What is the study title?
Full Study Title
Feasibility study of A Randomised Single Blinded Laryngeal Reinnervation versus Type I
Thyroplasty in Unilateral Vocal Fold Paralysis Patients at the Royal National Throat Nose
and Ear Hospital
Short Study Title
Laryngeal Reinnervation versus Type I Thyroplasty
What is voice box weakness and why is the study necessary?
Vibration of two vocal cords in the voice box produces voice. One sided weakness of the
voice box is called Unilateral Vocal Cord Paralysis (UVCP). It is due to injury to the nerve
that controls its movement. One of the causes of the injury is thyroidectomy (an operation to
remove thyroid gland)(Figure 1). Patients with UVCP have weak voice and maybe
swallowing problems which may cause lungs infection. They have problems in
communicating with friends, colleagues and customers which may affect their lives and jobs.
Therefore, restoring a strong voice is very important. The way to treat this problem is by
doing an operation. The two most promising operations are nerve rewiring (reinnervation)
and thyroplasty. Both types of operations have their own advantages and disadvantages. We
do not know which of these methods is better. There are no published studies to compare
these two operations so far. Therefore, this study is important to find out the best treatment to
patients having this problem.
Thyroidectomy scar
Figure 1
What is Nerve Rewiring (laryngeal reinnervation)
Nerve rewiring (laryngeal reinnervation) is to improve the strength of the muscles in the
voice-box and is carried out under general anaesthesia. A small cut is made on the
neck(Figure 2). During the operation, the nerve supplying the voice box will identified and
will be connected to the nerve which supplies one of the muscles on the front of the neck
(Figure 3). Any changes in the way this neck muscle works after the operation are not
noticeable. At the same time, a small amount of fat will be taken from near the belly-button,
and injected into the weak vocal cord using a telescope through the mouth (Figure 4). The fat
injection is not permanent, but will give some useful voice improvement while we wait for
the result of the nerve rewiring to take effect. The operation lasts about 2 hours.
View of the side of the neck
(the line shows the cut in
the neck for nerve rewiring
operation)
Figure 2
VOICE BOX FRAME WORK
Wind pipe
The injured part of
voice box nerve left
behind
Rewiring site between the
uninjured voice box nerve and the
other nerve that supplies other
muscle of the neck
Figure 3: Diagramatic picture of nerve rewiring operation
Crumley, R.L., Izdebski, K. & McMicken, B., 1988. Nerve transfer versus Teflon injection for vocal
cord paralysis: a comparison. The Laryngoscope, 98(11), 1200-1204.
Figure 4 : A telescope through the mouth for the fat injection to the weak
vocal cord
What is thyroplasty?
Thyroplasty is carried out under local anaesthesia, with some medicine that makes the patient
sleepy and relaxed. A small cut is made on the neck (Figure 5). A small block made from a
safe type of plastic will be placed into the side of the voice box, and this pushes the weak
vocal cord into a position which is better for speech and swallowing (Figure 6). The patient
would not have pain during the operation and would not remember the operation. The
operation lasts about 1 hour.
Voice box
Figure 5: This picture shows site of cut on the neck
Small block (implant made of
silicone)
Figure 6: This picture shows a voice box seen from above view. A small
block placed into the side of the voice box.
Montgomery, W.W., Blaugrund, S.M. & Varvares, M.A., 1993. Thyroplasty: a new approach. The
Annals of Otology, Rhinology, and Laryngology, 102(8 Pt 1), 571-579
Who are eligible to be included in the study?
a)
Patients who sustained recurrent laryngeal nerve palsy of at least 6 months
b) Age from 18 to 70 years old.
c)
able to provide informed consent
d) UVFP patients who failed voice therapy
Who are not eligible to be included in the study?
a)
Patients who sustained recurrent laryngeal nerve palsy within 6 months of recruitment
b) Patients who sustained high vagal injury
c)
Patients with cricoarytenoid fixation (CAJF)
d) Multiple lower cranial nerve paralyses
e)
Anatomical or physiological barriers to flexible nasopharyngolaryngoscope insertion
f)
Patients with chronic lungs problem such as chronic obstructive airway disease
g) Patients with vocal fold lesions such as polyp, cyst or oedema.
h) Previous surgical intention for medialisation except completely reabsorbable material
after reabsorption.
What does the study involve?
The UVCP participants are put into two groups. One group will get reinnervation and the
other group will get thyroplasty. The results are compared to see if one is better. To try
to make sure the groups are the same to start with, each patient is put into a group by chance
(randomly, so this is called ‘randomisation’).The patients have a 50-50 chance undergoing
either operation. Before and after the operation the doctor will:
a) record the voice
b) record the vocal cord movements using a camera connected to a telescope passed
through the nose (Figure 7)
c) measure the swallowing
d) measure how well the muscles are recovering using a special study described below
(electromyography)
e) measure the size of the vocal cords muscles by doing magnetic resonance imaging a
kind of x-ray (MRI) and ultrasound scanning.
These tests are important to measure voice, swallowing and voice box muscles improvement.
After either operation, the participant will be kept overnight at the Royal National Throat
Nose and Ear Hospital. Then, the participant will be seen in clinic 1 month, 3 months and 6
months afterwards so that the doctor can see how the participant is getting on.
Electromyography will be done in the clinic with the patient lying down. It will be carried
out by experienced doctors. One doctor will put tiny needles into the voice-box muscles
being tested through the front part of the neck. The patient will be asked to make sounds to
test how each muscle moves. Typically, this takes about 10 minutes in total. The patient may
experience brief pain or discomfort during insertion of the needles (similar to that when
someone have a blood test at the doctors), but most people find the tests fine. Rarely, there is
temporary mild bleeding or bruising at the needle sites.
In this study, the participant needs to undergo two extra tests that are not done normally for
patients with this problem. The tests are called magnetic resonance imaging (MRI) and
ultrasound scanning which will be carried out at the University College London Hospital. For
MRI, the participant lies down in a dark tube for up to 30 minutes whilst the machine takes
pictures of the voice box. These are like X-rays, but do not have the same risks as X-rays and
give better pictures. However, some people find that lying in the tube is an uncomfortable
experience. It is also noisy, but the participant will be given headphones to make it quieter
and music can be played through these. MRI will be done before surgery and at 6 months
after surgery. For ultrasound scanning, the participant lies down on a couch whilst a doctor
places a small hand-held device that resembles a microphone, attached to the scanner by a
cord. The ultrasound image is immediately visible on a nearby video display screen that looks
much like a computer or television monitor.
Figure 7: A camera connected to a telescope passed through the nose to see
and record the vocal cords movement
What is the potential risk of the study?
Reinnervation and thyroplasty are established operations to treat a paralysed voice box
(larynx) but there is not enough information to tell us which one is better since a study like
this one has not been published yet.
We do not predict any significant disadvantages in taking part in this study. If the participant
is selected for the first operation, it will be done under general anaesthesia instead of local
anaesthesia. An anaesthetist will do an assessment to identify any higher risks than normal of
your having anaesthetic side effects.
Both are safe operations with no significant risk or side effects reported in the literature.
Reinnervation has a delayed effect because the rewired nerve needs at least three months to
regain its function. However the delay in its effect should not be noticeable as we will also
inject some fat to temporarily improve the position of the vocal cord as described.
Possible side effects of the operations are very similar: swelling of the neck, blood clot
accumulation or infection of the wound, and difficulty in breathing may occur. These may
occur with any form of surgery in the neck area, and are not uncommon. The chances of these
happening are the same whichever operation you receive.
Participants need to undergo two extra tests as part of this study which you would not have
received if you were receiving treatment outside a trial. The tests are Magnetic Resonance
Imaging (MRI) and ultrasound scanning which are described above. They will be performed
at the University College London Hospital on the same day. We will repay any costs the
participant have to pay out to attend these scans.
With regards to the MRI and ultrasound scanning, there would be no risk of exposure to
radiation. However some people might experience claustrophobia (a feeling of stuffiness due
to being in a small space) with MRI.
How do I find out more information?
Please contact me by phone: 020 7915 1300 ext 53308 or leave a message and your contact
number to Anne Oliphant (Professor Birchall’s PA) at 02079151308 for me to return your
call. You may email me at [email protected] or send a letter at this address :
Professorial Unit, Royal National Throat Nose and Ear Hospital, 330 Gray’s Inn Road,
London, WC1X 8DA, UK.