What are the possible complications of Gamma Knife radiosurgery?

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What is Gamma Knife Radio surgery (GKSRS)?

• Gamma Knife radio surgery (GKSRS) is a safe,
  effective and non-invasive procedure that uses
  radiation to treat conditions in and around the
  brain. It is sometimes used as a replacement for
  conventional surgery, but at other times it may
  be effective in situations where there is no
  conventional surgical alternative available.

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The radiation treatment is delivered with great
precision to the target tissue within or around
the brain, whilst at the same time minimising any
dose to surrounding healthy tissue. The name
'Gamma Knife' is in some ways misleading - no
knife or cutting implement is actually involved
at any stage. The term 'Gamma Knife' is intended
to convey the idea that this radiation treatment
is in some ways delivered as though it were an
actual knife, because it offers a similar sort of
precision and targeting to that offered by actual
surgery. It uses radiation in much the same way
as a surgeon uses a knife
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Is this treatment right for you?
If you are unsure if Gamma Knife would be a
suitable treatment for your condition or you
would like to find out more please contact us.
Someone will be in touch to tell you more about
the treatment and if it is potentially suitable
for you.
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The multidisciplinary Gamma Knife Surgery team
meet  regularly  to discuss new cases and are
happy to review your scans. There is no cost for
this service. The team includes a neurosurgeon,
radiation oncologists, medical physicist and
nurses. Once your case has been discussed we will
be in contact shortly afterwards to let you know
if Gamma Knife is an option for you or if not we
may be able to advise on other treatments. It can
be a very valuable second opinion free of charge.
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How does Gamma Knife work?
Radiation damages the DNA in the cells of the
tumour or other abnormality being treated, such
that the cells that make up the targeted tissue
can no longer reproduce. Eventually, when these
cells come to the end of their natural life span,
they find that they are unable to reproduce and
replace themselves because the DNA essential to
this process is no longer functioning properly.
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• Some lesions which are very inactive in terms
  of cell function may take up to 2 or 3 years or
  more to respond to treatment -this is typically
  the case for instance with blood vessels, and
  arterio-venous malformations (AVM) which usually
  resolve over this sort of time period.

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Is Gamma Knife Radiosurgery safe?
Yes - in terms of the risk of damage to tissue
around the target area. GKSRS risks can nearly
always be brought down to very low levels - one
of the more common reasons for recommending GKSRS
is that the overall risk compared to open surgery
is frequently much lower. 
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• This is sometimes so much the case that
  the surgical alternative may actually carry a
  higher overall risk than that of the condition
  being treated, thereby rendering it effectively
  inoperable other than by radiosurgery. The
  precise nature and magnitude of any risk will
  vary with the size, nature and position of the
  lesion being treated. You should ask your
  treating doctor to elaborate on the details of
  this with respect to your own individual
  situation - they will be more than happy to give
  you a very full explanation of all that is
  involved. As with any form of surgical or
  radiation treatment, there will always be some
  small risk attached and this can never be reduced
  to zero.

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What are the possible complications of Gamma
Knife radiosurgery?

• Serious complications of GKSRS are really
  very unusual. Minor side effects, which generally
  resolve within a few hours, are sometimes seen
  and do not usually present the patient (or the
  doctor) with a significant problem. It is fair to
  say that the large majority of patients suffer no
  side effects whatsoever, apart perhaps from a
  feeling of being a bit tired and 'washed out' at
  the end of a busy day's treatment! We tend to
  think of complications in terms of those which
  may occur early i.e. soon after treatment, and
  those which can occur at a later stage, some
  weeks or months following GKSRS 

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Early Complications
Common Some local discomfort of the scalp
relating to the pin sites which are used to fix
the frame - resolves within a few hours, almost
certainly by the following morning. Numbness of
the scalp around pin sites may occur which
resolve over a day or two. Headache - again
usually mild, resolving rapidly. Mild
nausea. Delayed complications Uncommon Visual
Loss, Hearing loss, Epileptic seizures, Radiation
effects on surrounding brain tissue. Hair loss
(very localised) adjacent to treated area. These
complications tend to relate only to treatment
for particular conditions. Again your treating
doctor will be able to elaborate on the details
of this with respect to your own individual
situation
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WHAT ARE THE POTENTIAL BENEFITS OF GAMMA KNIFE
RADIOSURGERY OVER CONVENTIONAL SURGICAL
TECHNIQUES?

• Benefits Include
• The risks of infection, haemorrhage and spinal
  fluid leakage are eliminated, as is the scarring
  and potential disfigurement that results from
  conventional neurosurgery.
• The small risk associated with general
  anaesthesia is also eliminated. A mild sedative
  is occasionally used.
• GKSRS is a day procedure except in occasional
  circumstances. 
• GKSRS sometimes can be used in conjunction with
  conventional surgery, usually taking the place of
  the more risky component of the latter. In other
  words, where conventional surgery is absolutely
  required, its risk can be reduced by partially
  substituting GKSRS as a ''boost'' to perform the
  final part of the job.
• An individual who might be a relatively high risk
  candidate for conventional surgery may be a much
  safer candidate for GKSRS.
• Unlike  whole brain radiotherapy GKSRS is
  directed very specifically at the target. This
  spares most of the adjacent normal brain tissue
  from exposure to unnecessary excess radiation.

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• "Fractionation" is not required - unlike
  radiotherapy (such as Linac and SRS which may
  require fractionation) which is often delivered
  in many fractions over several weeks, GKSRS can
  nearly always be delivered as a single treatment
  over the course of less than a day. Multiple
  hospital visits are therefore avoided.
• As a day case treatment GKSRS offers the prospect
  of return to work, driving, and other normal
  social activities within a few days in the vast
  majority of cases. This is frequently as soon as
  the day following treatment.
• Established effectiveness over 40 years of
  experience worldwide, with a very low rate of
  complications

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WILL THE GAMMA KNIFE PROCEDURE HURT?

• The stereotactic frame is fitted under local
  anaesthesia. This involves the administration of
  4 small injections around the circumference of
  the head, in order to numb the sites where the 4
  pins are to be used to secure the frame. The
  experience of these is the same as when visiting
  the dentist for the purpose of having a tooth put
  to sleep for filling. The same local anaesthetic
  drug is used in both instances. Very quickly,
  after a brief stinging sensation, these areas
  will go numb. The frame is then attached. As the
  pins are secured you will feel a strange
  "pressure" sensation which quite soon passes. The
  whole procedure takes about 5 - 10 minutes, and
  after the frame is fitted you will gradually get
  used to the sensation. After a short while you
  will no longer feel this, and you will almost
  forget that the frame is there at all! Frame
  fitting involves a small degree of discomfort,
  but most patients tolerate it remarkably well,
  and tend to comment that it was much preferable
  to the idea of having a major surgical procedure
  performed. At the end of the procedure the frame
  is removed. This only takes a minute or two, and
  is really not at all traumatic. Some patients
  experience headaches after frame removal which
  can be treated with simple pain relief.

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WILL I BE RADIOACTIVE?
No. All radiation stays within the treatment
room. The Gamma rays used in the treatment do not
remain in the body.
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WILL I HAVE SWELLING OR OEDEMA?
In the postoperative period some tumours may
swell a little as a result of being injured by a
dose of radiation. This may show as a slight
increase in apparent size of the tumour as
assessed by MRI or CT scanning at about 6-9
months post treatment. This appearance must not
be misinterpreted as tumour growth. It is
self-limiting, and will soon be followed by
reduction back to original size, or even smaller.
If this temporary swelling (which is actually
indicative that the treatment is starting to
work) causes any symptoms, then a short course of
steroids or other medication is sometimes used to
treat the swelling. 
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WILL I LOSE MY HAIR?
The vast majority of patients have no risk
whatsoever of losing any hair at all.
Furthermore, even in those few cases where hair
loss is a possibility, such hair loss will never
involve the entire scalp - as typically happens
with  whole brain radiotherapy. Only a small
number of patients will have tumours sufficiently
close to the scalp to carry the risk of any hair
loss at all. If a lesion to be treated is very
close to the inside of the skull, it is possible
that enough radiation will be delivered to the
scalp such that a patch of hair the size of a 10
or 20 cent coin may be lost. This hair usually
grows back, though it may be a little lighter in
colour and finer in texture than previously.
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Can Gamma Knife Radiosurgery cause another
tumour?

• Theoretically yes - all forms of radiation
  can in principle cause tumour formation - but
  instances of this actually happening are so rare
  that  there is no direct scientific proof that it
  has been caused by treatment. There are some
  individuals (with rare conditions) who are at
  risk from developing further tumours because of
  their underlying condition, and very occasionally
  (perhaps a dozen times out of tens of thousands
  of patients over several decades), such new
  tumour formation has been reported. Based on
  existing experience, the incidence of radiation
  caused tumours is extremely low, much less than
  the risk of a complication arising from a general
  anaesthetic for example.

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HOW WILL I FEEL FOLLOWING TREATMENT? 

• Most patients feel just as well as they did
  at the beginning of the day. Some tiredness is
  quite common, especially if the treatment has
  occupied most of the day. A little discomfort at
  the pin sites and a mild headache are also quite
  common - this may persist for up to a day or two.
  Mild nausea may also occur during the first 48
  hours following treatment.  Mild anti-nausea and
  headache medication is routinely prescribed for
  patients who may require it. Patients are
  observed for one to two hours post treatment. 

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FOLLOWING TREATMENT WHEN CAN I GO BACK TO WORK?

• As soon as you feel well enough. There is no
  reason why you should not go back to work the
  following day - some patients have even been
  known to return to work later the same day, but
  you should not feel pressured to return to work
  too quickly. It is fair to say that most people
  return to work within less than a week.

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FOLLOWING TREATMENT HOW SOON CAN I TRAVEL (BY
MOTOR VEHICLE, BUS, TRAIN, PLANE)?

• Again, as soon as you feel well enough. There
  is no reason why you could not travel the
  following day, or even some time later on the
  actual day of treatment. Any driving restrictions
  already in place will continue to apply.

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WHAT WILL HAPPEN AFTER TREATMENT?

• You will see a Neurosurgeon and/or Radiation
  Oncologist approximately 4 to 6 weeks post
  treatment, just to check that everything is ok.
  Depending on the condition treated, they will
  arrange for follow-up scans to be performed
  usually at 3 months post treatment. 
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