Intraoperative Mapping of the Sensory Root of the Trigeminal Nerve in Patients with Pontocerebellar Angle Pathology

OBJECTIVE

The aim of the present study was to determine the position of the 3 sensory branches of the trigeminal nerve in the preganglionic tract using intraoperative neurophysiological mapping.

METHODS

We included consecutive adult patients who underwent neurosurgical treatment of cerebellopontine angle lesions. The trigeminal nerve was antidromically stimulated at 3 sites along its circumference with different stimulus intensities at a distance of ≤1 cm from the brainstem. The sensory nerve action potentials (SNAPs) were recorded from each main trigeminal branch (V1 [ophthalmic branch], V2 [maxillary branch], and V3 [mandibular branch]).

RESULTS

We analyzed 13 patients. The stimulation points at which we obtained the greatest number of congruous and exclusive SNAPs (SNAPs only on the stimulated branch) was the stimulation point for V3 (20.7%). The stimulation intensity at which we obtained the highest number of congruent and exclusive SNAPs with the stimulated branch was 0.5 mA.

CONCLUSIONS

Using our recording conditions, trigeminal stimulation is a reliable technique for mapping the V3 and V1 branches using an intensity not exceeding 0.5. However, reliable identification of the fibers of V2 is more difficult. Stimulation of the trigeminal nerve can be a reliable technique to identify the V3 and V1 branches if rhizotomy of these branches is necessary.

Is the Patient State Index a reliable parameter as guide to anaesthesiology in cranial neurosurgery? A first intraoperative study and a literature review

BACKGROUND

Patient State Index (PSI) and Suppression Ratio (SR) are two indices calculated by quantitative analysis of EEG used to estimate the depth of anaesthesia but their validation in neurosurgery must be done. Our aim was to investigate the congruity PSI and SR with raw EEG monitoring in neurosurgery.

METHODS

We included 34 patients undergoing elective cranial neurosurgery. Each patient was monitored by a SedLine device (PSI and SR) and by raw EEG. To appraise the agreement between PSI, SR and EEG Suppr%, Bland-Altman analysis was used. We also correlated the PSI and SR recorded at different times during surgery to the degree of suppression of the raw EEG data by Spearman's rank correlation coefficient. For a comparison with previous data we made an international literature review according to PRISMA protocol.

RESULTS

At all recording times, we found that there is a strong agreement between PSI and raw EEG. We also found a significant correlation for both PSI and SR with the EEG suppression percentage (p < 0.05), but with a broad dispersion of the individual values within the confidence interval.

CONCLUSION

The Masimo SedLine processed EEG monitoring system can be used as a guide in the anaesthetic management of patients during elective cranial neurosurgery, but the anaesthesiologist must be aware that previous correlations between PSI and SR with the suppression percentage may not always be valid in all individual patients. The use of an extended visual raw EEG evaluated by an expert electroencephalographer might help to provide better guidance.

Feasibility of Intraoperative Visual Evoked Potential Monitoring by Cortical Strip Electrodes in Patients During Brain Surgery: A Preliminary Study

OBJECTIVE

The role of visual evoked potentials (VEPs) monitoring during neurosurgical procedure in patient remains unclear. The purpose of our study was to determine the feasibility of intraoperative VEP recording using a strip cortical electrode during surgical resection of intracranial lesions.

METHODS

In this prospective, monocentric, observational study, we enrolled consecutive patients undergoing neurosurgical procedure for intracranial lesions. After dural opening, a cortical strip was positioned on the lateral occipital surface. Flash VEPs were continuously recorded using both subdermal corkscrew electrodes and strip electrodes. An electroretinogram was also recorded to guarantee delivery of adequate flash stimuli to the retina.

RESULTS

We included 10 patients affected by different intracranial lesions. Flash VEPs were recorded using subdermal corkscrew electrodes in all patients except 1 in whom they were never identified during the recording. Flash VEPs were recorded using strip electrodes in all patients and showed a polyphasic morphology with a significantly larger amplitude compared with that of flash VEPs measured using subdermal corkscrew electrodes. No patient reported worsened postoperative vision and a >50% decrease in the VEPs amplitude was never registered.

CONCLUSIONS

We have reported for the first time in the literature that VEP monitoring during a neurosurgical procedure is feasible via a cortical strip located on the occipital surface. The technique demonstrated greater stability and a larger amplitude compared with recordings with scalp electrodes, facilitating identification of any changes. Studies with more patients are needed to assess the clinical reliability of the technique.

Neurophysiology of the pelvic floor in clinical practice: a systematic literature review

Neurophysiological testing of the pelvic floor is recognized as an essential tool to identify pathophysiological mechanisms of pelvic floor disorders, support clinical diagnosis, and aid in therapeutic decisions. Nevertheless, the diagnostic value of these tests in specific neurological diseases of the pelvic floor is not completely clarified. Seeking to fill this gap, the members of the Neurophysiology of the Pelvic Floor Study Group of the Italian Clinical Neurophysiology Society performed a systematic review of the literature to gather available evidence for and against the utility of neurophysiological tests. Our findings confirm the utility of some tests in specific clinical conditions [e.g. concentric needle electromyography, evaluation of sacral reflexes and of pudendal somatosensory evoked potentials (pSEPs) in cauda equina and conus medullaris lesions, and evaluation of pSEPs and perineal sympathetic skin response in spinal cord lesions], and support their use in clinical practice. Other tests, particularly those not currently supported by high-level evidence, when employed in individual patients, should be evaluated in the overall clinical context, or otherwise used for research purposes.

Effects of Class II-Selective Histone Deacetylase Inhibitor on Neuromuscular Function and Disease Progression in SOD1-ALS Mice

Emerging evidence indicates that transcriptome alterations due to epigenetic deregulation concur to ALS pathogenesis. Accordingly, pan-histone deacetylase (HDAC) inhibitors delay ALS development in mice, but these compounds failed when tested in ALS patients. Possibly, lack of selectivity toward specific classes of HDACs weakens the therapeutic effects of pan-HDAC inhibitors. Here, we tested the effects of the HDAC Class II selective inhibitor MC1568 on disease evolution, motor neuron survival as well as skeletal muscle function in SOD1G93A mice. We report that HDACs did not undergo expression changes during disease evolution in isolated motor neurons of adult mice. Conversely, increase in specific Class II HDACs (-4, -5 and -6) occurs in skeletal muscle of mice with severe neuromuscular impairment. Importantly, treatment with MC1568 causes early improvement of motor performances that vanishes at later stages of disease. Notably, motor improvement is not paralleled by reduced motor neuron degeneration but by increased skeletal muscle electrical potentials, reduced activation of mir206/FGFBP1-dependent muscle reinnervation signaling, and increased muscle expression of myogenic genes.

Proposal of a New Criterion for Electrodiagnosis of Meralgia Paresthetica by Evoked Potentials

We examined 19 subjects with meralgia paresthetica (bilateral in three cases), recording bilateral somatosensory-evoked potentials (SSEPs) after stimulation of the tibial posterior nerve (TPN) and cutaneous stimulation in the region of the lateral femoral cutaneous nerve (LFCN). We calculated the difference between TPN SSEPs and LFCN SSEPs cortical potentials, identifying a temporal parameter that we termed D(SEP). We defined D(SEP) normal values in a control group. D(SEP) evaluation showed good sensitivity and specificity (85.7% and 82.4%, respectively; accuracy, 83.3%) in discriminating affected limbs from unaffected. The main advantage of this method is to disengage from the necessity of contralateral comparison of LFCN recordings, joined with a reduction of interindividual variability of LFCN SSEPs amplitude and latency that often causes a lower sensitivity of other methods. As an interesting consideration, D(SEP) evaluation appears to mark out a possible subclinical involvement of LFCN in the asymptomatic side of patients with meralgia paresthetica.

Autonomic nerve dysfunction in pathologically obese patients

BACKGROUND

Obese patients frequently present clinical symptoms related to gastrointestinal motility alterations and autonomic nervous system dysfunction.

AIM

To evaluate the possible correlation between cardiovascular autonomic nervous dysfunction and oesophageal motility in pathologically obese patients.

PATIENTS AND METHODS

Enrolled in the study were 22 patients with a body mass index of 45.72 +/- 7.48 and 10 control subjects, all within 20% of their ideal weight. Oesophageal motility was measured by stationary manometry and scintigraphic transit. Tests for the evaluation of autonomic nervous system were: Valsalva ratio, deep breathing, sustained handgrip, sudormotor axon reflex test and spectral analysis of the variability of R-R interval.

RESULTS

The mean pressure of oesophageal peristaltic waves in patients and controls was 39.36 +/- 14 mmHg and 73 +/- 12 mmHg, respectively The scintigraphic mean transit time was 22.96 +/- 16.26 seconds in patients and 10.23 +/- 16.26 seconds in controls (p < 0.001). Spectral analysis of the variability of the R-R interval showed an increase in the parasympathetic component both in the lying and standing position compared to controls. The other autonomic nervous system function tests showed no significant difference between obese patients and controls.

CONCLUSIONS

These results suggest that obese patients present a reduction of oesophageal transit and autonomic nervous system dysfunction albeit no direct correlation was found between these phenomena.

Ability and fitness to drive of Parkinson's disease patients

The authors review reports in the literature on the fitness and ability to drive of neurosurgical patients and subjects afflicted by neurological disorders, before focusing on their own series of 204 idiopathic Parkinson's disease (PD) patients. The study sample comprised 173 men and 31 women (average age 70.6 and 74.2 years, respectively) of whom 51, for various reasons, still drove (albeit only short distances). Different variables were examined (Hoehn & Yahr scale values (of the total group and of the subgroup of active drivers), scores for various clinical diseases, and so on) looking for an association between these variables and the number of accidents incurred by PD patients as compared with the healthy population and with a control group of healthy age-matched subjects (ISTAT data). The need for adequate legislation on driving in PD emerges clearly and recommendations are given on which such legislation might be based.

[Nonpsychotic involutional inhibited depressions and psycho-organic deteriorations: treatment with Viloxazine and piracetam]

Involutional depression is often the first symptom of a psycho-organic syndrome or dementia and may not present overt symptoms itself; these depressive states have been variously classified by different schools in various countries. The hypothesis of catecholamine and indolamine in the aetiopathogenic agent is oversimplistic and the theory that abnormal receptor hypersensitivity is the cause of the condition is more convincing. On the basis of this hypothesis numerous studies have been conducted into the efficacy of various antidepressants in the treatment of this hypersensitivity. Involutional depressions are more common among women and are found in about 10% of 60-65 year olds. This report claims that combined viloxazine-piracetam is the most appropriate treatment for involutional depression. This approach (200 mg oral viloxazine and 9 g oral piracetam a day) was adopted for 3 months in 33 out patients about 64 years old who were subsequently put on maintenance doses (100 mg viloxazine, 3 g piracetam a day). The various Hamilton scale parameters were assessed as were reaction times to auditory and visual simple stimuli. Result sat the start and end of treatment were then compared. About three quarters of the patients showed improvement in both depression and psycho-organic syndrome symptoms, while total remission or lasting improvement in both pathologies was obtained in about 50%.

Operatory indications and licence of craniostenosis

On average 0.04% of the population is affected by craniostenosis. It is believed there are anatomo-clinical forms at moderate risk and others at high risk. The neurosurgical indications are very different according to various Authors. The forms at high risk which are caused by an isolated synostosis of the coronal system with brachicephalia are either associated to other synostosis (oxicephalia) or to facial synostosis should always be operated, with various techniques, within the first 6 months of life. Basing on the experience of 3 cases of craniostenosis, deliberately not operated on, followed and controlled for over 20 years from the decision of not to operate, all in excellent general condition both neurological and psychiatric, the Authors consider and discuss the criteria of surgical indications with particular regard to clinical objectivity (implicity disregarding a precise value of the craniometric data).

[Neurotraumatology and post-traumatic epilepsy. Prevention, treatment and long-term follow-up. Barbexaclone + phenobarbital (maliasin) versus diphenylhydantoin, phenobarbital, primidone, carbamazepine]

A report is presented on 58 patients (46 males, 12 females) all suffering from post-traumatic epilepsy (PTE) and followed up for a minimum of 1 year to maximum of 23 years after the injury (mean 6.3 years). The type and site of the head injury, the nature of the brain lesions, the time elapsing before the first critical manifestation, the clinical character of the epileptic attacks, EEG, cerebral CAT and RMN data were performed are given for all patients. The therapeutic and prophylactic strategies adopted are then described in detail with particular emphasis on the use of diphenylhydantoin (DPH) and barbexaclone. The latter drug, used for the last 3 years was found to be particularly useful in the treatment of patients suffering from a post-traumatic psycho-organic syndrome in addition to the PTE.