Background and Summary of the Invention

One of the most common injuries sustained by humans and animals is the accidental penetration of the skin by foreign objects, such as pieces of metal, glass, wood, needles, pencil lead, bullets, BB pellets, nails, screws, fiberglass, paints and pigments. When part of the foreign body still protrudes outside the skin it can be removed fairly easily. However, when the foreign body has penetrated the skin with substantial projectile velocity so that it is completely embedded beneath the skin in deeper tissues, removal is often difficult. This is due to the fact that there may be variation in the direction and depth to which the foreign body has traveled. The presence of the entry wound is of help. When the entry wound is completely healed, locating the object becomes more difficult.

Utilizing currently available materials and techniques, a surgeon can encounter a great deal of difficulty in finding small embedded objects, often spending as much as one half to one and a half hours, or even longer, in the attempt to locate and remove the foreign body. This is true, even though pre-operative X-rays are taken in an effort to localize the position of the object.

Because of the difficulties described above, many surgeons, veterinarians, and podiatrists require fluoroscopic studies to be done in the operating room during the removal procedures. These often are long, drawn-out procedures, which undesirably subject the patients to prolonged anesthesia and excessive X-ray exposure.

Using the device and method of the invention, a pre- operative X-ray study is made of the traumatized area, to precisely pinpoint the location of the foreign body and allow the surgeon

thereafter to quickly effect its removal, often reducing to a fe minutes procedures heretofore requiring extensive time, patienc and effort.

The invention is a novel grid-like screen, formed of material opaque to X-rays, preferably thin stainless steel but als tin-lead or lead-plated copper, and the method of use of th screen. When a patient presents a history to a doctor suggestin the possible presence of an embedded foreign body, an X-ray i taken to verify its presence or absence. If its presence i confirmed, then the invention comes into play. The screen i carefully placed over the anatomic part with a targeting elemen directed over the point of injury or entry wound or a marked point, these constituting a targeting mark. It is held in this positio or taped in place. The anatomic part is then turned or manipulate so that the screen rests against the cassette holding the film. A X-ray image is taken, which will incorporate the grid pattern an fix the location of the foreign object with respect thereto in two-dimensional plane. The screen is then re-positioned at righ angles to its first orientation with the targeting element agai aligned with the previously selected injury or marked point, and second X-ray image is taken with the screen again positione against the film cassette. These two X-ray images are used by th surgeon to triangulate the location of the foreign body, an determine and mark where the incision should be made in order to retrieve it. The surgeon can then quickly effect its removal. If, under certain circumstances, it is not possible to manipulate the anatomic part so that the screen rests directly against the film cassette, then the screen can rest between the X-ray source and the anatomic part. This is not the preferred method. For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of a preferred embodiment and to the accompanying drawings.

Description of the Drawings

Fig. 1 is a plan view of a grid-like screen embodying m invention;

Fig. 2 is an enlarged side elevational cross-sectional view taken along lines 2-2 of FIG. 1;

Fig. 3 is a plan view of a patient's hand with an embedded foreign body, illustrating the use of the positioning of the screen over the palm of the hand;

Fig. 4 is a side elevational, schematic view showing the relational placement of the X-ray source, the anatomical part, the screen, and the X-ray film cassette while the X-ray is being taken;

Fig. 5 is a plan view of an X-ray film copy resulting from the exposure in an antero-posterior position and showing the foreign body and the targeting element in a two-dimensional relationship;

Fig. 6 is a plan view showing the patient's finger reoriented at right angles with respect to its position in Fig. 3 thus constituting a medio-lateral view;

Fig. 7 is a plan view of an X-ray film resulting from the exposure in the medio-lateral position of Fig. 6 and showing the foreign body and the targeting element in a two-dimensional relationship, at right angles to that shown in Fig. 5;

Fig. 8 is a schematic cross-sectional view of the finger of Fig. 6, taken at the level of the point of entry, to show the tangential alignment of the targeting mark with the screen targeting element positioned for the second X-ray image; and

Fig. 9 is a greatly enlarged fragmentary cross-sectional view as taken generally along line 9-9 of Fig. 3. Description of a Preferred Embodiment Referring now to the drawings, and more particularly to

Figs. 1-3, the reference numeral 10 designates a patient's hand, the index finger 11 of which contains an embedded foreign body 12. In the illustration, the foreign object is in the form of a rod-

like element which has entered the finger 11 near the second joint leaving an observable entry wound 13, and has travelled considerable distance along a path 21 (Figs. 3 and 5) before comin to rest. To assist the surgeon is locating the position of th object, the invention provides a novel grid-like screen 14, (Figs 1 and 2) formed of a material opaque to X-rays, which can be place over the injury site, in this case the patient's hand 10. Th opacity of the material to X-radiation must be sufficient that th grid pattern is clearly visible in an X-ray image of the hand take through the grid. Stainless steel sheet, formed into a grid-lik screen, is an ideal material for this purpose. Variations includ tin-lead or lead-plated copper. The optimum dimensions, thickness, and grid size are a function of the area to be imaged. For th hand, suitable screen dimensions are about 3 1/4" by 6 1/4", wit a minimal thickness of about 2 mils, and preferably 0.06", and grid pattern of 1/4" squares. -For other injury sites, other configurations may be appropriate. For arms, legs and thighs, for example, a larger screen, with a 1/2" grid pattern, may be more suitable. For the neck, chest and abdomen, a still larger screen may be desired. The thickness of the screen may vary so that it may be visualized on an X-ray when used with any part of the anatomy.

The grid screen 14 advantageously is formed with a strengthening border 15 about its periphery. Grid elements 16, 17 project longitudinally and transversely within the border, at a uniform spacing to form a calibrated grid of small, uniform squares. The grid elements 16, 17 desirably are as narrow as practicable, consistent with structural integrity, to maximize the unobstructed area while at the same time forming a readily visible image on the X-ray exposure.

To particular advantage, the grid-like screen is formed with a rectangular opening 18 in its central region, which is free

of the grid elements, to facilitate positioning the target point i relation to the point of entry or targeting point. The opening 1 is bisected by a central transverse grid element 17a, which extend across the full width of the screen and forms a positioning elemen 19. The positioning element desirably incorporates a targetin device 20, which may advantageously take the form of a smal diameter solid circle, which is placed directly over the point o entry. Alternatively, it may take the form of a small diamete circular eye. While not illustrated, a longitudinal grid element ma extend across the length of the opening, meeting the element 17 at the targeting device 20. This may give greater rigidity to the device.

Although the rectangular opening 18 may be centrall located, it is more advantageously offset slightly to one side. The irregularity in the positioning of the rectangle helps locate the foreign body with respect to a medial or lateral location. By medial we mean closer to the body, and by lateral away from the body. This enables the screen to be flipped over, from one side to the other, if desired, to obtain a more favorable positioning on the opening in relation to the injury site.

In the device specifically illustrated herein, a scree suitable for examination of hand and foot injuries is formed with a 12 by 24 grid structure, with a rectangular opening measuring 4 by 12 grid squares.

In the method of the invention, as exemplified by studies of the hand injury shown in the drawings, the grid screen 14 is initially supported directly over the hand, generally in the manner shown in Fig. 3. The screen can be supported directly on the hand by the surgeon or by application of adhesive tape. The targeting element 20 is carefully aligned with the point of entry or targeting point, sometimes referred to as a targeting mark. Thus the location of the screen is predetermined with respect to the

targeting mark. Where the entry wound is visible, as at 13 (Fig 5) in the illustration, the entry wound forms the targeting mark and the targeting circle or eye advantageously is aligned directl over the wound. The hand is then turned or rotated so that th screen directly abuts the X-ray film cassette 22. As seen in Fig 4, the X-ray apparatus has an X-ray source 24 with a principal axi 25 which emits a stream of X-rays 26 first passing through the han 10 containing the foreign body 12. The rays then penetrate th screen 14, and finally the cassette 22 containing unexposed film 8 The resulting X-ray image, incorporating the calibrated gri overlay image formed by the image of the screen, will precisel locate the position of the embedded foreign body 12 in a two dimensional sense, in relation to the grid overlay and to th targeting mark. After completion of the first image, the plane of th patient's hand is reoriented approximately 90°, relative to the X- ray apparatus (Fig. 6). To accomplish this, the hand is carefull turned with the targeting mark remaining in an imaginary, perpendicular line x extending upwardly from the targeting elemen 20. Accordingly, with respect to the grid-forming screen, th repositioned hand is oriented substantially at right angles to original orientation used in taking the first image. Thus the screen is moved to a second predetermined location with respect to the targeting mark. The second X-ray exposure taken in accordance with the procedure of the invention, results in an image (Fig. 7) corresponding to the illustration of Fig. 6. The foreign body 12 is precisely and measurably located with respect to the overlay image of the grid structure. This presents a two-dimensional relationship showing the depth of the foreign body.

As shown particularly in Fig. 6, in aligning the grid screen 14 for the second image, the targeting circle or eye must be aligned tangentially with the targeting mark, in this case the

entry wound 13. This enables accurate correlation of the images one with respect to the other, so that the location of the foreig object may be precisely pinpointed in three dimensions Accordingly, from the two images thus obtained, the surgeon ma quite precisely identify the optimum site for a surgical incisio and the required depth of the incision. Experience with the ne procedure establishes that the location and removal of the foreig object may be completed in far less time than with conventiona procedures and with correspondingly less trauma to the patient both in terms of surgical damage and of time and dosage o anesthesia.

The surgeon must work with the X-ray technician in th taking of the films so that as he visualizes the two films at righ angles to each other he can better correlate these films and kno exactly where to make the incision and how deep he must go in orde to come upon the foreign body.

In cases where the entry wound is healed or otherwis not detectable, the surgeon selects an appropriate point near th desired targeting site, potentially near the possible site o entry, and forms a targeting mark on the patient's skin with suitable permanent marking pen or surgical pen. The targetin circle or eye 20 is then aligned with the surgeon's mark to achiev desired alignment of the respective grid images.

In many instances, the location of the embedded foreig object will fall within the rectangular opening 18. This does no present a problem, however, as the adjacent grid lines may b manually or otherwise projected across the opening with require accuracy when performing analysis and measurements from th finished images. In certain cases, there are observationa advantages to be derived from positioning the rectangular openin to include the expected site of the foreign object. Very smal objects, in particular, will thus not be masked by the gri elements.

In certain circumstances it may prove necessary to tak an X-ray in which the screen is positioned between the body par and the X-ray source. For example, if a patient is not capable o being turned or rotated, the X-ray would be taken in this manner The X-ray source would then be rotated for a second x-ray. This i not the preferred method and may present certain difficulties. Th further the grid is from the film, the more likely the resultin grid pattern will be distorted. The surgeon will have to mak accommodations when planning the incision to compensate for th resulting distortion.

The procedure of the invention requires an absolut minimum of additional equipment. A suitable selection of simple grid screens, appropriate for various injury sites, is all that is necessary. Yet the benefits realized are extraordinary indeed. The removal of small bodies or objects, deeply embedded in the body can be extremely difficult and time consuming, even with the aid of conventional pre-operative X-ray images. With the device and procedure of the invention the object can be precisely located in the body, and an optimum incision site and surgical technique can be pre-planned. As a result, the time required to find and remove the object typically is reduced to a fraction of that conventionally needed. Further, the invention may be used for humans or animals.

The device and procedure of the invention are charac- terized by simplicity and economy, yet the results achieved are truly remarkable in terms of minimizing both surgical effort and patient trauma.

It should be understood, of course, that the specific form of the invention herein illustrated and described is intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.