The occurrence of spasticity is most commonly attributed to the lack of presynaptic inhibition. Perinatal damage to the central nervous system, as it happens in cerebral palsy, leads to pathological reflex response both on segmental and polysegmental levels. It results not only in clinical signs typical for spasticity but also in alterations of brainstem function, such as dysarthria or congenital nystagmus. Selective posterior rhizotomy is a neurosurgical method, routinely used in the treatment of spasticity. The lumbosacral posterior roots are partially cut under perioperative neurophysiological control. The aim of the treatment is the reduction of afferentation for posterior horns resulting in a decrease of pathological reflex responses. Selective posterior rhizotomy consequently decreases lower limbs spasticity. The improvement of upper extremities fine skills, the improvement of speech and cognitive functions has been also observed after selective posterior rhizotomy. The possible pathophysiological explanations of these so-called suprasegmental effects are discussed in the article.

        Key words: spasticity, central nervous system, selective posterior rhizotomy, suprasegmental effects.