DESCRIPTION OF THE PRIOR ART Conventional operating tables comprise an operating table top and a pedestal adjustment mechanism which extend substantially the entire length of the operating table top. Such operating tables, although useful for performing general surgical procedures. do not provide the surgeon with adequate leg room for performing specialized surgical procedures, such as phacoemulsification cataract surgery, where the surgeon must be seated in order to access foot controls while operating.

Specialty operating tables have been developed for performing seated surgical procedures, such as eye surgery. However, such operating tables are very expensive and therefore would only be suitable for hospitals performing high volume eye surgery.

The Galbraith table top was developed as a lower cost alternative to specialty operating tables. The Galbraith table top comprises a short flat plate with an adjustable steel wrist rest, for enhancing wrist stability while operating. The table top is placed under the operating table mattress, between the mattress and the base of a conventional operating table. However, the Galbraith table top only extends a short distance along the length of the operating table base and is held in place only by the combined weight of the mattress and the patient. As a result, the Galbraith table top is inadequate for performing seated surgical procedures because the table top can only be extended a short distance beyond the end of the operating table base. Furthermore, as the Galbraith table top typically is not secured to the operating table base, the table top is prone to sliding out from under the mattress should the operating table need to be tilted. As a result, the

Galbraith table top cannot be used in situations where the patient must be tilted - e. g., to the Trendelenburg position in response to a drop in the patient's blood pressure.

Accordingly, there remains a need for an inexpensive table top which can be safely used with conventional operating tables for performing seated surgical techniques.

SUMMARY OF THE INVENTION According to the invention, there is provided an inexpensive lightweight table ~ top which can be safely secured to conventional operating tables and which provides the surgeon with sufficient leg room for performing seated surgical procedures.

The operating table top, according to the invention, comprises a substantially planar sheet having a pair of opposed upper and lower surfaces and including reinforcement means for increasing rigidity of the sheet.

The operating table top preferably extends substantially the full length of the operating table and includes a body portion and a head portion extending from the body portion. The table top is held in place by the combined weight of the mattress and the patient, and can be secured to the operating table by securing means.

In one embodiment, the reinforcement means can be in the form of ribs attached to one or both of the upper and lower surfaces of the planar sheet. In another embodiment, the reinforcement means may be integral in the material used to construct the planar sheet. For example, the planar sheet may be made of metal mesh which has sufficient rigidity to be useful in the present operating table top. A typical such sheet could be constructed of aluminum, stainless steel and the like. The optimal thickness of the sheet can be readily determined once the material to be used is selected. For example, if the sheet is to be constructed of aluminum, a 3 or 5mm thick sheet will be sufficient for most purposes.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals indicate like elements, and in which :

Figure I is a top plan view of the operating table top, according to the invention ; Figure 2 is a side view of the operating table top ; Figure 3 is a bottom plan view of the operating table top ; Figure 4 is a schematic view of the operating table top secured to a conventional operating table ; and Figure 5 is a bottom plan view of one variation of the operating table top shown in Figure 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning to Figure 1, an operating table top, denoted generally as 10, is shown comprising a thin substantially planar rectangular or elongate sheet 12 having a pair of opposed parallel surfaces 14,16, a pair of parallel opposite ends 18,20, a body portion 22, a head portion 24 and a neck portion 26 extending between the body portion 22 and the head portion 24. It will be appreciated that the rectangular shape of the sheet 12 allows a conventional operating room mattress to be placed on the upper surface 14 of the sheet 12. However, it should be understood at the outset that the sheet 12 need not have a rectangular shape but may have any other shape suitable for having a mattress placed thereon.

The body portion 22 includes a pair of parallel opposite sides 28,30 and extends over a major portion of the length of the sheet 12 between the end 18 and the neck portion 26. Preferably, the length of the body portion 22 is at least equal to the length of a conventional operating room table.

The head portion 24 also includes a pair of parallel opposite sides 32,34 and extends over a minor portion of the length of the sheet 12 between the end 20 and the neck portion 26. The neck portion 26 includes a pair of inturned sides 36,38 extending the length of the neck portion 26, such that the side 36 extends inwards from the side 28 to the side 32, and the side 38 extends inwards from the side 30 to the side 34. As a result, the width of the sheet 12 is greater across the body portion 22 than across the head portion 24. However, it should be understood that the width of the head portion 24 need

not be less than the width of the body portion 22. In one variation (not shown), the width of the body portion 22 is equal to the width of the head portion 24.

Turning to Figure 2, it is apparent that the neck portion 26 inclines upwards from the body portion 22 towards the head portion 24 such that the upper surface 14b of the head portion 24 is elevated slightly above but also parallel to the upper surface 14a of the body portion 22. As will become apparent, the elevated head portion 24 reduces neck strain on the patient lying on the table top 10. However, it should be understood that the head portion 24 need not be so elevated but instead may simply be coplanar with the body portion 22.

Turning again to Figure 1, the body portion 22 is shown including a plurality of apertures 40 (shown individually as 40a, 40b, 40c, 40d, 40e, 40f, 40g, 40h) positioned adjacent the sides 28,30 of the body portion 22 and extending between the upper surface 14 and the lower surface 16. As will be explained, the apertures 40 are adapted to receive retaining straps, each retaining strap being secured at one end thereof to the sheet 12 for securing the table top 10 to the top of a conventional operating room table. Of course, those of skill in the art will immediately recognize the table top 10 may be secured to the top of a conventional operating room table by any other suitable means such as hooks, loops, U-bolts and the like.

To increase the rigidity and stability of the table top 10, the sheet 12 includes reinforcing ribbing integrally molded with the upper surface 14a of the body portion 22.

As shown in Figure 1, the reinforcing ribbing comprises a plurality of parallel ribs 42 (shown individually as 42a, 42b, 42c) extending upwards from the upper surface 14a of the body portion 22. The ribs 42 are equidistantly spaced across the width of the body portion 22 and extend over substantially the entire length of the body portion 22. As will be appreciated, the number and spacing of ribs 42 may vary according to the level of rigidity desired. Furthermore, each rib 42 need not be continuous, as shown in Figure 1, but instead may comprise a plurality of smaller ribs.

As discussed hereinabove, ribs 42 may be eliminated if sheet 12 is made of a sufficiently rigid material such as 3 or 5mm thick aluminum, preferably in mesh form to provide an optimal balance between rigidity and weight.

Turning now to Figure 3, the sheet 12 is shown also including reinforcing ribbing integrally molded with the lower surface 16b of the head portion 24 for increasing the rigidity and stability of the table top in the head portion 24. As shown in Figure 3, the reinforcing ribbing comprises ribs 44a, 44b, extending downwards from the lower surface 16b of the head portion 24. The ribs 44a, 44b each extend from a respective opposite corner 46,48 of the head portion 24 and intersect at a point on the lower surface 16b adjacent the neck portion 26.

For added stability, the sheet 12 includes reinforcing ribs 50a, 50b, 50c, 50d, extending over the circumference of the sheet 12. The reinforcing ribs 50a, 50b slope downwardly along the sides of the sheet 12 such that the ribs 50a, 50b extend above the upper surface 14 of the sheet 12 adjacent the end 18, and extend below the lower surface 16 of the sheet 12 adjacent the end 20. Similarly, the rib 50c adjacent the end 18 extends above the upper surface 14a and intersects with the ribs 50a, 50b at the end 18, while rib 50d adjacent the end 20 extends below the lower surface 16b and intersects with the ribs 50a, 50b at the end 20.

Turning to Figure 4, the table top 10 is shown secured to a conventional operating table 110 with suitable retaining straps 112. As will be appreciated, the retaining straps 112 only serve to anchor the table top 10 to the operating table 110, and therefore may be replaced with other securing means known to those skilled in the art.

The head portion 24 extends laterally outwards beyond the end of the operating table 110 to provide the surgeon with adequate leg room while seated next to the head portion 24.

A mattress 114 is positioned on top of the table top 10 and is secured thereto by the weight of the patient (not shown). The mattress 114 sinks down over top of the ribs 42 until the lower surface of the mattress 114 contacts the upper surface 14a of the body portion 22. As a result, the vertical space occupied by the table top 10 and the mattress 114 is minimized.

In a preferred implementation of the invention, the sheet 12 adopts the shape shown in Figure 1, and is fabricated from aluminum sheeting which is 3mm thick.

Alternatively, the sheet 12 is selected from the group of materials comprising stainless steel, Kevlar, fiber-reinforced resin, plastic (e. g., polycarbonate) and the like. The

sheet 12 is 208cm long! 50cm wide at the end 18. and 45cm wide at the end 20. The head portion 24 is 28cm long from the neck portion 26 to the end 20, while the length of the body portion 22 and the neck portion 26 combined is 180cm. The neck portion 26 inclines upwards from the upper surface 14 at a 60° angle. The apertures 40 are respectively positioned 20cm, 40cm, 120cm and 140cm from the end 18 on both sides 28, 30 of the body portion 22.

The upper surface 14a of the body portion 22 includes 3 parallel upturned ribs 40. Each rib 40 runs substantially the entire length of the body portion 22, is 12mm wide and extends 5-6mm above the upper surface 14a. The lower surface 16b of the head portion 24 includes downturned ribs 44a, 44b respectively extending from the comers 46, 48 towards the neck portion 26.

Each rib 44 is 4mm wide, and extends 25mm below the lower surface 16b adjacent the neck portion 26, tapering to 15mm adjacent the corners 46,48. Similarly the ribs 50a, 50b, 50c are 25mm high and 4mm wide. The ribs 50a, 50b extend 25mm above the upper surface 14a the end 18 and slope continuously downwards along the sides of the sheet 12 so that the ribs 50a, 50b extend 25mm below the lower surface 16b at the neck portion 26. The ribs 50a, 50b then taper down to 15mm adjacent the comers 46,48. The rib 50d at the end 20 is 4mm wide and 15mm high.

It should be understood that the ribs 42 may be positioned on the lower surface 14b of the body portion 22 and may adopt some orientation other than the described above. Similarly, the ribs 44 may be positioned on the upper surface 16a of the head portion 24 and may adopt some orientation other than that described above.

One such variation is shown in Figure 5. As shown therein, the lower surface 16b of the head portion 24 is provided with reinforcing ribbing comprising ribs 52a, 52b extending downwards from the lower surface 16b of the head portion 24. However, in contrast to the ribs 44a, 44b, the ribs 52a, 52b extend outwards from a common point along the end 20 and respectively terminate at points on the lower surface 16b adjacent the sides 36,38 of the neck portion 26. To support the comers 46,48 of the head portion 24, the lower surface 16b also includes ribs 52c, 52d respectively extending inwards from opposite comers 46,48 and intersecting with the ribs 52c, 52d.

The description of the preferred embodiment is intended to be illustrative, rather than exhaustive, of the present invention. Those of ordinary skill will be able to make certain additions, deletions, and/or modifications to the embodiment disclosed herein without departing from the spirit or scope of the invention, as defined by the appended claims.