The invention relates to surgical tools for aiding a surgeon installing orthopedic prostheses in patients.
A total hip replacement is a reconstructive surgical procedure performed by an orthopedic surgeon and the surgeon team. A total hip replacement involves the placement of an acetabular cup in a patient's acetabular socket, and the replacement of the patient's femoral neck with a prosthesis which terminates in a ball specifically designed to be positioned in the acetabular cup. Other surgical procedures may require the application of an acetabular cup or other device applied to a patient.
For example during such acetabular cup procedures, the patient's acetabular socket is reamed out by the surgeon so as to create an enlarged recess to receive the acetabular cup. After the acetabular socket has been reamed, the cup is inserted into the recess and adjusted as necessary to the proper angular orientation. Once deployed, the cup provides a new socket and lining for the patient's acetabulum.
Insertion and placement of the cup by the surgeon is effected either by hand or by use of a hand tool that grips the cup. Once the cup is properly positioned in the acetabulum, the cup can be fixed in the desired location by various means—bone screws, medically acceptable adhesives, or combinations thereof. In many instances, the fixation means include passing bone screws through the cup and into pre-drilled screw holes in the pelvic bone. The bone screws, which are optional, serve to hold the acetabular cup in the acetabulum until bone ingrowth provides permanent fixation.
In one acceptable medical method, the cup is properly positioned in the acetabulum by implantation. One conventional implantation method is, after obtaining proper alignment, to impact an acetabular cup into place. While impacting the acetabular cup, the surgeon listens for a change in pitch as the cup seats down. The surgeon then probes screw holes to determine if a gap between the cup and the bone is present. If a gap is present, the surgeon further impacts the cup into the acetabulum.
As illustrated in
The tool thread section 24 threadingly interconnects to a surgical implant device (a.k.a., medical attachment) 26, for example, and not limited to, an acetabular cup, through a threaded aperture 28 (
The rotate handle 30 is positioned in the spacing between the tool thread section 24 and the impactor thread section 20. At its proximal end, the rotate handle device 30 has a rotating threaded section 32 and at its distal end, an implant support 34. The rotating threaded section 32 has threads that mate with the impactor thread section 20. When the rotating threaded section 32 is rotated clockwise (illustrated by arrow 36 at
However, when the surgeon impacts the strike plate 12 there is a chance that the surgical implant 26 can disconnect from the tool holder 10. This could occur when the tool holder's 10 threaded section 24 or the implant's 26 corresponding threaded section 26 are damaged, possibly by the act of impaction. Accordingly, what is needed is a firm fixation of the surgical implant 26 during impaction that provides minimal damage to the implant's 26 threads 28. That desired product is achieved with the current invention.
The surgical tool handling device of the present invention has both non-moving and moving components during connection to an implant after the implant cup seats. However, during impaction, the entire surgical device is static or rigid. Having both moving and non-moving parts ensures a stable threaded connection between the surgical tool and the implantable cup.
The improved spindle-type surgical tool holder 100 has a strike plate 104, a body 106, a proximal fixed handle 108, a distal rotate handle 110, an insert handle with threads 112, an impactor head 114, a shaft 116, the shaft pin 102, a shaft ring 120, and a spring or any other conventional resilient member 122 (seen in
The strike plate 104 connects to the proximal end 124 of the body 106. As illustrated, the strike plate 104 is press-fitted, welded, or by any other conventional means is securely attached to the body 106; or alternatively, it is an integral part of the body. In the embodiment illustrated in
The proximal fixed handle 108 extends from the strikeplate 104 and is positioned over a fixed handle area 130 of the body 106 (
As illustrated in
Starting at the distal end 154, the body 106 has a cavity 156 of a diameter greater than the outer diameter of the shaft 116. That is so the shaft 116 can move in the cavity 156 along the body's and cavity's co-longitudinal axis 158 (
The slot area 148 contains a first axial opening 162 (
The distal rotating threaded area 150 is spaced a predetermined distance from the slot area's 148 distal end 166. That distance depends on the lengths of the distal rotate handle 110 and the insert handle with threads 112. The rotating thread area 150 has threads that mate with corresponding threads on the insert handle 112. The rotating thread area 150 has a length that allows the insert handle 112 to be rotated, through the distal rotate handle 110, to properly position the shaft ring 120, the shaft 116, and the surgical implant device 26 in order to decrease the chance of damaging or displacing the surgical implant 26 from the holder 100 during the surgical operation.
Extending from the rotating thread area 150 toward the body's distal end 154 is the insertion area 152. The insertion area 152 can be any desired length that assists and allows the surgeon to properly use the spindle-type surgical tool holder 100. Attached to the body's distal end 154 is the impactor head 114.
The impactor head 114 has a contacting surface 168 (
The interference fit cavity 180 has a second diameter, smaller than the first body cavity diameter, which receives the shaft 116, but not the body's distal end 154. The shaft 116 is capable of movement along the interference fit cavity. The interference fit cavity 180 also creates an obstacle that inhibits the threaded distal end 182 of the shaft 116 from entering the body cavity 176. The tip cavity 178 has a third diameter, greater than the second diameter, and equal to, smaller than, or greater than the first diameter. The third diameter is sufficient to allow the shaft's 116 threaded distal end 182 to move therein and extend from the head's distal end 174.
The contacting surface 168 is at the head's distal end 174. The contacting surface 168 is designed to contact the interior surface of the surgical implant 26 (similar to how the prior art's implant support 34 operates). In that respect, the contacting surface 168 is designed to provide an additional stabilization surface to the surgical implant device 26 during the surgical procedure and to inhibit the implant 26 from disconnecting from the spindle-type surgical tool holder 100.
As shown in
Extending in the proximal direction of the shaft 116 from the threaded distal end 182 is the elongated intermediate section 184. The elongated section can be a single diameter or multiple diameters (as illustrated in
Adjacent to the shaft's 116 proximal end is the pin section 186. The pin section 186 has a shaft aperture 194 that extends from one side to the opposing side of the shaft as illustrated in
The shaft aperture 194 has a diameter that receives and, possibly, secures the shaft pin 102 in place. The aperture and pin relationship can be a loose fit, a press-fit, a conventional rib and indent system, a conventional spring-loaded ball and indent system, or any functionally equivalent system that fixedly attaches the pin in the aperture or securely attaches, and also allows the release of, the pin in the aperture, or alternatively allows the pin 102 to move freely within the aperture 194. The aperture and pin relationship depends on how the pin 102 is used in association with other components of the present invention. For example, if there is no shaft ring 120, the pin and aperture have to be permanently attached or securely attached. Likewise, if there is a shaft ring 120, then the pin and aperture can be any of the three possible attachment embodiments especially if the shaft ring and the pin are securely attached to each other.
Prior to inserting the pin 102 in the aperture 194 and through the shaft's first and second axial openings 162 and 164, the shaft ring 120 is properly positioned on the shaft's exterior surface 196. As previously stated, the spring 122 is positioned in the fixed handle's 108 spring cavity 138 with its proximal end 144 contacting the spring abutment 140. Likewise, the proximal end 198 of the shaft ring 120, preferably contacts the fixed handle's ring stopper distal end 136. In addition, the shaft ring 120 has one or, preferably, two pin apertures 200, 202 that are diametrically opposed to each other. Each pin aperture extends from the shaft ring's outer surface 204 to its respective inner surface 206 and has a diameter that receives and secures the pin 102 in place. The pin apertures 200, 202 and shaft pin 102 relationship can be a press-fit, a rib and indent system, a spring-loaded ball and indent system, or any functionally equivalent system that either permanently attaches the shaft pin in the apertures 200, 202 or securely attaches, and also allows the release of, the pin 102 in the apertures. As expected, the pin apertures 200, 202, the shaft aperture 194 and the shaft's 116 first and second axial openings 162 and 164 must be aligned to receive the shaft pin 102.
Prior to or after the shaft pin 102 is properly positioned and secured in the apertures 200, 202, the shaft aperture 194 and the first and second axial shaft openings 162 and 164, and the rotate handle 110 are positioned over a portion of the exterior surface of the insert handle with threads 112. This assembly is then positioned over the rotating handle 110/ring 120 area's 146 exterior surface 196. The distal rotating handle 110 has a proximal end 208 that contacts the distal end 210 of the shaft ring 120, and a distal end 212. The distal end 212 has a threaded insert handle stopper 214, an insert handle cavity 216 (
The insert handle 112 has a distal threaded area 220 and a proximal rotating area 222. The threaded area 220 has an outer diameter 224 (
In use, when a surgical implant device 26 is threaded onto the shaft's threaded area 190, the surgeon merely rotates the assembly comprising the distal rotate handle 110 and the insert handle with threads 112 in one direction, normally clockwise (see arrow 15 in
Then, in order to position an implant 26 in an acetabulum, an axial force is imparted to the strike plate 104 connected to the body 106. The body 106 is housed inside the proximal fixed handle 108 is, in turn, rigidly connected to the shaft 116 having its proximal end 116A seated in na distal recess 106A of the body 106. The opposite, distal end of the shaft is threaded into the implant 26. That way, the entire assembly is static or rigid with the implant attached held firmly against impactor head 114. This provides a good tactile feel to the surgeon as the force imparted to the strike plate 104 translates through the tool holder 100 to effect implantation of the cup 26.
As illustrated at
Although several embodiments of the invention have been described in detail for purposes of illustration, various modifications of each may be made without departing from the spirit and scope of the invention. For example, there can be just one opening or a plurality of openings for the slot area. The shaft pin may only extend from one opening or two openings. In addition, there may be numerous shaft pins extending from one opening or two openings in the slot area. The resilient member can be a spring of any conventional resilient object made of metal, plastic, or a gelatinous elastomeric material made from an A-B-A triblock copolymer. Examples of A-B-A triblock copolymers are SEP, SEB, SEBS, SEEPS (“S” is styrene monomer(s), “E” is ethylene monomer(s), “B” is butylene monomer(s), and “P” is propylene monomer(s)) and variations thereof made by the Kuraray Corporation. The directions of clockwise and counterclockwise can be transposed depending on the thread types. Depending on the shape of the shaft pin, the shaft ring is optional. Accordingly, the invention is not limited, except by the appended claims.