Botulinum Toxin (Botox)

One treatment for spastic muscles is to paralyse them with Botox injections.  When Charlie was referred for Botox people thought it was a cosmetic surgery- ‘how young do you want him to look?’, ‘he’ll be the youngest looking 2 year old ever…!’ were just a number of comments.

Obviously, Botox gets a lot of coverage in the press as a cosmetic surgery for the rich and famous; a treatment to remove wrinkles by paralysing muscles to stop them creasing up the forehead or ‘crows feet’ around the eyes.  However, it is used in people with overactive sweat glands but also as a treatment for spastic muscles -to paralyse the ‘too strong’ muscle with injections to enable another muscle to become relatively stronger.

Botox is actually a poison- it is the same bacterium that causes botulism, Clostridium, and was originally seen in those handling bad meat, hence it was also known as ‘sausage poison’.

toe pointingMuscles act in pairs- an agonist and its antagonistic mate, like the bicep and the tricep.  As one contracts the other is stretched and vice versa.  With spasticity one muscle (usually the extensor) is sent too much information telling it to pull.  Usually a still limb is sent an equal amount of stimulus to both of a pair, telling it to pull equally to remain stationary.  An unmoving muscle is still sent info- this shows us why we need muscle tone- both muscles being slightly active until one is instructed to work more, moving the joint/limb- this also acts as a ‘braking mechanism’.  When we have low muscle tone insufficient info is sent to the muscles meaning they don’t work enough- this can cause a joint to be weak, lax or subject to hypermobility. With high muscle tone, or spasticity, one of the pair is sent too much info making it contract out of balance (eg pointing the toes or twisting the hand into a tight grip).

knee-final2This principle of an active balance, or equilibrium, is where Botox can help.  As we are unable to easily excite a weakened muscle artificially it is much easier to try to weaken a stronger one- Botox injections paralyse muscle fibres temporarily.  This weakening of a spastic muscle can try to allow a muscle to stretch more, simply as it is no longer in a state of constant contracture.  It also tips the balance of strength toward the weaker muscle enabling it to perform its function more appropriately and allowing it to strengthen.

Botox was injected into Charlie’s legs- specifically his hamstrings, adductors (inside thigh) and his calf to weaken them to allow greater movement in them.  It allowed these regularly tight muscles to be weakened and it helped stop Charlie point his toes or cross his legs (scissoring) unintentionally.  Its effect is described in The Story So Far… Part 9 (Orthopaedics).

Although painful to inject the Botox is a helpful way of making highly spastic muscles more comfortable.  It has a time-limited effect as it wears off, typically 6 months but that time allows rigorous physio and stretching exercises to be performed.  It can be reapplied but it does suffer from ‘diminishing returns’- each application is less effective than the previous so its usefulness has to be carefully assessed.

All in all a very  helpful temporary respite for stiff, aching muscles but certainly not a cure…

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