Sensory Action Potentials of the Maxillary Nerve: A Methodologic Study With Clinical Implications

Purpose: Recently, recording of sensory nerve action potentials (SNAPS) of the inferior alveolar nerve (IAN) was described and is used as a diagnostic test of traumatic neuropathic trigeminal disorders. The technique is limited to IAN damage; therefore, we adapted the technique to the maxillary nerve, which is also frequently injured by either trauma or orthognathic surgery. Patients and Methods: Fourteen healthy volunteers participated in this methodologic study in which the infraorbital nerve (ION) was stimulated with 2 needle electrodes. The SNAPS were recorded from the maxillary nerve with a unipolar needle electrode close to the foramen rotundum. Results: The mean latency of the SNAPS was 0.73 ms (95% CI, 0.55 to 0.85 ms) with a 0.08 +/- 0.09 ms interside difference. The mean baseline to peak amplitude was 31.3 +/- 7.0 mu V (95% CI, 24.2 to 38.3 mu V) with a 6.5 +/- 32.4 mu V interside difference. Repeated tests within a session test demonstrated no significant differences in the latency data (ANOVA: P = .225) or amplitude data (ANOVA: P = .44). Stimulus-response curves indicated that the SNAPS saturated at 5.1 +/- 4.4 mA stimulus intensity. In 1 subject, stimulation of the mental nerve elicited SNAPs (latency: 1.6 ms; amplitude 38 mu V) in accordance with published values. A local anesthetic block of the TON was associated with a distinct decay of the SNAP in 1 Subject. Conclusion: We suggest that SNAPS of the maxillary nerve can be a valuable technique for a comprehensive examination of the trigeminal system. (C) 2009 American Association of Oral and Maxillofacial Surgeons