**Abstract**

Spasticity is one of the most important and residual signs after pyramidal and para-pyramidal catastrophic lesions after diverse neurological insults, including stroke, brain and spine trauma and post-radiation; infection and immunological diseases affecting nervous system, between others. Spasticity is normally a compensatory motor mechanism that could ameliorate the patients´ disability. Nevertheless, disastrous spasticity is described when the extremities force is diminished in the affected limbs, or when is impossible to wake o to take objects, maximum when hand or foot deformity is exposed. The objective of this chapter is centered in the neurosurgical treatment of spasticity, including brain lesions with specific targets and the spine with its different modalities. This review shows not only the basic aspects in these techniques, but also the option of infusion pumps and deep brain stimulation. To close, a proposal is stablished to determinate the possible path to treat the spasticity in the future.

**Keywords:** spasticity, neuroablation, neuromodulation, lesioning neurosurgery, motor disorders

### **1. Introduction**

Spasticity is a motor disorder characterized by muscular hypertonia with resistance to passive movement, in a context of hyperexcitability of the stretch reflex. This disorder is a component of the upper motor neuron syndrome, an alteration where the inhibitory influence of supraspinal structures is lost. Spasticity is an important clinical problem frequently found in neurological patients. This condition is estimated to occur in 17–39% of patients with stroke [1], 37–78% of patients with multiple sclerosis [2], 65–78% of patients with spinal cord injury [3], and 90% of patients with cerebral palsy [4]. Spasticity could be very disabling for patients and its management requires several specialists and different therapeutic options.

If acceptable control of spasticity is not achieved with pharmacological treatment, physical therapy and rehabilitation, surgical procedures are the next treatment option. The goal of surgery in these patients is to decrease the excess muscle tone and rebalance agonist and antagonist muscle groups to improve function

and limit deformities. To promote a better restoration of function in patients with spasticity, it is important to know the functional alterations of this disorder. Furthermore, in order to measure the effects on the pathology after some treatment, it is necessary to use classifications and scales. In the following sections, the first topic to be addressed is the neurophysiological alterations of spasticity and then it will be mentioned the scales with which the degree of affection is classified. Later, it is going to be described the neurosurgical procedures, both ablative and neuromodulatory, available to compensate for the physiological alterations of this disorder.
