Cerebellar Mutism After Posterior Fossa Surgery —Two Case Reports—

Background: In brain tumor surgery, injury to cerebellar connectivity pathways can induce a neurodegenerative disease called hypertrophic olivary degeneration (HOD), along with a disabling clinical syndrome. In children, cerebellar mutism syndrome (CMS) is another consequence of damage to cerebello–thalamo–cortical networks. The goal of this study was to compare paravermal trans-cerebellar to other more midline or lateral operative approaches in their risk of causing HOD on MR-imaging and CMS. Methods: We scanned our neurosurgical database for patients with surgical removal of pilocytic astrocytoma, ependymoma and medulloblastoma in the posterior fossa. Fifty patients with a mean age of 22.7 (±16.9) years were identified and analyzed. Results: HOD occurred in n = 10/50 (20%) patients within four months (median), always associated with contralateral dentate nucleus (DN)-lesions (p < 0.001). Patients with paravermal trans-cerebellar approach significantly more often developed HOD (7/11; 63.6%) when compared to other approaches (3/39; 7.7%; p < 0.001). Injury to the DN occurred more frequently after a paravermal approach (8/11 vs. 13/39 patients; p < 0.05). CMS was described for n = 12/50 patients (24%). Data indicated no correlation of radiological HOD and CMS development. Conclusions: A paravermal trans-cerebellar approach more likely causes HOD due to DN-injury when compared to more midline or lateral approaches. HOD is a radiological indicator for surgical disruption of cerebellar pathways involving the DN. Neurosurgeons should consider trajectories and approaches in the planning of posterior fossa surgery that spare the DN, whenever feasible.

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Feasibility of cerebello-cortical stimulation for intraoperative neurophysiological monitoring of cerebellar mutism

Child s Nervous System ◽

10.1007/s00381-021-05126-7 ◽

2021 ◽

Author(s):

Davide Giampiccolo ◽

Federica Basaldella ◽

Andrea Badari ◽

Giovanna Maddalena Squintani ◽

Luigi Cattaneo ◽

...

Keyword(s):

Motor Cortex ◽

Test Stimulus ◽

Posterior Fossa ◽

Motor Evoked Potentials ◽

Significant Inhibition ◽

Neurophysiological Monitoring ◽

Posterior Fossa Surgery ◽

Cerebellar Mutism ◽

Motor Cortex Excitability ◽

Electrical Conditioning

Abstract Background Cerebellar mutism can occur in a third of children undergoing cerebellar resections. Recent evidence proposes it may arise from uni- or bilateral damage of cerebellar efferents to the cortex along the cerebello-dento-thalamo-cortical pathway. At present, no neurophysiological procedure is available to monitor this pathway intraoperatively. Here, we specifically aimed at filling this gap. Methods We assessed 10 patients undergoing posterior fossa surgery using a conditioning-test stimulus paradigm. Electrical conditioning stimuli (cStim) were delivered to the exposed cerebellar cortex at interstimulus intervals (ISIs) of 8–24 ms prior to transcranial electric stimulation of the motor cortex, which served as test stimulus (tStim). The variation of motor-evoked potentials (MEP) to cStim + tStim compared with tStim alone was taken as a measure of cerebello-cortical connectivity. Results cStim alone did not produce any MEP. cStim preceding tStim produced a significant inhibition at 8 ms (p < 0.0001) compared with other ISIs when applied to the lobules IV-V-VI in the anterior cerebellum and the lobule VIIB in the posterior cerebellum. Mixed effects of decrease and increase in MEP amplitude were observed in these areas for longer ISIs. Conclusions The inhibition exerted by cStim at 8 ms on the motor cortex excitability is likely to be the product of activity along the cerebello-dento-thalamo-cortical pathway. We show that monitoring efferent cerebellar pathways to the motor cortex is feasible in intraoperative settings. This study has promising implications for pediatric posterior fossa surgery with the aim to preserve the cerebello-cortical pathways and thus prevent cerebellar mutism.

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Cerebellar mutism in adults after posterior fossa surgery: a report of 2 cases

Surgical Neurology ◽

10.1016/j.surneu.2004.06.015 ◽

2005 ◽

Vol 63 (5) ◽

pp. 476-479 ◽

Cited By ~ 22

Author(s):

Jonathan H. Sherman ◽

Jason P. Sheehan ◽

W. Jeffrey Elias ◽

John A. Jane

Keyword(s):

Posterior Fossa ◽

Posterior Fossa Surgery ◽

Cerebellar Mutism

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Bromocriptine for the treatment of postoperative cerebellar mutism syndrome in pediatric patients: Three case reports

Journal of Oncology Pharmacy Practice ◽

10.1177/1078155220982046 ◽

2020 ◽

pp. 107815522098204

Author(s):

Miguel Á Amor-García ◽

Cecilia M Fernández-Llamazares ◽

Silvia Manrique-Rodríguez ◽

Álvaro Narrillos-Moraza ◽

Marina García-Morín ◽

...

Keyword(s):

Posterior Fossa ◽

Low Dose ◽

Pediatric Patients ◽

Case Reports ◽

Tumor Resection ◽

Posterior Fossa Tumor ◽

Cerebellar Mutism ◽

Common Complication ◽

Minimum Effective Dose ◽

Biological Origin

Introduction Cerebellar mutism syndrome (CMS) is a common complication after posterior fossa tumor resection. It is characterized by a significant lack or loss of speech. Its biological origin remains unclear and there are no standardized treatments. However, bromocriptine seems to be a possible treatment for this condition. Case report In this paper, we present three cases of pediatric patients (4, 5, and 17-year old) who developed CMS after posterior fossa tumor surgery. They were treated with bromocriptine to improve neurological symptoms. Management and outcome: Bromocriptine was started at a low dose and was progressively increased to reach the minimum effective dose. After four months of treatment, a normal and fluid speech was observed in the three patients. No discontinuation due to adverse events were reported. Discussion Bromocriptine has shown to be an effective and safe treatment for CMS in pediatric patients after posterior fossa tumor resection.

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Postoperative Pediatric Cerebellar Mutism After Posterior Fossa Surgery

A & A Case Reports ◽

10.1213/xaa.0000000000000467 ◽

2017 ◽

Vol 8 (8) ◽

pp. 213-215

Author(s):

Jerry Y. Chao ◽

Che Liu ◽

Naveen Shetty ◽

Ushma Shah

Keyword(s):

Posterior Fossa ◽

Posterior Fossa Surgery ◽

Cerebellar Mutism

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