Higher Concentration of Taenia Antigens in the CSF is Related to Slight Ventricle Enlargement and Periventricular Neuronal Decrease in Young Rats

Purpose Experimental models might help understand the pathophysiology of neurocysticercosis-associated hydrocephalus. The present study aimed to compare the extent of hydrocephalus and tissue damage in rats with subarachnoid inoculation of different concentrations of Taenia crassiceps cyst proteins. Methods Sixty young rats were divided into two groups: low- and high-concentration groups. The animals in the low concentration group received 0.02ml of 2.4mg/ml T. crassiceps cyst proteins while those in the high concentration group received 0.02 ml of 11.6mg/ml T. crassiceps cyst proteins. The animals underwent magnetic resonance imaging at 1, 3, and 6 months postinoculation to assess the ventricle volume. Morphological assessment was performed at the end of the observation period. Results Repeated measures of ventricle volumes at 1, 3, and 6 months showed progressive enlargement of the ventricles. At 1 and 3 months, we observed no differences in ventricle volumes between the 2 groups. However, at 6 months, the ventricles were larger in the high concentration group (median » 3.86mm3, range: 2.37­12.68) compared with the low concentration group (median » 2.00mm3, range: 0.37­11.57), p » 0.003. The morphological assessment revealed a few inflammatory features in both groups. However, the density of oligodendrocytes and neurons within the periventricular region was lower in the high concentration group (5.18 versus 9.72 for oligodendrocytes and 15.69 versus 21.00 for neurons; p < 0.001 for both). Conclusion Our results suggest that, in rats, a higher concentration of T. crassiceps cyst proteins in the subarachnoid space could induce ventricle enlargement and reduce the number of neurons within the periventricular area.

Repeated subarachnoid administrations of allogeneic human umbilical cord mesenchymal stem cells for spinal cord injury: a phase 1/2 pilot study.

BACKGROUND AIMS: Stem cell transplantation is a potential treatment for intractable spinal cord injury (SCI), and allogeneic human umbilical cord mesenchymal stem cells (hUC-MSCs) are a promising candidate because of the advantages of immune privilege, paracrine effect, immunomodulatory function, convenient collection procedure and little ethical concern, and there is an urgent need to develop a safe and effective protocol regarding their clinical application. METHODS: A prospective, single-center, single-arm study in which subjects received four subarachnoid transplantations of hUC-MSCs (1 × 106 cells/kg) monthly and were seen in follow-up four times (1, 3, 6 and 12 months after final administration) was conducted. At each scheduled time point, safety and efficacy indicators were collected and analyzed accordingly. Adverse events (AEs) were used as a safety indicator. American Spinal Injury Association (ASIA) and SCI Functional Rating Scale of the International Association of Neurorestoratology (IANR-SCIFRS) total scores at the fourth follow-up were determined as primary efficacy outcomes, whereas these two indicators at the remaining time points as well as scores of pinprick, light touch, motor and sphincter, muscle spasticity and spasm, autonomic system, bladder and bowel functions, residual urine volume (RUV) and magnetic resonance imaging (MRI) were secondary efficacy outcomes. Subgroup analysis of primary efficacy indicators was also performed. RESULTS: Safety and efficacy assessments were performed on 102 and 41 subjects, respectively. Mild AEs involving fever (14.1%), headache (4.2%), transient increase in muscle tension (1.6%) and dizziness (1.3%) were observed following hUC-MSC transplantation and resolved thoroughly after conservative treatments. There was no serious AE. ASIA and IANR-SCIFRS total scores revealed statistical increases when compared with the baselines at different time points during the study, mainly reflected in the improvement of pinprick, light touch, motor and sphincter scores. Moreover, subjects showed a continuous and remarkable decrease in muscle spasticity. Regarding muscle spasm, autonomic system, bladder and bowel functions, RUV and MRI, data/imaging at final follow-up showed significant improvements compared with those at first collection. Subgroup analysis found that hUC-MSC transplantation improved neurological functions regardless of injury characteristics, including level, severity and chronicity. CONCLUSIONS: The authors' present protocol demonstrates that intrathecal administration of' allogeneic hUC-MSCs at a dose of 106 cells/kg once a month for 4 months is safe and effective and leads to significant improvement in neurological dysfunction and recovery of quality of life.

Longitudinal morphological changes during recovery from brain deformation due to idiopathic normal pressure hydrocephalus after ventriculoperitoneal shunt surgery.

The present study aimed to examine time-dependent change in cerebrospinal fluid distribution and various radiological indices for evaluating shunt effectiveness in patients with idiopathic normal pressure hydrocephalus (iNPH). This study included 54 patients with iNPH who underwent MRI before and after ventriculoperitoneal shunt surgery. The volume of the total ventricles and subarachnoid spaces decreased within 1 month after shunting. However, more than 1 year after shunting, the volume of the total ventricles decreased, whereas that of the total subarachnoid spaces increased. Although cerebrospinal fluid distribution changed considerably throughout the follow-up period, the brain parenchyma expanded only 2% from the baseline brain volume within 1 month after shunting and remained unchanged thereafter. The volume of the convexity subarachnoid space markedly increased. The changing rate of convexity subarachnoid space per ventricle ratio (CVR) was greater than that of any two-dimensional index. The brain per ventricle ratio (BVR), callosal angle and z-Evans index continued gradually changing, whereas Evans index did not change throughout the follow-up period. Both decreased ventricular volume and increased convexity subarachnoid space volume were important for evaluating shunt effectiveness. Therefore, we recommend CVR and BVR as useful indices for the diagnosis and evaluation of treatment response in patients with iNPH.

Effect of extradural constriction on CSF flow in rat spinal cord.

BACKGROUND: Fluid homeostasis in the central nervous system (CNS) is essential for normal neurological function. Cerebrospinal fluid (CSF) in the subarachnoid space and interstitial fluid circulation in the CNS parenchyma clears metabolites and neurotransmitters and removes pathogens and excess proteins. A thorough understanding of the normal physiology is required in order to understand CNS fluid disorders, including post-traumatic syringomyelia. The aim of this project was to compare fluid transport, using quantitative imaging of tracers, in the spinal cord from animals with normal and obstructed spinal subarachnoid spaces. METHODS: A modified extradural constriction model was used to obstruct CSF flow in the subarachnoid space at the cervicothoracic junction (C7-T1) in Sprague-Dawley rats. Alexa-Fluor 647 Ovalbumin conjugate was injected into the cisterna magna at either 1 or 6 weeks post-surgery. Macroscopic and microscopic fluorescent imaging were performed in animals sacrificed at 10 or 20 min post-injection. Tracer fluorescence intensity was compared at cervical and thoracic spinal cord levels between control and constriction animals at each post-surgery and post-injection time point. The distribution of tracer around arterioles, venules and capillaries was also compared. RESULTS: Macroscopically, the fluorescence intensity of CSF tracer was significantly greater in spinal cords from animals with a constricted subarachnoid space compared to controls, except at 1 week post-surgery and 10 min post-injection. CSF tracer fluorescence intensity from microscopic images was significantly higher in the white matter of constriction animals 1 week post surgery and 10 min post-injection. At 6 weeks post-constriction surgery, fluorescence intensity in both gray and white matter was significantly increased in animals sacrificed 10 min post-injection. At 20 min post-injection this difference was significant only in the white matter and was less prominent. CSF tracer was found predominantly in the perivascular spaces of arterioles and venules, as well as the basement membrane of capillaries, highlighting the importance of perivascular pathways in the transport of fluid and solutes in the spinal cord. CONCLUSIONS: The presence of a subarachnoid space obstruction may lead to an increase in fluid flow within the spinal cord tissue, presenting as increased flow in the perivascular spaces of arterioles and venules, and the basement membranes of capillaries. Increased fluid retention in the spinal cord in the presence of an obstructed subarachnoid space may be a critical step in the development of post-traumatic syringomyelia.

Influence of the State of the Subarachnoid Space of the Cranial Base in Hydrocephalus Resolution after Endoscopy.

Objective To compare the resolution rate of hydrocephalus after endoscopy (predominantly endoscopic third ventriculostomy [ETV]) using flexible endoscopes during a 5-year period in patients with a permeable and a nonpermeable subarachnoid space (SAS). Material and Methods We conducted a retrospective cohort study of the videos and records of 150 hydrocephalic patients chosen randomly who underwent ETV (and other endoscopic procedures) with a flexible endoscope. The patients were classified into two groups based on the neuroendoscopic findings. The first group included patients with a permeable SAS, and the second group included patients with a nonpermeable SAS. A normal SAS or one with slight arachnoiditis was considered permeable. Adhesive arachnoiditis and immature or mechanically obliterated SASs were considered nonpermeable. Results We found a success rate of 70% in patients with a permeable SAS versus 33% in patients with a nonpermeable SAS. The baseline characteristics of both groups were homogeneous. We obtained a statistically significant difference (p < 0.0001) with hazard ratio (HR) 3.42 (95% confidence interval [CI], 1.88-6.22). Another important factor involved was age that showed a statistically significant difference (p < 0.0018) with HR 3.28 (95% CI, 1.55-6.93). Conclusion The permeability of the SAS is an important prognostic factor in the resolution rate of hydrocephalus after ETV (and other endoscopic procedures) using flexible neuroendoscopes. Therefore we recommend that the characteristics of the SAS be examined following every endoscopic procedure for hydrocephalus to identify patients at risk of recurrence.

Sustained high-pressure in the spinal subarachnoid space while arterial expansion is low may be linked to syrinx development.

Syringomyelia (a spinal cord cyst) usually develops as a result of conditions that cause cerebrospinal fluid (CSF) obstruction. The mechanism of syrinx formation and enlargement remains unclear, though previous studies suggest that the fluid enters via the perivascular spaces (PVS) of the penetrating arteries of the spinal cord, and that alterations in the CSF pulse timing and pressure could contribute to enhanced PVS inflow. This study uses an idealised computational model of the PVS to investigate the factors that influence peri-arterial fluid flow. First, we used three sample patient-specific models to explore whether changes in subarachnoid space (SAS) pressures in individuals with and without syringomyelia could influence PVS inflow. Second we conducted a parametric study to determine how features of the CSF pulse altered perivascular fluid, including alterations to timing and magnitude of the peak SAS pressure, the timing of reversal from high to low pressure (diastolic phase), and the area under the pressure-time curve. The model for the patient with syringomyelia had higher net CSF inflow to the PVS than the two subjects without syringomyelia. In the parametric study, only increasing the area under the high pressure region of the SAS pulse substantially increased PVS inflow, when coupled with a temporal shift in arterial and SAS pulses. This suggests that a period of sustained high SAS pressure while arterial diameter is low may increase net CSF pumping into the PVS.

Cisternostomy for Traumatic Brain Injury: Pathophysiologic Mechanisms and Surgical Technical Notes.

OBJECTIVE: Traumatic brain injury (TBI) is one of the major challenges in health care, representing the third most frequent cause of death. Current optimal management is based on a progressive, target-driven approach combining both medical and surgical treatment strategies. Here we describe cisternostomy, an emerging surgical treatment for the treatment of TBI. METHODS: Cisternostomy is a novel technique that incorporates knowledge of skull base and microvascular surgery. By opening the brain cisterns to atmospheric pressure, the technique could decrease the intracranial pressure due to a backshift of the cerebrospinal fluid (CSF) from the swollen brain to the cisterns through the Virchow-Robin spaces. RESULTS: An increasing number of evidence has demonstrated a paravascular pathway that facilitates CSF flow from the subarachnoid space through the brain parenchyma. This network of paravascular channels, termed as the "glymphatic" pathway, reduces considerably its activity after TBI, thus participating in the development of brain edema formation. Cisternostomy, by opening the brain cisterns to atmospheric pressure, could decrease the intracerebral pressure due to a backshift of CSF through the Virchow-Robin spaces. CONCLUSIONS: In the current common practice, the surgical measures for TBI include external ventricular drainage insertion and decompressive craniectomy. There is evidence that both of these measures reduce intracranial pressure but the effect on the outcome, particularly in the long term, is equivocal. A new line of evidence supports cisternostomy as an emerging surgical treatment for TBI.

Aquaporin-4 expression and blood-spinal cord barrier permeability in canalicular syringomyelia.

OBJECT: Noncommunicating canalicular syringomyelia occurs in up to 65% of patients with Chiari malformation Type I. The pathogenesis of this type of syringomyelia is poorly understood and treatment is not always effective. Although it is generally thought that syringomyelia is simply an accumulation of CSF from the subarachnoid space, the pathogenesis is likely to be more complex and may involve cellular and molecular processes. Aquaporin-4 (AQP4) has been implicated in numerous CNS pathological conditions involving fluid accumulation, including spinal cord edema. There is evidence that AQP4 facilitates the removal of extracellular water following vasogenic edema. The aim of this study was to investigate AQP4 expression and the structural and functional integrity of the blood-spinal cord barrier (BSCB) in a model of noncommunicating canalicular syringomyelia. METHODS: A kaolin-induced model of canalicular syringomyelia was used to investigate BSCB permeability and AQP4 expression in 27 adult male Sprague-Dawley rats. Control groups consisted of nonoperated, laminectomy-only, and saline-injected animals. The structural integrity of the BSCB was assessed using immunoreactivity to endothelial barrier antigen. Functional integrity of the BSCB was assessed by extravasation of systemically injected horseradish peroxidase (HRP) at 1, 3, 6, or 12 weeks after surgery. Immunofluorescence was used to assess AQP4 and glial fibrillary acidic protein (GFAP) expression at 12 weeks following syrinx induction. RESULTS: Extravasation of HRP was evident surrounding the central canal in 11 of 15 animals injected with kaolin, and in 2 of the 5 sham-injected animals. No disruption of the BSCB was observed in laminectomy-only controls. At 12 weeks the tracer leakage was widespread, occurring at every level rostral to the kaolin injection. At this time point there was a decrease in EBA expression in the gray matter surrounding the central canal from C-5 to C-7. Aquaporin-4 was expressed in gray- and white-matter astrocytes, predominantly at the glia limitans interna and externa, and to a lesser extent around neurons and blood vessels, in both control and syrinx animals. Expression of GFAP and APQ4 directly surrounding the central canal in kaolin-injected animals was variable and not significantly different from expression in controls. CONCLUSIONS: This study demonstrated a prolonged disruption of the BSCB directly surrounding the central canal in the experimental model of noncommunicating canalicular syringomyelia. The disruption was widespread at 12 weeks, when central canal dilation was most marked. Loss of integrity of the barrier with fluid entering the interstitial space of the spinal parenchyma may contribute to enlargement of the canal and progression of syringomyelia. Significant changes in AQP4 expression were not observed in this model of canalicular syringomyelia. Further investigation is needed to elucidate whether subtle changes in AQP4 expression occur in canalicular syringomyelia.

Post-traumatic syringomyelia: CSF hydrodynamic changes following spinal cord injury are the driving force in the development of PTSM.

Post-traumatic syringomyelia (PTSM) is a disorder that occurs infrequently following spinal cord injury (SCI), characterized by progressive neurological deterioration resulting from syrinx expansion originating in proximity to the traumatic epicenter. Several pathogenetic factors are associated with this disorder, however, the precise mechanism of the development of PTSM is controversial. Combined anatomical alterations and molecular changes following trauma to the spinal cord and arachnoid participate in the development of this condition. These factors include narrowing or obstruction of the subarachnoid space (SAS), central canal occlusion, myelomalacia, and alterations in intramedullary water permeability. If a patient sustains a SCI with delayed progressive deterioration in neurological function, in association with the MRI appearance of syringomyelia (SM), the diagnosis of PTSM is straightforward. The treatment of PTSM has not undergone any significant changes recently. The surgical treatment of PTSM consists of reconstructing the SAS or shunting fluid away from the syrinx to other locations. The advantages and disadvantages of each procedure will be discussed. With greater understanding of the mechanisms contributing to the development of SM, including advanced diagnostic methods and further advances in the development of artificial dural and shunting tubing, future therapies of PTSM will be more effective and long-lasting. Incorporation of alterations of AQP4 expression provides an intriguing possibility for future treatment of PTSM.

Pathophysiology of primary spinal syringomyelia.

OBJECT: The pathogenesis of syringomyelia in patients with an associated spinal lesion is incompletely understood. The authors hypothesized that in primary spinal syringomyelia, a subarachnoid block effectively shortens the length of the spinal subarachnoid space (SAS), reducing compliance and the ability of the spinal theca to dampen the subarachnoid CSF pressure waves produced by brain expansion during cardiac systole. This creates exaggerated spinal subarachnoid pressure waves during every heartbeat that act on the spinal cord above the block to drive CSF into the spinal cord and create a syrinx. After a syrinx is formed, enlarged subarachnoid pressure waves compress the external surface of the spinal cord, propel the syrinx fluid, and promote syrinx progression. METHODS: To elucidate the pathophysiology, the authors prospectively studied 36 adult patients with spinal lesions obstructing the spinal SAS. Testing before surgery included clinical examination; evaluation of anatomy on T1-weighted MRI; measurement of lumbar and cervical subarachnoid mean and pulse pressures at rest, during Valsalva maneuver, during jugular compression, and after removal of CSF (CSF compliance measurement); and evaluation with CT myelography. During surgery, pressure measurements from the SAS above the level of the lesion and the lumbar intrathecal space below the lesion were obtained, and cardiac-gated ultrasonography was performed. One week after surgery, CT myelography was repeated. Three months after surgery, clinical examination, T1-weighted MRI, and CSF pressure recordings (cervical and lumbar) were repeated. Clinical examination and MRI studies were repeated annually thereafter. Findings in patients were compared with those obtained in a group of 18 healthy individuals who had already undergone T1-weighted MRI, cine MRI, and cervical and lumbar subarachnoid pressure testing. RESULTS: In syringomyelia patients compared with healthy volunteers, cervical subarachnoid pulse pressure was increased (2.7 ± 1.2 vs 1.6 ± 0.6 mm Hg, respectively; p = 0.004), pressure transmission to the thecal sac below the block was reduced, and spinal CSF compliance was decreased. Intraoperative ultrasonography confirmed that pulse pressure waves compressed the outer surface of the spinal cord superior to regions of obstruction of the subarachnoid space. CONCLUSIONS: These findings are consistent with the theory that a spinal subarachnoid block increases spinal subarachnoid pulse pressure above the block, producing a pressure differential across the obstructed segment of the SAS, which results in syrinx formation and progression. These findings are similar to the results of the authors' previous studies that examined the pathophysiology of syringomyelia associated with obstruction of the SAS at the foramen magnum in the Chiari Type I malformation and indicate that a common mechanism, rather than different, separate mechanisms, underlies syrinx formation in these two entities. Clinical trial registration no.: NCT00011245.

The presence of arachnoiditis affects the characteristics of CSF flow in the spinal subarachnoid space: a modelling study.

Syringomyelia is a neurological disorder characterised by high pressure fluid-filled cysts within the spinal cord. As syringomyelia is associated with abnormalities of the central nervous system that obstruct cerebrospinal fluid (CSF) flow, it is thought that changes in CSF dynamics play an important role in its pathogenesis. Using three-dimensional computational models of the spinal subarachnoid space (SAS), this study aims to determine SAS obstructions, such as arachnoiditis, change in CSF dynamics in the SAS. The geometry of the SAS was reconstructed from a series of MRI images. CSF is modelled as an incompressible Newtonian fluid with a dynamic viscosity of 1 mPa s. Three computational models simulated CSF flow in either the unobstructed SAS, or with the SAS obstructed by a porous region simulating dorsal or circumferential arachnoiditis. The permeability of this porous obstruction was varied for the model with dorsal arachnoiditis. The results show that arachnoiditis increases flow resistance in the SAS and this is accompanied by a modest increase in magnitude and/or shift in timing (with respect to the cardiac cycle) of the CSF pressure drop across the region of arachnoiditis. This study suggests that syrinx formation may be related to a change in temporal CSF pulse pressure dynamics.

Spinal subarachnoid space pressure measurements in an in vitro spinal stenosis model: implications on syringomyelia theories.

Full explanation for the pathogenesis of syringomyelia (SM), a neuropathology characterized by the formation of a cystic cavity (syrinx) in the spinal cord (SC), has not yet been provided. It has been hypothesized that abnormal cerebrospinal fluid (CSF) pressure, caused by subarachnoid space (SAS) flow blockage (stenosis), is an underlying cause of syrinx formation and subsequent pain in the patient. However, paucity in detailed in vivo pressure data has made theoretical explanations for the syrinx difficult to reconcile. In order to understand the complex pressure environment, four simplified in vitro models were constructed to have anatomical similarities with post-traumatic SM and Chiari malformation related SM. Experimental geometry and properties were based on in vivo data and incorporated pertinent elements such as a realistic CSF flow waveform, spinal stenosis, syrinx, flexible SC, and flexible spinal column. The presence of a spinal stenosis in the SAS caused peak-to-peak cerebrospinal fluid CSF pressure fluctuations to increase rostral to the stenosis. Pressure with both stenosis and syrinx present was complex. Overall, the interaction of the syrinx and stenosis resulted in a diastolic valve mechanism and rostral tensioning of the SC. In all experiments, the blockage was shown to increase and dissociate SAS pressure, while the axial pressure distribution in the syrinx remained uniform. These results highlight the importance of the properties of the SC and spinal SAS, such as compliance and permeability, and provide data for comparison with computational models. Further research examining the influence of stenosis size and location, and the importance of tissue properties, is warranted.

[Efficacy of subarachnoid space protection in intracranial operation: a report of 156 cases].

OBJECTIVE: To determine the efficacy of subarachnoid space protection in intracranial operation. METHODS: Data collected from 156 consecutive cranial operations, in which subarachnoid space protective technology was prophylacticly used, were analyzed. RESULTS: Fourteen patients had a postoperative fever for more than 1 week and 16 patients who required lumbar puncture to release blood contaminated cerebro-spinal fluid (CSF) or exclude meningitis. All except 3 patients were discharged as expected. No patients had symptomatic vasospasm and hydrocephalus. CONCLUSION: The subarachnoid space protective technology has good effect on preventing postoperative fever and improving the outcome of patients.

Choroid plexus papilloma presenting with cerebrospinal fluid rhinorrhea and otorrhea: case report.

A 52-year-old woman presented with right rhinorrhea and right otorrhea manifesting as aural fullness for 2 years caused by a choroid plexus papilloma in the right cerebellomedullary cistern. Computed tomography and magnetic resonance imaging revealed a well defined lobulated mass at the foramen of Luschka, which extended towards the right cerebellomedullary cistern with slight dilation of the ventricular systems. The tumor was totally resected via a right lateral suboccipital approach. Histological examination revealed a choroid plexus papilloma. Postoperative course was uneventful, just after the operation rhinorrhea ceased completely, and hearing of the right ear dramatically improved. Choroid plexus papillomas rarely cause cerebrospinal fluid (CSF) rhinorrhea. Total removal of the tumor resulted in the cessation of CSF leaks.

Surgical treatment of posttraumatic syringomyelia.

OBJECTIVE: The present study evaluates the effectiveness of 2 surgical procedures, shunting and untethering, for posttraumatic syringomyelia. METHODS: We retrospectively reviewed the medical charts of all surgical patients with posttraumatic syringomyelia in our department. Shunting was performed before 1997; after 1997, we used arachnoidolysis and untethering. RESULTS: Shunting was performed in 15 patients, and 19 patients underwent arachnoidolysis. Statistical analysis found that the 2 groups did not differ in age or initial clinical or radiological presentation. All patients suffered from progressively worsening symptoms. Reconstruction of the subarachnoid space by arachnoidolysis and untethering the cord allowed us to improve or stabilize 94% of our patients. Shunting exposed the patients to a higher rate of clinical recurrence and reoperation. Comparisons between the 2 groups found a significant difference (better results) in favor of arachnoidolysis for the McCormick classification (P = .03), American Spinal Injury Association motor score of the lower extremities (P = .02), and subjective grading (P = .001). There was no significant difference in the evolution of pain or the Vaquero index between the 2 groups; however, a tendency appeared in favor of arachnoidolysis for cyst evolution in regard to the extent of the cyst and the Vaquero index (P = .05). CONCLUSION: Our results confirmed that arachnoidolysis is an effective and safe treatment for posttraumatic syringomyelia. Because the majority of patients were stabilized, we concluded that surgery should be performed as soon as possible in patients with clearly progressing clinical features.

Postural tremor as a manifestation of spontaneous intracranial hypotension.

Spontaneous intracranial hypotension (SIH) is a syndrome caused by low cerebrospinal fluid (CSF) pressure due to leakage of CSF. Clinically, orthostatic headache, neck pain, nausea, emesis, interscapular pain, diplopia, dizziness, changes in hearing, visual blurring and radicular upper extremity symptoms are most frequently observed. We describe a 57-year-old man with SIH who presented with postural tremor. CSF leakage was revealed by cranial MRI. Lumbar puncture identified low CSF pressure and intrathecal gadolinium enhanced MR cisternography showed diffuse CSF leakage in the thoracolumbar region. The patient underwent epidural blood patching, which resulted in complete resolution of postural tremor within 2 months.

Subarachnoid-pleural fistula treated with noninvasive positive pressure ventilation: a two-case report and literature review.

STUDY DESIGN: A report on 2 cases of subarachnoid pleural fistula (SAPF) treated with noninvasive positive pressure ventilation (NPPV). OBJECTIVE: To highlight the efficacy of NPPV in patients with SAPF. SUMMARY OF BACKGROUND DATA: SAPF is a rare but distressing type of cerebrospinal fluid leakage. It is known to be a complication of anterior thoracic spine surgery. The pressure gradient between the subarachnoid space and the pleural cavity maintains the cerebrospinal fluid leakage and precludes the spontaneous closure of the dura. Surgical interventions such as primary repair, patch grafts, muscle flaps, and omental flaps have been advocated. Only limited reports were found with reference to NPPV applied to SAPF. METHODS: Two patients, a 45-year-old woman and a 39-year-old woman, underwent anterior thoracic spine surgery to treat thoracic myelopathy caused by ossification of the posterior longitudinal ligament. After surgery, they developed SAPF due to perforation of the dura during surgery. Placement of thoracostomy tubes and subarachnoid drains had no effect and an NPPV device was applied. RESULTS: During application of the NPPV device, 14 days in the first patient and 5 days in the second patient, the raised intrapleural pressure obstructed the fluid leakage and successfully treated the fistula. No recurrence of SAPF was observed after removal of the NPPV device and the patients avoided surgical interventions. CONCLUSION: SAPF is often resistant to conservative therapies and has been treated in an invasive manner. NPPV should be considered as an alternative before such interventions because it is effective, noninvasive, and safe.

Cerebellar tonsillar herniation after weight loss in a patient with idiopathic intracranial hypertension.

Acquired cerebellar tonsillar herniation is a known complication of lumboperitoneal shunt (LPS) for any indication, including idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri.(1) While the underlying pathophysiology of IIH remains unknown, increasing body mass index is a clear risk factor for the development of IIH. We describe an obese patient with IIH unresponsive to LPS who developed symptoms of intracranial hypotension and cerebellar tonsillar herniation after bariatric surgery and a 50-kg weight loss.