# US 11,896,291 B2 · Electrically-insulative shafts, methods of manufacturing electrically-insulative shafts, and energy-based surgical instruments incorporating electrically-insulative shafts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,896,291 B2 - Document ID: US11896291B2 - Status: Granted - Kind: B2 - Application number: 16/024,989 - Filed: 2018-07-02 - Published: 2020-01-02 - Granted: 2024-02-13 - Earliest claimed: 2018-07-02 - Assignees: Covidien LP - Applicants: Covidien LP - Inventors: Zachary S. Heiliger - Web page: https://patentgrep.com/patent/US11896291B2 ## CPC - A61B 18/1445: {at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod} - A61B 17/2909: {Handles} - A61B 17/295: combined with cutting implements - A61B 2017/2902: {characterized by features of the actuating rod} - A61B 2017/294: {Connection of actuating rod to jaw, e.g. releasable} - A61B 2018/00077: {high, i.e. electrically conducting} - A61B 2018/00083: {low, i.e. electrically insulating} - A61B 2018/00607: {Coagulation and cutting with the same instrument} - A61B 2018/1455: {having a moving blade for cutting tissue grasped by the jaws} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract An electrically-insulative shaft for an energy-based surgical instrument includes an outer tube formed from an electrically-insulative material, an inner tube formed from an electrically-insulative material, and an intermediate tube disposed between the outer and inner tubes. The intermediate tube is formed from an electrically-conductive material. Distal ends of the outer and inner tubes extend beyond a distal end of the intermediate tube and are joined to one another to enclose the distal end of the intermediate tube therebetween. ## Claims ### Claim 1 An electrically-insulative shaft for an energy-based surgical instrument, comprising: an outer tube formed from an electrically-insulative material; an inner tube formed from an electrically-insulative material; and an intermediate tube disposed between the outer and inner tubes, the intermediate tube formed from an electrically-conductive material and being electrically isolated within the outer and inner tubes, wherein distal ends of the outer and inner tubes extend beyond a distal end of the intermediate tube and are joined to one another to enclose the distal end of the intermediate tube therebetween. ### Claim 2 (depends on 1) The electrically-insulative shaft according to claim 1, wherein the distal ends of the outer and inner tubes are joined along a longitudinally-extending joint. ### Claim 3 (depends on 1) The electrically-insulative shaft according to claim 1, wherein the distal ends of the outer and inner tubes are joined along a transversely-extending joint. ### Claim 4 (depends on 1) The electrically-insulative shaft according to claim 1, further comprising an O-ring disposed between the outer and inner tubes and between the distal end of the intermediate tube and the joined distal ends of the outer and inner tubes. ### Claim 5 (depends on 1) The electrically-insulative shaft according to claim 1, wherein a radial space is defined between at least one of the intermediate tube and the inner tube or the intermediate tube and the outer tube. ### Claim 6 (depends on 1) The electrically-insulative shaft according to claim 1, wherein the intermediate tube substantially fully occupies an annular gap between the inner and outer tubes. ### Claim 7 (depends on 1) The electrically-insulative shaft according to claim 1, wherein the outer and inner tubes are formed from PTFE and wherein the intermediate tube is formed from stainless steel. ### Claim 8 (depends on 1) The electrically-insulative shaft according to claim 1, further comprising a body portion having a first diameter, a distal portion having a second diameter larger than the first diameter, and an annular step disposed between the body portion and the distal portion, the annular step having a varying diameter transitioning from the first diameter to the second diameter, the distal portion including the outer, intermediate, and inner tubes. ### Claim 9 A surgical instrument, comprising: a housing; at least one electrode operably coupled to the housing and configured to supply energy to tissue; and an electrically-insulative shaft extending at least partially between the housing and the at least one electrode, the electrically-insulative shaft including: an outer tube formed from an electrically-insulative material; an inner tube formed from an electrically-insulative material; and an intermediate tube disposed between the outer and inner tubes, the intermediate tube formed from an electrically-conductive material and being electrically isolated within the outer and inner tubes from the remainder of the surgical instrument, wherein distal ends of the outer and inner tubes extend beyond a distal end of the intermediate tube and are joined to one another to enclose the distal end of the intermediate tube therebetween. ### Claim 10 (depends on 9) The surgical instrument according to claim 9, wherein the at least one electrode includes a monopolar electrode. ### Claim 11 (depends on 9) The surgical instrument according to claim 9, wherein the at least one electrode includes a pair of bipolar electrodes. ### Claim 12 (depends on 9) The surgical instrument according to claim 9, wherein the distal ends of the outer and inner tubes are joined along a longitudinally-extending joint. ### Claim 13 (depends on 9) The surgical instrument according to claim 9, wherein the distal ends of the outer and inner tubes are joined along a transversely-extending joint. ### Claim 14 (depends on 9) The surgical instrument according to claim 9, further comprising an O-ring disposed between the outer and inner tubes and between the distal end of the intermediate tube and the joined distal ends of the outer and inner tubes. ### Claim 15 (depends on 9) The surgical instrument according to claim 9, wherein a radial space is defined between at least one of the intermediate tube and the inner tube or the intermediate tube and the outer tube. ### Claim 16 (depends on 9) The surgical instrument according to claim 9, wherein the intermediate tube substantially fully occupies an annular gap between the inner and outer tubes. ### Claim 17 (depends on 9) The surgical instrument according to claim 9, wherein the outer and inner tubes are formed from PTFE and wherein the intermediate tube is formed from stainless steel. ### Claim 18 (depends on 9) The surgical instrument according to claim 9, further comprising an elongated shaft assembly including a fixed outer tube extending distally from the housing, and the electrically-insulative shaft includes a body portion and a distal portion extending distally from the body portion, the body portion disposed within the fixed outer tube and the distal portion disposed distally beyond a distal end of the fixed outer tube, the distal portion including the outer, inner, and intermediate tubes. ### Claim 19 A method of manufacturing an electrically-insulative shaft for a surgical instrument, comprising: providing an electrically-insulative outer tube, an electrically-insulative inner tube, and an electrically-conductive intermediate tube; joining distal ends of the outer tube and the inner tube with one another to form a joint; inserting the intermediate tube into an annular gap defined between the outer and inner tubes such that the distal ends of the outer and inner tubes extend beyond a distal end of the intermediate tube and enclose the distal end of the intermediate tube therebetween; and enclosing a proximal end of the intermediate tube to electrically isolate the intermediate tube within the outer and inner tubes. ### Claim 20 (depends on 19) The method according to claim 19, wherein the distal ends of the outer tube and inner tube are joined with one another to form the joint prior to inserting the intermediate tube into the annular gap. ### Claim 21 (depends on 19) The method according to claim 19, wherein the distal ends of the outer tube and inner tube are joined with one another to form the joint after inserting the intermediate tube into the annular gap. ### Claim 22 (depends on 19) The method according to claim 19, wherein the distal ends of the outer tube and inner tube are joined with one another to form the joint such that the joint extends in one of a longitudinal direction or a transverse direction.