The intertransverse process (ITP) block is a new ultrasound-guided peripheral nerve block
modality designed for peri- and postoperative pain amelioration for patients undergoing
surgery on the thoracic wall. The modality mimics the well-known thoracic paravertebral block
but, potentially, with a significantly lower risk of adverse events. However, evidence for
the ITP block efficacy and the clinical applicability, e.g. the number of injections,
dermatomal coverage etc., is still sparse and needs further investigation.
In this noninferiority, short-term, randomised, blinded, procedure-related crossover trial we
will further investigate the ITP block in healthy volunteers to see whether it is possible to
reduce the number of injections from three to one and substantiate the number of
anaesthetised dermatomes with either modality as the primary outcome. Secondary outcomes
include sensory mapping of the thorax, non-invasive thermography, changes in non-invasive
blood pressure and satisfaction with block application.
At Zealand University Hospital, twelve healthy volunteers will be randomised to receive
either a single injection or multiple injection blockade with long-lasting local anaesthetic.
All twelve participants will, on day one, receive active blockade with the well-known
marketed drug Ropivacaine 7.5mg/ml, and all participants will receive 21 ml; that is six
participants receiving 1x21ml and six participants receiving 3x7ml. The six participants
receiving 1x21 ml will also receive two sham injections to ensure the blinding. No placebo is
used. On day two the intervention is crossed over and the participants will receive the other
modality. Within the following hour after block application, relevant standard cutaneous
testing is performed; pinprick and cold sensation test for dermatomal coverage, the
anaesthetised skin area is pen marked on the thorax and photo documented, thermography to
measure temperature differences between each hemi thorax (blocked side vs. non- blocked side)
and standard non-invasive blood pressure measurements are performed.
After 60 minutes of relevant testing the trial ends and the participant are free to leave the
hospital 2 hours after block application if no adverse events are recorded. With such series
of test procedures, we will generate new knowledge of the ITP block before future patients
undergo breast cancer surgery.