Carpal tunnel syndrome (CTS) is the most common peripheral compressive neuropathy of the
upper limb, consisting of involvement of the median nerve at the level of the carpal tunnel.
It has a prevalence of 7% to 16% in the United Kingdom adult population, while in the United
States between 400/500 thousand patients are treated surgically, with an annual economic cost
exceeding $2 billion.
A variety of treatments are available according to the stage of the pathology, including
splinting, kinesic therapy, ultrasound, non-steroidal anti-inflammatory drugs, systemic or
local corticosteroids , as well as surgical treatment in patients who do not respond to
previous options.
Corticosteroid infiltration is one of the most widely used methods for the treatment of
idiopathic carpal tunnel syndrome (ICTS) in mild and moderate stages, and short-term
symptomatic improvement is reported in the literature, although the optimal dose and drug
used for the same is varied in the various published studies, and is still a matter of debate
in the literature. Betamethasone has greater anti-inflammatory power and a longer duration of
action at the same equivalent dose than other corticosteroids used in the treatment of CTS
(prednisolone, methylprednisolone, triamcinolone, cortisone).
In addition, ultrasound-guided local infiltration helps prevent iatrogenic injury compared to
anatomical repair-guided infiltration. Studies show improvement in scores assessing
symptomatology, although there is no strength in determining improvement in functional and
electromyographic assessment. The rate of adverse reactions with this technique is low,
reported to be <0.1% for major complications, and 2% for minor complications.
The effectiveness of local and systemic corticosteroids has been demonstrated, but whether
there is any difference in clinical improvement in patients between one route of
administration versus the other remains a question mark.
Rationale for the study In the institution, both intramuscular and ultrasound-guided
administration of systemic corticosteroids are part of standard practice, with systemic
administration indicated in the trauma department and ultrasound-guided administration in the
rheumatology department. Although, given that these are standard practices, retrospective
evaluation of the cases could answer the objective of this study, in the review of the cases
the investigators found an imbalance in the type of CTS in the cohorts treated in each
department. This is mainly due to the fact that in the orthopaedics service most patients
consult for CTS and in the rheumatology service, due to the speciality itself, there is a
large proportion of patients with secondary CTS (rheumatoid arthritis, juvenile arthritis,
gout, etc.). Because of this, and to avoid patient selection bias, the aim of this study was
to compare the efficacy of systemic (intramuscular) corticosteroid treatment with local
infiltration in ICTS.
The same efficacy of systemic administration (intramuscular) as local administration (via
ultrasound-guided infiltration in the carpal tunnel) should reduce the cost of treatment and
the complications associated with local injection. In addition, it would allow effective
treatment in centres where there are no specialists trained in the ultrasound-guided
infiltration technique, allowing greater generalization of the treatment.
The investigator's hypothesis is that intramuscular corticosteroid infiltration (systemic
effect) offers the same results in terms of symptom improvement as locally applied
corticosteroids under ultrasound.
The primary objective is to compare the Boston score in patients treated with systemic
(intramuscular) versus local infiltration corticosteroids in mild and moderate ICTS at 1.5
months, 3 months, 6 months and 12 months post-procedure.
The exploratory objectives are to describe adverse reactions associated with the route of
administration and to compare the pain at the site of application associated with both
methods, in relation to the technique used, measured with the Visual Analogue Pain Scale
(VAS).