Identifying functional cortical plasticity after spinal tumour resection using navigated transcranial magnetic stimulation.

Our aim was to investigate the effectiveness of navigated transcranial magnetic stimulation (nTMS) brain mapping to characterise preoperative motor impairment caused by an intradural extramedullary (IDEM) tumour and postoperative cortical functional reorganisation. Preoperative and 1-year follow-up clinical, radiological and nTMS data from a case of thoracic spinal meningioma that underwent surgical resection of the lesion were collected and compared. A 67-year-old patient presented with severe progressive thoracic myelopathy (hypertonic paraparesis, clonus, insensate urinary retention) secondary to an IDEM tumour. Initial nTMS assessment showed bilateral upper limb representation with no positive responses for both lower limbs. He underwent successful surgical resection for his IDEM (meningioma WHO grade 1). At 1-year follow-up, the patient's gait was improved and his bladder function normalised. nTMS documented positive responses for both upper and lower limbs and a decrease in the area (right side: 1.01 vs 0.39cm2; left side: 1.92 vs 0.81cm2) and volume (right side: 344.2 vs 42.4uVcm2; left side: 467.1 vs 119uVcm2) of cortical activation for both upper limbs, suggesting a functional reorganisation of the motor areas after tumour resection. nTMS motor mapping and derived metrics can characterise preoperative motor deficit and cortical plasticity during follow-up after IDEM resection.

Reliability of Intraoperative Monitoring in Patients with a Preexisting Motor Deficit: Case Report and Literature Review.

BACKGROUND: The use of intraoperative monitoring (IOM) in glioma surgery is a widely adopted and clinically validated adjunct to define safe zones of resection for the neurosurgeon. However, the role of IOM in cases of a significant preexisting motor deficit is questionable. CASE DESCRIPTION: We describe a case of a 25-year-old with a recurrent presentation of a left paracentral glioblastoma, admitted with intratumoral hemorrhage and subsequent acute severe right-sided weakness. The patient underwent a redo left parietal craniotomy and 5-aminolevulinic acid-guided resection with IOM. The severity of the weakness was not reflected by the pre- and intraoperative cortical motor evoked potentials (MEPs) that were reassuring. The patient's hemiparesis recovered to full power postoperatively. CONCLUSIONS: Preoperative weakness is traditionally accepted as a relative contraindication to IOM and therefore its usefulness is questioned in this context. Our case challenges this assumption. We present the clinical course, review the cranial and spinal literature including the reliability of IOM in cases of preoperative motor deficit, and discuss the need for tailor-made IOM strategies.

Using telephone logs instead of databases to accurately estimate neurosurgical on-call workload.

BACKGROUND: Maintenance of on-call referrals databases is on the rise in neurosurgical units across the UK and helps provide data to estimate workload. We hypothesize that these databases underestimate the workload and propose the use of the number of telephone calls to the on-call registrar as an easily obtainable and valid measure of workload. METHODS: Data were obtained from a referrals database maintained and completed by the neurosurgical registrars and the hospital switchboard telephone logs. Data were analysed using JMP 8.0.2 (SAS Institute, Cary, NC). RESULTS: We found a large degree of disparity between the number of phone calls and the number of recorded referrals. The median number of phone calls to the on-call registrar per day was 78 (Interquartile range 59-106); but the median number of recorded referrals was 12 (Interquartile range 8-16). 49.8% of the calls were received out-of-hours (1700-0800 and weekends) and the maximum number of calls was received on a Friday. Data derived from both sources (database and switchboard logs) showed a close visual correlation. CONCLUSION: We argue that on-call logs are an easily obtainable, reliable and internally validated measure of activity. We recommend the use of such data in other centers to establish the nature of on-call activity and tailoring of the rotas to comply with current guidance to provide a mix of service and training.

Venous outflow as a criterion of impairment of cerebral vascular reserve.

AIM: The purpose of this work is to evaluate if the asymmetry of venous outflow between the two hemispheres is a reliable criterion of impairment of the cerebral vascular reserve among symptomatic patients harbouring a spontaneous atherosclerotic occlusion of internal carotid artery. METHODS: From January 1995 to December 2007, 7 symptomatic patients, affected from occlusion of internal carotid artery, were submitted to a low-flow by-pass between the superficial temporal artery and the middle cerebral artery owing to the presence of an impairment of cerebral vascular reserve diagnosed by TC-Doppler, SPECT or perfusion-CT with acetazolamide challenge. Conventional angiography was always performed. Angiographic studies of these patients were reviewed in order to find out the presence of asymmetry of the venous outflow. In the same period 35 patients harbouring an occlusion of the carotid artery in the neck and a normal cerebral reserve underwent cerebral angiography in our departments in Monza. Angiographic studies, of this latter group of patients, were also retrospectively analyzed with the same purpose. RESULTS: All patients, with a poor cerebral reserve, showed an asymmetry of venous outflow >3 s omolateral at the carotid occlusion. Patients, with a normal cerebral reserve, showed an asymmetry of venous outflow <2 s. CONCLUSIONS: Asymmetry of venous outflow were correlated to an impaired cerebral reserve also in chronic conditions as atherosclerotic spontaneous occlusion of internal carotid artery. Our data are a further support to the reliability of this criterion in case of therapeutic sacrifice of internal carotid artery.

Cerebral activity modulation by extradural motor cortex stimulation in Parkinson's disease: a perfusion SPECT study.

Extradural motor cortex stimulation (EMCS) has been proposed as alternative to deep brain stimulation (DBS) in the treatment of Parkinson's disease (PD). Its mechanisms of action are still unclear. Neuroimaging evidenced motor cortical dysfunction in PD that can be reversed by therapy. We performed left hemisphere EMCS surgery in six advanced PD patients fulfilling CAPSIT criteria for DBS with the exception of age >70 years. After 6 months, we measured regional cerebral blood flow (rCBF) at rest with SPECT and Tc-99m cysteinate dimer bicisate off-medication with stimulator off and on. Clinical assessment included Unified Parkinson's Disease Rating Scale part II and III, Abnormal Involuntary Movement Scale and mean dopaminergic medication dosage. We used statistical parametric mapping for imaging data analysis. Clinically we observed no mean changes in motor scales, although blinded evaluation revealed some benefit in individual patients. We found significant rCBF decrements in the pre-central gyrus, pre-motor cortex and caudate nucleus bilaterally, left prefrontal areas and right thalamus. Perfusion increments were found in cerebellum bilaterally. EMCS determined significant modulation of neuronal activity within the cortico-basal ganglia-thalamo-cortical motor loop in our cohort of advanced PD patients. However, these effects were paralleled by mild and variable clinical efficacy.

Combined transcranial and endoscopic nasal resection for esthesioneuroblastoma. Technical note.

Esthesioneuroblastoma is a rare malignant neoplasm arising in the nasal cavity. Huge esthesioneuroblastomas, extending into the ethmoid roof and the cribriform plate, or invading the anterior cranial fossa, have traditionally been treated by craniofacial resection. Because of the invasiveness and potentially disfiguring results of a transfacial approach, a new technique has been proposed, combining endoscopic nasal and anterior craniotomy resection. We describe the case of a young male presenting with a large esthesioneuroblastoma involving the nasal cavity and the anterior cranial fossa, causing a huge skull base destruction. A combined transcranial and endoscopic nasal resection resulted in a macroscopically total removal of the tumor. The operative technique is reviewed in detail, along with the method used for the reconstruction of the anterior skull base defect.

Clinical correlates and cognitive underpinnings of verbal fluency impairment after chronic subthalamic stimulation in Parkinson's disease.

A decline in verbal fluency is the most consistent neuropsychological sequela of deep brain stimulation (DBS) for Parkinson's disease. We assessed clinical correlates and switching and clustering subcomponents in 26 parkinsonians undergoing subthalamic DBS. Post-surgical motor improvement was accompanied by worsening at both letter and category fluency tasks. Total number of words and switches decreased, while average cluster size was unchanged. Worsening tended to be prominent in patients with baseline poorer cognitive status and more depressed mood. Impairment of shifting suggests prefrontal dysfunction, possibly due to disruption of fronto-striatal circuits along the surgical trajectory and/or to high frequency stimulation itself.

The headache in the Emergency Department.

The headache is a very frequent symptom and represents the 0.36%-2.5% of all reasons of claim to Emergency Department. Even if it is rarely related to high risk diseases, it is mandatory to promptly differentiate life-threatening conditions. In order to establish a correct diagnostic and therapeutic pathway and ask for aimed specialistic consultation, the emergency physician must be familiar with the various categories of headache. It is important to distinguish between essential headache and secondary headache. All patients presenting to the emergency department with the complaint of headache should be interviewed carefully regarding their history. The quality of pain associated with the intensity, location, rate, duration, modality of onset, relieving or worsening conditions, response to drugs, symptoms or signs associated must be investigated as well. Careful neurological examination including the vision of fundus oculi and the evaluation of rigor nucalis can provide further important diagnostic information. Laboratory exams do not usually give significant issues in the majority of patients with headache. However, dosage of inflammation index can be useful when an infective or inflammatory disease is suspected. CT scan can rule-out the suspicion of organic intracranial causes. When the physician suspects meningitis or subarachnoid hemorrhage (SAH) not showed by CT scanning, rachicentesis can turn out diagnostic. The modality of onset, clinical characteristics and differential diagnosis of subarachnoid hemorrhage, intracranial hypertension, colloidal cyst of the third ventricle, trigeminal neuralgia, temporal arteritis and pituitary adenomas and apoplexy will be discussed. These diseases are not only of neurological and neurosurgical interest, but involve also the physician in the Emergency Department.