# US 2021/0275218 A1 · Expanders For Rod Retraction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0275218 A1 - Document ID: US20210275218A1 - Status: Published application - Kind: A1 - Application number: 17/236,356 - Filed: 2021-04-21 - Published: 2021-09-09 - Earliest claimed: 2017-08-17 - Assignees: Stryker European Operations Holdings LLC - Applicants: Stryker European Operations Holdings LLC - Inventors: Andrew Edward Ehlers; Steven F. Krause; Charles L. Bush, JR. - Web page: https://patentgrep.com/patent/US20210275218A1 ## CPC - A61B 17/3439: {with means for changing the inner diameter of the cannula, e.g. expandable (A61B17/3423, A61B17/3431 take precedence; catheters A61M25/0662)} - A61B 17/0206: {with antagonistic arms as supports for retractor elements} - A61B 17/0218: {for minimally invasive surgery (A61B17/0281, A61B17/0469, A61B17/12013, A61B17/1285, A61B17/29, A61B17/320016 take precedence)} - A61B 17/025: {Joint distractors} - A61B 2017/0256: {for the spine} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract In one embodiment, an expander set includes a first and second expander. The first expander includes an outer surface having a first engagement feature and a groove and the second expander includes an inside surface having a second engagement feature adapted to engage with the first engagement feature. The inside surface of the second expander is shaped to correspond to a portion of the outer surface of the first expander. Additionally, the groove on the outer surface of the first expander is sized and shaped to accommodate a rod of a retraction system such that when the first expander is advanced within the retraction system, the rod remains within the groove. When the first and second expanders are engaged with one another, they define an oblong cross-section. ## Claims ### Claim at position 1 1-20. (canceled) ### Claim 21 An expander for use in forming a surgical portal comprising: a first member; and a second member slidably attached to the first member, wherein the second member is slidable with respect to the first member to change a cross-section of a portion of the expander, wherein the second member forms part of an outer surface of the expander, and wherein the expander has a maximum cross-section that includes both the first member and the second member. ### Claim 22 (depends on 21) The expander of claim 21, wherein a second surface of the second member is flush with a first surface of the first member, the second surface being linearly slidable relative to the first surface to change the cross-section of the portion of the expander. ### Claim 23 (depends on 21) The expander of claim 21, wherein the first member includes a protrusion contacting a moving part of the second member. ### Claim 24 (depends on 23) The expander of claim 23, wherein the second member includes a slot such that the protrusion of the first member is disposed within the slot, a position of the protrusion relative to an end of the slot changing with sliding of the second member relative to the first member. ### Claim 25 (depends on 21) The expander of claim 21, wherein the second member includes a sliding portion and a lateral portion, the lateral portion translating laterally when the sliding portion slides with respect to the first member. ### Claim 26 (depends on 21) The expander of claim 21, wherein the first member tapers over its length and the second member tapers over its length. ### Claim 27 (depends on 21) The expander of claim 21, wherein the first member is biased in a closed position such that sliding the second member toward a leading end of the first member causes the leading end of the first member to expand laterally. ### Claim 28 An expander extending from a trailing end to a leading end and for use in providing surgical access, the expander comprising: a first member; and a second member attached to the first member, the second member being translatable relative to the first member such that translation of the second member relative to the first member causes a change in a cross-section of the expander over at least part of the expander, wherein the second member is translatable to a first position relative to the first member so that at least part of the trailing end of the expander includes the second member. ### Claim 29 (depends on 28) The expander of claim 28, wherein the second member is translatable to a second position relative to the first member so that the expander has a maximum cross-sectional dimension adjacent to the leading end of the expander. ### Claim 30 (depends on 28) The expander of claim 28, wherein when the second member is in the first position relative to the first member, the expander has a maximum cross-sectional dimension at the trailing end of the expander. ### Claim 31 (depends on 28) The expander of claim 28, wherein the expander has a maximum cross-sectional dimension at a first location between the trailing end and the leading end such that at least part of an outward facing surface of the expander at the first location is defined by an outward facing surface of the second member. ### Claim 32 (depends on 28) The expander of claim 28, wherein when the second member is translated away from the leading end of the expander, a cross-sectional dimension of the expander at the leading end of the expander increases. ### Claim 33 (depends on 28) The expander of claim 28, wherein the expander has a maximum outer dimension at a first minimum distance from the leading end of the expander when the second member is in the first position, the maximum outer dimension being at a second minimum distance from the leading end of the expander when the second member is translated toward the leading end of the expander, the second minimum distance being less than the first minimum distance. ### Claim 34 (depends on 28) The expander of claim 28, wherein a second surface of the second member is flush with a first surface of the first member, the second surface being linearly translatable relative to the first surface to change the cross-section over the at least part of the expander. ### Claim 35 An expander for providing surgical access comprising: a first member with a first surface; and a second member slidably attached to the first member, the second member having a second surface flush with the first surface over at least part of a length of the second member, wherein the second member is slidable with respect to the first member to change a cross-section of a portion of the expander. ### Claim 36 (depends on 35) The expander of claim 35, wherein the second member is slidable with respect to the first member along a longitudinal axis of the expander. ### Claim 37 (depends on 36) The expander of claim 36, wherein the second member is slidable with respect to the first member to change an extent of overlap between the first surface and the second surface. ### Claim 38 (depends on 35) The expander of claim 35, wherein the length of the second member is a maximum dimension of the second member. ### Claim 39 (depends on 35) The expander of claim 35, wherein the second member is rotatable about a longitudinal axis of the expander. ### Claim 40 (depends on 35) The expander of claim 35, wherein the cross-section of the portion of the expander increases uniformly along a length of the expander in conjunction with sliding of the second member away from an insertion end of the expander.