Identifying a Novel Critical Access Difficulty Factor in Percutaneous Radiofrequency Rhizotomy for Trigeminal...

Area of Science:

• Neurosurgery
• Anatomy
• Medical Imaging

Background:

• Percutaneous stereotactic radiofrequency rhizotomy (PSR) is an ablative treatment for trigeminal neuralgia (TN).
• Successful PSR relies on accurate navigation through the foramen ovale (FO).
• A previously undescribed anatomical variant, the pterygoid process ridge (PPR), can obstruct the FO, complicating PSR procedures.

Purpose of the Study:

• To identify and characterize variations of the pterygoid process ridge (PPR).
• To assess the impact of PPR variations on foramen ovale (FO) cannulation difficulty during PSR for trigeminal neuralgia (TN).

Main Methods:

• Analysis of 57 foramen ovale (FO) in trigeminal neuralgia (TN) patients and 438 FO in non-TN patients using 3D computed tomography (CT) reconstructions.
• Utilization of 3D printed models for TN patients with PPR-obscured FO.
• Morphometric measurements to evaluate the effect of PPR variations on cannulation.

Main Results:

• PPR-obscured FO was identified in 8.8% of TN patients and 7.3% of non-TN patients.
• Obstruction of FO transverse diameter by PPR ranged from 19.2% to 100% in affected TN patients.
• Approximately 25-33% of FO preset targets were impacted by the PPR.

Conclusions:

• PPR-obscured FO is a novel confounding factor in percutaneous stereotactic radiofrequency rhizotomy (PSR).
• Pre-procedural identification of PPR is crucial for accurate target presetting and improving cannulation success.
• Recognizing PPR variations enhances the effectiveness of PSR for trigeminal neuralgia (TN).