Method and apparatus for performing percutaneous bone surgery

Abstract

In making a bone implant to immobolize and support bone structure damaged by a fracture or other localized impairment, as for example the ball joint region of a femur (hip bone), after the surgeon penetrates the flesh by an incision of small diameter, a tubular guide is inserted through the incision, a drill is introduced through the guide and operated to drill a bore in the bone, a measuring sleeve is slipped over the exposed part of the shank of the drill to assist in measuring the depth of the bore, the measuring sleeve and drill are removed, a threaded pin of correct dimension is introduced through the guide, and screwed into the bore of the bone by a pin driver working through the guide. The latter is then withdrawn from the incision.

Description

BACKGROUND OF THE INVENTION

The use of metal pins or other implants to immobilize and support fractured bone sections while they heal, or for permanent use, particularly for fractures near the upper joint of the femur, commonly called hip fractures, is a well-known practice. Improvements in this art are disclosed and claimed in my copending application Ser. No. 342,442, filed Mar. 19, 1973. The practices known to me prior to the invention disclosed and claimed in that application required a relatively large incision with substantial disturbance of muscle and ligament structure and consequently a prolonged period of recuperation. My improvement comprehended a surgical pin longer than the section to remain in the bone and which could be inserted through a relatively small incision, the pin being formed with notches one of which could be selected for localized break off of pin by the use of a tubular tool of small diameter insertable through the incision over the section of the pin extending outwardly from the bone.

SUMMARY OF THE INVENTION

The present invention involves several significant departures from the subject matter of said copending application. In the present disclosure a tubular guide is employed for insertion through the incision. The guide is held in position at the angle desired for drilling the bore, and the drill is extended through the guide. The latter, in addition to guiding the drill, serves the function of protecting adjacent tissue from abrasion by the drill, and at a later stage insures correct placement of the pin for insertion in the bore. The guide also provides one element of a measuring means for the surgeon to determine the depth of the bore, in order to select from a series of finished pins one of the correct length.

Another element of the measuring means is a sleeve to be slipped over the rear end of the drill bit. The length of the guide and sleeve together equals the length of the drill bit. A stem is inserted in the tube until it touches the end of the drill bit. The stem used conveniently may be the pin driver (a specially designed type of screwdriver). The surgeon marks with his thumb the point on the stem where it emerges from the sleeve, and thus determines the depth of the bore. From this measurement he selects a pin of the proper length.

A number of features contributing to the efficiency of the apparatus and the success of the method will be discussed in the subsequent detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the drill bit.

FIG. 2 is a perspective view of the tubular guide.

FIG. 3 is a perspective view of the measurement sleeve.

FIG. 4 is a perspective view of an implant pin.

FIG. 5 is a perspective view of the implant driver.

FIG. 6 is a perspective view of a second form of implant pin.

FIG. 7 is an elevation, partly in section illustrating a drilling stage procedure in the method.

FIG. 8 is a view of the same character as FIG. 7 illustrating a bore measuring procedure.

FIG. 9 is a view illustrating the pin implant procedure.

FIG. 10 is an elevation partly in section, showing the pin implanted in the bone.

FIG. 11 is a view similar to FIG. 10 showing two pins implanted in the bone.

FIG. 12 is a view similar to FIG. 10 illustrating the second form of pin (FIG. 6) implanted in the bone.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A pin implant in the upper end of a femur 20 is chosen for illustration. Near the neck is shown a fracture 21. Surrounding the bone is body tissue 22 encased in skin 23. The surgeon's objective is to secure the parts of the bone on both sides of the fracture by a pin or pins later described. Usually there will be two or more pins, but for simplicity of illustration the implanting of a single pin will be described.

A small incision 26 is made from the skin to the bone, preferably at the general angle intended for the implant.

An elongated tubular guide 28 is introduced through the incision. The guide includes serrations 29 at the inner end, and a V shaped stiff wire-like pressure handle 30 is welded to the outer end of the guide. The surgeon usually works with a fluoroscope, in order to position the guide at the desired angle with the serrated end in contact with the bone. A light tap at the outer end of the guide will cause the serrations to bite into the bone, and by grasping the pressure handle with the fingers of one hand, steadying against the patient's skin surface, and exerting pressure directly toward the intersection of the guide and bone, a triangle fixation is accomplished so that the desired positioning may be maintained for subsequent steps.

The inside diameter of the tubular guide is such as to slidingly accommodate a bone drill bit 33. The drill preferably has two cutting diameters. The forward end section 35 has a smaller diameter than the rearwardly adjacent section 36. The shank section 38 of the drill bit is of sufficient length to extend well out from the rear end of the guide. A power chuck 40 is energized to rotate the drill, and a bore 45 is cut into the bone. This bore has a relatively small diameter section 46 and a relatively larger section 47 corresponding to the two cutting diameters of the drill bit.

Upon completion of the drilling the chuck is detached, and a measuring sleeve 50 is slipped over the shank end of the drill until it abuts against the outer end of the guide.

There must be a linear dimension relation between the guide, the drill and the measuring tube. The total length of the guide and sleeve should be equal to the length of the drill bit. As an example by way of illustration and not as a limitation, the drill bit may be 12 inches long, the tubular guide 7 inches, and the measuring sleeve 5 inches.

Thus the distance the drill has penetrated the bone, and consequently the depth of the bore, is determined by measuring the distance between the rear end of the drill shank and the rear end of the measuring sleeve. This can be achieved by inserting a stem or stick into the measuring sleeve and marking with the thumb the point where it emerges from the rear end of the sleeve.

Inasmuch as the procedure should be performed under sterile conditions, the most convenient item in the form of a stem is a pin driver 55 which must be present anyway. This pin driver comprises a shaft 60, with a handle 61, and a cruciform pin engagement end section 62. The cruciform section should extend up the shaft as generally illustrated for purposes which will be explained.

According to the measurement of the bore depth ascertained, the surgeon selects a pin 65 of the right length, so that when installed the rear end of the pin will protrude from the adjacent surface of the bone approximately the length of engagement slots hereafter described. The purpose is to enable removal of the pin after the bone has healed.

The pin includes a single cut penetrating end 66, a threaded section 67, a shank 68, and engagement slots 69. The slots receive the blades of the cruciform end 62 of the pin driver with a snug fit, and the slots are approximately as long as the cruciform end, so that when the pin driver is engaged with a pin the interlock will be positive and firm, with a minimum, if any, wobble or side play.

Threads on the pin preferably are the rolled type, with uniform outside diameter equal to or slightly greater than the diameter of the shank.

After selection of the pin, and with the drill bit removed but the tubular guide still held in place, the pin is inserted through the guide, the pin driver is brought into engagement with the pin and the latter is rotated into the bore of the bone. The advancement of the pin through the larger diameter bore section provides sufficient threaded anchorage so that further rotation of the pin will send the forward end section of the pin into the reduced diameter section of the bore. The result is a very tenacious securement between pin and bone.

The pin may be formed of titanium or other suitable material having the requisite properties of strength, and the several tool elements may be formed of stainless steel or other suitable material. The tubular guide should be thin walled, to minimize displacement of body tissue around the incision.

The use of the tubular guide performs the plural functions of directing the drill bit, protecting the body tissue from abrasion by the drill or the pin, contributing to measurement of the bore, insuring that the pin is sent straight into the bore in the bone, and aiding in the positive axial alignment of pin driver and pin.

The pin or pins may remain permanently in place, but in the usual case the fracture heals sufficiently that removal of the pin or pins is indicated, whereupon the incision may be reopened, the tubular guide properly positioned, and the pin driver applied in reverse to unscrew the pin.

In some situations it may be preferred to utilize a pin threaded at the rear end, as shown in FIG. 6, installed as in FIG. 12. For such purpose, a drill bit of a single cutting diameter ordinarily will be used. In all cases, the threads of the pin preferably are National Course type.

Although I have described my invention in what I have conceived to be the preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention.

Claims

I claim:

1. For use in pin implant in bone structure, the combination of: an elongated tubular guide adapted to be inserted through a small diameter skin incision and positioned with its inner end in direct contact with the bone surface and its outer end extending outwardly from the skin surface, an implant pin of a length generally corresponding to the depth of a bore made by a drill bit, the pin embodying a threaded section and having tool interlock means at a rearward end, said pin being slidably engaged within said guide with its rearward end directed outwardly, and a pin driver tool slidably engaged in said guide and comprising an elongated shaft embodying at a forward end means engaging the interlock means on the pin.

2. The combination of claim 1 in which the interlock means on the pin comprises a longitudinally slotted socket, and the means on the pin driver engaging the interlock means on the pin comprises a section slidable in the socket with blades extending radially into the slots of the socket whereby rotation of the shaft will impart rotation to the pin.

3. The combination of claim 1 in which the length of the pin is slightly greater than the depth of the bore made by the drill bit.

4. A combination as defined in claim 1 in which the inner end of the tubular guide is formed with serrations to slightly penetrate the bone and thus stabilize the guide in the location desired.

5. A combination as defined in claim 1 in which a pressure handle is fixed adjacent the outer end of the tubular guide adapted to be manually contacted as an aid in holding the guide in a position selected.

6. For use in pin implant in bone structure, the combination of: a drill bit of sufficient length to penetrate the bone defining a bore of a desired depth and to extend outwardly of the skin surface of the patient, and an elongated tubular guide shorter than the drill bit and in close slidable engagement thereon to guide the drill bit, the tubular guide being adapted to be inserted through an incision and positioned with its inner end in contact with the bone surface and its outer end extending outwardly from the patient's skin surface, the drill bit being removable from the bore, the incision and the tubular guide while the tubular guide remains in the incision so that a pin can be inserted into the tubular guide and the bore without removing the tubular guide, means referenced for association with the drill bit and the tubular guide for measuring the depth of a bore drilled in the bone comprising a sleeve slidably engaged on the rear exposed end of the drill bit and in abutment with the outer end of the guide, and a stem slidably engaged in the sleeve and in abutment with the rear end of the drill bit, the total length of guide and sleeve being equal to the length of the drill bit, and the linear measurement of the stem from its contact with the drill bit to the point of emergence from the sleeve representing the depth of the bore.

7. A combination as defined in claim 6 in which the inner end of the tubular guide is formed with serrations to slightly penetrate the bone and thus stabilize the guide in the location desired.

8. A combination as defined in claim 6 in which a pressure handle is fixed adjacent the outer end of the tubular guide adapted to be manually contacted as an aid in holding the guide in a position selected.

9. A combination as defined in claim 6 in which the drill bit embodies cutting sections of two diameters, the forward section being of less diameter than an adjacent following section.

10. In bone surgery involving the implanting of a pin in a bone structure comprising making of an incision of small diameter through flesh to the surface of the bone, the steps of: inserting a tubular guide through the incision into contact with the bone, manually holding the guide in the position desired, introducing a drill bit through the guide and operating the bit to drill a bore in the bone, while the bit remains in situ measuring the depth of the bore, withdrawing the bit, selecting a pin of a length generally equal to the depth of the bore, introducing the pin through the guide in alignment with the bore, and applying a tool through the guide to drive the pin into the bore.

11. A method as defined in claim 10 in which the depth of the bore is measured by placing a sleeve over the outwardly protruding end of the drill bit in end abutment with the guide, the total length of guide and sleeve being equal to the length of the drill bit, inserting a stem into the sleeve into abutment with the outer end of the drill, and determining by reference to the stem the distance from the outer end of the drill to the outer end of the sleeve, the distance being the bore depth.