Drezotomía en el tratamiento del dolor por desaferentización: revisión de resultados y análisis de factores predictores de éxito

Background and objectivesThe treatment of deafferentation pain by spinal DREZotomy is a proven therapeutic option in the literature. In recent years, use of DREZotomy has been relegated to second place due to the emergence of neuromodulation therapies. The objectives of this study are to demonstrate that DREZotomy continues to be an effective and safe treatment and to analyse predictive factors for success.Patients and methodsA retrospective study was conducted of all patients treated in our department with spinal DREZotomy from 1998 to 2018. Bulbar DREZotomy procedures were excluded. A visual analogue scale (VAS) and the reduction of routine medication were used as outcome variables. Demographic, clinical and operative variables were analysed as predictive factors for success.ResultsA total of 27 patients (51.9% female) with a mean age of 53.7 years underwent DREZotomy. The main cause of pain was brachial plexus injury (BPI) (55.6%) followed by neoplasms (18.5%). The mean time of pain evolution was 8.4 years with a mean intensity of 8.7 according to the VAS, even though 63% of the patients had previously received neurostimulation therapy. Favourable outcome (≥ 50% pain reduction in the VAS) was observed in 77.8% of patients during the postoperative period and remained in 59.3% of patients after 22 months average follow-up (mean reduction of 4.9 points). This allowed for a reduction in routine analgesic treatment in 70.4% of them. DREZotomy in BPI-related pain presented a significantly higher success rate (93%) than the other pathologies (41.7%) (p = .001). No association was observed between outcome and age, gender, DREZ technique, duration of pain or previous neurostimulation therapies. There were six neurological complications, four post-operative transient neurological deficits and two permanent deficits.ConclusionDorsal root entry zone surgery is effective and safe for treating patients with deafferentation pain, especially after brachial plexus injury. It can be considered an alternative treatment after failed neurostimulation techniques for pain control. However, its indication should be considered as the first therapeutic option after medical therapy failure due to its good long-term results.     

Dorsal Root Ganglion Stimulation for the Management of Intractable Painful Polyneuropathy: A Prospective Pilot Study

Objectives: Dorsal root ganglion stimulation (DRGS) is a promising neurostimulation modality in the treatment of painful polyneuropathy. The aim of this prospective pilot study was to investigate the effect of DRGS on pain intensity in patients with intractable painful polyneuropathy.Materials and Methods: Nine patients with chronic, intractable painful polyneuropathy in the lower limbs were recruited. In each subject, between two and four DRGS leads were placed at the level of the L5 and S1 dorsal root ganglion. If trial stimulation was successful, a definitive implantable pulse generator (IPG) was implanted. Pain intensity was scored using an 11-point numeric rating scale (NRS) and reported as median and interquartile range (IQR), and compared to baseline values using the Wilcoxon signed-rank test. Additionally, patients’ global impression of change (PGIC), pain extent, presence of neuropathic pain, physical functioning, quality of life, and mood were assessed.Results: Eight out of nine patients had a successful trial phase, of which seven received an IPG. Daytime pain decreased from a median (IQR) NRS score of 7.0 (5.9–8.3) to 2.0 (1.0–3.5) and 3.0 (1.6–4.9) in the first week and at six months after implantation, respectively. Similar effects were observed for night time and peak pain scores.Conclusions: The results of this study suggest that DRGS significantly reduces both pain intensity and PGIC in patients with intractable painful polyneuropathy in the lower extremities. Large-scale clinical trials are needed to prove the efficacy of DRGS in intractable painful polyneuropathy.     

Motor dysfunction in mild cognitive impairment as tested by kinematic analysis and transcranial magnetic stimulation

ObjectivePrevious studies have demonstrated voluntary movement alterations as well as motor cortex excitability and plasticity changes in patients with mild cognitive impairment (MCI). To investigate the pathophysiology of movement abnormalities in MCI, we tested possible relationships between movement abnormalities and primary motor cortex alterations in patients.MethodsFourteen amnestic MCI (aMCI) patients and 16 healthy controls were studied. Cognitive assessment was performed using clinical scales. Finger tapping was recorded by a motion analysis system. Transcranial magnetic stimulation was used to test the input/output curve of motor evoked potentials, intracortical inhibition, and short-latency afferent inhibition. Primary motor cortex plasticity was probed by theta burst stimulation. We investigated correlations between movement abnormalities, clinical scores, and cortical neurophysiological parameters.ResultsMCI patients showed less rhythmic movement but no other movement abnormalities. Cortical excitability measures were normal in patients, whereas plasticity was reduced. Movement rhythm abnormalities correlated with frontal dysfunction scores.ConclusionOur study in MCI patients demonstrated abnormal voluntary movement and plasticity changes, with no correlation between the two. Altered rhythm correlated with frontal dysfunction.SignificanceOur results contribute to the understanding of pathophysiological mechanisms of motor impairment in MCI.     

Comparison of quantitative susceptibility mapping methods on evaluating radiation-induced cerebral microbleeds and basal ganglia at 3T and 7T

Quantitative susceptibility mapping (QSM) has the potential for being a biomarker for various diseases because of its ability to measure tissue susceptibility related to iron deposition, myelin, and hemorrhage from the phase signal of a T₂*-weighted MRI. Despite its promise as a quantitative marker, QSM is faced with many challenges, including its dependence on preprocessing of the raw phase data, the relatively weak tissue signal, and the inherently ill posed relationship between the magnetic dipole and measured phase. The goal of this study was to evaluate the effects of background field removal and dipole inversion algorithms on noise characteristics, image uniformity, and structural contrast for cerebral microbleed (CMB) quantification at both 3T and 7T. We selected four widely used background phase removal and five dipole field inversion algorithms for QSM and applied them to volunteers and patients with CMBs, who were scanned at two different field strengths, with ground truth QSM reference calculated using multiple orientation scans. 7T MRI provided QSM images with lower noise than did 3T MRI. QSIP and VSHARP + iLSQR achieved the highest white matter homogeneity and vein contrast, with QSIP also providing the highest CMB contrast. Compared with ground truth COSMOS QSM images, overall good correlations between susceptibility values of dipole inversion algorithms and the COSMOS reference were observed in basal ganglia regions, with VSHARP + iLSQR achieving the susceptibility values most similar to COSMOS across all regions. This study can provide guidance for selecting the most appropriate QSM processing pipeline based on the application of interest and scanner field strength.     

氢氧化钙糊剂与根管内感染控制

感染控制对根管治疗的成功至关重要。尽管随着器械及设备的进步，对根管的清理及成形取得了很大的进展；然而，由于根管系统解剖结构错综复杂，使得获取清洁根管面临各种问题。例如：机械预备的宽度有限，不能彻底清理感染牙本质；冲洗技术的运用虽然可以去除根管器械预备后形成的玷污层，但对细菌内毒素的清除还是难以达到理想的效果，而残留的微生物、毒素等若得不到清除可能会在根尖周组织形成持续感染。因此，除外机械预备和冲洗，根管封药也是感染根管治疗过程中的重要步骤。氢氧化钙糊剂以其高效的抗菌作用在临床得到广泛使用。文章将对根管封药的必要性、氢氧化钙的作用机制及临床应用做一介绍。     

Electrophysiological differences between upper and lower limb movements in the human subthalamic nucleus

ObjectiveFunctional processes in the brain are segregated in both the spatial and spectral domain. Motivated by findings reported at the cortical level in healthy participants we test the hypothesis in the basal ganglia of Parkinson’s disease patients that lower frequency beta band activity relates to motor circuits associated with the upper limb and higher beta frequencies with lower limb movements.MethodsWe recorded local field potentials (LFPs) from the subthalamic nucleus using segmented “directional” DBS leads, during which patients performed repetitive upper and lower limb movements. Movement-related spectral changes in the beta and gamma frequency-ranges and their spatial distributions were compared between limbs.ResultsWe found that the beta desynchronization during leg movements is characterised by a strikingly greater involvement of higher beta frequencies (24–31 Hz), regardless of whether this was contralateral or ipsilateral to the limb moved. The spatial distribution of limb-specific movement-related changes was evident at higher gamma frequencies.ConclusionLimb processing in the basal ganglia is differentially organised in the spectral and spatial domain and can be captured by directional DBS leads.SignificanceThese findings may help to refine the use of the subthalamic LFPs as a control signal for adaptive DBS and neuroprosthetic devices.