenge in endoscopic middle ear surgery. Due to the lack of an efficient endoscopic bone drill technique, some surgeons consider any pathology extending beyond an imaginary line, which bisects the lateral semicircular canal, not to be suitable for an exclusive endoscopic approach. Moreover, when drilling is required, some surgeons would instead switch to a microscope to enable the use of both hands, which may require additional postauricular or endaural incisions to improve access. 
To address this problem, a constant-suction bone-drilling technique has been developed in these authors' department for endaural exclusive endoscopic atticoantrotomy (retrograde mastoidectomy). From April 2020 to August 2020, 11 cases of endaural exclusive endoscopic atticoantrotomy have been successfully performed with this technique in the department. The purpose of this video is to describe the detailed procedure of this constant-suction bone-drilling technique and endaural exclusive endoscopic atticoantrotomy using this technique.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Bipolar electrocoagulation</td>
			<td>Hutong</td>
			<td>GD350-B</td>
			<td></td>
		</tr>
		<tr>
			<td>Curved dissecting scissors</td>
			<td>Jinzhong</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable infusion set and venous infusion needle</td>
			<td>KDL</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Endoscopes: 3 mm diameter, 15 cm length, 0&#176; and 45&#176;</td>
			<td>Karl Storz</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>BASCH&#160;Micromotor/PM 1600207-001 Handpiece</td>
			<td>Bienair</td>
			<td></td>
			<td>High-speed electrodrill</td>
		</tr>
		<tr>
			<td>No 11 bland and its handle</td>
			<td>Jinzhong</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Otological microsurgical instruments</td>
			<td>Tiansong</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Self-retaining retractor</td>
			<td>Tiansong</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Toothed forceps</td>
			<td>Jinzhong</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Video Equipment (HD screen; CCD camera; Xenon light source)</td>
			<td>Karl Storz</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

endaural endoscopic atticoantrotomy (retrograde mastoidectomy) using a constant suction bone-drilling technique

Endoscopic middle ear surgery is a widely employed minimally invasive surgical technique to address middle ear and mastoid pathology. Bone drilling is the main technical challenge of endoscopic middle ear surgery. The accompanying video describes the detailed protocol of a constant-suction bone-drilling technique and the procedure of endaural exclusive endoscopic atticoantrotomy (retrograde mastoidectomy) using this technique. The main components of this bone-drilling technique include a soft and flexible suction tube, which is placed into the tympanic cavity to provide constant suction, and a soft sleeve, which is wrapped around the drill shaft to prevent the high-speed rotating shaft from damaging the lens of the endoscope. With these simple modifications, the traditional otological electrodrill can be used for drilling a tiny endaural incision in endoscopic middle ear surgery. Based on this bone-drilling technique, endaural endoscopic atticoantrotomy (retrograde mastoidectomy) can be successfully established for the removal of various amounts of bone, depending on the extent of the lesion. The short-term postoperative outcome seems promising.

From April 2020 to August 2020, the senior surgeon performed endaural exclusive endoscopic atticoantrotomy on 11 patients using the above-mentioned constant-suction bone-drilling technique. The patients&#39; characteristics are described in Table 1. There were 10 men (90.9%) and 1 woman (9.1%). The patients&#39; age ranged from 9 to 63 years, with a mean age of 41 years. Most of these cases were cholesteatoma (8 cases), followed by chronic suppurative otitis media (3 cases). Of the 8 patients with cholesteatoma, the most common sites of involvement were attic (n=8, 100 %), followed by antrum (n=7, 87.5%) and tympanic cavity (n=3, 37.5%).
Intraoperative ossicular chain reconstruction was performed in 8 cases (72.7%) using methods including titanium partial ossicular replacement prostheses (4 cases) and titanium total ossicular replacement prostheses (4 cases). The results of short-term follow-up seem promising. Until the revisit at 3 months after the surgery, no sign of recurrence was noticed by clinical examination. However, the results of long-term follow-up are still unclear, which indicates further investigation is still needed.
With respect to the hearing outcome, a better postoperative air-bone gap (ABG) was observed in 5 patients, no significant change was observed in ABG in 5 patients, and a worse postoperative ABG was noted in 1 patient. The postoperative facial nerve function was normal in all the patients. No other complications were noticed postoperatively. The photographs of typical cases are shown in Figure 2.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/62450/62450fig01.jpg" /> 
Figure 1: Tailoring of a disposable infusion set and venous infusion needle and modification of electrodrill handpiece. (A) The disposable infusion set and venous infusion needle before tailoring. (B) The components cut out of the disposable infusion set and venous infusion needle: (a) electrodrill shaft sleeve, which is fixed on the handpiece with a sterile transparent sticker, (b) the soft suction tube, which will be inserted into the tympanic cavity, (c) side holes on the suction tube. <a href="https://www.jove.com/files/ftp_upload/62450/62450fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/62450/62450fig02.jpg" /> 
Figure 2: Typical cases. (A) Axial CT image of one patient shows cholesteatoma (arrowhead) in the attic and antrum. Note that the extent of the lesion goes beyond the imaginary line that bisects the lateral semicircular canal. (B) Establishment of constant-suction bone-drilling technique. Arrow indicates the soft suction tube; arrowhead indicates the electrodrill shaft sleeve. (C) The operative cavity of the same patient in (A) after completion of the endaural endoscopic atticoantrotomy. (D) Preoperative endoscopic image of the tympanic membrane. (E) Endoscopic image of the tympanic membrane of the same patient in (D) at 6 months after the operation. (F) One month after the surgery, the endaural incision (indicated by the arrowhead) is almost invisible. Abbreviations: CT = computed tomography; et = eustachian tube; hs = head of stape; ct = chorda tympani; fn = facial nerve; lsc = lateral semicircular canal. <a href="https://www.jove.com/files/ftp_upload/62450/62450fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>No</td>
			<td>Sex</td>
			<td>age</td>
			<td>side</td>
			<td colspan="2">lesion</td>
			<td colspan="2">extent</td>
			<td colspan="2">Ossicular chain reconstruction</td>
			<td colspan="2">ABG preoperative</td>
			<td>ABG 3 months later</td>
		</tr>
		<tr>
			<td>1</td>
			<td>M</td>
			<td>33</td>
			<td>R</td>
			<td colspan="2">cholesteatoma</td>
			<td colspan="2">tympanic cavity,attic,antrum</td>
			<td colspan="2">TORP</td>
			<td colspan="2">34</td>
			<td>20</td>
		</tr>
		<tr>
			<td>2</td>
			<td>M</td>
			<td>47</td>
			<td>L</td>
			<td colspan="2">cholesteatoma</td>
			<td colspan="2">attic,antrum</td>
			<td colspan="2">TORP</td>
			<td colspan="2">32</td>
			<td>22</td>
		</tr>
		<tr>
			<td>3</td>
			<td>M</td>
			<td>28</td>
			<td>L</td>
			<td colspan="2">cholesteatoma</td>
			<td colspan="2">tympanic cavity,attic,antrum</td>
			<td colspan="2">TORP</td>
			<td colspan="2">38</td>
			<td>43</td>
		</tr>
		<tr>
			<td>4</td>
			<td>M</td>
			<td>59</td>
			<td>L</td>
			<td colspan="2">cholesteatoma</td>
			<td colspan="2">tympanic cavity,attic,antrum</td>
			<td colspan="2">PORP</td>
			<td colspan="2">27</td>
			<td>22</td>
		</tr>
		<tr>
			<td>5</td>
			<td>M</td>
			<td>62</td>
			<td>R</td>
			<td colspan="2">CSOM</td>
			<td colspan="2">tympanic cavity,attic,antrum</td>
			<td colspan="2">not reconstructed</td>
			<td colspan="2">profound deafness</td>
			<td>profound deafness</td>
		</tr>
		<tr>
			<td>6</td>
			<td>F</td>
			<td>53</td>
			<td>L</td>
			<td colspan="2">CSOM</td>
			<td colspan="2">tympanic cavity,attic,antrum</td>
			<td colspan="2">not reconstructed</td>
			<td colspan="2">25</td>
			<td>15</td>
		</tr>
		<tr>
			<td>7</td>
			<td>M</td>
			<td>33</td>
			<td>L</td>
			<td colspan="2">cholesteatoma</td>
			<td colspan="2">attic,antrum</td>
			<td colspan="2">PORP</td>
			<td colspan="2">43</td>
			<td>23</td>
		</tr>
		<tr>
			<td>8</td>
			<td>M</td>
			<td>9</td>
			<td>L</td>
			<td colspan="2">cholesteatoma</td>
			<td colspan="2">attic,antrum</td>
			<td colspan="2">PORP</td>
			<td colspan="2">20</td>
			<td>21</td>
		</tr>
		<tr>
			<td>9</td>
			<td>M</td>
			<td>41</td>
			<td>L</td>
			<td colspan="2">cholesteatoma</td>
			<td colspan="2">attic</td>
			<td colspan="2">TORP</td>
			<td colspan="2">10</td>
			<td>34</td>
		</tr>
		<tr>
			<td>10</td>
			<td>M</td>
			<td>28</td>
			<td>L</td>
			<td colspan="2">cholesteatoma</td>
			<td colspan="2">attic,antrum</td>
			<td colspan="2">not reconstructed</td>
			<td colspan="2">10</td>
			<td>13</td>
		</tr>
		<tr>
			<td>11</td>
			<td>M</td>
			<td>63</td>
			<td>R</td>
			<td colspan="2">CSOM</td>
			<td colspan="2">tympanic cavity,attic,antrum</td>
			<td colspan="2">PORP</td>
			<td colspan="2">45</td>
			<td>23</td>
		</tr>
	</tbody>
</table>
Table 1: Characteristics and short-term outcomes of patients who underwent endaural endoscopic atticoantrotomy with the constant-suction bone-drilling technique. Abbreviations: M = male; F = female; R = right; L = left; CSOM = chronic suppurative otitis media; TORP = total ossicular replacement prostheses; PORP = partial ossicular replacement prostheses; ABG = air bone gap.

Watch this Scientific Journal Video about Endaural Endoscopic Atticoantrotomy Retrograde Mastoidectomy using a Constant Suction Bone-drilling Technique at JoVE.com

Endaural Endoscopic Atticoantrotomy Retrograde Mastoidectomy using a Constant Suction Bone-drilling Technique

In this paper, we present the protocol and short-term outcomes of endaural exclusive endoscopic atticoantrotomy using a constant suction bone-drilling technique.

Endaural Endoscopic Atticoantrotomy (Retrograde Mastoidectomy) using a Constant Suction Bone-drilling Technique

Endoscopic middle ear surgery is a widely employed minimally invasive surgical technique to address middle ear and mastoid pathology. Bone drilling is the ...

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3.6K Views.  Fudan University. In this paper, we present the protocol and short-term outcomes of endaural exclusive endoscopic atticoantrotomy using a constant suction bone-drilling technique.

Video: Endaural Endoscopic Atticoantrotomy Retrograde Mastoidectomy using a Constant Suction Bone-drilling Technique

Murine Cervical Heart Transplantation Model Using a Modified Cuff Technique

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are available to perform mechanistic in vivo studies. While heart transplantation models using a suture technique were first successfully developed in rats, the translation into an equally widespread used murine equivalent was never achieved due the technical complexity of the microsurgical procedure. In contrast, non-suture cuff techniques, also developed initially in rats, were successfully adapted for use in mice1-3. This technique for revascularization involves two major steps I) everting the recipient vessel over a polyethylene cuff; II) pulling the donor vessel over the formerly everted recipient vessel and holding it in place with a circumferential tie. This ensures a continuity of the endothelial layer, short operating time and very high patency rates4.
Using this technique for vascular anastomosis we performed more than 1,000 cervical heart transplants with an overall success rate of 95%. For arterial inflow the common carotid artery and the proximal aortic arch were anastomosed resulting in a retrograde perfusion of the transplanted heart. For venous drainage the pulmonary artery of the graft was anastomosed with the external jugular vein of the recipient5.
Herein, we provide additional details of this technique to supplement the video.

The murine cervical heart transplantation model is well suited for immunological as well as ischemia reperfusion injury studies. We modified the procedure using a non-suture cuff technique and performed more than 1,000 successful transplants with this approach.
Herein, we provide additional details of this technique to supplement the video.

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are ...

Human Skeletal Muscle Biopsy Procedures Using the Modified Bergstr&#246;m Technique

The percutaneous biopsy technique enables researchers and clinicians to collect skeletal muscle tissue samples. The technique is safe and highly effective. This video describes the percutaneous biopsy technique using a modified Bergstr&#246;m needle to obtain skeletal muscle tissue samples from the vastus lateralis of human subjects. The Bergstr&#246;m needle consists of an outer cannula with a small opening (&#8216;window&#8217;) at the side of the tip and an inner trocar with a cutting blade at the distal end. Under local anesthesia and aseptic conditions, the needle is advanced into the skeletal muscle through an incision in the skin, subcutaneous tissue, and fascia. Next, suction is applied to the inner trocar, the outer trocar is pulled back, skeletal muscle tissue is drawn into the window of the outer cannula by the suction, and the inner trocar is rapidly closed, thus cutting or clipping the skeletal muscle tissue sample. The needle is rotated 90&#176;&#160;and another cut is made. This process may be repeated three more times. This multiple cutting technique typically produces a sample of 100-200 mg or more in healthy subjects and can be done immediately before, during, and after a bout of exercise or other intervention. Following post-biopsy dressing of the incision site, subjects typically resume their activities of daily living right away and can fully participate in vigorous physical activity within 48-72 hr. Subjects should avoid heavy resistance exercise for 48 hr to reduce the risk of herniation of the muscle through the incision in the fascia.

Human Skeletal Muscle Biopsy Procedures Using the Modified Bergstr&amp;#246;m Technique

The purpose of this video is to present the modified Bergstr&#246;m skeletal muscle biopsy technique on human subjects.

The percutaneous biopsy technique enables researchers and clinicians to collect skeletal muscle tissue samples. The technique is safe and highly ...

Circumscribed Capsular Infarct Modeling Using a Photothrombotic Technique

Recent increase in the prevalence rate of white matter stroke demands specific research in the field. However, the lack of a pertinent animal model for white matter stroke has hampered research investigations. Here, we describe a novel method for creating a circumscribed capsular infarct that minimizes damage to neighboring gray matter structures. We used pre-surgery neural tracing with adeno-associated virus-green fluorescent protein (AAV-GFP) to identify somatotopic organization of the forelimb area within the internal capsule. The adjustment of light intensity based on different optical properties of gray and white matter contributes to selective destruction of white matter with relative preservation of gray matter. Accurate positioning of optical-neural interface enables destruction of entire forelimb area in the internal capsule, which leads to a marked and persistent motor deficit. Thus, this technique produces highly replicable capsular infarct lesions with a persistent motor deficit. The model will be helpful not only to study white matter stroke (WMS) at the behavioral, circuit, and cellular levels, but also to assess its usefulness for development of new therapeutic and rehabilitative interventions.

This manuscript describes a modeling technique of capsular infarct. Here we utilized a modified photothrombotic technique with low intensity of light after pre-surgery target mapping. Using this technique, we created a circumscribed capsular infarct model with persistent motor impairment.

Recent increase in the prevalence rate of white matter stroke demands specific research in the field. However, the lack of a pertinent animal model for ...

Using a Laminating Technique to Perform Confocal Microscopy of the Human Sclera

The sclera is a dense connective tissue that covers and protects the eye. It mainly consists of dense collagen bundles (types I, III, IV, V, VI, and VII). Due to its autofluorescence, opaqueness, and thickness, it has not been found suitable for confocal microscopy. An alternative approach to the one presented here, which uses formalin-fixed sclera embedded in paraffin for immunohistochemistry, has technical challenges, especially when preheating the tissue for antigen retrieval. Since the sclera is relatively poor in both cells and vessels, the use of larger tissue samples was explored to help prevent overlooking cells and to understand their localization in relation to vessels and other anatomical sites. To allow for the analysis of larger tissue samples under the confocal microscope, a laminating technique was performed to create thin layers from the sclera. Following the analysis of results of CD31 blood vessels and lymphatic vessel endothelial hyaluronan receptor 1 (LYVE1) positive cells, for which approval for scientific examination was obtained, the advantages and limitations of this method are discussed.

Human sclera tissue is mainly collagen; therefore, it is not easily usable for immunohistochemistry. To achieve the goal of performing immunohistochemistry for confocal microscopy of scleral tissue, a laminating technique was used.


The sclera is a dense connective tissue that covers and protects the eye. It mainly consists of dense collagen bundles (types I, III, IV, V, VI, and ...

Mouse Model for Pancreas Transplantation Using a Modified Cuff Technique

Mouse models have several advantages in transplantation research, including easy handling, a variety of genetically well-defined strains, and the availability of the widest range of molecular probes and reagents to perform in vivo as well as in vitro studies. Based on our experience with various murine transplantation models, we developed a heterotopic pancreas transplantation model in mice with the intent to analyze mechanisms underlying severe ischemia reperfusion injury-associated early graft damage. In contrast to previously described techniques using suture techniques, herein we describe a new procedure using a non-suture cuff technique. 
In recent years, we have performed more than 300 pancreas transplantations in mice with an overall success rate of &gt;90%, a success rate never described before in mouse pancreas transplantation. The backbone of this non-suture cuff technique for graft revascularization consists of two major steps: (I) pulling the recipient vessel over a polyethylene/polyamide cuff and fixing it with a circumferential ligature, and (II) placing the donor vessel over the everted recipient vessel and fixing it with a second circumferential ligature. The resultant continuity of the endothelial layer results in less thrombogenic lesions with high patency rates and, finally, high success rates.
In this model, arterial anastomosis is achieved by pulling the abdominal aorta of the donor graft over the everted common carotid artery of the recipient animal. Venous drainage of the graft is achieved by pulling the portal vein of the graft over the everted external jugular vein of the recipient. This manuscript provides details and crucial steps of the organ recovery and organ implantation procedures, which will allow researchers with microsurgical skills to perform the transplantation successfully in their laboratories.

Among abdominal solid organ transplantation, pancreatic grafts are prone to develop severe ischemia reperfusion injury-associated graft damage, leading eventually to early graft loss. This protocol describes a model of murine pancreas transplantation using a non-suture cuff technique, ideally suited for analyzing these early, deleterious damages.

Mouse models have several advantages in transplantation research, including easy handling, a variety of genetically well-defined strains, and the ...

Topical Airway Anesthesia for Awake-endoscopic Intubation Using the Spray-as-you-go Technique with High Oxygen Flow

A patient&#39;s willingness to cooperate is an absolute precondition for successful awake intubation of the trachea. Whilst drug-sedation of patients can jeopardize their spontaneous breathing, topical anesthesia of the airway is a popular technique. The spray-as-you-go technique represents one of the simplest opportunities to anesthetize the airway mucosa. The application of local anesthetic through the working channel of the flexible endoscope is a widespread practice for anesthetists as well as pulmonologists. There is neither need for additional devices nor special training as a pre-requisite to perform this technique. However, a known clinical problem is the coughing and gagging reflex that may occur when the liquid anesthetic strikes the airway mucosa and other sensitive structures like the vocal cords. This can be avoided by the use of oxygen applied through the working channel with the aim of fogging the local anesthetic into finer particles. Furthermore, the oxygen flow provides a higher oxygen supply and contributes to a better view, dispersing mucus secretions and blood away from the lens. Using an atomizer with a high oxygen flow of 10 L/min we maximized these benefits, caused less coughing and had more satisfied and therefore cooperative patients. Possible, but very rare complications of using oxygen flow including gastric insufflation, organ rupture or barotrauma did not arise. We attribute the complication-free use of high oxygen flow to the design of the set, which permits flow and pressure release.

The topical anesthetic lidocaine was atomized using a high oxygen flow through the working channel of a flexible intubating endoscope to achieve topical airway anesthesia for awake endotracheal intubation. We prefer this modified spray-as-you-go technique for endoscopic intubation to classical bolus application because of higher patient satisfaction and better compliance.

A patient&#39;s willingness to cooperate is an absolute precondition for successful awake intubation of the trachea. Whilst drug-sedation of patients can ...

Establishment of a Mouse Severe Acute Pancreatitis Model using Retrograde Injection of Sodium Taurocholate into the Biliopancreatic Duct

The prevalence of acute pancreatitis (AP), especially severe acute pancreatitis (SAP), is increasing in younger age groups annually. However, there is a lack of effective treatments in the current clinical practice. With the easy accessibility of transgenic and knockout strains and their small size, which allows minimal doses of drugs required for in vivo evaluation, a well-established experimental model in mice is preferred for AP research. Moreover, SAP induced through sodium taurocholate (TC) is currently one of the most widely used and best characterized models. This model has been investigated for novel therapies and possible molecular events during the process of AP. Here, we present the generation of an AP mouse model using sodium taurocholate and a simple homemade microsyringe. Moreover, we also provide the methodology for the subsequent histology and serological testing.

A mouse model of severe acute pancreatitis is described herein. The procedure presented here is very rapid, simple, and accessible, thereby potentially allowing the study of the molecular mechanisms and different therapeutic interventions in acute pancreatitis in a convenient way.

The prevalence of acute pancreatitis (AP), especially severe acute pancreatitis (SAP), is increasing in younger age groups annually. However, there is a ...

Endoscopic Cholesteatoma Surgery

Implementation of endoscopes in cholesteatoma surgery resulted in considerable changes in the management of cholesteatoma in the last two decades. Compared to the microscopic approach with an excellent but straight-line view and limited illumination, the introduction of endoscopes provides a wide-angled panoramic view. Moreover, angled lenses allow the surgeon to visualize the middle ear and its hidden recesses through a transcanal, minimally-invasive approach. The endoscope enables the surgeon to remove limited cholesteatoma of the middle ear and its recesses using an exclusive endoscopic technique by taking advantage of these benefits. This reduces the rate of residual disease and sparing external incisions and excessive temporal bone drilling as in a transmastoid approach. Since transcanal endoscopic access is mainly a one-handed technique, it implies the need for specific procedures and technical refinements. This article describes a step-by-step guide as a surgical manual for endoscopic removal of epitympanic cholesteatoma. Different techniques for cholesteatoma dissection and bone removal for epitympanectomy, including curettage and powered instruments such as drills and ultrasonic devices with their outcomes, are discussed. This may offer ear surgeons insight into technical refinements and the latest technological developments and open the horizon for different techniques.

The present protocol describes a step-by-step guide for the complete endoscopic removal of epitympanic cholesteatoma with different techniques for cholesteatoma dissection and bone removal for epitympanectomy.

Implementation of endoscopes in cholesteatoma surgery resulted in considerable changes in the management of cholesteatoma in the last two decades. ...

A Retrograde Implantation Approach for Peritoneal Dialysis Catheter Placement in Mice

Murine models are employed to probe various aspects of peritoneal dialysis (PD), such as peritoneal inflammation and fibrosis. These events drive peritoneal membrane failure in humans, which remains an area of intense investigation due to its profound clinical implications in managing patients with end-stage kidney disease (ESKD). Despite the clinical importance of PD and its related complications, current experimental murine models suffer from key technical challenges that compromise the models&#39; performance. These include PD catheter migration and kinking and usually warrant earlier catheter removal. These limitations also drive the need for a greater number of animals to complete a study. Addressing these drawbacks, this study introduces technical improvements and surgical nuances to prevent commonly observed PD catheter complications in a murine model. Moreover, this modified model is validated by inducing peritoneal inflammation and fibrosis using lipopolysaccharide injections. In essence, this paper describes an improved method to create an experimental model of PD.

This article describes modifications of a procedure to implant a peritoneal dialysis catheter in a murine model to avoid major technical issues observed with the conventional techniques.

Murine models are employed to probe various aspects of peritoneal dialysis (PD), such as peritoneal inflammation and fibrosis. These events drive ...

Full-Endoscopic Isolation Zone Technique for the Treatment of Lumbar Disc Herniation

Lumbar disc herniation (LDH) is a type of serious sinus or sciatic nerve dysfunction caused by nucleus pulposus protrusion and annulus fibrosus tears. Its clinical symptoms often include severe low back pain, limited lumbar movement, sciatic nerve pain in the lower limbs, and even cauda equina syndrome. The common treatment for LDH is a conservative treatment scheme involving medicine, rest, and physical therapy. However, if the conservative treatment scheme is ineffective, a surgical treatment approach is adopted. Traditional open lumbar surgery has some disadvantages, including the potential for severe surgical trauma, severe blood loss during the operation, instability of the lumbar spine, and loss of the lumbar motor unit. Among the minimally invasive surgical schemes, full-endoscopic spine surgery (FESS) is undoubtedly the most appropriate and has the advantages of minimal trauma, high safety, quick postoperative recovery, and the retention of the stable structure and the motor unit of the lumbar spine. However, simultaneously, incomplete removal of the nucleus pulposus and residual nerve dysfunction after surgery can occur. To avoid these shortcomings, we studied a specific spinal endoscopy technique, the "isolation zone" surgical strategy, which can effectively block the pain from the nerve conduction pathway by completely relieving the nerve compression and nerve dysfunction through the orderly treatment of the protruding nucleus pulposus, the fissure of the annulus fibrosus, the sinus nerve, and the surrounding inflammatory soft tissues.

Here, we present a protocol for the &#34;isolation zone&#34; technique in the treatment of lumbar disc herniation (LDH) under full-endoscopic spine surgery (FESS), including intervertebral foramen formation, targeted catheterization, nucleus pulposus resection, and annulus fibrosus formation, which together completely block the pain from the nerve conduction pathway.

Lumbar disc herniation (LDH) is a type of serious sinus or sciatic nerve dysfunction caused by nucleus pulposus protrusion and annulus fibrosus tears. Its ...