Strengths and weaknesses
The topic of pain control in gynaecological procedures is a difficult
topic to study and a significant strength of this study lies in the
parallel qualitative investigation of patient attitudes and experiences.
The experimental arm of this study achieved a 100% follow-up rate from
baseline and was strengthened through the use of standard methods of
control, including randomisation, stratification and minimisation
techniques ensured comparability at baseline and minimising selection
bias. Numeric Rating Scale is known to be a validated measure of pain,
is easy to use, has high compliance rates and detects meaningful changes
in pain and anxiety25.
One limitation of the intervention was that the video was made from a
standing rather than prone perspective; the field of vision during
hysteroscopy was such that the entire content of the virtual environment
could not be explored and this might be addressed by development in the
VR technology. Restriction of movement of the patient whilst engaging
with the video in light of the nature of the diagnostic procedure could
also limit the degree of immersion. The duration of the video was
shorter than the length of the procedure for two patients, requiring the
video to be restarted. This disrupted the immersion experience and
required the health care assistant to keep a watch on when the video
finished. Despite these limitations, the intervention was found to be
effective in analysis.
The intervention, due to its nature, could not be blinded from the
participants, so demand characteristics related to self-reporting of
outcome scores may have influenced the results. Non-blinding of the
participants could have resulted in patients receiving the VR
intervention underreporting the pain and anxiety scores and those
patients not receiving the intervention to have over-reported the
scores. Additionally, the pain and anxiety scores were measured within
10 minutes of the intervention and were therefore subject to a degree of
recall bias. As prior estimates of standard deviation were not
available, powering the study for any expected effect size was not
possible. However, we detected a relatively large significant difference
between groups and therefore avoided the risk of a type 2 error. Our
findings will inform sample size calculations for a future full-scale
trial.
To our knowledge, this is the first randomised evaluation of
feasibility, effectiveness and acceptability of a virtual reality
intervention in gynaecology. However, a trial protocol has been
published for a randomised controlled trial for VR analgesia for women
during hysterosalpingograms and results will be
forthcoming.34