What is botulinum toxin and how does the treatment work? Botulinum toxin (BTX) is a neurophagic protein produced by the anaerobic bacterium Clostridium botulinum G+. Botulinum toxin was discovered as early as the late 19th century. In 1946, Schantz EJ purified botulinum toxin crystals, and in 1973, Dr. Scott first demonstrated in animal experiments that BTX-A has the effect of paralyzing the extraocular muscles. 1979, Scott first injected botulinum toxin into the over-contracted eye muscles of volunteers under the monitoring of ocular electromyography and successfully corrected strabismus. pioneering studies confirmed that botulinum toxin type A can be safely and effectively used to treat muscle disorders. In addition to its use for strabismus, Scott et al. began studies on the treatment of dystonia such as blepharospasm, and later expanded to other facial dystonia, spastic squint, treatment of limb dystonia (e.g., spinal cord injury, limb muscle spasm after stroke, spasticity in children with cerebral palsy), neurogenic bladder and rectal sphincter spasm due to spinal cord injury, and the treatment of axillary odor by inhibiting the secretion of sweat glands It is also used to treat axillary odor by inhibiting the secretion of sweat glands. It is currently one of the preferred methods in the field of rehabilitation medicine to relieve muscle spasm caused by stroke, cerebral palsy, traumatic brain injury, spinal cord injury and other upper motor neuron injuries, and can effectively improve patients’ motor function and self-care ability. BTX-A acts selectively on peripheral cholinergic nerve endings and is strongest at the neuromuscular junction (i.e., synapses). Botulinum toxin acts on the presynaptic membrane of the motor nerve endplates, blocking the release of acetylcholine into the synaptic gap; the nerve endplates gradually degenerate and die, resulting in the inability of the affected nerve to stimulate the contraction of the innervated muscle, resulting in a temporary reduction in muscle strength or paralysis. The effective action of botulinum toxin usually arrives within 3-14 days, and the blocking effect can last for several 3-6 months. When the motor nerve endings are paraplegic, new motor end plates are formed and replace the dead end plates, the muscle regains innervation and gradually regains function or reappears in a state of muscle spasm again. Botulinum toxin type A (BOTOX) is one effective treatment for spasticity in young children with cerebral palsy. Toe walking in children with cerebral palsy is caused early on by spasticity of the calf muscles, so it is impossible for the child to follow his or her foot to the ground while walking. Botox blocks the signaling between the nerve and its target muscle and reduces excessive stiffness of the spastic muscle. BOTOX acts locally on the muscle to overcome stiffness, allowing more normal growth and effective rehabilitation of the developing muscle, increasing the length of the spastic muscle, reducing the risk of contracture, reducing the need for surgery, and increasing the chance of normal muscle growth and development. Although, the spastic state of the muscle may reappear 3 to 6 months after the injection, Botox injection is not simply to reduce muscle tone, but to regain and improve, after the injection, the function of the muscle group lost due to dystonia, so regular rehabilitation after the injection is very important, even though the spastic state may reappear, it will be reduced, and the child’s motor ability and muscle strength will be greatly improved. Is botulinum toxin safe? Botulinum toxin type A is a toxin that was first discovered when people mistakenly ate spoiled sausages and died due to ingesting large amounts of botulinum toxin. The current projected use limit for botulinum toxin type A is an LD50 of approximately 40 units/kg, or 2,400 units for a 60 kg person, although the amount currently in clinical use is very small and therefore safe. Botulinum toxin type A treatment is safe and no teratogenicity has been reported, but after all, experience is limited and therefore BTX-A is not recommended for pregnant or breastfeeding women. botulinum toxin should not be used in patients with neuromuscular diseases, especially those affecting the neuromuscular junction, such as myasthenia gravis. In contrast, allergy and hypersensitivity to the drug, infections or skin breakdown at the injection site, patients with fever and acute infectious diseases, and patients with serious organ diseases should be contraindicated for Botox injections. Because aminoglycoside antibiotics (such as gentamicin) can enhance the effect of botulinum toxin, the use of these antibiotics should be prohibited during the use of botulinum toxin. In addition, cholinesterase antagonists, succinylcholine, arrow toxin-like depolarization antagonists, sulfatase, quinidine, calcium channel blockers, lincomycin, polymyxin, etc. are prohibited during botulinum toxin. Botulinum toxin injections generally have no effect at the time, and it takes 3 d to 2 weeks for the drug to take effect, so it is not possible to judge prematurely whether the treatment dose is insufficient. Also, since repeated injections can cause immune resistance, additional injections should not be given within 3 months after the injection to avoid affecting the effect of repeated injections. It is generally believed that repeated injections can be given after 3 months when the therapeutic effect is weakened, at which time repeated injections of BTXA can generally still have a therapeutic effect, and repeated injections do not cause accumulation of toxicity. Use ice packs locally after injection; gently compress locally after injection instead of massaging, and do not massage locally within 2-3 hours after injection; active muscle contraction activity and electrical stimulation after injection are conducive to drug internalization and improve drug action. Therefore, patients should be encouraged to strengthen functional exercises after injection without resting and braking. Evidence from 20 RCTs and 2 meta-analyses illustrates that treatment with botulinum toxin results in a significant decrease in muscle tone and improvement in passive function (reduced impairment and increased ability to participate in activities). There is growing evidence that reducing spasticity improves active function, i.e., reduces activity limitation. To date, although there are no randomized clinical trials, functional improvement has been reported by reducing knee stiffness gait. Reducing muscle tone increases the likelihood of functional training. Therefore, the use of botulinum toxin is beneficial in improving function. Repeated use of botulinum toxin can significantly improve mobility, improve the ability to use the affected limb, reduce the burden on caregivers, and is an effective way to relieve muscle spasm. Side effects of botulinum toxin Botox injection treatment may have certain complications and side effects, which often occur 3 to 5 days after treatment, but of course these side effects will be reduced with time until they disappear, and generally gradually subside in 2 to 4 weeks. The common ones are skin allergy and rash, numbness and pain at the injection site, bleeding and hematoma at the injection site, “flu-like” symptoms, weakness of the adjacent muscles, and in rare cases, anaphylaxis. Most children with cerebral palsy tolerate botulinum toxin injections very well. However, some children may experience mild and temporary side effects in the first few weeks after injection, such as pain at the injection site; the most common side effect is a feeling of tenderness; few children experience leg cramps and fever; temporary urinary incontinence and constipation have also occurred in children after thigh injection, but rarely. The child’s response to re-injection treatment will diminish. How is BOTOX administered? Before administering Botox injections to a child with spastic cerebral palsy, the child should be examined in detail to ensure that the right child is treated and to develop a treatment plan. Treating Children with Botox A specific plan is developed for each child so that the expected outcome is very easy to understand. Botox is not recommended for use in children under 2 years of age. Botox injections are used in very small doses, and each muscle will be injected at multiple points as needed to relax the muscle being treated. Sedation may be given to young, anxious or uncooperative children. Importance of physical therapy after Botox injection treatment Physical therapy after Botox injection is very important, and only intervention of comprehensive and effective rehabilitation can ensure the results and prolong and maximize the effects of Botox treatment. Parents will play a very important role in the daily rehabilitation of their child. In many children with spastic cerebral palsy, Botox injections combined with physical therapy can completely eliminate the need for surgery. Depending on the degree of contracture and deformity of the child after injection therapy, the use of continuous cast immobilization or an appropriate brace to help distract the muscles will be an option to help maintain the beneficial effects of the injections and improve motor control, especially of the knee and ankle joints. Gait training is also an important treatment item in rehabilitation. What can we expect? Botulinum toxin does not work miracles, so it is not a complete cure for cerebral palsy. Botox injections are effective in creating the conditions for rehabilitation. The effectiveness of the injections depends on the degree of spasticity, the age of the child, the method of physical therapy after the injection and the duration of adherence. In children with lower limb spasticity, the change from toe walking to heel-toe walking is usually 2 weeks after injection, and the gait can be improved to maximum effect after 6 weeks, and can effectively train and improve the child’s balance function and make walking easier. Botulinum toxin is most effective when used in the early stages of spasticity, and sometimes, it can provide long-term, permanent results. While many children will eventually require orthopedic surgery, Botox injections, which can delay surgery until the child is 10 years old or older, are received as a simple surgical procedure and allow the child to undergo only one surgical procedure for life.