Ultrasound guided axillary nerve block compared to hematoma block for analgesia in patients with closed reposition of distal forearm fractures.

Fractures of the forearm are very commonly seen in the Emergency Department
(ED) and mostly comprise the distal radius and ulna. Distal forearm fractures
have an incidence of 278 per 100.000 patient years. Court-Brown found a
incidence of distal radius fractures of 195 per 100.000 patients. Distal radius
fractures alone account for 17.5-46% of all skeletal fractures observed in
primary care setting. And as distal radius fractures are considered as an
osteoporotic fracture, the incidence will increase with our ageing population.
The majority of distal radius fractures are treated conservatively
(non-operatively). However, up to half of these conservatively treated
fractures require closed reposition for better union and functional outcome.
This is a painful procedure and adequate pain management is of utmost
importance, both for reducing pain as well as achieving optimal clinical
outcome.
There are several interventions for pain management in these patients, amongst
which general anaesthesia, procedural sedation and analgesia, intravenous
regional anaesthesia, peripheral nerve block (PNB) or local analgesia such as
the fracture haematoma block (FHB)). Of these, the latter is most commonly used
in the ED and is advised by the current Dutch trauma guideline. Interestingly,
whether or not this is the superior method is still unknown due to scarcity of
scientific evidence. However, the FHB is known to be a painful procedure, with
unsatisfactory success rates (a mean visual analogue scale (VAS) of 5.53 (SD
3.67)) and with outcomes very dependent of the individual physicians* skills.
Other options such as procedural sedation and analgesia (PSA) or general
anaesthesia are time-consuming procedures, require expensive resources, and
poses unnecessary risks to the patient such as hypotension or hypoxia. Since
the use of ultrasound in EDs is more and more available, ultrasound-guided
peripheral nerve blocks for pain control are a realistic and safer option. A
recent study comparing ultrasound-guided peripheral nerve blocks (cubital nerve
block (CNB) and axillary nerve block (ANB)) with FHB found significant
reduction in pain perception, especially in the ANB block. However, this study
did not investigate some important secondary factors in an ED such as
procedural time, reposition time, re-reposition, quality of reposition and
other resources as personal and financial costs. Feasibility studies for ANB
showed a short time for procedure performance (only 5 minutes) and time to
achievement of analgesia comparable to FHB, indicating good applicability in
the busy ED. Moreover, ANB does not pose patients to a great complication risk
whereas complications such as infection, local nerve injury and local analgesic
systemic toxicity (LAST)) are rare. This especially after the introduction of
ultrasound guidance of peripheral nerve blocks. Most complications are minor
and consist of soreness at injection site and transient numbness, as comparable
with complications seen in FHB and may even be less due to the use of
ultrasound guidance. Furthermore, performing a cubital nerve block (CNB)
involves multiple injections whereas ANB could be performed using a single
injection.
Compared to the more proximal nerve blocks, for example the supraclavicular
brachial plexus and interscalene block, complications such as the risk of
pneumothorax, phrenic nerve paralysis and Horner*s syndrome do not exist
performing an ANB. Compared to the *blindly* performed FHB block, the risk for
an intravascular injection is small, due to the visualisation of the tip of the
needle using ultrasound guidance. Moreover, the injection site is not painful
prior to the procedure due to the existing fracture. Lastly, using a PNB leads
to a better muscle relaxation due to motor loss of distal muscles, increasing
the treatment process and results.

The primary goal of this study is to compare ultrasound-guided ANB with FHB for
analgesia during closed reposition of distal forearm fractures. Secondary goals
are evaluation of feasibility in the ED regarding time and procedure success
rate.

Primary Objective:
The primary objective of this study is to compare ultrasound-guided ANB with
FHB for analgesia during reposition of non-operatively treated forearm
fractures.

Hypothesis:
We hypothesize that ultrasound guided ANB will lead to a clinically significant
pain reduction (>= 2 point reduction on a NRS 0-10 scale) and improve analgesia
to reposition distal forearm fractures compared to the standard FHB.

Secondary Objectives:
Secondary objectives will be used to evaluate the feasibility in the ED and
consists of procedural time and number of attempts for a successful block.

This study is a randomised controlled prospective study performed in the ED of
a teaching hospital (MCL Leeuwarden, Trauma Centre Level II).

A patient with a distal forearm fracture who meets the inclusion and exclusion
criteria will be randomized and allocated to the FHB or ANB group.
The FHB will be performed without ultrasound, as is common practice. The ANB
will be performed using ultrasound, as is common practise:

FHB block procedure
In this blinded technique (as is common practise), after disinfection, the
needle is inserted from the dorsal side to the bone surface and the physician
will search for the fractured area. Then blood is aspired in the cannula as a
sign of the needle tip being in the haematoma surrounding the fracture, and the
anaesthetic 1% lidocaine is injected.

ANB block procedure
After the arm is positioned in a comfortable position, the medial upper arm is
disinfected.
Using a linear probe and sterile ultrasound gel, the anatomic landmarks as the
axillary artery and the nerves are identified, as taught by training of an
experienced anaesthesiologist. Then, the anaesthetic, 1% lidocaine, is being
injected around the identified nerves. An ANB consist of blocking the radial,
median and ulnar nerve and the musculocutaneous nerve. This can be achieved by
a single injection through the skin. It will result in anaesthesia of the
mid-arm to and including the hand. Some emergency physicians are already
practising this technique, some are not. All will be additionally trained.

Regardless of a patient being treated within in our study, fracture reposition
might be necessary as is analgesia prior to this reposition. Both the FHB and
the ultrasound guided ANB are well established methods of analgesia, and used
as common practise. Also lidocaine is well established as a local anaesthetic
agent, used as common practise. Therefore no significant ethical concerns are
found with conduction of the study.
Participants have the possible benefit of a ANB because of possible better pain
reduction, the use of less local anaesthetics (and lesser risk for local
analgesic systemic toxicity (LAST), and the fact that not a wounded area but a
healthy part is anesthetised (better analgesia and less risk of infection). To
our knowledge there are no long-term benefits from participation. The gain for
future patients in the potentially increased pain relief satisfaction far
outweighs the minimal disadvantages of study participation including as a
couple additional questions and maybe some soreness on the infection site on
the upper arm.