DISCUSSION
Peripheral nerve blocks have recently become a preferable treatment
option for primary headaches’ acute and preventive treatments. Numerous
randomized, controlled studies have shown that the GON block was
effective [4, 8, 9]. Its contributions to patient satisfaction,
daily activities, and treatment costs are too significant to be ignored,
mainly due to improvements in migraine treatments. There were
statistically significant reductions in our study when the first and
third-month values were compared to the pre-treatment values regarding
the days with pain, analgesic use, VAS, and MIDAS scores in 120 patients
in whom we had performed a GON block (Figures 1 and 2).
In many studies, it has been shown that significant improvements
occurred with a GON block, injecting a local anesthetic substance, and
steroids in migraines of resistant patients who were unresponsive to
prophylactic treatment [4-8]. Caputi et al. performed GON and
supraorbital blocks using bupivacaine and determined decreasing headache
severity in 85% of their patients. This study determined significant
pain severity reductions when we compared the periods before and after
the treatment.
The American Headache Society made practical recommendations regarding
peripheral nerve and GON blocks in 2013; however, they stated that a
consensus had not been reached on the amount to be administered and the
repetition frequency since there were not enough randomized, controlled
studies [10]. Numerous studies have been conducted on the
effectiveness and use of the GON block in primary headaches to clarify
such issues and determine the boundaries; however, standardization has
not been yet achieved, and in most studies, different options were
preferred regarding the administration technique, drug preference, and
dosage [9, 11, 12].
Lidocaine and bupivacaine are commonly preferred in peripheral nerve
blocks. We preferred lidocaine in our patients because of its shorter
half-life when compared to bupivacaine. Local anesthetics create a
reversible blockade in sodium channels of nerve fibers and provide
efficient control by causing depolarization in demyelinated C-fibers and
myelinated A-fibers, which play roles in pain signal transmission. Since
pain control’s duration is longer than the administered local anesthetic
agent’s half-life, pain control has been considered to be associated
with central modulation. Corticosteroids may be preferred for treatment
from time to time to prolong the block duration. Even though less common
in chronic migraine patients, corticosteroids have been preferred
particularly for the treatment of cluster headaches, and they were
determined to be more efficacious [13]. The corticosteroids’
long-term effects are unknown. Corticosteroids are known to inhibit
pro-inflammatory cytokines’ synthesis and release and suppress
inflammation. Moreover, they provide efficient pain control through
membrane stabilization, reversible inhibition of nociceptive C-fibers,
and modulation of nociceptive input to the substantia gelatinosa [5,
14].
Numerous studies have been conducted on local anesthetics’
effectiveness, superiorities to each other, and combination treatments
with steroids. Gül et al. compared bupivacaine and saline and determined
that the 2-month and 3-month VAS scores were significantly superior to
those of the placebo group [15]. When 0.25 ml of lidocaine 0.5% was
compared to 2.5 ml of bupivacaine 0.5% and methylprednisolone, it was
determined that their efficacies were not superior to each other.
Studies on steroids’ addition to treatment have shown that steroids did
not contribute [12, 16, 17].
There is no standardization regarding unilateral or bilateral GON block
applications, and the block is performed on an optional basis. The study
comparing unilateral and bilateral GON blocks’ efficacies reported no
difference between them [18]. We preferred to perform bilateral GON
blocks and additionally the supraorbital nerve block in our method.
Single block or repeated nerve blocks? Numerous studies have reported
that repeated nerve blocks were more effective than single blocks [16,
18-21]. In our clinic, we preferred to perform six sessions of blocks
in total, once a week in the first month and once a month in the second
and third months. The treatment responses of patients in whom a GON
block was performed together with prophylaxis were compared to those in
whom only a GON block was performed, and no significant differences were
determined between the two groups regarding the headache duration and
attacks. Most of our patients had been receiving prophylactic treatment,
and some of them stated that their requirement for prophylactic
treatment had decreased in later treatment stages, and they had quit
their medications. We determined significant reductions in patients’
analgesic requirements in the course of treatment (Figure 3). The GON
block is reliable for patients; however, vasovagal syncope, temporary
numbness at the injection site, and particularly when combined with
steroids, alopecia, and cutaneous atrophy were reported [9]. No
significant side effects were observed during and after the GON block in
our study.
Our study had various limitations. Since the study data were collected
through retrospective chart review, we could not reach some data, and
our study’s data were confined to the records only. Our study’s
shortcomings were its small sample size, absence of a control group, and
our inability to follow up the patients for a longer duration.
Prospective, randomized, and placebo-controlled future studies with
longer duration and larger sample sizes are required.