Electromyographically Guided Trigger Point Injections in the Cervicothoracic Musculature of Obese Patients: A New and Unreported Technique

Abstract

Background: Myofascial pain is defined as pain that originates from myofascial trigger points in skeletal muscle. It is prevalent in regional musculoskeletal pain syndromes, either alone or in combination with other pain generators. The myofascial pain syndrome is one of the largest groups of under-diagnosed and under-treated medical problems encountered in clinical practice. Trigger points are commonly seen in patients with myofascial pain that can be responsible for localized pain in the affected muscles as well as referred pain patterns. Correct needle placement in a myofascial trigger point is vital to prevent complications and improve efficacy of the trigger point injection to help reduce or relieve myofascial pain. In the obese patients, these injections may not reach the target tissue. In the cervicothoracic spine, a misguided or misplaced injection can result in a pneumothorax. Here, we review an electromyographically guided trigger point injection technique to avoid this potential pitfall. Methods: Using a disposable Teflon coated hypodermic injection needle attached to an electromyography (EMG) machine, a trigger point injection can be performed utilizing electromyographic guidance. This guidance by observing motor unit action potentials (MUAPs) on the EMG screen helps confirm the needle placement to be within the muscle tissue and not in an adipose tissue or any other non-musculature structure. Results: The technique is simple when performed by a pain management specialist who has electromyographic training. Conclusion: This technique helps confirm proper needle placement within the cervicothoracic musculature in an obese patient in whom the musculature is not readily palpated. This, thus, reduces the potential for a pneumothorax by an improperly placed injection. Key words: Trigger point injection, myofascial pain, electromyography