Open thoracic cordotomy for intractable cancer pain: a how I do it.

BACKGROUND: Some cancers of the lower extremity involve nerves and plexuses and can produce extreme drug-resistant noceptive pain. In these cases, open thoracic cordotomy can be proposed. METHOD: This procedure involves disruption of the spinothalamic tract, which sustains nociceptive pathways. After placement in the prone position, selection of the side to be operated on (contralateral to the pain), and dura exposure, microsurgery is used to section the anterolateral spinal cord quadrant previously exposed by gently pulling on the dentate ligament. CONCLUSION: Open thoracic cordotomy is a moderate invasive, safe, and effective option for the management of drug-resistant unilateral lower extremity cancer pain in well-selected patients.

Intracranial aneurysms in pediatric population: a two-center audit.

OBJECTIVE: Intracranial aneurysms (IA) in children are rare, accounting for less than 5% of all IA. Due to their scarcity, the epidemiology is poorly understood and differs from adults in term of clinical presentation, size, location, and origin. Consequently, the treatment strategies are specific and cannot be only based on data from adult series. The aim of our study was to report the characteristics, management, and outcomes of children treated for IA in two university hospitals located in Normandy (France) over the last 17 years and to perform a literature review of this rare pathology. METHODS: This retrospective study included 18 consecutive children (< 18 years old) admitted with cerebral aneurysm treated in two neurosurgery departments in Normandy, from 2001 to 2018. Computerized tomography and cerebral angiography established the diagnosis. Both endovascular and surgical procedures were discussed in all cases. Data focused on clinical condition at admission, characteristics of the IA, choice of the treatment modalities, and complications. The outcome at follow-up is based on Glasgow outcomes scale (GOS) at 1 year. RESULTS: During the study period, 18 children (mean age: 12.6 years; sex ratio male/female: 2.3) were admitted with 21 IA. Aneurysms had a mean size of 13.6 mm with 4 giant aneurysms and were mostly located in the anterior circulation (16/21). Clinical presentations at onset were sudden symptoms related to a subarachnoid hemorrhage in 13 patients, headaches in 4 patients with giant aneurysm, and asymptomatic in one patient. Among the 13 patients with ruptured IA, 6 presented in poor preoperative condition (Hunt and Hess Grade ≥ 4). Treatment modalities consisted in embolization in 9 patients and surgery in 9 patients including 2 by-pass surgeries in fusiform aneurysms. Complications were similar in the two groups, but two cases of recanalization were observed in the endovascular group. At 1 year of follow-up, 14 children were in good condition (GOS Score > 4) and one died. Three children presented associated IA treated by the same technique as initial aneurysm. CONCLUSIONS: Pediatric aneurysm is a different pathology compared with adults, occurring more frequently in male population with a higher proportion of giant aneurysms and aneurysms located in the internal carotid bifurcation. The use of endovascular techniques has progressed in the last years, but surgery was proposed for half of our population.

General Anesthesia Inhibits the Activity of the "Glymphatic System".

INTRODUCTION: According to the "glymphatic system" hypothesis, brain waste clearance is mediated by a continuous replacement of the interstitial milieu by a bulk flow of cerebrospinal fluid (CSF). Previous reports suggested that this cerebral CSF circulation is only active during general anesthesia or sleep, an effect mediated by the dilatation of the extracellular space. Given the controversies regarding the plausibility of this phenomenon and the limitations of currently available methods to image the glymphatic system, we developed original whole-brain in vivo imaging methods to investigate the effects of general anesthesia on the brain CSF circulation. METHODS: We used magnetic resonance imaging (MRI) and near-infrared fluorescence imaging (NIRF) after injection of a paramagnetic contrast agent or a fluorescent dye in the cisterna magna, in order to investigate the impact of general anesthesia (isoflurane, ketamine or ketamine/xylazine) on the intracranial CSF circulation in mice. RESULTS:In vivo imaging allowed us to image CSF flow in awake and anesthetized mice and confirmed the existence of a brain-wide CSF circulation. Contrary to what was initially thought, we demonstrated that the parenchymal CSF circulation is mainly active during wakefulness and significantly impaired during general anesthesia. This effect was especially significant when high doses of anesthetic agent were used (3% isoflurane). These results were consistent across the different anesthesia regimens and imaging modalities. Moreover, we failed to detect a significant change in the brain extracellular water volume using diffusion weighted imaging in awake and anesthetized mice. CONCLUSION: The parenchymal diffusion of small molecular weight compounds from the CSF is active during wakefulness. General anesthesia has a negative impact on the intracranial CSF circulation, especially when using a high dose of anesthetic agent.

Modification of apparent intracerebral hematoma volume on T2∗-weighted images during normobaric oxygen therapy may contribute to false diagnosis.

It was previously reported that normobaric oxygen therapy (NBO) significantly affected T2∗-weighted imaging in a mouse model of intracerebral hemorrhage (ICH). However, it is unclear whether a similar phenomenon exists in large volume ICH as seen in human pathology. We investigated the effects of NBO on T2∗-weighted images in a pig model of ICH. Our data show that NBO makes disappear a peripheral crown of the hematoma, which in turn decreases the apparent volume of ICH by 18%. We hypothesized that this result could be translated to ICH in human, and subsequently could lead to inaccurate diagnostic.

Cerebrospinal fluid flow increases from newborn to adult stages.

Solute transport through the brain is of major importance for the clearance of toxic molecules and metabolites, and it plays key roles in the pathophysiology of the central nervous system. This solute transport notably depends on the cerebrospinal fluid (CSF) flow, which circulates in the subarachnoid spaces, the ventricles and the perivascular spaces. We hypothesized that the CSF flow may be different in the perinatal period compared to the adult period. Using in vivo magnetic resonance imaging (MRI) and near-infrared fluorescence imaging (NIRF), we assessed the dynamic of the CSF flow in rodents at different ages. By injecting a contrast agent into the CSF, we first used MRI to demonstrate that CSF flow gradually increases with age, with the adult pattern observed at P90. This observation was confirmed by NIRF, which revealed an increased CSF flow in P90 rats when compared with P4 rats not only at the surface of the brain but also deep in the brain structures. Lastly, we evaluated the exit routes of the CSF from the brain. We demonstrated that indocyanine green injected directly into the striatum spread throughout the parenchyma in adult rats, whereas it stayed at the injection point in P4 rats. Moreover, the ability of CSF to exit through the nasal mucosa was increased in the adult rodents. Our results provide evidence that the perinatal brain has nonoptimal CSF flow and exit and, thus, may have impaired clean-up capacity. © 2018 Wiley Periodicals, Inc. Develop Neurobiol, 2018.

Clipping Versus Coiling in the Management of Posterior Communicating Artery Aneurysms with Third Nerve Palsy: A Systematic Review and Meta-Analysis.

OBJECTIVE: To compare surgical clipping with endovascular coiling in terms of recovery from oculomotor nerve palsy (ONP) in the management of posterior communicating artery (PCoA) aneurysms causing third nerve palsy. METHODS: We conducted a systematic review of the literature and meta-analysis. RESULTS: The meta-analysis included 11 relevant studies involving 384 patients with third nerve palsy caused by PCoA aneurysms at baseline, of whom 257 (67.0%) were treated by clipping and 127 were treated by coiling (33.0%). Pooled odds ratios of the impact of clipping or coiling on complete ONP recovery, lack of ONP recovery, and procedure-related death were calculated. The overall complete ONP recovery rate was 42.5% in the coiling group compared with 83.6% in the clipping group. The increase in complete ONP recovery in the clipping group corresponds to an overall pooled Mantel-Haenszel odds ratio of 4.44 (95% confidence interval = 1.66-11.84). Subgroup analysis revealed a clear benefit of clipping over coiling in patients with ruptured aneurysms, but not in patients with unruptured aneurysms. No procedure-related deaths were reported by any of the 11 studies. CONCLUSIONS: Surgical clipping of PCoA aneurysms causing third nerve palsy achieves better ONP recovery than endovascular coiling; this could be particularly true in the case of ruptured aneurysms. In view of the purely observational data, statements about this effect should be made with great caution. A randomized trial would better address the therapeutic dilemma, but pending the results of such a trial, we recommend treating PCoA aneurysms causing ONP with surgery.