Method of treating hydrocephalus

Abstract

This disclosure relates to a catheter and method for its use to establish a connection between the cerebral ventricles and the proximal segment of a ligated neck vein for treating hydrocephalus. This method for shunting the cerebrospinal fluid (CSF) to the venous circulation prevents blood from coming into contact with the shunt tube and prevents a syphonage force from developing when the patient assumes the upright position. The catheter consists of a tubing of soft tissue-compatible material and is provided with a simple check valve to prevent reflux of blood. It has a side tube and it is also provided with means for: 1) easy insertion into the ventricle; 2) protection of the intake apertures; 3) watertight closure of the dura mater around it; 4) resistance to kinking; 5) provision of an available extra length of 5 cms; and 6) resistance to being pulled out of the neck vein due to movements of the head and neck.

Description

This invention relates generally to the surgical arts, and more particularly to a method and apparatus for treating hydrocephalus by establishing a ventricle venous shunt between the lateral ventricle and the proximal portion of a ligated neck vein.

BACKGROUND OF INVENTION

At the present time, there are several valve systems to provide ventriculo-atrial shunts to drain CSF from the ventricles of the brain into the venous blood stream. Examples of these systems are: U.S. Pat. No. 2,969,066 (Holter et al,); U.S. Pat. No. 3,020,913 (Hyer-Pudenz); and U.S. Pat. No. 3,288,142 (Hakim).

In treating hydrocephalus using one of these valve systems a catheter is thrust into the ventricles of the brain in order to drain unwanted fluid therefrom, and is then led through the jugular vein into the heart so that the fluid from the ventricles enters the blood stream and is disposed of by the process of purification of the blood.

Two main disadvantages encountered with conventional shunt systems are:

1. THE DEVELOPMENT OF A SYPHONAGE FORCE WHENEVER THE PATIENT ASSUMES THE UPRIGHT POSITION. This force corresponds to the height of the CSF column in the shunting catheter and eventually causes excessive ventricular drainage which may lead to the development of intracranial haemorrhage and/or collapse of the cerebral ventricles increasing the chances of blockage of the ventricular end of the shunting catheter;

2. THE SHUNTING CATHETER WHICH LIES DIRECTLY IN THE BLOOD STREAM ACTS AS A FOREIGN BODY AND MAY EXCITE BLOOD CLOTTING, VENOUS THROMBOSIS AND EMBOLIC COMPLICATIONS.

Therefore, as disclosed in co-pending application Ser. No. 316,995, the purpose of the shunt system and the catheter of this invention is in general to avoid all the above difficulties and complications by providing means for treating hydrocephalus by using the catheter of this invention to establish a connection between the cerebral ventricles and the proximal segment of a ligated neck vein, e.g., the external jugular vein (EJV) or the common facial vein (CFV).

In the aforementioned co-pending application Ser. No. 316,995 it is disclosed that the reason for the reflux of blood into the venous end of a non-valved shunting tube is the fact that there is a reduction in the suction effect exerted on the CSF caused by the running blood in the veins during periods of high intrathoracic pressure, as compared with the suction effect during periods of normal intrathoracic pressure. Accordingly, a catheter and method for its use was disclosed which could be inserted into the vein in such a way as to prevent the suction effect of the running blood from exerting its effect on the CSF so that the blood would not regurgitate into the tube during periods of high intrathoracic pressure. This method of establishing the ventricle venous connection commprised inserting the ventricle end of the catheter into the lateral ventricle such that no CSF could leak from the dural hole made for the tube insertion into the ventricle, and the open venous end of the tube was to be inserted into the proximal segment of a ligated neck vein against the direction of blood flow. The catheter disclosed in the instant application represents an improvement over the catheter as disclosed in the aforementioned co-pending application. Moreover, the instant application includes further details and elaboration of the method disclosed in the aforementioned co-pending application.

Accordingly, it is a primary object of this invention to provide a method for establishing a ventriculo venous (VV) connection to the proximal segment of a ligated neck vein which will avoid most of the difficulties and complications encountered in treating hydrocephalus by the conventional ventriculo-atrial drainage systems.

More particularly, it is an object of this invention to provide a catheter which will facilitate establishing the aforementioned VV connection.

Another object of this invention is to provide a catheter made of tissue-compatible material having means for easy insertion into the cerebral ventricle through a small dural hole.

Another object of this invention is to provide a catheter as abovedescribed having means for protection of the drainage apertures in the wall of the catheter tubing at its ventricular end.

Still another object of this invention is to provide a catheter having means which will facilitate a watertight closure of the dura mater around the catheter.

Yet another object of this invention is to provide a catheter as above described having means for introducing a stylet therein to provide an axial force for inserting the catheter into the ventricle.

A further object of this invention is to provide a catheter as above-described having means for recording pressures in the ventricles and in the venous side of the VV connection.

Still another object of this invention is to provide a catheter as above-described having means for monitoring the patency of the shunt system provided by the VV connection.

Another object of this invention is to provide a catheter as abovedescribed having means for prevention of reflux of blood therein.

Another object of this invention is to provide a catheter as above-described having the provision of an available extra 5 cms to the length of the catheter which will accommodate variations in the length of body segment bridged by the catheter.

A further object of this invention is to provide a catheter as above-described having resistance to kinking at the sites of curves in the course of the catheter as well as resistance to being pulled out of the vein due to movements of the head and neck.

With the above and other objects in view that may hereinafter become apparent, the nature of the invention may be more clearly understood by reference to the several views illustrated in the accompanying drawings, the following detailed description thereof, and the appended claimed subject matter:

IN THE DRAWINGS

FIG. 1 is a schematic illustration of the head and neck of an individual, and illustrates the ventriculo venous shunt (VV) of this invention showing the catheter in its place to establish the connection between the cerebral ventricle and the proximal segment of a ligated EJV;

FIG. 2 is a plan view of the catheter of this invention, having portions thereof cut away for clarity to illustrate internal portions thereof;

FIG. 3 is a plan view of a stylet which may be utilized to insert the catheter illustrated in FIG. 2.

Referring now to the drawings in detail, there is illustrated in FIG. 2 a catheter made of soft silicone rubber or any other tissue-compatible material and has a simple, unidirectional check valve (V) incorporated near its middle. For purposes of description, the catheter can be divided into a ventricular segment and a venous segment between which the check valve (V) is incorporated. The ventricular segment extends from the ventricular tip to the check valve and comprises the following: (1) a ventricular tip (A) which is firm blind pointed with a depression (D) on its inside for lodging a stylet (S), FIG. 3, which is used to provide an axial force for inserting the catheter into the ventricle. This arrangement keeps the pointed tip pointing forwards and permits its easy insertion through a tiny dural hole; (2) intake apertures (H) in the wall of the first two centimeters of the ventricular end of the catheter which permit the flow of CSF from the ventricle into the catheter; (3) soft silicone rubber flanges (F1) attached to the catheter wall and projecting between the apertures (H) protect them by bending and closing them during insertion of the catheter into the ventricle and reopen inside the ventricle thereby keeping the apertures away from the wall of the ventricle and from the choroid plexus; (4) a single soft silicone rubber flange (F2) is attached to the catheter at a distance approximately 10 cms from the ventricular tip. The flange (F2) marks the extent of catheter to be inserted through the dural hole and is also used for obtaining a watertight closure of the dura mater around the catheter either by using Histacryl to stick the flange to the dura mater or by suturing it. This flange (F2) can be made of a larger diameter than the flanges (F1) protecting the apertures (H); (5) a few centimeters beyond the flange (F2) a side tube (T) projects from the main catheter at an angle of about 45.degree.. The side tube is of the same thickness and bore as the rest of the catheter and measures about 4 cms in length. It is used as a means for inserting the stylet (S), FIG. 3, into the ventricular segment of the catheter. It can also be connected to a manometer to record the pressure in the ventricle or in the vein side of the connection during the operation. The side tube (T) is tied after the satisfactory establishment of the VV connection and can be used later to check the patency of the shunt system if such a step is ever needed; (6) two strong side flanges (F3) with holes are attached to the catheter at the point of its junction with the side tube. The flanges (F3) are used for fixing the catheter to the periosteum by sutures (FIG. 1, Lig. 3).

The simple check valve (V) which separates the ventricular from the venous segment of the catheter lies a few centimeters beyond the side tube (T). This valve prevents reflux of blood into the catheter but it has nothing to do with the regulation of the intraventricular pressure (IVP).

The venous segment of the tube extends from the check valve till the venous end and consists of: (1) the venous end of the catheter which includes a bulbous portion (G) so as to prevent its slipping out from the neck vein due to movements of the neck. The outside diameter of the bulbous venous end (G) of the catheter is approximately double that of the main portion of the catheter and therefore it is unlikely to slip out from the vein when a ligature is tied around the vein to hold the tube inside it; (2) a kink-proof segment which extends from the bulbous venous end for a distance of about 15 cms. A spiral wire (Sp.W) is incorporated into the venous portion of the catheter to prevent kinking and occlusion of the catheter at the point where it curves up to enter into the tied neck vein; (3) the other half of the venous segment has an expansible telescoping segment (TS) which can provide an extension of the tube an extra length of about 5 cms. Such a length is needed to allow for variations in the length of body segment bridged by the shunting catheter as occurs during movements of the head or due to an increase in length of the individual.

Exemplary dimensions of the elements of this invention may be as follows: Its length may be approximately 37 cms, the outside diameter of the tubing may be approximately 2.2 mms, the lumen may be approximately 1 mm. The distance between the ventricular tip and the flange (F2 in FIG. 2) may be approximately 10 cms, from the flange (F2) to the side tube (T) may be approximately 3 cms and from the side tube to the valve (V) may be approximately 3 cms. The segment of tube between the check valve (V) and the bulbous venous end (G) of the catheter may be approximately 20 cms. A spiral wire (Sp.W) or any anti-kinking system is incorporated in the 15 cms of tubing next to the bulbous venous end (G) while in the remaining 10 cms of tubing between the end of the spiral wire and the check valve the telescoping segment (TS) is incorporated into the catheter. Of course, depending on the intended use and the age of the patient, these dimensions and arrangements can be varied at will.

The theoretical basis for the suggested ventriculo venous (VV) connection (FIG. 1) is as follows: If a neck vein, e.g., the EJV, is tied (Lig. 1 in FIG. 1) above the valve in its lower end, the pressure in the proximal segment of the vein rises to about +8 to 9 cms saline. If the catheter of this invention (FIG. 2) is used to establish a connection between the cerebral ventricle and the proximal segment of the ligated EJV provided that CSF loss or leakage is not allowed to occur, a closed system will be established one side of which will be the cerebral ventricles and the other side will be the vein segment BC in FIG. 1. Since the pressure in the hydrocephalic ventricles is much higher than the pressure in the vein segment BC, the CSF will flow from the cerebral ventricle, through the shunt tube and through the vein segment BC, washing the blood away from it and converting it into an extension to the shunt tube. The CSF enters the venous circulation at point C via the tributaries of the tied vein. The flow of CSF continues until a state of equilibrium between the pressures in the cerebral ventricles and in the vein segment BC takes place, and the CSF will flow thereafter into the venous circulation at a rate corresponding to the rate of its formation.

Establishing the VV connection in this way fulfills the following advantages: (1) the vein segment BC will be converted into an extension to the shunt tube connecting the venous end of the catheter (at point B) to the circulating venous blood at point C. This vein segment will be full of CSF which acts as a barrier preventing contact between the catheter and the circulating blood; (2) the higher pressure created in the proximal segment of the tied vein provides a resistance to the flow of CSF and maintains the intraventricular pressure (IVP) at a level higher than the pressure in the vein segment by an amount that will depend on the rate of CSF formation. The average IVP after establishing the connection is around +12 cms saline which is within normal limits. This means that no excessive ventricular decompression takes place; (3) reflux of blood into the catheter cannot occur because of a simple check valve (V in FIGS. 1 and 2) incorporated into it. Dissimilar from other valves used in conventional ventriculo-atrial catheters, the valve in this invention has nothing to do with the regulation of the IVP, its only job is to prevent reflux of blood; (4) a syphonage effect does not occur when the patient assumes the upright position because of the hydrostatic pressure of the blood in the veins of the head and neck.

METHODS OF ESTABLISHING THE VV CONNECTION

The ventricular end of the catheter is inserted into the cerebral ventricle via a small hole in the dura mater which is exposed through a posterior temporal burr hole. The stylet (S), which is approximately 25 cms long wire of a thickness less than the bore of the catheter (approximately 0.5mm), is introduced via the side tube and passed into the ventricular segment of the catheter to lodge in the depression (D) on the inside of the ventricular tip (A), and is used to provide an axial force to insert the catheter into the ventricle until the soft silicone flange (F2 in FIG. 2) comes into contact with the dura mater. The flange (F2) is fixed to the dura mater using Histacryl or sutures (Lig. 3) so as to obtain a watertight closure of dura mater around the catheter. The side flanges (F3) at the junction of the side tube with the main catheter are fixed to the periosteum by sutures. The venous end of the tube is passed through a tunnel under the skin just posterior to the mastoid process and emerges in a neck wound made to expose the EJV or the CFV. The vein chosen for the anastomosis is tied (if the EJV is used it is tied above the valve in its lower end, if the EJV is slender the CFV can be used and it is tied at its entrance into the internal jugular vein). A side opening is made into the vein wall proximal to the tied ligature and the bulbous venous end (G) of the catheter is inserted into the vein in an upward direction for a distance of about 1 cm (FIG. 1) against the direction of the blood stream. The side opening (SL) in the vein wall is closed around the catheter using vascular sutures and a ligature (Lig. 4) is tied around the vein proximal to the bulbous venous end (G) of the catheter to prevent it slipping out of the vein. As a further measure against pulling of the catheter out of the vein during movements of the neck, a stitch (Lig. 5) is taken to anchor the catheter to the deep facia near the vein opening. The force of any pull on the catheter will be expended at the anchoring stitch (Lig. 5) and will not be effective at the catheter vein junction. Throughout the procedure clamps are applied on the side tube and on the venous segment of the catheter to prevent CSF loss. After establishing the connection, the side tube can be connected to a manometer so as to record the pressure in the cerebral ventricle or in the vein. The side tube is closed (Lig. 2) and fixed to the periosteum before closing the skin wounds.

While the invention has been specifically illustrated and described herein with reference to a preferred embodiment thereof, it is contemplated that minor modifications could be made therein without departing from the spirit of the invention.

Claims

I claim:

1. A method of treating hydrocephalus comprising the steps of establishing a connection between the lateral ventricle and a ligated neck vein using a catheter having a ventricular end and a venous end, eliminating the syphonage force which develops with conventional valve systems when the patient assumes the upright position, and preventing contact between the shunting catheter and the circulating blood by inserting the venous end of the catheter into the proximal segment of the ligated neck vein against the direction of blood flow.