Name: the use of mixed reality in custom-made revision hip arthroplasty: a first case report
Uploaded: 2022-08-04T12:45:00.000+00:00
Duration: 7 min 45 s
Description: Watch this Scientific Journal Video about The Use of Mixed Reality in Custom-Made Revision Hip Arthroplasty: A First Case Report at JoVE.com

Not applicable.
The study was carried out as part of a non-commercial cooperation.

The protocol follows guidelines of the Human Research Ethics Committee of the Medical University of Warsaw. The patient gave informed consent to the procedure and acknowledged the fact that it will be recorded. The patient agreed to that prior to the procedure.
NOTE: The basic criterion for including the patient in the surgery project was the necessity to intervene because of the anatomical dysfunction, which made it impossible to use a standard implant. Mixed reality was aimed at better placement of the prosthesis, increasing the chances of successful surgery.
1. Preparation
<ol>
	<li>Prepare a custom-made acetabular implant and plan the surgical procedure before the patient&#39;s hospitalization. 
	NOTE: In this case study, persons skilled in the art of medical image diagnostics prepared the custom-made acetabular implant.
	<ol>
		<li>Before the planned admission to the hospital, perform an x-ray in the diagnostic imaging unit.</li>
		<li>Perform a pelvic X-ray in an anterior-posterior projection.</li>
		<li>Assess the current condition of the patient&#39;s pelvis based on the X-ray.</li>
		<li>Compare the image obtained with the earlier X-ray images.</li>
	</ol>
	</li>
	<li>Take a pelvic CT scan and acquire DICOM (Digital Imaging and Communications in Medicine) files according to the protocol.
	<ol>
		<li>Place the patient on the moveable CT scan platform.</li>
		<li>Click on the thickness button and select 512 x 512 px thickness for the scans.</li>
		<li>Click on the parameter that determines the thickness of the 1 mm layer.</li>
		<li>Start the procedure by clicking, wait for the test result.</li>
	</ol>
	</li>
	<li>Ask an engineer to design an implant proposal that can be sent digitally as a technical scheme, or a 3D printed model prototype (Figure 1).
	<ol>
		<li>Visualize the computed tomography result in the DICOM viewer.</li>
		<li>Determine the needs for the implementation of the implant, taking into account the current anatomical conditions of the patient, biomechanics, and the function of the joint.</li>
		<li>Consult the engineer for suggestions on implants, including fixation.</li>
		<li>Approve the project and wait for shipment. 
		NOTE: The final shape of the implant involves combining 3D data from a patient&#39;s CT scan with the input of a design engineer and a surgeon.</li>
	</ol>
	</li>
	<li>Print the custom-made 3D implant from the titanium alloy powder (TiAl6V4) using electron beam technology26,27. Inside a chamber containing small amounts of TiAl6V4 powder, each time the electron beam is fired, there is selective melting and accumulation of material (plasma coating).</li>
	<li>Check whether the implant was sterilized. Sterilization of implant trials and the final implant was guaranteed by the manufacturer.</li>
</ol>
2. Pre-surgery checkups
<ol>
	<li>Perform a standard of care laboratory tests and specialist consultations.
	<ol>
		<li>Exclude patients with potential periprosthetic joint infection (no radiological features, normal c-reactive protein (&#60;10 mg/L), and erythrocyte sedimentation rate of 1-10 mm/h for women, 3-15 mm/h for men).</li>
	</ol>
	</li>
	<li>Check for the clinical signs of infection such as fever (systemic), pain, swelling, redness (local), and reduced joint function28.
	<ol>
		<li>Exclude patients having signs of local inflammation during the clinical examinations (redness, temperature increase, pain, swelling and loss of function indicate local inflammation). The patient gave complete informed consent to the operation.</li>
	</ol>
	</li>
</ol>
3. Mixed reality model
NOTE: The process is performed to achieve proper implant and pelvis visualization, which will be used intraoperatively.
<ol>
	<li>Process the pelvic CT DICOM file into a holographic representation using dedicated application.
	<ol>
		<li>Load the CT image into mixed reality headset from acquired CT DICOM files.
		<ol>
			<li>Open holographic DICOM Viewer.</li>
			<li>Select the folder containing CT DICOM files.</li>
			<li>Check the IP that is displayed when the headset is switched on and enter it in a designated place in the holographic DICOM Viewer.</li>
			<li>Click on the Connect button to be able to see the visualization in the mixed reality headset.</li>
		</ol>
		</li>
		<li>Segment the pelvis bone tissue structures. This is performed manually by using the Scissors option. When the option is enabled, the user clicks the left mouse button and moves the mouse around to remove the structures that are selected with this tool.
		<ol>
			<li>End the selection with another click of the left mouse button, which creates a pop-up for the user to confirm that he/she wants to cut out the structures that are selected. 
			NOTE: The user can choose areas to be cut out from the visualization in both 3D and 2D views. It is possible to remove the structures from within or outside the selection. This is repeated until only the necessary parts of the CT image are visible.</li>
		</ol>
		</li>
		<li>Choose a predefined transfer function (color visualization parameters) dedicated to orthopedic procedures from the list of available functions by clicking on its name: CT Bone Endoprosthesis. If needed, adjust the visualization by changing the window and level using the right mouse button connected with mouse movement in the 3D visualization window.</li>
		<li>Connect to the headset to see the prepared visualization in the 3D holographic space. Adjust the image using voice commands: Rotate, Zoom, Cut Smart, and Hand Gestures.</li>
		<li>Use the Cut Smart command to use and adjust a cutting plane that is perpendicular to user&#39;s line of sight. The closer the user moves the head into the hologram, the deeper the plane goes.</li>
		<li>Perform these movements to see the inner parts of the visualization because structures that are located anteriorly to the plane are not visualized. 
		NOTE: This view is important to assess the geometrical relations between structures (pelvis, femur, and implant) (Figure 2 and Figure 3).</li>
	</ol>
	</li>
</ol>
4. Surgery
<ol>
	<li>Perform the surgical procedure of revision hip arthroplasty due to aseptic loosening of the acetabular component with the use of a custom-made acetabular implant and mixed reality device14,16,29. Use a scalpel, an electrosurgical knife with a coagulator, a Luer tool and cutters for the operation.
	<ol>
		<li>Give 1.5 g of ceftriaxone intravenously 30 min prior to the skin incision, and two subsequent doses are to be given on the day of the surgery to prevent infection. Initiate thromboprophylaxis on the day before the surgery with low molecular weight heparin (LMWH). Continue the single daily dose of 40 mg enoxaparin for 30 days after the procedure.</li>
		<li>Place and secure the patient under general anesthesia, lying down on the operating table.</li>
		<li>Release the connective tissue adhesions using the Hardinge access to the hip joint and remove the loose acetabular implant.</li>
		<li>Perform the operation in the same way as other revision procedures of the hip joint, but use a wider access.</li>
		<li>Remove all soft tissues from the surface of the acetabulum so that the shape is exactly the same as in the model provided. The implant model must perfectly adhere to the surface of the acetabular bone.</li>
		<li>Fix the new uncemented implant using specially designed screws that stabilize the implant.</li>
		<li>Perform a femoral nerve block after surgery.</li>
	</ol>
	</li>
	<li>Intraoperative holographic visualization of processed images
	<ol>
		<li>Load the visualization of the DICOM CT scan prepared in the pre-procedural planning to the mixed reality application.</li>
		<li>Connect the mixed reality headset to the mixed reality application to see the prepared visualization in the 3D holographic space.</li>
		<li>Use intraoperative holographic visualization of the processed images to achieve adequate and precise pelvic bone surface preparation as well as for removal of the excess of connective tissue that developed as a response to loosening of the acetabular component.</li>
		<li>Ensure that the operator looks at the holographic visualization as a reference image.</li>
		<li>Use a scalpel, an electrosurgical knife with a coagulator, a luer tool, and cutters for the operation. Visualization of the 3D pelvis model should minimize the risk of damaging neurovascular structures and mistakes in implant placement.</li>
		<li>Ensure that the head-mounted display is connected to the workstation through a WiFi network. The processing of the images and the rendering is performed on the workstation and the results are displayed on the headset as holograms. Use gestures and voice commands. If necessary, get help from an engineer with POV preview.</li>
	</ol>
	</li>
</ol>
5. Postoperative care
<ol>
	<li>Make the patient undergo a standard rehabilitation and recovery protocol, including rehabilitation and mobilization on the first day after surgery30,31,32. 
	NOTE: Rehabilitation was implemented by a dedicated team experienced in the hip and knee arthroplasty.</li>
	<li>Implement pharmacological thromboprophylaxis. Thromboprophylaxis was initiated on the day before the surgery with low molecular weight heparin (LMWH). The single daily dose of 40 mg enoxaparin was continued for 30 days after the procedure.</li>
</ol>

Maciej Stanuch, Adriana Z&#322;ahoda-Huzior and Andrzej Skalski are MedApp S.A. employees. MedApp S.A. is the company that manufactures the CarnaLifeHolo solution.

Primary and revision hip arthroplasty may require personalization to ensure effectiveness of treatment. However, the use of custom implants requires longer preparation for surgery compared to standard procedures. Custom-made 3D printed implants are the solution that gives a chance to restore function in non-typical patients whose disease has caused significant bone destruction29. Standard prostheses are insufficient due to advanced degenerative disease developing rapidly, bone defects caused by primary bone tumors or metastases, as well as complicated injuries or multiple revision procedures16. Custom-made implants are prepared for a specific patient with complete individualization considering anatomical anomalies and current clinical condition. The process of creating an implant requires the cooperation of orthopedic surgeons with engineers and is based on CT or magnetic resonance imaging (MRI). The preparation of the virtual implant model is complicated. It is performed by engineers who precisely determine the forces acting between the bone and the implant. The preliminary virtual 3D model is consulted with the surgeon and, after its approval, the production of the custom-made implant begins. The correct implant is delivered along with PDF file instructions for the operating team. It is accompanied by a precise plastic model of the pelvic bones and implant for training purposes and intraoperative fitting.
Preoperative planning is of great importance, especially in the context of revision arthroplasty. When qualifying a patient for the procedure, it is necessary to take into account their general clinical condition, the burden of comorbidities, and the current history of the disease15. After the team leader makes the decision, the results of computer tomography are sent to the manufacturer of the implant, and then the 6-week-long procedure begins, which includes producing a 3D model and the final version of the implant.
Mixed reality is a hybrid of real and virtual reality in which physical objects coexist with digital holograms, and interaction between them is possible in real-time21. It is now widely used in various fields, including medicine35,36,37, and it is most often used to visualize medical data such as three-dimensional CT scans or MRI38,39,40. This technology makes it possible to plan treatments more precisely, quickly access patient&#39;s data in diagnostics, or better visualize the surgical field intraoperatively41. Mixed reality has also found its application in education in basic and clinical sciences at every stage of training, including students, medical residents, and consultants.
As in the case of preparation of custom-made implants, the first stage of cooperation between doctors and engineers is medical imaging data stored in the DICOM standard. More advanced techniques used in radiology and simultaneously developing technological solutions also allow for the integration and usability of dynamic imaging data, e.g., real-time ultrasound. The next stage is rendering-processing the obtained data to make three-dimensional holograms sent to a device. The user can see the visualization as a part of his surroundings and can interact with it easily. The headset placed on the head of the operator or members of the operational team are equipped with sensors (cameras, accelerometer, magnetometer, gyroscope), allowing the holographic data to be seen as a part of the surroundings (Figure 12). The operator can control the holograms with hand gestures and voice commands, which adjust the visualization to his/her specific needs. It is possible to change size, structure, position with maintained sterile conditions. The HoloLens does not adversely affect work comfort and does not limit the field of view during the procedure when the holograms are not displayed. The medical team was previously prepared for the operation through the possibility of getting acquainted with the precise and detailed 3D printing joint and prosthesis models delivered together with the implant, as well as through training with a team of engineers. The use of mixed reality glasses is very intuitive, and the efficient use of uploaded holograms is easy to learn. The mixed reality was an effective solution, both in terms of preparation for the operation and in terms of the conduct of the procedure.
According to authors&#39; knowledge, this is the first report on the use of mixed reality technology in hip revision surgery with the use of the 3D printed acetabular implant. It was the first intraoperative use of the device in the authors&#39; clinical center (Figure 13). Previous publications include primary hip arthroplasty with the use of mixed reality technology. It was presented by Lei Peng-fei et al. in a 59-year-old patient with intertrochanteric fracture42. Custom-made implants and mixed reality are an increasingly popular solution used in different areas of surgery. The combination of both is an innovation with promising results. Currently, these types of treatments are experimental due to high costs and the need for appropriate preparation, there is not enough quantity to create objective original studies; however, in the near future, it will be possible due to the research grants and growing interest of clinicians. In the context of the existing and commonly used solutions during surgical procedures, X-ray or CT projections displayed on a standard 2D monitor have limitations because they do not allow viewing anatomical structures from a different perspective. It is not possible to enlarge and change the position of the structure in space. In the authors&#39; opinion, custom-made implants and mixed reality technology is promising for difficult revision arthroplasty, as well as traumatology and orthopedic oncology. According to the authors, the mixed reality is also applicable for patients qualified for standard endoprostheses, including primary endoprostheses that do not require custom-made implants. Intraoperative navigation augmented by mixed reality allows for better and more precise placement of implants. Pilot studies are currently being carried out with promising results43.
Each stage of planning the procedure and preparing the patient is very important and none of them can be underestimated. The quality of medical imaging and the appropriate cooperation with engineers, both in the design of the implant and in the preparation of the hologram, are important for the success of the surgery. The critical moment during the procedure is the removal of the old implant components and the fixing of the new, personalized one in a previously prepared place. At this stage, holograms are important for the procedure to be performed very precisely.

The technology of three-dimensional (3D) printing and visualization of complex structures is rapidly growing in various fields of medicine. These include cardiovascular surgery, otorhinolaryngology, maxillofacial surgery, and, above all, orthopedic surgery1,2,3,4,5. Currently, this technology is used in orthopedic surgery not only in the direct implementation of 3D printed elements, but also in surgical training, preoperative planning, or intraoperative navigation6,7,8.
Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are one of the most frequently performed orthopedic surgical procedures worldwide. Due to the significant improvement in the patient&#39;s quality of life, THA had been described in a previous publication as the &#34;surgery of the century&#34;9. In Poland, 49.937 THA and 30.615 TKA were performed in 201910. As life expectancy increases, there is an upward trend in the projected number of hip and knee arthroplasty surgeries. Great efforts have been made to improve implant design, surgical technique, and postoperative care. These advances led to a better chance of restoring patient function and reducing the risk of complications11,12,13,14.
However, the big challenge currently faced by orthopedic surgeons worldwide is working with non-standard patients whose anatomical defects in the hip joint make it very difficult or even impossible to implement an off-the-shelf implant15. Bone loss may be due to significant trauma, progressive degenerative osteoarthritis with an acetabular protrusion, developmental hip dysplasia, primary bone cancer, or metastasis16,17,18,19,20. The problem of implant selection specifically concerns patients who are at risk of multiple revisions, sometimes also requiring unconventional treatment. In such cases, a very promising solution is an additive-made 3D printed implant created for a specific patient and bone defect, allowing for a very precise anatomical fit20.
In the field of arthroplasty, precise implant and its sustainable fixation are crucial. Progress in preoperative and intraoperative 3D visualization has resulted in excellent solutions as augmented and mixed reality21,22,23,24. Intraoperative use of bone and implant computed tomography (CT) holograms may allow better prosthesis placement than conventional radiography images. This emerging technology may increase the chances of therapy effectiveness and reduce the risk of neurovascular complications21,25.
This case report concerns a patient subjected to hip revision surgery due to aseptic loosening. To address significant bone loss caused by multiple implant failures, the custom-made 3D printed acetabular implant was used. During the procedure, we used mixed reality to visualize the implant position to avoid damaging the at-risk neurovascular structures. Application implemented to mixed reality headset allows giving voice and gesture commands, making it possible to use it in sterile conditions during the surgical procedure.
A 57-year-old woman was admitted to the department with a preliminary diagnosis: loosening of the left hip&#39;s acetabular component. The patient&#39;s disease history was extensive. Throughout her life, she underwent numerous surgical procedures of the hip joint. The first treatment was hip resurfacing due to osteoarthritis caused by hip dysplasia (1977-15 years old), the second was a total hip arthroplasty due to implant loosening (1983-21 years old), and other two revision surgeries (1998, 2000-37 and 39 years old). Moreover, the patient was suffering from spastic left-sided hemiplegia caused by childhood cerebral palsy, and she was repeatedly operated due to left clubfoot deformity. She was also burdened with osteoarthritis of the thoracolumbar spine, carpal tunnel syndrome, and well-controlled arterial hypertension. The final diagnosis preceding the qualification for the next procedure was the pain and increasing function limitation caused by loosening of the left hip&#39;s acetabular component. The patient was highly motivated, physically active, and coping with disability.

<table><tbody><tr><td>CarnaLifeHolo v. 1.5.2</td><td>MedApp S.A.</td><td></td><td></td></tr><tr><td>Custom-Made implant type Triflanged Acetabular Component</td><td>BIOMET</td><td>REF PM0001779</td><td></td></tr><tr><td>Head Constrained Modular Head + 9mm Neck for cone 12/14, Co-Cr-Mo, size 36mm</td><td>BIOMET</td><td>REF 14-107021</td><td></td></tr><tr><td>Polyethylene insert Freedom Ringloc-X Costrained Linear Ringloc-X 58mm for head 36mm / 10 *</td><td>BIOMET</td><td>REF 11-263658</td><td></td></tr></tbody></table>

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.

Image preprocessing 
Binary masks of the pelvic bone, femur, and endoprosthesis were semi-automatically segmented from CT DICOM images by experienced radiologic technologists using thresholding and region growing algorithms with available software33. The prepared label maps were also manually corrected by a radiologist. Label maps were used to enhance the visualization by adding them to the CT scan in the next step. This approach made it possible to merge the volumetric rendering, which allows to see the bone structure and surrounding tissues on the CT scans, with the segmented parts indicating important tissues. The segmentation results were concluded in the original stack, which avoided constructing only a 3D graphical model of structures but made it possible to maintain information about all Hounsfield Units (HU) values. It resulted in an interactive visualization that allowed one to display tissues, implant and conduct bone segmentations simultaneously or one at a time, depending on the surgical situation (Figure 1 and Figure 4) visualizations of the fixed implant. The processed CT data set was visualized as holograms using dedicated software.
Pre-procedural planning and hospitalization 
On the basis of computer tomography data and visualizations, an operation plan was prepared. The plan included important values: hip center of rotation, acetabular inclination, anteversion, and the direction, method and zones of implant mounting. The position of the implant was determined by bone and anatomical points, while the appropriate configuration was additionally confirmed after setting the trial head of the prosthesis and clinical checking of the implant&#39;s stability during the procedure. Post-operative CT was performed in order to confirm the correct position of the implant. The position of the screws was planned on the basis of the CT by the engineer and surgeon, which allowed to avoid contact of the screws with the vascular-nerve structures and their damage (Figure 5). The acetabular defect was classified as 3B Paprosky classification34. Type 3B is the most severe destruction of all acetabular structures, including walls and columns34. The clinical HHS score before surgery was 44 (Table 1).
Activities to prepare the patient for the procedure included internal medicine consultation and standard laboratory tests. Essential examinations were also necessary: ECG and X-ray: chest X-ray, pelvic X-ray. The control image was also taken after surgery. The patient received standard thromboprophylaxis (Clexane 40 mg, 1 x 1 s.c.) and antibiotic prophylaxis (Tarsime 3 x 1.5 g i.v.) during hospitalization. Individualized pain therapy was included. All other medications were taken according to the patient&#39;s standard recommendations.
In January 2019, an arthroplasty revision of the left hip was performed, which included the replacement of a loose acetabular component with the custom-made implant: Triflanged acetabular component, Polyethylene insert, constrained, Fastening screws-10 pieces, Co-Cr-Mo constrained modular head (36 mm), and a 9 mm neck.
The operation lasted for 4 h and was executed without complications. Verticalization with the help of a walker took place on the second day after the procedure. The patient was discharged on day 14 in a good general condition (long rehabilitation time due to foot paralysis after cerebral palsy). Control visits took place following the appointed dates. Radiological control-CTs and X-rays were performed before the surgery (Figure 3, Figure 6, and Figure 7), after the surgery (Figure 2 and Figure 8) and after 2 years (Figure 9). Implant placement was performed in accordance with the assumptions of the project. The offset, range of motion, and length of the limbs were restored. The function and patient&#39;s quality of life were relatively good on the subsequent visit and improved significantly since the initial diagnosis. Before the operation, the patient moved to a wheelchair because of pain-the patient&#39;s subjective assessment on the 10-point visual analog pain-intensity scale was 8 (VAS 8). After surgery, during rehabilitation, she stopped using two orthopedic crutches. The patient currently walks with one crutch due to foot drop-peroneal nerve palsy after previous surgery in another hospital. According to the authors&#39; knowledge, it was the first such procedure in Poland and one of the first in the world. It was a medical student research team that proposed the idea of using modern technology in the Department of Orthopedics and Traumatology of the Musculoskeletal System.
Anatomical structures that require surgical intervention must be visible for adequate implant fixation as planned. In the case of non-standard patients with significant bone defects and deformation, the appropriate visualization and adjustment of a custom-made prosthesis are of fundamental importance for the treatment process. Proper implant fixation reduces the risk of postoperative complications such as loosening or instability. The technology of mixed reality allows without risk and in a non-invasive way to accurately visualize the pelvis, bones, and soft tissues, increasing the chances of good implant placement and even possibly shortening the time of surgery in the future. The ability to manipulate the image, for example, zooming in the selected fragments of the complex anatomical structures, allows excluding the imperfections of the surgeon&#39;s eye (Figure 10 and Figure 11). In summary, a precise, fully personalized complex revision arthroplasty was performed. The authors see opportunities for the further development of mixed reality in orthopedics, not only in arthroplasty and traumatology, but also in orthopedic oncology, where it is often necessary to perform very extensive resections with a high level of precision. The appropriate visualization of difficult-to-access anatomical areas with surrounding neurovascular structures can make surgery easier for the surgeon and safer for the patient.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/63654/63654fig01.jpg" /> 
Figure 1: Visualization of the fixed implant. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/63654/63654fig02.jpg" /> 
Figure 2: X-ray one day after the surgery. The letter &#39;L&#39; represents the left side of the body on the X-ray. In this case, a photo of the left hip. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/63654/63654fig03.jpg" /> 
Figure 3: X-ray before the surgery. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/63654/63654fig04.jpg" /> 
Figure 4: Visualization of the fixed implant. Visualization is prepared in the process of preoperative planning. It shows the potential fixation of the implant. The blue color in the visualization is the border of the implant. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/63654/63654fig05.jpg" /> 
Figure 5: 3D project for insertion of implant fixing screws. Colors are used by engineers for better and more accurate visualization. This makes it easy to distinguish bolts having different parameters-length, cross-section. The mounting sequence can also be taken into account. The colors are illustrative and are used in the pre-operative planning process. In the process of planning the implant mounting, it is important to exclude intraoperative damage to blood vessels and nerves. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig05large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/63654/63654fig06.jpg" /> 
Figure 6: CT-3D reconstruction before the surgery shows the hip joints and part of the femur. Visible degeneration and destruction of bone structures, pelvic asymmetry. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig06large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/63654/63654fig07.jpg" /> 
Figure 7: CT-3D reconstruction before the surgery. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig07large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/63654/63654fig08.jpg" /> 
Figure 8: X-ray 6 weeks after the surgery. The implant was fitted correctly, it did not come loose. Visible left hip endoprosthesis with fixing elements. X-ray in combination with the clinical examination of the patient confirms the success of the operation. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig08large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 9" class="xfigimg" src="/files/ftp_upload/63654/63654fig09.jpg" /> 
Figure 9: X-ray 2 years after the surgery. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig09large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 10" class="xfigimg" src="/files/ftp_upload/63654/63654fig10.jpg" /> 
Figure 10: Mixed reality user&#39;s point of view - pelvis from the front. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig10large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 11" class="xfigimg" src="/files/ftp_upload/63654/63654fig11.jpg" /> 
Figure 11: Mixed reality user&#39;s point of view - pelvis from the side. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig11large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 12" class="xfigimg" src="/files/ftp_upload/63654/63654fig12.jpg" /> 
Figure 12: Mixed reality user&#39;s point of view - the photo taken during the surgery - the hologram shows a part of the pelvis. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig12large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 13" class="xfigimg" src="/files/ftp_upload/63654/63654fig13.jpg" /> 
Figure 13: The photo taken during the surgery - main operator, Prof. &#321;&#281;gosz uses mixed reality technology. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63654/63654fig13large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td colspan="4">HSS SCORE</td>
		</tr>
		<tr>
			<td>BEFORE SURGERY</td>
			<td>6 WEEKS AFTER SURGERY</td>
			<td>6 MONTH AFTER SURGERY</td>
			<td>12 MONTH AFTER SURGERY</td>
		</tr>
		<tr>
			<td>44</td>
			<td>74,5</td>
			<td>80</td>
			<td>82</td>
		</tr>
	</tbody>
</table>
Table 1: HHS Score table - presenting the patient&#39;s results according to the Harris Hip score before the procedure, 6 weeks after the procedure, 6 months after the procedure, 12 months after the procedure.

Watch this Scientific Journal Video about The Use of Mixed Reality in Custom-Made Revision Hip Arthroplasty: A First Case Report at JoVE.com

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

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 ...

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Nanyang Technological University

Research

JoVE Journal

Medicine

3.3K Views.  Medical University of Warsaw. A complex revision hip arthroplasty was performed using a custom-made implant and mixed reality technology. According to the authors' knowledge, this is the first report of such procedure described in the literature. 

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

A Teleoperated Robotic System-Assisted Percutaneous Transiliac-Transsacral Screw Fixation Technique

Transiliac-transsacral screw fixation is challenging in clinical practice as the screws need to break through six layers of cortical bone. Transiliac-transsacral screws provide a longer lever arm to withstand the perpendicular vertical shear forces. However, the screw channel is so long that a minor discrepancy can lead to iatrogenic neurovascular injuries. The development of medical robots has improved the precision of surgery. The present protocol describes how to use a new teleoperated robotic system to execute transiliac-transacral screw fixation. The Robot was operated remotely to position the entry point and adjust the orientation of the sleeve. The screw positions were evaluated using postoperative computed tomography (CT). All the screws were safely implanted, as confirmed using intraoperative fluoroscopy. Postoperative CT confirmed that all the screws were in the cancellous bone. This system combines the doctor's initiative with the Robot's stability. The remote control of this procedure is possible. Robot-assisted surgery has a higher position-retention capacity compared with conventional methods. In contrast to active robotic systems, surgeons have full control over the operation. The robot system is fully compatible with operating room systems and does not require additional equipment.

Teleoperated robotic system-assisted percutaneous transiliac-transsacral screw fixation is a feasible technique. Screw channels can be implemented with high accuracy owing to the excellent freedom of movement and stability of the robotic arms.

Transiliac-transsacral screw fixation is challenging in clinical practice as the screws need to break through six layers of cortical bone. ...

Engineering

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 ...

Combining Augmented Reality and 3D Printing to Display Patient Models on a Smartphone

Augmented reality (AR) has great potential in education, training, and surgical guidance in the medical field. Its combination with three-dimensional (3D) printing (3DP) opens new possibilities in clinical applications. Although these technologies have grown exponentially in recent years, their adoption by physicians is still limited, since they require extensive knowledge of engineering and software development. Therefore, the purpose of this protocol is to describe a step-by-step methodology enabling inexperienced users to create a smartphone app, which combines AR and 3DP for the visualization of anatomical 3D models of patients with a 3D-printed reference marker. The protocol describes how to create 3D virtual models of a patient&rsquo;s anatomy derived from 3D medical images. It then explains how to perform positioning of the 3D models with respect to marker references. Also provided are instructions for how to 3D print the required tools and models. Finally, steps to deploy the app are provided. The protocol is based on free and multi-platform software and can be applied to any medical imaging modality or patient. An alternative approach is described to provide automatic registration between a 3D-printed model created from a patient&rsquo;s anatomy and the projected holograms. As an example, a clinical case of a patient suffering from distal leg sarcoma is provided to illustrate the methodology. It is expected that this protocol will accelerate the adoption of AR and 3DP technologies by medical professionals.

Presented here is a method to design an augmented reality smartphone application for the visualization of anatomical three-dimensional models of patients using a 3D-printed reference marker.

Augmented reality (AR) has great potential in education, training, and surgical guidance in the medical field. Its combination with three-dimensional (3D) ...

A Probing Device for Quantitatively Measuring the Mechanical Properties of Soft Tissues during Arthroscopy

Probing in arthroscopic surgery is performed by pulling or pushing the soft tissue, which provides feedback for understanding the condition of the soft tissue. However, the output is only qualitative based on the &#8220;surgeon&#8217;s feeling&#8221;. Herein is described a probing device developed to address this issue by measuring the resistance of soft tissues quantitatively with a tri-axial force sensor. Under both conditions (i.e., pull- and push-probing certain tissues mimicking the acetabular labrum and cartilage), this probing device is found to be useful for measuring some mechanical properties in joints during arthroscopy.

Probing during arthroscopy surgery is normally done to assess the condition of the soft tissue, but this approach has always been subjective and qualitative. This report describes a probing device that can measure the resistance of the soft tissue quantitatively with a tri-axial force sensor during arthroscopy.

Probing in arthroscopic surgery is performed by pulling or pushing the soft tissue, which provides feedback for understanding the condition of the soft ...

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

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

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

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

The Transition to an Anterior-Based Muscle Sparing Approach Improves Early Postoperative Function but is Associated with a Learning Curve

Surgeons considering transitioning to an anterior-based approach for THA are concerned about the learning curve and the reported marginal clinical benefit. Accordingly, the first cohort of THAs, which were implanted by a single surgeon using the anterior-based muscle-sparing approach (ABMS), was analyzed. The goal of the study was to test 1) whether patient-reported outcomes improved and 2) whether the complication rate decreased with the number of THAs performed. A retrospective cohort study on the first 30 primary THA cases (27 patients) of one surgeon (January 2021-April 2021) using the ABMS approach was conducted. These 30 THAs were compared to 30 primary THA cases (30 patients) done immediately prior to the transition by the same surgeon (September 2020-December 2020) using the posterior approach (PA). The Oxford Hip Score (OHS), Hip Disability and Osteoarthritis Outcome Score (HOOS Junior), and Forgotten Joint Score (FJS) obtained 6 weeks and 6 months after surgery were compared. In addition, three consecutive groups based on equal numbers of THAs were compared for the incidence of complications and surgery time. At 6 weeks after THA, the OHS was 6 points higher after the ABMS approach (p = 0.0408), and the OHS was comparable at 6 months. The HOOS Junior and FJS were similar at 6 weeks and 6 months after surgery.&#160;In the first 10 THAs using the ABMS approach, one patient had a greater trochanter fracture, and one patient had an intraoperative proximal femur fracture. No further immediate interoperative or postoperative complications occurred. Surgery time significantly reduced with the number of THAs performed. Transitioning from the PA to the ABMS approach is associated with a learning curve, which is limited to the first 20 cases. The effect of improved clinical outcomes is apparent within the early postoperative period. After 6 months, THA patients do well regardless of the approach.

The anterior-based muscle-sparing approach for total hip arthroplasty (THA) is associated with a learning curve. However, the improved clinical outcome in the early post-operative phase makes the consideration to transition worthwhile.

Surgeons considering transitioning to an anterior-based approach for THA are concerned about the learning curve and the reported marginal clinical ...

Three-Dimensional Preoperative Virtual Planning in Derotational Proximal Femoral Osteotomy

Anterior knee pain (AKP) is a common pathology among adolescents and adults. Increased femoral anteversion (FAV) has many clinical manifestations, including AKP. There is growing evidence that increased FAV plays a major role in the genesis of AKP. Furthermore, this same evidence suggests that derotational femoral osteotomy is beneficial for these patients, as good clinical results have been reported. However, this type of surgery is not widely used among orthopedic surgeons.
The first step in attracting orthopedic surgeons to the field of rotational osteotomy is to give them a methodology that simplifies preoperative surgical planning and allows for the previsualization of the results of surgical interventions on computers. To that end, our working group uses 3D technology. The imaging dataset used for surgical planning is based on a CT scan of the patient. This 3D method is open access (OA), meaning it is accessible to any orthopedic surgeon at no economic cost. Furthermore, it not only allows for the quantification of femoral torsion but also for carrying out virtual surgical planning. Interestingly, this 3D technology shows that the magnitude of the intertrochanteric rotational femoral osteotomy does not present a 1:1 relationship with the correction of the deformity. Additionally, this technology allows for the adjustment of the osteotomy so that the relationship between the magnitude of the osteotomy and the correction of the deformity is 1:1. This paper outlines this 3D protocol.

This work presents a detailed surgical planning protocol using 3D technology with free open-source software. This protocol can be used to correctly quantify femoral anteversion and simulate derotational proximal femoral osteotomy for the treatment of anterior knee pain.

Anterior knee pain (AKP) is a common pathology among adolescents and adults. Increased femoral anteversion (FAV) has many clinical manifestations, ...

Pedicle Screw Placement Using an Augmented Reality Head-Mounted Display in a Porcine Model

This protocol helps assess the accuracy and workflow of an augmented reality (AR) hybrid navigation system using the Magic Leap head-mounted display (HMD) for minimally invasive pedicle screw placement. The cadaveric porcine specimens were placed on a surgical table and draped with sterile covers. The levels of interest were identified using fluoroscopy, and a dynamic reference frame was attached to the spinous process of a vertebra in the region of interest. Cone beam computerized tomography (CBCT) was performed, and a 3D rendering was automatically generated, which was used for the subsequent planning of the pedicle screw placements. Each surgeon was fitted with an HMD that was individually eye-calibrated and connected to the spinal navigation system.
Navigated instruments, tracked by the navigation system and displayed in 2D and 3D in the HMD, were used for 33 pedicle cannulations, each with a diameter of 4.5 mm. Postprocedural CBCT scans were assessed by an independent reviewer to measure the technical (deviation from the planned path) and clinical (Gertzbein grade) accuracy of each cannulation. The navigation time for each cannulation was measured. The technical accuracy was 1.0 mm &#177; 0.5 mm at the entry point and 0.8 mm &#177; 0.1 mm at the target. The angular deviation was 1.5&#176; &#177; 0.6&#176;, and the mean insertion time per cannulation was 141 s &#177; 71 s. The clinical accuracy was 100% according to the Gertzbein grading scale (32 grade 0; 1 grade 1). When used for minimally invasive pedicle cannulations in a porcine model, submillimeter technical accuracy and 100% clinical accuracy could be achieved with this protocol.

The augmented reality head-mounted display, Magic Leap, was used in combination with a conventional navigation system to place pedicle screws in a porcine model by adhering to a novel workflow. With a median insertion time of &lt;2.5 min, submillimeter technical accuracy and 100% clinical accuracy were achieved according to Gertzbein.

This protocol helps assess the accuracy and workflow of an augmented reality (AR) hybrid navigation system using the Magic Leap head-mounted display (HMD) ...

Clinical Application of Artificial Intelligence Preoperative Planning System Combined with Expert Database Retrieval in Complex Revision Hip Surgery

Accurate preoperative planning in revision hip arthroplasty is crucial for achieving successful outcomes. To enhance the intuitive evaluation of acetabular bone defect severity and leverage previous successful experience in revision hip arthroplasty, this study proposes a novel approach based on expert surgical case database retrieval and is initially implemented in clinical application.&#160;In this study, five patients who required revision hip arthroplasty were preoperatively planned to employ the expert case database surgical planning system.The patient&#39;s imaging data was entered into the system and matched with cases in the expert case database. Based on the expert&#39;s surgical experience, a revision surgery plan was recommended. If no suitable case was found, the model and position of the prosthesis were planned based on patient-specific reconstruction results. A total of five patients were enrolled in this study, four males and one female, with a mean age of 50.6 years. The diagnosis was aseptic prosthesis loosening after hip arthroplasty. The mean operative time was 123.2 min, and the mean intraoperative hemorrhage was 672 mL. No intraoperative complications, such as vascular or nerve injury, were observed. In Case 2, for instance, the application of this innovative planning scheme enabled the surgeon to delineate the revision surgery plan for this patient in the preoperative period, thereby reducing the operative time and intraoperative hemorrhage. Furthermore, patients could be apprised of the outcomes of analogous cases in advance. Leveraging a big data analysis approach through our comprehensive case database enables automated identification of matching expert treatment plans throughout the entire process. This particularly benefits inexperienced orthopedic surgeons by providing accurate guidance on surgical strategies to assist them in selecting appropriate prosthetic sizes and mounting positions. Additionally, the matching results can offer patients visualizations depicting predicted postoperative outcomes.

This study proposes a novel artificial intelligence preoperative planning approach based on expert surgical case database retrieval in revision hip arthroplasty. Additionally, the technique was initially employed in five patients, exhibiting a reduction in operative time and intraoperative hemorrhage.

Accurate preoperative planning in revision hip arthroplasty is crucial for achieving successful outcomes. To enhance the intuitive evaluation of ...

Mixed Reality Technology and Three-Dimensional Printing in Teaching: Heart Anatomy as an Example

Mixed reality technology and three-dimensional (3D) printing are becoming more and morecommon in the field of medicine. During the COVID-19 pandemic and immediately after the restrictions had beeneased, many innovations were implemented in the teaching of future doctors. There was also interest in immersive techniques and 3D printing technology in anatomy teaching. However, these are not common implementations. In 2023, 3D prints and holograms in mixed reality technology were prepared for classes focused on the structure of the heart. They were used to teach students, who, with the support of engineers, could learn about the detailed structure of the heart and familiarize themselves with the new technologies that support the traditional model of learning on human cadavers. Students findthis possibility to be highly valuable. The article presents the process of preparing materials for classes and further implementation possibilities. The authors see an opportunity for the development of the presented technologies in students'teaching at various levels of education and the justification for increasingly widespread implementation.

Here, we describe a protocol for constructing a heart model from scratch based on computed tomography and present it to medical students using three-dimensional (3D) printing and mixed reality technology to learn anatomy.

Mixed reality technology and three-dimensional (3D) printing are becoming more and morecommon in the field of medicine. During the COVID-19 pandemic and ...