Name: in vitro application of a wireless sensor in flexion-extension gap balance of unicompartmental knee arthroplasty
Uploaded: 2023-05-05T12:40:00
Description: Watch this Scientific Journal Video about In Vitro Application of a Wireless Sensor in Flexion-Extension Gap Balance of Unicompartmental Knee Arthroplasty at JoVE.com

This work was supported by Beijing Hospitals Authority Clinical Medicine Development of Special Funding Support [grant numbers: XMLX202139]. We would like to express our gratitude to Diego Wang for valuable suggestions.

The protocol was approved by the Ethics Committee of Xuanwu Hospital (grant number: 2021-224) and was conducted in accordance with the Declaration of Helsinki. Informed consent was obtained from next of kin to use the cadavers.
1. Installation of angle measuring device
<ol>
	<li>Turn on the switch of the femur and tibia angle measuring device. Open the angle measurement software on the tablet computer, scan the QR codes of the two measuring devices, and click Bluetoo...

<ol>
	<li>Spitaels, D., 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=Epidemiology+of+knee+osteoarthritis+in+general+practice:+a+registry-based+study.">Epidemiology of knee osteoarthritis in general practice: a registry-based study.</a> BMJ Open. 10 (1), 031734 (2020).</li><li>Heaps, B. M., Blevins, J. L., Chiu, Y. 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=Improving+estimates+of+annual+survival+rates+for+medial+unicompartmental+knee+arthroplasty,+a+meta-analysis.">Improving estimates of annual survival rates for medial unicompartmental knee arthroplasty, a meta-analysis.</a> The Journal of Arthroplasty. 34 (7), 1538-1545 (2019).</li><li>Goodfellow, J. W., O'Connor, J. J., Pandit, H., Dodd, C. 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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=Risk+of+revision+for+medial+unicompartmental+knee+arthroplasty+according+to+fixation+and+bearing+type+:+short-+to+mid-term+results+from+the+Dutch+Arthroplasty+Register.">Risk of revision for medial unicompartmental knee arthroplasty according to fixation and bearing type : short- to mid-term results from the Dutch Arthroplasty Register.</a> The Bone &amp; Joint Journal. 103 (7), 1261-1269 (2021).</li><li>Ridgeway, S. R., McAuley, J. P., Ammeen, D. J., Engh, G. A. <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+alignment+of+the+knee+on+the+outcome+of+unicompartmental+knee+replacement.">The effect of alignment of the knee on the outcome of unicompartmental knee replacement.</a> The Journal of Bone and Joint Surgery. 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H., Ackroyd, C. E., Shah, N. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unicompartmental+or+total+knee+replacement?+Five-year+results+of+a+prospective,+randomised+trial+of+102+osteoarthritic+knees+with+unicompartmental+arthritis.">Unicompartmental or total knee replacement? Five-year results of a prospective, randomised trial of 102 osteoarthritic knees with unicompartmental arthritis.</a> The Journal of Bone and Joint Surgery. British Volume. 80 (5), 862-865 (1998).</li><li>Yang, K. Y., Wang, M. C., Yeo, S. J., Lo, N. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimally+invasive+unicondylar+versus+total+condylar+knee+arthroplasty-early+results+of+a+matched-pair+comparison.">Minimally invasive unicondylar versus total condylar knee arthroplasty-early results of a matched-pair comparison.</a> Singapore Medical Journal. 44 (11), 559-562 (2003).</li><li>Watson, J., Smith, V., Schmidt, D., Navratil, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automatic+implantable+cardioverter-defibrillator:+early+experience+at+Wilford+Hall+USAF+Medical+Center.">Automatic implantable cardioverter-defibrillator: early experience at Wilford Hall USAF Medical Center.</a> Southern Medical Journal. 85 (2), 161-163 (1992).</li><li>D'Ambrosi, R., Vaishya, R., Verde, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Balancing+in+unicompartmental+knee+arthroplasty:+balancing+in+flexion+or+in+extension.">Balancing in unicompartmental knee arthroplasty: balancing in flexion or in extension.</a> Journal of Clinical Medicine. 11 (22), 6813 (2022).</li><li>Collier, M. B., Eickmann, T. H., Anbari, K. K., Engh, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lateral+tibiofemoral+compartment+narrowing+after+medial+unicondylar+arthroplasty.">Lateral tibiofemoral compartment narrowing after medial unicondylar arthroplasty.</a> Clinical Orthopaedics and Related Research. 464, 43-52 (2007).</li><li>Collier, M. B., Eickmann, T. H., Sukezaki, F., McAuley, J. P., Engh, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patient,+implant,+and+alignment+factors+associated+with+revision+of+medial+compartment+unicondylar+arthroplasty.">Patient, implant, and alignment factors associated with revision of medial compartment unicondylar arthroplasty.</a> The Journal of Arthroplasty. 21 (6), 108-115 (2006).</li><li>D'Ambrosi, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radiographic+and+clinical+evolution+of+the+Oxford+unicompartmental+knee+arthroplasty.">Radiographic and clinical evolution of the Oxford unicompartmental knee arthroplasty.</a> The Journal of Knee Surgery. 36 (3), 246-253 (2023).</li><li>Koskinen, E., Paavolainen, P., Eskelinen, A., Pulkkinen, P., Remes, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unicondylar+knee+replacement+for+primary+osteoarthritis:+a+prospective+follow-up+study+of+1,819+patients+from+the+Finnish+Arthroplasty+Register.">Unicondylar knee replacement for primary osteoarthritis: a prospective follow-up study of 1,819 patients from the Finnish Arthroplasty Register.</a> Acta Orthopaedica. 78 (1), 128-135 (2007).</li><li>ten Ham, A. M., Heesterbeek, P. J. C., vander Schaaf, D. B., Jacobs, W. C. H., Wymenga, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexion+and+extension+laxity+after+medial,+mobile-bearing+unicompartmental+knee+arthroplasty:+a+comparison+between+a+spacer-+and+a+tension-guided+technique.">Flexion and extension laxity after medial, mobile-bearing unicompartmental knee arthroplasty: a comparison between a spacer- and a tension-guided technique.</a> Knee Surgery, Sports Traumatology, Arthroscopy. 21 (11), 2447-2452 (2013).</li><li>Clarius, M., Seeger, J. B., Jaeger, S., Mohr, G., Bitsch, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+importance+of+pulsed+lavage+on+interface+temperature+and+ligament+tension+force+in+cemented+unicompartmental+knee+arthroplasty.">The importance of pulsed lavage on interface temperature and ligament tension force in cemented unicompartmental knee arthroplasty.</a> Clinical Biomechanics. 27 (4), 372-376 (2012).</li><li>Heyse, T. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Balancing+UKA:+overstuffing+leads+to+high+medial+collateral+ligament+strains.">Balancing UKA: overstuffing leads to high medial collateral ligament strains.</a> Knee Surgery, Sports Traumatology, Arthroscopy. 24 (10), 3218-3228 (2016).</li><li>Heyse, T. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Balancing+mobile-bearing+unicondylar+knee+arthroplasty+in+vitro.">Balancing mobile-bearing unicondylar knee arthroplasty in vitro.</a> Knee Surgery, Sports Traumatology, Arthroscopy. 25 (12), 3733-3740 (2017).</li><li>Jaeger, 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+influence+of+the+femoral+force+application+point+on+tibial+cementing+pressure+in+cemented+UKA:+an+experimental+study.">The influence of the femoral force application point on tibial cementing pressure in cemented UKA: an experimental study.</a> Archives of Orthopaedic and Trauma Surgery. 132 (11), 1589-1594 (2012).</li><li>Peersman, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinematics+of+mobile-bearing+unicompartmental+knee+arthroplasty+compared+to+native:+results+from+an+in+vitro+study.">Kinematics of mobile-bearing unicompartmental knee arthroplasty compared to native: results from an in vitro study.</a> Archives of Orthopaedic and Trauma Surgery. 137 (11), 1557-1563 (2017).</li><li>Sun, X., 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=Sensor+and+machine+learning-based+assessment+of+gap+balancing+in+cadaveric+unicompartmental+knee+arthroplasty+surgical+training.">Sensor and machine learning-based assessment of gap balancing in cadaveric unicompartmental knee arthroplasty surgical training.</a> International Orthopaedics. 45 (11), 2843-2849 (2021).</li></ol>

Mobile-bearing UKA is an effective treatment for anteromedial KOA. It has the advantages of less trauma, quick recovery, and maintaining normal knee proprioception11,12,13. The key to UKA is flexion-extension balance; that is, making the flexion gap and extension gap as equal as possible on the premise of restoring MCL tension14. The imbalance may lead to bearing dislocation, prosthesis wear, or progressi...

Knee osteoarthritis (KOA) is a global burden1, for which the stepwise treatment strategy is currently adopted. For end-stage unicompartmental KOA, unicompartmental knee arthroplasty (UKA) is an effective choice, with a 10-year survival rate of over 90%2. Medial UKA only replaces the severely worn medial compartment and preserves the natural lateral compartment, medial collateral ligament (MCL), and cruciate ligament3. The principle is to make the flexion gap and extension gap approximately the same by tibial osteotomy and femoral grinding, and to restore MCL tension after implantation of the prosthesis and bearing4. Compared with total knee arthroplasty, UKA has greater surgical difficulty and technical requirements. The main source is the proper balance of ligaments throughout the full range of motion of the knee3.
Traditionally, after preliminary osteotomy, the surgeon inserts a gap gauge in the joint space and indirectly determines whether the flexion and extension gaps are equal by feeling the tension of the MCL. However, the definition and sensation of balance are hardly the same, even for experienced surgeons. For beginners, it is more difficult to grasp the requirement of balance. The imbalance of the flexion-extension gap can lead to a series of complications5,6, resulting in an increased revision rate.
With the advancement of technology, some researchers have tried to apply tensors to UKA7,8. However, these researches are all on the fixed-bearing UKA, and the tensor may damage the MCL when used.
The emergence of sensors not only meets the demand for displaying the pressure in the knee joint gap, but various sensors often have less risk of MCL damage due to their small size9,10. In addition, the sensors currently used are all wired transmission, which may interfere with the aseptic operation and is not convenient enough to use.
In order to accurately measure the flexion-extension gap balance parameters, we developed a wireless sensor combination for UKA, which consists of a metal base, a wireless sensor with three pressure probes on the front, medial, and lateral sides, and a cushion block. The sensor combination measures and displays the pressure in the joint space in real time to help surgeons accurately assess whether the balance target has been achieved.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>angle measuring device</td>
			<td>AIQIAO(SHANGHAI) MEDICAL TECHNOLOGY CO., LTD.</td>
			<td>20203010141</td>
			<td>angle measuring device of femur,angle measuring device of tibia</td>
		</tr>
		<tr>
			<td>Oxford Partial Knee System</td>
			<td>Biomet UK LTD.</td>
			<td>20173130347</td>
			<td>Oxford UKA</td>
		</tr>
		<tr>
			<td>Wireless sensor combination</td>
			<td>AIQIAO(SHANGHAI) MEDICAL TECHNOLOGY CO., LTD.</td>
			<td>20212010325</td>
			<td>a metal base,&#160; a wireless sensor with three pressure probes, and a cushion block</td>
		</tr>
	</tbody>
</table>

in vitro application of a wireless sensor in flexion-extension gap balance of unicompartmental knee arthroplasty

Unicompartmental knee arthroplasty (UKA) is an effective treatment for end-stage anteromedial osteoarthritis (AMOA). The key to UKA is the flexion-extension gap balance, which is closely related to postoperative complications such as bearing dislocation, bearing wear, and arthritis progression. The traditional gap balance assessment is performed by indirectly sensing the tension of the medial collateral ligament by a gap gauge. It relies on the surgeon's feel and experience, which is imprecise and difficult for beginners. To accurately assess the flexion-extension gap balance of UKA, we developed a wireless sensor combination consisting of a metal base, a pressure sensor, and a cushion block. After osteotomy, the insertion of a wireless sensor combination allows the real-time measurement of intra-articular pressure. It accurately quantifies the flexion-extension gap balance parameters to guide further femur grinding and tibia osteotomy, to improve the accuracy of gap balance. We conducted an in vitro experiment with the wireless sensor combination. the results showed that there was a difference of 11.3 N after applying the traditional method of flexion-extension gap balance performed by an experienced expert.

This in vitro study was performed on a 60-year-old female cadaver. With the S-size femoral prosthesis and 3 mm bearing the target, after performing femoral grinding and tibial osteotomy, the surgeon used the gap gauge to assess flexion-extension gap tension preliminarily and believed that balance was achieved.
After the femoral trial was installed, the wireless sensor was inserted into the medial joint space, and the intra-articular pressure was measured three times at 110&#176; (flex...

Watch this Scientific Journal Video about In Vitro Application of a Wireless Sensor in Flexion-Extension Gap Balance of Unicompartmental Knee Arthroplasty at JoVE.com

In Vitro Application of a Wireless Sensor in Flexion-Extension Gap Balance of Unicompartmental Knee Arthroplasty

This protocol presents a cadaveric study of a wireless sensor used in medial unicompartmental knee arthroplasty. The protocol includes the installation of an angle measuring device, standardized Oxford unicompartmental knee arthroplasty osteotomy, preliminary assessment of flexion-extension balance, and application of the sensor to measure flexion-extension gap pressure.

In Vitro Application of a Wireless Sensor in Flexion-Extension Gap Balance of Unicompartmental Knee Arthroplasty

Unicompartmental knee arthroplasty (UKA) is an effective treatment for end-stage anteromedial osteoarthritis (AMOA). The key to UKA is the ...

Our wireless sensor quantifies the pressure parameters of the flexion-extension gap balance in real-time, which is the key to unicompartmental knee arthroplasty. The sensor can display the compartment pressure in real-time, helping the surgeon to assess the flexion-extension balance more accurately and enables wireless data transmission to meet intraoperative sterility requirements. UKA is an important treatment for osteoarthritis of the knee, and the sensor used in this protocol can help with the dynamic intraoperative assessment of the UKA, which is critical to its success.This sensor is specially designed for the mobile-bearing UKA and it can perfectly fit UKA's prosthetic trial. In addition, we have designed matching sensors for different prosthetic sizes. This sensor is specially designed for UKA beginners to shorten their learning curve.The sensor is very easy to operate and there are no specific techniques. Begin by switching on the femur and tibia angle measurement device. Open the angle measurement software on the computer.Scan the QR codes of the two measuring devices and click Bluetooth connection. Place the two angle measurement instruments on a horizontal table and click the Calibration button to calibrate. Tie the instruments with straps on the knee to measure knee flexion angle in real-time.Place a cadaver in the supine position with the lower extremities draped in flexion and abduction over the outside of the operating table. Using the medial parapatellar approach, open the joint cavity with a scalpel. Now, make an incision about three centimeters distal to the joint line along the apex of the medial patella border, ending it distally about one centimeter medial to the tibial tuberosity.Using a rongeur, remove the osteophytes of the medial femoral condyle, intercondylar fossa, and the anterior tibia. Insert a one millimeter femoral sizing spoon into the medial compartment to determine the size of the joint space with cartilage. Insert different sizes of femoral sizing spoons to hook the posterior femoral condyle.When the end of the spoon is about one millimeter away from the cartilage surface, the size of the femoral prosthesis corresponding to the spoon is chosen. Next, connect a three millimeter G-clamp to a tibial saw guide and a femoral sizing spoon. Ensure the guide's shaft is parallel to the tibial long axis in both coronal and sagittal planes and that the ankle yoke points to the ipsilateral anterior superior iliac spine.Use the reciprocating saw to make a vertical tibial saw cut. Advance the saw vertically down until it rests on the surface of the saw guide. Remove the shim from the tibial resection guide and insert the slotted zero shim, then use the oscillating saw blade to excise the plateau.Now, remove the slotted shim, lever the plateau up with a broad osteotome, and remove it with the knee in extension. Make a hole in the distal femoral condyle. Insert the intramedullary rod in the hole.Next, connect the femoral drill guide to the intramedullary rod and perform femoral drilling. Install the posterior resection guide into the drilled holes of the femur. Using the oscillating saw, perform the posterior femoral condyle osteotomy and remove the guide and the bone fragment.Next, excise the medial meniscus, leaving a small cuff of the meniscus to protect the MCL. Completely remove the posterior horn. Insert a zero femoral spigot and attach the spherical mill onto the spigot to perform distal femoral milling, Insert a femoral trial and assess the flexion-extension gap by the gap gauge.Use angle measurement devices to monitor the flexion angle. Insert the gap gauge into the joint space with slight resistance to define the flexion-extension gap balance. If the gaps are not equal, grind the femur according to the difference values until equal.Remove the sensor magnetic induction power switch. Open the pressure measurement software on the tablet computer. Scan the sensor QR code and enter the measurement interface.Click the Connect Device button. Select the appropriate thickness cushion block according to the gauge specification. Put the sensor on the metal base and install the cushion block on the sensor.Click Start Working on the tablet computer. Insert the wireless sensor combination into the medial compartment and fit the metal base to the tibial osteotomy surface. Measure the flexion and extension gap pressure at 110 degrees and at 20 degrees of knee flexion.Calculate the average values separately for three consecutive measurements. The pressure values for the flexion gap were quite consistent, while the pressure values for the extension gap were quite different with an average pressure of 46.3 N in inflection and 35.0 N in extension gaps. Postoperative radiographs showed appropriate prosthesis positioning with good tibial and femoral positioning and flexion angle.When performing pressure measurement, select the sensor corresponding to the size of the prosthesis to avoid damage to the osteotomy surface and affect the flexion-extension gap balance. After gap balancing, install femoral and tibial components in balance. In the future, we need large sample multicenter status to ascertain the acceptable range of the flexion-extension gap pressure difference mirrored by the sensor and its improvement on the long-term effect of UKA.

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Medicine

Making Sense of Listening: The IMAP Test Battery

The ability to hear is only the first step towards making sense of the range of information contained in an auditory signal. Of equal importance are the abilities to extract and use the information encoded in the auditory signal. We refer to these as listening skills (or auditory processing AP). Deficits in these skills are associated with delayed language and literacy development, though the nature of the relevant deficits and their causal connection with these delays is hotly debated.
When a child is referred to a health professional with normal hearing and unexplained difficulties in listening, or associated delays in language or literacy development, they should ideally be assessed with a combination of psychoacoustic (AP) tests, suitable for children and for use in a clinic, together with cognitive tests to measure attention, working memory, IQ, and language skills. Such a detailed examination needs to be relatively short and within the technical capability of any suitably qualified professional. Current tests for the presence of AP deficits tend to be poorly constructed and inadequately validated within the normal population. They have little or no reference to the presenting symptoms of the child, and typically include a linguistic component. Poor performance may thus reflect problems with language rather than with AP. To assist in the assessment of children with listening difficulties, pediatric audiologists need a single, standardized child-appropriate test battery based on the use of language-free stimuli.
We present the IMAP test battery which was developed at the MRC Institute of Hearing Research to supplement tests currently used to investigate cases of suspected AP deficits. IMAP assesses a range of relevant auditory and cognitive skills and takes about one hour to complete. It has been standardized in 1500 normally-hearing children from across the UK, aged 6-11 years. Since its development, it has been successfully used in a number of large scale studies both in the UK and the USA. IMAP provides measures for separating out sensory from cognitive contributions to hearing. It further limits confounds due to procedural effects by presenting tests in a child-friendly game-format. Stimulus-generation, management of test protocols and control of test presentation is mediated by the IHR-STAR software platform. This provides a standardized methodology for a range of applications and ensures replicable procedures across testers. IHR-STAR provides a flexible, user-programmable environment that currently has additional applications for hearing screening, mapping cochlear implant electrodes, and academic research or teaching.

A test battery (IMAP) for performing an in-depth assessment of auditory and cognitive abilities contributing to listening skills is described. It is quick to administer, child-friendly and free from linguistic confounds. Stimulus generation and protocol management are controlled via a software platform (IHR-STAR) to ensure replicable procedures.

The ability to hear is only the first step towards making sense of the range of information contained in an auditory signal. Of equal importance are the ...

Excitotoxic Stimulation of Brain Microslices as an In vitro Model of Stroke

Examining molecular mechanisms involved in neuropathological conditions, such as ischemic stroke, can be difficult when using whole animal systems. As such, primary or &#39;neuronal-like&#39; cell culture systems are commonly utilized. While&#160;these systems are relatively easy to work with, and are useful model systems in which various functional outcomes (such as cell death) can be readily quantified, the examined outcomes and pathways in cultured immature neurons (such as excitotoxicity-mediated cell death pathways) are not necessarily the same as those observed in mature brain, or in intact tissue. Therefore, there is the need to develop models in which cellular mechanisms in mature neural tissue can be examined. We have developed an in vitro technique that can be used to investigate a variety of molecular pathways in intact nervous tissue. The technique described herein utilizes rat cortical tissue, but this technique can be adapted to use tissue from a variety of species (such as mouse, rabbit, guinea pig, and chicken) or brain regions (for example, hippocampus, striatum, etc.). Additionally, a variety of stimulations/treatments can be used (for example, excitotoxic, administration of inhibitors, etc.). In conclusion, the brain slice model described herein can be used to examine a variety of molecular mechanisms involved in excitotoxicity-mediated brain injury.

Excitotoxic Stimulation of Brain Microslices as an In vitro Model of Stroke

We have developed a brain slice model which can be used to examine molecular mechanisms involved in excitotoxicity-mediated brain injury.&#160;This technique generates viable mature brain tissue and reduces animal numbers required for experimentation, whilst keeping the neuronal circuitry, cellular interactions, and postsynaptic compartments partly intact.

Examining molecular mechanisms involved in neuropathological conditions, such as ischemic stroke, can be difficult when using whole animal systems. As ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

Individualized Stem-positioning in Calcar-guided Short-stem Total Hip Arthroplasty

Bone- and soft-tissue sparing short stems are increasingly used in total hip arthroplasty (THA). However, there are a large variety of models of short stems, differing in design and function. Calcar-guided short stems provide an anatomical curvature in the medial calcar region, thus, positioning is done individually alongside the calcar in the "round-the-corner" technique. Depending on the level of the neck's osteotomy, stems can be aligned individually in a large bandwidth of varus- and valgus anatomies. This differs from conventional total hip arthroplasty and potentially includes a severe learning curve. Given that a great variety of caput-collum-diaphyseal (CCD)-angles can be retained, the reconstruction of femoro-acetabular offsets can be achieved precisely. However, particularly extensive varus- and valgus positioning has raised concerns in regard to stability and bone remodeling. The purpose of the present manuscript is to showcase the implantation technique in calcar-guided short-stem THA and to summarize short-term clinical and radiological results.

This protocol describes the round-the-corner technique and the individualized stem-positioning of calcar-guided short stems alongside the medial calcar, depending on the level of the osteotomy. This differs from conventional total hip arthroplasty and includes a learning curve.

Bone- and soft-tissue sparing short stems are increasingly used in total hip arthroplasty (THA). However, there are a large variety of models of short ...

Using a Knee Arthrometer to Evaluate Tissue-specific Contributions to Knee Flexion Contracture in the Rat

Normal knee range of motion (ROM) is critical to well-being and allows one to perform basic activities such as walking, climbing stairs and sitting. Lost ROM is called a joint contracture and results in increased morbidity. Due to the difficulty of reversing established knee contractures, early detection is important, and hence, knowing risk factors for their development is essential. The rat represents a good model with which the effect of an intervention can be studied due to the similarity of rat knee anatomy to that of humans, the rat's ability to tolerate long durations of knee immobilization in flexion, and because mechanical data can be correlated with histologic and biochemical analysis of knee tissue.
Using an automated arthrometer, we demonstrate a validated, precise, reproducible, user-independent method of measuring the extension ROM of the rat knee joint at specific torques. This arthrometer can be used to determine the effects of interventions on knee joint ROM in the rat.

The goal of the protocol is to measure the extension range of motion of the rat knee. The effects of various diseases that increase the stiffness of the knee joint and the effectiveness of treatments can be quantified.

Normal knee range of motion (ROM) is critical to well-being and allows one to perform basic activities such as walking, climbing stairs and sitting. Lost ...

A Rat Carotid Artery Pressure-Controlled Segmental Balloon Injury with Periadventitial Therapeutic Application

Cardiovascular disease remains the leading cause of death and disability worldwide, in part due to atherosclerosis. Atherosclerotic plaque narrows the luminal surface area in arteries thereby reducing adequate blood flow to organs and distal tissues. Clinically, revascularization procedures such as balloon angioplasty with or without stent placement aim to restore blood flow. Although these procedures reestablish blood flow by reducing plaque burden, they damage the vessel wall, which initiates the arterial healing response. The prolonged healing response causes arterial restenosis, or re-narrowing, ultimately limiting the long-term success of these revascularization procedures. Therefore, preclinical animal models are integral for analyzing the pathophysiological mechanisms driving restenosis, and provide the opportunity to test novel therapeutic strategies. Murine models are cheaper and easier to operate on than large animal models. Balloon or wire injury are the two commonly accepted injury modalities used in murine models. Balloon injury models in particular mimic the clinical angioplasty procedure and cause adequate damage to the artery for the development of restenosis. Herein we describe the surgical details for performing and histologically analyzing the modified, pressure-controlled rat carotid artery balloon injury model. Additionally, this protocol highlights how local periadventitial application of therapeutics can be used to inhibit neointimal hyperplasia. Lastly, we present light sheet fluorescence microscopy as a novel approach for imaging and visualizing the arterial injury in three-dimensions.

The rat carotid artery balloon injury mimics the clinical angioplasty procedure performed to restore blood flow in atherosclerotic vessels. This model induces the arterial injury response by distending the arterial wall, and denuding the intimal layer of endothelial cells, ultimately causing remodeling and an intimal hyperplastic response.

Cardiovascular disease remains the leading cause of death and disability worldwide, in part due to atherosclerosis. Atherosclerotic plaque narrows the ...

Using a Chemical Biopsy for Graft Quality Assessment

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated with an increased survival rate and greater quality of patient&#8217;s life when compared to conventional dialysis. Regrettably, transplantology suffers from a lack of reliable methods for organ quality assessment. Standard diagnostic techniques are limited to macroscopic appearance inspection or invasive tissue biopsy, which do not provide comprehensive information about the graft. The proposed protocol aims to introduce solid phase microextraction (SPME) as an ideal analytical method for comprehensive metabolomics and lipidomic analysis of all low molecular compounds present in kidneys allocated for transplantation. The small size of the SPME probe enables performance of a chemical biopsy, which enables extraction of metabolites directly from the organ without any tissue collection. The minimum invasiveness of the method permits execution of multiple analyses over time: directly after organ harvesting, during its preservation, and immediately after revascularization at the recipient&#8217;s body. It is hypothesized that the combination of this novel sampling method with a high-resolution mass spectrometer will allow for discrimination of a set of characteristic compounds that could serve as biological markers of graft quality and indicators of possible development of organ dysfunction.

The protocol presents utilization of the chemical biopsy approach followed by comprehensive metabolomic and lipidomic analysis for quality assessment of kidney grafts allocated for transplantation.

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated ...

Application of Lucilia sericata Larvae in Debridement of Pressure Wounds in Outpatient Settings

Biological therapy using Lucilia sericata larvae has numerous advocates worldwide, yet it is still fairly unknown and not commonly applied in daily practice because of the limited awareness and insufficient experience of medical and nursing personnel. There are case reports suggesting that maggot therapy can be applied and supported by lay caregivers, provided they are supervised and informed by physicians/nurses. The foregoing observation suggests that the method should be considered for implementation by a wider group of caregivers if accepted and meticulously supervised by trained and experienced medical staff. The concerns related to the therapeutic use of maggots in certain regions seem understandable, but are not supported by scientific facts. It should be noted that many therapeutic agents (including brood) used in medicine are of natural origin, and are associated with low production costs and high possibilities of implementation in the course of therapy. By analyzing the literature and using our own clinical and research experience, we have come to conclusions related to using larvae therapy, as a quick and safe method providing cleaning and revitalization in the process of treating wounds of various etiologies, especially pressure ulcers. In the current study, medical-grade Lucilia sericata maggots were applied to remove necrotic tissue from deep pressure sores. The treatment is mostly accepted by both caregivers and patients. In most cases, it is conducted by trained and experienced medical personnel in home and outpatient settings. Over the course of the conducted analyzes involving the collected specimens, there were no statistically significant relationships (p&gt; 0.05) confirmed between the wound surface successfully cleared by brood and variables, such as time from wound formation, location, surface size, and the depth of damage to the tissue structure. The lack of statistical dependence may result from the small size of the studied group. Based on the current findings, we have formulated the following conclusions: Maggot Debridement Therapy (MDT) is a fast and effective method enabling the preparation of the wound bed. The use of MDT in outpatient settings is safe and acceptable for patients and their caregivers.

Application of Lucilia sericata Larvae in Debridement of Pressure Wounds in Outpatient Settings

Maggots of Lucilia sericata were used in the debridement of deep pressure sores in outpatient settings for the treatment of pressure sores involving the complete skin thickness. The technique presented in the article does not pose risks for the patient.

Biological therapy using Lucilia sericata larvae has numerous advocates worldwide, yet it is still fairly unknown and not commonly applied in daily ...

Knee Arthrocentesis in Adults

Arthrocentesis of the knee is a procedure in which a needle is inserted into the knee joint, and synovial fluid is aspirated. An arthrocentesis can be diagnostic or therapeutic. Synovial fluid may be removed for testing to determine the nature of the knee effusion. If septic arthritis is suspected, urgent arthrocentesis before initiation of antibiotic treatment is indicated. Moreover, arthrocentesis can also aid in diagnosing crystal-induced arthritis such as gout or pseudogout, or non-inflammatory arthritis such as osteoarthritis. Identifying the cause of the knee effusion can guide treatment. Furthermore, removing fluid from a knee can reduce intraarticular pressure to decrease pain and improve range of motion. There is no absolute contraindication to performing this procedure, but in selecting the needle entry site, an area of skin that is infected should be avoided. Therefore, caution should be exercised when a patient presents with suspected cellulitis over the knee joint to avoid the potential risk of causing iatrogenic septic arthritis. A knee that has undergone arthroplasty should be assessed for arthrocentesis by an orthopedic surgeon. Arthrocentesis of the knee is typically performed with the patient supine. The site for needle insertion is marked, and then the skin is disinfected. After a local anesthetic is administered, a needle is inserted along the pathway that was anesthetized. Synovial fluid is aspirated, and then the needle is withdrawn. Pressure is applied until any bleeding stops. The synovial fluid can be analyzed for infection and inflammation but cannot directly confirm a diagnosis of internal derangement or autoimmune causes of arthritis. In addition to the history and physical examination, laboratory findings and imaging can clarify the etiology of a knee effusion.

Here the protocol describes arthrocentesis of the knee, a procedure in which a needle is inserted into the knee joint, and synovial fluid is aspirated. Synovial fluid may be removed for testing to determine the nature of the knee effusion. Arthrocentesis of the knee is typically performed with the patient supine.

Arthrocentesis of the knee is a procedure in which a needle is inserted into the knee joint, and synovial fluid is aspirated. An arthrocentesis can be ...

The Use of Mixed Reality in Custom-Made Revision Hip Arthroplasty: A First Case Report

The technology of 3D printing and visualization of anatomical structures is rapidly growing in various fields of medicine. A custom-made implant and mixed reality were used to perform complex revision hip arthroplasty in January 2019. The use of mixed reality allowed for a very good visualization of the structures and resulted in precise implant fixation. According to the authors' knowledge, this is the first described case report of the combined use of these two innovations. The diagnosis preceding the qualification for the procedure was the loosening of the left hip's acetabular component. Mixed reality headset and holograms prepared by engineers were used during the surgery. The operation was successful, and it was followed by early verticalization and patient rehabilitation. The team sees opportunities for technology development in joint arthroplasty, trauma, and orthopedic oncology.

A complex revision hip arthroplasty was performed using a custom-made implant and mixed reality technology. According to the authors&#39; knowledge, this is the first report of such procedure described in the literature.

The technology of 3D printing and visualization of anatomical structures is rapidly growing in various fields of medicine. A custom-made implant and mixed ...