Effect of Palpatory Neuromodulation of the Trigeminal Nerve for Tenderness in the Posterior Neck Musculature

Purpose: The trigeminal nerve coordinates several reflexes in the head, including a head-retraction reflex (HRR) when a stimulus comes close to the face. HRR utilizes the posterior neck musculature (PNM) to remove the face from potential danger. PNM has been identified as a possible source of discomfort in headaches, muscular tightness, and chronic neck pain. Neuromodulation is the mechanical, electrical or magnetic stimulation used to affect a change in the signaling circuitry of a nerve to affect how sensory inputs are processed via neurotransmitters. Our goal in using neuromodulation on the trigeminal nerve where it exits the face is to influence the circuitry of this reflex to decrease the tension and pain of the posterior neck musculature. Osteopathic manipulative treatment (OMT) has many modalities, one of which is using constant palpatory pressure, or inhibition, for relief of discomfort. Typically, inhibition has been used with muscular tender points and other somatic issues. We are using the OMT palpatory pressure on specific points of the face where the branches of the trigeminal nerve are known to reside. This study investigated change in tenderness of the PMN before and after using an OMT-based neuromodulation intervention as constant pressure on facial trigeminal points. We hypothesized a decrease in tenderness of the PNM after the intervention. Methods: Fifty-two out of 100 subjects have been recruited thus far, 9 of which were excluded for no discomfort on initial assessment. The PNM was assessed for tenderness bilaterally using a 0-10 pain scale. If tenderness was present, the V1 and V2 branches of the trigeminal nerve endings on the face were assessed with an average pressure of 1.5±.21 lbs (left hand) and 1.6±.25 lbs (right hand), then given the 30-second neuromodulation OMT intervention. Using the IsoTouch system, average pressure used for intervention was 1.92 ±.16 lbs (left) and 1.92 ±.34 lbs (right). Results: The average change in pain pre to post PNM right versus left side is R 1.50±1.54 and L 1.48±1.44. Conclusions: The variability seen in the 52 subjects in our pre to post-intervention suggests neck pain is a multifaceted issue. The range of how the tenderness changed could indicate a role for the HRR circuitry as a target for neuromodulation. Length of neuromodulation, the amount of pressure used, and indication for intervention are all possibilities for future research. Study funded by American Osteopathic Association #291PIT1811606