Field of the Invention The invention relates to a medical apparatus and in particular to a medical apparatus for positioning limbs to facilitate medical procedures.

Background to the Invention When a medical practitioner is conducting a medical procedure on a person, it is frequently necessary to position a part of the person's body, for example a limb, to a desired location or position. Currently, the primary method for placing and subsequently retaining a limb in position is for a practitioner to use their hands.

However, this method makes medical procedures difficult, as the medical practitioner does not have full use of both hands.

One known solution to this problem is to use an assistant to retain the person's limb in position while the medical procedure is being carried out. However, the presence of this additional person can cause further problems. For example, the assistant may obstruct the medical practitioner during the procedure making it more difficult to perform the medical procedure. In addition, the assistant who is holding the person's limb in a specific position for an extended period of time may tire due to physical limitations, thereby causing a movement of the person's limb. Such movement of the limb may adversely affect the success of the medical procedure.

A further known solution is to use a mechanical harness to position a person's limb. However, these known mechanical harnesses are typically cumbersome and difficult to manoeuvre. In such harnesses the person's limb is typically held in a cup type attachment. A strap is then used to apply a circumferential force to the limb to hold it in position. The circumferential force being applied must be sufficient to prevent movement of the limb within the cup attachment. However, this force may cause

discomfort or even injury to the person and may also constrict blood circulation in the area causing further problems.

An example of a particular need for exact positioning of a person's limb is in the treatment of congenital dysphasia of the hip. This medical condition includes subluxation (partial dislocation) of the femoral head, acetabular dysplasia, and complete dislocation of the femoral head from the true acetabulum. Treatment of this condition requires the exact positioning of the femoral head at the hip by suitable manipulation and positioning of the leg. When the leg is correctly positioned, it must be maintained in this position for a period of time so a procedure can be carried out to rectify the condition.

For children under the age of six months, a'Pavlik Harness'can be used to position the limb in the correct orientation for the treatment of the condition. This type of harness is described in United States Patent No. 3,730, 177. The success rate of this harness is about 95%. For children who are older than six months, the success of the 'Pavlik Harness'decreases significantly. A child aged six to eighteen months with a dislocated hip will probably require closed manipulation or open reduction. The standard treatment for children older then six months usually involves adductor tentomy, closed reduction under general anaesthesia, an arthrogram and the application of a hip spica cast.

The application of a hip spica cast is a difficult procedure and has a number of draw backs. At least four people are required to perform the procedure, two to hold the child's legs, one to perform an arthrogram and one to apply the cast. The child's legs must first be positioned correctly. The child's legs and lower torso are then wrapped in preparation for the application of a cast. At all times during the application of the cast, the child's legs must by maintained in the correct position as set by the medical practitioner. The finger and hands of the person holding the child's legs can get in the way and effect the application of a pre-cast wrap and the cast. Due to physical limitations of the person holding the child's legs, the likelihood of accidental movement of the legs is quite high. This accidental movement can affect the success of the

procedure. It should be noted the person's legs must be retained in a steady/safe position for the entire procedure including the setting of the cast. After the application of the cast, the position of the fermoral head is checked radiologically. If the fermoral head is in the incorrect position, the procedure must be repeated after removing of the cast, thus extending the time required to complete the procedure. Longer procedures increase the risk to the child's health.

Accordingly, there is a need for an improved medical apparatus for positioning a person's limbs.

Summary of the Invention This need and others are met by the present invention in which, a first embodiment provides a limb positioning apparatus for use in positioning at least one limb of a person in a specific position the apparatus comprising a support frame having at least one articulating member attached thereto, each articulating member having a first end for attachment to the frame and a second end having a limb engagement means, the limb engagement means being provided with securing means adapted to maintain the limb within the limb engagement means, the limb engagement means being movable relative to the frame to place the limb in a fixed predefined position.

Preferably, the articulating member is adapted to facilitate the relative movement of the first end with respect to the second end in three-dimensions.

Conveniently, the articulating joints of the articulating member are sufficiently stiff so as in use to support and maintain the limb in a required position.

Preferably, the articulating member comprises a plurality of inter-engageable segments, the segments being moveable relative to one another.

Conveniently, the segments are connected by a ball and socket joint or any other segmented linkage.

Preferably, the securing means comprises force application members adapted to apply at least two substantially opposing forces transverse to the limb, in a region adjoining the end of the limb.

Conveniently, the force application members are interchangeably replaceable.

This permits the use of force application members of different sizes or shapes to suit the person's limb and position of engagement. The size and shape of the force application members are chosen so that they cause minimum interference during, for example, a medical procedure.

Preferably, the limb engagement means has a limb support portion to support the portion of the limb below a point of engagement between the patent's limb and the limb engagement members.

The articulating member may be fixed to the frame, at the first end, and the limb engagement means, at the second end, using an adhesive. Alternatively, the articulating member and limb engagement means are attached to the frame using screw-on fixtures.

Conveniently, the limb engagement means is applied to the distal end of the person's limb, the distal end being the end of the limb located away from a person's torso, so that unrestricted access is available to a medical practitioner working on the person's limb.

Preferably, the support frame is arranged with a support platform at one end of the frame and the articulating member attached at the opposing end. The support platform is formed to maintain the person in a comfortable, stable position which facilitates the performance of medical procedures. The platform may include a strap or harness arrangement capable of maintaining a person's torso in a fixed position relative to the support frame.

Preferably, the support platform is detachable from the support frame allowing for the platform and the person positioned thereon to be moved away from the person support frame.

Conveniently, the support platform may be formed of two or more parts which are releasably detachable from each other.

In one embodiment the support platform may be formed to match the shape of a person's body.

Ideally, the releasably detachable part of the support platform is disposable. The disposable part of the platform may therefore be enclosed by a bandage, cast or the like and detached from the support platform with the person. This may then be replaced by a new disposable detachable part for example for the next person.

Preferably, the limb positioning apparatus is fabricated from a material, for example plastic, which permits the use of X-rays, MR scanning or the like so that accurate medical information can be obtained from a person while held by the limb positioning apparatus.

Preferably, the limb positioning apparatus comprises two articulating members with limb engagement means. This enables a user to position two limbs simultaneously.

According to a second embodiment of the invention there is provided a method of positioning a person's limb using a limb positioning apparatus comprising the following steps: positioning a portion of a person's limb into a limb engagement means of the limb positioning apparatus; applying a force to the limb by means of a pair of force application members; and

positioning the person's limb in a required position by moving an articulating member which supports the limb engagement means with the person's limb held therein.

In a further embodiment of the invention a method is provided for applying a hip spica cast using a limb positioning apparatus including the steps of : positioning a person in a specific position for the use of a limb positioning apparatus; placing a portion of the person's limb into a limb engagement means; retaining the person's limb in the limb engagement means by the use of force application members; positioning the person's limb in an appropriate orientation for the application of a hip spica cast by adjusting the articulating member supporting the person's limb in the limb engagement means; checking the position of the person's limb using for example an arthrogram or the like; wrapping the person's limbs and lower torso in a pre-cast wrap; checking the position of the persons limb using for example an arthrogram or the like; applying a cast to the person's limbs and torso; allowing the cast to set;

releasing the force application members from the person's limb; and removing the person from the limb positioning apparatus by: releasing the force application members; removing the limb engagement means; and sliding the person off the support platform.

The limb positioning apparatus may be used in various medical procedures including for example but not limited to, direct visual examinations, endoscopic procedures, instillation of radiological contrast, open surgical procedures in the pelvis and perineum, biopsies, and anal/genital reconstructions. Such medical procedures usually involve the urethra, bladder, ureter, vagina, uterus, anus, rectum and colon.

The invention is particularly suited for use with children because a lower degree of support is required to be provided by the articulating member than in the case of an adult. The weight which the articulating member may support must be balanced against the ability of a user to move the articulating member. If the articulating member is excessively stiff in order to support a limb of an adult it will make the positioning of the limb engagement means difficult.

Conveniently, the limb positioning apparatus may be used to position different limbs of a person. These include a person's upper and lower leg and their arm.

Brief Description of the Drawings The invention will now be described in greater detail with reference to the accompanying drawings in which; Figure 1 is a perspective view of an limb positioning apparatus according to the invention; Figure 2 is an elevation of the limb positioning apparatus of Figure 1;

Figure 3 is a plan view of the limb engagement means of figure 1; and Figure 4 is an end view of the limb positioning apparatus of Figure 1.

Detailed Description of the Drawings Referring to Figures 1 to 4, there is illustrated an limb positioning apparatus 1 for use in positioning a person's limb (s), in the example shown a child's legs, in a specific position to facilitate medical procedures to be carried out. The apparatus 1 comprises at least one, and in the exemplary embodiment illustrated two, articulating member 2 having a first end 21 and a second end 22. The first end 21 is adapted for attachment to a support means which, in this embodiment of the invention, is a support frame 3. On the second end 22 a limb engagement means 4 is provided for engaging with a limb L of a person P.

The articulating member 2 can place the limb engagement means 4 in a specified position in a 3-dimensional area depending upon the requirements of a user. The articulating member 2 is sufficiently stiff so as to support and maintain a limb L in a required position as specified by the user. The articulating member 2 is suitably comprised of a series of interengageable segments 23 moveable relative to one another.

The segments 23 are connected by ball 24 and socket joints 25 permitting multi directional movement between each segment 23 in three dimensions. Each segment 23 comprises a ball and socket separated by a short tubular section. Each ball engages with the corresponding socket of an adjoining segment of the articulating member 2.

The limb engagement means 4 has a set of force application members 41 which may engage and hold a person's limb L. The force engagement members 41 are adapted to apply at least two substantially opposing forces transverse to the limb L, in a region adjoining the end of the limb L. The force engagement members 41 are interchangeably replaceable permitting the use of force engagement members 41 of different sizes or shapes to suit the persons limb L and position of engagement. The size and shape of the

members are chosen so that they cause minimum interference during, for example, a medical procedure. The limb engagement means 4 also includes a limb support plate 42 to support the portion of the limb L located below the limb engagement members 41.

The limb engagement means 4 is applied to the distal end of the person's limb L, the distal end being the end of the limb located away from a person's torso, so that unrestricted access is available to a medical practitioner working on the person's limb L.

A platform 5, 5A is attached to the associated support frame 3 and is used to support a person P on the limb positioning apparatus 1. The platform 5, 5A is formed from at least two parts, including main support platforms 5 and an elongate support plate 5A. The elongate support plate 5A is realeasably detachable from the main support platform 5 and frame 3. The elongate support plate SA is supported on a pillar member 31. The pillar member 31 is releasably engagable with the support frame 3. A strap or harness arrangement (not shown) can be used to maintain the person's torso in a fixed position relative to the associated support frame 3 during a medical procedure. The person support platform SA, when detached from the support frame 3, allows for the person P positioned thereon to be moved away from the limb positioning apparatus 1 while still being supported by the platform SA.

The limb positioning apparatus 1 is primarily used to position a person's limb L which may be carried out in the following way. A person P is positioned on the support platform 5, 5A and using a strap or harness arrangement (not shown) is retained in position upon the limb positioning apparatus 1. A portion of the person's limb L is then positioned into the limb engagement means 4. The force application members 41 are then adjusted to apply a holding force to act upon the person's limb L. The person's limb L is also supported by the limb support plate 42. The limb support plate 42 assists in supporting the person's limb thereby reducing the force required to be applied by the force application members 41. A limb positioning apparatus user may then position the person's limb L in a specific position by moving the limb engagement means 4, with the portion of the person's limb L held therein, into the required position for carrying out a medical procedure. Upon positioning of the limb L the user can release the limb engagement means 4 which is attached to the articulating member 2. The limb L will

remain in the position set by the user as the segments 23 of the articulating member 2 are sufficiently stiff to prevent movement of the limb L. With the limb L held in position the user is free to carry out a medical procedure without having to hold the person's limb L.

The articulating member 41 may be fixed to the frame 3, at the first end 21, and the limb engagement means 4, at the second end 22, using an adhesive. Alternatively, the articulating member 41 and limb engagement means 4 are attached to the frame 3 using screw-on fixtures.

In one embodiment, the support platform 5, SA may be suitably formed so as to match the shape of a person's body. The releasably detachable part of the support platform SA may be disposable. In this way, the releasably detachable part SA may be enclosed by a bandage, cast or the like and detached from the support platform 5 with the person. This part may then be replaced by a new disposable detachable part for use with the next person.

There is also provided a method of applying a hip spica cast for the treatment of congenital dysplasia of the hip using a limb positioning apparatus which includes the following additional steps. With the person's limb L in the correct/'Safe'position, which is maintained by the limb engagement means 4, a user can apply a hip spica cast to a persons limb by wrapping a person's limb and lower torso in a pre-cast wrap. A plaster-of-paris cast is then applied to the person's limb and torso. The cast is then allowed to set. The force application members are then released from the person's limb and the person from the limb positioning apparatus.

The words"comprises/comprising"and the words"having/including"when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.