Expandable medical access device
View Patent ↗An access device comprises a thin-walled sheath that is insertable into a patient through a small surgically created incision. The incision may be created using a cutdown or a percutaneous method such as that known as the Seldinger technique. Once inserted and advanced to the target surgical site, the sheath is selectively, and controllably, expanded to a desired diameter. The thin wall of the sheath is fabricated from a rectangular piece of material such as metal or plastic with two cut edges. The rectangular piece of metal or plastic is rolled tightly to create the small diameter configuration that is inserted into the patient. A cam or control member is affixed to the innermost edge of the rectangular piece of metal or plastic. The control member extends to the proximal most portion of the sheath. By rotating the control member, the operator causes the thin wall piece of rolled material to unfurl into a larger or smaller diameter, depending on the direction of rotation. A mechanical lock at the distal end of the sheath permits the control member to be selectively constrained from rotation and thus lock the sheath diameter in place.
1. An access sheath adapted for providing minimally invasive surgical access, comprising:
a tubular member formed from a rolled sheet of thin walled material, the thin walled material including an inner surface, an outer surface, an inner portion including an inner edge and an outer portion including an outer edge;
a first component comprising a longitudinal member, the longitudinal member coupled to the inner portion of the thin walled material;
a second component comprising a static rod coupled to the outer portion of the thin walled material and a tubular hub immovably coupled to the proximal end of the static rod; and
a knob attached to the longitudinal member of the first component, the knob configured to rotate the first component with respect to the second component, wherein rotation of the first component with respect to the second component uniformly unwinds the rolled sheet of thin walled material of the tubular member from a first configuration comprising a lumen of uniform diameter within overlapping layers of the thin walled material to a second configuration comprising a lumen of greater uniform diameter within fewer overlapping layers of the thin walled material.
2. The access sheath of claim 1 , further comprising a containment layer positioned on the outside of the rolled sheet.
3. The access sheath of claim 1 , further comprising a containment layer positioned on the inside of the rolled sheet.
4. The access sheath of claim 1 further comprising a seal at a proximal end of the tubular hub.
5. The access sheath of claim 1 further comprising a lock configured to constrain the rotation of said knob with respect to said tubular hub.
6. The access sheath of claim 5 wherein the lock is a ratchet mechanism.
7. The access sheath of claim 1 wherein said second configuration comprises at least two overlapping layers.
8. The access sheath of claim 1 wherein reverse rotation of the first component with respect to the second component winds the rolled sheet of thin walled material of the tubular member from said second configuration to said first configuration.
9. The access sheath of claim 1 further comprising a removable obturator.
10. The access sheath of claim 9 , wherein the removable obturator comprises a guidewire lumen extending from the proximal end to the distal end of the obturator.
11. An access sheath adapted for providing minimally invasive surgical access to a body, comprising:
a tubular member formed from a rolled sheet, the rolled sheet comprising axially distributed segmented sections of thin walled material coupled together by connectors, each of the segmented sections of the thin walled material including an inner surface, an outer surface, an inner portion including an inner edge and an outer portion including an outer edge;
a first component comprising a flexible longitudinal member, the flexible longitudinal member coupled to the inner portions of each of the segmented sections of the thin walled material;
a second component comprising a static rod coupled to the outer portions of each of the segmented sections of the thin walled material and a tubular hub coupled to the proximal end of the static rod; and
a winding knob attached to the longitudinal member of the first component, the winding knob configured to rotate the longitudinal member with respect to the static rod, wherein rotation of the longitudinal member with respect to the static rod unwinds the rolled sheet of thin walled material of the tubular member from a first configuration comprising overlapping layers of the thin walled material to a second configuration comprising fewer overlapping layers of the thin walled material.