Botulinum Toxin Injections for the Treatment of Chronic Pain
Botulinum toxin type A injections may be used in selected chronic pain syndromes to reduce pain, particularly when it is associated with excessive muscle activity, prolonged muscle spasm or certain types of localised neuropathic pain. Treatment is planned individually after assessing the cause, location and nature of the pain, as well as previously received therapy. Botulinum toxin can reduce excessive muscle contraction and may also affect certain mechanisms involved in the generation and transmission of pain signals. Botulinum toxin type A has been studied in neuropathic pain of various origins, including pain following nerve injury, trauma or surgery.
Botulinum toxin injections are not a universal treatment for all types of chronic pain; therefore, suitability for the procedure is always determined by a doctor, most commonly a pain specialist (algologist).
What is an algologist?
An algologist is a doctor who specialises in the diagnosis and treatment of pain. They understand the causes and mechanisms of pain and the available treatment methods, helping patients affected by acute or chronic pain. Algologists most commonly treat chronic pain lasting more than three months, although they may also be consulted for acute pain.
What is chronic pain?
Chronic pain is persistent or recurrent pain that may continue even after the initial tissue damage has healed. Its mechanisms can vary considerably: pain may arise from damage or disease of the nervous system, prolonged muscle overload, increased muscle tone, muscle spasms or other health conditions.
For this reason, chronic pain treatment requires assessment not only of where the pain is located but also of the underlying pain mechanism. Burning pain following nerve injury in one patient and persistent painful muscle tension in another may represent entirely different conditions requiring different treatment approaches.
How can botulinum toxin help with chronic pain?
Botulinum toxin blocks the release of acetylcholine at the neuromuscular junction and thereby temporarily reduces excessive activity of a specific muscle. If prolonged muscle contraction or spasm plays a significant role in the development of pain, reducing muscle activity may help to:
reduce excessive muscle tension;
relieve pain associated with muscle spasm;
improve range of motion and everyday functioning;
in selected cases, facilitate rehabilitation and physiotherapy.
The analgesic effects of botulinum toxin that are not solely related to muscle relaxation are also being studied. Research suggests that it may influence the release of neurotransmitters and other substances involved in pain signal transmission. This is one reason why botulinum toxin is being studied and, in selected cases, used in the treatment of localised peripheral neuropathic pain.
In which chronic pain conditions may botulinum toxin injections be considered?
A doctor may consider this treatment for selected patients when chronic pain is associated with a specific pain mechanism and other treatment methods have not provided sufficient benefit.
Neuropathic pain after nerve injury
Neuropathic pain results from a lesion or disease of a nerve or the somatosensory nervous system. It may present as burning, tingling, electric shock-like pain, increased sensitivity or pain caused even by light touch.
Botulinum toxin type A injections have been studied, for example, in localised peripheral neuropathic pain following trauma or surgery, as well as in postherpetic neuralgia, diabetic neuropathy and other neuropathic pain syndromes.
Important: botulinum toxin does not repair a damaged nerve. In such cases, the aim of therapy is to reduce certain pain symptoms.
Painful muscle spasms and increased muscle tone
Botulinum toxin may be considered when pain is associated with persistently increased activity of specific muscles, muscle spasms or abnormal muscle tone. By reducing excessive muscle contraction, it may help relieve tension-related pain and facilitate movement.
Persistent myofascial and muscular pain
In some patients, chronic muscle pain is associated with persistently tense muscles and painful myofascial trigger points. However, botulinum toxin is not automatically suitable for every tense or painful muscle. Therefore, the procedure is assessed individually and is not used as a standard first-line treatment in such cases.
Who may be suitable for botulinum toxin injections?
The procedure may be considered when the likely mechanism of chronic pain has been identified and the doctor has determined that treatment is appropriate for a specific muscle, muscle group or localised painful area.
Assessment of previous treatment is particularly important. Botulinum toxin is often not the first treatment option for chronic pain, but it may be one component of an individual treatment plan when medication, rehabilitation, physiotherapy or other methods have not provided sufficient benefit or are unsuitable.
What happens during the consultation before the procedure?
Before botulinum toxin injections, the doctor assesses the duration, nature and location of the pain, previous illnesses, operations or injuries, medications used and previous pain treatment.
The doctor may assess:
whether the pain is more consistent with neuropathic, muscular or another pain mechanism;
muscle tone, strength and movement function;
painful areas and areas of increased sensitivity;
signs of nerve injury;
possible risks and contraindications associated with the procedure.
Depending on the individual situation, additional investigations or consultation with another specialist may be required before treatment.
How is the botulinum toxin injection procedure performed?
The injection technique depends on the pain syndrome being treated. If the pain is associated with excessive muscle activity, botulinum toxin is injected into the specifically selected muscle or muscles.
For certain types of localised neuropathic pain, the treatment approach and distribution of injections may differ. The doctor individually determines the preparation, dose, number of injections and injection points. Depending on the anatomical area and diagnosis, additional guidance techniques may also be used to ensure accurate placement of the injections.
The duration of the procedure depends on the area being treated and the number of injections required.
When can an effect be expected?
The effect of botulinum toxin is not immediate. Reduction in muscle activity and the analgesic effect usually develop gradually.
The doctor may assess the treatment result after several weeks, taking into account not only pain intensity but also muscle tone, movement function, sleep and the patient’s ability to perform everyday activities.
The strength and duration of the effect are individual and depend on the diagnosis, treated area, preparation used and dose. If the treatment has been effective, the need for and timing of a repeat procedure are determined by the doctor.
What should be observed after the procedure?
After botulinum toxin injections, temporary tenderness, mild pain, redness, swelling or bruising may occur at the injection sites.
Patients should follow the doctor’s individual recommendations. Depending on the condition being treated, botulinum toxin therapy may form part of a broader treatment plan that also includes physiotherapy, rehabilitation, medication or other pain management methods.
Possible side effects and risks
Adverse reactions depend on the injection site, dose and condition being treated. The most common are local reactions such as pain, tenderness, swelling, redness or bruising.
If the preparation is injected into a muscle, temporary weakness of the treated muscle or nearby muscles may also occur.
Product information for botulinum toxin preparations describes rare cases in which the effects may spread beyond the injection site. If pronounced muscle weakness or difficulties with swallowing, speaking or breathing occur after the procedure, urgent medical attention is required.
Contraindications and precautions
The procedure is not performed in cases of known hypersensitivity to the ingredients of the specific botulinum toxin preparation or if there is an infection at the intended injection site.
Particular caution is required in patients with certain neuromuscular disorders, such as myasthenia gravis or Lambert–Eaton syndrome, as well as when taking medications that may affect neuromuscular transmission. Specific contraindications vary depending on the preparation used.
Before the procedure, the doctor should be informed about all medical conditions, medications, previous botulinum toxin injections, as well as pregnancy or breastfeeding.
Important information about the use of botulinum toxin in chronic pain treatment
Botulinum toxin preparations have specific approved medical indications. However, treatment of certain chronic and neuropathic pain syndromes with botulinum toxin may, depending on the diagnosis and the preparation used, be outside its approved indications.
Treatment is therefore provided only after individual medical assessment, with discussion of the potential benefits, alternatives, available evidence and risks.
Botulinum toxin injections are not intended for the treatment of all chronic pain or nonspecific back, neck or muscle pain.
