Cerebrospinal Fluid Replacement Research Articles

Clinical Analysis of Poor Outcomes After Surgery for Aneurysmal Subarachnoid Hemorrhage in Guizhou, China

To investigate poor outcomes of aneurysmal subarachnoid hemorrhage (aSAH) and compare the clinicodemographic characteristics, imaging features, intervention strategies, laboratory tests, and complications of patients with good and poor outcomes to identify potential risk factors. We retrospectively analyzed patients with aSAH who underwent surgery in Guizhou, China, between June 1, 2014, and September 1, 2022. The Glasgow Outcome Scale was used to evaluate outcomes at discharge, with scores of 1-3 and 4-5 considered poor and good, respectively. Clinicodemographic characteristics, imaging features, intervention strategies, laboratory tests, and complications were compared between patients with good and poor outcomes. Multivariate analysis was used to determine independent risk factors for poor outcomes. The poor outcome rate of each ethnic group was compared. Of 1169 patients, 348 were ethnic minorities, 134 underwent microsurgical clipping, and 406 had poor outcomes at discharge. Patients with poor outcomes were older, represented fewer ethnic minorities, had a history of comorbidities, experienced more complications, and underwent microsurgical clipping. The top 3 types of aneurysms were anterior, posterior communicating, and middle cerebral artery aneurysms. Outcomes at discharge varied according to ethnic group. Han patients had worse outcomes. Age, loss of consciousness at onset, systolic blood pressure on admission, Hunt-Hess grade 4-5 on admission, epileptic seizures, modified Fisher grade 3-4, microsurgical clipping, size of the ruptured aneurysm, and cerebrospinal fluid replacement were independent risk factors for aSAH outcomes.

Cerebrospinal fluid replacement solutions promote neuroglia migratory behaviors and spinal explant outgrowth in microfluidic culture.

Disorders of the nervous system (NS) impact millions of adults, worldwide, as a consequence of traumatic injury, genetic illness, or chronic health conditions. Contemporary studies have begun to incorporate neuroglia into emerging NS therapies to harness the regenerative potential of glial-mediated synapses in the brain and spinal cord. However, the role of cerebrospinal fluid (CSF) that surrounds neuroglia and interfaces with their associated synapses remains only partially explored. The flow of CSF within subarachnoid spaces (SAS) circulates essential polypeptides, metabolites, and growth factors that directly impact neural response and recovery via signaling with healthy glia. Despite the availability of artificial CSF solutions used in neurosurgery and NS treatments, tissue engineering projects continue to use cell culture media, such as Neurobasal (NB) and Dulbecco's Modified Eagle Medium (DMEM), for development and characterization of many transplantable cells, matrixes, and integrated cellular systems. The current study examined in vitro behaviors of glial Schwann cells (ShC) and spinal cord explants (SCE) within a CSF replacement solution, Elliott's B Solution (EBS), used widely in the treatment of NS disorders. Our tests used EBS to create defined chemical microenvironments of extracellular factors within a glial line (gLL) microfluidic device, previously described by our group. The gLL is comparable in scale to the in vivo SAS that envelopes endogenous CSF and enables molecular transport via mechanisms of convective diffusion. Our results illustrate that EBS solutions facilitate ShC survival, morphology, and proliferation similar to those measured in traditional DMEM, and additionally support glial chemotactic behaviors in response to brain-derived growth factor (BDNF). Our data indicates that ShC undergo significant chemotaxis toward high and low concentration gradients of BDNF with statistical differences between gradients formed within diluents of EBS and DMEM solutions. Moreover, SCE cultured with EBS solutions facilitated measurement of neurite explant extension commensurate with reported in vivo measurements. This data highlights the translational significance and advantages of incorporating CSF replacement fluids to interrogate cellular behaviors and advance regenerative NS therapies.

A validated LC-MS/MS method for the simultaneous quantification of the novel combination antibiotic, ceftolozane-tazobactam, in plasma (total and unbound), CSF, urine and renal replacement therapy effluent: application to pilot pharmacokinetic studies.

Novel treatment options for some carbapenem-resistant Gram-negative pathogens have been identified by the World Health Organization as being of the highest priority. Ceftolozane-tazobactam is a novel cephalosporin-beta-lactamase inhibitor combination antibiotic with potent bactericidal activity against the most difficult-to-treat multi-drug resistant and extensively drug resistant Gram-negative pathogens. This study aimed to develop and validate a liquid chromatography- tandem mass spectrometry method for the simultaneous quantification of ceftolozane and tazobactam in plasma (total and unbound), renal replacement therapy effluent (RRTE), cerebrospinal fluid (CSF) and urine. Analytes were separated using mixed-mode chromatography with an intrinsically base-deactivated C18 column and a gradient mobile phase consisting of 0.1% formic acid, 10mM ammonium formate and acetonitrile. The analytes and internal standards were detected using rapid ionisation switching between positive and negative modes with simultaneous selected reaction monitoring. A quadratic calibration was obtained for plasma (total and unbound), RRTE and CSF over the concentration range of 1-200mg/L for ceftolozane and 0.5-100mg/L for tazobactam, and for urine the concentration range of 10-2,000mg/L for ceftolozane and 5-1,000mg/L for tazobactam. For both ceftolozane and tazobactam, validation testing for matrix effects, precision and accuracy, specificity and stability were all within the acceptance criteria of ±15%. This methodology was successfully applied to one pilot pharmacokinetic study in infected critically ill patients, including patients receiving renal replacement therapy, and one case study of a patient with ventriculitis, where all patients received ceftolozane-tazobactam.

Surgical Treatment of Tensile Effusion in Postoperative Cavity after Glioma Resection

Objectives: To explore the clinical surgical methods for the treatment of tensile effusion in postoperative cavity after glioma resection. Methods: Clinical data of 26 cases of tensile effusion in postoperative cavity after glioma resection were analyzed retrospectively. All 26 patients underwent surgical treatment, including 16 cases who underwent puncture and drainage (P&D), and 10 cases who underwent craniotomy decompression (CD). Among the cases of P&D, postoperative cavity in 7 cases were punctured through the burr hole for creating the skull flap for intraoperative resection of glioma, and postoperative cavities in 9 cases were punctured through a burr hole for the dura mater suspended under the skull flap. Glasgow Coma Scale (GCS) was used to evaluate the consciousness status of the two groups of patients before and after surgery. Moreover, time of operation, intraoperative blood loss, postoperative hospital duration, and postoperative complications were also adopted for evaluation of the merits of the two methods for treatment of tensile effusion in postoperative cavity after glioma resection. Results: The consciousness of the patients in both groups improved within 24 hours after the operation, and there were no death cases. In the P&D group, the GCS score within 24 hours after surgery was (14.38±0.20), the time of operation time was (7.81±0.64) mins, intraoperative blood loss was (6.25±0.56) ml, and postoperative hospital duration was (6.69±0.54) days. There were 3 cases with postoperative complications (1 case of puncture tract hemorrhage, 1 case of subdural hematoma and 1 case of intracranial infection) in the P&D group. All of the puncture tract hemorrhage and subdural hematoma did not require surgical treatment, and the intracranial infection was cured after antibiotic treatment and lumbar puncture for cerebrospinal fluid replacement. In the CD group, the GCS score within 24 hours after surgery was (13.70±0.21), the time of operation was (124.10±8.96) mins, intraoperative blood loss was (260±30.55) ml, and postoperative hospital duration was (11.30±0.60) days. There were 2 cases with postoperative complications (both of them were with subdural hematoma), none of which required surgical treatment. The GCS score, time of operation, intraoperative blood loss and postoperative hospital duration in the P&D group were better than those in the CD group (P < 0.05). There was no significant difference in the incidence of postoperative complications between the two groups (P >0.05). Conclusion: The P&D and CD for tensile effusion in postoperative cavity after glioma resection can both achieve ideal results, but P&D in line with the concept of micro-invasive neurosurgery was better than CD in terms of postoperative GCS score within 24 hours, duration of operative, intraoperative blood loss, and postoperative hospital duration.

Mechanical Dilution of Beta-amyloid Peptide and Phosphorylated Tau Protein in Alzheimer's Disease: Too Simple to be True?

The neuropathology of Alzheimer's disease (AD) is characterized by the widespread accumulation of neuritic plaques and neurofibrillary tangles composed of deposits of beta-amyloid peptide (Aβ) and abnormally phosphorylated tau protein (phospho-tau) respectively. Considerable effort has been expended to identify methods to retard the deposition of these proteins or to enhance their clearance. It is strikingly surprising that until now, very few researchers have attempted to remove these proteins using mechanical procedures.In this article, we start by showing the rationale of mechanical dilution of cerebrospinal fluid (CSF) as a therapeutic approach in AD. Then, we present models of implantable systems allowing mechanical dilution of CSF by means of CSF replacement and CSF filtration (liquorpheresis). We conclude that even though this approach seems simplistic, it is feasible and deserves exploration.

Implantable Systems for Continuous Liquorpheresis and CSF Replacement.

Liquorpheresis (cerebrospinal fluid filtration) comprises a therapeutical approach that has been proposed to treat several neurological conditions where antibodies, inflammatory mediators, or abnormal peptides are the cause or play an important role in the pathogenesis of the disease. Continuous or intermittent cerebrospinal fluid (CSF) replacement may be an alternative approach not explored thus far.Here, we review previous experiences in the use of liquorpheresis in autoimmune and degenerative neurological diseases. Then we describe previous technical reports and provide some new innovations in order to design bidirectional CSF shunting systems that can be complemented either with a deposit of artificial CSF or with a filter of CSF, allowing CSF replacement or liquorpheresis respectively. Both options would lead to mechanical dilution of the patient’s CSF.

Oxygenation of the cerebrospinal fluid with artificial cerebrospinal fluid can ameliorate a spinal cord ischemic injury in a rabbit model

ObjectiveWe evaluated the effect of cerebrospinal fluid oxygenation for the prevention of spinal cord ischemic injury after infrarenal aortic occlusion in a rabbit model. MethodsTwenty white Japanese rabbits were categorized into the following 4 groups (5 in each): group S (sham), balloon catheter insertion on to the aorta; group C (control), spinal cord ischemic injury by infrarenal abdominal aortic balloon occlusion for 15 minutes; group N (nonoxygenated), spinal cord ischemic injury with cerebrospinal fluid replacement by nonoxygenated artificial cerebrospinal fluid; and group O (oxygenated), spinal cord ischemic injury with cerebrospinal fluid replacement by nanobubble-oxygenated artificial cerebrospinal fluid. The changes in cerebrospinal fluid partial pressure of oxygen during the peri-ischemic period, modified Tarlov score, and histopathology of the spinal cord 48 hours after aortic maneuvers were evaluated. ResultsCerebrospinal fluid partial pressure of oxygen significantly increased in group O compared with group N after cerebrospinal fluid replacement (254.5 ± 54.8 mm Hg vs 136.1 ± 43.5 mm Hg, P = .02). After 15 minutes of spinal cord ischemic injury, cerebrospinal fluid partial pressure of oxygen in group C decreased to 65.8 ± 18.6 mm Hg compared with baseline (148.8 ± 20.6 mm Hg, P < .01), whereas cerebrospinal fluid partial pressure of oxygen in group O was maintained at remarkably high levels after spinal cord ischemic injury (291.9 ± 51.8 mm Hg), which was associated with improved neurologic function, with 20% of spinal cord ischemic injury having a Tarlov score less than 5 compared with 100% of spinal cord ischemic injury in group C. Preservation of anterior horn neurons in groups N and O was confirmed by histopathologic analysis with significant reduction of degenerated neurons compared with group C. ConclusionsCerebrospinal fluid oxygenation with artificial cerebrospinal fluid can exert a protective effect against spinal cord ischemic injury in rabbits.

Massive Cerebrospinal Fluid Replacement Reduces Delayed Cerebral Vasospasm After Embolization of Aneurysmal Subarachnoid Hemorrhage.

BackgroundDelayed cerebral vasospasm (DCVS) following aneurismal subarachnoid hemorrhage (SAH) is a leading cause of poor prognosis and death in SAH patients. Effective management to reduce DCVS is needed. A prospective controlled trial was conducted to determine if massive cerebrospinal fluid (CSF) replacement (CR) could reduce DCVS occurrence and improve the clinical outcome after aneurysmal SAH treated with endovascular coiling.Material/MethodsPatients treated with endovascular coiling after aneurysmal SAH were randomly divided into a control group receiving regular therapy alone (C group, n=42) and a CSF replacement group receiving an additional massive CSF replacement with saline (CR group, n=45). CSF examination, head CT, DCVS occurrence, cerebral infarction incidence, Glasgow Outcome Scale prognostic score, and 1-month mortality were recorded.ResultsThe occurrence of DCVS was 30.9% in the C group and 4.4% in the CR group (P<0.005). The cerebral infarction incidences in the C and CR groups were 19.0% and 2.2% (P<0.05), respectively, 1 month after the treatments. Mortality was not significantly different between the 2 groups during the follow-up period.ConclusionsMassive CR after embolization surgery for aneurysmal SAH can significantly reduce DCVS occurrence and effectively improve the outcomes.

Analysis on clinical curative effect of cerebrospinal fluid replacement therapy on the subarachnoid hemorrhage(SAH)patients with intracranial aneurysm embolization and nursing countermeasures

Objective To observe the effect of clinical curative effect of cerebrospinal fluid replacement therapy on the subarachnoid hemorrhage(SAH)patients with intracranial aneurysm embolization and nursing countermeasures. Methods The data of inpatients diagnosed of SAH were collected in the Second Hospital of Dalian Medical University from January 2008 to March 2012.102 cases of subarachnoid hemorrhage patients with intracranial aneurysm embolization were divided into two groups:cerebrospinal fluid replacement group(n=50)and the control group(n=52). Results In cerebrospinal fluid replacement group, the complications such as headache, stiff neck, hydrocephalus and cerebral vasospasm, the average hospitalization days were less than those in the control group(P< 0.05).The curative effect in the treatment group was better than that in control group. Conclusions Early cerebrospinal fluid replacement after intracranial aneurysm embolization in SAH patients can improve clinical symptoms, reduce the incidence of complications and shorten the average hospitalization days with meticulous care, improve the cure rate and quality of life, the cerebrospinal fluid replacement is worthy of clinical application. Key words: Cerebrospinal fluid replacement; Intracranial aneurysm embolization; Complication; Nursing

Peri-operative period nursing intervention on cerebrospinal fluid replacement for spontaneous subarachnoid hemorrhage

Objective To explore the clinical efficacy of nursing intervention on patients with spontaneous subarachnoid hemorrhage undergoing cerebrospinal fluid replacement.Methods 87 patients hospitalized into our hospital were randomly divided into experimental group and control group.The experimental group were given nursing intervention.Results The prognosis was better and the complication incidences was lower in experimental group than in control group significantly.Conclusion Carrying nursing intervention on patients with spontaneous subarachnoid hemorrhage undergoing cerebrospinal fluid replacement can make their prognosis better. Key words: Nursing intervention; Peri-operation; Cerebrospinal fluid replacement

Deep Brain Stimulation Shape and Surface Characteristics: Electrical and Mechanical Design Goals

O ne of the many risks associated with deep brain stimulation (3, 14) is the possibility of lead migration. Although typically this is defined as a large shift in lectrode position from the original placement (i.e., as identified y a change from immediate fluoroscopy to later imaging), there ould also be a more subtle shift in position due to normal brain ovement within the skull as a result of body posture and brain ulsation, replacement of cerebrospinal fluid postoperatively (i.e., s the air that enters during the procedure is later slowly emoved), or pathologically, such as with development of subural fluid or hematoma (6). The Parittotokkaporn et al. article ntroduces the concept of “microtexturing” the electrode to revent small scale shifts, with small “barbs” microfabricated on he surface of the semiconductor electrode so that the electrode s more stable within the brain over time. It is not clear whether echanically this would prevent large postoperative shifts in lectrode position (e.g., due to tugging or pulling while tunneling), ut the force required to displace or pull out the electrode ncreased significantly in the study, both within the brain as well s particularly when the burr hole cover was modified, when the lot for the electrode exit was microtextured. It is not clear hether this type of surface treatment could be performed on xisting materials (i.e., the Pt/Ir metal used for deep brain timulation [DBS] electrodes), but this type of microtexturing ertainly could be added to the exit slot on various forms of burr ole covers to prevent movement of the DBS electrode within he cover itself. Possible deleterious side effects of the microexturing of the DBS electrode itself include increased damage to he brain when purposefully retrieving the electrode, as opposed o the current, smooth DBS electrode, which typically pulls out ery easily when needed, and causes minor brain damage (13).

Application of low lateral drainage of bilateral alternating and turokinaseinstillation in treatment of spontaneous intraventricular hemorrhage

Objective To evaluate the clinical value of combined treatment for spontaneous intraventricular hemorrhage. Methods 26 patients with spontaneous intraventricular hemorrhage were conducted on the whole turn of low lateral drainage of bilateral urokinase infusion therapy, supplemented by lumbar puncture cerebrospinal fluid replacement. Results The total effective rate was 84.62% ,mortality rate was 15. 38%. Conclusion Bilateral lateral drainage of alternating low urokinase infusion,supplemented by lumbar puncture cerebrospinal fluid replacement was effective in treatment of spontaneous intraventricular hemorrhage. It could reduce mortality in patients with intraventricular hemorrhage and increase the patients' prognosis. Key words: Cerebral hemorrhage; Drainage; Urokinase; Cerebrospinal fluid replacement

Electrophysiology of papillary muscle in SAH: changes and N-acetylcysteine protection

Although subarachnoid hemorrhage (SAH) serves as a good model to study heart-brain interactions, neither the changes on the single ventricular action potential (SVAP) and contraction nor the effects of possible cardioprotective agents have been investigated. A total of 18 male rabbits were used for the three experimental groups. SAH was induced by replacing the cerebrospinal fluid (CSF) with fresh autologous blood at the ratio of 1 mL to the 1-kg body mass (N = 6). In the control (CON; N = 6) group, the CSF was replaced with serum physiologic at the same ratio. The treated SAH group (SAH+NAC) received daily intraperitoneal N-acetylcysteine (NAC; 150 mg/kg for 3 days) starting from just before SAH was induced by CSF replacement. On the fourth day, animals were examined for the single action potential and contraction recordings from the left ventricular papillary muscle. At the end of 3 days, the overshoot decreased together with increased time to reach the peak potential. Additionally, the resting membrane potential was depressed and repolarization was slowed during SVAPs. On the other hand, peak tension depressed and time to peak increased. NAC treatment, which protects infarction in the brain, prevented these pathological changes in the cardiac muscle. SAH-induced cardiac changes can be attributed to adenosine triphosphate depletion through mitochondrial dysfunction. Pretreatment of NAC to SAH on the other hand had a positive effect on these cardiac changes. But the exact mechanism by which NAC treatment protects the cardiac muscle needs further investigation.

Research in effect of cerebrospinal fluid replacement in treatment of subarachnoid hemorrhage and its nursing countermeasures

Objectives To investigate the effect of cerebrespinal fluid replacement using three- way pipe on subarachnoid hemorrhage and the nursing points were summarized. Methods 80 subarachnoid hemorrthage patients were divided into the treatment group and the control group with 40 patients in each group. The control group received traditional medical treatment and routine nursing. The treatment group received cerebrospinal fluid replacement.The incidence of complication,death and clinical effect were com-pared between the two groups and the data under χ2 test and t test. Results Each index in the treatment group was better than that of the control group. Conclusions Intensified nursing after cerebrospinal fluid replacement can improve treatment effect, alleviate prognosis and supply reference for future nursing work for this disease. Key words: Cerebrospinal fluid replacement; Subarachnoid hemorrhage; Nursing intervention

Research on the curative effect of cerebrospinal fluid replacement combining intravenous drips and intrathecal injection of amphotericin B in the treatment of cryptococcal neoformans meningitis

目的 研究脑脊液置换加静滴及鞘内注射两性毒素B治疗新型隐球菌性脑膜炎(简称隐脑)的疗效.方法 将收治的28例隐脑患者随机分为两组.A组脑脊液置换加静滴及鞘内注射两性霉素B为治疗组.B组仅静滴及鞘内注射两性霉素B为对照组,治疗共16周.以症状、体征、CSF常规、CSF培养及涂片为评定疗效.结果 治疗组比对照组疗效佳,两者比较差异有统计学意义(P＜0.05).结论 治疗组疗效佳,在基层医院不失为一种治疗新型隐球菌性脑膜炎的最佳方法之一,值得进一步研究.而两性霉素B仍为治疗隐脑最基本,最廉价和最重要的药物之一。

The effect of different volume cerebrospinal fluid replacement therapy on subarachnoid hemorrhage

目的 观察不同置换量对蛛网膜下腔出血脑脊液置换疗效的影响.方法将60例患者随机分为A组(大量脑脊液置换组)30例、B组(小量脑脊液置换组)30例.对A、B组腰椎穿刺用三通管行脑脊液置换,置换总量A组50～70 ml/次,B组10～30 ml/次.结果头痛缓解时间A组＜B组(P＜0.01);继发脑血管痉挛、脑积水的发生率A组＜B组(P＜0.05),但再出血的发生率两组差异无显著意义(P＞0.05);总有效率A组＞B组(P＜0.05).结论早期大量脑脊液置换治疗蛛网膜下腔出血的效果优于小量脑脊液置换,但都不能减少再出血的发生。

Cerebrospinal fluid may mediate CNS ischemic injury

BackgroundThe central nervous system (CNS) is extremely vulnerable to ischemic injury. The details underlying this susceptibility are not completely understood. Since the CNS is surrounded by cerebrospinal fluid (CSF) that contains a low concentration of plasma protein, we examined the effect of changing the CSF in the evolution of CNS injury during ischemic insult.MethodsLumbar spinal cord ischemia was induced in rabbits by cross-clamping the descending abdominal aorta for 1 h, 2 h or 3 h followed by 7 d of reperfusion. Prior to ischemia, rabbits were subjected to the following procedures; 1) CSF depletion, 2) CSF replenishment at 0 mmHg intracranial pressure (ICP), and 3) replacement of CSF with 8% albumin- or 1% gelatin-modified artificial CSF, respectively. Motor function of the hind limbs and histopathological changes of the spinal cord were scored. Post-ischemic microcirculation of the spinal cord was visualized by fluorescein isothiocyanate (FITC) albumin.ResultsThe severity of histopathological damage paralleled the neurological deficit scores. Paraplegia and associated histopathological changes were accompanied by a clear post-ischemic deficit in blood perfusion.Spinal cord ischemia for 1 h resulted in permanent paraplegia in the control group. Depletion of the CSF significantly prevented paraplegia. CSF replenishment with the ICP reduced to 0 mmHg, did not prevent paraplegia. Replacement of CSF with albumin- or gelatin-modified artificial CSF prevented paraplegia in rabbits even when the ICP was maintained at 10–15 mmHg.ConclusionWe conclude that the presence of normal CSF may contribute to the vulnerability of the spinal cord to ischemic injury. Depletion of the CSF or replacement of the CSF with an albumin- or gelatin-modified artificial CSF can be neuroprotective.

Cerebrospinal Fluid Shunt Infection by &lt;i&gt;Neisseria sicca&lt;/i&gt;

Neisseria sicca is considered to be a nonpathogenic oral saprophyte. Presented here is an unusual case of cerebrospinal fluid (CSF) shunt infection by N. sicca. Although medical management of the common community-acquired meningitides, including infection by Neisseria meningitidis, is often successful in patients with CSF shunts, removal and replacement of the infected shunt was necessary in this case.

Replacement and Absorption of Cerebrospinal Fluid in Normal and Vitamin a Deficient Calves

Cerebrospinal fluid (CSF) replacement and absorption were measured in vitamin A deficient and normal calves. Replacement estimates involved removal of CSF and determination of the time necessary to replace the volume removed, and absorption estimates involved reinjection of the fluid and estimation of the time necessary to absorb this volume. Thirty-five minutes were required to replace the 3.0ml of CSF in the normal animals, as compared to 15min in the deficient calves. When estimating absorption capacity in the deficient calves, the CSF pressure was highly stable in 11 of the 12 experiments and the trials were terminated between 25–60min. With normal calves the pressures returned to the original level in 17min. The results suggest that underabsorption represents a greater factor than overproduction as a cause of increased CSF pressure in vitamin A deficient calves.

Carotid angiography in the localisation of supratentorial neoplasms and hamartomata.

The high accuracy of carotid angiography in demonstrating such vascular lesions as intracranial aneurysms, arteriovenous malformations, subdural haematomata, and the like, has been well established. The large majority now agree that cerebral angiography is the method of choice in the diagnosis of these vascular lesions. The place of carotid angiography in the diagnosis and localisation of supratentorial neoplasms is not so well established, and there is much difference of opinion concerning the relative merits of ventriculography, pneumoencephalography, and carotid angiography. The following figures are taken from an investigation by Hodges and Holt (1) into the relative reliability of different radiological methods in localisation of brain tumours. As is apparent, ventriculography was used in a high proportion of cases. Cerebral angiography is stated to have an accuracy of 72 per cent, against an accuracy of 60.5 per cent for encephalography, the definition of accuracy as used in this review being a localisation sufficient to indicate correctly the site and size of bone flap adequate for approach to the tumour. It is very doubtful, however, if radiologists and neurological surgeons should be satisfied with this criterion of accuracy, as it ignores the question of correct assessment of the extension in depth of a lesion. A second tabulation illustrates the findings of an investigation into the relative accuracy of pneumography and angiography in the diagnosis of space-occupying lesions, conducted by Martin and Webster (2). Again, a high percentage of cases was submitted to ventriculography. Encephalography was found to have an accuracy of 36 per cent, but there were 20 diagnostic failures in 90 encephalograms. Since encephalography was performed by massive replacement of cerebrospinal fluid by air (100 to 150 c.c. exchange), this high percentage of diagnostic failures is perhaps not surprising. This also affects the estimate of accuracy of encephalography. It is noted, too, that 17 of the 82 cases examined by encephalography in this series were cases of subdural haematoma, for the investigation of which encephalography is hardly the method of choice. Only half of the subdural haematomata were localised by angiography, a remarkably low figure. It is apparent from the above surveys that the methods of selection of cases for the three procedures, encephalography, ventriculography, and carotid angiography, left something to be desired and also that the technique of encephalography, in one series at least, was of debatable value. We have found, by careful selection of cases for each of these three procedures and by careful elaboration of technique, including particularly a controlled fractional air injection of the Lindgren type for encephalography, that ventriculography is required in very few cases of intracranial space-occupying lesion, whether supratentorial or infratentorial.