The authors thank Dr. Shengchi Fan for kindly providing valuable navigation technical support. This case report was funded by the Key project of China&#39;s Ministry of Science and Technology (2017YFB1302904), the Natural Science Foundation of Shanghai (No. 21ZR1437700), the Clinical research plan of SHDC (SHDC2020CR3049B), and the Combined Engineering and Medical Project of Shanghai Jiao Tong University (YG2021QN72).

All of the clinical protocols were approved by the Medical Ethics Review Committee of the Shanghai Ninth People&#39;s Hospital, Shanghai Jiao Tong University, School of Medicine (SH9H-2020-T29-3).
1. Patient selection
<ol>
	<li>The patient inclusion criteria were as follows (Table 1).
	<ol>
		<li>Ensure that the patient presents a completely edentulous maxilla or partially edentulous maxilla with few extremely loose teeth (Figure 1A-G).</li>
		<li>Ensure that the patient has severe atrophy of the maxilla and insufficient bone volume for conventional implant placement in the anterior and/or posterior maxilla.</li>
		<li>Ensure that the patient is aged within 18-80 years and does not have systemic disease.</li>
		<li>Ensure that the patient has undergone cone beam computed tomography (CBCT) with analyzed DICOM data9. 
		NOTE: The preoperative CBCT is obtained using a commercial instrument with the following scanning parameters: 7.1 mA, 96 kV, 0.4 mm voxel size, field of view of 23 cm (D) x 26 cm (H), and scan time of 18 s.
		<ol>
			<li>Using a planning software, confirm that the maxillary posterior bone height ranges from 1 to 3 mm in the premolar and molar regions (Cawood and Howell Class VI)11 (Table 2).</li>
			<li>Ensure that the measured anterior maxilla has an insufficient width to place regular implants of at least 3.75 mm diameter without additional bone grafting or insufficient height to allow the placement of implants shorter than 10 mm even with a titled approach7,12,13 (Figure 1G1-G6). 
			NOTE: The bone thickness for placing the apex of the ZI should at least be 5.75 mm14 (Fig. 2A - B) (Table 1).</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>The patient exclusion criteria were as follows (Table 1).
	<ol>
		<li>Sufficient bone for conventional implant treatment.</li>
		<li>Narrow residual bone for which buccal bone graft is considered more appropriate.</li>
		<li>Untreated maxillary sinusitis or a maxillary sinus cyst.</li>
		<li>Local or systemic contraindications for oral surgery and implant placement.</li>
		<li>For edentulous patients, the maxillary residual bone volume does not meet the standard of classes V or VI of the Cawood Howell classification11.</li>
	</ol>
	</li>
</ol>
2. Mini-screw implantation
<ol>
	<li>Administer local anesthesia to anesthetize the patient&#39;s maxilla, bilateral maxillary tuberosity, midline palatine suture, and both sides of the anterior nasal spine.</li>
	<li>Implant seven to eight mini-screws (diameter: 1.0 mm, length: 9.0 mm, square cavity: 1.0 mm) in the remaining maxilla under local anesthesia to act as registration points before trajectories planning in the bilateral tubera maxillae, midline palatine suture, and nasospinale.</li>
	<li>Select the bilateral maxillary tuberosity, midline palatine suture, and both sides of the anterior nasal spine as the bone anchorage areas for fiducials (Figure 3A-C). 
	NOTE: To increase the navigation accuracy, the mini-screws should be evenly and dispersedly placed in the indicated area.</li>
</ol>
3. Preoperative CBCT scanning for planning
<ol>
	<li>Perform CBCT using the following scanning parameters: 7.1 mA, 96 kV, 0.4 mm voxel size, field of view 23 cm (D) x 26 cm (H), and scan time of 18 s.</li>
</ol>
4. Setting registration points
<ol>
	<li>Import CBCT data into the presurgical planning software through the DVD drive.</li>
	<li>Mark all mini-screws as registration points for intraoperative imaging registration (Figure 3D).
	<ol>
		<li>Mark the points on the central surface of the titanium mini-screws; this has to be set in a certain sequence. 
		NOTE: After the registration points are set, ensure that the intraoral coronal entrance points of the ZI are at or near the alveolar crest with the reference to the zygomatic anatomy-guided approach proposed by Carlos Aparicio15. The anterior ZI should be at the level of the lateral incisor/canine region and the posterior ZI in the second premolar/the first molar region. The apex of the mesial implant should be placed above that of the distal implant. According to the previous research, the posterosuperior region and the center of the zygoma were the ideal places for the apex of the mesial implant and the apex of the distal implant16. The length could only be chosen in the range of 30.0 to 52.5 mm. Cylindroid trajectories can be planned as the drilling path (Figure 3E-K).</li>
	</ol>
	</li>
</ol>
5. Planning for quad-ZI surgery
NOTE: This protocol requires the navigation system.
6. Surgical procedure
<ol>
	<li>Lay the patient on the operating table in the supine position after general anesthesia. 
	NOTE: It is best to situate the patient in this position before he or she is placed under general anesthesia. Otherwise, it is difficult to switch the position.</li>
	<li>Fixed skull reference: Rigidly secure the skull reference base to the calvaria with a single self-tapping titanium screw of 1.5 x 6 mm. Secure the reference array to the base and assemble with three marked reflective spheres (Figure 4A-C). Place the navigation system camera in the 1 o&#39;clock position to monitor the skull reference.</li>
	<li>Registration: Specifically set the navigation system to the individual patient using a positioning probe with a tailor-made reflective ball to contact the outer surface of the mini-screws one after another. Then, display the available sagittal, coronal, axial, and 3D reconstruction images on the navigation screen (Figure 4D-E). 
	NOTE: After the registration procedure, check every fiducial marker for precision. The result is acceptable if the error is mostly &#60;1.0 mm. Otherwise, the registration procedure should be repeated until the error becomes acceptable.</li>
	<li>Standardization: Standardize the drilling before using it in the surgery. Use a calibration block with holes of different diameters to standardize the drill: diameter 2.5 mm (round bur), 2.9 mm (pilot drill), and 3.5 mm (expending drill). The drills should be straightly attached to the bottom of the block by the surgeon, and then the assistant needs to adjust the interface into the calibration module. The equipment will produce a sound once the process is complete.</li>
	<li>Gingiva flap opening: Determine the extent of the incision with the guidance of surgical navigation. Lift the full thickness flap to allow an adequate view for exposing the planned implant sites. 
	NOTE: The range of the periosteal elevation should contain the alveolar crest, lateral wall of the maxilla, and the inferior border of the zygomatic bone.</li>
	<li>Entrance point marking: First, find the entry point with the help of the navigation probe. Then, use the zygoma handpiece to fix the entry points. Next, find the entry of the zygomatic bone with the probe. Use the zygoma handpiece to prepare the entry point of the zygomatic bone (Figure 4F-G). 
	NOTE: Ensure that both the operator and the assistants pay attention to the real surgical area to prevent errors made by the navigation system.</li>
	<li>Initial preparation: Perform the drilling procedure ensuring that it follows the trajectories from the entry to the exit point as planned. Use the 2.9 mm drill first to prepare the path from the entry point, which was located using the navigation probe, to the entry of the zygomatic bone. Prepare the mesial one first, followed by the distal one. 
	NOTE: Check each step with the navigation probe to confirm that the path is correct according to the designed preoperative plan (Figure 4H-I).</li>
	<li>Widen the implant bed: Use the handpiece to extend the path from the entrance of the zygomatic bone to the terminal point designed at the surface of the zygomatic bone. 
	NOTE: Ask the assistant to put a hand on the surface of the lateral orbital wall to ensure its safety. Ensure that the surgeon pays attention to the navigation screen rather than the surgical area.</li>
	<li>Readings and measurements: Enlarge the trajectory with an expanding drill having a 3.5 mm diameter. Use the measuring bar and navigation probe to check the direction and position of the trajectory. Identify the length of the implant using the measuring tool (Figure 4B). 
	NOTE: If the depth does not meet the requirement of the planned length, it is better to prepare it to the set depth.</li>
	<li>Implantation: Implant the ZIs using a specific manual tool.</li>
	<li>Suturing: After ZI implantation, use the navigation probe to verify correct positioning. Place multi-unit abutments and healing caps on the implants and suture the incision with polypropylene 4-0 suture. The hairline incision should also be sutured after the reference frame is removed.</li>
</ol>
7. Postoperative medication
<ol>
	<li>Administer the patient a 5-day prescription of antibiotics, analgesics, and mouthwash solution (chlorhexidine 0.12%).</li>
</ol>
8. Immediate restoration
<ol>
	<li>Perform immediate restoration in the patient within 72 h (Figure 5C-G).</li>
</ol>
9. Image integration
<ol>
	<li>Obtain postoperative CBCT scanning images and a panoramic radiograph to evaluate the ZI position within 72 h after surgery (Figure 5A-B). Export the postoperative data to the planning software to superimpose the image of the post-operative CBCT and the preoperative surgical plan comparing the location of the entrance point, end point, and angular deviation (Figure 5H-I, Table 4).</li>
</ol>

<ol>
	<li>Francischone, C. L., Vasconcelos, L. W., Filho, H. N., Francischone, C. E., Sartori, I. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+15.+The+zygoma+fixture.">Chapter 15. The zygoma fixture.</a> The osseointegration book. From calvarium to calcaneus. , 317-320 (2005).</li><li>Weischer, T., Schettler, D., Mohr, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Titanium+implants+in+the+zygoma+as+retaining+elements+after+hemimaxillectomy.">Titanium implants in the zygoma as retaining elements after hemimaxillectomy.</a> The International Journal of Oral &amp; Maxillofacial Implants. 12 (2), 211-214 (1997).</li><li>Jensen, O. T., Brownd, C., Blacker, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nasofacial+prostheses+supported+by+osseointegrated+implants.">Nasofacial prostheses supported by osseointegrated implants.</a> The International Journal of Oral &amp; Maxillofacial Implants. 7 (2), 203-211 (1992).</li><li>Duarte, L. R., Filho, H. N., Francischone, C. E., Peredo, L. G., Branemark, P. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+establishment+of+a+protocol+for+the+total+rehabilitation+of+atrophic+maxillae+employing+four+zygomatic+fixtures+in+an+immediate+loading+system--a+30-month+clinical+and+radiographic+follow-up.">The establishment of a protocol for the total rehabilitation of atrophic maxillae employing four zygomatic fixtures in an immediate loading system--a 30-month clinical and radiographic follow-up.</a> Clinical Implant Dentistry and Related Research. 9 (4), 186-196 (2007).</li><li>Hung, K. 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=Accuracy+of+a+real-time+surgical+navigation+system+for+the+placement+of+quad+zygomatic+implants+in+the+severe+atrophic+maxilla:+A+pilot+clinical+study.">Accuracy of a real-time surgical navigation system for the placement of quad zygomatic implants in the severe atrophic maxilla: A pilot clinical study.</a> Clinical Implant Dentistry and Related Research. 19 (3), 458-465 (2017).</li><li>Wu, Y., Wang, F., Huang, W., Fan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+navigation+in+zygomatic+implant+placement:+Workflow.">Real-time navigation in zygomatic implant placement: Workflow.</a> Oral and Maxillofacial Surgery Clinics of North America. 31 (3), 357-367 (2019).</li><li>Wang, 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=Reliability+of+four+zygomatic+implant-supported+prostheses+for+the+rehabilitation+of+the+atrophic+maxilla:+a+systematic+review.">Reliability of four zygomatic implant-supported prostheses for the rehabilitation of the atrophic maxilla: a systematic review.</a> The International Journal of Oral &amp; Maxillofacial Implants. 30 (2), 293-298 (2015).</li><li>Xiaojun, C., 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=An+integrated+surgical+planning+and+virtual+training+system.">An integrated surgical planning and virtual training system.</a> IEEE 2010 International Conference on Audio, Language and Image Processing (ICALIP). , 1257-1261 (2010).</li><li>Fan, S., 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+effect+of+the+configurations+of+fiducial+markers+on+accuracy+of+surgical+navigation+in+zygomatic+implant+placement:+An+in+vitro+study.">The effect of the configurations of fiducial markers on accuracy of surgical navigation in zygomatic implant placement: An in vitro study.</a> The International Journal of Oral &amp; Maxillofacial Implants. 34 (1), 85-90 (2019).</li><li>Xiaojun, C., Ming, Y., Yanping, L., Yiqun, W., Chengtao, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Image+guided+oral+implantology+and+its+application+in+the+placement+of+zygoma+implants.">Image guided oral implantology and its application in the placement of zygoma implants.</a> Computer Methods and Programs in Biomedicine. 93 (2), 162-173 (2009).</li><li>Cawood, J. I., Howell, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+classification+of+the+edentulous+jaws.">A classification of the edentulous jaws.</a> The International Journal of Oral &amp; Maxillofacial Surgery. 17 (4), 232-236 (1988).</li><li>Davo, R., Pons, O., Rojas, J., Carpio, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immediate+function+of+four+zygomatic+implants:+a+1-year+report+of+a+prospective+study.">Immediate function of four zygomatic implants: a 1-year report of a prospective study.</a> European Journal of Oral Implantology. 3 (4), 323-334 (2010).</li><li>Jensen, O. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complete+arch+site+classification+for+all-on-4+immediate+function.">Complete arch site classification for all-on-4 immediate function.</a> The Journal of Prosthetic Dentistry. 112 (4), 741-751 (2014).</li><li>Triplett, R. G., Schow, S. R., Laskin, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+and+maxillofacial+surgery+advances+in+implant+dentistry.">Oral and maxillofacial surgery advances in implant dentistry.</a> The International Journal of Oral &amp; Maxillofacial Implants. 15 (1), 47-55 (2000).</li><li>Aparicio, 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+proposed+classification+for+zygomatic+implant+patient+based+on+the+zygoma+anatomy+guided+approach+(ZAGA):+a+cross-sectional+survey.">A proposed classification for zygomatic implant patient based on the zygoma anatomy guided approach (ZAGA): a cross-sectional survey.</a> European Journal of Oral Implantology. 4 (3), 269-275 (2011).</li><li>Hung, K. 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=Measurement+of+the+zygomatic+region+for+the+optimal+placement+of+quad+zygomatic+implants.">Measurement of the zygomatic region for the optimal placement of quad zygomatic implants.</a> Clinical Implant Dentistry and Related Research. 19 (5), 841-848 (2017).</li><li>Kahnberg, K. E., Nystrom, E., Bartholdsson, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combined+use+of+bone+grafts+and+Br+fixtures+in+the+treatment+of+severely+resorbed+maxillae.">Combined use of bone grafts and Br fixtures in the treatment of severely resorbed maxillae.</a> The International Journal of Oral &amp; Maxillofacial Implants. 4 (4), 297-304 (1989).</li><li>Nystrom, E., Kahnberg, K. E., Gunne, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bone+grafts+and+Br+implants+in+the+treatment+of+the+severely+resorbed+maxilla:+A+2-year+longitudinal+study.">Bone grafts and Br implants in the treatment of the severely resorbed maxilla: A 2-year longitudinal study.</a> The International Journal of Oral &amp; Maxillofacial Implants. 8 (1), 45-53 (1993).</li><li>Jensen, S. S., Terheyden, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bone+augmentation+procedures+in+localized+defects+in+the+alveolar+ridge:+Clinical+results+with+different+bone+grafts+and+bone-substitute+materials.">Bone augmentation procedures in localized defects in the alveolar ridge: Clinical results with different bone grafts and bone-substitute materials.</a> The International Journal of Oral &amp; Maxillofacial Implants. 24, 218-236 (2009).</li><li>Bedrossian, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rehabilitation+of+the+edentulous+maxilla+with+the+zygoma+concept:+A+7-year+prospective+study.">Rehabilitation of the edentulous maxilla with the zygoma concept: A 7-year prospective study.</a> The International Journal of Oral &amp; Maxillofacial Implants. 25 (6), 1213-1221 (2010).</li><li>Dhamankar, D., Gupta, A. R., Mahadevan, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immediate+implant+loading:+A+case+report.">Immediate implant loading: A case report.</a> Journal of Indian Prosthodontic Society. 10 (1), 64-66 (2010).</li><li>Aparicio, C., 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=Zygomatic+implants:+indications,+techniques+and+outcomes,+and+the+zygomatic+success+code.">Zygomatic implants: indications, techniques and outcomes, and the zygomatic success code.</a> Periodontol 2000. 66 (1), 41-58 (2014).</li><li>Chrcanovic, B. R., Abreu, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Survival+and+complications+of+zygomatic+implants:+A+systematic+review.">Survival and complications of zygomatic implants: A systematic review.</a> Journal of Oral and Maxillofacial Surgery. 17 (2), 81-93 (2013).</li><li>Br&#229;nemark, P. 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=Zygoma+fixture+in+the+management+of+advanced+atrophy+of+the+maxilla:+Technique+and+long-term+results.">Zygoma fixture in the management of advanced atrophy of the maxilla: Technique and long-term results.</a> Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. 38 (2), 70-85 (2004).</li><li>Balshi, T. J., Wolfinger, G. J., Petropoulos, V. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quadruple+zygomatic+implant+support+for+retreatment+of+resorbed+iliac+crest+bone+graft+transplant.">Quadruple zygomatic implant support for retreatment of resorbed iliac crest bone graft transplant.</a> Implant Dentistry. 12 (1), 47-53 (2003).</li><li>Chrcanovic, B. R., Oliveira, D. R., Cust&#243;dio, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+evaluation+of+computed+tomography-derived+stereolithographic+surgical+guides+in+zygomatic+implant+placement+in+human+cadavers.">Accuracy evaluation of computed tomography-derived stereolithographic surgical guides in zygomatic implant placement in human cadavers.</a> The Journal of Oral Implantology. 36 (5), 345-355 (2010).</li><li>Gellrich, N. C., 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=Computer-assisted+secondary+reconstruction+of+unilateral+posttraumatic+orbital+deformity.">Computer-assisted secondary reconstruction of unilateral posttraumatic orbital deformity.</a> Plast and Reconstructive Surgery. 110 (6), 1417-1429 (2002).</li><li>Watzinger, 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=Placement+of+endosteal+implants+in+the+zygoma+after+maxillectomy:+A+Cadaver+study+using+surgical+navigation.">Placement of endosteal implants in the zygoma after maxillectomy: A Cadaver study using surgical navigation.</a> Plast and Reconstructive Surgery. 107 (3), 659-667 (2001).</li><li>Wagner, 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=Computer-aided+placement+of+endosseous+oral+implants+in+patients+after+ablative+tumour+surgery:+Assessment+of+accuracy.">Computer-aided placement of endosseous oral implants in patients after ablative tumour surgery: Assessment of accuracy.</a> Clinical Oral Implants Research. 14 (3), 340-348 (2003).</li><li>Casap, N., Wexler, A., Tarazi, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+a+surgical+navigation+system+for+implant+surgery+in+a+deficient+alveolar+ridge+postexcision+of+an+odontogenic+myxoma.">Application of a surgical navigation system for implant surgery in a deficient alveolar ridge postexcision of an odontogenic myxoma.</a> The Journal of Oral &amp; Maxillofacial Surgery. 63 (7), 982-988 (2005).</li><li>Pellegrino, G., Tarsitano, A., Basile, F., Pizzigallo, A., Marchetti, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Computer-aided+rehabilitation+of+maxillary+oncological+defects+using+zygomatic+implants:+A+defect-based+classification.">Computer-aided rehabilitation of maxillary oncological defects using zygomatic implants: A defect-based classification.</a> The Journal of Oral &amp; Maxillofacial Surgery. 73 (12), 1-11 (2015).</li><li>Fan, S., 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+effect+of+the+configurations+of+fiducial+markers+on+accuracy+of+surgical+navigation+in+zygomatic+implant+placement:+An+in+vitro+study.">The effect of the configurations of fiducial markers on accuracy of surgical navigation in zygomatic implant placement: An in vitro study.</a> The International Journal of Oral &amp; Maxillofacial Implants. 34 (1), 85-90 (2019).</li><li>D'Haese, J., Van De Velde, T., Elaut, L., De Bruyn, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+prospective+study+on+the+accuracy+of+mucosally+supported+stereolithographic+surgical+guides+in+fully+edentulous+maxillae.">A prospective study on the accuracy of mucosally supported stereolithographic surgical guides in fully edentulous maxillae.</a> Clinical Implant Dentistry and Related Research. 14 (2), 293-303 (2012).</li><li>St&#252;binger, S., Buitrago-Tellez, C., Cantelmi, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deviations+between+placed+and+planned+implant+positions:+an+accuracy+pilot+study+of+skeletally+supported+stereolithographic+surgical+templates.">Deviations between placed and planned implant positions: an accuracy pilot study of skeletally supported stereolithographic surgical templates.</a> Clinical Implant Dentistry and Related Research. 16 (4), 540-551 (2014).</li></ol>

All the authors state that they have no conflicts of interest.

Reconstructive rehabilitation of the atrophic maxilla using grafts is difficult because it requires good surgical technique, coverage of high-quality soft tissue over the graft, a significant amount of patient cooperation, and patients with health favorable for the finial restoration17,18. The placement of dental implants for reconstruction in patients with maxillary atrophy represents a significant clinical challenge. The pattern of facial bone resorption is ass...

In the 1990s, Branemark introduced an alternative technique for bone grafting, the zygomatic implant (ZI), which has also been called the zygomaticus fixture1. It was initially used for the treatment of trauma victims and patients with tumor resection where there was a defect in the maxillary structure. After maxillectomy, many patients retained anchorage only in the body of the zygoma or in the frontal extension of the zygomatic bone1,2,3.
More recently, the ZI technique has been widely used in edentulous and dentate patients with a severely resorbed maxilla. The main indication for ZI implants is an atrophic maxilla. The use of four ZIs in an immediate loading system (fixed prosthodontics) is practical for surgeons with broad clinical experience, and it appears to represent an excellent alternative method to bone graft techniques2,4. However, there are risks when placing ZIs, either by freehand or using a surgical template for guidance. Risks include inaccurate placement within the alveolus, penetration of the orbital cavity or infra-temporal fossa, and inappropriate placement within the zygomatic prominence5. The placement of multiple ZIs makes this surgery risky and difficult to perform. Hence, improving the precision of ZI placement is critical to its clinical use and safety.
The real-time surgical navigation system provides a different approach. It provides real-time and completely visualized trajectories through the analysis of preoperative and intraoperative computed tomography images. With the real-time navigation system, both precision and safety have been improved with sophisticated surgery and treatment5,6. A practical, feasible, and reproducible protocol was developed using the real-time surgical navigation system to precisely place ZIs in the severely atrophic maxilla5,7,8,9,10. With this protocol, we have treated hundreds of patients with satisfactory clinical outcomes5,6,7,8,9,10. Here, we present the protocol with the detailed information on the treatment procedure.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Bistoury scalpel</td>
			<td>Hufriedy Group</td>
			<td>10-130-05</td>
			<td></td>
		</tr>
		<tr>
			<td>Branemark system zygoma TiUnite RP 35mm</td>
			<td>Nobel Biocare AB</td>
			<td>34724</td>
			<td>TiUnite implant with overlength to place from the maxilla to the zygoma</td>
		</tr>
		<tr>
			<td>Branemark system zygoma TiUnite RP 40mm</td>
			<td>Nobel Biocare AB</td>
			<td>34735</td>
			<td>TiUnite implant with overlength to place from the maxilla to the zygoma</td>
		</tr>
		<tr>
			<td>Branemark system zygoma TiUnite RP 42.5mm</td>
			<td>Nobel Biocare AB</td>
			<td>34736</td>
			<td>TiUnite implant with overlength to place from the maxilla to the zygoma</td>
		</tr>
		<tr>
			<td>Branemark system zygoma TiUnite RP 45mm</td>
			<td>Nobel Biocare AB</td>
			<td>34737</td>
			<td>TiUnite implant with overlength to place from the maxilla to the zygoma</td>
		</tr>
		<tr>
			<td>Branemark system zygoma TiUnite RP 47.5mm</td>
			<td>Nobel Biocare AB</td>
			<td>34738</td>
			<td>TiUnite implant with overlength to place from the maxilla to the zygoma</td>
		</tr>
		<tr>
			<td>Branemark system zygoma TiUnite RP 50mm</td>
			<td>Nobel Biocare AB</td>
			<td>34739</td>
			<td>TiUnite implant with overlength to place from the maxilla to the zygoma</td>
		</tr>
		<tr>
			<td>Branemark system zygoma TiUnite RP 52.5mm</td>
			<td>Nobel Biocare AB</td>
			<td>34740</td>
			<td>TiUnite implant with overlength to place from the maxilla to the zygoma</td>
		</tr>
		<tr>
			<td>CBCT</td>
			<td>Planmeca Oy,Helsinki, Finland</td>
			<td>Pro Max 3D Max</td>
			<td></td>
		</tr>
		<tr>
			<td>connection to handpiece</td>
			<td>Nobel Biocare AB</td>
			<td>29081</td>
			<td>the accessories to connect the intrument</td>
		</tr>
		<tr>
			<td>Drill guard</td>
			<td>Nobel Biocare AB</td>
			<td>29162</td>
			<td>the accessories to protect the lips and soft tissue during the surgery</td>
		</tr>
		<tr>
			<td>Drill guard short</td>
			<td>Nobel Biocare AB</td>
			<td>29162</td>
			<td>the accessories to protect the lips and soft tissue during the surgery</td>
		</tr>
		<tr>
			<td>Handpiece zygoma 20:1</td>
			<td>Nobel Biocare AB</td>
			<td>32615</td>
			<td>the basic instrument for implant drill</td>
		</tr>
		<tr>
			<td>Instrument adapter array size L</td>
			<td>BRAINLAB AG</td>
			<td>41801</td>
			<td></td>
		</tr>
		<tr>
			<td>Instrument adapter array size M</td>
			<td>BRAINLAB AG</td>
			<td>41798</td>
			<td></td>
		</tr>
		<tr>
			<td>Instrument calibration matrix</td>
			<td>BRAINLAB AG</td>
			<td>41874</td>
			<td>a special tool for drill to calibration</td>
		</tr>
		<tr>
			<td>I-plan automatic image fusion software STL data import/export for I-plan VectorVision2&#174;, (I-plan CMF software)</td>
			<td>BRAINLAB AG</td>
			<td>inapplicability</td>
			<td>the software for navigation surgery planning</td>
		</tr>
		<tr>
			<td>Multi-unit abutment 3mm</td>
			<td>Nobel Biocare AB</td>
			<td>32330</td>
			<td>the connection accessory between the implant and the titanium base</td>
		</tr>
		<tr>
			<td>Multi-unit abutment 5mm</td>
			<td>Nobel Biocare AB</td>
			<td>32331</td>
			<td>the connection accessory between the implant and the titanium base</td>
		</tr>
		<tr>
			<td>Periosteal elevator</td>
			<td>Hufriedy Group</td>
			<td>PPR3/9A</td>
			<td>the instrument for open flap surgery</td>
		</tr>
		<tr>
			<td>Pilot drill</td>
			<td>Nobel Biocare AB</td>
			<td>32630</td>
			<td>the drill for the surgery</td>
		</tr>
		<tr>
			<td>Pilot drill short</td>
			<td>Nobel Biocare AB</td>
			<td>32632</td>
			<td>the drill for the surgery measuring the depth of the implant holes</td>
		</tr>
		<tr>
			<td>Pointer with blunt tip for cranial/ENT</td>
			<td>BRAINLAB AG</td>
			<td>53106</td>
			<td></td>
		</tr>
		<tr>
			<td>Reference headband star</td>
			<td>BRAINLAB AG</td>
			<td>41877</td>
			<td></td>
		</tr>
		<tr>
			<td>Round bur</td>
			<td>Nobel Biocare AB</td>
			<td>DIA 578-0</td>
			<td>the drill for the surgery</td>
		</tr>
		<tr>
			<td>Screwdriver manual</td>
			<td>Nobel Biocare AB</td>
			<td>29149</td>
			<td></td>
		</tr>
		<tr>
			<td>Skull reference array</td>
			<td>BRAINLAB AG</td>
			<td>52122</td>
			<td>a special made metal reference for navigation camera to receive the signal</td>
		</tr>
		<tr>
			<td>Skull reference base</td>
			<td>BRAINLAB AG</td>
			<td>52129</td>
			<td></td>
		</tr>
		<tr>
			<td>Suture vicryl 4-0</td>
			<td>Johnson &#38;Johnson, Ethicon</td>
			<td>VCP310H</td>
			<td></td>
		</tr>
		<tr>
			<td>Temporary copping multi-unit titanium (with prosthetic screw)</td>
			<td>Nobel Biocare AB</td>
			<td>29046</td>
			<td>the temporary titanium base to fix the teeth</td>
		</tr>
		<tr>
			<td>Titanium mini-screw</td>
			<td>CIBEI</td>
			<td>MB105-2.0*9</td>
			<td>the mini-screw for navigation registration</td>
		</tr>
		<tr>
			<td>Twist drill</td>
			<td>Nobel Biocare AB</td>
			<td>32628</td>
			<td>the drill for the surgery</td>
		</tr>
		<tr>
			<td>Twist drill short</td>
			<td>Nobel Biocare AB</td>
			<td>32629</td>
			<td>the drill for the surgery</td>
		</tr>
		<tr>
			<td>Zygoma depth indicator angled</td>
			<td>Nobel Biocare AB</td>
			<td>29162</td>
			<td></td>
		</tr>
		<tr>
			<td>Zygoma depth indicator straight</td>
			<td>Nobel Biocare AB</td>
			<td>29162</td>
			<td>the measurement scale for</td>
		</tr>
		<tr>
			<td>Zygoma handle</td>
			<td>Nobel Biocare AB</td>
			<td>29162</td>
			<td>the instrument for zygomatic implant placement</td>
		</tr>
	</tbody>
</table>

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.

The enrolled patient was a 60-year-old woman without any systematic diseases (Figure 1A-D, F). After CBCT scanning, the alveolar ridge in the anterior maxilla was less than 2.9 mm, while the residual bone height in the posterior maxilla region was less than 2.4 mm (Figure 1E, G and Table 1). The width and thickness of the zygomatic bone were approximately 22.4-23.6 mm and 6.1-8.0 mm (<strong cla...

Watch this Scientific Journal Video about Real-Time Dynamic Navigation System for the Precise Quad-Zygomatic Implant Placement in a Patient with a Severely Atrophic Maxilla at JoVE.com

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

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 ...

real-time-dynamic-navigation-system-for-precise-quad-zygomatic

Research

JoVE Journal

Medicine

1.7K Views.  National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology. 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.

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

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 ...

Intraoperative Detection of Subtle Endometriosis: A Novel Paradigm for Detection and Treatment of Pelvic Pain Associated with the Loss of Peritoneal Integrity

Endometriosis is a common disease affecting 40 to 70% of reproductive-aged women with chronic pelvic pain (CPP) and/or infertility. The purpose of this study was to demonstrate the use of a blue dye (methylene blue) to stain peritoneal surfaces during laparoscopy (L/S) to detect the loss of peritoneal integrity in patients with pelvic pain and suspected endometriosis. Forty women with CPP and 5 women without pain were evaluated in this pilot study. During L/S, concentrated dye was sprayed onto peritoneal surfaces, then aspirated and rinsed with Lactated Ringers solution. Areas of localized dye uptake were evaluated for the presence of visible endometriotic lesions. Areas of intense peritoneal staining were resected and some fixed in 2.5% buffered gluteraldehyde and examined by scanning (SEM) electron microscopy. Blue dye uptake was more common in women with endometriosis and chronic pelvic pain than controls (85% vs. 40%). Resection of the blue stained areas revealed endometriosis by SEM and loss of peritoneal cell-cell contact compared to normal, non-staining peritoneum. Affected peritoneum was associated with visible endometriotic implants in most but not all patients. Subjective pain relief was reported in 80% of subjects. Based on scanning electron microscopy, we conclude that endometrial cells extend well beyond visible implants of endometriosis and appear to disrupt the underlying mesothelium. Subtle lesions of endometriosis could therefore cause pelvic pain by disruption of peritoneal integrity, allowing menstrual or ovulatory blood and associated pain factors access to underlying sensory nerves. Complete resection of affected peritoneum may provide a better long-term treatment for endometriosis and CPP. This simple technique appears to improve detection of subtle or near invisible endometriosis in women with CPP and minimal visual findings at L/S and may serve to elevate diagnostic accuracy for endometriosis at laparoscopy.

Loss of peritoneal integrity provides a new paradigm to understand and treat chronic pelvic pain in women with mild forms of endometriosis and can be easily detected using intraoperative instillation of dye at the time of laparoscopy.

Endometriosis is a  common disease affecting 40 to 70% of reproductive-aged women with chronic  pelvic pain (CPP) and/or infertility. The purpose of this ...

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 ...

Computerized Dynamic Posturography for Postural Control Assessment in Patients with Intermittent Claudication

Computerized dynamic posturography with the EquiTest is an objective technique for measuring postural strategies under challenging static and dynamic conditions. As part of a diagnostic assessment, the early detection of postural deficits is important so that appropriate and targeted interventions can be prescribed. The Sensory Organization Test (SOT) on the EquiTest determines an individual&#39;s use of the sensory systems (somatosensory, visual, and vestibular) that are responsible for postural control. Somatosensory and visual input are altered by the calibrated sway-referenced support surface and visual surround, which move in the anterior-posterior direction in response to the individual&#39;s postural sway. This creates a conflicting sensory experience. The Motor Control Test (MCT) challenges postural control by creating unexpected postural disturbances in the form of backwards and forwards translations. The translations are graded in magnitude and the time to recover from the perturbation is computed.
Intermittent claudication, the most common symptom of peripheral arterial disease, is characterized by a cramping pain in the lower limbs and caused by muscle ischemia secondary to reduced blood flow to working muscles during physical exertion. Claudicants often display poor balance, making them susceptible to falls and activity avoidance. The Ankle Brachial Pressure Index (ABPI) is a noninvasive method for indicating the presence of peripheral arterial disease and intermittent claudication, a common symptom in the lower extremities. ABPI is measured as the highest systolic pressure from either the dorsalis pedis or posterior tibial artery divided by the highest brachial artery systolic pressure from either arm. This paper will focus on the use of computerized dynamic posturography in the assessment of balance in claudicants.

Individuals with intermittent claudication exhibit poor balance compared to healthy controls. Computerized dynamic posturography is an objective method for measuring an individual's postural responses to balance disturbances. This provides an objective reflection of the person&#x2019;s ability to respond to situations under which sensory stimuli are altered and unexpected perturbations occur.

Computerized dynamic posturography with the EquiTest is an objective technique for measuring postural strategies under challenging static and dynamic ...

Evaluation of Lung Metastasis in Mouse Mammary Tumor Models by Quantitative Real-time PCR

Metastatic disease is the spread of malignant tumor cells from the primary cancer site to a distant organ and is the primary cause of cancer associated death 1. Common sites of metastatic spread include lung, lymph node, brain, and bone 2. Mechanisms that drive metastasis are intense areas of cancer research. Consequently, effective assays to measure metastatic burden in distant sites of metastasis are instrumental for cancer research. Evaluation of lung metastases in mammary tumor models is generally performed by gross qualitative observation of lung tissue following dissection. Quantitative methods of evaluating metastasis are currently limited to ex vivo and in vivo imaging based techniques that require user defined parameters. Many of these techniques are at the whole organism level rather than the cellular level 3-6. Although newer imaging methods utilizing multi-photon microscopy are able to evaluate metastasis at the cellular level 7, these highly elegant procedures are more suited to evaluating mechanisms of dissemination rather than quantitative assessment of metastatic burden. Here, a simple in vitro method to quantitatively assess metastasis is presented. Using quantitative Real-time PCR (QRT-PCR), tumor cell specific mRNA can be detected within the mouse lung tissue.

This protocol describes how to use quantitative Real-time PCR (QRT-PCR) to detect tumor cell specific mRNA representing metastasis within the mouse lung tissue.

Metastatic disease is the spread of malignant tumor cells from the primary cancer site to a distant organ and is the primary cause of cancer associated ...

Quantitative [18F]-Naf-PET-MRI Analysis for the Evaluation of Dynamic Bone Turnover in a Patient with Facetogenic Low Back Pain

Imaging techniques that reflect dynamic bone turnover may aid in characterizing a wide range of bone pathologies. Bone is a dynamic tissue undergoing continuous remodeling with the competing activity of osteoblasts, which produce the new bone matrix, and osteoclasts, whose function is to eliminate mineralized bone. [18F]-NaF is a positron emission tomography (PET) radiotracer that enables visualization of bone metabolism. [18F]-NaF is chemically absorbed into hydroxyapatite in the bone matrix by osteoblasts and can thus noninvasively detect osteoblastic activity, which is occult to conventional imaging techniques. Kinetic modeling of dynamic [18F]-NaF-PET data provides detailed quantitative measures of bone metabolism. Conventional semi-quantitative PET data, which utilizes standardized uptake values (SUVs) as a measure of radiotracer activity, is referred to as a static technique due to its snapshot of tracer uptake in time.&#160; Kinetic modeling, however, utilizes dynamic image data where tracer levels are continuously acquired providing tracer uptake temporal resolution. From the kinetic modeling of dynamic data, quantitative values like blood flow and metabolic rate (i.e., potentially informative metrics of tracer dynamics) can be extracted, all with respect to the measured activity in the image data. When combined with dual modality PET-MRI, region-specific kinetic data can be correlated with anatomically registered high-resolution structural and pathologic information afforded by MRI. The goal of this methodological manuscript is to outline detailed techniques for performing and analyzing dynamic [18F]-NaF-PET-MRI data. The lumbar facet joint is a common site of degenerative arthritis disease and a common cause for axial low back pain.&#160; Recent studies suggest [18F]-NaF-PET may serve as a useful biomarker of painful facetogenic disease.&#160; The human lumbar facet joint will, therefore, be used as a prototypical region of interest for dynamic [18F]-NaF-PET-MRI analysis in this manuscript.

Quantitative [18F]-Naf-PET-MRI Analysis for the Evaluation of Dynamic Bone Turnover in a Patient with Facetogenic Low Back Pain

Imaging techniques that reflect dynamic bone turnover may aid in characterizing a wide range of bone pathologies. We present detailed methodologies for performing and analyzing dynamic [18F]-NaF-PET-MRI data in a patient with facetogenic low back pain using the lumbar facet joints as a prototypical region of interest.

Imaging techniques that reflect dynamic bone turnover may aid in characterizing a wide range of bone pathologies. Bone is a dynamic tissue undergoing ...

Real-Time Assessment of Spinal Cord Microperfusion in a Porcine Model of Ischemia/Reperfusion

Spinal cord injury is a devastating complication of aortic repair. Despite developments for the prevention and treatment of spinal cord injury, its incidence is still considerably high and therefore, influences patient outcome. Microcirculation plays a key role in tissue perfusion and oxygen supply and is often dissociated from macrohemodynamics. Thus, direct evaluation of spinal cord microcirculation is essential for the development of microcirculation-targeted therapies and the evaluation of existing approaches in regard to spinal cord microcirculation. However, most of the methods do not provide real-time assessment of spinal cord microcirculation. The aim of this study is to describe a standardized protocol for real-time spinal cord microcirculatory evaluation using laser-Doppler needle probes directly inserted in the spinal cord. We used a porcine model of ischemia/reperfusion to induce deterioration of the spinal cord microcirculation. In addition, a fluorescent microsphere injection technique was used. Initially, animals were anesthetized and mechanically ventilated. Thereafter, laser-Doppler needle probe insertion was performed, followed by the placement of cerebrospinal fluid drainage. A median sternotomy was performed for exposure of the descending aorta to perform aortic cross-clamping. Ischemia/reperfusion was induced by supra-celiac aortic cross-clamping for a total of 48 min, followed by reperfusion and hemodynamic stabilization. Laser-Doppler Flux was performed in parallel with macrohemodynamic evaluation. In addition, automated cerebrospinal fluid drainage was used to maintain a stable cerebrospinal pressure. After completion of the protocol, animals were sacrificed, and the spinal cord was harvested for histopathological and microsphere analysis. The protocol reveals the feasibility of spinal cord microperfusion measurements using laser-Doppler probes and shows a marked decrease during ischemia as well as recovery after reperfusion. Results showed comparable behavior to fluorescent microsphere evaluation. In conclusion, this new protocol might provide a useful large animal model for future studies using real-time spinal cord microperfusion assessment in ischemia/reperfusion conditions.

Spinal cord microcirculation plays a pivotal role in spinal cord injury. Most methods do not allow real-time assessment of spinal cord microcirculation, which is essential for the development of microcirculation-targeted therapies. Here, we propose a protocol using Laser-Doppler-Flow Needle probes in a large animal model of ischemia/reperfusion.

Spinal cord injury is a devastating complication of aortic repair. Despite developments for the prevention and treatment of spinal cord injury, its ...

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 ...

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.

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 ...

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.