Integrative approaches in spinal cord stimulation: Neuropathic pain management and motor recovery in spinal cord injury. A narrative review.

Introduction: Spinal cord stimulation is a widespread treatment of chronic neuropathic pain from different conditions. Several novel and improving technologies have been recently developed to increase the effect of neuromodulation in patients refractory to pharmacological therapy. Research question: To explore spinal cord stimulation's mechanisms of action, indications, and management. Material and methods: The paper initially explores the mechanism of action of this procedure based on the generation of an electric field between electrodes placed on the posterior dural surface of the spinal cord probably interfering with the transmission of pain stimuli to the brain. Subsequently, the most consolidated criteria for selecting patients for surgery, which constitute a major issue of debate, were defined. Thereafter, the fundamental patterns of stimulation were summarized by exploring the advantages and side effects. Lastly, the most common side effects and the related management were discussed. Results: Proper selection of the patient is of paramount importance to achieve the best results from this specific neuromodulation treatment. Regarding the different types of stimulation patterns, no definite evidence-based guidelines exist on the most appropriate approach in relation to the specific type of neuropathic pain. Both burst stimulation and high-frequency stimulation are innovative techniques that reduce the risk of paresthesias compared with conventional stimulation. Discussion and conclusion: Novel protocols of stimulation (burst stimulation and high frequency stimulation) may improve the trade-off between therapeutic benefits and potential side effects. Likewise, decreasing the rates of hardware-related complications will be also useful to increase the application of neuromodulation in clinical settings.

Effect of age on metabolomic changes in a model of paclitaxel-induced peripheral neurotoxicity.

BACKGROUND AND AIMS: Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of the most common dose-limiting side effects of paclitaxel (PTX) treatment. Many age-related changes have been hypothesized to underlie susceptibility to damage or impaired regeneration/repair after nerve injury. The results of these studies, however, are inconclusive and other potential biomarkers of nerve impairment need to be investigated. METHODS: Twenty-four young (2 months) and 24 adult (9 months) Wistar male rats were randomized to either PTX treatment (10 mg/kg i.v. once/week for 4 weeks) or vehicle administration. Neurophysiological and behavioral tests were performed at baseline, after 4 weeks of treatment and 2-week follow-up. Skin biopsies and nerve specimens collected from sacrificed animals were examined for intraepidermal nerve fiber (IENF) density assessment and nerve morphology/morphometry. Blood and liver samples were collected for targeted metabolomics analysis. RESULTS: At the end of treatment, the neurophysiological studies revealed a reduction in sensory nerve action potential amplitude (p < .05) in the caudal nerve of young PTX-animals, and in both the digital and caudal nerve of adult PTX-animals (p < .05). A significant decrease in the mechanical threshold was observed only in young PTX-animals (p < .001), but not in adult PTX-ones. Nevertheless, both young and adult PTX-rats had reduced IENF density (p < .0001), which persisted at the end of follow-up period. Targeted metabolomics analysis showed significant differences in the plasma metabolite profiles between PTX-animals developing peripheral neuropathy and age-matched controls, with triglycerides, diglycerides, acylcarnitines, carnosine, long chain ceramides, sphingolipids, and bile acids playing a major role in the response to PTX administration. INTERPRETATION: Our study identifies for the first time multiple related metabolic axes involved in PTX-induced peripheral neurotoxicity, and suggests age-related differences in CIPN manifestations and in the metabolic profile.

Small spheno-ethmoidal meningoencephalocele versus ethmoidal mucocele in spontaneous intracranial hypotension.

Background: Meningoencephalocele is defined as an abnormal sac of brain tissue and meninges extending beyond natural skull margins, often leading to cerebrospinal fluid (CSF) leakage. When this condition arises in the spheno-ethmoidal region, the diagnosis becomes more challenging as it can be mistaken for other nasal pathologies, such as mucocele. Research question: We show in this case report a non-congenital sphenoethmoidal meningoencephalocele causing rhinoliquoral fistula and spontaneous intracranial hypotension. Results: this 65-year-old woman presented with sporadic rhinoliquorrhoea associated with orthostatic headache, nausea and dizziness. Brain MRI revealed a small lesion of an ethmoidal sinus, which was successfully treated with endoscopic endonasal surgery. Histology confirmed the presence of meningoencephalic tissue positive for S100 protein on immunohistochemistry. Conclusions: When dealing with lesions of the paranasal sinuses in contact with the anterior skull base, rhinoliquorrhoea presence suggests meningoencephalocele. In dubious cases, a proper workup, including a thorough clinical history and neurological examination, specific imaging, and a direct search of CSF-like markers, is essential to support the differential diagnosis. In such cases, a transnasal endoscopic surgical approach is recommended to obtain a final histological diagnosis and to perform eventual dural plastic surgery.

Occipital Intradiploic Pseudomeningocele - A Rare Complication of Pediatric Posterior Cranial Fossa Surgery: Case Report and Review of the Literature.

INTRODUCTION: Intradiploic pseudomeningoceles, also called intradiploic cerebrospinal fluid (CSF) fistulas, are abnormal CSF collections between the two bony tables of the calvaria resulting from postsurgical CSF leakage. To date, only six cases of intradiploic pseudomeningocele have been reported, all occurring in the occipital area. In this paper, we report the seventh case of late-onset occipital intradiploic pseudomeningocele (OIP) occurring in a young female patient who underwent surgery for the removal of a cerebellar pilocytic astrocytoma. In this regard, we also review the literature on the few recognized cases of OIP. CASE PRESENTATION: The case of an 18-year-old female patient known to our institute for an operation 12 years earlier to remove a pilocytic astrocytoma is illustrated. At admission, the patient complained only of occasional orthostatic headache. Brain imaging demonstrated a pseudomeningocele extended intradiploically from the occipital squama to the condylar and clivus regions, thinning both occipital bone tables and dilating the CSF-filled diploe. Watertight duroplasty and cranioplasty were effectively performed. CONCLUSION: Pediatric patients undergoing posterior cranial fossa craniotomy/craniectomy may postoperatively develop OIP. In this setting, treatment of any dural CSF fistula should be considered because of the risk of progressive extension and bone erosion.

Diagnostic approach, therapeutic strategies, and surgical indications in intradural thoracic disc herniation associated with CSF leak, intracranial hypotension, and CNS superficial siderosis.

BACKGROUND AND PURPOSE: Intradural disc herniation (IDH) can manifest with radicular or medullary syndrome. In about 15% of cases, IDH may be responsible, through a dural laceration, for a CSF leak, determining spontaneous intracranial hypotension (SIH) and CNS superficial siderosis (CNSss). This paper attempts to present an overview on IDH as the cause for both CSF leak, and subsequent SIH, and CNSss, and to describe a peculiar clinical and neuroradiological scenario related to this condition. METHODS: A search on the PUBMED database was performed. Although the investigation did not rigorously follow the criteria for a systematic review (we consider only articles about thoracic IDH), nonetheless, the best quality evidence was pursued. Furthermore, an illustrative case was presented. RESULTS: A 69-year-old woman was referred to our hospital for slowly progressive gait disturbances and hearing impairment. Brain imaging revealed diffuse bilateral supratentorial and infratentorial superficial siderosis, mostly of the cerebellum, the eighth cranial nerves, and the brainstem. Spinal imaging disclosed a posterior disc herniation determining a dural tear at D6-D7. Lumbar puncture revealed low opening pressure and hemorrhagic CSF with siderophages. A posterior transdural herniectomy and dural sealing determined a stabilization of hearing and a significant improvement in both gait and balance. CONCLUSIONS: The diagnostic workup of CNSss with suspected CNS leak demands whole neuraxis imaging, especially in cases presenting SIH or myelopathic symptoms. This may avoid delays in detection of IDH and spinal dural leaks. The different forms of treatment available depend on the type and severity of the clinical picture.

Deep brain stimulation in Huntington's disease: a literature review.

BACKGROUND: Huntington's disease (HD) is a neurodegenerative disorder characterized by involuntary movements, cognitive decline, and behavioral changes. The complex constellation of clinical symptoms still makes the therapeutic management challenging. In the new era of functional neurosurgery, deep brain stimulation (DBS) may represent a promising therapeutic approach in selected HD patients. METHODS: Articles describing the effect of DBS in patients affected by HD were selected from Medline and PubMed by the association of text words with MeSH terms as follows: "Deep brain stimulation," "DBS," and "HD," "Huntington's disease," and "Huntington." Details on repeat expansion, age at operation, target of operation, duration of follow-up, stimulation parameters, adverse events, and outcome measures were collected. RESULTS: Twenty eligible studies, assessing 42 patients with HD, were identified. The effect of globus pallidus internus (GPi) DBS on Unified Huntington's Disease Rating Scale (UHDRS) total score revealed in 10 studies an improvement of total score from 5.4 to 34.5%, and in 4 studies, an increase of motor score from 3.8 to 97.8%. Bilateral GPi-DBS was reported to be effective in reducing Chorea subscore in all studies, with a mean percentage reduction from 21.4 to 73.6%. CONCLUSIONS: HD patients with predominant choreic symptoms may be the best candidates for surgery, but the role of other clinical features and of disease progression should be elucidated. For this reason, there is a need for more reliable criteria that may guide the selection of HD patients suitable for DBS. Accordingly, further studies including functional outcomes as primary endpoints are needed.

Reactivation of COVID-19 in a neurosurgical patient with early neuropsychiatric presentation. Does seroconversion mean immunity?

BACKGROUND: In the aftermath of COVID-19 outbreak, there is a strong need to find strategies to monitor SARSCoV-2 transmission. While the application of screening techniques plays a major role to this end, there is evidence challenging the real significance of seroconversion. We reported a case of COVID-19 reactivation associated with a neurosurgical operation with early neuropsychiatric involvement presumably promoted by olfactory and gustatory impairment in the first infection. CASE DESCRIPTIO: A 57-year-old man was referred for a 2-month history of progressive development of imbalance, dizziness, and vomiting. Magnetic resonance imaging showed two bilateral hemispheric cerebellar lesions. In line with our triage protocol, the patient underwent a nasopharyngeal swab for RNA of SARS-CoV-2 detection, which resulted positive. Of note, the patient had reported in the previous month hyposmia and hypogeusia. After a period of 14 days, three new swabs were performed with negative results, leading the way to surgery. In the early post-operative period, the patient manifested acute onset of psychotic symptoms with hyperactive delirium, followed by fever and acute respiratory failure. A chest computed tomography revealed a specific pattern of ground-glass opacities in the lower lobes bilaterally, suggesting a viral pneumonia. Serological tests demonstrated the seroconversion and a new nasopharyngeal swab confirmed SARS-CoV-2 infection. CONCLUSION: Our report highlights the importance of comprehensive screening assessments in sensitive cases highly susceptible to COVID-19 recurrence.

Base-peak assessment of levodopa response and detection of fluctuating patients in Parkinson's disease.

OBJECTIVES: This study aims to evaluate the base-peak difference in levodopa response for detecting patients with motor fluctuations in Parkinson's disease (PD). METHODS: Two independent PD samples were evaluated at baseline and 2 h after the administration of the usual morning dose of levodopa using the Unified Parkinson's Disease Rating Scale part III (UPDRS-III). The presence of motor fluctuations was defined by the UPDRS-IV. We quantified the magnitude of motor variation as absolute (Δ) and percentage (Δ%) change in UPDRS-III scores. Optimal cut-offs for each index distinguishing patients with or without fluctuations were calculated on the exploratory population. The accuracy of the identified cut-offs was then verified in a testing population. RESULTS: In the exploratory population (N = 26), the optimal cut-off for detecting fluctuations was a Δ of 6 points and a Δ% of 18.4%. When we applied the identified thresholds to the testing population (N = 139), we found a sensitivity of 93.8% (95% CI: 89.7 to 97.8) and a specificity of 91.2% (95% CI: 86.5 to 95.9) for Δ, 83.3% (95% CI: 77.1 to 89.5) and 86.8% (95% CI: 81.2 to 92.4) for Δ%, respectively. CONCLUSIONS: The assessment of levodopa usual morning dose response through the base-peak evaluation represents an accurate method for detecting parkinsonian patients with motor fluctuations, and for defining the Minimal Important Difference (MID) in levodopa response suggesting the presence of motor fluctuations in PD patients demanding further therapeutic interventions.

Metabolomics markers in Neurology: current knowledge and future perspectives for therapeutic targeting.

INTRODUCTION: Metabolomics is an emerging approach providing new insights into the metabolic changes and underlying mechanisms involved in the pathogenesis of neurological disorders. AREAS COVERED: Here, the authors present an overview of the current knowledge of metabolic profiling (metabolomics) to provide critical insight on the role of biochemical markers and metabolic alterations in neurological diseases. EXPERT OPINION: Elucidation of characteristic metabolic alterations in neurological disorders is crucial for a better understanding of their pathogenesis, and for identifying potential biomarkers and drug targets. Nevertheless, discrepancies in diagnostic criteria, sample handling protocols, and analytical methods still affect the generalizability of current study results.

Voluntary Inhibitory Control of Chorea: A Case Series.

BACKGROUND: Volitional control of involuntary movements has so far been considered a hallmark of tic disorders. However, modulation of involuntary movements can also be observed in other hyperkinesias. CASES: Here, we present 6 patients with chorea able to suppress their involuntary movements, on demand. In 3 of them, surface electromyography was used to quantify degree of suppression and confirmed a reduction of muscle activity up to 68%, during volitional control. CONCLUSION: This observation represents a first step toward a description of a new clinical feature in choreic syndromes and an opportunity to redefine the role of volitional inhibition in hyperkinetic movement disorders.

Self-Injurious Behaviour in SCA17: A New Clinical Observation.

Background: Self-injurious behaviour has historically been associated with borderline personality disorder. Nevertheless, over recent years, it has been reported in numerous neurological syndromes, especially hyperkinesias. Case report: Two cases of SCA17 manifested self-injurious behaviour, namely repetitive scratching of the skin resulting in severe excoriations. In one of them, the abnormal behaviour was associated with the inability to resist the impulse to commit the act along with relief following the damage. Discussion: This is the first report describing self-injurious behaviour in SCA17, but the mechanisms underlying it are still not clear. Further studies are needed to clarify the pathophysiology of such manifestation in hyperkinetic syndromes.

Accuracy of MDS-UPDRS section IV for detecting motor fluctuations in Parkinson's disease.

BACKGROUND: In a precedent paper, we validated part IV of the Unified Parkinson's Disease Rating Scale (UPDRS) for detecting motor fluctuations in Parkinson's Disease (PD) patients using a 12-h Waking-Day Motor Assessment (WDMA) as gold standard, showing a high sensitivity (> 80%) and a lower specificity (< 45%). The aim of this study was to validate the Movement Disorder Society-UPDRS (MDS-UPDRS) part IV, especially items 4.3 and 4.5, using the same methodology. METHODS: PD patients attending the Movement Disorders Clinic at the University Hospital in Catania were consecutively enrolled in the study. A diurnal WDMA was performed to detect motor fluctuations. At each time interval, the motor impairment was evaluated using the motor section of the MDS-UPDRS. Presence or absence of motor fluctuations and the type of motor fluctuation were assessed by four blinded expert raters in movement disorders, by evaluating the graphical representations of the WDMA. We evaluated sensitivity and specificity together with 95% Confidence Interval (CI) of items 4.3 and 4.5, using WDMA as gold standard. RESULTS: We estimated for item 4.3 of the MDS-UPDRS a sensitivity of 74.3% (95% CI 56.7-87.5) and a specificity of 70.6% (95% CI 44-89.7), while for item 4.5, a sensitivity of 67.9% (95% CI 47.6-84.1) and a specificity of 66.7% (95% CI 44.7-84.4). CONCLUSIONS: The present showed a higher specificity level for MDS-UPDRS with respect to the UPDRS, while a slightly lower sensitivity mainly for predictable OFF.

Quantitative estimation of motor fluctuations in Parkinson's disease.

OBJECTIVES: To provide a quantitative estimation of motor fluctuations in PD through a 12-h Waking-day Motor Assessment (WDMA) and to develop new WDMA-based tools, the Motor Fluctuation Indices. METHODS: Two independent samples of PD patients (exploratory population N = 51, testing population N = 109) were examined. Patients underwent a WDMA using the Unified Parkinson's Disease Rating Scale (UPDRS) and were classified as either having or not having motor fluctuations. To quantify motor fluctuations, the Worsening Index (WI), the Mean Fluctuation Index (MFI) and the Coefficient of Variation (CV) were computed. The optimal cut-off for each index distinguishing patients with or without fluctuations was calculated on the exploratory population. Cut-offs' accuracy was then verified in the testing population. RESULTS: Optimal cut-off scores to differentiate stable patients from fluctuating ones were 8.3 for WI, 5 for MFI and 12.9 for CV. Sensitivity and a specificity were 91.2% (95%CI: 85.9 to 96.5) and 87.8% (95%CI: 81.7 to 93.9) for WI; 75% (95%CI: 66.9 to 83.1) and 90.2% (95%CI: 84.7 to 95.8) for MFI; 69.1% (95%CI: 60.4 to 77.8) and 95.1% (95%CI: 91.1 to 99.2) for CV. Patients with a larger magnitude of fluctuation had higher values for all three indices, whereas patients with multiple daily fluctuations presented only higher WI values. CONCLUSIONS: WDMA-derived Motor Fluctuation Indices may represent reliable tools for evaluating and quantifying the severity of motor fluctuations in PD patients. Even if WDMA is a time-consuming procedure, the detection of Motor Fluctuation Indices could be helpful in assessing therapeutic efficacy on motor fluctuations.

Willingness to pay for one-stop anesthesia in pediatric day surgery.

BACKGROUND: This study assesses the parents' Willingness To Pay (WTP) for One Stop Anesthesia (OSA). OSA is part of a free screening procedure that determines the timing of the anesthesiological assessment. In OSA-positive patients, the preoperative assessment is carried out on the same day as the surgery. The OSA allows patients who have to undergo surgery in a pediatric day surgery to avoid accessing the pre-admission clinic. METHOD: This is a descriptive cohort study. A sample of 106 parents were interviewed directly by means of a questionnaire. The questionnaire builds a hypothetical scenario where the interviewee has a chance to buy the OSA health service with the WTP. The WTP values are distributed in classes and are contingent to the market built in the questionnaire. The Chi Square and Cramer's V tests evaluate the WTP dependence on the parents' place of origin and occupation. RESULTS: The approximate average of the WTP classes is €87.21 per family. The Chi Square test relative to the WTP classes and the places of origin is statistically significant (p < 0.05). The Cramer's V test is 0.347 and points to a positive association between the two demographics. The Cramer's V test of the WTP classes and the types of job is 0.339 and indicates a positive association. CONCLUSION: Nearly 90% of pediatric patients who were screened for timing the preoperative assessment are true positives to OSA. This allows doing away with the pre-hospitalization, with definite advantages for the families. This screening is a health service that families would be hypothetically willing to pay.

Diagnostic accuracy of anesthesiology evaluation timing: the 'One-Stop Anesthesia' in pediatric day-surgery.

OBJECTIVE: Assessing timing efficacy of anesthetic evaluation in pediatric day-surgery by a diagnostic accuracy study. AIM: Lowering hospital visits in patients with negative medical history. BACKGROUND: Pediatric patients scheduled for day-surgery procedures can be categorized, according to their history, in two groups. One, the largest, includes healthy patients and the other includes those with medical conditions that necessitate further evaluation. MATERIALS AND METHODS: Clinical data are collected by the pediatric surgeons of our department and reviewed by an anesthetist who then selects the timing of anesthesiology evaluation, which will take place in the same day of the procedure (One-Stop Anesthesia), or some days before it, in a dedicated setting (Pre-Admission Clinic). In 2008, 332 children, older than 12 months, screened by that method, underwent surgical procedures in general anesthesia. RESULTS: Our data were examined using Bayesian Statistical Analysis. In the 'One-Stop Anesthesia' group, true positive were 290 (87.4%) and false positive 4 (1.2%). Of the 38 patients assessed by our Pre-Admission Clinic, true negative were 30 (9%) and false negative 8 (2.4%). Sensibility (97.3%), specificity (88.2%), positive predictive value (98.6%), negative predictive value (78.9%), diagnostic accuracy (96.4%), likelihood positive (8.3), and likelihood negative (0.03) were calculated. CONCLUSIONS: Timing the preoperative anesthesiologist's evaluation avoided 88% of hospital visits, usually to the Pre-Admission Clinic, and thus, it was cost effective, reducing direct and indirect costs of healthcare providers.