Discussion
This prospective randomized controlled study included 36 patients
diagnosed with De Quervain tenosynovitis. Patients were evaluated with
VAS and DHI at baseline then at 1 and 12 months after the end of the
treatment. Hand functions seemed to be improved at the first and 12th
month follow-up examinations in both groups. The 12th month follow-up
VAS scores were lower in the NT group than in the control group
therefore, and there was no significant difference in hand functions
between the two groups in long-term follow-up. In the NT group, no
patient had Finkelstein test positivity at the first month follow-up,
and the positivity rate at 12 months was 16.7%.
Pain is the most common problem in accomplishing daily living activities
for patients with De Quervain tenosynovitis. The primary goal of
treatment of tenosynovitis is pain relief and regaining hand functions.
The effectiveness of treatment in De Quervain tenosynovitis has been
previously evaluated in many studies. In a retrospective study of 222
hands, which investigated the effectiveness of corticosteroid injection,
treatment success was achieved in the first 2 injections in 73% of
patients in total. In 26% of patients, corticosteroid injection
treatment failed or there was a need for surgery.2
In another study, Lane et al. reported 76% treatment success in a study
population treated with corticosteroid injection and there was need for
surgery in 4% of the patients.15 In the current
study, the treatment success rate in the short and long-term follow-up
after treatment was >80% in the neural therapy group.
When viewed in terms of adverse effect profile, in previous studies that
have paid particular attention to the side-effects of corticosteroid
injections, the authors have reported difficulty in maintaining blood
glucose regulation for a few days after the injection, especially in
patients with diabetes mellitus. 16
Another study investigating the effectiveness of corticosteroid
injections reported adverse effects such as skin atrophy and
hypopigmentation at a high rate of up to 60% even in ultrasound-guided
injections. 17 Therefore, it has been emphasized that
corticosteroid injection should not be considered as completely free of
adverse effects. In the current study, no adverse effects were detected
in any patient in the neural therapy group.
In a study in which the long-term treatment efficacy for De Quervain
tenosynovitis was evaluated, 13.7% of the patients required repeated
injections during the mean follow-up period of 54 months, 5.9% had a
partial response, and 2% had no response. 18 In the
current study, the treatment success rate in the NT group at 12 months
was 83%.
Acupuncture is a rarely used treatment modality for De Quervain
tenosynovitis and few studies have been conducted on this subject. In a
study which evaluated the short-term effectiveness of corticosteroid
injection versus acupuncture treatment, there was reported to be no
superiority of one method over the other in the short term in respect of
pain. 6 However, some authors have stated that
acupuncture should not be recommended as a priority treatment in De
Quervain tenosynovitis. 19 Comprehensive long-term
results investigating the effect of acupuncture on hand functions and
pain are not available.
Recent studies have shown that De Quervain tenosynovitis is not just
stenosing of the tendons but also has a tissue inflammation
aspect.20 Local anesthetics have anti-inflammatory
effects in addition to nerve blocking and membrane stabilizer
effects.21 Therefore, local injection of procaine can
provide an anti-inflammatory effect and reduce edema, resulting in
reduced stenosis in the fibro-osseous canal. This could explain the
decrease in pain and functional improvement in the current study.
To the best of our knowledge no previous study in the literature has
evaluated the
efficacy of local anesthetics in the treatment of De Quervain
tenosynovitis, but another issue that should be noted is that local
anesthetics have been added to the injection solution with
corticosteroids in many studies, because as stated above, local
anesthetics also have anti-inflammatory activity.4,6,18,22 Therefore, corticosteroids alone may not be
responsible for all the pain relief and functional improvement
demonstrated in these studies.
Trigger points are described as palpable and hypersensitive spots in
muscles, which may lead to the referred pain. 23,24Trigger point injection contributed to the treatment in the current
study to eliminate the effect caused by referred pain. Nazlıkul et al.
reported that local anesthetic injection to trigger points of the
piriformis muscle decreased pain and improved function in patients with
low back pain. 25
In the human body, the sympathetic system has an effect on pain, by
affecting tissue perfusion. Decreased perfusion causes hypertonus of the
muscles and hyperalgesia. Neural therapy can regulate the autonomic
nervous system and restore decreased blood flow to tissue by blocking
the pathological signals of the sympathetic system.26In addition it has also been shown that the sympathetic nervous system
has a pathological memory responsible for musculoskeletal
pain.10,27 This pathological memory, also known as
neuronal signature, is considered to start when pro-inflammatory
cytokines released from sympathetic nerve endings cause nociceptive
stimulation due to tissue damage. The sympathetic efferent-nociceptive
afferent connection, which occurs as a short circuit over time, may
result in central sensitization. If this system is activated with
continuous stimulation at the spinal cord and brain level,
neuroplasticity develops and pathological pain memory occurs.
This is the most important mechanism of neural therapy approaches.
However, the pathophysiology of chronic pain still remains unclear. It
is known that chronic nociceptive stimulation leads to overactivation of
central sensory transmission and causes central sensitization.
Nociceptive transmission at spinal-supraspinal levels and sympathetic
activity in a wide dynamic range of neurons can be stopped by membrane
stabilization that is achieved by local anesthetic injection.26,28 The pain-free condition seen in the long-term
follow up of the patients who underwent neural therapy may have been
caused by the effect of local anesthetics to erase the pathological
memory in these sympathetic system neurons and prevent nociceptive
transmission at spinal-supraspinal levels. Similarly, this mechanism
seems to be effective in Finkelstein test negativity in long-term
follow-up.
Stellate ganglion injection may alleviate the pain by breaking this
vicious circle.29,30,31 The decrease in pain and
improvement in hand function may have been achieved by these mechanisms
in the NT group patients.
Procaine was used as the local anesthetic in this study. The
anti-inflammatory and autonomic nervous system regulatory effect of
procaine can be considered responsible for the decrease in pain and
improvements in functionality. No adverse effects were seen in any
patient.
There were some limitations to this study, primarily the low number of
patients. Further studies with a greater number of patients will provide
more valuable results. Another limitation of the current study was the
non-blinded method, so it can be suggested that further studies should
be performed double blinded.