Dentate nucleus: a review and implications for dentatotomy.

PURPOSE: The dentate nucleus (DN) is the largest, most lateral, and phylogenetically most recent of the deep cerebellar nuclei. Its pivotal role encompasses the planning, initiation, and modification of voluntary movement but also spans non-motor functions like executive functioning, visuospatial processing, and linguistic abilities. This review aims to offer a comprehensive description of the DN, detailing its embryology, anatomy, physiology, and clinical relevance, alongside an analysis of dentatotomy. METHODS AND RESULTS: We delve into the history, embryology, anatomy, vascular supply, imaging characteristics, and clinical significance of the DN. Furthermore, we thoroughly review the dentatotomy, emphasizing its role in treating spasticity. CONCLUSIONS: Understanding the intricacies of the anatomy, physiology, vasculature, and projections of the DN has taken on increased importance in current neurosurgical practice. Advances in technology have unveiled previously unknown functions of the deep cerebellar nuclei, predominantly related to non-motor domains. Such discoveries are revitalizing older techniques, like dentatotomy, and applying them to newer, more localized targets.

A Case of Dentatotomy for Pain and Spasticity and Systematic Review.

BACKGROUND: Surgical interventions for spasticity aim to improve motor function and pain in cases that are refractory to medical treatment. Ablation of the cerebellar dentate nucleus (dentatotomy) may be a useful alternative. CASE REPORT: A 55-year-old male patient with spasticity, secondary to a traumatic cervical spinal cord injury with quadriparesis, had bilateral lumbar DREZotomy with an improvement that lasted for 6 years. Ten years after the DREZotomy, a progressive increased spasticity manifested as spastic diplegia (Ashworth 4) and spontaneous muscle painful spasms (Penn 4), as well as spasticity in the upper extremities, predominantly on the right side (Ashworth 3). A right radio frequency dentatotomy was performed with intraoperative electrophysiological monitoring. Spasticity scales were applied at the following times: preoperative and at 1 and 8 months after surgery. During the first month, the patient presented a clear decrease in spasticity ipsilateral to the side of lesioning (Ashworth 1) and of painful spasms in the lower extremities (Penn 1). After 8 months, spasticity ipsilateral to the injury decreased even more to Ashworth (0), but a progressive increase in muscle spasms of lower extremities was observed (Penn 2). CONCLUSION: Stereotactic dentatotomy may be an effective surgical alternative for management of spasticity associated with painful spasms in selected patients.

Evaluating cerebellar dentatotomy for the treatment of spasticity with or without dystonia.

Spasticity represents a common and very often incapacitating neurologic condition, for which a limited number of treatment options are available. Stereotactic ablation of the dentate cerebellar nuclei (dentatotomy) was widely used in the past with variable results. In the present study, we reviewed 12 consecutive cases operated on at the Midland Centre for Neurosurgery and Neurology at Birmingham University (Smetwick, UK) in the 1980s. The following clinical aspects were analyzed: severity of spasticity, occurrence of abnormal movements (dystonia/athetosis), language fluency, gait, and overall clinical condition. Follow-up ranged from 0.5 to 94 (mean: 31.6) months. Immediate improvement was noted in 10 patients, and five of them had sustained this improvement at the time of the last assessment. A more pronounced improvement was observed for gait, relative to speech and abnormal movements. No significant morbidity related to the procedure was observed. We conclude that dentatotomy is a safe procedure that should still be considered in specific cases. Here, we review the cases reported in the literature, and present a mechanistic hypothesis about how dentatotomy influences motor tonus, in light of the current knowledge about cerebellar physiology. We believe that this issue is critical for the development of alternative surgical approaches targeting the cerebellum, such as chronic electric stimulation.

Long-Term Outcome of Dentatotomy in a Dystonic Patient

Dystonia is characterized by sustained or intermittent muscle contractions leading to abnormal movements and impairment in daily activities. Stereotactic dentatotomy has been a treatment option in cases of spasticity or dystonia, especially in patients with cerebral palsy, but the long-term effect of dentatotomy in dystonia is still unknown. Here we describe a dystonic patient who underwent dentatotomy for symptomatic treatment of refractory dystonia and whose 20-year follow-up showed improvement in symptoms.

A distonia é caracterizada por contrações musculares intermitentes ou sustentadas que levam a movimentos anormais e ao comprometimento das atividades cotidianas. A dentatotomia estereotáxica tem sido uma opção de tratamento nos casos de espasticidade ou distonia, especialmente em pacientes com paralisia cerebral, mas o efeito a longo prazo da dentatotomia na distonia ainda é desconhecido. Descrevemos aqui um paciente submetido a dentatotomia para tratamento sintomático de distonia refratária e cujo acompanhamento por 20 anos demonstrou melhora nos sintomas.