Simulation of suprazygomatic and infrazygomatic approaches for maxillary nerve block in children

To compare the feasibility and risk of arterial injury associated with suprazygomatic and infrazygomatic maxillary nerve block approaches in children using 3D virtual reality.

Suprazygomatic, anterior and posterior infrazygomatic approaches were simulated bilaterally using computed-tomography angiography datasets of 89 children (0-18 years). Feasibility and vascular safety were assessed by positioning trajectories from the simulated needle end-point to the skin in respect to bones and maxillary artery, respectively. Solid angles and skin entry areas were quantified, correlated with age, and complemented by quadrant analysis of maxillary artery.

The suprazygomatic approach was feasible in all 178 attempts and safe in 99.4%. It had the smallest skin entry area with a median of 1.48 [0.98-2.20] cm² and shortest skin-to-pterygomaxillary fissure distance of 45 [43-47] mm (both p < 0.0001). The anterior infrazygomatic approach was feasible in 98.9%, safe in only 42.6%; despite maximal solid angle reduction, 12/101 (11.9%) attempts remained unsafe. The posterior infrazygomatic approach was feasible in all 178 attempts and safe in 65.2%. In unsafe infrazygomatic approaches, the maxillary artery most commonly occupied inferior quadrants (56.4-98.4%). Age correlated with estimated skin area in all approaches (ρ = 0.18-0.29; p ≤ 0.016).

The suprazygomatic approach showed the most favorable feasibility and vascular safety profile, supporting its preferential use for maxillary nerve block in children. In infrazygomatic approaches, the maxillary artery frequently lay along potential needle trajectories and may represent a safety concern. For anterior infrazygomatic approach, the safest placement was just anterior to mandibular coronoid process, and for posterior just below zygomatic arch.