Response to Treatment for Pectoralis Minor Myofascial Pain Syndrome After Whiplash

Abstract

Objective: This case study was conducted to investigate the role of myofascial trigger points of the pectoralis minor muscle in producing symptoms following whiplash injury. Methods: To be included in this retrospective study, patents were required to exhibit an active myofascial trigger point in at least one pectoralis minor muscle and should not have received therapy directed at myofascial pain syndrome prior to evaluation by the authors. other exclusions included bone fracture, cervical radiculopathy/myelopathy, and brain injury. Treatment without controls of the 37 patients included physical therapy measures selected to relieve the myofascial pain syndrome. Patients whose symptoms proved resistant to physical therapy received two or more courses of therapy and injection of their trigger points. By assessment that was not blinded as to intervention, a successful outcome lasting at least 6 months depended upon the subject being pain free or sufficiently improved with a continuing home self-stretch program that normal activities could be resumed. Results: A complex of clinical characteristics common to all patients included pain at the neck radiating to the upper limb, and a positive hyperabduction maneuver. Together, these findings fit the diagnosis of a pectoralis minor myofascial pain syndrome. The patients divided conveniently into three groups based on the time required to reach symptomatic relief [<6 months, N = 12; 6-18 months, N = 13; and >18 months, N = 5]. The rate of progress was not related to age, sex, direction of impact, delayed onset of symptoms, or the location of symptoms. Variables which correlated with delayed recovery included a long delay before initiating therapy, a large number of trigger points, a bulging cervical disc by MRI, nerve conduction velocity evidence for compression neuropathy of the ulnar component of the brachial plexus where it lies deep to the pectoralis minor tendon, and reinjury. Conclusion: Prompt recognition and treatment of a pectoralis minor myofascial syndrome caused by whiplash injury should reduce suffering, lower medical costs, and reduce loss of productivity.

KEYWORDS:

• Myofascial pain syndrome
• pectoralis minor muscle
• thoracic outlet syndrome
• whiplash injury