Guide to Scan and Plan Workflow

As robotic spine surgery continues to transform the field of spine surgery, understanding the scan and plan workflow is crucial for optimizing patient outcomes and enhancing surgical precision. This guide provides an in-depth look at the key steps in the robotic spine surgery process, empowering spine surgeons to leverage advanced technology effectively.

1. Intraoperative CT Scan Acquisition

The scan and plan workflow begins with acquiring intraoperative CT scans. These scans are essential for precise screw placement planning, allowing real-time navigation during the procedure.

Robot Registration: Step-by-Step

To ensure precise navigation and alignment with the patient’s anatomy, the robot must first be registered.

• 3Define Scan: Perform a 3Define scan to define the surgical work volume.

• Snapshot Tracker: Use the snapshot tracker to register the robot's navigation system with the patient’s anatomy.

• Mark Area of Interest: Mark the region of interest on the patient’s anatomy with a blunt passive planar probe.

• Position the Robot Arm: Center the “Star Marker” fiducial array on the target vertebra.

• Fine Adjustments: Make fine adjustments to bring the fiducial array close to the patient’s anatomy for accurate registration.

Maximizing Coverage for Optimal Precision

To ensure accurate robot navigation, the following steps should be followed:

• Star Marker Alignment: Position the "Star Marker" from the opposite side of the anatomy for full coverage.

• Table Adjustment: Raise the operating table to prevent any potential collisions between the robot and O-arm.

• Proximity to Anatomy: Lower the Star Marker as close to the anatomy as possible without direct contact.

2. Screw Planning: Precise Mapping for Accurate Placement

Once the CT scans are acquired and the images transferred to the robotic console, you can begin screw planning. This crucial step involves visualizing optimal screw trajectories and ensuring proper placement within the vertebrae.

Screw Planning Steps

1. Fiducial Marker Verification: Ensure that all four beads of the "Star Marker" are identified by the robot.

2. Draw the Region of Interest: Use the robot’s interface to define the region of interest (ROI) for screw planning.

3. Automatic Segmentation: Allow the robot to segment the vertebrae based on the CT data.

4. Label Segments: Label the vertebral segments (e.g., S1) for reference during screw planning.

5. Plan Screw Trajectories: Ensure screws are planned to be placed intra-pedicularly in all three axes (anteroposterior, lateral, and axial).

Tips for Thoracic Spine Cases

• Fluoroscopy Verification: Expose the spine first and use fluoroscopy to confirm the vertebral level before proceeding.

• Marking Pin: Place a marking pin on a known vertebra to aid segmentation during planning.

• Bony Destruction: In cases of bony destruction, fluoroscopy may be helpful for accurate level identification.

3. Advanced Planning Features Tips

The scan and plan workflow includes advanced features that significantly improve the accuracy and efficiency of screw placement and other spinal procedures.

Alignment of Tulips

• Visualize Rod Contour: Check the lateral view for rod contour and ensure the tulips are aligned in the AP view (crucial for minimally invasive surgeries).

Skin Level Planning

• Single Incision Planning: Use the skin level tool to determine which screws can be placed through a single incision.

• Optimal Screw Sequence: Plan the screw insertion sequence, starting with the middle screw in clustered placements for optimal access.

4. Screw Placement Techniques: Efficient Insertion for Lumbar and Thoracic Regions

With robotic assistance, screw placement in both the lumbar and thoracic spine can be done with greater precision.

Lumbar Spine Screw Placement

1. Percutaneous Incisions: Make percutaneous lateral incisions for minimally invasive access.

2. Customized Knife: Use the robotic arm to insert a customized knife for skin and fascia incision.

3. Dilator and Sleeve: Insert the sleeve with a dilator through the robotic arm, then remove the dilator.

4. Pilot Hole Creation: Use a high-speed drill to create the pilot hole for screw insertion.

5. Screw Insertion: Tap the track and insert the screw to the correct depth.

6. Navigation Assistance: Utilize navigation to visualize and guide drilling, tapping, and screw insertion depth.

Thoracic Spine Screw Placement

1. Exposing the Thoracic Spine: Expose the thoracic spine prior to screw insertion for better visualization.

   

2. Flatten Transverse Processes: Flatten the transverse processes to avoid skiving during screw placement.

   
   
   
   

3. Bone Wax: Plug raw bone areas with wax to reduce blood loss during the procedure.

4. Central Screw Placement First: Place central screws first to reduce soft tissue pressure on the robot arm.

   
   
   
   

5. Peripheral Screw Considerations: For peripheral screws, consider a transmuscular or transfascial approach to minimize risks of medial displacement.

   
   
   
   
   
   
   
   

5. Special Considerations for Unique Patient Demographics

In specific patient cases, adjustments to the robotic workflow may be required to ensure optimal outcomes.

Obese Patients

• Long Schanz Pin: Use a long Schanz pin for semirigid mounting of the robot in obese patients.

• Star Marker Position: Position the Star Marker close to the patient’s anatomy without direct contact.

  

• Long Tools and Sleeves: Use extended tools and sleeves for trajectory preparation in patients with high BMI.

• Adjust O-arm Settings: Modify O-arm settings to account for increased patient thickness.

6. Additional Capabilities: Beyond Screw Placement

The scan and plan workflow in robotic spine surgery goes beyond screw placement and can be used for more advanced procedures.

• Navigable Cages: The workflow supports the placement of navigable cages for spinal fusion surgeries.

  

• Navigable Burr: The robotic system can assist with procedures like Posterior Vertebral Column Resection (PVCR) using a navigable burr for precise bone resection.

  
  

  

  
  
  
  
  
  

Conclusion

By understanding the intricacies of this process and utilizing advanced features of the robotic system, spine surgeons can enhance precision, reduce complications, and improve overall patient care.

Practice and experience are key to becoming proficient in robotic spine surgery. As you incorporate these workflows into your practice, you’ll continually discover ways to optimize your approach and deliver better results for your patients.