The accuracy of distal posterior interosseous and anterior interosseous nerve injection

Purpose: To standardize a technique of delivering a local anesthetic to the posterior interosseous nerve (PIN) and anterior interosseous nerve (AIN) by using the anatomic landmarks of the wrist and to evaluate the accuracy of the technique in a cadaver model. Methods: Techniques for PIN and AIN injection and for PIN injection alone are described. Techniques were tested in a fresh frozen cadaver model by using methylene blue injections. Stained nerves were dissected under loupe magnification. Digital photographic images were taken of each nerve. Staining was quantified by calculating the mean density and area stained. Results: For both techniques methylene blue was delivered accurately to the PIN in 100% of the samples. Methylene blue was delivered accurately to the AIN in 100% of samples in which it was injected. Conclusions: These techniques saturated successfully the PIN and AIN and may be useful as diagnostic and therapeutic tools for chronic wrist pain and in evaluating presurgically the effectiveness of partial wrist denervation.