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::''This article deals with Selective Dorsal Rhizotomy (SDR) rather than the rhizotomy procedures for pain relief; for those procedures, which have begun to take the name "rhizotomy" in certain instances, see facet rhizotomy and similar.'' A rhizotomy ( ) is a term chiefly referring to a neurosurgical procedure that selectively destroys problematic nerve roots in the spinal cord, most often to relieve the symptoms of neuromuscular conditions such as spastic diplegia and other forms of spastic cerebral palsy.〔("Does sacral posterior rhizotomy suppress autonomic hyper-reflexia in patients with spinal cord injury?" ), USUJ 2009. Retrieved 2010-04-13〕 The selective dorsal rhizotomy (SDR) for spastic cerebral palsy has been the main use of rhizotomy for neurosurgeons specialising in spastic CP since the 1980s; in this surgery, the spasticity-causing nerves are isolated and then targeted and destroyed. The sensory nerve roots, where spasticity is located, are first separated from the motor ones, and the nerve fibres to be cut are then identified via electromyographic stimulation. The ones producing spasticity are then selectively lesioned with tiny electrical pulses. In spasticity, rhizotomy precisely targets and destroys the damaged nerves that don’t receive gamma amino butyric acid, which is the core problem for people with spastic cerebral palsy. These over-firing, non-GABA-absorbing nerves generate unusual electrical activity during the EMG testing phase in SDR and are thus considered to be the source of the patient's hypertonia; they are eliminated with the electrical pulses once identified, while the remaining nerves and nerve routes carrying the correct messages remain fully intact and untouched. This means that the spasticity is permanently dissolved, and that this is done without affecting nervous system sensitivity or function in other areas, because the only nerves destroyed are the over-firing ones responsible for the muscle tightness. The terms ''rhizotomy'' and ''neurotomy'' are also increasingly becoming interchangeable in the treatment of chronic back pain from degenerative disc disease. This is a procedure called a facet rhizotomy〔http://www.spineuniverse.com/treatments/pain-management/facet-rhizotomy>〕 and is not a surgical procedure but is instead done on an outpatient basis using a simple probe to apply radiofrequency waves to the impinged pain-causing nerve root lying between the facet joint and the vertebral body. Such radio frequency nerve lesioning results in five to eight or more months of pain relief before the nerve regenerates and another round of the procedure needs to be performed. A facet rhizotomy is just one of many different forms of radiofrequency ablation, and its use of the "rhizotomy" name should not be confused with the SDR procedure. ==Background== Dorsal rhizotomy or selective dorsal rhizotomy (SDR), less often referred to as selective posterior rhizotomy (SPR), is the most widely used form of rhizotomy, and is today a primary treatment for spastic diplegia, said to be best done in the youngest years before bone/joint deformities from the pull of spasticity take place, but it can be performed safely and effectively on adults as well. An incision is made in the lower back just above the buttocks and the nerves accessed and dealt with are in that area of the spinal column. SDR is a permanent procedure that addresses the spasticity at its neuromuscular root: i.e., in the central nervous system that contains the misfiring nerves that cause the spasticity of those certain muscles in the first place. After a rhizotomy, assuming no complications, the person's spasticity is usually completely eliminated, revealing the "real" strength (or lack thereof) of the muscles underneath. SDR's result is fundamentally unlike orthopaedic surgical procedures, where any release in spasticity is essentially temporary. Because the muscles may have been depending on the spasticity to function, there is almost always extreme weakness after a rhizotomy, and the patient will have to work very hard to strengthen the weak muscles with intensive physical therapy, and to learn habits of movement and daily tasks in a body without the spasticity. Rhizotomy is usually performed on the pediatric spastic cerebral palsy population between the ages of 2 and 6, since this is the age range where orthopedic deformities from spasticity have not yet occurred, or are minimal. It is also variously claimed by clinicians that another advantage to doing the surgery so young is that it is inherently easier for these extremely young children to restrengthen their muscles and to re-learn how to walk, often having the effect that later in life, they do not even remember the period of time when they lived with the spasticity at all. However, recent cases of successful SDR procedures among those with spastic diplegia across all major age ranges (years 3-40 and even above) has finally proven its universal effectiveness and safety regardless of the age of the spastic diplegic patient. A counter-argument against the prevailing view concerning the younger years is that it may actually be quicker and easier to restrengthen an older patient's musculature and regaining of walking may happen faster with an older patient due to the fact that the patient is fully matured and very aware of what is going on, and so may work harder and with more focus than might a young child. These two schools of thought have equally objectively-valid bases for their formation and thus are each defended quite intensely by their respective proponents. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「rhizotomy」の詳細全文を読む スポンサード リンク
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