DISCUSSION
Myofascial pain syndrome is more prevalent than it is assumed to be.
Furhermore, its occurrence should be considered in HSP rehabilitation as
a primary etiology or sometimes accompanying the primary
pathology.15 Studies have described it as an
underdiagnosed issue since it is frequently overlooked. HSP has a
complex mechanism in which nociceptive and neuropathic pains play a
role.16 Conditions such as muscle imbalance, postural
disorders, immobilization, and emotional stress in stroke patients may
cause both the emergence of MTrP and the activation of latent MTrP in
the shoulder region.6,13 As a result, a multimodal
treatment approach is offered by both attempting to restore the
neurological deficit and targeting MTrP. In this context, this study
aimed to evaluate whether combining DN treatment with conventional
rehabilitation contributes to improving pain, joint range of motion, and
functionality parameters and clarify the significance of MTrP in HSP.
While designing the study, we aimed to evaluate the parameters of pain,
joint range of motion, and functionality at the end of three months.
Therefore, the included patient population was clearly standardized and
the frequently affected muscles in the shoulder girdle and periscapular
region were targeted. The results showed that DN treatment did not
provide an extra advantage on pain and functionality in HSP in the
subacute period but contributed to improving joint range of motion both
in the acute and subacute periods.
The prevalence of MTrP is higher in patients with HSP compared to that
in the healthy population.6 Moreover, studies have
emphasized the importance of both latent trigger points and active
trigger points in HSP and stated that the number of MTrP may be
correlated with pain and dysfunction.6 Among the
studies examining MTrP in HSP treatment, there are some current ones
using the myofascial release technique, local anesthesia, and DN
treatments.12-14,17 In general, these studies combined
MTrP therapy with conventional rehabilitation. Indeed, evaluating MTrP
treatment as the primary treatment would be an incomplete approach for a
complex pathology like HSP.
Neurophysiological mechanisms leading to anti-nociceptive effects on the
myofascial trigger point and central nervous system can be initiated by
DN treatment.18 Spinal dorsal horn activity is
modulated by eliminating the source of peripheral nociception, and
peripheral and central sensitization can be reduced by activating
central inhibitory pain pathways.18,19 Moreover, with
the elimination of the pain-spasm-pain vicious cycle, pain relief and
improvement in joint range of motion is achieved, contributing to the
biomechanics of the region.20,21
There are a limited number of publications on DN treatment for HSP.
DiLorenzo et al., for instance, administered conventional rehabilitation
to one group and DN treatment combined with conventional rehabilitation
to the other group of patients with HSP.14 The results
showed that there was a statistically greater improvement in pain level
in the acute period in the DN group. Similarly, in our study, there was
a greater improvement in posttreatment pain level in the DN group.
However, this difference was no longer significant in the third month.
In the studies of Dilorenzo et al., the lack of standardization in
applying DN to the muscles was a disadvantage; while there were many
applications on some muscles during the conventional treatment, some
muscles received only two sessions.
Another point is that the aforementioned study evaluated functionality
with mobility, and superior results were observed in the DN group. On
the other hand, in our study, more objective and specific assessment
scales for the upper extremity were used, and more improvement was
observed in the DN group after treatment. However, there was no
difference between the groups on the third month. Previous studies have
reported that latent MTrPs also affect functionality in patients with
HSP, and the fact that latent MTrPs were not treated in our study may
have led to this result.6
Mendigutia-Gomez A. et al. found that the combination of conventional
rehabilitation and single-session DN treatment reduced HSP more in the
acute period compared to only conventional
rehabilitation.12 While the results after treatment
were similar in our study, this difference was not observed in the third
month. The rehabilitation in our study, unlike the mentioned study, was
in the form of a protocol covering a certain period for each group in
accordance to the literature. Similarly, there were three sessions based
on the general application of DN in sessions. Another important
dissimilarity in our study is the demonstration of data for the subacute
period. Furthermore, the duration of shoulder pain of the patients was
not stated in the aforementioned study. The fact that the participants
in our study had an average of six months of shoulder pain and that this
condition contributed to the mechanisms of chronic pain may also explain
the unresponsiveness to MTrP treatment in the subacute period. Indeed,
MTrP is an entity that has the potential to become chronic regardless of
the etiology and is easier to diagnose and treat in the acute
phase.22
MTrP treatment using local anesthesia has similar effects as using DN
and its effectiveness in reducing pain is independent of the injected
drug.23 From this perspective, Liporaci FM et al.
administered local anesthesia to MTrPs in HSP, and the results indicated
that there was a decrease in pain intensity after treatment, while no
change was observed at the end of the four-month
follow-up.13 On the other hand, abduction measurements
increased significantly. The disadvantage of this study was that
conventional rehabilitation was not used in the treatment and there was
no control group. In contrast, our study indicated predominance in the
flexion and abduction movements compared to the control group at the end
of the third month. Therefore, it can be concluded that MTrP treatment
for HSP is more effective on improving joint range of motion when
combined with conventional rehabilitation.