WO2005081832A2

WO2005081832A2 - System for guiding a medical instrument

Info

Publication number: WO2005081832A2
Application number: PCT/US2005/004838
Authority: WO
Inventors: Randall Charles Blake
Original assignee: Randall Charles Blake
Priority date: 2004-02-26
Filing date: 2005-02-14
Publication date: 2005-09-09
Also published as: WO2005081832A3

Abstract

An arrangement for guiding a medical instrument (10) is described. The arrangement (10) includes (i) a bone fastener (12, 14), (ii) an external support assembly (16) attached to the bone fastener (12, 14) , and (iii) a template (18) having a number of apertures (44) defined therein. The template (18) is also attached to the external support assembly (16). An associated method is also described.

Description

SYSTEM FOR GUIDING A MEDICAL INSTRUMENT

CROSS REFERENCE TO RELATED APPLICATION ι This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Serial No. 60/547,995, filed February 26, 2004, the disclosure of which is hereby incorporated by reference.

TECHNICAL FIELD OF THE DISCLOSURE The present disclosure generally relates to a method and arrangement for guiding a medical instrument into the body of a patient. The present disclosure particularly relates to a method and arrangement for guiding a medical instrument into the body of a patient to undergo brachytherapy.

BACKGROUND OF THE DISCLOSURE Brachytherapy is an advanced cancer treatment and has been used in various types of malignancies including, for example, prostate, cervical, breast, endometrial as well as head and neck cancers. Generally, brachytherapy involves utilizing needles or catheters to place a radioactive material in or near the tumor itself, giving a high radiation dose to the tumor while reducing the radiation exposure in the surrounding healthy tissues. For example, high dose rate (HDR) brachytherapy involves placing thin catheters in or around a tumor to be treated. The catheters are then connected to an HDR afterloader. The HDR afterloader contains a highly radioactive material, such as an indium pellet, at the end of a wire and a radioactive pellet is pushed into each of the catheters under the control of a computer. In particular, the computer controls how long the pellet stays in each catheter, and where along the catheter it should pause to release its radiation. With a few well placed catheters in or around the tumor, HDR brachytherapy can provide a very precise treatment that takes only a few minutes. In addition, with HDR brachytherapy a series of treatments can be performed without leaving any radioactive materials in the patient's body. With respect to treating prostate cancer with HDR brachytherapy, typically this procedure includes using an ultrasonic device in conjunction with a template. In particular, the ultrasonic device includes a probe, which is inserted into the patient's rectum while the patient is lying on his back. The ultrasonic device is used to determine the exact location of the patient's prostate gland. With respect to the template, it typically includes a plurality of apertures arranged in a number of rows and columns. The catheters that deliver the radioactive material to the tumor are first inserted through the apertures defined in the template before being advanced into the body of the patient. It should be appreciated that the ultrasonic device and template cooperate to help ensure that when the catheters are inserted through the template and advanced into the patients body, they are located in the appropriate position in the prostate. Therefore, having the catheters located in the appropriate position in the prostate ensures that the appropriate areas of this organ will be exposed to radiation when the radioactive material is advanced into the body of the patient. Therefore, in light of the above discussion, it should be appreciated that the ability to appropriately locate needles or catheters in the body of a patient is an important aspect of performing brachytherapy, such as HDR brachytherapy. As such, an arrangement and/or method for enhancing one's ability to appropriately locate needles or catheters in the body of a patient is desirable.

SUMMARY OF THE DISCLOSURE An arrangement and/or method for guiding a medical instrument in accordance with the present disclosure comprises one or more of the following features or combinations thereof: An arrangement for guiding a medical instrument into the body of a patient may include one or more bone fasteners, such as, for example, a pair of bone screws. The arrangement may also include an external support assembly attached to the bone fastener(s). The external support assembly may include a connecting element attached to each of the bone fasteners. The external support assembly may also include an elongate fixation element, such as a rod or a post, attached to each of the bone fasteners via a connecting element. Each of the elongate fixation elements can also have another connecting element attached thereto, which in turn may have another elongate fixation element attached to each connecting element. The external support assembly can be made from any appropriate material utilized in fabricating medical devices. For example, the parts of the external support assembly can be made from a metal, such as surgical steel. The arrangement for guiding a medical instrument may also include a template attached to the external support assembly so that the template is mechanically attached to the bone fasteners. For example, the template may be secured to one or more of the elongate fixation elements. The template can have a number of apertures defined therein. For example, the apertures can be arranged so as to form a grid. Each of the rows or columns of the apertures can be associated with a number or a letter. The template can also include a front portion, an intermediate portion, and a rear portion. The front portion of the template can be attached to the rear portion with the intermediate portion interposed the front portion and the rear portion. The template may include an adjustment screw advanced through the intermediate portion, so that the turning of the adjustment screw moves the intermediate portion relative to the front portion and the rear portion. In addition, the template can have one or more channels defined therein. These channels can be configured to receive the elongate fixation elements of the external support assembly and thereby attach the template to the external support assembly, and thus mechanically attach the template to the bone fasteners. Each channel can be in communication with a set screw to lock the elongate fixation element in the channel. The template may be made from any appropriate material for a medical device, for example, a polymeric material such as plastic. The above discussed components of an arrangement for guiding a medical instrument into the body of a patient can be included in a kit. For example, the aforementioned kit can include a bone fastener, an external support assembly, and a template. Whereupon assembly of the components of the kit results in the template being mechanically coupled to the bone fastener. It should be appreciated that an arrangement for guiding a medical instrument into the body of a patient of the present disclosure can be employed to guide catheters into the interior of the body of a patient undergoing brachytherapy, such as HDR brachytherapy. For example, one embodiment of a method of utilizing an arrangement of the present disclosure in brachytherapy can include (i) attaching one or more bone fasteners to a bone of a patient, (ii) attaching an external support assembly to the bone fastener(s), (iii) attaching a template to the external support assembly so that the template is mechanically coupled to the bone fastener(s). In a particular example, an arrangement of the present disclosure can be attached to the pelvic bone of a patient undergoing brachytherapy for prostate cancer, hi utilizing the arrangement of the present disclosure to perform brachytherapy for prostate cancer, the arrangement is positioned relative to the pelvic bone of the patient so that the template is located between the legs of the patient and adjacent to the patient's perineum. Once positioned in such a manner, catheters can be guided into the appropriate location in the prostate of the patient by first advancing them through the apertures defined in the template and then inserting them into the patient's prostate. Thereafter, a radioactive material is advanced into the catheters and into the body of the patient, with, for example, an afterloader, so as to expose the cancerous tissue to radiation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view of an exemplary template of the present disclosure; FIG. 2 is perspective view of an exemplary external support assembly attached to a pelvis; FIG. 3 is an assembled perspective view of the exemplary template of FIG. 1; FIG. 4 is a perspective view of the exemplary external support assembly attached to the pelvis shown in FIG. 2, with the template of FIG. 3 secured thereto; FIG. 5 is a fragmentary view of the template and external support assembly of FIG. 4 secured to a patient undergoing brachytherapy for prostate cancer; FIG. 6 is a view similar to FIG. 5, but showing the conduits detached from the catheters; FIG. 7 is a perspective view of the template and external support assembly of FIG. 4 secured to a patient by a pair of bone fasteners (note that the template is not visible since it is located adjacent to the patient's perineum); and FIG. 8 is a schematic representation of the template of FIG. 3 working in conjunction with an ultrasonic device. DETAILED DESCRIPTION OF THE DISCLOSURE While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. Now referring to FIGS. 2 and 4, there is illustrated an exemplary arrangement for guiding a medical instrument 10 of the present disclosure attached to a pelvic bone 28. However, it should be appreciated that arrangement 10 can be attached to any bone as required for the appropriate guiding of a medical instrument, such as a catheter. The arrangement 10 includes a pair of bone fasteners 12 and 14 which can be, for example, bone screws. Bone screws which can be utilized in the present arrangement 10 are commercially available from, for example, Synthes (U.S.A.), located in Paoli, Pennsylvania. The arrangement 10 also includes an external support assembly 16 and a template 18 having a number of apertures 44 defined therein. (Note that template 18 is not -shown in FIG. 2 for clarity of description.) As shown in FIG. 2, external support assembly 16 includes four elongate fixation elements 24, 32, 26, and 36, configured, for example, as rods or posts. Elongate fixation elements 24, 32, 26, and 36 can be fabricated from any appropriate material which can be utilized in a medical instrument, for example surgical steel. External support assembly 16 also includes four connecting elements 20, 22, 30, and 34, which can be, for example, clamps configured to (i) be attached to bone fasteners 12 and 14 and (ii) hold elongate fixation elements 24, 32, 26, and 36 in place. Clamps which can be utilized in the present arrangement 10 are commercially available from, for example, Synthes (U.S.A.). In one embodiment, external support assembly 16 is constructed and attached to bone 28 in the following manner. As shown, bone fasteners 12 and 14 are secured to bone 28, for example, screwed into bone 28. Connecting element 20 is attached to bone fastener 12. Elongate fixation element 24 is then attached to connecting element 20 so that elongate fixation element extends outwardly from bone fastener 12 in a perpendicular manner. Connecting element 22 is then attached to elongate fixation element 24 so that connecting element 22 is paced apart from connecting element 20 along the longitudinal axis of elongate fixation element 24. Elongate fixation element 26 is then secured to coimecting element 22 so that elongate fixation element 26 extends outwardly from elongation fixation element 24 in a perpendicular manner. As shown in FIGS. 2 and 4, bone fastener 14 is attached to bone 28 so that it is adjacent to bone fastener 12.

Connecting elements 30 and 34 and elongate fixation elements 32 and 36 are then mechanically coupled to bone fastener 14 in an identical manner as described above. As shown in FIG. 4, and discussed in greater detail below, template 18 is attached to elongate fixation elements 26 and 36 so that template 18 is mechanically coupled to bone fasteners 12 and 14. Now referring to FIGS. 1 and 3, template 18 includes a front portion 38, an intermediate portion 40, and a rear portion 42. As mentioned above, each of these portions 38, 40, and 42 have a number of apertures 44 defined therein. In particular, the apertures 44 defined in each of these portions 38, 40, and 42 are arranged so as to form a grid 46. In addition, each row or column of the grid 46 of apertures is associated with a number or a letter. Front portion 38 is attached to rear portion 42 with intermediate portion 40 being interposed front portion 38 and rear portion 42. hi particular, front portion 38 is secured to rear portion 42 via a plurality of plugs 52 that extend outwardly from rear portion 42 and are interference fit into a plurality of corresponding holes 54 defined in front portion 38. It should also be appreciated that front portion 38 can also be secured to rear portion 42 with a number of screws. When front portion 38, intermediate portion 40, and a rear portion 42 are secured together in the above described manner, the apertures defined in each portion are aligned so that a medical instrument, such as a catheter, can be inserted into one of the apertures and advanced completely through template 18. Once a medical instrument is advanced completely through template 18 in the above described manner, an adjustment screw 56 can be screwed into a hole 58 defined in a top shoulder portion 60 of intermediate portion 40 to prevent the movement of the medical instrument relative to template 18. In particular, advancing adjustment screw 56 into hole 58 after template 18 is assembled as described above results in the end of adjustment screw 56 being urged against surface 62 (see FIG. 1) of front portion 38. Urging adjustment screw 56 against surface 62 results in intermediate portion 40 being moved relative to front portion 38 and rear portion 42 in the direction indicated by arrow 64 as shown in FIG. 3. Moving intermediate portion 40 in this manner results in the apertures 44 defined in intermediate portion 40 being misaligned to a certain degree with the apertures 44 defined in front portion 38 and rear portion 42. Accordingly, having a medical instrument, such as a catheter, positioned through an aperture 44 when intermediate portion 40 is misaligned relative to the apertures 44 defined in front portion 38 and rear portion 42 results in the medical instrument being locked into position relative to template 18. In other words, movement of the medical instrument relative template 18 is prevented. For example, the medical instrument, such as a catheter, is prevented from sliding in and out of the aperture 44. Still referring to FIGS. 1 and 3, front portion 38 has a channel 66 defined in each of its sides 68 (note that only one channel 66 is shown in FIGS. 1 and 3). Each side 68 of template 18 has a screw hole defined 70 therein (see FIG. 1) so that screw hole 70 is in communication with channel 66. Template 18 also includes a pair of set screws 72 which are screwed into the pair of screws hole 70. As shown in FIG. 4, channels 66 are configured to receive elongate fixation elements 26 and 36. Once elongate fixation elements 26 and 36 are positioned in channels 66, set screws 72 are screwed into the pair screw holes 70 so that set screws 72 are urged against elongate fixation elements 26 and 36. Urging set screws 72 against elongate fixation elements 26 and 36 attach template 18 to external support assembly 16, and thus mechanically couples template 18 to bone fasteners 12 and 14. Now turning to FIG. 7, arrangement 10 is shown attached to a patient 50 that is going to undergo brachytherapy for prostate cancer, h particular, bone fasteners 12 and 14 are secured to the pelvic bone of patient 50 as described above. In addition, external support assembly 16 is constructed and attached to bone fasteners 12 and 14 in the manner described above. Furthermore, template 18 is attached to elongate fixation elements 26 and 36 in the manner described above. Accordingly, it should be appreciated that securing arrangement 10 to patient 50 in the above described manner results in template 18 being located between the legs 74 and 76 of patient 50, and adjacent the perineum 78 of patient 50 (note that perineum 78 is not shown in FIG. 7, see FIGS. 5 and 6). As schematically shown in FIG. 8, template 18 is directly or indirectly mechanically coupled to an ultrasonic device 80 via, for example, a number of clamps or brackets. The ultrasonic device is then used in a well known manner to image the prostate of patient 50 so that the location of template 18 relative to the prostate is correct, hi particular, template 18 should be located so that when catheters 48 are advanced through the selected apertures 44 of template 18, and then further advanced through the apertures 44, an end of each catheter 48 passes through perineum 78 of patient 50 and is advanced into the interior of the patient's 50 body. In addition, template 18 should be located relative to the patient's 50 prostate so that after advancing the catheter 48 into the patient's 50 body a portion of the catheter is located at an appropriate position relative to the cancerous tissue in the prostate. It should be appreciated that to move template 18 around to position it in the correct location, the connecting elements 20, 22, 30, and 34 of external support assembly 16 can be loosened so that the elongate fixation elements 24, 26, 32, and 36 can be moved relative to one another, and moved relative to perineum 78. In addition, set screws 72 can be loosened so that template 18 can be moved relative to external support assembly 16 and perineum 78. However, it should be appreciated that once template 18 located in the correct position, connecting elements 20, 22, 30, and 34 and set screws 72 are tightened to prevent template 18 from moving out of that position, hi particular, template 18 is mechanically coupled to pelvic bone 28 and thus locked or fixed in the correct position relative to the patient's 50 prostate. As shown in FIG. 6, as indicated above, once template 18 is fixed in the appropriate position a number of catheters 48 are advanced through the apertures 44 of template 18 and into the interior of the patient's 50 body. Also as indicated above, the catheters 48 are located in an appropriate position relative to cancerous tissue in the prostate with, for example, the help of ultrasonic device 80. As shown in FIG. 5, once catheters 48 are positioned correctly as described above, each catheter 48 is coupled to a delivery tube 82. Each delivery tube 82 is operatively coupled to a HDR afterloader (not shown) in a well known manner. The afterloader delivers and advances the radioactive material through each catheter 48 and into the patient's 50 body in a well known manner so that the radioactive material is located near the cancerous tissue of the prostate for a predetermined time period. After the cancerous tissue has been exposed to the radioactive material for the predetermined time period, the afterloader removes the radioactive material from the patient's body and the delivery tubes 82 are decoupled from the catheters 48. A certain amount of time passes and the cancerous tissue can be exposed to the radiation once again if required. It should be appreciated that during the time period between being exposed to the radioactive material, arrangement 10 is still attached to the body of patient 50 with template 18 located in the appropriate position. Accordingly, the next time patient 50 undergoes a treatment the radioactive material can be advanced to the correct location in the patient's 50 body without having to first reposition the template 18 in the correct location. While the above disclosure is directed to the use of arrangement 10 in HDR brachytherapy to treat prostate cancer, it is contemplated that it can be utilized in other situations where a medical instrument needs to be guided by a template. For example, it is contemplated that arrangement 10 may be utilized in other types of brachytherapy treatments, for example, including, but not limited to, treating cervical, breast, endometrial as well as head and neck cancers. While the invention has been illustrated and described in detail in the foregoing description, such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.

Claims

CLAIMS:

1. An arrangement for guiding a medical instrument, the arrangement comprising: a first bone fastener; an external support assembly attached to the bone fastener; and a template having a number of apertures defined therein, wherein the template is attached to the external support assembly.

2. The arrangement of claim 1, wherein: (i) the external support assembly includes a first connecting element attached to the first bone fastener, a first elongate fixation element attached to the first connecting element, a second connecting element attached to the first elongate fixation element, a second elongate fixation element attached to the second connecting element, and (ii) the template is attached to the second elongate fixation element.

3. The arrangement of claim 2, further comprising a second bone fastener, wherein: (i) the external support assembly further includes a third connecting element attached to the second bone fastener, a third elongate fixation element attached to the third connecting element, a fourth connecting element attached to the third elongate fixation element, and a fourth elongate fixation element attached to the fourth connector element, and (ii) the template is attached to the fourth elongate fixation element.

4. The arrangement of claim 2, wherein: the first bone fastener is a bone screw.

5. The arrangement of claim 1, wherein: the template includes (i) a front portion, (ii) an intermediate portion, and (iii) a rear portion, and the front portion is attached to the rear portion, and the intermediate portion is interposed the front portion and the rear portion.

6. The arrangement of claim 1, wherein the apertures defined in the template are arranged in a grid.

7. A medical device for guiding catheters used in brachytherapy, the medical device comprising: a bone screw; an external support assembly attached to the bone screw; and a template having a plurality of apertures defined therein, wherein the apertures are arranged in a grid, the template being attached to the external support assembly.

8. The device of claim 7 wherein: (i) the external bone fixation assembly includes a first clamp attached to the bone screw, a first post attached to the first clamp, a second clamp attached to the first post, and a second post attached to the second clamp, and (ii) the template is attached to the second post.

9. A kit of parts for guiding a medical instrument, the kit comprising: a bone fastener; an external support assembly; and a template having a number of apertures defined therein, wherein when the parts of the kit are assembled, the external support assembly mechanically couples the bone fastener to the template.

10. The kit of claim 9, wherein: the bone fastener is a bone screw.

11. The kit of claim 9, wherein: (i) the external support assembly includes a first clamp configured to be attached to the bone fastener, a first post configured to be attached to the first clamp, a second clamp configured to be attached t the first post, and a second post configured to be attached to the second clamp, and (ii) the template is configured to be attached to the second post.

12. The kit of claim 9, wherein: the apertures defined in the template are arranged in a grid.

13. A method of guiding the advancement of a catheter into the body of a patient having a first leg, a second leg, and a perineum, the method comprising: attaching a bone fastener to a bone of the patient; attaching an external support assembly to the bone fastener; and attaching a template having a number of apertures defined therein to the external support assembly so that the template is mechanically coupled to the bone fastener.

14. The method of claim 13 , wherein: attaching a bone fastener to a bone of the patient includes screwing a bone screw into the bone of the patient.

15. The method of claim 13 , wherein: attaching a bone fastener to the bone of the patient includes attaching the bone fastener to the pelvic bone of the patient.

16. The method of claim 13 , further comprising: advancing a catheter through an aperture defined in the template and into the interior of the body of the patient.

17. The method of claim 16, further comprising: advancing a radioactive material through the catheter and into the interior of the body of the patient.

18. The method of claim 13, further comprising: positioning the template so that the template is located (i) between the first leg and the second leg and (ii) adjacent the perineum.

19. A method of performing brachytherapy, the method comprising: attaching a bone screw to a bone of a patient; attaching an external support assembly to the bone screw; attaching a template having a number of apertures defined therein to the external support assembly so that the template is mechanically coupled to the bone screw; advancing a catheter through an aperture defined in the template and into the interior of the body of the patient; and advancing a radioactive material through the catheter and into the interior of the body of the patient.

20. A method of treating a patient with prostate cancer, the method comprising: attaching a bone screw to the pelvic bone of the patient; attaching an external support assembly to the bone screw; attaching a template having a number of apertures defined therein to the external support assembly so that the template is mechanically coupled to the bone screw; positioning the template so that the template is located adjacent to the perineum of the patient; advancing a catheter through an aperture defined in the template and into the prostate of the patient; and advancing a radioactive material through the catheter and into the prostate of the patient.