SUBJECTIVE DATA DISCUSSION

Both the Visual Analogue Scale and Vernon-Mior Neck Pain and Disability Index showed improvements over time for group 1 and group 2. Self-assessment questionnaires play a vital role as a measurement for determining the outcome of a treatment (Gervitt, Hobbs, McCarthy and Silcocks, 2007). A review of literature revealed a positive correlation between the pain scores reported with the Visual Analogue Scale

66 and self-reported disability using the Vernon-Mior Neck Pain and Disability Index (Hermann and Reese, 2001).

Receptors (particularly pain receptors) are located within the human body tissues with a function of projecting stimuli to the pain center, the thalamus, within the brain, pain receptors (free nerve ending) generate and transmit the pain impulse via a- delta and C pain fibers (peripheral nerves), as well as via the lateral spinothalamic tract within the spinal cord (Melzack and Wall, 1996).

Stimulation of the skin receptors transmits nerve impulses to three spinal cord system: substantia gelatinosa cells within the dorsal horn of the spinal cord, dorsal column fibers which transmit the impulse to the brain, and the initial transmission (T) cells within the dorsal horn of the spinal cord. With the afferent impulse prior to it reaching the T cells, the dorsal-column fibers activate selective processing within the brain and thus function to have an impact on the gate control system, and lastly the T cells which activate neural action mechanisms. Interaction between the three explained systems, give rise to gate control therapy of pain (Melzack and Wall, 1996).

With regards to the pain gate theory, pressure receptors are more thickly myelinated and notably longer as compared to pain receptors and pain fibers. Therefore, pressure receptors have the ability to transmit pressure stimuli quicker that of pain receptors, thus facilitating closure of the gate to pain stimuli (Tsao, 2007).

Group 2 showed greater improvement of pain over time based on the subjective data obtained. Dry needling is also referred to as intramuscular stimulation, and is an invasive technique in which an acupuncture needle is inserted into the skin and muscle (Dommerholt and Fernandez-de-las-Penas, 2013).

Many physical therapist and other clinicians have adapted a contemporary pain management approach and incorporate graded exercise, restoration of movement and posture and psychological perspective into the examination, assessment and therapeutic interventions of patients presenting with pain complain (Hodges and Tucker, 2011). The effect of trigger point dry needling cannot be considered without this broader biopsychosocial mode (Gerwin and Dommerholt, 2006). Trigger point dry needling must

67 be approached from a pain science perspective, as it is no longer sufficient to consider trigger point therapy strictly as a tool to address local muscle pathology (Fernandez-de- las –Penas, Dommerholt, 2013).

As Moseley (2003) pointed out, nociceptive mechanisms that contribute to threating information should be treated, where possible (Moseley, 2003). Frequently, trigger points are a constant source of nociceptive input especially in persistent pain conditions (Ge, Wang, Fernandez-de-las-Penas, 2011) and it follows that removing such peripheral input is indicated and consistent with the concepts of Melzack‟s neuromatrix (Melzack, 2001). In addition to their contribution to nociception, trigger points can contribute to abnormal movement patterns (Lucas, Rich, Polus, 2010).

This improvement for dry needling is confirmed by Travell and Simons (1999), who stated that the therapeutic effect of dry needling is to mechanically disturb the trigger point. Due to trigger points having a dysfunctional motor end plates and causes axon denervations distally when the needle hits the trigger point. This is said to trigger specific changes in the cholinesterase at the endplate as part of normal muscle process (Dommerholt et al, 2013).

Improvements and statistically significant change occurring based on the Vernon-Mior Neck Pain and Disability Index scores, require both clinical and evidence-based explanations for not only the reduced pain awareness of the participant but also the decrease disability associated with the pain.

A study was performed in 2001 to investigate the relationship between impairment, functional limitations and the disability seen in patients presenting with cervical spine disorders. Cervical spine impairments included a decrease active cervical spine range of motion or muscle contraction force. Functional limitations included the inability to actively move the cervical spine into a specific plane of movement. Incapability of performing daily requirements/tasks was considered a disability. The result of the study supported the links between observed impairments and the ability of an individual to function and his/her self-reported level of disability (Hermann, Reese, 2001).

68 Therefore disabilities can be improved by limiting impairments and functional restrictions. Manual therapies which aim to restore a full optimal length of the involved muscle will ultimately cease the chain of events which occur and therefore improve impairments and restrictions. Approaching the full length of a sarcomere will decrease the interaction of actin and myosin leading to decrease contractile activity, decreased metabolic demand and increased metabolic supply (Travell and Simons, 1999). This therefore will account for a greater improvement on the disability index portion of the Vernon-Mior Neck Pain and Disability Index score.

Both groups had clinical improvement based on the Vernon-Mior Neck Pain and Disability Index. Input from muscle nociceptors appears more effective at inducing neuroplastic changes in wide dynamic range dorsal horn neurons than input from cutaneous nociceptive receptors (Wall and Woolf, 1999). Several studies demonstrated that trigger points activate the anterior cingulate cortex (ACC) and other limbic structures, but suppress hippocampal activity (Niddam, Chan, Lee, 2007). Increased activity in the ACC is common in chronic pain conditions and is even present when pain is anticipated (Longo, Iannetti, Mancini, 2012). When treating patients with dry needling techniques, it is imperative to avoid creating the impression that local muscle pathology would be solely responsible for the persistent pain (Puentedura and Louw, 2012). Rather than explaining trigger point as a local pathological or anatomical problem, it makes more sense to focus on the nociceptive nature of trigger points and their role in perpetuating central sensitization; persistent prepheral nociseptive input increases the sensitivity of the central nervous system (Coppieters, Alshami, Hodges, 2006).

Statistically, the improvements were statistically significant for group 1 and group 2 over time according to their intragroup analysis.

Dry needling is said to cause an increase of blood flow to the area of the trigger point which then flushes the area of excess calcium and that in turn decreases the sustained muscle contraction therefore decreasing pain experienced (Travell and Simons, 1999). Ischaemic compression intentionally temporarily decrease the blood supply in the myofascial trigger point area in order to increase local blood flow, this lead elimination of

69 waste products, therefore increasing the local oxygen supply and allowing the affected tissue to heal (Arnau-Masanet, Barrios-Pitarque, Bosch-Morell, Montanez-Aguilera, Pecos-Martin and Valtuena-Gimeno, 2010). This therefore explains the mechanism whereby ischaemic compression reduces pain which therefore substantiates the statically significant improvement seen for group 1.

Therefore, both ischaemic compression (Arnau-Masanet, Barrios-Pitarque, Bosch- Morell, Montanez-Aguilera, Pecos-Martin and Valtuena-Gimeno, 2010) and dry needling (Travell and Simons, 1999), have the ability to increase local microcirculation and to improve oxygen supply to the hypoxic cells. This therefore can account for the statistical improvements obtained over time for both group 1 and group 2 (intragroup analysis).