The position of the patient on the operating table must be such as to facilitate access to the operative site(s) by the surgeon and to the patient's airway for the anaesthetist. It will also be dependent upon the type of surgery being performed, the position of the monitoring equipment and any intravenous devices in situ. It should not compromise the patient's circulation or respiratory system or cause damage to the skin or nerves.

Pre‐operative assessment will identify patients who may need extra precautions during positioning because of their weight, nutritional state, age, skin condition or pre‐existing disease. The increased numbers of obese patients requiring surgery present specific challenges, and staff must be familiar with the weight limits of patient trolleys and operating tables. Many departments now have specialist bariatric equipment for the safe positioning of obese patients (Fencl et al. [62]).

Pre‐existing conditions (such as backache or sciatica) can be exacerbated, particularly if the patient is in the lithotomy position (Figure 16.26), as the sciatic nerve can be compressed against the poles (AfPP [9]). Most post‐operative palsies are caused by incorrect positioning of the patient on the operating table (Beckett [29]). Consideration by and co‐operation of all theatre personnel can help to prevent many of the post‐operative complications related to intraoperative positioning; this remains a team responsibility (AfPP [9], Beckett [29]).

All movements of the limbs of the unconscious patient should take into account the anatomy and natural planes of movement of each limb to avoid stretching and pressure on the related nerve planes (AfPP [9]). Hyperabduction of the arm when placed on a board, for example, can stretch the brachial plexus, causing some post‐operative loss of sensation and reduced movement of the forearm, wrist and fingers. To prevent this, the board should be angled at 45° and not 90°, with the patient's hands facing more towards the feet rather than the head (Figure 16.27). The ulnar and radial nerves may be affected by direct pressure as a result of insufficient padding on arm supports.

Compartment syndrome is a serious complication of the Lloyd‐Davies position (Figure 16.28) and occurs when perfusion falls below tissue pressure in a closed anatomical space or compartment, such as a hand, forearm, buttock, leg, upper arm or foot. It develops through a combination of prolonged ischaemia and reperfusion of muscle within a tight osteofascial compartment (Schmidt [185]). Untreated, it can lead to necrosis, functional impairment, renal failure and death (Schinco and Hassid [184]).

If patients are placed in the Lloyd‐Davies position and Trendelenburg tilt for longer than 4 hours, it is recommended that their legs should be removed from the support every 2 hours, or as close to 2 hours as possible, for a short period of time to prevent reperfusion injury (Raza et al. [171]). However, approaches vary according to local hospital policy, and clinical decisions are based on the patient's co‐morbidity. Antiembolic stockings and intermittent compression devices used in the Lloyd‐Davies position must be carefully inspected during patient positioning. Otherwise, if the position is not implemented correctly, these devices may contribute to compartment syndrome (Malik et al. [117]). The use of these devices will depend on the clinical judgement of the surgeon and anaesthetist, the physical status of the patient, and the hospital protocol and recommendations.