GB2324902A - Simulators - Google Patents

Abstract

A surgical simulator includes a simulation torso (10) formed with a thoracic cavity (19) within which simulation organs (23, 24) are located. The thoracic cavity (19) is closed by a thoracic plate (13) formed with an opening (18) through which access can be obtained to the simulation organs (23, 24). The opening (18) is initially closed by a polymeric pad (16).

Description

SIMULATORS Field of the Invention This invention relates to simulators for use by surgeons in practising heart surgery and has been developed in connection with the provision of a simulator for use by surgeons when carrying out simulation minimally invasive heart surgery operations. The simulator can, however, also be used for the carrying out of simulation open heart surgery operations.

Summarv of the Invention According to the present invention there is provided a surgical simulator comprising a simulation torso which includes a thoracic cavity within which simulation organs can be located, a thoracic plate for closing the thoracic cavity, which thoracic plate is formed with an opening through which access can be obtained to the simulation organs, and a polymeric pad for closing said opening.

A simulation sternum is preferably removably mounted on the thoracic plate and positioned so that access thereto can be obtained through said opening after forming an incision in the polymeric pad.

A simulation rib cartilage is preferably also mounted on the thoracic plate so as to extend over the opening in the thoracic plate, access to the rib cartilage being obtained by forming an incision in the polymeric pad.

Pump means are preferably provided for effecting the flow of simulation blood through modified cardio-pulmonary bypass access cannulae, for placement into the simulated heart.

Other preferred features of the simulator and its method of use will be apparent from the following detailed description of one embodiment of simulator which is illustrated in the accompanying drawings.

Brief DescriDtiqn of the Drawings Figure 1 is a perspective view of a surgical simulator for use by surgeons when carrying out minimally invasive aortic or mitral valve surgical operations, Figure 2 is a perspective view of a removable breast plate assembly which forms part of the simulator shown in Figure 1, and Figure 3 is a perspective view of an operating module which forms part of the breast plate assembly of Figure 2.

Description of the Preferred Embodiment The simulator shown in the drawings has been designed to permit simulation of the principles of the key stages involved in carrying out minimally invasive mitral and aortic valve surgery using the transsternal and right parastemal approaches. It includes a polymeric torso 10 accurately reproducing the anatomy of the thorax, abdomen and upper aspect of the lower limbs of a 75 kg.

male. The torso 10 is mounted on a rigid supporting plinth and frame 11 which is designed to hold the torso 10 securely in the desired operating position. A permanent silicone moulding 12 covers the entire anterior aspect of the simulated torso 10 and represents the functionality and texture of the skin and subcutaneous tissues.

An opening is formed in the torso 10 and this opening can be closed by a removable thoracic plate 13, which is also covered with a simulated dermal layer formed from a suitable silicone. The thoracic plate 13 includes a rotary operating member 14 (see Figure 2) which is arranged to operate a pivot lock (not shown) located on the undersurface of the plate 13. The operating member 14 is located within the silicone dermal layer at the level of the navel and is rotatable by means of a T-bar (not shown). When it is desired to remove the thoracic plate 13 from the opening in the torso 10, the T-bar is engaged with the operating member 14 and is rotated until the thoracic plate 13 can be lifted clear of the torso 10.

The reverse sequence is adopted to lock the thoracic plate 13 in position.

The thoracic plate 13 carries two removable7 replaceable items. These are a translucent moulding 15 which is so made as to simulate the morphology and structure of the third and fourth costal cartilages and a soft polymeric pad 16. The moulding 15 is attached to the thoracic plate 13 by push-fitting the cartilage flanges 17 over permanently fixed clips (not shown) positioned adjacent an opening 18 formed in the thoracic plate 13. The soft polymeric pad 16 delineates the area of skin incision for opening the thoracic cavity by the transsternal or right parastemal approaches. The pad 16 is provided with integral locating clips which push-fit into preformed holes in the thoracic plate 13. The simulator is so designed that interchangeable thoracic plates 13 can be provided, to take account of alternative approaches to opening the thoracic cavity.

The torso 10 is formed with a moulded thoracic cavity indicated generally at 19 and containing the following components: a) a removable simulated sternum 20 which is attached to the torso 10 by means of nylon bolts 21 which pass through slots 22 in the sternum 20 (one adjacent each end of the sternum 20) and enter tapped apertures formed in the torso 10, b) a simulation 23 of the heart, great vessels and pericardium, this being in the form of a removable, disposable cartridge which push-locates in a silicone cavity representing the mediastinum, and c) simulations 24 of the right and left lungs fitted within silicone recesses representing the pleural cavities.

As an alternative to the arrangement shown in the drawings, each rib, rib cartilage and the sternum may be formed as separate removable elements.

The method of production of the heart involves moulding the heart from a resilient foamed latex rubber in two halves and handcolouring the moulded chambers before the two halves are fixed together. The heart, major vessels and coronary arteries have silicone latex applied to them by spraying, the final stage being the application of latex to simulate the pericardial sac.

The pericardial layer is applied to the heart such that it is in continuity with the outermost surface of the heart, but such that it can be incised, peeled back from the heart surface, and sutured to the polymeric pad 16.

The heart simulator provides the means to rehearse the sutured placement of prosthetic heart valves, thereby allowing surgeons to rehears the accurate placement of multiple sutures circumferentially into the simulated heart valve annuli.

The heart simulation 23 may also include simulation coronary arteries so that the simulator can be used for the carrying out of simulation coronary artery by-pass grafting operations.

The right and left-hand coronary arteries and their major subbranches are constructed as separate structures and applied to the surface of the moulded heart simulation. The arteries and major sub-branches are produced by dipping preformed aluminium wire (configured into the shapes of the relevant anatomically accurate arterial morphologies) into a foam latex mixture and then curing them in a convectionally assisted oven. The simulated arteries formed in this way are then gently removed by sliding them off the aluminium wire formers.

This feature permits the realistic rehearsal of coronary artery bypass grafting procedures, and the hollow nature of the simulated arteries also allows the simulated placement of intra-operative arterial shunts and grafts.

A pump housing 25 is located at the upper end of the simulator module. The housing 25 contains twin integral diaphragm pumps (not shown) which are powered by 6 volt dry-cell batteries and the pumps operate a simulated cardio-pulmonary by-pass circuit, the pumps being so controlled as to simulate the blood flow characteristics of the arterial and venous circuits of the bypass system. The two pumps are an arterial pump, which is connected to a modified arterial perfusion cannula, and a venous pump, which is connected to two venous cannulae. Operating/monitoring switches (not shown) for activation of the pumps are located on the front face of the pump housing 25 and are labelled appropriately.

The pump housing 25 also contains four storage wells which are accessible by means of a sliding door. Three of the wells contain the integral arterial and venous connector tubing/cannulae whilst the fourth contains modified cannulae for use with cardio pulmonary by-pass equipment.

Two reservoirs are located within the pump housing 25 and contain simulated blood solution designed to simulate the visual appearance of arterial and venous blood. Removable filler caps (not shown) are provided for the reservoirs, the level of liquid within each reservoir being indicated by an L.E.D. indicator and the reservoirs being provided with drainage tubes to permit emptying of the reservoirs when the simulator is not in use.

A stainless steel locking bar is located directly behind the pump housing 25 and, when tightened, serves to prevent rotation of the torso 10 about a generally horizontal axis.

The procedure for preparing for a simulation operation involves the following steps: 1. Remove the torso 10 from its carrying case and check that the plinth 11 is fully supported on a suitable flat surface.

2. Remove the thoracic plate 13 from the torso 10 by turning the rotary member 14, 3. Insert a heart module 23 into the central silicone recess within the thoracic cavity 19 ensuring that the simulated lungs 24 sit correctly around it.

4. Fit a simulated sternum 20 in position within the thoracic cavity 19 by means of the two nylon bolts 21.

5. Fit a rib cartilage assembly 15 across the right parastemal aperture by push-fitting the central holes of each cartilage end flange 17 over the related fixings.

6. Fix a skin module pad 16 to the thoracic plate 13 by means of nylon push fasteners on the undersurface of the pad 16, pushing each fastener in turn into its equivalent hole in the plate 13.

7. Relocate the thoracic plate 13 accurately in position so as to cover the thoracic cavity 19.

8. Rotate the torso 10 into the required position by first slackening the stainless steel locking bar located behind the pump housing 25 and then turning the torso by holding it by both shoulders. The locking bar is then tightened to lock the torso in the required position.

9. Remove the bypass cannulae from the pump housing 25.

If the surgical procedure is a simulated mitral valve operation, the operating sequence is as follows: a) make a 10cm. vertical incision in the thoracic skin pad 16, approximately in the middle of the right parastemal aspect, b) expose the third and fourth rib cartilages afforded by the moulding 15, c) cut both cartilages at their medial and lateral extremities, i.e. at the borders of the right parasternal aperture using rib shears, d) remove both resected rib cartridges from the operating site, e) place a Finochietto rib spreader within the parasternal aperture and open its jaws until they both contact the walls of the chest aperture ensuring that the rib spreader is firmly supported against the walls. This will create a surgical exposure of approximately 10 cms. x 8 cms. and the surgeon carrying out the procedure should not attempt to extend the jaw opening beyond this limit.

f) incise the simulated pericardium and suture the cut edges to the thoracic pad 16, g) place the venous and arterial bypass cannulae in the heart/great vessels and switch on the simulated bypass pump, h) effect access to the mitral valve through incisions in the atrium and interatrial septum, and i) undertake the desired mitral valve repair or replacement procedure.

If the surgical procedure is a simulated aortic valve operation, the operating sequence is as follows: a) make a 10 cm. transverse incision in the thoracic skin pad 16 at the level of the second rib space, i.e. corresponding approximately to the mid-line of the pad 16, b) expose the sternum 20 and transect it with either a Gigli saw or a pneumatic saw, c) place a Finochietto rib spreader between the cut edges of the sternum 20 and gently open its jaws until resistance is felt, and the rib spreader is securely supported in position.

This will create an exposure of approximately 8cms. long by 8 cms. wide and the surgeon carrying out the procedure should not attempt to extend the jaw opening beyond this limit, d) place the venous and arterial by-pass cannulae in the heart/great vessels and switch on the simulated by-pass pump, e) effect access to the aortic valve annulus by incision through the wall of the exposed ascending aorta, and f) carry out the venous repair or replacement procedure.

It is to be appreciated that the particular form of simulator illustrated in the drawings is but one possible embodiment of the invention and that the detailed procedures explained step-by-step above are giving purely to enable an appreciation to be obtained of the application of the invention and the practical benefits which can be obtained.

Claims (14)

Claims:

1. A surgical simulator comprising a simulation torso which includes a thoracic cavity within which simulation organs can be located7 a thoracic plate for closing the thoracic cavity, which thoracic plate is formed with an opening through which access can be obtained to the simulation organs, and a polymeric pad for closing said opening.

2. A surgical simulator as claimed in Claim 1, which includes a simulation sternum removably mounted on the thoracic plate.

3. A surgical simulator as claimed in Claim 2, in which the simulation sternum is positioned so that access thereto can be obtained through said opening after forming an incision in the polymeric pad.

4. A surgical simulator as claimed in Claim 1, in which a simulation rib cartilage is mounted on the thoracic plate so as to extend over the opening in the thoracic plate.

5. A surgical simulator as claimed in Claim 4, in which the simulation rib cage is so positioned that access thereto is obtained by forming an incision in the polymeric pad.

6. A surgical simulator as claimed in Claim 1, in which pump means are provided for effecting the flow of simulation blood through the organs in the thoracic cavity.

7. A surgical simulator as claimed in Claim 1, in which the simulation organs include a simulation heart formed from a resiliently deformable material on which suturing can be practised.

8. A surgical simulator as claimed in Claim 7, which includes moulded hollow simulation coronary arteries attached to the simulation heart.

9. A surgical simulator substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

10. A method of surgical training which includes the use of a surgical simulator comprising a surgical simulator which includes: a) a thoracic cavity within which simulation organs are located, b) a thoracic plate for closing the cavity, which thoracic plate is formed with an opening through which access can be obtained to the simulation organs, and c) a polymeric pad for closing said opening, said method including effecting an incision in the polymeric pad to obtain access to the simulation organs through the opening in the thoracic plate, and carrying out surgical procedures on said simulation organs.

11. A method as claimed in Claim 10, in which:a) the simulation organs include a simulation heart, b) a simulation sternum is mounted on the thoracic plate and is positioned so that access thereto is obtained through the opening in the thoracic plate, and c) a simulation rib cartilage is mounted on the thoracic plate so as to extend over the opening in the thoracic plate.

12. A method as claimed in Claim 11, which includes:a) making a vertical incision in the polymeric pad, b) exposing selected simulation rib cartilages, c) cutting said selected cartilages, and d) removing said resected cartilages from the operating site.

13. A method as claimed in Claim 11, which includes:- a) making a transverse incision in the polymeric pad, b) exposing the simulation sternum, c) transecting the sternum, and d) separating the cut edges of the sternum using a rib spreader.

14. A method of surgical training substantially as hereinbefore described with reference to the accompanying drawings.