Goniometer apparatus for brain surgery

July 26, 1966 w. hardy etal 3,262,452

GONIOMETER APPARATUS FOR BRAIN SURGERY

Filed April 17, 1963

Sheets-Sheet 1

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July 26, 1966

W. HARDY ETAL

3,262,452

GONIOMETER APPARATUS FOR BRAIN SURGERY

Filed April 17, 1963

Sheets-Sheet 3

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INVENTORS

BY

WM A QUiMLIVSW

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ffTTORA/f

July 26, 1966

W. HARDY ETAL

3,262,452

GONIOMETER APPARATUS FOR BRAIN SURGERY

Filed April 17, 1963

Sheets-Sheet 3

<img file="US3262452A_D0004.tif" />

United States Patent Office

3,262,452

Patented July 26, 1966

3,262,452 GONIOMETER APPARATUS FOR BRAIN SURGERY Wayne Hardy, 665 Grange Hall Road, and William F.

Quinlivan, 3812 Wales Drive, both of Dayton, Ohio Filed Apr. 17,1963, Ser. No. 273,611

Claims. (CI. 128—303)

This invention relates to surgical apparatus and, more specifically, to goniometric apparatus used in connection with brain surgery. Various neurological diseases characterized by tremors and rigidity are markedly improved when a small area of the brain is treated. This treatment consists of limited destruction by means of cutting or lesioning, electrocautery, ultrasound, freezing, or by introduction of chemicals. Although not limited' to such use, for the sake of simplicity and the simplification of terminology, the apparatus of this invention will be described in connection with lesioning. This lesioning process is accomplished by passage of a cannula to the specific area of the brain.

The lesioning process itself is relatively simple and well understood. Likewise, the actual lesioning itself requires very little time. The time consuming and, therefore, relatively expensive portion of the procedure has always been to locate the precise area on any given patient to be lesioned. This has been necessitated by the fact that the precise area within the brain cavity varies from patient to patient, and by the pronounced differences in the configuration of human skulls.

The surgery is performed through a small trephine or hole in the cranium; and the exact area to be lesioned is a definite area within the brain. The lesion area of the brain may be located by X-ray; however, since the brain is not a plane surface, the area must be located in both the anterio-posterior and the medio-lateral directions. It is obvious that, in order to insert a cannula through the trephine in the cranium and precisely reach the target area, the cannula must be precisely guided in both anterio-posterior and medio.-lateral directions. This has been done in the past by various apparatus; all of which required a progressive series of check Xrays because the devices were not accurate enough to be precisely adjusted from the initial X-rays. The old procedure was time consuming to the surgeon as well as causing unnecessary discomfort to the patient.

One object of the present invention is to provide an apparatus for precisely guiding the axis of a cannula to coincide with the axis through a trephine in the cranium and a precise area of the brain, in both anterioposterior and media-lateral directions from two X-ray films taken before surgery, one of which was taken in the anterio-posterior and the other in the medio-lateral position; the apparatus being set from the X-ray films.

Another object of the present invention is to reduce the number and the frequency of the X-ray requirements in the course of the surgery.

Still another object of the present invention is to provide an apparatus which, when removably joined to the patient’s cranium, may be set precisely to the determinations made on the X-ray films.

A still further object of the present invention is to provide a goniometer having the highest degree of accuracy, and which is nearly fool-proof in its use.

Additional objects, advantages and features of the invention reside in the construction, arrangement and combination of parts involved in the embodiment of the invention as will appear from the following description and accompanying drawings wherein:

FIG. 1 is a plan view, in reduced scale, of the goniometer.

FIG. 2 is a reduced scale side elevation, partially in section, taken along line 2—2 of FIG. 1 and rotated 90° to the left.

FIG. 3 is a plan section on line 3—3 of FIG. 2 showing an azimuth scale.

FIG. 4 is a plan section on line 4—4 of FIG. 2 with the upper swivel plate omitted and showing the method of linking the cannula guide to the adjusting micrometers.

FIG. 5 is a vertical section on line 5—5 of FIG. 3.

FIG. 6 is a front elevation of the base.

FIG. 7 is a rear elevation of the base showing a drainage passage.

FIG. 8 is an exploded perspective of a portion of the cannula guide and the elements linking it to the adjusting micrometers.

FIG. 9 is a perspective of the goniometer, and

FIG. 10 illustrates the method for determining the correct setting of the goniometer from an X-ray negative by using a transparent overlay. scale.

Referring to the drawings and, in particular, to FIG. 1, FIG. 2 and FIG. 9, the goniometer 11 has a base 12 which in use is joined to the patient’s cranium in a manner to be hereinafter described. The balance of the goniometer, referred to as indexing head 15, is removably and rotatably mounted on base 12. As will be better understood from a further reading of the specification, the terms “removable” and “removably” mounted or joined are to be differentiated from “disassembable,” in that there is a distinct function to be performed by the base when the indexing head is removed from the base; namely, to prevent body fluids flowing from the trephine in the patient’s skull and through the base from entering and encrusting on the indexing head, which if they did, would hinder the operation of the apparatus and would also form a site for infection. The indexing head 15 has for its more essential elements, a base collar or ring 14, a first quadrant means 18, a second quadrant means 16 at right angle to the first quadrant means, a cannula guide 20, a first threaded adjusting means or micrometer 24 and a second threaded adjusting means or micrometer 22.

FIG. 10 represents an X-ray negative of the patient on which a transparent scale 26 (shown fragmentarily) has been positioned for a purpose to be hereinafter described. The goniometer (except cannula guide 20 which is shown in section) has most of its elements shown in phantom lines to indicate that the major portions are made of aluminum, magnesium or other materials which do not completely shield the penetration of X-rays. The base 12 is attached to the patient’s skull, and the indexing head 15 is properly positioned and oriented on the base before the X-ray is taken. The goniometer has an azimuth scale, to be described hereinafter, to assure that the indexing head may be repeatedly oriented to the same position on the base. The base 12 has a flange 28, the lower face of which is contoured to the general shape of the human skull in the general area shown. The base is positioned to locate its vertical axis over the center of the trephine 30, which had been previously formed, where it is held in position by pin 32 and screw 34 which engage the skull.

Referring to FIG. 5, FIG. 6 and FIG. 7, the base 12, in addition to flange 28, has a circular boss 36 having a passage axially passing through the boss and flange and having a spherical seat 38 at the free end of the boss. One element of the azimuth scale previously mentioned is scribed on the upper part of the boss. The scribed element of the azimuth scale is best shown on FIG. 3 as scribed index line 40. As best shown on FIG. 5 and FIG. 7, the base also contains a passage 41 for the natural drainage of fluids from the tissues within the patient’s skull through trephine 30. As best shown on FIG. 3, the second element of the azimuth scale is shown on base ring 14 as scribed index 42, which is graduated through

3,262,452 ³ the full 360° of the circle. The azimuth scale provides a convenient means for repeatedly orienting the indexing head 15 to any position on the patient’s skull, where it is releasably held in place by lock screw 43. It is obvious that the azimuth scale may be reversed with the scribed index line 40 on the base ring 14 and the index 42 on the base 12.

Each of quadrant means 16 and 18 has an arcuate crown containing an elongated linear slot 16α and 18α as best shown on FIG. 9. The slots are of such width as to provide a free fit for retaining and guiding the upper end of the cannula guide 20 as shown. The lower open yoke end of each quadrant means is pivotally joined to base ring 14 by means of screws 44 as best shown on FIG. 5 and FIG. 9. Other pivoting means may be used; the important consideration being to provide a quadrant structure consisting of two means pivotally mounted at substantially 90° to each other and having superimposed crowns each arcuately movable in relation to the other. In order to provide ideal movement of components, the pivot axis of the first and second quadrant means should substantially be on a plane normal to the longitudinal passage through the cannula guide and passing through the geometrical center of the spherical seat 38 in base 12 when the indexing head 15 is joined to the base.

As best shown on FIG. 10, the cannula guide 20 is an elongated hollow tube having a ball end 46 at the lower end, and having a similar ball 48 at the mid section. The ball end 46 and ball 48 may be directly formed as shown; or, if desired, they may be made of ball elements and brazed in place. Ball end 46 is pivotally seated in seat 38 of base 12 as best shown on FIG. 5. As best shown on FIG. 2, joined to cannula guide 20 is a washer 50 providing a spring saddle for compression spring 52 which is disposed between washer 50 and quadrant means 18 to bias the cannula guide toward the base 12.

Referring in particular to FIG. 8 and FIG. 9, spindle 22α on micrometer 22 and spindle 24α on micrometer 24 each have a ball end 54 joined to the free end thereof by means of pin 56. Two triangular-shaped swivel plates 58, having holes in each corner area, are so placed on cannula guide 20 that one swivel plate is on each side of ball 48 on the cannula guide while the holes 60 in the other corner areas of the swivel plates engage the balls 54 on ball ends 54. All holes in the swivel plates may be straight holes; or, they may be contoured to the form of the respective balls. As best shown on FIG. 2 and FIG. 8, the upper and lower swivel plates 58 are resiliently held together to engage ball ends 54 by means of screw 62, compression spring 63 and nut 64.

Each micrometer may be axially adjusted on its respective quadrant means during instrument calibration by means of adjusting nuts 66 shown on FIG. 9. The calibration scale shown on each micrometer may be graduated to show the angular displacement of the cannula guide from its vertical zero position. During instrument calibration each micrometer is axially adjusted to read 0° on the calibration scale when the cannula guide is in its true vertical zero position. The particular scale used is a function of the distance between ball end 46 and ball 48 on the cannula guide, and the pitch of the micrometer thread. Micrometers calibrated to read linear measurements may be used, but such use requires a mental conversion of linear readings to angular equivalents on the cannula guide. The arrangement of elements is such that the axis through the cannula guide may be set to any simple or compound angle from the vertical zero position.

After the patient has been prepared and base 12 attached to the patient’s skull as indicated on FIG. 10, the indexing head is joined to the base and oriented in azimuth to place the axes of the micrometers into the anterio-posterior and medio-lateral planes on which the Xrays are to be taken; where it is held in place by lock screw 43. The azimuth reading is made of record in order that the indexing head may subsequently be re- turned to the initial position. The goniometer is set to have the axis of the cannula guide on the vertical zero axis 68 shown on FIG. 10. The patient, with goniometer attached, is then X-rayed; taking at least one picture in both the anterio-nosterior and medio-lateral positions. The indexing head is then removed, leaving the base on the patient’s skull.

After the X-ray films have been developed, the films are used to determine the correct compound angle of the cannula guide in order for the cannula to reach the lesion area 70 within the patient’s brain. FIG. 10 which represents an X-ray film in the anterio-posterior position shows the hypothetical lesion area 70 in that one plane of the film. The transparent scale 26 is superimposed over the film with the center of the scale over the ball end of the cannula guide as shown and the 0° line coinciding with the vertical zero axis 68 passing through the cannula guide when the X-ray was taken. The lesion area 70 is shown to be on the 5° line etched on the scale and indicates the correct required angular displacement of the cannula guide from its vertical zero position in the anterio-posterior plane in order to make the axis pass through the lesion area 70. When the cannula guide is displaced the required 5° by adjusting micrometer 22, the axis through the cannula guide will coincide with the 5° position on the scale and will be in proper alignment in the anterio-posterior plane. The procedure is repeated on the film taken in the medio-lateral direction; that adjustment being made with micrometer 24. It is obvious that the compound angle of the cannula guide is now properly positioned to place the axis through lesion area 70 in the patient’s brain.

The scale 26 is graduated in degrees on both sides of the 0° line as shown. For clarity, only each fifth degree line is shown full length on the drawing. Also on the scale, as shown, are a series of arcuate lines radiating from the scale center. These arcs may be graduated in inches as shown, or in the metric system. The arcuate lines are useful in estimating the distance of the lesion area 70 from such reference surface as the upper end of the cannula guide. It is obvious that the scale 26 may be superimposed on the film with the 0° line passing through area 70; in which case the necessary angular adjustment would be read on axis 68.

It is to be understood that the embodiment of the present invention as shown and described is to be regarded as illustrative only, and that the invention is susceptible to variations, modifications and changes within the scope of the appended claims.