Measurement Of Cerebrospinal Fluid Pressure Research Articles

Can Cerebrospinal Fluid Pressure Detect Catheter Complications in Patients Who Experience Loss of Effectiveness With Intrathecal Baclofen Therapy?

The catheter status of patients who presented with loss of intrathecal baclofen (ITB) therapy effectiveness was investigated using measurements of cerebrospinal fluid (CSF) pressure transmitted through the catheter fluid path to the pump. The aim of the study was to estimate the appropriate threshold separating catheter complications from "normal" catheter function, and to compare catheter status based on CSF pressure with the clinical diagnosis. This was a prospective, masked nonsignificant risk, research study. Patients (N = 47) received ITB for the treatment of severe spasticity and presented with symptoms of catheter malfunction. CSF pressure data were recorded using an external sensor connected to a needle inserted into the catheter access port. An algorithm calculated the energy of the variations in CSF pressure caused by respiration and heartbeat within the intrathecal space. These data were evaluated against a threshold that separated normal from abnormal catheter function. Catheter status based on the algorithm was compared with the clinical diagnosis. Complete data were available for 37 patients. Mean CSF pressure energy was significantly higher (p = 0.025; student t-test) for patients diagnosed with normal catheter function vs. catheters with complications. The CSF pressure algorithm matched the clinical diagnosis in 16 of 18 patients with catheter complications (sensitivity = 89%), and 13 of 19 patients with normal catheter function (specificity = 68%). In-clinic CSF pressure data acquisition is technically feasible. Overall, catheter status based on the algorithm demonstrated concordance with the clinical diagnosis in 29 of 37 patients (78.4%).

Current concepts and strategies in the diagnosis and management of idiopathic intracranial hypertension in adults.

Since obesity has become an epidemic in industrialized nations, idiopathic intracranial hypertension (IIH) is now a more common neuro-ophthalmic disorder that causes visual loss and headaches. This review highlights the new diagnostic criteria for IIH and the new insights into the pathophysiologic mechanisms of IIH. Key diagnostic and monitoring techniques for papilledema include not only neuroimaging and the measurement of cerebrospinal fluid (CSF) pressure, but also perimetry, optical coherence tomography, and ocular sonography. The main findings of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) support acetazolamide as the mainstay for medical therapy. CSF diversion procedures, endovascular venous sinus stenting, and optic nerve sheath fenestration are all surgical options when IIH is refractory to medical treatment or when it presents fulminantly. Future clinical trials comparing these procedures will help develop better paradigms in the surgical management of IIH.

Retinal venous pulsation: Expanding our understanding and use of this enigmatic phenomenon.

Retinal vein pulsation was first noted soon after the invention of the ophthalmoscope 170 years ago and was seen to change with cerebrospinal fluid pressure (CSFP) variation in the 1920s. The classical explanation for vein pulsation was that the cardiac cycle induced systolic peak in intraocular pressure (IOP) tended to intermittently collapse the retinal vein close to its exit in the central optic disk, causing pulsation to be counter-phase to IOP. Recently, improved ophthalmodynamometry and video recording techniques have allowed us to explore the fundamentals of retinal vein pulsation. This demonstrates that retinal venous collapse is in phase with both IOP and CSFP diastole, indicating the dependence upon CSFP pulse. We describe in some detail the mathematical and physical models of Starling resistors and how their results can be applied to understand the physiology of retinal vein pulsation. We discuss various techniques for measuring retinal venous pulsation, including a novel modified photo-plethysmographic technique developed in our laboratory. With these techniques, non-invasive measurement of CSFP is beginning to look feasible. Venous pulsation properties also have significant prognostic value in predicting long-term outcomes for both glaucoma and central retinal vein occlusion, as well as utility in other retinal vasculopathies and orbital disease. We demonstrate the potential use of modified photo-plethysmographic images in assessing these various disorders. A revised understanding of retinal vein pulse wave transmission along with improved measurement techniques may generate useful clinical tools for assessing these disorders.

Clinical Validation of a Transcranial Doppler-Based Noninvasive Intracranial Pressure Meter: A Prospective Cross-Sectional Study

Noninvasive intracranial pressure (ICP) measurement would represent a major advance for patients with neurological problems. The Vittamed ICP meter is an ultrasound-based device reported to have high agreement with lumbar puncture cerebrospinal fluid (CSF) pressure measurement. However, previous studies included mostly patients with normal levels of ICP. The purpose of our study was to perform an independent clinical validation study of a transcranial Doppler-based noninvasive ICP meter in patients anticipated to have a wide range of ICP. In a prospective cross-sectional design, we simultaneously measured ICP with the Vittamed device and the invasive lumbar CSF pressure. The operator of each procedure was blinded to the result of the other method. Data were analyzed using Bland-Altman plots, Pearson correlation coefficients, and receiver operator characteristic curves. Twenty-four independent paired measurements of Vittamed and lumbar CSF pressure were obtained; with mean absolute difference between paired measures of 4.5 mmHg (standard deviation 3.1). The 95% limits of agreement were-10.5 to+11.0. The systematic bias (mean of paired differences) was negligible at 0.25 mmHg. The sensitivity, specificity, and area under the curve for ICP >20 mmHg were 0.73, 0.77, and 0.71, respectively. The Vittamed ICP meter had fair agreement with lumbar CSF pressure measurement. The wide limits of agreement would preclude using this version of the device as a stand-alone method for ICP determination, but may be useful if combined with other ICP screening methods. Ongoing improvements to the Vittamed hardware and software may lead to improvements in accuracy and clinical utility of this device.

Dr. Ninan T. Mathew--A "Tribute" (1937-2015).

Dr. Ninan T. Mathew--A "Tribute" (1937-2015).

Poro-elastic modeling of Syringomyelia – a systematic study of the effects of pia mater, central canal, median fissure, white and gray matter on pressure wave propagation and fluid movement within the cervical spinal cord

Syringomyelia, fluid-filled cavities within the spinal cord, occurs frequently in association with a Chiari I malformation and produces some of its most severe neurological symptoms. The exact mechanism causing syringomyelia remains unknown. Since syringomyelia occurs frequently in association with obstructed cerebrospinal fluid (CSF) flow, it has been hypothesized that syrinx formation is mechanically driven. In this study we model the spinal cord tissue either as a poro-elastic medium or as a solid linear elastic medium, and simulate the propagation of pressure waves through an anatomically plausible 3D geometry, with boundary conditions based on in vivo CSF pressure measurements. Then various anatomic and tissue properties are modified, resulting in a total of 11 variations of the model that are compared. The results show that an open segment of the central canal and a stiff pia (relative to the cord) both increase the radial pressure gradients and enhance interstitial fluid flow in the central canal. The anterior median fissure, anisotropic permeability of the white matter, and Poisson ratio play minor roles.

Proof-of-Concept Prototype for Noninvasive Intracranial Pressure Monitoring Using Ocular Hemodynamics Under Applied Force

Studies have suggested that elevated cerebrospinal fluid (CSF) pressure can have a damaging effect on the optic nerve and visual acuity. There is need for a noninvasive CSF pressure measurement technique. A portable device for noninvasive intracranial pressure (ICP) monitoring would have a significant impact on clinical care. A proof-of-concept prototype is used to test the feasibility of a technique for monitoring ICP changes. The proposed methodology utilizes transcranial Doppler ultrasonography to monitor blood flow through the ophthalmic and central retinal arteries while forces are applied to the cornea by a controlled actuator. Control algorithms for the device were developed and tested using an integrated experimental platform. Preliminary results using tissue-mimicking materials show the ability to differentiate between materials of differing stiffness that simulates different levels of ICP. These experiments are an initial step toward a handheld noninvasive ICP monitoring device.

Diabetic retinopathy and estimated cerebrospinal fluid pressure. The Beijing eye study 2011

AbstractPurpose We tested the hypothesis whether prevalence and severity of diabetic retinopathy are associated with cerebrospinal fluid pressure (CSFP)Methods The population‐based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.69.8 years. Based on a previous study with lumbar cerebrospinal fluid pressure (CSFP) measurements, CSFP was calculated as CSFP[mmHg]=0.44xBody Mass Index[kg/m2]+0.16 Diastolic Blood Pressure[mmHg]–0.18xAge[Years]‐1.91.Results In binary regression analysis, presence of diabetic retinopathy was significantly associated with higher levels of HbA1c (P<0.001), higher blood concentration of glucose (P<0.001), longer known duration of diabetes mellitus (P<0.001), higher systolic blood pressure (P<0.001;), lower diastolic blood pressure (P<0.001), and higher CSFP (P=0.002). Severity of diabetic retinopathy was significantly associated with higher HbA1c value (P<0.001), higher blood concentration of glucose (), longer known duration of diabetes mellitus (P<0.001), lower level of education (P=0.001), lower diastolic blood pressure (P=0.002), higher systolic blood pressure (P=0.006), and higher CSFP (P=0.006).Conclusion Higher prevalence and severity of diabetic retinopathy were associated with higher estimated CSFP after adjusting for systemic parameters. Higher CSFP through a higher retinal vein pressure may lead to more marked retinal venous congestion and vascular leakage in diabetic retinae.

Intraocular pressure and estimated cerebrospinal fluid pressure. The Beijing Eye Study 2011.

PurposeTo examine a potential association between intraocular pressure (IOP) and cerebrospinal fluid pressure (CSFP) in a population-based setting.MethodsThe population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range: 50–93 years). A detailed ophthalmic examination was performed. Based on a previous study with lumbar cerebrospinal fluid pressure (CSFP) measurements, CSFP was calculated as CSFP [mm Hg] = 0.44×Body Mass Index [kg/m2]+0.16×Diastolic Blood Pressure [mm Hg]–0.18×Age [Years].ResultsIn multivariate analysis, IOP was associated with higher estimated CSFP (P<0.001; standardized correlation coefficient beta: 0.27; regression coefficient B: 0.20; 95% confidence interval (CI): 0.16, 0.24), after adjusting for thinner central corneal thickness (P<0.001; beta: 0.45; B: 0.04;95%CI: 0.04,0.04), smaller corneal curvature radius (P<0.001; beta:−0.11; B:−1.13;95%CI:−1.61,−0.64), shallower anterior chamber depth (P = 0.01; beta:−0.05; B:−0.33;95%CI:−0.59,−0.08) and longer axial length (P = 0.002; beta: 0.08; B: 0.20;95%CI: 0.08,0.32)), and after adjusting for the systemic parameters of higher pulse rate (P<0.001; beta: 0.08; B: 0.02;95%CI: 0.01,0.03), higher prevalence of arterial hypertension (P = 0.002; beta: 0.06; B: 0.32;95%CI: 0.12,0.53)), frequency of drinking alcohol (P = 0.02; beta: 0.04; B: 0.09;95%CI: 0.01,0.17), higher blood concentration of triglycerides (P = 0.001; beta: 0.06; B: 0.06;95%CI: 0.02,0.10) and cholesterol (P = 0.049; beta: 0.04; B: 0.08;95%CI: 0.00,0.17), and body mass index (P<0.001; beta:−0.13; B:−0.09;95%CI:−0.13,−0.06). In a parallel manner, estimated CSFP (mean: 10.8±3.7 mm Hg) was significantly associated with higher IOP (P<0.001; beta: 0.13; B: 0.18;95%CI: 0.13,0.23) after adjusting for rural region of habitation (P<0.001; beta:−0.37; B:−2.78;95%CI:−3.07,−2.48), higher systolic blood pressure (P<0.001; beta: 0.34; B: 0.06;95%CI: 0.05,0.07), higher pulse rate (P = 0.003; beta: 0.05; B: 0.02;95%CI: 0.01,0.03), taller body height (P<0.001; beta: 0.11; B: 0.05;95%CI: 0.03,0.07), higher blood concentration of cholesterol (P = 0.003; beta: 0.05; B: 0.17;95%CI: 0.06,0.28) and higher level of education (P = 0.003; beta: 0.09; B: 0.30;95%CI: 0.16,0.45).ConclusionsIOP was positively associated with estimated CSFP after adjusting for other ocular and systemic parameters. As a corollary, higher estimated CSFP was significantly associated with higher IOP in multivariate analysis. It fits with the notion that the arterial blood pressure, estimated CSFP and IOP are physiologically correlated with each other.

Cryptococcal Meningitis Management in Tanzania With Strict Schedule of Serial Lumber Punctures Using Intravenous Tubing Sets

Cryptococcal meningitis (CM) has a mortality rate of ∼70% among HIV-infected adults in low-income countries. Controlling intracranial pressure (ICP) is essential in CM, but it is difficult in low-income countries because manometers and practical ICP management protocols are lacking. As part of a continuous quality improvement project, our Tanzanian hospital initiated a new protocol for ICP management for CM. All adult inpatients with CM are included in a prospective patient registry. At the time of analysis, this registry included data from 2 years before the initiation of this new ICP management protocol and for a 9-month period after. ICP was measured at baseline and at days 3, 7, and 14 by both manometer and intravenous (IV) tubing set. All patients were given IV fluconazole according to Tanzanian treatment guidelines and were followed until 30 days after admission. Among adult inpatients with CM, 32 of 35 patients (91%) had elevated ICP on admission. Cerebrospinal fluid pressure measurements using the improvised IV tubing set demonstrated excellent agreement (r = 0.96) with manometer measurements. Compared with historical controls, the new ICP management protocol was associated with a significant reduction in 30-day mortality (16/35 [46%] vs. 48/64 [75%] in historical controls; hazard ratio = 2.1 [95% CI: 1.1 to 3.8]; P = 0.018]. Increased ICP is almost universal among HIV-infected adults admitted with CM in Tanzania. Intensive ICP management with a strict schedule of serial lumbar punctures reduced in-hospital mortality compared with historical controls. ICP measurement with IV tubing sets may be a good alternative in resource-limited health facilities where manometers are not available.

Diabetic retinopathy and estimated cerebrospinal fluid pressure. The Beijing Eye Study 2011.

PurposeThe cerebrospinal fluid pressure (CSFP) is a major determinant of central retinal vein pressure and thus of retinal capillary pressure. We tested the hypothesis whether prevalence and severity of diabetic retinopathy are associated with CSFP.MethodsThe population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years. A detailed ophthalmic examination was performed including fundus photography for the assessment of diabetic retinopathy according. Based on a previous study with lumbar cerebrospinal fluid pressure (CSFP) measurements, CSFP was calculated as CSFP[mmHg] = 0.44xBody Mass Index[kg/m2]+0.16 Diastolic Blood Pressure[mmHg]–0.18xAge[Years]−1.91.ResultsIn binary regression analysis, presence of diabetic retinopathy was significantly associated with higher levels of HbA1c (P<0.001; regression coefficient B:0.25; odds ratio (OR):1.28; 95% confidence interval (CI):1.15,1.43), higher blood concentration of glucose (P<0.001; B:0.40;OR:1.49;95%CI:1.36,1.63), longer known duration of diabetes mellitus (P<0.001; B:0.14;OR:1.15; 95%CI:1.11,1.19), higher systolic blood pressure (P<0.001; B:0.03;OR:1.03;95%CI:1.02,1.04), lower diastolic blood pressure (P<0.001; B:−0.06;OR:0.94;95%CI:0.91,0.97), and higher CSFP (P = 0.002; B:0.13;OR:1.14;95%CI:1.05,1.24). Severity of diabetic retinopathy was significantly associated with higher HbA1c value (P<0.001; standardized coefficient beta: 0.19; correlation coefficient B: 0.07;95%CI:0.05,0.08), higher blood concentration of glucose (P<0.001; beta:0.18;B:0.04;95%CI:0.04,0.05), longer known duration of diabetes mellitus (P<0.001; beta:0.20;B:0.03;95%CI:0.02,0.03), lower level of education (P = 0.001; beta:−0.05;B:−0.02;95%CI:−0.03,−0.01), lower diastolic blood pressure (P = 0.002; beta:−0.08;B:−0.001;95%CI:−0.004,−0.001), higher systolic blood pressure (P = 0.006; beta:0.06;B:0.001;95%CI:0.000,0.001), and higher CSFP (P = 0.006; beta:0.06;B:0.006;95%CI:0.002,0.010).ConclusionsHigher prevalence and severity of diabetic retinopathy were associated with higher estimated CSFP after adjusting for systemic parameters. Higher CSFP through a higher retinal vein pressure may lead to more marked retinal venous congestion and vascular leakage in diabetic retinae.

Body Height, Estimated Cerebrospinal Fluid Pressure and Open-Angle Glaucoma. The Beijing Eye Study 2011

PurposeTo examine potential associations between body height, cerebrospinal fluid pressure (CSFP), trans-lamina cribrosa pressure difference (TLCPD) and prevalence of open-angle glaucoma (OAG) in a population-based setting.MethodsThe population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range:50–93 years). A detailed ophthalmic examination was performed. Based on a previous study with lumbar cerebrospinal fluid pressure (CSFP) measurements, CSFP was calculated as CSFP[mmHg] = 0.44×Body Mass Index[kg/m2]+0.16×Diastolic Blood Pressure[mmHg]-0.18×Age[Years]-1.91ResultsData of IOP and CSFP were available for 3353 (96.7%) subjects. Taller body height was associated with higher CSFP (P<0.001; standardized correlation coefficient beta:0.13; regression coefficient B:0.29; 95% confidence interval (CI):0.25,0.33) after adjusting for male gender, urban region of habitation, higher educational level, and pulse rate. If TLCPD instead of CSFP was added, taller body height was associated with lower TLCPD (P<0.001;beta:−0.10;B:−0.20;95%CI:−0.25,−0.15). Correspondingly, higher CSFP was associated with taller body height (P = 0.003;beta:0.02;B:0.01;95%CI:0.00,0.02), after adjusting for age, gender, body mass index, pulse, systolic blood pressure, and blood concentration of cholesterol. If IOP was added to the model, higher CSFP was associated with higher IOP (P<0.001;beta:0.02;B:0.02;95%CI:0.01,0.03). TLCPD was associated with lower body height (P = 0.003;beta:−0.04;B −0.02,95%CI:−0.04,−0.01) after adjusting for age, body mass index, systolic blood pressure, pulse, blood concentrations of triglycerides, axial length, central corneal thickness, corneal curvature radius, and anterior chamber depth. Adding the prevalence of OAG to the multivariate analysis revealed, that taller body height was associated with a lower OAG prevalence (P = 0.03;beta:−0.03;B:−1.20;95%CI:−2.28,−0.12) after adjusting for educational level and gender.ConclusionsTaller body height was associated with higher CSFP and lower TLCPD (and vice versa), after adjusting for systemic and ocular parameters. Parallel to the associations between a higher prevalence of glaucoma with a lower CSFP or higher TLCPD, taller body height was associated with a lower prevalence of OAG.

Improved diagnostic value of a TCD-based non-invasive ICP measurement method compared with the sonographic ONSD method for detecting elevated intracranial pressure

Objectives:To compare the diagnostic reliability of optic nerve sheath diameter (ONSD) ultrasonography with a transcranial Doppler (TCD)-based absolute intracranial pressure (ICP) value measurement method for detection of elevated ICP in neurological patients. The ONSD method has been only tested previously on neurosurgical patients.Methods:A prospective clinical study of a non-invasive ICP estimation method based on ONSD correlation with ICP and an absolute ICP value measurement method based on a two-depth TCD technology has recruited 108 neurological patients. Ninety-two of these patients have been enrolled in the final analysis of the diagnostic reliability of ONSD ultrasonography and 85 patients using the absolute ICP value measurement method. All non-invasive ICP measurements were compared with ‘Gold Standard’ invasive cerebrospinal fluid (CSF) pressure measurements obtained by lumbar puncture. Receiver-operating characteristic (ROC) analysis has been used to investigate the diagnostic value of these two methods.Results:The diagnostic sensitivity, specificity, and the area under the ROC curve (AUC) of the ONSD method for detecting elevated intracranial pressure (ICP >14·7 mmHg) were calculated using a cutoff point of ONSD at 5·0 mm and found to be 37·0%, 58·5%, and 0·57, respectively. The diagnostic sensitivity, specificity, and AUC for the non-invasive absolute ICP measurement method were calculated at the same ICP cutoff point of 14·7 mmHg and were determined to be 68·0%, 84·3%, and 0·87, respectively.Conclusions:The non-invasive ICP measurement method based on two-depth TCD technology has a better diagnostic reliability on neurological patients than the ONSD method when expressed by the sensitivity and specificity for detecting elevated ICP >14·7 mmHg.

Spontaneous sphenoid lateral recess cerebrospinal fluid leaks arise from intracranial hypertension, not Sternberg's canal

Spontaneous cerebrospinal fluid (CSF) leaks/encephaloceles are proven to be associated with intracranial hypertension by objective measurements of CSF pressure during or following endoscopic repair. A common area of involvement is a pneumatized lateral recess of the sphenoid (LRS) sinus, where prolonged intracranial pressures lead to arachnoid pits and subsequent development of skull-base defects. Even though the LRS is never present at birth, a "congenital" cause of these leaks due to a persistent Sternberg's (lateral craniopharyngeal) canal continues to be erroneously perpetuated in the literature. The objective of this study was to eliminate the myths defining these leaks as congenital in nature. Evaluation of LRS CSF leaks present within a multiinstitutional case series was performed. Data regarding demographics, body mass index (BMI), radiologic evaluation of intracranial hypertension, and direct intracranial pressure measurements (when available) were collected. Data evaluation identified 77 LRS CSF leaks in 59 patients (mean age 52 years). Obesity was present in 83% of individuals (mean BMI 36) and 81% were females. Radiologic evidence of intracranial hypertension (eg, empty sella, dilated optic nerve sheaths, and scalloped/attenuated bone) was present on 96% of preoperative computed tomography (CT) and/or magnetic resonance imaging (MRI) scans. Opening or postsurgical lumbar drain or ventriculostomy pressure measurements were elevated in 95% of patients (mean 27.7; range, 9-50 cmH2 O). This study provides objective evidence that LRS CSF leaks are secondary to erosions from intracranial hypertension and refutes the myth regarding a congenital origin from Sternberg's canal.

Trans-Lamina Cribrosa Pressure Difference and Open-Angle Glaucoma. The Central India Eye and Medical Study

PurposeTo assess associations of the trans-lamina cribrosa pressure difference (TLCPD) with glaucomatous optic neuropathy.MethodsThe population-based Central India Eye and Medical Study included 4711 subjects. Based on a previous study with lumbar cerebrospinal fluid pressure (CSFP) measurements, CSFP was calculated as CSFP[mmHg] = 0.44 Body Mass Index[kg/m2]+0.16 Diastolic Blood Pressure[mmHg]−0.18×Age[Years] −1.91. TLCPD was IOP–CSFP.ResultsMean TLCPD was 3.64±4.25 mm Hg in the non-glaucomatous population and 9.65±8.17 mmHg in the glaucomatous group. In multivariate analysis, TLCPD was associated with older age (P<0.001; standardized coefficient beta:0.53; regression coefficient B:0.18; 95% confidence interval (CI):0.17, 0.18), lower body mass index (P<0.001; beta: −0.28; B: −0.36; 95%CI: −0.38, −0.31), lower diastolic blood pressure (P<0.001; beta: −0.31; B: −0.12; 95%CI: −0.13, −0.11), higher pulse (P<0.001; beta:0.05; B:0.02; 95%CI:0.01,0.2), lower body height (P = 0.02; beta: −0.02; B: −0.01; 95%CI: −0.02,0.00), higher educational level (P<0.001; beta:0.04; B:0.15; 95%CI:0.09,0.22), higher cholesterol blood concentrations (P<0.001; beta:0.04; B:0.01; 95%CI:0.01,0.01), longer axial length (P = 0.006; beta:0.03; B:0.14; 95%CI:0.04,0.24), thicker central cornea (P<0.001; beta:0.15; B:0.02; 95%CI:0.02,0.02), higher corneal refractive power (P<0.001; beta:0.07; B:0.18; 95%CI:0.13,0.23) and presence of glaucomatous optic neuropathy (P<0.001; beta:0.11; B:3.43; 95%CI:2.96,3.99). Differences between glaucomatous subjects and non-glaucomatous subjects in CSFP were more pronounced for open-angle glaucoma (OAG) than for angle-closure glaucoma (ACG) (3.0 mmHg versus 1.8 mmHg), while differences between glaucomatous subjects and non-glaucomatous subjects in IOP were higher for ACG than for OAG (8.5 mmHg versus 3.0 mmHg). Presence of OAG was significantly associated with TLCPD (P<0.001; OR:1.24; 95%CI:1.19,1.29) but not with IOP (P = 0.08; OR:0.96; 95%CI:0.91,1.00). Prevalence of ACG was significantly associated with IOP (P = 0.04; OR:1.19; 95%CI:1.01,1.40) but not with TLCPD (P = 0.92).ConclusionsIn OAG, but not in ACG, calculated TLCPD versus IOP showed a better association with glaucoma presence and amount of glaucomatous optic neuropathy. It supports the notion of a potential role of low CSFP in the pathogenesis of open-angle glaucoma.

Changes of cerebrospinal fluid pressure after thoracic endovascular aortic repair

Background Decreasing the intracranial pressure has been advocated as one of the major protective strategies to prevent spinal cord ischemia after endovascular aortic repair. However, the actual changes of cerebrospinal fluid (CSF) pressure and its relation with spinal cord ischemia have been poorly understood. We performed CSF pressure measurements and provisional CSF withdrawal after thoracic endovascular aortic repair, and compared the changes of CSF pressure in high risk patients and in patients with new onset paraplegia and paraparesis. Methods Four hundred and nineteen patients were evaluated for the risk of spinal cord ischemia after thoracic endovascular aortic repair. Patients with identified risk factors before the procedure constituted group H and received prophylactic sequential CSF pressure measurement and CSF withdrawal. Patients who actually developed spinal cord ischemia constituted group P and received rescue CSF pressure measurements and CSF withdrawal. Results Among the 419 patients evaluated, 17 were graded as high risk. Four patients actually developed spinal cord ischemia after endovascular repair. The incidence of spinal cord ischemia in this investigation was 0.9%. The patients who actually developed spinal cord ischemia had no identified risk factors and had elevated CSF pressure, ranging from 15.4 to 30.0 mmHg. Six of the 17 patients graded as high risk had elevated CSF pressure: &gt;20 mmHg in two patients and &gt;15 mmHg in four patients. Sequential CSF pressure measurements and provisional withdrawal successfully decrease CSF pressure and prevented symptomatic spinal cord ischemia in high-risk patients. However, these measurements could only successfully reverse the neurologic deficit in two of the patients who actually developed spinal cord ischemia. Conclusions Cerebrospinal fluid pressure was elevated in patients with spinal cord ischemia after thoracic endovascular aortic repair. Sequential measurements of CSF pressure and provisional withdrawal of CSF decreased CSF pressure effectively in high risk patients and provided effective prevention of spinal cord ischemia. Risk factor identification and prophylactic measurements play the key role in prevention of spinal cord ischemia after thoracic endovascular aortic repair.

Valsalva manoeuver, intra‐ocular pressure, cerebrospinal fluid pressure, optic disc topography: Beijing intracranial and intra‐ocular pressure study

To assess whether a Valsalva manoeuver influences intra-ocular pressure (IOP), cerebrospinal fluid pressure (CSF-P) and, by a change in the trans-laminar cribrosa pressure difference, optic nerve head morphology. In the first part of the study, 20 neurological patients (study group 'A') underwent measurement of IOP and lumbar CSF-P measurement in a lying position before and during a Valsalva manoeuver. In the second study part, 20 healthy subjects (study group 'B') underwent ocular tonometry and confocal scanning laser tomography of the optic nerve head before and during a Valsalva manoeuver. During the Valsalva manoeuver in study group 'A', the increase in CSF-P by 10.5±2.7mmHg was significantly (p<0.001) higher than the increase in IOP by 1.9±2.4mmHg. The change in CSF-P was not significantly (p=0.61) correlated with the change in IOP. During the Valsalva manoeuver in study group 'B', IOP increased by 4.5±4.2mmHg and optic cup volume (p<0.001), cup/disc area ratio (p=0.02), cup/disc diameter ratio (p=0.03) and maximum optic cup depth (p=0.01) significantly decreased, while neuroretinal rim volume (p=0.005) and mean retinal nerve fibre layer thickness (p=0.02) significantly increased. The Valsalva manoeuver-associated short-term increase in CSF-P was significantly larger than a simultaneous short-term increase in IOP. It led to a Valsalva manoeuver-associated decrease or reversal of the trans-laminar cribrosa pressure difference, which was associated with a change in the three-dimensional optic nerve head morphology: optic cup-related parameters decreased and neuroretinal rim-related parameters enlarged. These findings may be of interest for the pathogenesis of glaucomatous optic neuropathy.

Rat model of spinal cord injury preserving dura mater integrity and allowing measurements of cerebrospinal fluid pressure and spinal cord blood flow

Cerebrospinal fluid (CSF) pressure elevation may worsen spinal cord ischaemia after spinal cord injury (SCI). We developed a rat model to investigate relationships between CSF pressure and spinal cord blood flow (SCBF). Male Wistar rats had SCI induced at Th10 (n = 7) or a sham operation (n = 10). SCBF was measured using laser-Doppler and CSF pressure via a sacral catheter. Dural integrity was assessed using subdural methylene-blue injection (n = 5) and myelography (n = 5). The SCI group had significantly lower SCBF (p < 0.0001) and higher CSF pressure (p < 0.0001) values compared to the sham-operated group. Sixty minutes after SCI or sham operation, CSF pressure was 8.6 ± 0.4 mmHg in the SCI group versus 5.5 ± 0.5 mmHg in the sham-operated group. No dural tears were found after SCI. Our rat model allows SCBF and CSF pressure measurements after induced SCI. After SCI, CSF pressure significantly increases.

Low Cerebrospinal Fluid Pressure in the Pathogenesis of Primary Open-Angle Glaucoma

Previous experimental and clinical investigations have suggested that some patients with primary open-angle glaucoma may have an abnormally low orbital cerebrospinal fluid pressure (CSFP). A meta-analysis of available clinical data showed a marked overlap in lumbar CSFP measurements between patients with normal-tension glaucoma and healthy subjects, so that the question arises as to which additional factors play a role in the pathogenesis of glaucomatous optic neuropathy.

Rotating Distraction Osteogenesis to Enlarge the Skull Space

Distraction osteogenesis has been used to treat diminished skull space caused by craniosynostosis. Our report investigated the relationship between space volume change by computer technology and the intracranial pressure change. Cerebrospinal fluid (CSF) regular test and CSF biochemistry test were also performed to ensure the safety of distraction process. Seven minipigs, weighing 15 to 20 kilograms, were chosen; 4 × 3 cm bone flap was lifted in the left parietal bone. The dura was carefully protected. The distractor and assisted apparatus were implanted. Distraction was started with 10-day latency, 1 mm/d distraction rates for 10 days. Twelve weeks after distraction, the distraction device and the assist apparatus were removed. All pigs underwent 3-dimensional computerized scans of the craniofacial skeleton, CSF pressure measurement, CSF regular test, and CSF biochemistry test before operation, after 7 days' operation, immediately after distraction was finished, 4 weeks after distraction, 8 weeks after distraction, and 12 weeks after distraction. The 3-dimensional datum was collected, and volume change of skull was measured by 3-dimensional medicine surface rendering software. All pigs tolerated the procedure. The mean volume 12 weeks after distraction was 87.93 ± 3.11 cm, which was also significantly higher than 79.46 ± 3.15 cm that of before operation (P < 0.001). The CSF pressure becomes maxim after 7 days' operation. The CSF pressure went down immediately after distraction was finished. Then, the CSF pressure kept stable but lower than the CSF pressure before the operation except 1 pig whose CSF pressure after operation was higher than the CSF pressure before the operation. Cerebrospinal fluid regular test and CSF biochemistry test show stable results, and the WBC does not rise during the whole process. The distraction osteogenesis is an efficient and safe method to enlarge the intracranial volume. The assisted apparatus of distraction is useful for rotating distraction. Three-dimensional DICOM datum and 3-dimensional medicine surface rendering are efficient for measurement of skull volume.