What is the role of virtual surgical planning in zygomatico maxillary complex (ZMC) fractures?

Virtual Surgical Planning in Zygomaticomaxillary Complex Fractures

Virtual surgical planning significantly improves accuracy, reduces surgical time, and decreases postoperative complications in the management of zygomaticomaxillary complex (ZMC) fractures compared to traditional approaches. 1

Diagnostic Imaging for ZMC Fractures

• Multidetector CT (MDCT) is the gold standard for diagnosing ZMC fractures 2

  • Provides superior delineation of osseous and soft-tissue structures
  • Allows detection of subtle nondisplaced fractures
  • Essential for determining zygomaticosphenoid suture status, an indicator of asymmetry and orbital volume changes

• 3D reconstructions from CT data are critical for preoperative planning 2

  • Many surgeons find 3D reformations essential for complex fracture characterization
  • Allows for better visualization of fracture patterns and displacement

Virtual Surgical Planning Methods

Two main approaches to virtual surgical planning for ZMC fractures:

1. Virtual Reduction Method 1

   • Most accurate approach (mean discrepancy of 0.175 mm between pre- and post-operative CT)
   • Shortest average surgical time (89.5 minutes)
   • Involves digital manipulation of fracture fragments to achieve optimal reduction

2. Mirroring Method 1, 3

   • Uses uninjured side as template for reconstruction
   • Less accurate than virtual reduction (mean discrepancy of 0.403 mm)
   • Slightly longer surgical time (94.25 minutes)
   • Particularly useful for restoring orbital volume in high-energy ZMC injuries

Both methods significantly outperform traditional approaches (mean discrepancy of 0.875 mm, average surgical time of 96.75 minutes) 1.

Clinical Implementation Process

1. Obtain high-quality CT maxillofacial scan 2, 4

   • Essential first-line diagnostic modality
   • Consider concurrent CT head as 68% of facial fracture patients have associated head injuries

2. Create 3D virtual models 3

   • Convert CT data into 3D models using specialized software (e.g., Mimics)
   • Perform virtual surgical planning and design of reduction strategy

3. Design and fabricate surgical guides 3

   • Create stereolithographic models for preplating
   • Develop patient-specific templates to guide reduction

4. Surgical execution with digital guidance 1, 3

   • Use prefabricated templates during surgery
   • Follow virtual plan for fracture reduction and fixation

Benefits of Virtual Surgical Planning

1. Improved Accuracy 1, 3, 5

   • More precise fracture reduction
   • Better restoration of facial symmetry
   • Improved concordance of bilateral orbital volumes

2. Reduced Surgical Time 1

   • Virtual reduction: 89.5 minutes
   • Mirroring: 94.25 minutes
   • Traditional approach: 96.75 minutes

3. Decreased Complications 1

   • Lower rates of postoperative issues
   • Better functional and aesthetic outcomes

Limitations and Considerations

• Computer-assisted navigation systems (CANS) show no significant improvement in reduction accuracy for type B ZMC fractures compared to conventional surgery 6

  • Median translational and rotational reduction errors were similar between navigation-aided and conventional surgery

• Technical expertise required for implementation of virtual planning workflows 5

• Cost and resource implications may limit widespread adoption

Outcome Assessment

• Postoperative CT scans should be obtained within 2 weeks after surgery 3
• Quantitative measurements to assess surgical outcomes:
  • Comparison of bilateral orbital volumes
  • Measurement of distances from marker points to reference planes
  • Assessment of facial symmetry using cephalometric landmarks 5

Virtual surgical planning represents a significant advancement in the management of ZMC fractures, offering superior precision and outcomes compared to traditional approaches. The virtual reduction method appears to be the most effective strategy, though both virtual planning methods demonstrate clear advantages over conventional techniques.