SURGICAL ACCESS RETRACTOR

Abstract

There is provided a patient specific access retractor for use in surgery, for example, minimally invasive spinal surgery. There are also provided methods of using the access retractor in surgery.

Claims

1. A surgical access retractor for maintaining an enlarged surgical corridor, said retractor having a length sufficient to span from a skin surface through to a region of surgical interest, said retractor having at least one portion shaped to match with the region of surgical interest, wherein the shape of said portion is, at least in part, based on patient specific medical imaging.

2. A surgical access retractor according to claim 1, wherein the length sufficient to span from a skin surface through to a region of surgical interest is determined by patient specific medical imaging.

3. A surgical access retractor according to claim 1, wherein the region of surgical interest is an anatomical body, such as a vertebral body.

4. A surgical access retractor according to claim 1, wherein the region of surgical interest is a pedicle.

5. A surgical access retractor according to claim 1, wherein the shaped portion of the retractor comprises one or more fixation means for securing the retractor to the region of surgical interest.

6. A surgical access retractor according to claim 1, wherein the retractor comprises a lip on the top face which, in use, is placed on patient's skin.

7. A surgical access retractor according to claim 1, wherein the retractor comprises at least one fixation means for securing the retractor to a patient's skin.

8. A surgical access retractor according to claim 6, wherein the angle of the lip is customised based on patient medical imaging.

9. (canceled)

10. (canceled)

11. (canceled)

12. A surgical access retractor according to claim 1, wherein the retractor comprises antimicrobial substances or surface coatings to reduce the risk of infection.

13. A surgical access retractor according to claim 1, wherein the retractor comprises radio-opaque markers to allow verification of positioning by way of image intensification.

14. (canceled)

15. A surgical access retractor according to claim 1, wherein, in use, electrophysiological sensors are placed beside the access retractor in preset locations to facilitate neural monitoring in the working area.

16. A surgical access retractor according to claim 1, wherein the retractor comprises ancillary channels to allow suction of fluid from an internal aperture of the device or irrigation of fluid into an internal aperture of the device.

17. A method for designing a patient specific access retractor comprising the steps of: a) determining one or more trajectories from a region of surgical interest to the skin surface of a patient using preoperative medical imaging; b) determining the morphology of the region of surgical interest using preoperative medical imaging; and c) designing the access retractor, said retractor having a length sufficient to span from a skin surface through to the region of surgical interest, said retractor having at least one portion shaped to dock with the region of surgical interest, wherein the shape of said portion is based, at least in part, on patient specific medical imaging.

18. A method for manufacturing a patient specific access retractor comprising the steps of: a) determining one or more trajectories from a region of surgical interest to the skin surface of a patient using preoperative medical imaging; b) determining the morphology of the region of surgical interest using preoperative medical imaging; c) designing the access retractor, said retractor having a length sufficient to span from a skin surface through to the region of surgical interest, said retractor having at least one portion shaped to dock with the region of surgical interest, wherein the shape of said portion is based, at least in part, on patient specific medical imaging; and d) manufacturing the access retractor.

19. A method according to claim 17, wherein the region of surgical interest is an anatomical body, such as a vertebral body.

20. A method according to claim 19, wherein the vertebral body is a pedicle.

21-30. (canceled)

31. A method for accessing a region of surgical interested comprising the steps of: a) providing a retractor according to claim 1; b) docking the shaped portion of the retractor via a surgical corridor to the region of surgical interest; and c) fixing said retractor to the region of surgical interest.

32. A method according to claim 31, wherein prior to docking the shaped portion of the retractor to the region of surgical interest one or more dilators are utilized to increase the width of the surgical corridor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] FIG. 1(a) is a plan view of an access retractor according to an embodiment of the present disclosure.

[0066] FIG. 1(b) is a plan view of an access retractor according to an embodiment of the present disclosure.

[0067] FIG. 1(c) shows a cutaway of an access retractor according to an embodiment of the present disclosure.

[0068] FIG. 1(d) is a side elevation of an access retractor according to an embodiment of the present disclosure.

[0069] FIG. 1(e) shows a section through plane A-A of the access retractor of FIG. 1(a) according to an embodiment of the present disclosure.

[0070] FIG. 1(e) shows a side elevation of an access retractor according to an embodiment of the present disclosure.

[0071] FIGS. 2 to 5 show a computer designed access retractor in use according to an embodiment of the present disclosure.

[0072] FIG. 6 is an enlargement of FIG. 1(c).

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0073] Before the present devices and/or methods are disclosed and described, it is to be understood that unless otherwise indicated this disclosure is not limited to specific devices, components, designs, methods, or the like, as such may vary, unless otherwise specified. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0074] It must also be noted that, as used in the specification and the appended claims, the singular forms ‘a’, ‘an’ and ‘the’ include plural referents unless otherwise specified. Thus, for example, reference to ‘a guide wire’ may include more than one guide wires, and the like.

[0075] Disclosed herein are advantageous devices and methods for performing surgery, particularly spinal fusion surgery.

[0076] In an exemplary embodiment a patient specific access retractor is provided. Once the depth of tissue to be accessed by the retractor is known from patient medical imaging, standard design may be applied to the external or top part of the retractor. This may extend to approximately 80% of the depth of the access retractor. The final approximately 20% may be designed in a specific way to contour match the morphology of the patient's anatomy and in particular, the region of surgical interest.

[0077] A guidance aperture may be within the retractor where a Nitinol K-wire is used to localise the retractor to the patient specific anatomy. The guidance aperture may also allow placement of a cannulated screw to secure the retractor to the patient's spine. Within the guidance aperture may be specially designed grooves, which facilitate placement of instruments in locations within the working area of the access retractor. Such grooves may be used to place mark-to-mark osteotomy lines on the patient's bone and then guide instruments into the interbody space. The access retractor may also comprise an attachment for a Nitinol K-wire on the rosteral side of the intervertebral disc to be operated on. This facilitates attachment of the access retractor to the patient. The access retractor may have apertures or instrument guides such that a fibre optic light source may be attached. The access retractor may have a guide or facility for the use of diathermy at the base of the retractor. The customised portion of the retractor may have diathermy points or a guide for the use of such points in the equipment such that the tissue can be cauterised.

[0078] In order to evolve the manufacturing procedure to a greater level of ergonomic efficiency, safety and best possible patient outcomes, three-dimensional printing technology has been used to facilitate these outcomes.

[0079] Three-dimensional printing is a process whereby layer based polymerisation of a resin or powder is used to produce a solid object. This technology has been applied to producing solid replicas of anatomy which has been captured by medical imaging.

[0080] Three-dimensional printing technology has been used extensively in computerised design product development prototyping and more recently direct manufacturing of objects. It has been possible to integrate computer design and anatomical biomodeling information to provide customised prosthetic implants for the human body. This disclosure uses rapid prototyping technology to facilitate interbody fusion by way of the minimally invasive transforaminal interbody fusion technique. Three-dimensional bench top printing has been integrated with diagnostic surgical planning, surgical navigation and by way of patient specific minimally invasive access retractors.

[0081] The patient specific access retractor may also be used for harvesting bone graft. A second retractor may be manufactured by three-dimensional printing to dock on the iliac crest or other part of the skeleton to harvest bone graft. In this embodiment, a vector is created from either the right or left iliac crest which crosses the skin at the same point, if possible, as one of the vectors identifying the pedicle of the selected vertebra. Alternatively, a vector exiting at a separate point would be another option. The depth of tissue from the surface to the iliac crest or bone donor site is determined. The retractor is again contour matched to the surface of the iliac crest or bone donor site and the length and diameter of the retractor is then constructed in three-dimensional design software. The retractor incorporates a guide for placement along a K-wire that has been fixed to the iliac crest bone donor site. The retractor is then manufactured by way of three-dimensional printing in a bio-compatible material. At the time of surgery, the surgeon places a Jamshidi needle into the iliac crest or suitable bone donor site and places a K-wire. The K-wire is then used to guide the retractor to the iliac crest or bone donor site and a cannulated screw is then used to secure the retractor to the crest. The retractor may act to guide instruments to harvest bone graft by way of specific channels and grooves within the retractor.

[0082] Referring to FIG. 1(a), access retractor (1) is illustrated. The retractor has a fixation point (2), located on the shaped portion of the retractor, for fixing to an anatomical body and guides (3) to facilitate, for example, the introduction of instruments. An aperture (4) on the retractor lip is available to secure the retractor to the patient's skin.

[0083] Referring to FIG. 1(b), a guide (3) for instrument introduction is highlighted.

[0084] Referring to FIGS. 1(c) and 6, the portion (5) of retractor (1) is shaped based on patient specific information so as to dock with a region of surgical interest.

[0085] Referring to FIG. 1(d), lip (6) is angled based on patient specific medical imaging.

[0086] FIG. 1(e) depicts a section A-A through retractor (1) of FIG. 1(a). The section shows fixation point (2) and other shaped structure (7).

[0087] FIG. 1(f) indicates the length of the retractor to be 60 mm, that is, the length from the region of surgical interest to the surface of the skin.

[0088] FIGS. 2 to 5 illustrate various computer simulations of retractor (1) fixed in place on vertebral body (8). FIG. 3 shows a cutaway of the tissue surrounding the vertebral body with retractor (1) fixed in place. FIG. 4 is similar to FIG. 3 but the tissue (9) is now illustrated with the lip (6) of the retractor is located external to the tissue structure. FIG. 5 shows retractor (1) fixed in place on a vertebral body (8) with the shaped portion (5) docking with the vertebral body.

[0089] While the foregoing description has focused on spinal surgery, it is contemplated that the retractors and methods described herein may find use in a wide range of surgical applications. Thus, where it is desired to insert a screw or pin into bone in a minimally invasive manner, or otherwise to access a surgical target site via an instrument, the retractors and dilators of the present disclosure may be used.

[0090] It is to be understood that while the present disclosure has been described in conjunction with the specific embodiments thereof, the foregoing description is intended to illustrate and not limit the scope of the disclosure. Other aspects, advantages and modifications will be apparent to those skilled in the art to which the disclosure pertains. Therefore, the above examples are put forth so as to provide those skilled in the art with a complete disclosure and description of how to make and use the disclosed devices, and are not intended to limit the scope of the disclosure.

[0091] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited.

[0092] All documents cited are herein fully incorporated by reference for all jurisdictions in which such incorporation is permitted and to the extent such disclosure is consistent with the description of the present disclosure.