Patent Application
20150112278
This application relates to surgical needles and, more particularly, to needles for insertion into the subclavian vein.
As is now in the art, approximately five million surgical procedures per year require a needle to be advanced into the subclavian vein. Once inserted, the needle can be used to place a central venous catheter. In many of these procedures, a standard, straight needle is used. However, using a straight needle can result in complications. For example, the subclavian vein is very close to the lung. If the needle is inserted too far into the body, and/or at an incorrect angle, the needle could puncture the lung.
To reduce the chance of puncturing the lung, the needle should be inserted in a medial direction and not angled toward the anterior or posterior of the patient. In other words, with the patient in the decubitus position (i.e. lying on a table), the needle should be parallel to the floor—not angled up or down. However, the humerus bone and surrounding tissue can interfere with this positioning. When the shoulder is at rest or in a forward position, the anterior of the shoulder near the humeral head can cause the needle to be angled subcutaneously toward the posterior of the patient (i.e. toward the floor), increasing the chance of puncturing the lung. Central line subclavian vein cannulation has always been fraught with complications leading to pneumothorax, hemothorax, arterial and thoracic duct punctures, venous laceration, brachial plexus and other injuries. Judicious selection of introducer needle puncture point, angle, needle advancement direction, and subcutaneous needle path are required for gaining entry into the vein. The most important requirement is for the needle to advance very close to and in parallel with the chest surface.
A scapula wedge or rolled towels can be placed underneath the patient's neck and spine to move the shoulder back and out of the way of the needle. However, the scapula wedge or roiled towel can potentially injure or make the patient uncomfortable. In addition, even with the scapula wedge in place, the shoulder can still interfere with needle placement, especially in older patients whose shoulders are not flexible.
Shaped, curved and bent needles have been used for insertion and penetration into less-accessible body locations. These needles are exclusively used for fluid introduction, aspiration, and sample retraction. In fabrication of all these needles, there is no requirement for maintaining a suitable lumen to accommodate a smoothly sliding guide wire to pass through the needle. The applications of these shaped needles include administering a fluid or local anesthetic into a ligamentary tissue of an oral cavity, spinal intrathecal space, retinal blood vessel, eye, blood vessel, human face, ear canal, and many other body locations. None of these shaped needles are usable or are intended for placement of subclavian vein catheters.
The foregoing features may be more fully understood from the following description of the drawings. The drawings aid in explaining and understanding the disclosed technology. Since it is often impractical or impossible to illustrate and describe every possible embodiment, the provided figures depict one or more exemplary embodiments. Accordingly, the figures are not intended, to limit the scope of the invention. Like numbers in the figures denote like elements.
In an embodiment, a needle for subclavian center line catheter placement includes a proximal needle portion corresponding to a straight hub and formed of a rigid material. The straight hub has an outside diameter, a hollow interior, a length, a first end configured to be coupled to a syringe, and a second end. A needle shaft portion is formed of a high hardness metal, said needle shaft portion having a first straight end rigidly affixed to a portion of the hollow interior of the straight hub.
The first straight end of the needle shaft portion includes an embedded section having a length which extends at least partially through the hollow interior of the straight huh with at least a portion of the embedded section forming a friction fit within the straight hub portion. An exposed section of the needle shaft extends distally beyond the second end of the straight hub. The exposed section of the needle shaft portion has a bent shaft portion proximate to the second end of the straight hub. A straight shaft portion distal of the bent shaft portion forms an angle sufficient to allow the straight shaft portion of the needle to be inserted into a subclavian vein without a body of a patient interfering with movement or position of the hub.
The bent shaft portion has an interior diameter substantially similar to an inner diameter of the straight shaft portion.
A method and system for the safe placement of subclavian vein catheter is described with reference to
The needle assembly 300 includes a proximal needle portion corresponding to a hub 302 formed of a rigid material and having an outside diameter, a hollow interior, and a length, and having a first end 302a configured to be coupled to a syringe and a second end 302b. The hollow interior of hub 302 is provided having a funnel shape portion 310 and a straight central longitudinal axis extending from the first end 302a to the second end 302b. Thus hub 302 is referred to as a straight hub.
Needle assembly 300 further includes a needle shaft portion formed of a high hardness metal, the needle shaft portion having a first straight end 305 rigidly affixed to a portion of the hollow interior of the straight hub 302, the first straight end of the needle shaft portion having an embedded section having a length L1 of about 0.375″ which extends at least partially through the hollow interior of the straight hub with at least a portion of the embedded section forming a friction fit within the straight hub portion and an exposed section extending distally beyond the second end of the straight hub, the exposed section having a length of about 2.5″ and an outside diameter of about 18 gauge and the exposed section of the needle shaft portion having a bent shaft portion 306 proximate the second end 302b of straight hub 302 and a straight shaft portion distal of the bent shaft portion with the bent shaft portion forming an angle of about 30 degrees from a central longitudinal axis of the straight hub 302. This particular configuration allows the straight shaft portion of the needle to be inserted into a subclavian vein without a body of a patient interfering with movement or position of the huh while the needle is inserted. For reasons which will become apparent from the description herein below, it is important that the inner diameter throughout the bent portion of the needle be substantially similar to (and ideally, identical to) the inner diameter of the straight shaft portion.
The needle 300 thus has a straight, distal portion 304 that is inserted into the patient. In an embodiment, the needle 300 has a bend 306 between the straight portion 304 and the hub 302. In one exemplary embodiment, the bent shaft portion follows a radius of about 0.8″.
The needle 300 may be partially inserted into the hub and affixed in place with an adhesive. In an embodiment, the portion of the needle 300 that extends at least partially into the hub is about 0.375 inches long.
There is an opening 308 in the proximal end of the hub where a practitioner can insert a guide wire, attach a syringe, etc., as will be discussed below. The opening can have a tapered or funneled internal section 310 that can guide a guide wire into the needle.
The interior of the needle portion (i.e. the surface of the interior walls of the needle), the interior of the hub 302 (i.e. the surface of the interior walls of the hub) form a lumen 312 having a proximal lumen aperture 308 (also referred to as a lumen opening 308) through which a guide wire can be inserted. In order for the guide wire to move smoothly through the lumen, the inner diameter of the lumen is substantially the same distal to the funnel portion 310 along the length of the needle. In particular, the inner diameter of the bent portion 306 is substantially the same as the inner diameter of the straight portion 304 so that a guide wire pushed through the needle can move smoothly through the lumen. That is, a mechanical resistance presented to the guide wire as it travels through the lumen 312 remains substantially the same as the guide wire travels through the entire length of the lumen (i.e. the mechanical resistance presented to the guide wire by the inner walls of the needle which form the lumen is substantially the same in the needle region before the bend, after the bend and in the bent region).
One skilled in the art will recognize that a conventional needle have a lumen extending there through (i.e. a conventional straight needle having a lumen) which is bent using a conventional mechanical bending technique may result in the inner needle walls (i.e. the interior surface of the inner needle walls which form the lumen) becoming partially or completely collapsed at or near the point or region of the bend (i.e. there is a collapsed lumen portion). This collapsed lumen portion makes it difficult or impossible for a guide wire to be inserted through the entire length of the lumen due to the collapsed portion partially or completely occluding the lumen.
As recognized in accordance with one aspect of the concepts sought to be protected herein, a clinician inserting the guide wire through the lumen must be able to feel resistance when the guide wire exits the distal end of the lumen and comes in contact with structures within the patient's body (e.g. a wall of a vein). As used herein, the term clinician includes but is not limited to a surgeon, physician's assistant (PA) or other medical practitioner or person performing or assisting in a medical procedure. If the clinician cannot properly feel a change in resistance of the guide wire, the clinician could inadvertently puncture the wall of the vein.
A straight needle that is bent using conventional mechanical bending techniques (and thus results in a collapsed lumen portion) will not allow a surgeon to precisely feel or detect such resistance caused by contact with a body part since the bent potion of the needle serves as a region of mechanical resistance of the guide wire.
In one exemplary embodiment, the needle is made from an 18 Gauge XTW (extra thin wall having an inside diameter in the range of 0.0410″ to 0.0430″) stainless steel hypodermic needle stock. The bent portion 306 may be bent between about 15 degrees and about 60 degrees from the centerline of the hub 302. In an embodiment, the needle may be bent at 30 degrees (substantially 30 degrees) or 45 degrees from the centerline of the huh 302.
The straight needle portion 304 may be between about two and about three inches long. In one exemplary embodiment, the straight needle portion 304 is 2.5 inches long. It has been discovered that a straight needle portion 304 of this length coupled with a bend radius (also referred to herein as a radius of curvature) of 0.8 inches to a bend angle of 30 degrees will allow the needle to be placed for insertion into the subclavian vein without substantial interference by the shoulder of the patient.
The lumen 312 may have an interior diameter between about 0.03 inches and about 0.04 inches. As noted above, lumen 312 may widen into a funnel shape inside hub 302 so that a guide wire inserted into opening 308 will be directed into lumen 312. In other embodiments, the inner diameter of the lumen 312 is larger or smaller depending upon the size of the guide wire to be introduced into the patient through the lumen. The inner diameter of lumen 312 may be slightly larger than the outer diameter of the guide wire that is used. For example, if the guide wire has a diameter of 0.032″, then the lumen may have an inner diameter of 0.034″ to accommodate the guide wire without causing friction or mechanical resistance, such that the guide wire passes substantially smoothly through the lumen 312. In an embodiment, if the inner diameter of the straight portion 304 of the needle is about 0.034″, then the inner diameter of the bent portion 306 may also be about 0.034″ so that the guide wire does not experience any substantial mechanical resistance when passing through the bent portion (ideally, the mechanical resistance presented to the guide wire by the lumen walls is the same along the entire length of the lumen).
The guide wire that passes through lumen 312 may be a flexible, coiled spring wire. Although the guide wire is flexible, if it is bent at too great an angle it may not be able to slide smoothly through lumen 312. Thus, the angle of the bend 306 should be selected sufficiently small so as to allow the guide wire to pass through the lumen with a consistent (and ideally minimal) resistance while at the same time being a sufficiently large angle so as to allow a clinician to insert the needle into a patient without interference from the patient's shoulder.
In addition, if the bend in the needle is too sharp (i.e. if the radius of curvature of the bend is too small) then the guide wire may not be able to slide smoothly through lumen 312. Thus, the bend should have a radius of curvature sufficiently large so that the bend is gentle enough for the guide wire to past through without significant resistance.
Referring to
In an embodiment, the inner diameter of bent section 408 is substantially the same as the inner diameter of straight needle section 402, so that a guide wire can pass through bent section 408 smoothly and with little resistance. In another embodiment, and as shown in
The needle hubs shown in
Referring to
In an embodiment, hub 506 includes an extension 508. The extension 508 is adjacent to the bent section 504 and extends parallel to a plane defined by the central axis of the hub 506 and the straight needle portion 502. Extension 508 may be positioned on the inside angle of bent portion 504. In other words, extension 508 is positioned on the “bottom” of hub, as shown in
The extension 508 may act as a handle that a clinician can hold during a surgical procedure. The clinician may hold the extension 508 between a finger (or fingers) and thumb to stabilize the needle assembly 500 during insertion, when inserting the guide wire, when attaching and detaching a syringe, or during other surgical events. Extension 508 may provide leverage so that the clinician can hold the needle assembly 500 still and prevent it from rotating, for example, when a syringe is attached to or removed from the huh or when a guide wire is inserted through the needle.
Referring to
Referring to
When used, with the patient in a supine position, a clinician can align the straight needle portion 701 perpendicularly to the floor and pointed medially toward the sternal notch. The hub 704 and syringe 706 can be positioned so that they are angled away from the patient's shoulder (e.g. away from the floor), so that the patient's shoulder does not interfere with placement of the needle. The needle may then be inserted into the patient's subclavian vein, just below the clavicle 710, in the direction shown by arrow 708.
Even with the patient's shoulder in a normal position, the bent needle can be positioned so that insertion is performed in a direction substantially parallel to the floor. Inserting the needle in this manner allows the needle to stay very close to the surface of the patient's chest without angling the needle subcutaneously toward the upper rib cage and lung (i.e. without angling the needle toward the floor). Because the hub 704 and syringe 706 are angled away from the shoulder, a scapula wedge, rolled towel, or other mechanism that moves the patient's shoulder out of the way is not necessary to insert the needle in a safe manner, parallel to the floor, that minimizes potential complications.
Referring now to
Referring now to
In an embodiment, the syringe 802 in
Once the guide wire is inserted into the patient's vein, the needle assembly 800 can be removed. The guide wire can then be used to insert a medicinal port (e.g. a subclavian catheter) into the vein, which can be used to administer drugs directly into the bloodstream or to perform other surgical procedures.
Manufacturing
Simply bending a surgical needle will result in the bent portion having a smaller inner diameter than the remainder of the needle. This is due to plastic deformation of the metal at the bend site. In order to manufacture a bent needle having a bent portion with an inner diameter that is substantially similar (or the same as) the inner diameter of the remainder of the needle, a force must be applied to the needle during the bending process.
Referring to
Referring to
The diameter of the wheel 1100 can be adjusted to define the radius of curvature of the bend. In an embodiment, the radius of curvature may be 0.125 inches. In other embodiments, the radius of curvature may vary from 0.125 inches to 1 inch.
As the needle is bent, the sides of the needle shaft 1000 will attempt to expand in the direction shown by arrow 1202. However, the side walls of groove 1200 will provide an equal and opposite force (shown by arrows 1204) to the needle shaft 1000 to prevent the sides of the needle from expanding and prevent the needle shaft 1000 from collapsing at the site of the bend. Because needle shaft 1000 cannot collapse during the bending process, the bent portion of the resulting bent needle will have an inner diameter that is the same as or substantially similar to the inner diameter of the remainder of the needle.
Although shown as having a rectangular shaped groove 1200, wheel 1100 can also have a rounded groove to seat the needle shaft 1000, or any other shape, so long as groove 1200 can apply force 1204 to prevent the needle shaft 1000 from collapsing during the bending process.
In an embodiment, the bent needle can have the following measurements and parameters: Angle between hub axis and needle axis—135-degrees, +/−5, degrees; Length of bent needle −2.5″, −0″ or +0.5″ Size of bent needle—18 Gauge XTW with or without an extra thin wall; Needle inside diameter—0.042″, +/−0.001″; Needle outside diameter—0.050″, +/−0.0005″; Needle material—stainless steel, hypodermic needle stock.
Having described preferred embodiments, which serve to illustrate various concepts, structures and techniques, which are the subject of this patent, it will now become apparent to those of ordinary skill in the art that other embodiments incorporating these concepts, structures and techniques may be used. Accordingly, it is submitted that that scope of the patent should not be limited to the described embodiments but rather should be limited only by the spirit and scope of the following claims. All references cited herein are hereby incorporated herein by reference in their entirety.
