Modified Lloyd-Davis position, aiming for hip flexion of 15 degrees and adequate leg abduction to gain vaginal access as needed
To reduce the risk of pressure sores the women can be placed directly on a gel mattress on the operating table, ensuring it is not creased beneath her.
Considerations for Positioning
Positioning requires clear communication between the anaesthetist and responsible surgeon as well as assistance from a sufficiently sized and skilled team of theatre staff trained in manual-handling. Positioning must take into consideration the need to avoid aorto-caval compression, which could compromise fetal well-being; ensure adequate intra-operative vaginal access to allow monitoring of PV bleeding and facilitate progression to hysterectomy if indicated; as well as anticipate a potentially prolonged surgery and thus the need to minimise the risk of associated venous thrombo-embolism (VTE), nerve injury or compartment syndrome from extended immobilisation.
The patient should be laid supine, with a 15-degree left lateral tilt. ‘Flowtrons’ (Arjo, Sweden) should be applied to both legs ensuring that tubing and adaptors are not lying under any part of the calf (this can cause pressure sores). The legs are then carefully placed into appropriately sized and positioned stirrups. The fit of the stirrups must be correct with no undue pressure on either the neck of fibula laterally or the medial tibial condyle, thus protecting the common peroneal and saphenous nerves from compression injury.
Once the lower limbs are secured, the stirrups should be slowly and simultaneously moved into a modified Lloyd-Davis position, aiming for hip flexion of 15 degrees and adequate leg abduction to gain vaginal access as needed. By comparison with lithotomy, the lesser degree of hip flexion in Lloyd-Davies reduces the risk of stretch injury to the sciatic and obturator nerves; as well as secondary compression of the femoral nerve as it passes under the inguinal ligament. Lloyd-Davies also generates less calf pressure, potentially reducing the risks of post-operative VTE and compartment syndrome.
'Well-Leg' Compartment Syndrome
This is a rare complication resulting from prolonged positioning in lithotomy for abdomino-pelvic surgery. The incidence varies from between 1:3500 to 1:100 yet it is often not considered by teams operating on women with PAS. Although it is caused by tissue hypoxia from prolonged positioning the the development of clinically detectable signs of acute WLCS typically follows re-perfusion hence only becomes identifiable after lowering legs to supine once the surgery is complete.
The symptoms may include the classic ‘five P’s’ of arterial insufficiency (pain, pallor, pulselessness, paraesthesia and poikilothermia) but often the main symptom is severe leg pain.
Any signs or symptoms of WLCS in a post-operative patient should prompt thorough neuro-vascular assessment of the lower limbs with an urgent referral to the vascular surgeons if there are any concerns at all.
Reducing the risk of pressure ulcers
Prolonged surgery risks the development of pressure ulcers. There are products on the market such as the HoverMatt which can be used for patient repositioning during surgery to ensure appropriate care of pressure areas. However, care must be taken with these surgical aids as some are capable of rapidly absorbing a large amount of fluid (e.g. PV bleeding) thereby risking underestimation of ongoing blood loss.
By carefully positioning the woman directly on a gel mattress ensuring there are no wet or creased areas underneath her, the risk of pressure sores is reduced. Under-buttock drapes should not be used as it significantly increased the risk of generating pressure areas (creases under the thighs, buttocks and lower back). Instead, a self-adhesive drape should be stuck to the leg drapes and the table between the legs to form a funnel into a bucket lined with a plastic bag so all blood lost vaginally can be easily collected and weighed.
In cases of suspected severe PAS, consideration should be given to a gentle speculum examination before starting surgery to:
Assess cervical and/or vaginal vascularity
See if there are signs of placental tissue adjacent to, or even breaching, the mucosa
Gauge the extent of bladder reflection and size of vaginal cuff required to control bleeding if proceeding to hysterectomy.
No digital examination should be performed due to the risk of bleeding.