DRE skill trainer

This is a custom skill trainer for doing digital rectal exams.  It was created by the staff at the CSSU at Flinders School of Medicine before my time, but I rebuilt it a few years ago with some various improvements.

The idea is to practice the finger sweep necessary for a DRE and to be able to describe what is felt in a standardised way.

Construction is based around some PVC plumbing parts (gutter downspout and 1″ pvc pipe) with various objects at different places to be found and described.  A balloon is placed over the mouth of the pipe and extended down into the pipe.  A lubricated, gloved finger into the balloon provides a surprisingly good analogue to the real thing.

We have two sets of two gutters with three practice holes each (total of 6 different holes).  The gutter is ~750mm long with the tubes spaced ~230mm apart (one in the centre).  These are not critical dimensions.  Do what suits you for storage, portability and student access.

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Each tube is 25mm (1″) nominal size.  This means an OD of ~33.5mm and varying ID depending on the pressure rating or schedule.  This can range from 30.45 to 28.05mm ID  The thinnest pipe is fine for this application.  The tube lengths are about 115-120mm.  Again, this dimension is not critical.  Ours extend past the gutter by a centimeter or two.  An oversized hole (~35mm) is drilled into one side of the gutter.  The tube is held in by a bolt (1/4″ x 60mm) cross drilled through both parts near the bottom.  The bolt size was driven by the availability of the dome nuts.  I got bolts to fit the nuts.  You don’t have to use dome (acorn) nuts, but I think they make a neat finish.

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Previously, these tubes were glued to the gutter section, but this made maintenance very difficult.  The drawback to using bolts and nuts to hold the tubes in is a compromise on horizontal use and stacking for storage.

Inside each tube, there is a different arrangement of things to feel.  The first two are single 3/16″ dome nuts (with short bolt) at two different angles and depths (65mm and 75mm from the top of the tube).

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The third hole/tube simulates a fistula with a hole off to the side using a 1″ PVC Tee piece.  Construction of this one requires a slightly larger hole in the top to accommodate the Tee fitting OD and another hole in the bottom to allow for assembly.  Place the Tee in the gutter sticking through the upper hole.  Then insert the length of tubing through the bottom hole and secure with the bolt.  I recommend placing this one near the end of the gutter section for ease of assembly.  No glue is required.

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The next tube has two nuts at different angles and depths. 40mm deep at 45º and 70mm deep at 135º.

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The next tube has a lady bug decoration glued into the tube at a random angle.  This provides a different shape to describe, and has a groove along the top edge to simulate a prostate.  Something about this size with a groove – be creative!

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The final tube is lined with some anesthetic corrugated hose to provide yet another texture to describe.  We often put a lump of bluetack in the balloon in either this one or the one with the ladybug to simulate some poo.  Being in the balloon, the bluetack is mobile and can be easily replaced.  All the balloons do have to be replaced regularly when they break (every ~8-16 students).

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The following text is placed on the table as “answers” by each tube that students can uncover to check their description.

Station 1:
There is an object that protrudes <1cm from the side of the pipe.
It is 9mm wide and the tip is rounded and firm for the first 5mm.  Then the sides are sharp and angulated.    It is mobile.
It starts 5.5cm from the opening (it was screwed in at the 6cm mark)
It is a “dome” nut.
Clearly it is important to know the length of your index finger.  Measure your finger.
Check it out again and get a feel of how far 5.5 and 6cms are.

Station 2:
It is very important to be able to accurately describe the location of an abnormality.  The current practice in Australia is to use the clockface and the distance from the anal margin.
If the back of the patient is 6 o’clock, then their front is 12 o’clock, their right is 9 and their left is 3.
Please see whiteboard.
There is an object that protrudes <1cm from the side of the pipe.
It is 9mm wide and the tip is rounded and firm for the first 5mm.  Then the sides are sharp and angulated.    It is mobile.
It starts 6.5cm from the opening (it was screwed in at the 7cm mark)
It is also a “dome” nut.
The end of the nut is at 9 o’clock, 7cm from the opening.
In station 1, the end of the nut was at 12 o’clock

Station 3:
The pipe has an opening at 3 o’clock, 3cm from the opening.
The opening is about 2.5 cm wide, circular in shape and has a firm edge.
It goes from about 1 o’clock to 5 o’clock.

Station 4:
There is a lump on the side of the pipe at the 12 o’clock position (in D4 but about 11 o’clock in C4).
It starts at about 2cm from the opening.
Closest to the opening, there are two lobes separated by a groove in the centre. The lobes are symmetrical and increase in width from where they start to about 1cm wide each at the widest (3cm from the opening) with a total width of 2.2cm.
These lobes end in a groove running across the lump followed by a lobe 1cm by 1.5cm. This lobe finishes with a knob of 7mm by 5mm.
Total length of 5cm
It has the same consistency in all lobes: firm, hard with a smooth surface but rougher at the top. It is not mobile.

Station 5:
There are two lesions
Finding one lesion doesn’t mean the end of the examination, you must complete a thorough examination.
The two lesions are at:
4cm at 7o’clock
7cm at 11 o’clock

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