DE3127882A1 - Measurement and recording device for studying and treating hydrocephalus and for monitoring during external drainage of cerebrospinal fluid - Google Patents

Abstract

The object of the invention is to permit pre-operative study of CSF dynamics via a measuring system prior to treatment of a hydrocephalus patient. This entails the patient-specific switching points of the recording device being detected. The measurement and recording device is characterised in that the output signal of the pressure sensor (2) is compared with an adjustable target value in a control system (4). The control circuit (10) implanted for treating hydrocephalus can simultaneously be adjusted to a patient-specific switching point. For investigating the particular CSF dynamics of the patient the control circuit and recording system may be located outside the patient's body. During treatment of hydrocephalus a miniaturised design of the control circuit (10) is implanted which uses electrically triggerable magnetic valves (8) without any controlling characteristics of their own. <IMAGE>

Description

Measuring and deriving device for study and treatment

of the hydrocenhalus.

The invention relates to a measuring and deriving device for study as well as for the treatment of hydrocephalus and for monitoring with external liquor drainage.

in patients with hydrocephalus and increased intracranial pressure, the excess must Cerebrospinal fluid (cerebrospinal fluid) either in any body cavity or drained into the blood via the superior vena cava.

The drainage device usually consists of a brain catheter, which is inserted through a skull bore into the brain cavity to be treated (ventricle) and via a valve to a drain line to the desired body cavity or vein is connected.

The Bbflpß ensures that the excess or blocked liquor cçrebroapinalis is removed from the ventricular space and directed into this cavity. # to control the drainage process is usually a with a; valve provided with a certain closing pressure is used.

The pressure of the cerebrospinal fluid in the lumbar area as well in the brain ventricles has a constant value which is within certain limits holds. In the literature, the formation of cerebral water is given as approx. 500 ml / day with normal ventricular pressure between 0 and 200 mm H20 column.

When treating fiydrocephalus, a reduced pressure should now be used of the brain fluid can be produced with the aid of the drainage device. Of the The operating pressure of the valve in the drainage device is equal to that desired liquor pressure. The outflow of cerebral fluid from the ventricles takes place as long as the liquor pressure is above the switching pressure of the valve. ser The low CSF pressure aimed for during treatment is below the cerebral blood pressure.

This increases the surface loading of the brain tissue by the slut as the opposing force which is produced by the cerebrospinal fluid. The result is a reduction in the size of the ventricles. For the desired liquor pressure however, is different depending on the Tyr and behavior of the patient, In addition it must be adjustable within narrow limits, if not by unwanted Low or negative pressure subdural bleeding, cerebral Odewe, hematomas, etc. occur It is known to meet these demands drainage devices for draining excess cerebrospinal fluid with the help of a laid under the skin to create drainage line in which a valve is arranged. The valve will a transcutaneously adjustable proportional pressure regulator assigned to the as negel variable the CSF flowing through a ventricle catheter acts.

ves further is in DOS 23 40 617 a device for discharge of cerebrospinal fluid from the brain cavities and a suitable valve described. in this case, a pretensioning device is provided which the valve tried to push into the closed position. you mindirect to control the bias has a feeler that is directly on the brain or on the meninges and responds to the pressure exerted by the brain.

In another known valve device for ventricular manifold systems (DOS 26 24 496) is a ventricular catheter and implantable drainage line for drainage of cerebrospinal fluid from a ventricle is used. in the drain line is a first one-way valve with a relatively low boom pressure and a second one zinwegventil provided with a preferably higher threshold pressure.

v the previously known discharge devices available for the treatment of hydrocephalus there are valves in the bricks that control the Only allow cerebrospinal fluid to pass through if it has reached a certain pathological value. zo there are so-called high-pressure, medium-pressure and low-pressure valves.

vie operation of the valves is controlled purely mechanically and depends on the valve properties.

well-known valve systems usually have an indefinite one Closure pressure, which is an adaptation to the patient-specific CSF dynamics not possible in rydrocephalus. In addition, the phenomenon can be observed that the force damaging the brain (too high pressure of the cerebrospinal fluid) not just a puncture of the too high CSF pressure, but rather when it is strong enlarged ventricles, the product of the large ventricular area and normal ventricular pressure to lead to pathological situations.

The invention is based on the object, prior to the treatment of hydrocephalus #patients to carry out a pre-operative study of the CSF dynamics using an xess system. this will be on the special ratient situations coordinated Switching points found through measurement that enable optimal treatment.

The Keß and Teglersystem should be outside the body of the patient. In addition, the fiction, contemporary measuring and derivation device work reliably without hindrance or blockage with as little maintenance as possible and a minimum of moving parts such as ~. an additional rinsing pump. bur treatment should be the functionally and structurally identical measuring and drainage system (without the Counting device) to be implanted into the patient.

According to the invention, fleece task is achieved in that the output signal of the pressure transducer t2) in a Ziegler # 4) compared with an adjustable setpoint will. The control circuit (10) implanted for the treatment of hydrocephalus is open a patient-specific switching point can be set. In examining this The patient's own CSF dynamics are the control circuit and the drainage system outside the patient's body.

During the hydrocephalus treatment period, a miniaturized one Execution of the control loop (10) implanted in the patient. In addition, will an electrically controllable solenoid valve (8) without its own control characteristic is used.

With certain measurements it can be advantageous to use the pressure transducer (2) to be assigned to the catheter (1) so that the pressure sensor is during the measurement is located at the catheter tip in the ventricle space (6). The implanted control loop (10) can be advantageous with the necessary power supply through an integrated voltage supplier Control voltage are supplied.

In addition, the control voltage is also supplied by an external voltage source available. To determine the patient-specific pressure pairs, the preoperative Examination measured by means of an external recording device (5).

In a further embodiment of the invention, the derivation device the control loop (10) intended for implantation, the controller (4) and the Valve (8) and the pressure sensor (2) in a common one of the discharge line (3) housed associated housing. The valve (8) functions at the same time as a check valve and has the same inside width as the catheter (1). This increases the risk of clogging due to particles washed out in the CSF flow greatly diminished.

The implanted controller (4) can be external depending on the type of design abandoned electrical and / or magnetic impulses Further desired switching points can be changed 0 A simplified embodiment of the The device according to the invention includes a control line leading to the outside by means of which externally given impulses enable the changeover to further switching points An embodiment of the invention is shown in the drawing and is briefly described below. They show: Figure 1s measurement and Drainage device for studying hydrocephalus with extracorporeal drainage and electrically controlled valve with adjustable setpoint.

Figure 2: Implanted, miniaturized version of the measuring and recording device for the treatment of hydrocephalus Figure 3: Section through the miniaturized control circuit (10) with catheter (1) and drainage line (3).

The catheter (1) inserted into the cerebral ventricle (6) has in special cases the pressure sensor (2) at its end point. As a rule, however, this is the case Pressure sensor (2) outside the Skull. Via the catheter (1) the so-called cerebrospinal fluid flows to the control circuit (10) * In the case of the implanted Version is controlled via the pressure sensor (2) of the regulator (4), which according to the previously measured patient-specific switching point, the solenoid valve (8) electrically controls and actuates. The cerebrospinal fluid is transferred to the atrium and abdomen via the drain (3) etc. forwarded. The external registration device (q) shown in FIG. 1 is used for Preoperative study of liquor dynamics in hydrocephalus patients. With the preoperative The cerebrospinal fluid is measured from the ventricular catheter shown (1) or from a needle (not shown) derived and fed to the external pressure sensor (2). the miniaturized version of the measuring and recording device is placed between the skullcap (7) and the scalp (9).

This arrangement of the measuring and deriving device is for the Patients guaranteed the greatest possible freedom of movement.

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Claims (12)

S C H U T Z A N S P R Ü C H E 1. Measuring and deriving device for Study as well as for the treatment of hydrocephalus and for monitoring with external CSF drainage d a d u r c h e k e n n n z ei c h n e t, a) that the output signal of the pressure transducer t2) is compared in a bowler (4) with an adjustable setpoint. b) that the control circuit implanted for the treatment of liydrocephalus (10) is set to a patient-specific switching point. c) that when examining the patient's own CSF dynamics Control circuit and lead system are located outside the patient's body. d) that a miniaturized one during the treatment period of hydrocephalus Execution of the control loop t10) is implanted. e) that electrically controllable solenoid valves (8) without their own control characteristics to be used. 2. Measuring and deriving device according to claim 1, characterized in that that the pressure sensor (2) is integrated into the catheter (1) and yourself is located in the ventricular space (6) during the measurement. 3. Xeß- and discharge device according to claim 1 and / or 2 d a d u r c h e k e n n n e i c h n e t that the implanted control loop (10) is through an integrated voltage supplier internally with the necessary control voltage is supplied. 4. Sitting and draining device according to one or more of the claims 1 to 3 d a d u r c h e k e n n n z e i c h n e t that the implanted control loop t10) is externally supplied with control voltage. 5. Measuring and deriving device according to one or more of the claims 1 to 4 d a d u r c h e k e n n n z e i c h n e t that before the treatment of hydrocephalus the patient-specific switching point using the external recording device (5) is measured. 6 measuring and deriving device according to one or more of the claims 1 to 5 d a d u r c h e k e n n n z e i c h n e t that valves t8) - be used with catheter-like clear width, which obstructs the urinary fluid path impede. 7. Measuring and deriving device according to one or more of the claims 1 to 6 d a d u r c h e k e n n n z e i c h n e t that the valve (8) used at the same time acts as a check valve. 8. Measuring and deriving device according to one or more of the claims 1 to 7 d a d u r c h e k e n n n e i c h n e t that with the implanted control loop (10) controller k4), valve (8) and pressure collector t2) in a common drain line (3) associated housing are housed. 9. Measuring and deriving device according to one or more of the claims 1 to 8 d a d u r c h g e k e n n n n e i c h n e t that the implanted controller (4) by externally given magnetic or electrical impulses to further switching points is adjustable, 10. Measuring and deriving device according to one or several of claims 1 to 9 d a d u r c h g e k e n nze i c h n e t that the implanted controller (4) via a control line through externally given electrical Pulse is switchable. 11. Measuring and deriving device according to one or more of the claims 1 to 10 d a d u r c h g e k e n n n z e i c h n e t that the pressure sensor (2) is outside of the ventricle (6) is at the outer end of the catheter (1). 12. Measuring and deriving device according to one or more of the claims 1 to 11 d a d u r c h e k e n n n z e i c h n e t that in patients who are still have significant liquor absorption, the control circuit (10) on one upper and lower patient-specific switching point is adjustable.