Neurosurgical treatment of spasticity: a potential return to the cerebellum

Abstract

Objective: Neurosurgical targeting of the cerebellar dentate nucleus via ablative dentatotomy and stimulation of the dentate nucleus was historically used for effective treatment of spasticity. Yet for decades, neurosurgical treatment of spasticity targeting the cerebellum was bypassed in favor of alternative treatments such as intrathecal baclofen pumps and selective dorsal rhizotomies. Cerebellar neuromodulation has recently reemerged as a promising and effective therapy for spasticity and related movement disorders.

Methods: In this narrative review, the authors contextualize the historical literature of cerebellar neuromodulation, comparing it with modern approaches and exploring future directions with regard to cerebellar neuromodulation for spasticity.

Results: Neurosurgical intervention on the cerebellum dates to the use of dentatotomy in the 1960s, which had progressed to electrical stimulation of the cerebellar cortex and dentate nucleus by the 1980s. By 2024, modern neurosurgical approaches such as tractography-based targeting of the dentate nucleus and transcranial magnetic stimulation of cerebellar cortex have demonstrated promise for treating spasticity.

Conclusions: Cerebellar neuromodulation of the dentate nucleus and cerebellar cortex are promising therapies for severe cases of spasticity. Open areas for exploration in the field include the following: tractography-based targeting, adaptive cerebellar stimulation, and investigations into the network dynamics between the cerebellar cortex, deep cerebellar nuclei, and the subcortical and cortical structures of the cerebrum.

Keywords: DBS; cerebellum; deep brain stimulation; dentate nucleus; neuromodulation; spasticity; transcranial magnetic stimulation.