The surgical management of spasticity.
Neurosurgery is only considered for severe spasticity following the failure of noninvasive management (adequate medical and physical therapy). The patients are carefully selected, based on rigorous multidisciplinary clinical assessment. In this we evaluate the contribution of the spasticity to the disability and any residual voluntary motor function. The goals for each patient are: (a) improvement of function and autonomy; (b) control of pain; and (c) prevention of orthopaedic disorders. To achieve these objectives, the surgical procedure must be selective and reduce the excessive hypertonia without suppressing useful muscle tone and limb functions. The surgical procedures are: (1) Classical neuro-ablative techniques (peripheral neurotomies, dorsal rhizotomies) and their modern modifications using microsurgery and intra-operative neural stimulation (dorsal root entry zone: DREZotomy). These techniques are destructive and irreversible, with the reduced muscle tone reflecting the nerve topography. It is mainly indicated when patients have localized spasticity without useful mobility. (2) Conservative techniques based on a neurophysiological control mechanism. These procedures are totally reversible. The methods involve chronic neurostimulation of the spinal cord or the cerebellum. There are only a few patients for whom this is indicated. Conversely, chronic intrathecal administration of baclofen, using an implantable pump, is well established in the treatment of diffuse spasticity of spinal origin. From reports in the literature, we critically review the respective indications in terms of function, clinical progression and the topographic extent of the spasticity.