(736): Continuous regional anesthesia of maxillary nerve: Anatomical base of a new lateral approach to pterygopalatine fossa

Abstract

Craniofacial surgery pain treatment is one of the important and not yet resolved issues. Some studies demonstrated the interest of regional anaesthesia and analgesia. The aim of our study was to assess the feasibility of maxillary nerve block with the help of a catheter placed in the pterygopalatine fossa by a supra-zygomatic approach. Anthropomorphic measurements between foramen rotundum and selected bone landmarks (temporal margin of the zygomatic bone and infratemporal crest of the great wing of the sphenoid bone) were performed on 21 dry skulls (42 sides). The angle between distances from temporal margin of the zygomatic bone to the infratemporal crest and to the foramen rotundum was calculated for each side of dry skulls. Eight micro-anatomical dissections (four cephalic extremities) were performed with supra-zygomatic or trans-zygomatic approaches to the pterygopalatine fossa with the aim to explore anatomic relationship between maxillary nerve, sphenopalatine artery and venous plexus. In two specimens before dissection the insertion of the needle with a catheter to the pterygopalatin fossa by suprazygomatic approach with calculated angle of 7,6° ± 6,5 (mean± SD) in an inferior and posterior direction was performed with the progression up to 18,9 mm± 0,4 between the infratemporal crest and the final position of the needle. Five ml of the radio-opaque solution was injected via catheter and CT scan revealed solution in the pterygopalatine fossa, immersing maxillary nerve. In this described position the needle is far from the vascular structures and in a perpendicular direction with the inferior orbital fissure. Our technique of pterygopalatine fossa catheterize for maxillary nerve block is an easy and safe procedure. It seems that supra-zygomatic approach has no risk of complications such intra cranial penetration or orbital penetration. Randomised study should confirm the benefice of the supra-zygomatic approach in term of anaesthesia and analgesia.