Anatomic study using three-dimensional computed tomographic scan measurement for truncal maxillary nerve blocks via the suprazygomatic route in infants.

A maxillary nerve block using external anatomic landmarks is a safe regional anesthesia for adults. However, the classic approach to the nerve may be difficult in infants. To use this block in infants, we describe the anatomical landmarks needed to reach the foramen rotundum area using the suprazygomatic route.Computed tomographic scans of 55 infants (mean age, 8.5 months; range, 1 week to 16 months) without any malformation were retrospectively evaluated using multimodal and multiplanar software. For each side, the distances and angles from the skin to the greater wing of the sphenoid and to the foramen rotundum area (representing the maxillary nerve) were measured in the axial and oblique planes.The distances from the skin at the frontozygomatic angle to the greater wing of the sphenoid in the axial plane and the foramen rotundum area in the oblique plane are 24.1 mm +/- 2.7 and 47.4 mm +/- 4.1, respectively. From the skin landmark, the direction of the trajectory was oriented 19.3 +/- 5.3 and 8.7 +/- 2.9 degrees forward. These distances and angles must be slightly adapted for infants younger than 6 months, although none of these parameters were correlated with age during the period studied.This anatomic study based on computed tomographic scan information may be useful for clinical application of the truncal maxillary nerve block in infants using the suprazygomatic route.