EP0814742A1

EP0814742A1 - Surgical headrest

Info

Publication number: EP0814742A1
Application number: EP96901415A
Authority: EP
Inventors: Olivier Delattre
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-11-09
Filing date: 1996-01-18
Publication date: 1998-01-07
Also published as: FR2726465B1; WO1997025956A1; JPH11502146A; FR2726465A1

Abstract

A device for supporting the head of a patient lying face down on an operating table so that proper head stabilisation is achieved without compressing the patient's eyeball. The device is particularly suitable for posterior approach vertebral surgery.

Description

SURGICAL HEAD

The present invention relates to a surgical headrest, a device used to maintain the head of patients installed in the prone position during surgical interventions relating to the spine, by posterior approach.

The surgical headboards currently used include a headrest in the shape of a "horseshoe", padded on its upper part. The eyeballs are theoretically protected from possible compressions because they are located inside the support zones, the head being stabilized in the correct position by several bands of elastoplast.

These headrests have two drawbacks.

Poor stabilization of the head on the headrest: the very shape of the headrest, which fits into a single horizontal plane, means that it can only stabilize the head in one plane. It only prevents one movement: the fall of the head downwards. It is in fact only a supporting role, the stabilization function being only performed precariously by elastoplast bands.

Poor protection of the eyeballs: in fact, these headrests include periorbital support zones which become dangerous for two reasons:

- the non-adjustable nature of most of these headrests means that they are not always adapted to different cranial morphologies, the risk being contact with one of the eyeballs on a branch of the headrest. Risk favored by a large opening of the eyes, poor pronounced malar protrusions, a tendency to exophthalmos;

- the poor stabilization of the head on the headrest during the intervention, allows micromovements of lateral translation, anteroposterior, rotation, which can bring during the intervention one of the eyeballs in contact with one of the branches of the headrest, while both eyes were free, within the support zones, at the start of the intervention.

This risk of intraoperative compression of the eyeball is significant. It is essential to take this into account, when you know that it only takes a compression of the eyeball for 30 minutes to cause permanent monocular blindness. These serious ocular complications (permanent monocular blindness by prolonged intraoperative compression of an eyeball on one of the branches of the headrest) are not exceptional. The present invention aims to overcome these two drawbacks, the aim being to cancel the risk of intraoperative compression of the eyeball while perfectly stabilizing the head.

To this end, the headrest which it concerns has no bearing surface in the periorbital area. The invention is characterized by a very precise distribution of the bearing surfaces (in triangulation) in three anatomical regions:. chin area,

. upper frontal area (away from the upper edge of the orbit (more than 15 mm)),

. parietal zone (right and left).

The surgical headrest intended for the manten of the head of patients installed in prone position, includes:

. a main support consisting of four tubes assembled two by two forming an L included in a vertical plane parallel to the plane, the two L being assembled substantially parallel to each other by their respective angles on a support means,. a support for a chin rest coming to slide (according to OX) on the rear part formed by the two horizontal tubes,. a support of a parietal support connecting the upper part of the two vertical tubes,. a support of a frontal support, fixed on the middle part of the support means of the main support, the assembly realizing an arrangement in triangulation of the support zones, with a chin support, a frontal support and a parietal support, whose forces of support are concentrated in the center of the skull, the main support of the headrest resting on a vertical support means by means of a system allowing an orientation of the whole of the headrest in translation along the OX axis and in rotation along the OZ axis. Advantageously, the support means of the main support, and / or the support of a mentioned support and / or the vertical support means are tubes. Preferably, the parietal support support is a tube sliding on the upper part of the two vertical forming a slide, said tube forming a sliding support of a parietal support. The definition of "tube" should be understood in its broadest sense, regardless of its section, circular or polygonal, hollow or solid. The accompanying drawings illustrate the invention: FIG. 1 represents a perspective view of the headrest assembly,

FIG. 2 is a functional diagram of the entire faceplate where the adjustments and blockages are represented,

- Figure 3 is a diagram showing the static balance of the stabilized head on the headrest.

The entire headrest has a vertical plane of symmetry OX, OY merged with that of the patient's head.

It includes a main support made up of five tubes forming two by two 5a and 5b, 5c and 5d, an L included in a vertical plane parallel to the plane O, X, Y. The two L are assembled together by their angles on the fifth 5g tube.

On the rear part of the slide formed by the two horizontal tubes 5a and 5b, there slides, according to OX, a sixth tube 5e, sliding support of a chin rest 21 itself sliding transversely, according to OZ, on its support 5e, and rotatable around it (in the plane O, X, Y).

On the upper part of the vertical slide formed by the two vertical tubes 5c and 5d, a seventh tube 5f slides to the middle part of which is fixed an intermediate support 12 crossed by a horizontal cylindrical rod sliding along OX connected at its posterior end to a yoke 14 on which is articulated a prismatic nut 16 which receives a maneuvering screw at the lower end of which is pivoted a double parietal support, composed of two lateral pads 18a and 18b articulated on a lifting beam 17. On the middle part of the horizontal tube 5g of the main support is fixed the support 8 of a double front support composed of two pads 6a, 6b in the shape of a spherical cap with concavity turned towards the skull, pads articulated on a lifting beam 9, ball joint on the support 8, allowing orientation in all directions over a maximum angular amplitude of approximately 20 °.

The assembly achieves a triangulation arrangement of the support zones with three adjustable supports:. chin support,. a double frontal support (right and left),. double wall support (right and left).

The main support of the headrest rests on a vertical support rod 1 by means of a system allowing an orientation of the entire headrest in translation along the OX axis and in rotation about an OZ axis.

The whole of the headrest (main support and its supports) is connected to the horizontal support slide 3 according to OX via the support tube 5g which crosses the slide at its upper part in two ears allowing a blocking by two pinches arranged on the side and other of the support 8. This device allows rotation of the headrest about an axis OZ of the support 5g (FIG. 2). This allows flexion / extension maneuvers of the cervical spine (necessarily associated with a certain traction insofar as the axis of rotation passes through the frontal region, therefore in front of the cervical spine.

The support slide 3 rests on a horizontal prismatic slide 2 according to OX, secured to a vertical support rod 1 which connects the assembly to the operating table. This device allows by a screw-nut system actuated by the button 4 a fine adjustment in translation of the whole of the headrest according to OX.

According to a particular embodiment not illustrated, the previous axis OZ of rotation can be moved backwards and upwards at the level of the average cervical vertebrae (third or fourth). In this design, the main support of the headrest would have two toothed sectors of large diameter and 90 ° angle, located on either side of the plane of symmetry of the headrest and centered on the planned pivot axis. Two pinions, integral with an axis guided in rotation by the slide 3 driven by an operating handwheel, mesh with each of the toothed sectors, causing their simultaneous rotation.

The axis of rotation of the sectors not being materialized, the contact of the teeth of the sectors with those of the pinions will be maintained by means of two rollers located in opposition and rolling inside the toothed sectors.

In this case the movements transmitted to the cervical spine would be flexion / extension movements without associated traction.

In this particular embodiment, the slide is connected to the main support by the gears.

The head is first placed in position on the mental support and on the front support. The chin support 21 of parallelepiped shape hollowed out on its upper face by a cavity conforming to the shape of the chin, closed towards the rear and opening towards the front, is supported by the transverse tube 5e crossing following OZ at its lower part. The tube 5e is connected at its ends to the horizontal tubes 5a and 5b of the main support by two sliding ends split horizontally on their external face. This system allows the displacement of the chin support in horizontal translation according to OX. Once correctly positioned, the blocking is obtained by adhesion thanks to two pinches carried out by the two buttons 19. The chin support is also orientable transversely according to OZ on its support tube 5e and in rotation around it, the blocking by adhesion being obtained by pinching with the button 22. The front support is composed of at least one shoe, advantageously one or two shoes 6a and 6b, in the form of a spherical cap with a large radius whose concavity is oriented towards the skull, articulated by an appropriate means fixed to the support means 5g of the main support, allowing the front support to be oriented in all directions. According to a preferred embodiment, the front support is articulated by its convex face on a support with double yoke 9 forming a spreader. This lifter is ball joint on a parallelepipedic support 8 fixed to the transverse tube 5g of the main support. This system allows the front support to be oriented in all directions over a maximum angular amplitude of around 20 °. This spreader system allows self-adaptation to different cranial morphologies. The blocking of the entire front support (pads 6a and 6b, lifter) is obtained by adhesion thanks to the tightening by a button 7 located on the rear face of the support 8.

These different adjustment possibilities allow, whatever the shape of the faces, to leave the periorbital area free of any support while maintaining the frontal supports in the upper frontal region at a distance from the upper periorbital area.

After placing the head on the front support and on the chin support, a blocking device ensuring the stability of the head on the headrest is produced by the placement of the parietal support. It maintains contact with the previous supports.

According to a first embodiment, the parietal support comprises two pads in the form of a spherical cap with a large radius, with a concavity oriented towards the skull, articulated by appropriate means, allowing adjustment of position according to OX of the assembly, this assembly being fixed on the middle part of the parietal support support 5f allowing the displacement of the assembly of the parietal support in vertical translation according to OY. It includes one or more skids in the shape of a spherical cap with a large radius, with a concavity oriented towards the skull, articulated on another lifter 17. This lifter is ball jointed by its upper face on an operating screw actuated by the button 15. A nut 16 prismatic receives this screw, it is articulated on a yoke 14 connected to a parallel-pipedic intermediate support 12 by a horizontal cylindrical rod sliding along OX. A position adjustment according to OX of the skid-lifter-blocking system assembly is possible by sliding the yoke rod 14 in the support 12. The blocking in good position on the support 12 is obtained by tangent buffers maneuvered by a button 13.

This assembly is fixed to the middle part of the horizontal tube 5f along OY by the intermediate support 12 which is crossed by it. The tube 5f is connected at its ends to the vertical tubes 5c and 5d of the main support by two sliding end pieces split vertically on their external face. This system allows the displacement of the whole of the parietal support in vertical translation according to OY. Once correctly positioned, the blocking is obtained by adhesion thanks to two pinches carried out by the two buttons 1 1.

After having correctly positioned and blocked the parietal support by these two adjustments (according to OX and according to OY), the head is stabilized by actuation of the screw-nut system 16, produced by tightening the button 15. The pressing force produced by this device can be limited to a maximum value by a friction torque limiter incorporated in the button 15. It would limit the bearing force on the skull which would no longer be dependent on the manipulator.

According to a second embodiment, the two vertical tubes 5c and 5d, connected by the support of a parietal support 5f, constitute a single U-shaped tube, the ends of which are connected to the horizontal tubes by an appropriate means allowing the adjustment and the blocking of the parietal support in translation along the OY axis, and in rotation along the OZ axis, the parietal support being fixed directly on the middle part of the base of the U. The parietal support is adjusted by first rotating the entire U along the axis OZ, to obtain the desired angle, then performing with translation so as to bring the parietal support into contact with the skull in the desired position. If necessary, the blocking of the wall support once adjusted, can be carried out by a single command. The wall support can be 97/25956 PC17FR96 / 00086

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consisting of one or more skids in the form of a large radius spherical cap.

The stability of the head after its installation on the headrest, requires the static balance of the applied forces (support forces (chin support and frontal support), blocking forces (parietal support)).

Figure 3 represents the forces applied by the various supports:

. F21: resulting from the forces exerted by the mental support on the head, it is located in the plane of symmetry. . F6 and F6 ': forces exerted respectively by the two pads 6a and 6b of the frontal support, on the head. Their resultant R6 is also in the plane of symmetry, its direction intersects that of F21 at point 1.. FI 8 and FI 8 ': forces exerted respectively by the two manten pads (18a and 18b) of the parietal support on the head. Their resulting RI 8 is also in the plane of symmetry.

In total, the set of forces applied to the head comes down to three forces (F21, R6 and RI 8). The condition of equilibrium of the head is that these three forces are concurrent at the same point. This condition is achieved by adjusting the position of the parietal support, in particular along OX, so that the resulting RI 8 converges towards point 1, close to the center of the skull. This adjustment also allows a harmonious distribution of the locking force on the two supports, chin and frontal. The materials used are:

- for the main structure: hollow epoxy carbon fiber tubes assembled by bonding on prismatic nylon blocks with an Araldite epoxy adhesive with shear strength of 10 to 15 N / mm2,

- the other elements are made of nylon,

- the surfaces of the supports in contact with the head are covered with foam.

These materials are relatively radio-transparent and resistant to the various products used in the operating room.

Certain elements, in particular for the particular embodiment comprising a gear system could be made of stainless steel but located outside the useful radiography area, leaving the cervical and occipital area perfectly free. The device according to the invention is a surgical headrest particularly intended for the stabilization of the head and the protection of eyeballs of patients installed in prone position during vertebral surgery by posterior approach. It could also be used during other surgical procedures requiring the prone position.

Claims

1 / Surgical headrest intended for the manten of the head of patients installed in the prone position, characterized in that it comprises:. a main support consisting of four tubes assembled in pairs (5a and 5b, 5c and 5d) forming an L included in a vertical plane parallel to the plane (O, X, Y), the two L being assembled substantially parallel to each other by their respective angles on a support means (5g),. a support for a chin rest (5e) sliding (according to OX) on the rear part formed by the two horizontal tubes (5a, 5b),

. a support of a parietal support (5f) connecting the upper part of the two vertical tubes (5c, 5d),. a support (8) of a front support, fixed on the middle part of the support means (5g) of the main support, the assembly making a triangular arrangement of the support areas, with a chin support, a front support and a parietal support, the support forces of which are concentrated in the center of the skull, the main support of the headrest resting on a vertical support means (1) which can be secured to the operating table, by means of a system allowing orientation of the entire headrest in translation along the OX axis and in rotation along the OZ axis.

2 / surgical headrest according to claim 1, characterized in that the support means (5g) of the main support, and / or the support of a mentioned support (5c) and / or the vertical support means (1) are tubes. 3 / surgical headrest according to one of claims 1 or 2, characterized in that the parietal support support (5f) is a tube sliding on the upper part of the two verticals (5c and 5d) forming a slide, said tube forming a sliding support with a wall support.

4 / Surgical headrest according to one of claims 1 to 3, characterized in that the chin support (21) is of parallélé¬ piped shape, hollowed on its upper face with a cavity matching the shape of the chin, supported by the transverse tube (5th) passing through it along OZ at its lower part, the chin rest being adjustable in translation and in rotation along the axis OZ. 5 / surgical headrest according to one of claims 1 to 4, characterized in that the front support is composed of at least one pad (6a and 6b), in the form of a spherical cap with a large radius whose concavity is oriented towards the skull, articulated by an appropriate means fixed to the support means (5g) of the main support, allowing the front support to be oriented in all directions.

6 / Surgical headrest according to one of claims 1 to 5, characterized in that the parietal support comprises two pads in the form of a spherical cap with a large radius, with concavity oriented towards the skull, articulated by appropriate means, allowing adjustment of position according to OX of the assembly, this assembly being fixed on the middle part of the parietal support support (5f) allowing the displacement of the assembly of the parietal support in vertical translation according to OY.

7 / surgical headrest according to one of claims 1 to 5, characterized in that the two vertical tubes (5c and 5d), connected by the support of a parietal support (5f), constitute a single U-shaped tube of which the ends are connected to the horizontal tubes by an appropriate means allowing the adjustment and the blocking of the parietal support in translation along the OY axis, and in rotation along the OZ axis, the parietal support being fixed directly on the middle part from the base of the U.

8 / surgical headrest according to one of claims 1 to 7, characterized in that the rotational orientation of the entire headrest is around an axis OZ located rearward and upward at the medium cervical vertebrae (third or fourth).

9 / Surgical headrest according to one of claims 1 to 8, characterized in that the materials which constitute it are essentially radio-transparent materials and resistant to the various products used in the operating room.