Degenerative Lumbar Spine Stenosis Consensus Conference: the Italian job. Recommendations of the Spinal Section of the Italian Society of Neurosurgery.

In the modern era evidence-based medicine, guidelines and recommendations represent a key-point of daily activity. The Spinal Section of the Italian Society of Neurosurgery introduced some recommendations regarding Degenerative Lumbar Spine Stenosis based on those of the Spine Committee of World Federation of Neurosurgical Societies, revising them on the basis of Italian common practice. In June 2019, a Committee of 21 spine surgeons met in Rome to validate the recommendations of the WFNS. Furthermore, they decided to review the ones that did not reach a consensus to create Italian Recommendations on Degenerative Lumbar Spine Stenosis. A literature review of the last ten years was performed and the statements were voted using the Delphi method. Forty-one statements were discussed, and 7 statements were voted again to reach a consensus with respect to those of the WFNS. A total of 40 statements reached a consensus, of which 36 reached a positive consensus and 4 a negative consensus, while no consensus was reached in 1 case. Conservative multimodal therapy, tailored on the patient, is a reasonable and effective first option choice for the treatment of LSS patients with tolerable moderate symptoms. Surgical treatment is reserved for symptomatic patients non-responding to conservative treatment or with neurological deficits. The best surgical technique to use depends on personal experience; modern MISS techniques are equivalent to open decompressive surgery with some advantages and higher cost-effectiveness. Fusion surgery and mobility preserving surgery only have a marginal role in the treatment of DLSS without instability.

Purely Meningeal Intracranial Relapse of Melanoma Brain Metastases After Surgical Resection and Immunotherapy as a Unique Disease Progression Pattern: Our Experience and Review of the Literature.

BACKGROUND: We present a case of 72-year-old man with a history of metastatic melanoma diagnosed in 2015 presenting a stable disease in treatment with dabrafenib. CASE DESCRIPTION: The patient had been surgically treated for a presumed intracranial parietooccipital metastasis. He presented 1 month later with a meningeal lesion associated with a subdural hematoma. A second surgical treatment confirmed the diagnosis of meningeal recurrence of metastatic melanoma. CONCLUSIONS: The most recent literature lacks studies defining the clinical phenomena of an early recurrence of intracranial melanoma with de novo involvement of dural compartment in patients in treatment with a target immunotherapy. The aim of this present study is to report a case of early recurrence of intracranial melanoma metastases with evidence of fast immunohistochemical and macroscopical mutation of pathologic elements, with an analysis of literature that shows the lack of well-described occurrences.

Intradural extramidullary dorsal melanocytoma in the adult: Case report and review of the literature.

Intradural Extramedullary Spinal Melanocytoma (IESM) is an extremely uncommon tumour arising from the spinal leptomeninges; both from a gross pathology and microscopic point of view it can mimick its malignant counterpart, the Melanoma. Such tumours are usually solitary, with a lower proliferating rate and without obvious SC invasion. Their common differential diagnoses include Spinal Schwannoma and Spinal Meningiomas since they share a significant amount of radiological similarities. It is a relatively benign condition which is, to date, with no more than 24 previously reported cases, yet widely unexplored and poorly understood. We report the detailed clinical history of a 60 years old individual suffering from IESM and, by means of a thorough Literature review, the most relevant features concerning the epidemiological issues, the clinical course, the radiological appearance, the surgical results and the typical gross and microscopic pathology of a cohort of previously reported cases of IESM are extensively discussed and systematically investigated through statistical analyses in order to add to the relevant Literature a dedicated work concerning this rare and enigmatic condition.

Real-Time Distal, Multifocal, Repeated Lenticulostriate Bleeding Points during Thrombectomy in a Patient with Acute Variable M1 Occlusion: A Case Report and a Literature Review.

BACKGROUND: Intracerebral hemorrhage can be classified as either primary or secondary to various conditions such as vascular anomalies or stroke. We present a case of real-time incident detected on digital subtraction angiography (DSA) during thrombectomy in a patient with acute variable M1 occlusion. MATERIALS AND METHODS: A comprehensive literature search of the PubMed and Scopus databases was conducted: this is the first real-time visualization using DSA of a basal ganglia hematoma formation secondary to distal multifocal bleeding points just before a thrombectomy in a patient with acute variable M1 occlusion. CONCLUSION: We suggest that the positions of the clot before and during the procedure be compared always.

Transpedicular Approach to Thoracic Disc Herniaton Guided by 3D Navigation System.

BACKGROUND: The choice of surgical approach for thoracic disc herniation should consider the location on the axial plane and the consistency of the herniated disc. Calcified midline disc herniations are difficult to remove with a transpedicular approach because of limitations due to blind spots; so they are usually treated via a transthoracic approach, although this entails a high risk of thoracopulmonary injuries. METHODS: In this work we present two cases of calcified midline thoracic disc herniations treated with a transpedicular approach, improved by using a three-dimensional (3D) neuronavigation system to verify the extent of removal on the blind side. RESULTS: Postoperative computed tomography (CT) scans demonstrated that this original technical innovation, in the two present cases, allowed us to reach the side opposite the disc herniation and to assess the extent of resection at the end of the procedure. CONCLUSIONS: The employment of a neuronavigation system in the transpedicular approach allowed safe and effective removal of calcified midline thoracic disc herniations. We did not observe any postoperative neurological worsening, onset of spinal instability, or other adverse events.

Successful subthalamic stimulation, but levodopa-induced dystonia, in a genetic Parkinson's disease.

Recently, it is under scrutiny the possibility to anticipate the stereotactic implantation of the subthalamic nucleus (STN) even in relatively mild Parkinson's disease (PD) patients with an unsatisfying response to drugs. In addition, it is debated whether levodopa (LD) and deep brain stimulation (DBS) are congruent or, instead, mutually exclusive. A 56-year-old LRRK2-positive PD patient, with 7 years of disease history, dominated by severe left resting tremor, was submitted to bilateral implantation of the subthalamic nucleus (STN). Before surgery, the combination of LD and dopamine agonists failed to handle tremor unless administered at doses, which induced undesirable adverse events. STN deep brain stimulation (DBS) abolished tremor but did not provide satisfying control of hypokinetic-rigid symptoms. The condition STIM-ON plus LD, albeit transiently beneficial, installed a painful dystonia developing slowly after 24-36 h. Only a chronic therapy combining rotigotine plus STN-DBS proved effective without side effects. This case report, based upon the surprising difference between the therapeutic response to the combination of LD and dopamine agonist (before surgery) and the combination of DBS and agonist after surgery, emphasizes how STIM and LD target different motor domains through mechanisms with differential plasticity and confirms the efficacy of STN-DBS in LRKK2 patients.

Reduced GABA Content in the Motor Thalamus during Effective Deep Brain Stimulation of the Subthalamic Nucleus.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN), in Parkinson's disease (PD) patients, is a well established therapeutic option, but its mechanisms of action are only partially known. In our previous study, the clinical transitions from OFF- to ON-state were not correlated with significant changes of GABA content inside GPi or substantia nigra reticulata. Here, biochemical effects of STN-DBS have been assessed in putamen (PUT), internal pallidus (GPi), and inside the antero-ventral thalamus (VA), the key station receiving pallidothalamic fibers. In 10 advanced PD patients undergoing surgery, microdialysis samples were collected before and during STN-DBS. cGMP, an index of glutamatergic transmission, was measured in GPi and PUT by radioimmunoassay, whereas GABA from VA was measured by HPLC. During clinically effective STN-DBS, we found a significant decrease in GABA extracellular concentrations in VA (-30%). Simultaneously, cGMP extracellular concentrations were enhanced in PUT (+200%) and GPi (+481%). These findings support a thalamic dis-inhibition, in turn re-establishing a more physiological corticostriatal transmission, as the source of motor improvement. They indirectly confirm the relevance of patterning (instead of mere changes of excitability) and suggest that a rigid interpretation of the standard model, at least when it indicates the hyperactive indirect pathway as key feature of hypokinetic signs, is unlikely to be correct. Finally, given the demonstration of a key role of VA in inducing clinical relief, locally administration of drugs modulating GABA transmission in thalamic nuclei could become an innovative therapeutic strategy.

Acute inactivation of the medial forebrain bundle imposes oscillations in the SNr: a challenge for the 6-OHDA model?

It has been recently shown that the substantia nigra pars reticulata (SNr) of 6-hydroxydopamine (6-OHDA)-lesioned rats, under urethane anaesthesia, manifests a prominent low frequency oscillation (LFO) of around 1Hz, synchronized with cortical slow wave activity (SWA). Nevertheless, it is poorly understood whether these electrophysiological alterations are correlated only with severe dopamine depletion or may also play a relevant pathogenetic role in the early stages of the dopamine denervation. Hence, here we recorded SNr single units and electrocorticogram (ECoG) in two models of dopamine denervation: (i) acute dopamine denervated rats, obtained by injection of tetrodotoxin (TTX), (ii) chronic dopamine depleted rats, 2 weeks after 6-OHDA lesioning. Both TTX and 6-OHDA were infused into the medial forebrain bundle (MFB). The acute TTX-mediated dopamine depletion caused a fast developing occurrence of a SNr/ECoG coherence, peaking between 0.48 and 1.22 Hz, parallel with a consistent decrease of firing rate (from 22.61 ± 7.04 to 15.35 ± 9.04 Hz) homolateraly to the infusion. Strikingly, this abnormal 1 Hz synchronization, TTX-mediated was qualitatively similar to the ECoG/SNr synchronization detectable in the 6-OHDA lesioned hemisphere (LH). In addition, TTX infusion in the un-lesioned hemispheres (UH) of 6-OHDA treated rats, produced ECoG/SNr synchronization qualitatively similar to that recordable in the LH. Hence, our data support the proposition that LFO, is tightly correlated to cortex, and represent a critical hallmark of a basal ganglia (BG) failure from the early stages of dopamine denervation.

Non-motor functions in parkinsonian patients implanted in the pedunculopontine nucleus: focus on sleep and cognitive domains.

Between 2005 and 2007, six patients affected by idiopathic Parkinson's disease (IPD) were submitted to the bilateral implantation (and subsequent deep brain stimulation - DBS) of the pedunculopontine nucleus (PPN) plus the subthalamic nucleus (STN). This review synthesizes the effects of PPN low-frequency stimulation on non-motor functions, focusing on patient sleep quality and cognitive performance. If not associated to STN-DBS, PPN-DBS promoted a modest amelioration of patient motor performance. However, during PPN-DBS, they experienced on the one hand a significant improvement in executive functions and working memory, on the other hand a beneficial change in sleep architecture. Overall, the limited sample hampers definite conclusions. Yet, although the PPN-DBS induced motor effects are quite disappointing (discouraging extended trials based upon the sole PPN implantation), the neuropsychological profile supports the contention by which in selected PD patients, with subtle cognitive deficits or vanished efficacy of previous implanted STN, PPN-DBS might still represent a reliable and compassionate option.

The pharmacological blockade of medial forebrain bundle induces an acute pathological synchronization of the cortico-subthalamic nucleus-globus pallidus pathway.

Pathological oscillations characterize the firing discharge of different basal ganglia (BG) stations in rat models of Parkinson's disease. Most recent literature focused on the prominence of the beta frequency band in awake rats. Yet, in 6-hydroxydopamine-lesioned animals, the firing discharge of the globus pallidus (GP) and the substantia nigra reticulata are in phase with urethane-induced slow wave cortical activity. The neuronal basis of this pathological synergy at low frequency is widely debated. In order to understand the role of substantia nigra pars compacta (SNc) signalling in the development of pathological synchronization, we performed a pharmacological inactivation of the medial forebrain bundle (MFB) through tetrodotoxin (TTX), which led to a dramatic, but reversible, reduction of the dopamine content in the striatum. This procedure caused a significant contralateral akinesia, detectable as soon as anaesthesia vanished, and lasting about 3-4 h. We sought to determine the electrophysiological counterpart of this transient Parkinsonian-like hypokinetic syndrome. Hence, we obtained the electrocorticogram (ECoG) and single unit recordings from GP and subthalamic nucleus (STN) in normal rats before and after the TTX injection in MFB. Intriguingly, the TTX-mediated inactivation of MFB induced a fast developing coherence between cortex and GP and a significant increase of the cortex/STN synchronization. The intra-GP iontophoretic delivery of haloperidol or the GABA(A) receptor antagonist bicuculline induced a short term cortex/GP synchronization. Strikingly, STN inactivation by local muscimol reversed both haloperidol- and TTX-mediated coherence between cortex and GP. Our data show that an abnormal cortical/BG synchronization, at low frequency, can be reproduced also without SNc neuronal loss and striatal cytoarchitectonic alterations. In addition, our results, which represent an acute and reversible Parkinsonism based upon impaired cable properties, seem compatible with the interpretation of acute changes of the functional interplay between cortex and the STN-GP pathway as a key factor mechanism underlying the fast deep brain stimulation-induced acute Off-On transitions.