Clinical Scorecard: Effects of Lateral Orbital Rim Resection on Intraorbital Pressure in Endoscopic Trans-Orbital Approaches: A Cadaver Study

At a Glance

Key Highlights

• Orbital retraction beyond 1.5 cm depth from lateral orbital rim significantly increases intraocular pressure to dangerous levels.
• Removal of the lateral orbital rim (LOR) expands surgical corridor and may influence intraorbital pressure during surgery.
• Intraorbital pressure monitoring using a solid-state strain-gauge microtransducer provides real-time, direct pressure measurements within the orbit.

Guideline-Based Recommendations

Diagnosis

• Monitor intraorbital pressure as a surrogate for intraocular pressure during endoscopic transorbital approaches to prevent optic nerve damage.

Management

• Consider removal of the lateral orbital rim at the start of the procedure to increase working space and potentially reduce orbital content compression.
• Maintain retraction depth less than 1.5 cm from the lateral orbital rim to avoid excessive intraorbital pressure.

Monitoring & Follow-up

• Use direct intraorbital pressure monitoring with microtransducer probes placed in extraconal fat for continuous real-time pressure assessment.
• Zero pressure monitoring devices to atmospheric pressure before each procedure to ensure accuracy.

Risks

• Excessive orbital retraction can cause diplopia, ptosis, proptosis, enophthalmos, redness, swelling, and visual disturbances.
• Increased intraocular pressure from retraction may lead to irreversible optic nerve hypoperfusion and retinal detachment.

Patient & Prescribing Data

Patients undergoing endoscopic transorbital approaches for ventral skull base access

Lateral orbital rim removal may improve surgical access and reduce intraorbital pressure increases associated with orbital retraction, potentially minimizing complications.

Clinical Best Practices

• Perform superior eyelid crease incision approximately 6–10 mm above the palpebral fissure to access lateral orbital rim.
• Dissect orbicularis oculi muscle fibers along their direction to preserve anatomy and avoid injury.
• Initiate periorbita detachment at Whitnall’s Tubercle to reduce risk of periorbital injury.
• Use subperiosteal dissection to expose lateral orbital rim and create working space while protecting periorbita.
• Maintain cadaveric or patient head in neutral horizontal position during pressure monitoring to standardize hydrostatic reference.

References

• Kim et al. on intraorbital pressure and retraction depth
• Codman Microsensor® ICP Transducer technical details
• Endoscopic transorbital approach techniques and complications