Guideline for Posterior Atlantoaxial Internal Fixation Assisted by Orthopaedic Surgical Robot

Basic Information

• Full English Title: Guideline for Posterior Atlantoaxial Internal Fixation Assisted by Orthopaedic Surgical Robot
• Issuing Authority: Chinese Society of Biomedical Engineering
• Publication Date: April 22, 2019
• Target Audience: Spine surgeons, operating room nurses, surgical robot engineers and other personnel involved in robot‑assisted orthopaedic spine surgery

Core Overview

1. Indications

• Atlantoaxial joint instability of various etiologies, with or without bulbomedullary compression.
• Congenital spinal anomalies: atlas dysplasia (e.g., occipitalization of the atlas), axis dysplasia (e.g., os odontoideum), basilar invagination, Klippel‑Feil syndrome.
• Spinal trauma: odontoid fractures, transverse ligament injuries.
• Autoimmune diseases and tumors: rheumatoid arthritis, tumors that compromise atlantoaxial joint stability.

2. Contraindications

• Severe systemic diseases contraindicating general anesthesia or major surgery, such as severe hemorrhagic disorders and respiratory failure.
• Inability to achieve the required surgical patient positioning.
• Patient intolerance to intraoperative radiation exposure.
• Inability to place trackers in positions that ensure accurate navigation.
• Failure to obtain qualified intraoperative navigation imaging data.

3. Standardized Surgical Workflow

3.1 Preoperative Preparation

• Complete imaging evaluations: cervical spine X‑ray, CT, MRI to clarify anatomy, fracture patterns, and spinal cord status.
• Perform routine preoperative assessments: coagulation function, cardiopulmonary function, thromboembolism risk, and anesthesia risk evaluation.
• Plan screw trajectories, diameters, and lengths collaboratively by the surgeon and robot technician based on imaging data.

3.2 Intraoperative Procedures

1. Anesthesia and Positioning: Administer general anesthesia; place the patient in the prone position, fix the head with a Mayfield clamp in a neutral or slightly flexed posture, and maintain rigid head‑neck stabilization.
2. Surgical Exposure: Make a midline posterior cervical incision, dissect layer by layer to expose the C1 and C2 screw entry points, and minimize soft tissue stripping.
3. Tracker Installation and Imaging: Attach reference trackers firmly (e.g., to the Mayfield head frame or adjacent spinous processes), perform intraoperative CT scanning (e.g., O‑arm), and transmit image data to the robotic system for registration.
4. Registration Verification: Validate registration accuracy using anatomical landmarks with a navigation wand to eliminate registration errors.
5. Robotic Guidance and Screw Implantation: Position the robotic arm, automatically align with the planned trajectory, drill the pilot hole, cannulate the tract, confirm no cortical breach with a probe, and insert the screw of appropriate size.
6. Reduction and Fixation: Install connecting rods, perform reduction maneuvers as needed, lock screws, and verify reduction and screw positioning via fluoroscopy.
7. Wound Closure: Perform bone grafting, place drainage, irrigate the wound, achieve hemostasis, and close the incision in layers.

3.3 Postoperative Management

• Conduct routine postoperative imaging (X‑ray/CT) to confirm screw position and fusion segment alignment.
• Monitor neurological function, vital signs, and wound drainage; manage pain and prevent thromboembolism.
• Guide postoperative immobilization and rehabilitation based on fixation stability and bone graft healing progress.

4. Key Precautions

• Strictly verify robotic system registration before screw implantation; repeat registration if accuracy is compromised.
• Account for factors affecting navigation accuracy: soft tissue tension, bony surface irregularities, and instrument deflection, with real‑time system alerts.
• The robotic arm maintains a consistent trajectory across drilling, cannulation, and screw insertion, reducing wobble and enhancing screw purchase strength.
• Surgeons must complete standardized robotic surgery training before performing independent procedures.