Approval or consent to perform this study was not required since the use of patients&#39; data is not applicable.
1. Planning procedure
<ol>
	<li>Open the planning software and reinsure that the newest version is installed.</li>
	<li>Click on EXPERT to switch the Work mode from EASY to EXPERT.</li>
	<li>Click on NEW on the right sidebar to start a new case planning.</li>
	<li>Choose the Image Source by selecting the folder with the pre-operative DICOM CBCT data. 
	NOTE: Adjustment of the Hounsfield Units (HU) threshold may be necessary depending on the image quality displayed in the window on the lower left).</li>
	<li>Select Create Dataset to continue with the planning.</li>
	<li>Choose the type of planning (Maxilla or Mandibula).</li>
	<li>Select Edit Segmentations to start segmentation of the dental arch.</li>
	<li>Switch to axial view on the left sidebar.</li>
	<li>Select Density Measurement to perform this measurement for the higher radiopaque tooth structure and the surrounding less radiopaque states (e.g., air). Average the values (Figure 1). 
	NOTE: The average value is calculated manually; the software does not offer a function for this purpose.</li>
	<li>Return to 3D Reconstruction on the left sidebar.</li>
	<li>Adjust the lower threshold to the calculated average value (Figure 2A).</li>
	<li>Segment by using the Flood Fill tool. Give a name to the segmentation (Figure 2B). 
	NOTE: When the Flood Fill tool is selected and active, segmentation is possible with a left-click on the desired area in the 3D Reconstruction view.</li>
	<li>Finish segmentation of the dental arch by selecting Close Module.</li>
	<li>Left-click on Object &#62; Add &#62; Model Scan.</li>
	<li>Select Load model scan. 
	NOTE: A digital surface scan utilizing a suitable intraoral scanner must be created in advance and the data set must be available on the PC as an stl file.</li>
	<li>Select Align to Other Object.</li>
	<li>Select the segmentation created in step 1.13 (Figure 2C).</li>
	<li>Select three different matching points in the Registration Object and Model Scan respectively or landmark registration by left-clicking on the desired area. 
	NOTE: Try to spatially distribute the points to enhance the semi-automatic matching of the data. Choosing anatomically prominent regions (cusp tips, marginal ridges) as landmarks will also facilitate the semi-automatic registration process).</li>
	<li>Check registration in all the planes by manually scrolling through the planes and finish the registration. 
	NOTE: Manual corrections may be necessary if deviations between CBCT and surface scan are evident (Figure 3).</li>
	<li>Plan access cavity by adding an Implant. 
	NOTE: The utilized endodontic bur must be added to the implant database beforehand via Extras &#62; Implant Designer &#62; Implant &#62; Import Database. The bur can be imported as a .cdxBackup file as described in the software manufacturer&#39;s instructions.</li>
	<li>Place the bur to the targeted position and check in all the planes by left-clicking and moving (the software provides different planes and views for adequate positioning) (Figure 4A). 
	NOTE: The bur&#39;s long axis should be centered in the visualized root canal space. A cylindric diamond bur with a diameter of 1.0 mm can be used for most access cavity preparations. However, in teeth with narrow roots, a smaller diameter should be considered to provide minimally invasive access to the root canal orifice.</li>
	<li>Select Object &#62; Add &#62; 3D Model to add the STL File of the marker-tray.</li>
	<li>Place the tray close to the planned access cavity preparation, make sure there will be no interference during the actual procedure (Figure 4B).</li>
	<li>Add a Surgical Guide and design the marker tray according to the DNS manufacturer&#39;s instruction guide.</li>
	<li>Export the marker tray as an STL file and manufacture it with a 3D-Printer (Figure 4C).</li>
	<li>Export the entire planning by selecting Object &#62; Virtual Planning Export &#62; Generic Planning Objects Container format according to the DNS manufacturer&#39;s instruction guide.</li>
</ol>
2. Access cavity preparation
<ol>
	<li>Import the planning data to the DNS via the USB.</li>
	<li>Select the case that is being treated.</li>
	<li>Insert the marker into the 3D-printed marker tray.</li>
	<li>Check the fit of the marker in the marker tray.</li>
	<li>Check the fit of the marker tray on the dental arch (Figure 4D).</li>
	<li>Insert the bur into the handpiece that was used for the planning.</li>
	<li>Register the bur in the bur registration tool according to the DNS manufacturer&#39;s instruction (Figure 5A).</li>
	<li>Check the correct registration by moving the bur to a prominent location (e.g., incisal edge); the DNS should show the tip of the instrument at the exact same position (Figure 5B). 
	NOTE: If an incorrect bur position is displayed, check the proper fit of the tray on the dentition and the proper fit of the marker in the tray. If necessary, repeat the bur registration. If an incorrect position is still displayed, material distortion might have occurred in the tray fabricating process, and access cavity preparation should not be performed.</li>
	<li>Move the bur to the tooth that will be treated. 
	NOTE: The DNS will automatically switch to a different view, providing real-time information about the spatial and angular deviation; a depth orientation is also provided on the right side (Figure 5C).</li>
	<li>Perform the access cavity preparation with DNS guidance. 
	&#8203;NOTE: Preparation should be performed intermittently. Debris should be removed from the bur and the access cavity to avoid heat development during preparation.</li>
</ol>
3. Treatment evaluation
<ol>
	<li>Generate post-operative CBCT imaging with the same CBCT machine settings as done pre-operatively.</li>
	<li>Open pre-operative planning in the software.</li>
	<li>Select Edit Segmentations.</li>
	<li>Adjust the lower threshold to the calculated average value (see step 1.11).</li>
	<li>Segment the treated tooth by using the Flood Fill tool and give a name to the segmentation. 
	NOTE: If the tooth has proximal contact, one may have to draw manual segmentation boundaries, Figure 6.</li>
	<li>Finish segmentation by selecting the Close Module option.</li>
	<li>Right-click on the overview column on the left on the segmented tooth and select Convert Into 3D Model. 
	NOTE: The segmentation will appear as a 3D Model in the overview.</li>
	<li>Right-click on the 3D Model of the segmented pre-operative tooth, and then click on Visualization &#62; Properties. The volume of the tooth will be displayed in mm&#179;.</li>
	<li>Open a new case.</li>
	<li>Import DICOM Image Data of the post-operative CBCT scan (settings for CBCT imaging should be the same as pre-operative).</li>
	<li>Select Edit Segmentations.</li>
	<li>Adjust the lower threshold to the same value that was calculated for the pre-operative data.</li>
	<li>Segment the treated tooth by using the Flood Fill tool and give a name to the segmentation. 
	NOTE: If the tooth has proximal contact, one may have to draw manual segmentation boundaries.</li>
	<li>Finish segmentation by selecting the Close Module option.</li>
	<li>Right-click on the segmented tooth, convert it into 3D Model. 
	NOTE: The segmentation will appear as a 3D Model in the overview.</li>
	<li>Right-click on the 3D Model of the segmented pre-operative tooth, and then click on Visualization &#62; Properties. The volume of the tooth will be displayed in mm3. 
	NOTE: The difference between the pre- and the post-operative volume is the volume of substance loss during the access cavity preparation.</li>
	<li>Open the pre-operative planning.</li>
	<li>Import a Model Scan &#62; Import Segmentation and choose the post-operative tooth segmentation.</li>
	<li>Align with pre-operative tooth segmentation using landmark registration (see step 1.18). 
	NOTE: The matching procedure of the pre- and post-operative data is beneficial for visualization but not mandatory for volumetric measurements.</li>
</ol>

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M., Jeon, J., Koak, J. -. Y., Kim, S. -. K., Heo, S. -. 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All the authors declare that they have no conflicts of interest.

Several studies and case reports have demonstrated the feasibility of guided access cavity preparation in endodontics7. Navigation utilizing templates and sleeves for bur guidance (static navigation) was described to be a precise and safe method to access calcified root canals. Besides, the method was found to be independent from the operator&#39;s degree of clinical experience16, offering the possibility to treat teeth with advanced PCC without the risks of large loss of tooth structure or iatrogenic errors such as perforations.
When root canal treatment of posterior teeth with advanced PCC is indicated, static navigation utilizing templates and burs might become challenging due to the reduced interocclusal space, especially in patients with a reduced mouth opening7. A recent investigation revealed that deviations between planned and performed access cavities were significantly higher in molars compared to premolars or anterior teeth17, which was presumed to be attributed to interferences of the handpiece&#39;s head and the opposite teeth. A sleeveless template-based approach was described in a recent case report as an alternative to the mostly used sleeve-containing system and showed satisfying results18.
DNS provide real-time information about the spatial and angular deviation between the planned and the actual position of the bur that is used for access cavity preparation and thus there is no need for a template and its potentially reduced practicability in situations with reduced interocclusal space. Hence, DNS provide interoperative flexibility since the direction of access cavity preparation can be adjusted, which is not the case when a static navigation (template-based) approach is used.
Generally, the use of Guided Endodontics should be limited to teeth with advanced calcification, in which a conventional access cavity preparation is fraught with risk of iatrogenic errors, including root perforation and thus threatening tooth preservation, since the use of ionizing radiation (CBCT) is required for 3D planning. The use of CBCT in Endodontics should follow current scientific recommendations19. When generating the CBCT imaging data, a configuration with a limited field of view (FOV) will reduce the radiation dose. Visualization of highly calcified root canals can be enabled by a reduced voxel size, which allows accurate virtual 3D planning.
Also, the costs to perform a guided access cavity preparation are higher compared to the conventional technique. Until now, only a few DNS are available on the market, resulting in high acquisition fees. Nevertheless, static guided navigation also implies additional costs (template manufacturing process, sleeves, burs).
The results presented in the literature for the accuracy of DNS in non-surgical endodontic treatment are very promising. However, the few available systems consist of bulky and extraoral markers, which can reduce patient and operator comfort during the procedure. Here, the utilized DNS uses miniaturized components to avoid these disadvantages. Several studies in oral implantology20,21,22,23 and one investigation for endodontic access cavity preparation8 demonstrated the feasibility of this certain DNS and that it might become a potential alternative to template-based static navigation.
Sources for inaccuracies when using a DNS might potentially arise from planning errors. For example, full arch surface scans are still challenging24,25 for intraoral scanners and thus local deviations in the surface scan can occur and impair the precision of matching with the CBCT data.
For dynamic navigation also, the quality and fit of the marker tray is critical. Depending on the manufacturing process, material distortion26 might lead to deviations between the actual position and the displayed position of the bur. Geometrically considered, the deviation increases in case of a distortion when the angle between the camera and the marker is rather obtuse. Therefore, in the planning process for this specific DNS, it should be considered to place the marker tray in a position that provides a rather right angle between the camera and the marker surface. Nonetheless, in an in vitro study, there were no significant differences found between different types of marker positioning (contralateral/ipsilateral)23.
When performing volumetric measurements of pre- and post-operative conditions to determine the loss of tooth structure, it is crucial to use the same CBCT parameters and to set the same HU thresholds27. When a manual drawing of segmentation boundaries is necessary (in cases with proximal contacts) to perform a single tooth segmentation, inaccuracies might occur since the boundaries are drawn subjectively. More complex segmentation operations have been described in the literature to automatize the segmentation processes of teeth that have proximal contacts28,29. Nevertheless, inaccuracies due to manual segmentation boundaries in cases with proximal contacts are negligible in relation to the volume of substance loss.

In non-surgical endodontic treatment, the preparation of an adequate access cavity is the first invasive step1. Teeth that have undergone pulp canal calcification (PCC) are difficult and time-consuming to treat2, leading to more iatrogenic errors such as perforations that may be crucial for the prognosis of the tooth3. PCC is a process that can be observed after dental trauma4,5 and as a response to stimuli such as caries, restorative procedures, or vital pulp therapy6, leading to a relocation of the root canal orifice toward the apex. In general, PCC is a sign of vital pulp, and treatment is only indicated when clinical and/or radiographic signs of a pulpal or apical pathology become apparent. The more apical the orifice of the remaining root canal space is located, spatial orientation and illumination become more difficult, even for a specialist in endodontics and with additional devices, e.g., operating microscopes.
Besides static navigation7, which is a template-based approach that leads a bur to the target point, dynamic navigation systems (DNS) were described to be also suitable for the preparation of endodontic access cavities8,9,10,11,12,13,14,15. DNS consists of a camera-marker-computer system, in which a rotating instrument (e.g., diamond bur) is recognized, and its position in the patient&#39;s mouth is visualized in real-time, thus providing guidance to the operator. The few commercially available systems are equipped with relatively large extraoral marker systems and large camera devices. Recently a miniaturized system, consisting of a low weight camera (97 g) and a small intraoral marker (10 mm x 15 mm), was described for endodontic access cavity preparation8. This work aims to present the technique of guided access cavity preparation by means of this miniaturized dynamic navigation system from imaging to clinical implementation. For research purposes, a treatment evaluation (determination of substance loss due to access cavity preparation) is possible after post-operative CBCT and is also presented in this article.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Accuitomo 170</td>
			<td>Morita Manufacturing</td>
			<td>NA</td>
			<td>CBCT machine</td>
		</tr>
		<tr>
			<td>coDiagnostiX</td>
			<td>Dental Wings Inc</td>
			<td>Version 10.4</td>
			<td>Planning software, which is mainly intended for implant surgery. Endodontic access cavities can be planned by adding the utlized bur to the implant database</td>
		</tr>
		<tr>
			<td>DENACAM</td>
			<td>mininavident</td>
			<td>NA</td>
			<td>Dynamic Nagivation System, consisting of (1) camera, which is mounted to an electric handpiece, (2) marker, (3)computer and screen, (4) associated software</td>
		</tr>
		<tr>
			<td>TRIOS 3</td>
			<td>3Shape A/S</td>
			<td>NA</td>
			<td>Surface scanner</td>
		</tr>
	</tbody>
</table>

dynamic navigation in endodontics: guided access cavity preparation by means of a miniaturized navigation system

In the case of teeth with pulp canal calcification (PCC) and apical pathology or pulpitis, root canal treatment can be very challenging. PCC are common sequelae of dental trauma but can also occur with stimuli such as caries, bruxism, or after placing a restoration. In order to access the root canal as minimally invasive as possible in case of a necessary root canal treatment, dynamic navigation has recently been introduced in endodontics in addition to static navigation. The use of a dynamic navigation system (DNS) requires pre-operative cone-beam computed tomography (CBCT) imaging and a digital surface scan. If necessary, reference markers must be placed on the teeth before the CBCT scan; with some systems, these can also be planned and created digitally afterward. By means of a stereo camera connected to the planning software, the drill can now be coordinated with the help of reference markers and virtual planning. As a result, the position of the drill can be displayed on the monitor in real-time during preparation in different planes. In addition, the spatial displacement, the angular deviation, and the depth position are also displayed separately. The few commercially available DNS mostly consist of relatively large camera-marker-systems. Here, the DNS contains miniaturized components: a low-weight camera (97 g) mounted on the micromotor of the electric handpiece utilizing a manufacturer-specific connecting mechanism and a small marker (10 mm x 15 mm), which can be easily attached to an individually manufactured intraoral tray. For research purposes, a post-operative CBCT scan can be matched with the pre-operative one, and the volume of tooth structure removed can be calculated by the software. This work aims to present the technique of guided access cavity preparation by means of a miniaturized navigation system from imaging to clinical implementation.

Figure 7A shows the occlusal view of a prepared endodontic access cavity in a model central incisor with the aid of the DNS. Figure 7B shows the associated CBCT scan in sagittal view. The post-operative segmentation is then matched with the pre-operative CBCT data (Figure 7C). Pre- and post-operative 3D models are matched (Figure 7D) and the pre- (412.12 mm3) and post-operative (405.09mm3) volume can be calculated by the planning software automatically and displayed in mm3 (Figure 8). Therefore, the volume of substance loss amounts to 7.03 mm3. The absolute value of substance loss for itself is not of major relevance. Substance loss values for different approaches (e.g., conventional access cavity preparation versus DNS or comparison of different DNS) should be compared, and significant differences in the volume of substance loss indicate which technique provides the least invasive approach.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/63687/63687fig01.jpg" /> 
Figure 1: Measure the density of the teeth and the surrounding air. Average the measured values. (Arrow: density measuring tool). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63687/63687fig01large.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/63687/63687fig02.jpg" /> 
Figure 2: 3D reconstruction and segmentation. (A) 3D Reconstruction of pre-operative CBCT data. The lower threshold is adjusted to the calculated value. (B) Segmentation has been performed with the flood fill tool. The segmentation has been named &#34;teeth&#34; (color white). (C) Choose your segmentation as a registration object. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63687/63687fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/63687/63687fig03.jpg" /> 
Figure 3: Matching of CBCT and surface scan data. Check all the planes for correct alignment and finish the registration. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63687/63687fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/63687/63687fig04.jpg" /> 
Figure 4: Access cavity planning and tray manufacturing. (A) The bur is virtually placed to the root canal orifice, providing straight-line access. (B) The marker tray is placed on the dental arch. (C) The marker tray has been designed to fit on the teeth surface. It is now ready to be exported and 3D printed. (D) The marker has been placed into the 3D-printed marker tray. Now the marker tray is placed on the dental arch and its fit is checked. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63687/63687fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/63687/63687fig05.jpg" /> 
Figure 5: Bur registration and real-time visualization by the DNS. (A) Bur registration is performed with the associated tool. (B) Correct registration is checked before the treatment begins. The bur is placed to a prominent anatomic landmark (here incisal edge). The displayed position by the DNS should be exactly the same. (C) Display view of the DNS during access cavity preparation. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63687/63687fig05large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/63687/63687fig06.jpg" /> 
Figure 6: Single tooth segmentation for volume determination. (A) 3D reconstruction of CBCT data shows that teeth are connected due to proximal contacts. Two manual segmentation boundaries are drawn to provide a single tooth segmentation. Here: frontal view. (B) Lateral view. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63687/63687fig06large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/63687/63687fig07.jpg" /> 
Figure 7: Matching of post- and pre-operative data. (A) Occlusal view of an endodontic access cavity that was performed with aid of a DNS. (B) Post-operative CBCT data in sagittal view. Note the straight-line access to the root canal space. (C) The post-operative segmentation of the tooth (red color) is matched with the pre-operative CBCT data (blue color). (D) 3D Models generated from the segmentation data are matched and show good accordance. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63687/63687fig07large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/63687/63687fig08.jpg" /> 
Figure 8: Volume calculation. (A) For the pre-operative 3D Model of the tooth, the planning software is able to calculate the volume in mm3. (B) Volume determination for the 3D Model of the tooth after access cavity preparation. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63687/63687fig08large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Dynamic Navigation in Endodontics: Guided Access Cavity Preparation by Means of a Miniaturized Navigation System at JoVE.com

Dynamic Navigation in Endodontics: Guided Access Cavity Preparation by Means of a Miniaturized Navigation System

Dynamic navigation systems (DNS) provide real-time visualization and guidance to the operator during endodontic access cavities preparation. The planning of the procedure requires three-dimensional imaging utilizing cone beam computed tomography and surface scans. After the export of the planning data to the DNS, access cavities can be prepared with minimal invasion.

In the case of teeth with pulp canal calcification (PCC) and apical pathology or pulpitis, root canal treatment can be very challenging. PCC are common ...

dynamic-navigation-endodontics-guided-access-cavity-preparation-means

Nanyang Technological University

Research

JoVE Journal

Medicine

4.2K Views.  University of Basel. Dynamic navigation systems (DNS) provide real-time visualization and guidance to the operator during endodontic access cavities preparation. The planning of the procedure requires three-dimensional imaging utilizing cone beam computed tomography and surface scans. After the export of the planning data to the DNS, access cavities can be prepared with minimal invasion.

Video: Dynamic Navigation in Endodontics: Guided Access Cavity Preparation by Means of a Miniaturized Navigation System

Remote Magnetic Navigation for Accurate, Real-time Catheter Positioning and Ablation in Cardiac Electrophysiology Procedures

New remote navigation systems have been developed to improve current limitations of conventional manually guided catheter ablation in complex cardiac substrates such as left atrial flutter. This protocol describes all the clinical and invasive interventional steps performed during a human electrophysiological study and ablation to assess the accuracy, safety and real-time navigation of the Catheter Guidance, Control and Imaging (CGCI) system. Patients who underwent ablation of a right or left atrium flutter substrate were included. Specifically, data from three left atrial flutter and two counterclockwise right atrial flutter procedures are shown in this report. One representative left atrial flutter procedure is shown in the movie. This system is based on eight coil-core electromagnets, which generate a dynamic magnetic field focused on the heart. Remote navigation by rapid changes (msec) in the magnetic field magnitude and a very flexible magnetized catheter allow real-time closed-loop integration and accurate, stable positioning and ablation of the arrhythmogenic substrate.

This report provides a detailed description of a new remote navigation system based on magnetic driven forces, which has been recently introduced as a new robotic tool for human cardiac electrophysiology procedures.

New remote navigation systems have been developed to improve current limitations of conventional manually guided catheter ablation in complex cardiac ...

Development of an Audio-based Virtual Gaming Environment to Assist with Navigation Skills in the Blind

Audio-based Environment Simulator (AbES) is virtual environment software designed to improve real world navigation skills in the blind. Using only audio based cues and set within the context of a video game metaphor, users gather relevant spatial information regarding a building's layout. This allows the user to develop an accurate spatial cognitive map of a large-scale three-dimensional space that can be manipulated for the purposes of a real indoor navigation task. After game play, participants are then assessed on their ability to navigate within the target physical building represented in the game. Preliminary results suggest that early blind users were able to acquire relevant information regarding the spatial layout of a previously unfamiliar building as indexed by their performance on a series of navigation tasks. These tasks included path finding through the virtual and physical building, as well as a series of drop off tasks. We find that the immersive and highly interactive nature of the AbES software appears to greatly engage the blind user to actively explore the virtual environment. Applications of this approach may extend to larger populations of visually impaired individuals.

Audio-based Environment Simulator (AbES) is virtual environment software designed to improve real world navigation skills in the blind.

Audio-based Environment Simulator (AbES) is virtual environment software designed to improve real world navigation skills in the blind. Using only audio ...

Povidone Iodine Rectal Preparation at Time of Prostate Needle Biopsy is a Simple and Reproducible Means to Reduce Risk of Procedural Infection

Single institution and population-based studies highlight that infectious complications following transrectal ultrasound guided prostate needle biopsy (TRUS PNB) are increasing. Such infections are largely attributable to quinolone resistant microorganisms which colonize the rectal vault and are translocated into the bloodstream during the biopsy procedure. A povidone iodine rectal preparation (PIRP) at time of biopsy is a simple, reproducible method to reduce rectal microorganism colony counts and therefore resultant infections following TRUS PNB.
All patients are administered three days of oral antibiotic therapy prior to biopsy. The PIRP technique involves initially positioning the patient in the standard manner for a TRUS PNB. Following digital rectal examination, 15 ml&#160;of a 10% solution of commercially available povidone iodine is mixed with 5 ml&#160;of 1% lidocaine jelly to create slurry. A 4 cm x 4 cm sterile gauze is soaked in this slurry and then inserted into the rectal vault for 2 min after which it is removed. Thereafter, a disposable cotton gynecologic swab is used to paint both the perianal area and the rectal vault to a distance of 3 cm from the anus. The povidone iodine solution is then allowed to dry for 2 - 3 min prior to proceeding with standard transrectal ultrasonography and subsequent biopsy.
This PIRP technique has been in practice at our institution since March of 2012 with an associated reduction of post-biopsy infections from 4.3% to 0.6% (p = 0.02). The principal advantage of this prophylaxis regimen is its simplicity and reproducibility with use of an easily available, inexpensive agent to reduce infections. Furthermore, the technique avoids exposing patients to additional systemic antibiotics with potential further propagation of multi-drug resistant organisms. Usage of PIRP at TRUS PNB, however, is not applicable for patients with iodine or shellfish allergies.

Here, we present a protocol for use at the time of transrectal ultrasound guided prostate needle biopsy (TRUS PNB) that is a simple and cost-effective means to reduce infections following the procedure.

Single institution and population-based studies highlight that infectious complications following transrectal ultrasound guided prostate needle biopsy ...

Functional Human Liver Preservation and Recovery by Means of Subnormothermic Machine Perfusion

There is currently a severe shortage of liver grafts available for transplantation. Novel organ preservation techniques are needed to expand the pool of donor livers. Machine perfusion of donor liver grafts is an alternative to traditional cold storage of livers and holds much promise as a modality to expand the donor organ pool. We have recently described the potential benefit of subnormothermic machine perfusion of human livers. Machine perfused livers showed improving function and restoration of tissue ATP levels. Additionally, machine perfusion of liver grafts at subnormothermic temperatures allows for objective assessment of the functionality and suitability of a liver for transplantation. In these ways a great many livers that were previously discarded due to their suboptimal quality can be rescued via the restorative effects of machine perfusion and utilized for transplantation. Here we describe this technique of subnormothermic machine perfusion in detail. Human liver grafts allocated for research are perfused via the hepatic artery and portal vein with an acellular oxygenated perfusate at 21 &#176;C.

We describe a method of ex vivo machine perfusion of human liver grafts at subnormothermic temperature (21 &#176;C).

There is currently a severe shortage of liver grafts available for transplantation.  Novel organ preservation techniques are needed to expand the pool of ...

Electromagnetic Navigation Transthoracic Nodule Localization for Minimally Invasive Thoracic Surgery

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or excision. Many of these nodules are identified and excised via minimally invasive thoracic surgery; however, subcentimeter and subsolid nodules are frequently difficult to identify intra-operatively. This can be mitigated by the use of electromagnetic transthoracic needle localization. This protocol delineates the step-by-step process of electromagnetic localization from the pre-operative period to the postoperative period and is an adaptation of the electromagnetically guided percutaneous biopsy previously described by Arias et al. Pre-operative steps include obtaining a same day CT followed by the generation of a three-dimensional virtual map of the lung. From this map, the target lesion(s) and an entry site are chosen. In the operating room, the virtual reconstruction of the lung is then calibrated with the patient and the electromagnetic navigation platform. The patient is then sedated, intubated, and placed in the lateral decubitus position. Using a sterile technique and visualization from multiple views, the needle is inserted into the chest wall at the prechosen skin entry site and driven down to the target lesion. Dye is then injected into the lesion and, then, continuously during needle withdrawal, creating a tract for visualization intra-operatively. This method has many potential benefits when compared to the CT-guided localization, including a decreased radiation exposure and decreased time between the dye injection and the surgery. Dye diffusion from the pathway occurs over time, thereby limiting intra-operative nodule identification. By decreasing the time to surgery, there is a decrease in wait time for the patient, and less time for dye diffusion to occur, resulting in an improvement in nodule localization. When compared to electromagnetic bronchoscopy, airway architecture is no longer a limitation as the target nodule is accessed via a transparenchymal approach. Details of this procedure are described in a step-by-step fashion.

Presented here is a protocol for lung nodule localization using dye marking via electromagnetically navigated transthoracic needle access. The technique described here can be accomplished in the peri-operative period to optimize nodule localization and to successful resection when performing minimally invasive thoracic surgery.

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or ...

Intraoperative Assessment of Resection Margins in Oral Cavity Cancer: This is the Way

The goal of head and neck oncological surgery is complete tumor resection with adequate resection margins while preserving acceptable function and appearance. For oral cavity squamous cell carcinoma (OCSCC), different studies showed that only 15%-26% of all resections are adequate. A major reason for the low number of adequate resections is the lack of information during surgery; the margin status is only available after the final histopathologic assessment, days after surgery.
The surgeons and pathologists at the Erasmus MC University Medical Center in Rotterdam started the implementation of specimen-driven intraoperative assessment of resection margins (IOARM) in 2013, which became the standard of care in 2015. This method enables the surgeon to turn an inadequate resection into an adequate resection by performing an additional resection during the initial surgery. Intraoperative assessment is supported by a relocation method procedure that allows accurate identification of inadequate margins (found on the specimen) in the wound bed.
The implementation of this protocol resulted in an improvement of adequate resections from 15%-40%. However, the specimen-driven IOARM is not widely adopted because grossing fresh tissue is counter-intuitive for pathologists. The fear exists that grossing fresh tissue will deteriorate the anatomical orientation, shape, and size of the specimen and therefore will affect the final histopathologic assessment. These possible negative effects are countered by the described protocol. Here, the protocol for specimen-driven IOARM is presented in detail, as performed at the institute.

The goal of this protocol is to provide a clear overview of specimen-driven intraoperative assessment of resection margins. It is encouraged to implement this protocol to improve patient care at other institutes.

The goal of head and neck oncological surgery is complete tumor resection with adequate resection margins while preserving acceptable function and ...

Real-Time Dynamic Navigation System for the Precise Quad-Zygomatic Implant Placement in a Patient with a Severely Atrophic Maxilla

Zygomatic implants (ZIs) are an ideal way to address cases of a severely atrophic edentulous maxilla and maxilla defects because they replace extensive bone augmentation and shorten the treatment cycle. However, there are risks associated with the placement of ZIs, such as penetration of the orbital cavity or infra-temporal fossa. Furthermore, the placement of multiple ZIs makes this surgery risky and more difficult to perform. Potential intraoperative complications are extremely dangerous and may cause irreparable losses. Here, we describe a practical, feasible, and reproducible protocol for a real-time surgical navigation system for precisely placing quad-zygomatic implants in the severely atrophic maxilla of patients with residual bone that does not meet the requirements of conventional implants. Hundreds of patients have received ZIs at our department based on this protocol. The clinical outcomes have been satisfactory, the intraoperative and postoperative complications have been low, and the accuracy indicated by infusion of the designed image and postoperative three-dimensional image has been high. This method should be utilized during the entire surgical procedure to ensure ZI placement safety.

Here, we present a protocol to achieve precise quad-zygomatic implant placement in patients with severely atrophic maxilla using a real-time dynamic navigation system.

Zygomatic implants (ZIs) are an ideal way to address cases of a severely atrophic edentulous maxilla and maxilla defects because they replace extensive ...

Dynamic Navigation for Dental Implant Placement

In modern implantology, the application of surgical navigation systems is becoming increasingly important. In addition to static surgical navigation methods, a guide-independent dynamic navigation implant placement procedure is becoming more widespread. The procedure is based on computer-guided dental implant placement utilizing optical control. This work aims to demonstrate the technical steps of a new dynamic computer-aided implant surgery (DCAIS)&#160;system (design, calibration, surgery) and check the accuracy of the results. Based on cone-beam computed tomography (CBCT) scans, the exact positions of implants are determined with dedicated software. The first step of the operation is the calibration of the navigation system, which can be performed in two ways: 1) based on CBCT images taken with a marker or 2) based on CBCT images without markers. Implants are inserted with the aid of real-time navigation according to the preoperative plans. The accuracy of the interventions can be evaluated based on postoperative CBCT images. The preoperative images containing the planned positions of the implants and postoperative CBCT images were compared based on the angulation (degree), platform, and apical deviation (mm) of the implants. To evaluate the data, we calculated the standard deviation (SD), mean, and standard error of the mean (SEM) of deviations within planned and performed implant positions. Differences between the two calibration methods were compared based on this data. Based on the interventions performed so far, the use of DCAIS allows for high-precision implant placement. A calibration system that does not require labeled CBCT recording allows for surgical intervention with similar accuracy as a system that uses labeling. The accuracy of the intervention can be improved by training.

Dynamic computer-aided implant surgery (DCAIS) is a controlled implant surgical placement method performed without a surgical template using optical control. The real-time intraoperative control of movement and position of the surgical device simplifies the procedure and gives more freedom to the surgeon, providing similar precision as static navigation methods.

In modern implantology, the application of surgical navigation systems is becoming increasingly important. In addition to static surgical navigation ...

Guided Endodontics: Three-Dimensional Planning and Template-Aided Preparation of Endodontic Access Cavities

Pulp canal obliterations (PCO) are often a consequence of dental trauma, such as luxation injuries. Even though dentin apposition is a sign of vital pulp, pulpitis or apical periodontitis may develop in the long term. Root canal treatment of teeth with severe PCO and pulpal or periapical pathosis is challenging for general practitioners and even for well-equipped endodontic specialists. To ensure detection of the calcified root canal and avoid excessive loss of tooth structure or root perforation, static navigation using templates ("Guided Endodontics") was introduced a few years ago. The general workflow includes three-dimensional imaging using cone-beam computed tomography (CBCT), a digital surface scan, and superimposition of both in a planning software. This is followed by virtual planning of the access cavity and the design of a template that will guide the drill to the desired target point. To do this, a true-to-scale virtual image of the drill must be placed in a way that the tip of the drill reaches the orifice of the calcified root canal. Once the template has been fabricated using computer-aided design and computer-aided manufacturing (CAD/CAM) or a 3D printer, guided preparation of the access cavity can be performed clinically. For research purposes, a postoperative CBCT image can be used to quantify the accuracy of the access cavity performed. This work aims to present the technique of static guided endodontics from imaging to clinical implementation.

Guided endodontics describes a template-aided approach for access cavity preparation. The procedure requires cone-beam computed tomography and a surface scan to produce a template. An incorporated sleeve guides the drill to the target point. This allows the preparation of minimally invasive endodontic access cavities in calcified teeth.

Pulp canal obliterations (PCO) are often a consequence of dental trauma, such as luxation injuries. Even though dentin apposition is a sign of vital pulp, ...

Augmented Reality Navigation-Guided Core Decompression for Osteonecrosis of Femoral Head

Osteonecrosis of the femoral head (ONFH) is a common joint disease in young and middle-aged patients, which seriously burdens their lives and work. For early-stage ONFH, core decompression surgery is a classical and effective hip preservation therapy. In traditional procedures of core decompression with Kirschner wire, there are still many problems such as X-ray exposure, repeated puncture verification, and damage to normal bone tissue. The blindness of the puncture process and the inability to provide real-time visualization are crucial reasons for these problems.
To optimize this procedure, our team developed an intraoperative navigation system on the basis of augmented reality (AR) technology. This surgical system can intuitively display the anatomy of the surgical areas and render preoperative images and virtual needles to intraoperative video in real-time. With the guide of the navigation system, surgeons can accurately insert Kirschner wires into the targeted lesion area and minimize the collateral damage. We conducted 10 cases of core decompression surgery with this system. The efficiency of positioning and fluoroscopy is greatly improved compared to the traditional procedures, and the accuracy of puncture is also guaranteed.

Augmented reality technology was applied to core decompression for osteonecrosis of the femoral head to realize real-time visualization of this surgical procedure. This method can effectively improve the safety and precision of core decompression.

Osteonecrosis of the femoral head (ONFH) is a common joint disease in young and middle-aged patients, which seriously burdens their lives and work. For ...