Patient Positioning

Flexion of the patient’s spine

In order to place a spinal needle or catheter, or an epidural, it is necessary to have adequate flexion of the patient’s spine. Abolishing the natural lumbar lordosis increases the aperture between the vertebrae for passage of the needle (Fig 1).

Patient sitting or lying down

Patient awake or asleep

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Fig 1 A model spine demonstration, showing difference between flexed and extended positions. In the lateral views (top), the gap between spinous processes can be seen to increase on flexion and in the posterior view (bottom), the available aperture between articular processes can be seen to increase. The L2/3 interspace is indicated in each photo for comparison (© Taylor & Francis 2005).

Flexion of the patient’s spine

Patient sitting or lying down

Neuraxial blocks can be performed with the patient in a sitting or in lateral position, depending on operator preference and patient ability. The sitting position confers the advantage of making the midline easier to identify, particularly in obese patients. It also increases hydrostatic pressure in the cerebrospinal fluid, which may make spinal needle placement and fluid aspiration easier. Practitioners should be able to perform blocks in either position (Fig 2).

Patient awake or asleep

Fig 2 Positioning for neuraxial block. The lumbar spinous processes are clearly visible in this patient (left) and the lumbar lordosis has been reversed (right). The same result can be achieved in the lateral position. (Image by author, © Taylor & Francis 2005).

Flexion of the patient’s spine

Patient sitting or lying down

Patient awake or asleep

Most often, neuraxial blockade is performed with the patient awake. This is to enable the patient’s cooperation in achieving correct positioning, and to enable the patient to report any immediate complications of the procedure. Conscious sedation may be used in anxious patients. Epidural and caudal techniques are sometimes used once general anaesthesia has been administered, particularly in children or extremely anxious adults.