Systems and methods for expandable corpectomy spacer implantation

An insertion instrument adapted to surgically implant an implant assembly between two vertebral bodies, the insertion instrument comprising:

• proximal and distal ends and a longitudinal axis defined therebetween;
• and
• a split enclosure at the distal end, the split enclosure comprising a base portion and a housing cover hingedly connected relative to the base portion, the base portion and the housing cover defining a housing, the housing having a gearing mechanism disposed therein and accessible when the housing cover is open;
• wherein the gearing mechanism comprises a first bevel gear and a second bevel gear operatively connected to the first bevel gear, the first bevel gear mounted and longitudinally oriented within the housing to be selectively rotatable about the longitudinal axis of the insertion instrument, the second bevel gear mounted orthogonally to the longitudinal axis;
• wherein the insertion instrument comprises a retaining member secured relative to the first bevel gear to constrain the longitudinal orientation of the first bevel gear against non-longitudinally oriented bending moments to minimize risk of reduced operative engagement between the first bevel gear and the second bevel gear;
• wherein the insertion instrument comprises longitudinally extending inner and outer driving shafts with respective distal portions receivably insertable into the housing;
• wherein the insertion instrument comprises a retention ring extending inwardly from the housing cover, the ring being oriented to receive the driving shafts therethrough, the retaining ring having an inner surface opposing the outer driving shaft, whereby contact between the inner surface of the retention ring and the outer surface of the outer driving shaft prevents the cover from opening;
• wherein the gearing mechanism includes a proximal gear disposed within the housing and rotatable about the longitudinal axis, the distal end of the outer driving shaft being removably secured to the proximal gear via a first keyed connection, the first keyed connection adapted to transmit rotation of the outer driving shaft to rotation of the proximal gear, the keyed connection adapted to selectively disconnect the outer driving shaft from the proximal gear;
• wherein the distal end of the inner driving shaft is removably secured to the first bevel gear via a second, keyed connection, the second keyed connection adapted to transmit rotation of the inner driving shaft to rotation of the first bevel gear and to selectively disconnect the inner driving shaft from the first spur gear;
• wherein the insertion instrument comprises a sensor to sense previous use of the gearing mechanism, and wherein the insertion instrument comprises an indicator disposed at the proximal end to indicate the previous use;
• and
• wherein, in response to indication of the previous use, the first and second keyed connections are operable to disconnect the outer and inner driving shafts, respectively;
• wherein the housing has a proximal opening sized to permit withdrawal of the inner and outer driving shafts proximally therefrom to eliminate the contact between the retention ring and the outer driving shaft preventing the housing from being opened, whereupon the housing cover may be opened for cleaning of the gearing mechanism.

A removal tool for use with a corpectomy system, in which the corpectomy system includes an implant assembly for engagement between a first vertebral body and a second vertebral body, and in which the implant assembly has a core and at least one end cap selectively attachable to the core with resiliently flexible tabs, the removal tool comprising:

• a split clamp having first and second, C-shaped clamp portions with hingedly connected opposing ends, the C-shaped clamp portions having respective concave surfaces rotatable relative to each other to open and close the split clamp, the concave surfaces forming an inner surface extending circumferentially about a longitudinal axis of the split clamp and defining a clamp aperture through the split clamp when closed, the inner surface extending longitudinally between opposite, first and second transverse clamp sides;
• and
• a split ring having first and second split ring portions corresponding to the first and second clamp portions, the split ring portions defining an inner split ring aperture, the split ring aperture and the clamp aperture configured to operatively engage the core and the tabs of the end cap when the split clamp and split ring are closed around the implant assembly at a predetermined longitudinal location;
• wherein the split ring has two opposite ends, the first end connected to the split clamp to permit the split ring to be longitudinally displaceable relative to the split clamp, the second end having a threaded portion extending longitudinally between the first and second ends;
• wherein the removal tool includes a removal cap having threads thereon corresponding to the threaded portion at the second end of the split clamp and thereby advanceable on the threaded portion toward the first, transverse clamp side;
• and
• wherein the first end of the split ring and the split clamp are operatively interconnected to non-destructively disengage the tabs from the core in response to sufficient advancement of the removal cap relative to the split ring.