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Sotelo J. The hydrokinetic parameters of shunts for hydrocephalus might be inadequate. Surg Neurol Int 2012; 3:40. [PMID: 22530174 PMCID: PMC3326986 DOI: 10.4103/2152-7806.94292] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 02/02/2012] [Indexed: 11/04/2022] Open
Abstract
Long-term treatment of hydrocephalus continues to be dismal. Shunting is the neurosurgical procedure more frequently associated with complications, which are mostly related with dysfunctions of the shunting device, rather than to mishaps of the rather simple surgical procedure. Overdrainage and underdrainage are the most common dysfunctions; of them, overdrainage is a conspicuous companion of most devices. Even when literally hundreds of different models have been proposed, developed, and tested, overdrainage has plagued all shunts for the last 60 years. Several investigations have demonstrated that changes in the posture of the subject induce unavoidable and drastic differences of intraventricular hydrokinetic pressure and cerebrospinal fluid (CSF) drainage through the shunt. Of all the parameters that participate in the pathophysiology of hydrocephalus, the only invariable one is cerebrospinal fluid production at a constant rate of approximately 0.35 ml/min. However, this feature has not been considered in the design of currently available shunts. Our experimental and clinical studies have shown that a simple shunt, whose drainage capacity complies with this unique parameter, would prevent most complications of shunting for hydrocephalus.
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Affiliation(s)
- Julio Sotelo
- Emeritus Investigator, National Institute of Neurology and Neurosurgery, Insurgentes Sur 3877, Mexico City, 14269, Mexico
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Mom T, Gilain L, Avan P. Effects of glycerol intake and body tilt on otoacoustic emissions reflect labyrinthine pressure changes in Menière's disease. Hear Res 2009; 250:38-45. [PMID: 19450433 DOI: 10.1016/j.heares.2009.01.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 01/26/2009] [Accepted: 01/27/2009] [Indexed: 10/21/2022]
Abstract
It is known that by influencing stapes stiffness thus the ear's impedance, changes in intracranial and intralabyrinthine pressure induce a characteristic phase shift in otoacoustic emissions (OAE) around 1 kHz in human ears. Thus, if the regulation of pressure in intralabyrinthine compartments were abnormal in Menière patients, OAEs might help detect it. Body tilt, which acts on intracranial pressure, and administration of an osmotically active substance provide two simple ways of manipulating intralabyrinthine pressure. Here, 14 patients with typical signs of an attack of unilateral endolymphatic hydrops were submitted to postural changes and a glycerol test. Their OAEs initially collected in upright position served as references, then OAEs were measured in supine position, and back to the upright posture one and 3h after glycerol intake. Twenty control subjects were also tested for body tilt. The main effect of body tilt and glycerol was a phase rotation of OAEs peaking around 1 kHz. Its frequency dependence matched the one due to a pressure-related change in stapes or basilar membrane stiffness predicted by the ear model of Zwislocki (1962). The average glycerol-induced phase shifts were similar in size in Menière vs. asymptomatic ear and audiometric thresholds were stable after glycerol intake in line with the model predicting little change in the magnitude of the transfer function. These data support a simple conductive pressure-related mechanism explaining the action of glycerol on inner ear responses. The fact that the mean postural shift was three times larger in Menière than asymptomatic and control ears suggests an additional effect in allegedly hydropic ears.
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Affiliation(s)
- Thierry Mom
- Laboratory of Sensory Biophysics, School of Medicine, University of Auvergne, 28, Place Henri Dunant, 63000 Clermont-Ferrand, France
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Chomicki A, Sakka L, Avan P, Khalil T, Lemaire JJ, Chazal J. Dérivation du liquide cérébrospinal avec valve: ses conséquences sur la biomécanique de l'oreille interne chez les patients atteints d'hydrocéphalie chronique de l'adulte. Neurochirurgie 2007; 53:265-71. [PMID: 17559890 DOI: 10.1016/j.neuchi.2007.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Accepted: 04/10/2007] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND PURPOSE Patients suffering from hydrocephalus are often treated by the surgical placement of a shunt, directing the excess of cerebrospinal fluid towards another body compartment. However, the degree of clinical improvement is variable and the dynamics of cerebrospinal fluid pressure in shunted hydrocephalus is poorly understood. A recently developed noninvasive technique makes it possible to follow pressure variations: it is based on otoacoustic emissions, sounds naturally emitted by the cochlea and routinely detected in audiology. When cerebrospinal fluid pressure changes, emissions undergo a phase shift while crossing the oval window. The goal of this work is to study how this shift is affected by shunt placement. METHOD Otoacoustic emissions were recorded repeatedly in 22 adult patients who suffered from chronic hydrocephalus. Their phase shifts were measured, in sitting and recumbent positions, before and after surgical placement of a ventriculo-peritoneal shunt (Sophysa SM8). RESULTS Postural shift in normal subjects is a phase lead, and this outcome was found in 17 of 22 patients preoperatively. After shunt placement, the postural effect became a phase lag in 18 patients of 20. In a given posture, sitting or recumbent, phase shifts changed from pre to postoperative measurements in a systematic manner. CONCLUSION Otoacoustic emissions respond in a characteristic way to posture changes in normal adults, and having received a shunt for chronic hydrocephalus reverses the effect, presumably in relation to the existence of a "vacuum" in the inner ear.
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Affiliation(s)
- A Chomicki
- Laboratoire de biophysique sensorielle (EA 2667), faculté de médecine, université d'Auvergne, CHU de Clermont-Ferrand, PO Box 38, 63000 Clermont-Ferrand, France
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Meier U, Kiefer M, Neumann U, Lemcke J. On the optimal opening pressure of hydrostatic valves in cases of idiopathic normal-pressure hydrocephalus: a prospective randomized study with 123 patients. ACTA NEUROCHIRURGICA. SUPPLEMENT 2006; 96:358-63. [PMID: 16671485 DOI: 10.1007/3-211-30714-1_74] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Does the opening pressure of hydrostatic shunts influence the clinical outcome for patients suffering from idiopathic normal-pressure hydrocephalus (NPH)? Between September 1997 and January 2003, 123 patients with idiopathic NPH were surgically treated by implanting a hydrostatic shunt at the Departments of Neurosurgery of the Unfallkrankenhaus Berlin and the University Homburg/Saar. As part of a prospective randomized study, all patients were examined preoperatively, postoperatively, and 1 year after the intervention. Forty-three percent of the patients showed a very good outcome, 25% good outcome, 20% fair outcome, and 12% poor outcome 1 year after the shunt implantation. Patients treated with an opening pressure rating of 50 mmH2O in the low-pressure stage of the gravitational valve showed a better outcome than those with an opening pressure of 100 or 130 mmH2O. According to present knowledge, hydrostatic shunts with an opening pressure of 50 mmH2O for the low-pressure stage are the best option for patients with idiopathic NPH. Due to the prompt switching function when the patient changes posture (lying down, standing, sitting, slanting etc.), the Miethke gravity-assisted valve (GAV) is more suitable in such cases than the Miethke Dual-Switch valve (DSV).
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Affiliation(s)
- U Meier
- Department of Neurosurgery, Unfallkrankenhaus Berlin, Berlin, Germany.
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Lee MC, Yamini B, Frim DM. Pseudotumor cerebri patients with shunts from the cisterna magna: clinical course and telemetric intracranial pressure data. Neurosurgery 2005; 55:1094-9. [PMID: 15509316 DOI: 10.1227/01.neu.0000141314.28782.10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Accepted: 06/11/2004] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Shunting of cerebrospinal fluid (CSF) to an extracranial site is the mainstay of treatment of absorptive hydrocephalus and pseudotumor cerebri. On occasion, both lateral ventricles and the lumbar space become unsuitable for placement of a functioning CSF drainage catheter. We have encountered several such patients and describe our strategy of shunting from the cisterna magna to the pleural space or cardiac atrium. METHODS We report a retrospective review of the clinical course of five patients with cisternal shunts and intracranial pressure telemonitoring devices. RESULTS Cisternal shunting was able to successfully drain CSF to a normal pressure in all five patients. CSF pressure data collected from those patients indicate that the CSF pressure dynamics in cisternal shunts is similar to that of ventricular shunts. However, the cisternal shunting and subsequent high revision rate did result in a significant number of complications and two shunt infections. CONCLUSION Shunting CSF from the cisterna magna in the absence of another suitable drainage site does result in acceptable reduction of elevated intracranial pressure. However, the technique is associated with a high complication rate that may reflect the population of patients in whom this technique is required.
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Affiliation(s)
- Max C Lee
- Section of Neurosurgery, Department of Surgery, University of Chicago Hospitals and Pritzker School of Medicine, Chicago, Illinois, USA
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On the Optimal Opening Pressure of Hydrostatic Valves in Cases of Idiopathic Normal-Pressure Hydrocephalus. ACTA ACUST UNITED AC 2005. [DOI: 10.1097/01.wnq.0000162225.66254.95] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
Telemonitoring, is defined as the use of information technology to monitor patients at a distance. This literature review suggests that the most promising applications for telemonitoring is for chronic illnesses such as cardiopulmonary disease, asthma, and heart failure in the home. Fetal heart rate monitoring and infant cardiopulmonary functions have also been monitored at a distance, as well as coagulation, or the level of activity of elderly people, assessed by the intelligent home monitoring devices. Hospitals, clinics, and prisons all have used telemonitoring, as have ambulances equipped with systems connected to the receiving hospital. Telemonitoring allows reduction of chronic disease complications thanks to a better follow-up; provides health care services without using hospital beds; and reduces patient travel, time off from work, and overall costs. Several systems have proven to be cost effective. Telemonitoring is also a way of responding to the new needs of home care in an ageing population. Real-time monitoring of patients in ambulances reduces the time to initiate treatment and allows the emergency crew to be better prepared. The obstacles to telemonitoring development include the initial costs of systems, physician licensing, and reimbursement. In the future, virtual reality, immersive environments, haptic feedback and nanotechnology promise new ways in improving the capabilities of telemonitoring.
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Affiliation(s)
- Stephane Meystre
- Department of Medical Informatics, University of Utah, Salt Lake City, Utah 84132-2913, USA.
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Sotelo J, Arriada N, López MA. Ventriculoperitoneal shunt of continuous flow vs valvular shunt for treatment of hydrocephalus in adults. ACTA ACUST UNITED AC 2005; 63:197-203; discussion 203. [PMID: 15734497 DOI: 10.1016/j.surneu.2004.07.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Accepted: 07/29/2004] [Indexed: 10/25/2022]
Abstract
BACKGROUND Shunting for hydrocephalus is the neurosurgical procedure most frequently associated with long-term complications. We developed an alternative to valvular shunts based on a simple shunt procedure whose functioning depends on a peritoneal catheter with a highly precise cross-sectional internal diameter of 0.51 mm. Preliminary studies have shown that the shunt of continuous flow (SCF) is superior to valvular shunts for the treatment of hydrocephalus in adults. Here, we show the long-term performance of the SCF in adult patients with hydrocephalus secondary to a comprehensive variety of neurological disorders. METHODS In a 5-year period, ventriculoperitoneal shunting was performed on 307 patients with hydrocephalus; 114 of them were treated with the SCF and 193 controls were treated with a conventional valvular shunt. Patients were followed from 1 to 5 years after surgery; endpoint observation was considered at surgical reintervention because of shunt failure. RESULTS At the end of the observation period (44 +/- 17 months), the failure rate of the shunting device was 14% for the SCF and 46% for controls (P < .0002). Shunt endurance was 88% in patients with SCF and 60% in controls. Along the study, signs of overdrainage developed in 40% of patients treated with valvular shunt, but they were not observed in patients with SCF. CONCLUSIONS The design of the SCF was calculated according to the mean rates of cerebrospinal fluid production; it takes simultaneous advantage of the intraventricular pressure and the siphon effect and complies with the principle of uninterrupted flow, maintaining a fair equilibrium that prevents under- and overdrainage. The SCF is a simple, inexpensive, and effective treatment for hydrocephalus in adults.
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Affiliation(s)
- Julio Sotelo
- Divisions of Research and Neurosurgery, National Institute of Neurology and Neurosurgery of Mexico, CP 14269 Mexico City, Mexico.
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10
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Meier U. [Gravity valves for idiopathic normal pressure hydrocephalus. A Prospective study of 60 patients]. DER NERVENARZT 2004; 75:577-83. [PMID: 15156286 DOI: 10.1007/s00115-004-1695-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Are hydrostatic valves superior to conventional differential pressure shunts in patients with normal- pressure hydrocephalus, with regard to the postoperative results of treatment and possible complications? METHODS From September 1997 to January 2002, 60 patients with idiopathic normal-pressure hydrocephalus were treated by surgical implantation of a hydrostatic valve (Miethke dual-switch valve) at the Unfallkrankenhaus Berlin. RESULTS One year after the shunt operation, the clinical picture was very good for 33% of the patients, good for 33%, satisfactory for 17%, and poor for 17%. At 20%, the rate of postoperative complications (catheter dislocations, valve infections, underdrainage and overdrainage) is still relatively high. The opening pressure of the Miethke dual-switch valve did not correlate with the postoperative results of treatment. CONCLUSION According to our experience, hydrostatic Miethke dual-switch valves are superior to conventional differential pressure shunts without an additional gravity unit, especially with regard to the treatment of patients with idiopathic normal -pressure hydrocephalus, concerning both the postoperative results of the treatment and the incidence of possible complications. With differentiated diagnosis and therapy, a clinical improvement can be achieved for 83% of such patients.
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Affiliation(s)
- U Meier
- Klinik für Neurochirurgie, Unfallkrankenhaus Berlin.
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Tsunoda A, Ebato M, Maruki C, Ikeya F. Clinical Experience of a Dual Switch Valve in the Management of Hydrocephalus Post-operative Changes in Ventricular Size and Intra-ventricular Pressure. ACTA ACUST UNITED AC 2002. [DOI: 10.7887/jcns.11.592] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Akira Tsunoda
- Department of Neurosurgery, Koshigaya Municipal Hospital
| | | | | | - Furitsu Ikeya
- Department of Neurosurgery, Koshigaya Municipal Hospital
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Affiliation(s)
- P Chumas
- Departments of Neurosurgery and Paediatric Neurology, Division of Paediatric Neurosciences Leeds General Infirmary, Leeds LS1 3EX, UK
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Lundkvist B, Eklund A, Kristensen B, Fagerlund M, Koskinen LO, Malm J. Cerebrospinal fluid hydrodynamics after placement of a shunt with an antisiphon device: a long-term study. J Neurosurg 2001; 94:750-6. [PMID: 11354406 DOI: 10.3171/jns.2001.94.5.0750] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object. Few studies have been performed to investigate the cerebrospinal fluid (CSF) hydrodynamic profile in patients with idiopathic adult hydrocephalus syndrome (IAHS) before and after shunt implantation. The authors compared the in vivo CSF hydrodynamic properties, including the degree of gravity-induced CSF flow, of a shunt with an antisiphon device with a standard shunt.
Methods. Twelve patients with IAHS underwent insertion of shunts with Delta valves. Clinical testing, magnetic resonance imaging, and CSF hydrodynamic investigations were conducted with intracranial pressure (ICP), gravity effect, and pressure—flow curve of the shunt estimated at baseline and at 3 and 12 months postoperatively. No shunt was revised.
Despite postoperative clinical improvement in all patients who received Delta valves, the mean ICP was only moderately reduced (mean decrease at 3 months 0.3 kPa [p = 0.02], at 12 months 0.2 kPa [not significant]). Patients with the greatest increase in ICP preoperatively had the most pronounced decrease postoperatively. The hydrostatic effect of the Delta valves was significantly lower than with the Hakim shunts (0.1–0.2 kPa compared with 0.6 kPa). The increased conductance (that is, lowered resistance) was up to 14 times higher with the Delta valves compared with preoperative levels.
Conclusions. The function of a CSF shunt may be more complicated than previously thought; the subcutaneous pressure acting on the antisiphon device can modify the shunt characteristics. A compensatory increase in CSF production may counteract the increased outflow through the shunt. The improved CSF outflow conductance may increase the intracranial compliance and thereby dampen a pathological ICP waveform.
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Affiliation(s)
- B Lundkvist
- Department of Clinical Neuroscience, University of Umeå, Sweden.
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