Botulinum therapy of movement disorders is today a separate, well-studied branch of neurology. Numerous studies and fundamental monographs have been devoted to the scientific and clinical aspects of botulinum toxin. It would not be an exaggeration to say that it was the beginning of the use of botulinum toxin that gave rise to interest in studying the pathophysiology of focal dystonias and other dyskinesias.
Orlova Olga Ratmirovna - neurologist, Doctor of Medical Sciences, Professor of the Department of Nervous Diseases of the First Moscow State Medical University. THEM. Sechenov and the Department of Plastic and Reconstructive Surgery, Cosmetology and Cellular Technologies of the Russian National Research Medical University, President of the Interregional Public Organization of Botulinum Therapy Specialists (MOOSBT)
Focal dystonias
The term "dystonia" is used to describe a neurological syndrome characterized by prolonged muscle contractions, often resulting in repetitive deforming movements and persistent abnormal postures in the affected areas of the body. The history of studying the clinic, morphology, etiology and pathophysiology of dystonia has more than a hundred years, from the moment when in 1887 H. Wood described facial and oromandibular dystonia in a textbook on nervous diseases. Since 1983, high doses of anticholinergics have been used to treat dystonia, in 1985 A. Scott first used local injections of botulinum toxin to treat blepharospasm. In 1989, Ozelius located the gene for autosomal dominant dystonia on chromosome 9q32-34.
The most common forms of focal dystonia are cranial dystonia (CD), which includes syndromes of blepharospasm, oromandibular dystonia, laryngeal and pharyngeal dystonia, cervical dystonia (CD), writer's spasm (PS), and other "professional" dystonias (in typists, telegraph operators, musicians, etc.). A rare form is focal foot dystonia.
Focal dystonia affects people of working age, a high degree of social maladaptation and disability of patients due to the formation of a pronounced functional defect in them (functional "blindness" with blepharospasm, impaired speech, chewing and swallowing – with oromandibular and pharyngeal dystonia, voice formation – with laryngeal dystonia, holding the head in a straight position – with cervical dystonia, writing disorders – with writing spasm, etc.).
The vast majority of patients with both idiopathic and symptomatic dystonia require therapy that is nonspecific and addresses the symptoms rather than the causes of the disease, which are still undiscovered.
Non-specific therapies can be divided into three types:
1) systemic and local pharmacotherapy;
2) surgical interventions;
3) physical and behavioral modification methods, feedback and other types of afferent and relaxation influences.
For the treatment of dystonia, various groups of drugs were used that affect the metabolism of dopamine, catecholamines, acetylcholine, serotonin, GABA and other biologically active substances. Practice shows that their average therapeutic efficacy does not exceed 20-30%, and their effect is, as a rule, temporary. The best results in some cases have been achieved with the use of anticholinergics (dexethimide, trihexyphenidyl, triperiden, biperiden), as well as a combination of GABA-ergic drugs clonazepam and baclofen. Antipsychotics, dopamine agonists and other drugs play a significantly smaller role in the treatment of dystonia, especially in comparison with botulinum toxin therapy.
Surgical treatments include stereotactic operations (thalamotomy, pallidotomy), high-frequency stimulation of the nuclei of the thalamus and globus pallidus, as well as peripheral operations (cervical radicotomy, decompression of the accessory nerve, selective denervation and rhizotomy, myoectomy). However, the therapeutic effect of these effects is often temporary, and is also associated with a high risk of functional disorders, especially after bilateral brain surgery (paresis, dysarthria, dysphagia, mental disorders). Usually, surgical treatment is used in cases of persistent therapeutic resistance to systemic and local pharmacotherapy.
Methods of local denervation pharmacotherapy include intramuscular administration of botulinum toxin preparations, alcohol– novocaine mixture and phenol. Phenol injections have side effects in the form of persistent dysesthesias, therefore they are not widely used, despite the low cost. Alcohol blockades are painful and their effect is short-lived.
The most common treatment for focal dystonia in the world is repeated local injections of botulinum toxin.
It is preferable that the treatment of focal dystonia with botulinum toxin be performed by a neurologist with specialization and experience and interest in the field of movement disorders, therefore the organization of outpatient clinical centers for movement disorders and botulinum therapy is encouraged. Dosages of BTA preparations and activity units of Dysport and Botox (measured in mouse units of action) are individual, but in clinical practice the most optimal ratio is Dysport : Botox = 3–4 U: 1 U. The optimal dose for local intramuscular injection in the treatment of blepharospasm is 120 & ndash; 200 IU of Dysport per 1 procedure, in the treatment of spastic torticollis – 500–800 units of Dysport (for 1 procedure). Injections are repeated 2-3 times a year, but there are cases when
The initial recommended dose in the treatment of cervical dystonia is 500 IU of Dysport. The drug is diluted in 1 ml of solution of sodium chloride. Injections are given intramuscularly. The total dose is divided accordingly according to the condition of the affected muscles and the type of torticollis.Hemifacial spasm (HFS)
This is peripheral myoclonic hyperkinesis, manifested by short-term involuntary contractions of the muscles of one half of the face innervated by the facial nerve (all facial muscles, m. platyzma and m.stapedius in the middle ear). The most common cause of HPS – irritation or compression of the facial nerve root at the site of its exit from the pons of Varolii by an abnormally located artery at the base of the brain. In addition, other processes in the region of the cerebellar pontine angle (tumor) can manifest as symptoms of HPS, so neuroimaging (MRI of the head) should be performed in each patient to exclude a volumetric process. HPS occurs in adulthood, more often in women, and in 70–90% – on the left side of the face. Surgical treatment can give a lasting effect – microvascular decompression,
Botulinum toxin injections are the treatment of choice for most HPS patients.
Injection tactics – the same as with blepharospasm, but only on one side. Dose of Dysport – 60–100 IU for 1 procedure.
Treatment of spasticity and cerebral palsy
This is a treatment – always staged, complex, it is preferable that it be carried out in specialized centers, where botulinum toxin plays a key role in a number of other rehabilitation methods. The objectives of treating spasticity with botulinum toxin in adults should be realistic: improving functionality, treating pain and muscle spasms, facilitating physiotherapy sessions, facilitating care for an immobilized patient, eliminating a cosmetic defect, improving functionality in the treatment of urinary disorders (sphincter spasm); as a result – early activation of the patient.
The functional results of using BTA in the treatment of spasticity are obvious: an increase in walking speed, step length, an increase in the functionality of the hand, an improvement in wheelchair control, facilitation of care for immobilized patients, prevention of musculoskeletal complications (contractures, subluxations, muscle spasms, etc.) and cosmetic defects.
The goals of treating spasticity in cerebral palsy can be divided into short-term and long-term. Short term – improve limb function, reduce pain and discomfort, improve self-care. Long-term – prevent changes in muscle tissue, lengthen muscle fibers, improve limb growth, prevent the development of dynamic and fixed contractures, prevent changes in tendons, deformities and dystopias of the joints and skeleton in a later period, avoid or delay surgery. The use of botulinum toxin in cerebral palsy is indicated with relative preservation of muscle function, in cases of dynamic (not fixed) contracture, with the possibility of using synergist and antagonist muscle functions in rehabilitation, with preservation of motivational behavior.
Botulinum toxin for pain syndromes
Migraine – one of the most famous and widespread neurological diseases, occurs in the adult population with an average frequency of 12% (6% in men and 18% in women) and 4% – in childhood. Recent studies have shown the effectiveness of botulinum toxin preparations in a variety of pain syndromes, including neuropathic pain, back pain, whiplash pain, and migraine and other types of chronic headaches.
While migraine is not a life-threatening disease, it significantly reduces the quality of life of patients. The World Health Organization classifies migraine as one of the most debilitating chronic diseases. The treatment of migraine attacks has become highly effective with the introduction of 5-HT1B/1D-agonists known as triptans into widespread clinical practice.
Prophylactic (preventive) treatment of migraine, on the contrary, is treated with caution, often neglecting it. It has been shown that only 3-5% of migraine patients who need preventive treatment actually receive such help. The use of botulinum toxin type A (BTA) is a new approach in the prevention of headaches, given the good tolerability of treatment, safety, lack of systemic side effects and long duration of action – characteristics that are very advantageous for continued use in clinical practice.
BTA was first noted for its effectiveness in headaches by plastic surgeon William Binder, when many of his patients who received botulinum toxin injections to correct facial wrinkles in the brow region noted a reduction in the frequency and severity of headaches. Following these initial observations, a multicentre, open-label study of BTA in patients with migraine was conducted, sparking a surge of interest in this area.
For migraine, botulinum toxin type A preparations are usually injected into the glabella, temporal, frontal, and sometimes occipital regions. Several techniques are used: "fixed points"; "follow the pain", when the choice of points for injection depends on the localization of pain or muscle tension; or a combination of them. Before injections, the "anatomical" localization of pain is clarified and the pericranial muscles, muscles of the posterolateral region of the neck and shoulder girdle are palpated to identify zones of muscle tension. The choice of the BTA injection technique largely depends on the patient's complaints and medical examination data. The "fixed points" technique is more often used for migraine , and the "following the pain" technique for tension headaches;
Several theories have been proposed for the antinociceptive effects of botulinum toxin.
1. By attenuating prolonged muscle contraction, botulinum toxin can reduce the release of various substances that lead to sensitization of muscle nociceptors.
2. By affecting the activity of muscle spindles, botulinum toxin can indirectly (indirectly) reduce muscle pain associated with excessive muscle contraction. Since muscle spindle afferents have important supraspinal projections, changes in their activity after injections of botulinum toxin can change the activity of sensory systems at the CNS level.3. Botulinum toxin can suppress neurogenic inflammation, the role of which is discussed in the pathogenesis of migraine and other pain syndromes.
4. Botulinum toxin can interfere with the release of not only acetylcholine, but also other neurotransmitters. There is evidence that BTA inhibits the release of substance P in vitro. In vivo, the effect of BTA on the pain behavior of rats was shown, which is associated with a decrease in the release of glutamate.
Clinical and preclinical studies indicate that BTA may affect many stages of the pathophysiological cascade in headaches, although it is not clear which stage is considered the most important.
The use of BTA for other primary headaches such as tension headaches, cluster headaches, chronic paroxysmal hemicrania also requires further research. For practitioners who regularly deal with headaches, BTA preparations are becoming a valuable drug in the treatment of patients with severe migraine attacks and chronic migraine.
Botulinum toxin is actively and successfully used in the treatment of myofascial pain syndromes (shoulder & ndash; scapular periarthropathy syndrome, upper chest aperture, back pain, tennis elbow, facial myofascial pain syndrome). Neurologists have made significant progress in this direction.
The article is printed in abbreviated form.
According to rmj.ru
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