Cause and outcome of cerebellar mutism: evidence from a systematic review.

PURPOSE: Cerebellar mutism is a serious neurosurgical complication after posterior fossa surgery, but the cause, incidence and outcome remain incompletely defined. The aim of this paper was to identify and review all reports of this phenomenon to better delineate and improve the evidence base. METHODS: A systematic search and retrieval of databases was conducted using advanced search techniques. Review/outcomes criteria were developed, and study quality was determined. RESULTS: The retrieval identified 2,281 papers of which 96 were relevant, identifying 650 children with cerebellar mutism. Causative factors, clinical features and outcomes were reported variably; papers focussed on multiple areas, the majority reporting incidence in single or series of case studies with little or no analysis further than description. CONCLUSIONS: The complexity and variability of data reporting, likely contributing factors and outcomes make cerebellar mutism difficult to predict in incidence and the degree of impact that may ensue. A clear and accepted universal definition would help improve reporting, as would the application of agreed outcome measures. Clear and consistent reporting of surgical technique remains absent. Recommendations for practice are provided.

Language outcomes in children who underwent surgery for the removal of a posterior fossa tumor: A systematic review.

BACKGROUND: Children who underwent posterior fossa tumor removal may have spoken or written language impairments. The present systematic review synthesized the literature regarding the language outcomes in this population. Benefits of this work were the identification of shortcomings in the literature and a starting point toward formulating guidelines for postoperative language assessment. METHODS: A systematic literature search was conducted, identifying studies with patients who had posterior fossa surgery before 18 years of age. Included studies were narratively synthesized to understand language outcomes by language function (e.g., phonology, morphosyntax) at a group and individual level. Furthermore, the influence of several mediators (e.g., postoperative cerebellar mutism syndrome (pCMS), tumor type) was investigated. A critical evaluation of the language assessment tools was conducted. RESULTS: The narrative synthesis of 66 studies showed that a broad spectrum of language impairments has been described, characterized by a large interindividual heterogeneity. Patients younger at diagnosis, receiving treatment for a high-grade tumor and/or radiotherapy and diagnosed with pCMS seemed more prone to impairment. Several gaps in language assessment remain, such as a baseline preoperative assessment and the assessment of pragmatics and morphosyntax. Further, there were important methodological differences in existing studies which complicated our ability to accurately guide clinical practice. CONCLUSION: Children who had posterior fossa surgery seem to be at risk for postoperative language impairment. These results stress the need for language follow-up in posterior fossa tumor survivors.

Transcerebellomedullary fissure approach to lesions of the fourth ventricle: less is more?

BACKGROUND: The transcerebellomedullary fissure (trans-CMF) approach is safe and effective. Nevertheless, previous research documented a few differences in the use of this approach with regard to the opening portion of the fissure and roof of the ventricle. Here, we present a series of patients with fourth ventricular lesions and our experience using the trans-CMF approach. METHODS: Fifty patients who underwent the trans-CMF approach were analyzed. The tela choroidea was simply incised in 32 patients: 27 unilaterally and 5 bilaterally. Both the tela and inferior medullary velum were cut in 18 patients: 16 unilaterally and 2 bilaterally. Unless the tumor extended below the C1 level, C1 was preserved intact. Brainstem mapping (BSM) and corticobulbar tract (CBT) motor-evoked potential (MEP) monitoring were used. RESULTS: Gross total removal was achieved in 41 (82 %) cases, and sub-total removal was achieved in 9 (18 %) cases. Two deaths occurred 1-2 months postoperatively because of pulmonary complications. Four patients developed temporary mutism, all of whom underwent the bilateral trans-CMF approach (this rate is significantly higher than that of the unilateral approach, P < 0.05). No permanent neurological deficit occurred. CONCLUSION: The trans-CMF approach provides excellent access to fourth ventricular lesions without splitting the vermis. The opening portion of the fissure and roof of the ventricle should be determined by the location, extension and size of the lesion. In most cases, the unilateral trans-CMF approach with only a tela choroidea incision is adequate; this procedure is mini-invasive and possibly prevents postoperative mutism.

Negative motor seizure arising from the negative motor area: is it ictal apraxia?

PURPOSE: Seizure manifesting motor arrest, that is, negative motor seizure (NMS), is a rare epileptic condition in which only inability to conduct voluntary movements or praxis is produced, although consciousness is preserved. The negative motor area (NMA) seems to be responsible, but its generator mechanism has not yet been clarified. PATIENTS AND METHODS: Three patients manifesting NMS were investigated. Two patients (ages 33 and 17) with intractable frontal lobe epilepsy had subdural grid implantation for epilepsy surgery, and one (age 77) had scalp electroencephalography (EEG) monitoring. RESULTS: Ictal semiologies commonly observed, at least in the two patients, were found as follows; (1) indescribable or ill-localized aura, (2) repetitive involuntary vocalization, (3) inability to speak, (4) inability to move the extremities, and (5) subsequent evolution to positive motor seizures. Awareness and comprehension were preserved throughout the episode before generalized seizures. In two patients with epicortical EEG recording, ictal activity arose from the lateral NMA in one, and from the rostral supplementary motor area in the other. Cortical stimulation at NMA in one patient elicited symptoms identical to NMS. Another patient had scalp EEG and magnetic resonance imaging (MRI) abnormality, both suggesting the epileptogenic focus in the mesial frontal area. CONCLUSION: We showed that (1) NMS was a rare condition in patients with seizure focus in the frontal lobe, and (2) that the NMA was responsible for the symptoms. The documented state in the present study may reflect ictal apraxia, but it requires further investigation.

Reversal of lifelong mutism after anterior cervical discectomy and fusion for myelopathy.

A 34-year-old man with a history of spina bifida occulta, fetal alcohol syndrome and mutism presented with an acute on chronic decline of unsteady gait and right arm and leg weakness over the period of a few months. The patient was non-verbal and communicated using hand gestures. MRI of the cervical spine showed severe stenosis at C4-5 with T2 signal abnormalities. Brain MRI demonstrated mild ventriculomegaly. The patient underwent an anterior cervical discectomy and fusion for severe cervical spine stenosis. Postoperatively the patient's myelopathic symptoms improved. He also became verbal and engaged in conversation. Ten months after surgery, the patient who had previously been non-verbal had developed a vocabulary of more than 50 words.

Mutism after posterior fossa tumour resection in children: incomplete recovery on long-term follow-up.

INTRODUCTION: Mutism after posterior fossa tumour resection is generally said to be transient. Our experience suggested that speech did not usually normalise, and that mutism was associated with neurologic deficits that did not recover fully. METHODS: Children with mutism after posterior fossa tumour resection, and alive more than 2 years post-operatively, were reviewed retrospectively. Charts were reviewed and parents contacted to ascertain details about mutism, associated neurologic deficits, and the most recent speech and neurologic status. RESULTS: There were 7 children, with follow-up ranging from 2.5 to 13.1 years (mean 6.8 years). Tumours were midline, with 4 astrocytomas and 3 medulloblastomas. Mutism was noted immediately after post-operative extubation in all patients. Speech reappeared 1-15 weeks post-operatively, except for 1 patient, who remained mute at 2.5 years. Speech returned to normal in only 1 patient. Mutism was always accompanied by new or worsened cerebellar ataxia, which resolved incompletely in the long term. Sixth nerve palsies occurred in 3 and recovered incompletely. Seventh nerve paresis occurred in 2 and recovered completely. CONCLUSION: Mutism after posterior fossa tumour resection is associated with other neurologic deficits, particularly ataxia. Whereas speech usually returns, contrary to general opinion, speech rarely normalises. Other associated deficits rarely resolve completely. These findings have significant implications for counselling of family and patients.