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Comparison of the feasibility and safety of infrazygomatic and suprazygomatic approaches to pterygopalatine fossa using virtual reality
  1. Anže Jerman1,
  2. Nejc Umek1,
  3. Erika Cvetko1 and
  4. Žiga Snoj2,3
  1. 1 Institute of Anatomy, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
  2. 2 Institute of Radiology, University Medical Centre Ljubljana, Ljubljana, Slovenia
  3. 3 Department of Radiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
  1. Correspondence to Mr Anže Jerman, Institute of Anatomy, Faculty of Medicine, University of Ljubljana, Ljubljana, Ljubljana, Slovenia; anze.jerman{at}


Background Injections of local anesthetics into pterygopalatine fossa gained popularity for treating acute and chronic facial pain and headaches. Injury of maxillary artery during pterygopalatine fossa injection can result in pseudoaneurysm formation or acute bleeding. We aimed to identify the optimal approach into pterygopalatine fossa by comparing feasibility and safety of suprazygomatic and two infrazygomatic approaches.

Methods We analyzed 100 diagnostic CT angiographies of cerebral arteries using 3D virtual reality. Each approach was determined as a target point in pterygomaxillary fissure and an array of outermost edges trajectories leading to it. The primary outcomes were feasibility and safety for each approach. The secondary outcome was the determination of maxillary artery position for each approach to identify the safest needle entry point.

Results Suprazygomatic approach was feasible in 96.5% of cases, while both infrazygomatic approaches were feasible in all cases. Suprazygomatic approach proved safe in all cases, posterior infrazygomatic in 73.5%, and anterior infrazygomatic in 38%. The risk of maxillary artery puncture in anterior infrazygomatic approach was 14.7%±26.4% compared to 7.5%±17.2%. in posterior infrazygomatic with the safest needle entry point in the upper-lateral quadrant in both approaches.

Conclusion The suprazygomatic approach proved to be the safest, however not always feasible. The posterior infrazygomatic approach was always feasible and predominantly safe if the needle entry point was just anterior to the condylar process. The anterior infrazygomatic approach was always feasible, however least safe even with an optimal needle entry point just anterior to the coronoid process.

  • Autonomic Nerve Block
  • Nerve Block
  • Ultrasonography
  • Facial Pain

Data availability statement

Data are available on reasonable request.

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Data availability statement

Data are available on reasonable request.

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  • Contributors Conceptualization: AJ, EC, NU, and ŽS; methodology: AJ, EC, NU, and ŽS; formal analysis: AJ, NU, and ŽS; investigation: AJ, NU, and ŽS; resources: EC and ŽS; data curation: AJ, EC, NU, and ŽS; writing—original draft preparation: AJ and NU; writing—review and editing: AJ, EC, NU, and ŽS; supervision: EC and ŽS; author responsible for all content: AJ. All authors have read and agreed to the published version of the manuscript.

  • Funding This study was funded by Slovenian Research Agency (Grant No: P3-0043).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.