Neurosurgical untethering with or without syrinx drainage results in high patient satisfaction and favorable clinical outcome in post-traumatic myelopathy patients

Study design: Retrospective data collection and patient-reported outcome measures. Objectives: To investigate surgical outcome, complications, and patient satisfaction in patients with chronic SCI and symptomatic post-traumatic progressive myelopathy (PPM) who underwent neurosurgical untethering and/or spinal cord cyst drainage with the aim of preventing further neurological deterioration. Setting: Single-center study at an academic neurosurgery department. Methods: All SCI patients who underwent neurosurgery between 1996 and 2013 were retrospectively included. All medical charts and the treating surgeon’s operative reports were reviewed to identify surgical indications, surgical technique, and post-operative complications. A questionnaire and an EQ-5D-instrument were used to assess patient's self-described health status and satisfaction at long-term follow-up. Results: Fifty-two patients (43 men, 9 women) were identified, of whom five were dead and one was lost to follow-up. Main indications for surgery were pain (54%), motor (37%), or sensory (8%) impairment, and spasticity (2.0%). Overall complications were rare (8%). At follow-up, the subjectively perceived outcome was improved in 24 and remained unchanged in 21 patients. Thus, the surgical aim was met in 87% of patients. Of the 46 eligible patients, 38 responded to the questionnaire of whom 65% were satisfied with the surgical results. Patients with cervical lesions were more satisfied with the surgical treatment than patients with thoracic/thoracolumbar lesions (p = 0.05). Conclusions: Neurosurgical untethering and/or cyst drainage in chronic SCI patients and PPM resulted in a high degree of patient satisfaction, particularly in cervical SCI patients with minimal complications

mGluR5 antagonism inhibits cocaine reinforcement and relapse by elevation of extracellular glutamate in the nucleus accumbens via a CB1 receptor mechanism

Abstract Metabotropic glutamate receptor 5 (mGluR5) antagonism inhibits cocaine self-administration and reinstatement of drug-seeking behavior. However, the cellular and molecular mechanisms underlying this action are poorly understood. Here we report a presynaptic glutamate/cannabinoid mechanism that may underlie this action. Systemic or intra-nucleus accumbens (NAc) administration of the mGluR5 antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) dose-dependently reduced cocaine (and sucrose) self-administration and cocaine-induced reinstatement of drug-seeking behavior. The reduction in cocaine-taking and cocaine-seeking was associated with a reduction in cocaine-enhanced extracellular glutamate, but not cocaine-enhanced extracellular dopamine (DA) in the NAc. MPEP alone, when administered systemically or locally into the NAc, elevated extracellular glutamate, but not DA. Similarly, the cannabinoid CB1 receptor antagonist, rimonabant, elevated NAc glutamate, not DA. mGluR5s were found mainly in striatal medium-spiny neurons, not in astrocytes, and MPEP-enhanced extracellular glutamate was blocked by a NAc CB1 receptor antagonist or N-type Ca++ channel blocker, suggesting that a retrograde endocannabinoid-signaling mechanism underlies MPEP-induced glutamate release. This interpretation was further supported by our findings that genetic deletion of CB1 receptors in CB1-knockout mice blocked both MPEP-enhanced extracellular glutamate and MPEP-induced reductions in cocaine self-administration. Together, these results indicate that the therapeutic anti-cocaine effects of mGluR5 antagonists are mediated by elevation of extracellular glutamate in the NAc via an endocannabinoid-CB1 receptor disinhibition mechanism