iASSIST® Knee 2-Pod Version Surgical Technique
Table of Contents Overview............................................................................................................................................... 2 Indication for Use...................................................................................................................... 2 Training.......................................................................................................................................... 2 Implant Indications................................
2 | iASSIST 2-Pod Version Surgical Technique 1.Overview 1.1 Indication for Use The iASSIST™ Knee System is a computer assisted stereotaxic surgical instrument system to assist the surgeon in preparing the bone surfaces for positioning orthopedic implant system components intra-operatively. It involves surgical instruments and inertial sensors to determine alignment axes in relation to anatomical landmarks and to precisely position alignment instruments and cut guides relative to these axes.
3 | iASSIST 2-Pod Version Surgical Technique 2.Preoperative Guide Figure 2.0 Operationg Room Setup Warning: The surgical procedure must take place in an operating room theater with temperatures ranging from 15°C to 30°C (59°F to 86°F). Ensure that the Pods are maintained in this temperature range before being use in a surgical procedure. Otherwise, the system will indicate that the Pods are outside their operational temperature range and the Pods cannot be used until they reach an adequate temperature.
4 | iASSIST 2-Pod Version Surgical Technique Figure 2.1 iASSIST V2 Tablet Setup 3. Lift the white silicon lid located on the bottom right side of the tablet and connect the power supply to the Tablet port. Then connect the power cord to the power supply and plug it into an AC outlet. Warning: The iASSIST V2 Tablet is: a. not intended to be used in the sterile zone; and b. to be connected to an AC outlet during the entire procedure. The Tablet must not be placed in a sterile bag as it might overheat. 4.
5 | iASSIST 2-Pod Version Surgical Technique Figure 2.2 Application Launch 2.2 Application Launch and Patient Side Selection 1. Press the green iASSIST icon displayed on the iASSIST V2 Tablet home screen. The barcode scanner window will open and the barcode scanner will start automatically and stay active for 30 seconds. 2. Place the barcode in the barcode scanner field of view. Press on the “Scan” button to restart the scanner if needed.
6 | iASSIST 2-Pod Version Surgical Technique Figure 2.3.1 Settings and Screenshot buttons Figure 2.3.3 Audio and Barcode buttons 2.3 Buttons, Icon and Pod Status Bar 2.3.1 Settings Button 2.3.3 Audio Button Click the “Settings” button located at the bottom of the iASSIST V2 Tablet screen to modify the operative side or enter the desired cut targets for “Tibia Slope Target” and “Femur Flexion Target”. These settings can be modified either before or during a surgical procedure.
7 | iASSIST 2-Pod Version Surgical Technique Figure 2.3.5 Patient Side Icon: Right, Left, Undetermined Figure 2.3.6 Pod Status Bar Buttons, Icon and Pod Status Bar (cont.) 2.3.5 Patient Side Icon The patient side is indicated at the top of the iASSIST V2 Tablet screen. When the patient side is set, the icon and letter are white on the selected side. If the patient side is not determined the icon is entirely white with a “?” sign.
8 | iASSIST 2-Pod Version Surgical Technique 3. Intraoperative Guide Note: Through this surgical technique, images from a left knee procedure are shown. Figure 3.1.1 Femur Instrument Assembly 3.1 Instrument Assembly 3.1.1 Femur Instrument Assembly 1. Insert the Femoral Saw Slot into the Femoral Distal Cut Guide and tighten it at the “0” position with a 3.5 mm hex head screwdriver.
9 | iASSIST 2-Pod Version Surgical Technique Figure 3.1.2 Tibia Instrument Assembly 3.1 Instrument Assembly (cont) 3.1.2 Tibia Instrument Assembly Note:There are three different techniques for tibia resection.The first one is the Freehand Positioning of the Tibial Adjustment Mechanism and will be described here. Two more techniques will be described in section “Alternative Techniques to Prepare For Tibia Cut”.
10 | iASSIST 2-Pod Version Surgical Technique Figure 3.2 Powering-On Pods and intraoperative Calibration 3.2 Powering On the Pods and Intraoperative Calibration Warning: Verify that the packaging is not damaged. A damaged package may affect the sterility of the Pods. If damage to the sterile packaging is observed, discard the damaged Pod kit and open another iASSIST Knee Pod Kit. 1. Open an iASSIST Knee Pod Kit and remove the Pods from the Pod Tray. Place them on the sterile instrument table. 2.
11 | iASSIST 2-Pod Version Surgical Technique Figure 3.2 Powering-On Pods and intraoperative Calibration (cont) 3.2 Powering-On Pods and Intraoperative Calibration (cont) Warning: The calibration process including the Pod Calibration Jig handling must be performed wearing sterile attire. The Pods need to be calibrated on a flat, approximately horizontal surface to ensure optimal performance. This surface must be sterile and free of any movement or vibrations. 4.
12 | iASSIST 2-Pod Version Surgical Technique Figure 3.3 Assembling a Pod to an Instrument 3.3 Pod Assembly To clip and unclip a Pod on any of the iASSIST Knee instruments (except the calibration jig) with the user interface of the Pod facing upwards; 1. Identify the nose on the narrow side of the Pod and insert it in the corresponding recess. 2. Clip the other side of the Pod on the instrument until the spring holder engages.
13 | iASSIST 2-Pod Version Surgical Technique Figure 3.4.1 Workflow Selection 3.4 Femur Procedure The iASSIST Knee system is compatible with Femur first and Tibia first procedure. See the “Tibia Procedure” section to start with the tibia. 3.4.1 Workflow Selection for Femur To Start a femur first procedure: 1. Clip the“Reference”Pod to the Femoral Reference. 2. Identify the femur mechanical axis entry point. 3.
14 | iASSIST 2-Pod Version Surgical Technique Figure 3.4.1 Workflow Selection (cont) 3.4 Femur Procedure (cont) 4. Slide the Femoral Reference onto the spike. 5. Align the Femoral Reference in a neutral rotation position. Note: The femoral rotation may be set by: a. Aligning the indicator arrow at the end of the Femoral Reference to Whiteside’s line; b. Aligning a pin inserted in the dedicated medial-lateral hole on the body of the Femoral Reference to the epicondyles. 6.
15 | iASSIST 2-Pod Version Surgical Technique Figure 3.4.2 Femoral Registration 3.4.2 Femoral Registration Warning: From registration to validation, the instruments must remain stable and properly fixated to the bone to ensure accuracy of the system. 1. Press the “Z” button on the Pod attached to the Femoral Reference to initiate the registration procedure. 2. Acquire 13 stable positions by accelerating and stopping the leg to create a star-shaped pattern.
16 | iASSIST 2-Pod Version Surgical Technique Figure 3.4.3 Distal Femur Cut 3.4.3 Distal Femoral Cut Guidance 1. Install the Femoral Adjustment Mechanism on the anterior side of the Femoral Reference by aligning the arrows laser-marked on the instruments. 2. Clip the Cut Guide Pod on the Cut Guide and insert the two long pegs of the Femoral A/P Slider into the Femoral Adjustment Mechanism. 3. Slide the Femoral Adjustment Mechanism down towards the distal condyles to the half way mark. 4.
17 | iASSIST 2-Pod Version Surgical Technique Figure 3.4.3 Distal Femur Cut 3.4.3 Distal Femoral Cut Guidance (cont) 6. Insert three 3.2 mm Headless Trocar Drill Pins in the base of the Femoral Distal Cut Guide using both parallel holes and one diagonal hole in the body of the guide. 7. With the knee stable and flexed more than 45°, unlock the Femoral A/P Slider using the blue screw and remove it from the assembly. Hold the knee steady until the coordinate transfer confirmation sound is heard.
18 | iASSIST 2-Pod Version Surgical Technique Figure 3.4.3 Distal Femur Cut (cont) 3.4.3 Distal Femoral Cut Guidance (cont) 9. Remove the 3.5 x 38 mm Hex Head Screw and the Femoral Reference. 10. Remove the Femoral Spike using a slaphammer. Note: The Persona® Slaphammer and the The NexGen® Slaphammer Extractor can be used to remove the Femoral Spike. 11. Manually adjust the resection level if desired.
19 | iASSIST 2-Pod Version Surgical Technique Figure 3.4.3 Distal Femur Cut (cont) 3.4.3 Distal Femoral Cut Guidance (cont) 13.Optionally, a drop rod can be used to check the varus/valgus orientation of the cut before performing the resection. Insert the paddle section of the Alignment Arch into the Femoral Saw Slot. Make sure that the arm of the Alignment Arch is aligned with the A/P plane of the femur. Then, slide a drop rod in the body of the Alignment Arch.
20 | iASSIST 2-Pod Version Surgical Technique Abduction Adduction Neutral Figure 3.4.4 Distal Femur Cut – Validation 3.4.4 Distal Femoral Cut Validation 1. Remove the Pod attached to the Femoral Reference and clip it to the Validation Tool. 2. Position the flat surface of the Validation Tool onto the distal femoral cut. 3. Secure the Validation Tool on the distal femoral cut by gently impacting the captive spikes. Additionally two 3.5 x 38 mm Hex Head Screw can be used for more stability.
