2.1.1. Ethical approval
All the procedures performed in this study involving human participants
were in accordance with the ethical standards of the Institutional
and/or National Research Committee and with the Declaration of
Helsinki,1964, and its later amendments or comparable ethical standards.
Approval from the Institutional Review Board of Van Training and
Research Hospital, Van, Turkey, was obtained prior to the execution of
the study (2018/16). Written informed consent was obtained from all the
patients. The study was reported in accordance with the Consolidated
Standards of Reporting Trials statement, and the trial was registered at
clinicaltrials.gov (NCT03790514).
Results
A total of 103 patients (51 treated with a heat-patch and 52 sham) with
renal colic were included in the study. The baseline characteristics
between the two groups did not differ significantly (Table 1). The
dropout rates for the two groups were n =8 (13.5%) and n =7
(11.9%) patients, respectively (Fig.1).
On admission, both groups had similar VAS scores. The changes in VAS
scores over time for the two groups are presented in Fig.2. In the
heat-patch group, 15, 30, 45, and 60min VAS scores were significantly
lower than those in the sham group. In addition, according to the
baseline VAS score, the decrease in pain level in the heat-patch group
at 15, 30, 45, and 60min was statistically significantly higher than
that in the sham group. For both groups, 15, 30, 45, and 60 min VAS
scores and changes in pain severity are provided in Table 2. Fourteen
and six patients in the sham and heat-patch groups, respectively, needed
pain salvage treatment (p =0.01).
There was no statistically significant difference between the two groups
in terms of 15, 30, 45, and 60min Btemp values (p = 0.17, =0.21,
=23, =0.37, and =0.23, respectively). In addition, there was no
statistical difference found at 0 and 15min Stemp values of the two
groups (p = 0.39 and p =0.10, respectively). However, when
Stemp was analyzed between the heat-patch and place groups at 30, 45,
and 60 min, a statistically significant difference was found (Table 3).
Discussion
Nowadays, NSAIDs, paracetamol, and opioids are considered first-line
treatments for renal colic; however, these drugs have many side effects.
Besides, patients cannot directly access these medicines when the pain
starts. Therefore, a simple and safe analgesic method during the
prehospital phase could be useful for patients with renal colic. In this
study, heat-patch treatment performed as a local warming method was
shown to be superior to sham as an alternative treatment method for the
treatment of renal colic. The changes in VAS scores were statistically
significantly and clinically relevant.
Mechanosensitive receptors that are stimulated by mechanical induction,
such as lithiasis, are the receptors that innervate the kidney and
ureter mainly (16). However, unlike somatic pain, visceral pain is
generally diffuse and poorly localized. It is also referred to as the
body wall, where viscerosomatic convergence is the key in the central
pain pathways. Visceral afferents are placed in only a few of the
afferent inflows of the dorsal horn and viscerosomatic convergence in
the dorsal horn, and supraspinal centers are very well documented.
Therefore, visceral mechanosensitive receptors converge with heat
afferents, raising from the body wall, and may change the central
viscerosensory response in the dorsal column (16,17). This hypothesis
may explain the pain-relieving impact of body heating in this study.
Another hypothesis that plays a role in reducing pain with the effect of
heat may involve increased intravascular prostaglandins, bradykinin, and
histamine secretion as a result of the increased blood flow to the
region led by heat-patch treatment (12-14,15).
In a preclinical trial, sympathetic blockading was found to be
associated with attenuated visceral nociceptive responses. Pertovaara et
al. demonstrated that following sympathectomy, visceral nociceptive
responses decreased in rats (18). In addition, Kober et al. treated
patients with renal colic by active warming of the lower back region and
showed high sympathetic activity in patients with pain and urolithiasis
(12). These findings highlight the role of the sympathetic nervous
system in the perception of visceral pain.
Outside any situation of urolithiasis, local heat was recommended as a
way of reducing the pain of trauma patients in the emergency department.
In a study conducted by Bertalanffy et al. on patients with acute pelvic
pain, where the other reasons for pelvic pain excluded gynecological
causes, active heat treatment (electric blanket) was found to be a
significantly effective method in reducing pelvic pain (19). Similarly,
a study conducted by Nuhr et al. on patients with acute back pain, the
pain was found to be reduced more in active heat treatment areas
compared to passive heat treatment areas (15). In a randomized
controlled study performed by Kober et al. on patients with renal colic,
it was shown that VAS scores were statistically decreased in patients
receiving active heat treatment compared to those receiving passive heat
treatment 12. Similar to these studies, in our study,
we also showed that in the heat-patch group, Stemp values increased
statistically, and the decrease in VAS scores was higher in the
heat-patch group than in the sham group.
There are some inherent limitations in this study. The major limitation
is the absence of comparison of heat-patch treatment and an analgesic
agent. In addition, the fact that the patients received their actual
treatment late could be considered a limitation; however, we were able
to protect them from the possible side effects of the medications to be
given. Another limitation that must be noted is that although we used
patches that waited at room temperature for at least 24 h before the
application in the sham group, we were aware that these patches would
never reach the Stemp values of the study groups. However, no patient
reported any heat-related complaints during the study. Last but not
least, we did not include distal ureter stones, as the pain referred
from these stones is mediated by the ilioinguinal and genitofemoral
nerves, which radiate the pain to the groin, testicle, or labia majora.
Conclusions
Heat-patch treatment appears to be an ideal candidate to reduce pain in
patients with urolithiasis, especially during the prehospital phase. As
it does not contain any drug and has no side effects, healthcare
professionals are not required for the application. We recommend that
heat-patches be used at least as the primary treatment option for
patients with urolithiasis before the actual treatment (if needed).