Prone position

(Figure 98)

• Transfer the patient on to the operating table in the prone position. This requires rolling the patient from the supine position on to the arms of three or more assistants, who then lift the patient on to the operating table

• In the prone position the patient must have their chest and pelvis supported so as to allow free movement of the abdomen. This may be achieved by lifting the patient on to a special mattress (e.g. the Montreal mattress) or frame (e.g. the Railton–Hall frame)

• Rest the head on a suitable support (e.g. a pillow or a head ring)

• Abduct the shoulders 90° and flex the elbows 90° so that the arms lie supported on a suitable arm board (move the arms through into position from the side in a front crawl swimming motion).

Considerations

• Ensure that any pressure areas are well-padded: the knees, the pelvis, the external genitalia, the chest, the arms, the forehead.

• Pad and tape the eyes.

• The arms are best positioned on an arm board with the shoulders abducted 90° and the elbows flexed 90°.

• Flex the knees slightly (e.g. over a pillow) to relieve tension on the sciatic nerves.

Prone position

(Figures 100 and 101)

• Transfer the patient on to the operating table in the prone position. This requires rolling the patient from the supine position on to the arms of three or more assistants, who then lift the patient on to the operating table

• In the prone position the patient must have their chest and pelvis supported so as to allow free movement of the abdomen. This may be achieved by lifting the patient on to a special mattress (e.g. the Montreal mattress) or frame (e.g. the Railton–Hall frame)

• Rest the head on a suitable support (e.g. a pillow or a head ring)

• Abduct the shoulders 90° and flex the elbows 90° so that the arms lie supported on a suitable arm board (move the arms through into position from the side in a front crawl swimming motion).

Montreal mattress (Figure 101): a shaped mattress with a central cut-out for the abdomen so that the abdomen can lie free, which allows venous drainage into the inferior vena cava and thus reduces venous plexus filling around the spinal cord.

Railton–Hall frame: a frame with four hinged pads that support the chest and pelvis in the prone position, allowing the abdomen to lie free.

Supine position

(Figures 92 and 93)

• Supine position on a standard operating table (may need to be radiolucent)

• Dorsomedial approaches. The leg naturally lies in slight external rotation when a patient is supine (see Figure 86). To increase external rotation, the figure-of-4 position may be used (see Figure 88)

• Lateral and anterolateral approaches to the hindfoot, and dorsolateral approaches to the mid-foot and forefoot. Place a sandbag under the buttock to help internally rotate the leg (see Figure 87). The access may be improved further by placing a side support against the opposite iliac crest and then tilting the table 20–30° towards the opposite side

• Dorsal approaches to the midfoot and forefoot. Rex the knee so that the foot lies with its sole on the table (plantigrade) (Figure 92). This position may be maintained by placing one or more pillows behind the knee

• Plantar approaches (Figure 93). Sit at the end of the table with the table raised. The table may also be tilted head-down (Trendelenburg position).

Considerations

• Ensure that any pressure areas are well-padded: the occiput, the sacral area, the heels.

• A thigh tourniquet may be used.

• Drape the leg free to allow full hip, knee and ankle movement.