Moreover, Gerwin and Dommerholt (2006) state that DN is not considered as a precise approach and is not suitable for every patient. There has always been a debate whether or not DN should be considered a part of acupuncture which is based on traditional Chinese medicine. According to Amaro (2007), DN techniques are performed “with the same solid filament needles acupuncture practitioners are using, but dry needling does not require knowledge of the theoretical foundations of acupuncture”. Dommerholt et al. (2006) state that some countries accept in their policy that IMS falls within the scope of physical therapy while others do not. According to them, the DN techniques include different models such as the radiculopathy model, the trigger point (TrP) model, and the spinal segmental sensitization (SSS) model. Superficial DN works under TrP model. deep DN needs both TrP and radiculopathy models. while, injection therapy works under TrP and SSS models.
Radiculopathy model. The radiculopathy model was first put forth by Dr. Chan Gunn and is based on Cannon and Rosenblueth’s Law of Denervation. According to this model, it is always the peripheral neuropathy or radiculopathy that causes the myofacial pain syndrome (MPS). If there is a free flow of nerve impulses, the innervated structures function correctly, otherwise these innervated structures become supersensitive. According to this model, the best treatment points are located near the motor muscles. This model always remained limited to the hypothetical stage. According to Dr. Chan Gun’s research (as cited in Dommerholt et al., 2006):
Relative minor injuries would not result in chronic pain without prior sensitization of the nerve root is inconsistent with many current neurophysiological studies that confirm that persistent and even relatively brief nociceptive input can result in pain-producing plastic dorsal horn changes.
Trigger point model. This model basically deals with MTrPS.