Investigation of the palatine approach as a novel technique to block the canine maxillary nerve: a comparative cadaveric study

Objectives

To develop a palatine approach to the canine maxillary nerve and compare its feasibility and the spread of dye and contrast medium with that of the infraorbital technique.

Materials and Methods

Ten canine cadaveric heads were used in this study. The maxillary nerve was approached bilaterally by inserting hypodermic needles into either the infraorbital or the palatine foramen on each side. Dye/contrast injections (1:1 solution) were followed by CT and anatomical dissections, performed to isolate the maxillary nerves and measure their stained portions. Procedural failure was defined as a nerve stain <6 mm in length. Descriptive statistics, analysis of proportions and comparison of either means or medians were used for data analysis.

Results

The stained portion of the maxillary nerve was shorter for the palatine technique (0 (0 to 10) mm) than the infraorbital technique (35 (17 to 52) mm) (P = .015). Procedural failure rate was higher for the palatine technique (80%) compared to the infraorbital technique (20%; P = .025). For both techniques, imaging showed contrast spread along the nerve pathway in 70% of injections. Contrast medium contamination of nasal turbinates and nasal passages did not differ between approaches and was observed in 50% of palatine and 30% of infraorbital injections (P = .057).

Clinical Significance

The novel palatine approach produced a higher procedural failure rate than the infraorbital technique and cannot be recommended as a suitable alternative to existing methods for canine maxillary nerve block.