Instrument for the removal of a bone insert and corresponding method

Patent metadata

Field	Value
Publication number	US-10258484-B2
Application number	US-201414303433-A
Country	US
Kind code	B2
Filing date	Jun 12, 2014
Priority date	Jun 12, 2014
Publication date	Apr 16, 2019
Grant date	Apr 16, 2019

Abstract

The invention relates to an instrument and a corresponding surgical method for the removal of a bone insert, for example for a shoulder prosthesis. The instrument is of the type comprising:
a stem-like body ( 40 ) extending along a longitudinal axis (x-x) and provided with a proximal grip and a distal operating head ( 15 ) slidably associated with the stem-like body ( 40 ) for movement towards and away from each other; a cutting element ( 30 ) inside said operating head; and an end tip ( 16 ) protruding coaxially from said operating head. The following is also provided: a pushing mechanism ( 8 ), inserted inside said operating head and acting on said cutting element so as to displace it angularly from a rest position, where it is concealingly housed inside said end tip, to an operative position where it projects through a side opening in the end tip; said cutting element having an end extending substantially in a direction transverse to said longitudinal axis when in the operative position.

First claim

The invention claimed is:

1. Instrument for the removal of a bone insert; for example for a shoulder prosthesis, comprising:
a stem extending along a longitudinal axis and provided with a proximal grip;
a distal operating head slidably associated with the stem for movement towards and away from each other;
a cutting element inside said operating head;
an end tip, projecting coaxially from said operating head; said end tip having a base diameter which is smaller than a diameter of the operating head, said end tip projecting coaxially with the longitudinal axis from the distal portion of the operating head;
a pushing mechanism, inserted inside said operating head and acting on said cutting element;
a resilient element which constantly biases the operating head and the stem away from each other, said resilient element being arranged between the operating head and the stem;

wherein said cutting element is entirely curved in form of an arc of a circle and comprises:
a proximal portion, being a widest portion of the cutting element, slidable inside a matching shape guide formed in said operating head, and
a tapered blade;

wherein said pushing mechanism is configured to angularly displace the cutting element between:
a rest position, wherein the tapered blade is concealingly housed inside the end tip of the operating head, and
an operative position, wherein the tapered blade extends transversely with respect to the longitudinal axis, projecting in a cantilever manner through a side opening in the end tip;
and wherein said resilient element further biases said cutting element toward said rest position; and
wherein said pushing mechanism acts on a pin connected to said cutting element,

and wherein said pin is perpendicular to said proximal portion, being movable in a longitudinal direction and further slidable along a transverse direction inside a guide slot that is transverse to the longitudinal direction.

2. Instrument according to claim 1 , wherein the guide slot is formed at the distal end of the stem.

3. Instrument according to claim 2 , wherein the pin projects laterally and perpendicularly from said cutting element.

4. Instrument according to claim 2 , wherein said pushing mechanism comprises a distal end of said stem and wherein the pin is associated with said cutting element; said distal end acting on the pin when the stem is moved towards the operating head.

5. Instrument according to claim 2 , wherein the distal end of the stem is fork-shaped and engages with the pin via the guide slot and is configured for forcing the cutting element to slide matching shape guide against the action of the resilient element.

6. Instrument according to claim 1 , wherein the pin is integral with said proximal portion.

7. Instrument according to claim 6 , wherein the cutting element is formed integrally with the pin and projects from a matching seat formed in the operating head under a pushing force of a distal end of the stem.

8. Instrument according to claim 1 , wherein said operating head has an essentially cylindrical shape and wherein said matching shape guide comprises a circular-rim guide inside which said cutting element is movably guided.

9. Instrument according to claim 1 , wherein said end tip has a frustoconical form.

10. Instrument according to claim 1 , wherein said side opening in said end tip is an opening extending along the entire longitudinal extension of said end tip.

11. Instrument according to claim 10 , wherein the distal end of the stem has a circular cross-section and diameter smaller than an internal diameter of the operating head and that a spring-loaded means consists of a spring wound around the distal end of the stem.

12. Instrument according to claim 11 , wherein the spring extends resiliently inside a variable-extension, cylindrical, annular gap which is defined between an inner edge of the operating head and an edge formed by the smaller diameter of a distal end of the stem.

13. Instrument according to claim 1 , wherein said movement of the stem is performed against an action of resilient means.

14. Instrument according to claim 1 , wherein said cutting element is shaped as a sickle.

Assignees

• Limacorporate Spa

Inventors

• Pressacco Michele
• Ursella Simone
• Fiedler Christoph
• Paterson Paul D

Classifications

• A61B17/1617

  with mobile or detachable parts · CPC title

• A61F2/4612 Primary

  of shoulders · CPC title

• A61B17/1637

  Hollow drills or saws producing a curved cut, e.g. cylindrical (A61B10/025, A61B17/1695 take precedence) · CPC title

• A61B17/147

  with circularly moving saw blades, i.e. non-reciprocating saw blades · CPC title

• A61B17/1635

  for grafts, harvesting or transplants · CPC title