Patent Application
20240050638
This invention relates generally to surgical suction tubes, and, more particularly, to a disposable suction tube with an integrally formed injection molded handle having finger pads separated by a gap that mitigates deformations due to thermal gradients during molding.
A Fukushima suction tube is a suction device that surgeons (e.g., neurosurgeons) use to remove fluids and other materials from an operative site, in order to achieve an enhanced view of critical structures. The device includes a handle having a teardrop-shaped control slot in a finger pad that allows for precise regulation of suction. A channel extends through the handle. A suction hose attaches to one end of the handle. A cylindrical tubular tip is attached to the other end of the handle. The tip has an internal diameter measured on the French scale, typically ranging from 3F to 12F. The tip is malleable, allowing a practitioner (e.g., neurosurgeon) to bend the tip to provide good access to a surgical site.
Fukushima suction tubes are typically reusable devices. They are typically comprised of stainless steel. They must be cleaned and sterilized between procedures, after each use. Autoclave sterilization alone is insufficient, because, during use, contaminants enter and adhere to the interior of the tip. Manufacturers provide a thin flexible wire stylet to insert into the device and move back and forth for the purpose of mechanically removing any contained contaminants. This method of cleaning is not only tedious, but fraught with risk of missing contained contaminants.
During an operation, a surgeon uses an implement, such as a knife, to cut and penetrate or remove tissue, while a cautery device is used to cauterizes tissue, and the suction tube removes fluids and debris. The devices compete for access to the operative, with the surgeon's implement being of paramount importance. The malleable tubular tip of the suction devices is typically straight or slightly angled, neither of which allows access to the operative site without raising the handle to a position that blocks access by the knife or cautery. To gain access without substantially interfering with the surgeon's instrument, and avoid what medical professionals refer to as a sword fight, a practitioner will bend the malleable tip of the suction device. The bending is imprecise and may kink or partially occlude the tip. Sometimes the bending must be undone and redone several times to achieve the goal. As the inner diameter of the tip is small, any occlusion impedes flow and contributes to capture of contaminants. Such occlusion also compromises reusability. With the imprecisely bent tip, the practitioner may extend the tip into the operative sight, without positioning the handle in the way of the knife or cautery instrument.
Another shortcoming of conventional Fukushima suction tubes is limited ergonomics. The finger pads accommodate one finger (e.g., an index finger) on the bottom of the finger pad and a thumb on top of the finger pad. While other grips are possible, the device lacks defined finger placement structure, for stable gripping along the sides of the finger pad. The current devices are not well suited to gripping on each side between a thumb and middle finger while the index finger manages the teardrop-shaped control slot. Such a grip is particularly desirable for control and accurate positioning.
Lee (US 20080177251 A1) describes a conventional Fukushima suction tube with a straight tube, upper and lower plates extended from the middle section of the straight tube, a teardrop air control portion disposed at the middle of the upper plate and penetrating inside the straight tube. Space between Lee's upper and lower plates is occupied by a series of vertical ribs that extend between Lee's upper and lower plates. The ribs cause serious molding problems that preclude plastic injection molding.
When plastic is injected into a mold, the injected plastic contacts the mold. The mold is cooler than the plastic. At the point of contact, the plastic begins to cool via conduction. In areas where there are wider spaces, the greater mass of plastic stays molten longer. Thus, injected plastic cools at different rates based on mass/thickness. If a wall thickness suddenly changes, such as where a rib extends from a surface of Lee's plates, the thicker cross-section where the wall and rib meet will continue to cool and shrink long after the portions of the wall devoid of such ribs. This cooling differential causes a sink and warpage to form on the wall at the thicker area. Voids form when the solid skin is strong enough to withstand the negative pressure that builds as the polymer melt cools and shrinks without compensation. A sink is a dip (depression) in the surface of a plastic part that generally coincides with an internal structure. Warping occurs and sinks form because cooling is inversely related to mass. Each such defect (i.e., voids, sinks and warpage) would deform the shape of the plates and the shape of the teardrop slot, rendering the device unacceptable to users, e.g., neurosurgeons.
Additionally, conventional Fukushima suction tubes include finger placement surfaces that are generally planar, as in Lee (US 20080177251 A1). Conventional reusable devices are stainless steel structures. Fingers easily slide off the finger pads of such devices. On such surfaces, quickly finding the center of a pad, maintaining a finger centered and precisely controlling a teardrop slot can be extremely difficult.
A disposable injection molded Fukushima suction tube is needed. The tube should avoid deformations due to thermal gradients during injection molding. The tube should also facilitate accurate finger placement during use. The tube should also facilitate tip angling, without tip bending or occlusion, to facilitate flow during use.
The invention is directed to overcoming one or more of the problems and solving one or more of the needs as set forth above.
To solve one or more of the problems set forth above, in an exemplary implementation of the invention, a disposable suction tube instrument includes a metal tubular tip with a curvature that facilitates operative site access, intimate surface contact while allowing space for aspiration of solids, liquids and gasses, without impeding access by other instruments. An integrally formed injection molded plastic handle includes upper and lower finger pads separated by a gap that provides finger recesses for gripping and also provides shrinkage relief to avoid distortion of a teardrop control slot during post-molding cooling.
An exemplary surgical suction tube device according to principles of the invention includes an integrally formed injection molded plastic handle and a tip. The handle includes a body with a longitudinal axis, a body width, an inlet end, an outlet end, an upper side, a lower side, the outlet end is opposite the inlet end, the upper side is opposite the lower side, a hose fitting at the outlet end, an inlet at the inlet end, and a central channel extending through the body from the outlet end to the inlet. The handle also includes a pair of finger pads, including an upper finger pad and a lower finger pad. The upper finger pad is disposed on the upper side of the body between the hose fitting and inlet. The lower finger pad is disposed on the lower side of the body between the hose fitting and the inlet and in alignment with the upper finger pad. Each finger pad includes a contact surface having a central axis, a pad width and a pad length. The central axis of each finger pad is parallel to the longitudinal axis of the body. The pad width is greater than the body width. The central axis of each finger pad and the longitudinal axis of the body is aligned. Side gaps are provided between the upper finger pad and lower finger pad, including a first side gap and a second side gap opposite the first side gap. A suction control slot extends through the upper finger pad to the central channel of the body of the handle. The tip is a metal tube with a free end and a proximal end opposite the free end. The proximal end of the tip is attached to the inlet of the body.
The first side gap includes a first height. The second side gap includes a second height. The upper finger pad has an upper finger pad thickness. The lower finger pad has a lower finger pad thickness. The first height is greater than each of the upper finger pad thickness and the lower finger pad thickness. The second height is about equal to the first height. The first height is effective to prevent shrinkage of the suction control slot during post-injection molding cooling and to provide a fingertip recess between the upper finger pad and the lower finger pad. The first height may be about equal to the sum of the upper finger pad thickness and the lower finger pad thickness. The first height may be about equal to 0.140 in. The first height may be at least as great as the sum of the upper finger pad thickness and the lower finger pad thickness. The pad length (i.e., length of each finger pad) may be greater than the pad width. The pad length is greater than the length of the suction control slot. The pad width is greater than a maximum width of the suction control slot 0.140
The metal tube comprising the tip is a stainless-steel tube with an inner diameter from 3F to 12F. The free end of the tip is blunted, deburred and buffed. The metal tube may be curved and have a radius of curvature of 4 to 12 inches and extend for an arc angle of 40 to 60 degrees; and/or have a radius of curvature of 4 to 12 inches, and a chord measured from the free end to the proximal end having a length of 3.5 to 7.0 inches; and/or have an arc angle of 40 to 60 degrees, and a chord measured from the free end to the proximal end having a length of 3.5 to 7.0 inches.
In an embodiment, a surgical suction tube device includes a tip and an integrally formed injection molded plastic handle. The handle is an injection molded plastic structure. The handle includes a body with a longitudinal axis, a body width, an inlet end, an outlet end, an upper side, and a lower side. The outlet end is opposite the inlet end. The upper side is opposite the lower side. A hose fitting is provided at the outlet end. An inlet is provided at the inlet end. A central channel extends through the body from the outlet end to the inlet. A pair of finger pads, including an upper finger pad and a lower finger pad, is provided. The upper finger pad is disposed on the upper side of the body between the hose fitting and inlet. The lower finger pad is disposed on the lower side of the body between the hose fitting and the inlet and in alignment with the upper finger pad. Each finger pad includes a concave contact surface having a central axis, a pad width and a pad length. The central axis of each finger pad is parallel to the longitudinal axis of the body. The pad width is greater than the body width. The first portion of each finger pad extends beyond a first side of the body. A second portion of each finger pad extends beyond a second side of the body. Side gaps are provided between the upper finger pad and lower finger pad. The gaps include a first side gap and a second side gap opposite the first side gap. The first side gap is coextensive with the first portion of each finger pad extending beyond a first side of the body. The second side gap is coextensive with the second portion of each finger pad extending beyond a second side of the body. The first side gap is devoid of any structure extending between the upper finger pad and lower finger pad. The second side gap is devoid of any structure extending between the upper finger pad and lower finger pad. The side gaps provide shrinkage relief during molding.
A suction control slot extends through the upper finger pad to the central channel of the body of the handle. The tip includes a metal tube with a free end and a proximal end opposite the free end. The proximal end of the tip is attached to the inlet of the body.
In one embodiment, the first side gap has a first height and the second side gap has a second height. The upper finger pad has an upper finger pad thickness. The lower finger pad has a lower finger pad thickness. The first height is greater than each of the upper finger pad thickness and the lower finger pad thickness, to provide shrinkage relief during molding. The first height is effective to prevent shrinkage of the suction control slot during post-injection molding cooling. The first height is also effective to provide a fingertip recess between the upper finger pad and the lower finger pad. The first height is equal to the sum of the upper finger pad thickness and the lower finger pad thickness. In one embodiment, the first height is about 0.140 in. The first height is at least as great as the sum of the upper finger pad thickness and the lower finger pad thickness. The pad length is greater than the pad width. The pad length is greater than the length of the suction control slot. The pad width is greater than a maximum width of the suction control slot. The central axis of each finger pad and the longitudinal axis of the body is aligned.
The metal tube may be a stainless-steel tube with an inner diameter from 3F to 12F. The metal tube may have a free end that is blunted, deburred and buffed. The metal tube may be curved and have a radius of curvature of 4 to 12 inches and extend for an arc angle of 40 to 60 degrees and/or define a chord measured from the free end to the proximal end having a length of 3.5 to 7.0 inches.
The foregoing and other aspects, objects, features and advantages of the invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where:
Those skilled in the art will appreciate that the figures are not intended to be drawn to any particular scale; nor are the figures intended to illustrate every embodiment of the invention. The invention is not limited to the exemplary embodiments depicted in the figures or the specific components, configurations, shapes, relative sizes, ornamental aspects or proportions as shown in the figures.
An exemplary suction tube device according to principles of the invention includes a tubular tip with a curvature that facilitates operative site access, intimate surface contact while allowing space for aspiration of solids, liquids and gasses, without impeding access by other instruments. The device is disposable, which avoids risks of contamination. The handle is an integrally formed (integrally-formed) structure, which is comprised of injection molded plastic. The handle includes upper and lower finger pads separated by a functionally-significant gap. The gap provides finger recesses, such as for gripping on each side between a thumb and middle finger while the index finger manages a teardrop-shaped control slot. Such a grip is particularly desirable for control and accurate positioning. The gap also provides shrinkage relief. Without the gap, after molding, the teardrop-shaped control slot would shrink, thereby limiting and distorting flow control. In sum, the device is easy to grip including along its sides, disposable, easy to position at an operative site without impeding visibility or access by other instruments, and provides an industry-accepted teardrop-shaped control slot.
Referring to
A body 135 extends from the collar 130 to the tip joint 170. The body 135 is a tubular structure. As discussed below, a central channel extends through the body. Aspirated matter flows through the central channel of the body 135.
A finger grip 140 includes an upper finger pad 145 and a lower finger pad 146. Each finger pad 145, 146 is a broad thin panel that provides a surface to receive at least one fingertip. In the nonlimiting example of
In the exemplary embodiment shown in
As evident in the side view of
Additionally, the edges of the finger pads 145, 146 are filleted (i.e., rounded) to avoid any sharp corners that may irritate fingers. The concavity is functionally significant, as it greatly facilitates proper finger positioning. Finger positioning is critical to efficient and optimal use of the device during surgery.
A slot-like gap 147, 148 is provided between the finger pads 145, 146, along each side of the handle 105. Each gap 147, 148 is devoid of structure between the finger pads 145, 146. The handle 105 is symmetrical. The gap 147, 148 extends, on each side of the handle 105, between the outwardly extending portion of each finger pad 145, 146, to the body 135 of the handle 105.
The configuration and arrangement of the gaps 147, 148, and finger pads 145, 146, including their relative dimensions and proportions are important to facilitate shrinkage relief during molding. The height of the gap 147, 148 is greater than the thickness of each finger pad 145, 146. In the nonlimiting example of
The gap 147, 148 is functionally significant. It provides a recess for fingers. With the gaps 147, 148, a user may grip the handle 105 with a thumb in the gap on one side of the finger pads 145, 146 and a middle finger in the gap on the other side of the finger pads 145, 146, while the index finger manages the teardrop-shaped control slot 150. Such a grip is particularly desirable for control and accurate positioning. It is an alternative to the conventional grip, in which a thumb engages one finger pad surface, while the index or middle finger engages the other finger pad surface.
The gap 147, 148, being devoid of structure between the finger pads 145, 146, provides shrinkage relief If the gap 147, 148 was omitted and the sides between the finger pads 145, 146 were solid, as in a conventional Fukushima suction tube, or if the gap 147, 148 contained structures extending between finger pads 145, 146, the finger pads 145, 146 would warp and the teardrop-shaped control slot 150 would deform during cooling, after injection molding. Shrinkage of the injection molded handle 105 during post-molding cooling would appreciably distort the shape and dimensions of the pads 145, 146 and teardrop-shaped control slot 150 in the upper finger pad 145. Such distortion would compromise the utility, and practitioner acceptance, of the handle 105. The gaps 147, 148 allow post-molding cooling of the thin separated finger pads 145, 146 without appreciable distortion of the teardrop-shaped control slot 150.
When plastic is injected into a mold, the injected plastic contacts the mold. The mold is cooler than the plastic. At the point of contact, the plastic begins to cool via conduction. In areas where there are wider spaces, the greater mass of plastic stays molten longer. Thus, injected plastic cools at different rates based on mass/thickness.
If a wall thickness suddenly changes, such as where a rib extends from the back side of a wall, the thicker cross-section where the wall and rib meet will continue to cool and shrink long after the portions of the wall devoid of such ribs. This cooling differential causes a sink and warpage to form on the wall at the thicker area. Depending on the mass differential, the sink could be fairly minor or it could produce a void. Voids form when the solid skin is strong enough to withstand the negative pressure that builds as the polymer melt cools and shrinks without compensation. The sink is a dip (depression) in the surface of a plastic part that generally coincides with an internal structure. Warping occurs and sinks form because cooling is inversely related to mass. Thus, thicker plastic cools slower than thinner plastic. Thicker plastic retains heat longer than thinner plastic. See, Plastic Part Design for Injection Molding: An Introduction, 2nd Edition, by Robert A. Malloy, Hanser Publishers (2010), ISBN: 978-1-56990-436-7, 1-56990-436-7, p. 67; Complete Part Design Handbook For Injection Molding of Thermoplastics, by E. Alfredo Campo, Hanser Publishers (2006), ISBN: 978-3-446-40309-3,3-446-40309-4, pp. 211-214. The schematic provided as
Voids 405, sinks 410, and warpage 415 are defects that compromise utility of the device. First, voids 405, sinks 410, and warpage 415 compromise structural integrity of the upper and lower plates. Concomitantly, the defects would change the shape (i.e., contour) of the upper and lower pads 145, 146, by adding undulating warpage and sinks. Such defects would interfere with a finger maintaining a seal over portions of the air control slot 150. Neurosurgeons, who are, by necessity, very precise, would shun any flow controller that includes deformed upper or lower plates.
Additionally, such defects would deform the shape of the teardrop-shaped slot 150. The shape and size of the slot 150 is consistent among such surgical suction devices. A neurosurgeon could not tolerate any variation from the standard shape and size, as it would interfere with proper suction. Neurosurgeons expect a certain shape and size. Through experience, they know exactly how much to move their finger to increase, decrease, disrupt or maximize suction. A distorted slot would prevent such use, with potentially serious consequences.
During molding, the gaps 147, 148, are undercuts. Mold lifters (or sliders) eject the handle upon injection molding. The lifters move in two dimensions to release and facilitate ejection. The invention is not limited to any particular lifters or sliders for part release and ejection.
The suction control slot 150 extends through the upper finger pad 145 to the central channel of the handle 105. The exemplary handle 105 depicted in
A tip joint 170 includes an inlet 175 into which a tip 200 is mounted. The tip 200 is coupled to the tip joint 170 via bonding, such as with a glue. The glue is suitable for joining the stainless-steel tip 200 to the plastic of the handle 105.
Referring to the section views of
A radius of curvature may be computed using the chord length and arc angle in
The radius of curvature for each example is provided in the table below. For chord lengths of about 4 to 6.5 inches (+/−0.25 inches), these radii, radii in between these radii, and radii within an inch of the minimum and maximum radii in the table, are effective for providing a curvature of the tip that facilitates access in accordance with the principles of the invention.
Any dimensions, amounts or concentrations are provided as approximations for a particular embodiment, unless expressly stated otherwise. The dimensioned views of a handle of an exemplary suction tube device according to principles of the invention, as provided in
While an exemplary embodiment of the invention has been described, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum relationships for the components and steps of the invention, including variations in order, form, content, function and manner of operation, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. The above description and drawings are illustrative of modifications that can be made without departing from the present invention, the scope of which is to be limited only by the following claims. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents are intended to fall within the scope of the invention as claimed.
This invention is a continuation in part and claims the benefit of priority of U.S. Nonprovisional patent application Ser. No. 17/819,392, filed Aug. 12, 2022, the entire contents of which are incorporated herein and made a part hereof by this reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17819392 | Aug 2022 | US |
| Child | 18346835 | US |
