Patent Description:
There are a number of treatments for medical conditions which require fluid to be removed from an organ or tissue of a patient. One such condition is hydrocephalus, where cerebrospinal fluid abnormally accumulates in the skull faster than it is withdrawn by the body. The excessive build-up of cerebrospinal fluid compresses brain tissues, which eventually leads to brain damage.

Hydrocephalus is commonly treated by implanting a shunt in fluid communication with a ventricle within the brain to withdraw cerebrospinal fluid at a desired rate. Typically, the rate of withdrawal of cerebrospinal fluid, also referred to herein as "CSF", is controlled by a valve having different pressure settings which a clinician adjusts pre-operatively. A number of shunt valves can be noninvasively changed after implantation, such as the Codman® Hakim® programmable valve which is currently commercially available from Codman & Shurtleff, Inc. of Raynham, Massachusetts. Also available from Codman & Shurtleff, Inc. is the CERTAS™ programmable valve that is disclosed and claimed in <CIT>.

External CSF drainage systems are typically utilized in a clinical setting when it is desirable to drain CSF through a catheter into an external "closed" collection system to prevent infection of the CSF during management of intra-cranial pressure. Removal of too much CSF, or "over-drainage", through the catheter is undesirable and may result in severe headaches or collapse of one or more ventricular cavities within the brain. To reduce the risk of over-drainage, physicians typically drain CSF at a rate of <NUM> to <NUM> per hour.

Withdrawal of excessive CSF can also result in "over-filling" of the external drainage system. Various problems may result from over-filling, including leakage of fluid from the system and resulting infection through the pathway provided by the leaking fluid.

Many conventional drainage systems crudely control flow rate of CSF by adjusting the level at the which the system is positioned above the head or spine of the patient. In other words, gravity and fluid pressure generated within the patient and within the system affect flow rate into a collection chamber. Flow may unexpectedly increase if the level of the system is lowered in relation to the level of the catheter entering the patient, such as when a patient sits up after lying in a prone position.

One system disclosed by Eckermann in <CIT> attempts to measure the volume of fluid in a collection chamber utilizing one or more sensors. In other words, proper functioning of this system appears to require correct operation of the sensors.

Another system disclosed by <CIT> utilizes a buoyant float to seal an inflow port or a vent port of a chamber. However, this system is not optimal because the volume of the chamber appears to be fixed. Thus, the float does not appear to be adjustable to accommodate different volumes of CSF fluid if a physician selects an alternate volume of CSF to be drained.

It is therefore desirable to have a simple yet reliable and adjustable system and technique to drain bodily fluids such as cerebrospinal fluid.

<CIT> discloses a non-invasively adjustable intercranial pressure regulator valve and adjustment mechanism therefor which is adapted particularly for the treatment of hydrocephalus and the draining of cerebrospinal fluid (CSF) from a ventricle in the brain to another location in the patient's body. The valve includes a flexible diaphragm which is contacted on both sides by the CSF fluid. A valve seat on the diaphragm is movable with the diaphragm and a ball closure valve is positioned on the cephalad side of the diaphragm. The pressure differential of the CSF fluid across the diaphragm causes the valve seat to flex into and out of engagement with the ball closure valve. The force by which the ball closure valve and valve seat engage each other and, thereby, the pressure differential at which the CSF fluid will drain are adjusted by an adjustment means.

<CIT> discloses a urinary catheter having a pair of longitudinally-spaced passage closing means which may be individually and sequentially operated for draining the urinary bladder and when in closed position providing an air lock effectively preventing transmission of infecting agents into the bladder.

<CIT> discloses a method of treating tissue damage which comprises applying a negative pressure to a wound sufficient in time and magnitude to promote tissue migration and thus facilitate closure of the wound. The method is applicable to wounds, burns, infected wounds, and live tissue attachments. A wound treatment apparatus (<NUM>) is provided in which a fluid impermeable wound cover (<NUM>) is sealed over a wound site. A screen (<NUM>) in the form of an open cell foam screen or a rigid porous screen is placed beneath the wound cover (<NUM>) over the wound. A vacuum pump supplies suction within the wound cover (<NUM>) over the treatment site.

<CIT> discloses a drain valve which consists of a tubular cylindrical body which is open at both ends. It has an inlet at one end with a seat for a shut-off valve. Several weights compensate for differences in the height of the fluid column as a function of the position of the patient. The weights are in the form of three balls, the first of which presses against the shut-off valve, which is also in the form of a ball. The third ball is held in place by a spring which is fixed by a threaded ring, which has its aperture forming the valve outlet. During use a catheter attached to the inlet end of the valve is located in the cerebral ventricle of the brain to be drained. The other has a drain catheter with its end located in the peritoneal cavity.

<CIT> discloses a fluid collection system which includes a disposable collection container and a disposable collection container receiving housing, the housing having a cavity and a suction source. The fluid collection container may include a flexible liner and a shelf for diverting fluid from the suction and to assist with a collapse of the liner during evacuation of the fluid from the liner. The collection container receiving housing may include a piston assembly having a main piston body and a scraper ring. The collection container receiving housing may include a piston stop feature. The system may include a partially hydrophobic filter and a flat surface suction tool.

An object of the present invention is to provide a system and technique to selectively drain a desired quantity of bodily fluid such as cerebrospinal fluid from a patient. Such a system is described in claim <NUM>.

Another object of the present invention is to provide such a system and technique which easily yet reliably enables adjustment of the volume of bodily fluid actually drained from the patient. This invention features a system suitable for draining at least one type of bodily fluid, such as cerebrospinal fluid, from a patient. The system includes a chamber capable of being adjusted to hold one of at least a first volume of fluid and a second, smaller volume of fluid. The chamber has an inlet end with a barrier defining an opening and has an outlet end defining an outlet passage. The system further includes a valve with a valve seat and a valve closure member to define a usable volume within the chamber, and a movable adjustment member with a shaft passable through the opening in the barrier and terminating within the chamber at a first end. The first end of the shaft is connected to the valve seat, and the shaft has a plurality of features along at least a portion of its length engagable with corresponding engagement features in a fixed relationship with the barrier to enable the shaft to be advanced into the chamber to reduce the usable volume to be less than the first volume.

In certain embodiments, the valve closure member includes a feature which is buoyant relative to the fluid to be drained, and the valve includes a cage structure to control movement of the buoyant feature between at least first and second positions representing the first volume and the second volume, respectively. In some embodiments, the shaft is rotatable and defines a helical thread along at least a portion of its length. The adjustment member includes a grip member attached to the shaft, the grip member being graspable by a user of the system to impart rotation to the shaft.

In a number of embodiments, the system further includes tubing defining a lumen in fluid communication with the valve seat. Preferably, the shaft defines a longitudinal channel and a portion of the tubing passes through the channel. In some embodiments, a sleeve surrounds at least a portion of the shaft to assist in isolating the shaft from fluid within the chamber, and the barrier includes a filter to restrict entry of microbes past the barrier and into the chamber.

In what follows, preferred embodiments of the invention are explained in more detail with reference to the drawings, in which:.

This invention may be accomplished by a system for draining at least one type of bodily fluid, such as cerebrospinal fluid, from a patient. The fluid may include fragments of bone, soft tissue, or other debris. The system includes an assembly having a chamber capable of being adjusted to hold one of at least a first volume of fluid and a second, smaller volume of fluid. The chamber has an inlet end with a barrier defining an opening and has an outlet end defining an outlet passage. The system further includes a valve with a valve seat and a valve closure member to define a usable volume within the chamber, and a movable adjustment member with a shaft passable through the opening in the barrier and terminating within the chamber at a first end. The first end of the shaft is connected to the valve seat, and the shaft has a plurality of features along at least a portion of its length engagable with corresponding engagement features in a fixed relationship with the barrier to enable the shaft to be advanced into the chamber to reduce the usable volume to be less than the first volume.

System <NUM> according to the present invention, <FIG>, includes an assembly <NUM> having a housing <NUM> that defines a volume-limiting containment chamber <NUM> capable of being adjusted to hold one of at least a first volume of fluid and a second, smaller volume of fluid. The chamber <NUM> has an inlet end <NUM> with a barrier <NUM>, such a cap with rib <NUM> and a cover <NUM> defining an opening <NUM>, the barrier <NUM> being fixed to housing <NUM> in one construction and, in another construction, being removably attached. Chamber <NUM> also has an outlet end <NUM> defining an outlet passage <NUM>.

As illustrated in enlarged detail in <FIG>, system <NUM> further includes a valve <NUM> with a valve seat <NUM> and a valve closure member <NUM>, such as a buoyant spherical float, to define a usable volume within the chamber <NUM>. Valve <NUM> preferably includes an elongated containment cage <NUM> to control alignment of closure member <NUM> relative to valve seat <NUM> over a range of desired containment volumes.

Assembly <NUM> further includes a movable adjustment member <NUM> with a shaft <NUM> passing through the opening <NUM> in the barrier <NUM> and terminating within the chamber <NUM> at a first, interior end <NUM>. The first end <NUM> of the shaft <NUM> is connected to the valve seat <NUM>, and the shaft has a plurality of features, such as helical thread <NUM> along at least a portion of its length engagable with corresponding engagement features, such as mating or matching lands and grooves of a similar helical thread, in a fixed relationship with the barrier <NUM> to enable the shaft <NUM> to be advanced into the chamber to reduce the usable volume to be less than the first volume, as described in more detail below.

System <NUM> includes drain line tubing <NUM> having a distal end (not shown) coupled to a medical device, such as a shunt or other type of catheter, in fluid communication with the bodily fluid to be drained. A proximal end <NUM>, <FIG>, of the tubing <NUM> passes through a central passage <NUM> in shaft <NUM> and is in fluid communication with the chamber <NUM>. In one construction, proximal end <NUM> of tubing <NUM> is attached directly to valve seat <NUM> as indicated by dashed line <NUM>; in another construction, a portion of tubing <NUM> is "potted" within passage <NUM> of shaft <NUM> by an epoxy <NUM> or other polymeric material. The technique of attaching tubing <NUM> to assembly <NUM> is a matter of design choice, with engineering factors including the amount of rotation of shaft <NUM> as described in more detail below.

As illustrated in <FIG>, this construction of system <NUM> further includes a secondary drain valve <NUM> connected to outlet passage <NUM> by tubing <NUM>. Valve <NUM> includes a movable control lever <NUM> which alters fluid flow into secondary bag <NUM> to a sampling port <NUM>. Also shown in <FIG> are lines <NUM> and <NUM> in tubing <NUM> representing the boundaries of a quantity <NUM> of cerebrospinal fluid being drained into assembly <NUM>. A grip <NUM>, such as a knob, is attached to exterior end region <NUM> of shaft <NUM> to enable a user to impart rotation to shaft <NUM> as described in more detail below.

Additional features in this construction are shown in <FIG>. Barrier <NUM> may include vent channels <NUM> and <NUM>, shown in phantom, defined by cover <NUM>. Preferably, a disk-like filter <NUM> cooperates with an elastic, cylindrical sleeve <NUM> to isolate chamber <NUM> from microbes and other contaminants in the external environment while enabling venting of gases displaced by fluid entering chamber <NUM>. Barrier <NUM> further includes cylindrical side wall <NUM> and floor <NUM> defining vent openings <NUM> and <NUM>. Rib <NUM> includes at least one exterior passage <NUM> through which a retaining element or a securing element may be placed.

External markings <NUM>, <NUM>, <NUM> and <NUM> can denote volumes such as <NUM>, <NUM>, <NUM> and <NUM>. Dashed lines <NUM> and <NUM> represent minimum and maximum volumes, respectively, which are achieved by moving valve seat <NUM> via shaft <NUM>. Preferably, assembly <NUM> is constructed of polymeric materials. In some constructions, at least housing <NUM> is formed of a translucent material, preferably substantially transparent, to enable visualization of collected fluid within chamber <NUM>.

In the preferred construction illustrated in <FIG>, valve seat <NUM> is connected to shaft <NUM> by fingers or inner projections <NUM>, <NUM> which slidably engage a channel <NUM> defined in end <NUM> of shaft <NUM>. In one construction, fingers <NUM>, <NUM> extend inwardly from wall <NUM> of valve seat <NUM>. This connection decouples or isolates seat <NUM> from the rotation of shaft <NUM>. Valve seat <NUM> includes chamfer <NUM>, hemispherical sealing region <NUM> which mates with ball float <NUM>, and inner opening <NUM> which enables tubing <NUM> to communicate with chamber <NUM>. In some other constructions, valve seat <NUM> is formed on, and is a part of, the inner end <NUM> of shaft <NUM> and/or the proximal end <NUM> of tubing <NUM>.

Cage <NUM> includes elongated guide elements <NUM>, <NUM>, <NUM> and an additional guide element that is not shown. The plurality of guide elements of cage <NUM> ensure that ball float <NUM> will positively engage seat <NUM> in whatever axial position seat <NUM> is placed by movement of shaft <NUM>.

Arrows <NUM> and <NUM> represent the flow of cerebrospinal fluid or other bodily fluid through tubing <NUM> into chamber <NUM>, as limited by valve <NUM>. Arrow <NUM> represents the axial movement of shaft <NUM> as it is advanced via rotation imparted by a user to reduce the usable volume within chamber <NUM> from the maximum volume <NUM> down to a selected volume as small as minimum volume <NUM>.

Claim 1:
A system (<NUM>) suitable for draining at least one type of bodily fluid from a patient, comprising:
a chamber (<NUM>) capable of being adjusted to hold one of at least a first volume of fluid and a second, smaller volume of fluid, the chamber having an inlet end (<NUM>) with a barrier (<NUM>) defining an opening (<NUM>) and having an outlet end (<NUM>) defining an outlet passage (<NUM>);
a valve (<NUM>) including a valve seat (<NUM>) and a valve closure member (<NUM>) to define a usable volume; and
a movable adjustment member (<NUM>) having a shaft (<NUM>) passable through the opening (<NUM>) in the barrier (<NUM>) and terminating within the chamber (<NUM>) at a first end, the first end (<NUM>) being connected to the valve seat (<NUM>), the shaft (<NUM>) having a plurality of features along at least a portion of its length engagable with corresponding engagement features being in a fixed relationship with the barrier (<NUM>) to enable the shaft to be advanced into the chamber to reduce the usable volume to be less than the first volume.