The Journal of Pain Summary

Highlight from The Journal of Pain (Volume 20, No. 3, March 2019)

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Deep Tissue Incision Enhances Spinal Dorsal Horn Neuron Activity During Static Isometric Muscle Contraction in Rats

He Gu, Daisuke Sugiyama, Sinyoung Kang, Timothy J. Brennan Department of Anesthesia, Department of Pharmacology, Roy J. and Lucille A. Carver

Completion of various activities is an important milestone for recovery and hospital discharge after surgery. Severe acute postoperative pain often complicates the recovery process after surgery and can lead to prolonged hospitalization associated with respiratory and cardiovascular complications.

Cutaneous responses are most often studied, but the need to study deep tissue injury is gaining importance. In this animal model, the authors hypothesized that deep tissue incision causes greater activation of nociception-transmitting neurons evoked by muscle contraction. Neuronal activity was recorded in 203 dorsal horn neurons from 97 rats.

The authors concluded that incision in skin plus deep muscle caused more activity, suggesting that deep tissue injury is a generator of ongoing nociception and that deep muscle injury contributes to activity-evoked hyperalgesia after surgery. The response of spinal dorsal horn neurons to static muscle contraction may model and inform mechanisms of dynamic pain after surgery.