Tactile Hypoesthesia Associated with Myofascial Trigger Points in Patients with Persistent Post-Mastectomy Pain: A Close Observation Study in A Case Series

Purpose: Numbness is frequently seen at or near the operated site in patients with persistent post-mastectomy pain (PPMP). Numbness including tactile hypoesthesia can be also seen in patients with myofascial pain. The purpose of this study was to observe relation between such tactile hypoesthesia and myofascial trigger points in patients with PPMP.
Methods: We studied five female patients from 43 to 74 years old who consulted at our pain clinic for treatment of PPMP. The areas of tactile hypoesthesia and anesthesia, myofascial trigger points, as well as diffuse tenderness, were marked on the skin surface with delineating such areas and putting X mark on the site of myofascial trigger points using aqueous markers and recorded in photographs at every visit.
Results: Tactile hypoesthesia and anesthesia were observed in five and four patients, respectively. Myofascial trigger points were identified in all the five patients and were located within, in the vicinity or near the same dermatomal levels of the hypoesthesia. A series of trigger point injections reduced NRS scores by more than 50% in all patients. The size of the area of tactile hypoesthesia was significantly reduced in association with the decrease of NRS scores in four patients.
Conclusions: Our findings indicate that tactile hypoesthesia is closely associated with myofascial pain, and myofascial pain is one potential pathophysiological cause of prolongation and exacerbation of PPMP. Our results also indicate that treating them with trigger point injections are useful for alleviating PPMP.