The combination of spinal with epidural anaesthesia has the potential to eliminate or reduce these problems (Chapter 6). Hanaoka's needle is one such needle combination designed for continuous spinal epidural anaesthesia (CSE) (Chapter 51). These needles are disposable and consist of spinal and epidural components which allow practically simultaneous spinal injection and epidural catheterisation (Figure 54.1).
The technique for the insertion of the needle is as follows (Chapter 62):
1. The disposable epidural needle (17G) is inserted into the epidural space using a standard epidural anaesthesia technique.
2. The disposable spinal needle (26G) is now inserted through the epidural needle and advanced until the tip of the spinal needle exits through the back-hole ("rear eye") of the epidural needle and punctures the arachnoid membrane (Figure 54.2). The spinal needle is 7 mm longer than the epidural needle (Chapter 59).
3. A subarachnoid dose of local anesthetic is injected through the spinal needle (Chapter 61).
4. The spinal needle is removed.
5. The epidural catheter is advanced down the epidural needle.
5. The epidural needle is removed and the catheter is taped to the patient's skin.
The advantages of this technique are that:
1. The spinal component of the anaesthetic leads to the rapid onset of surgical anaesthesia with good muscle relaxation.
2. Continuous epidural anesthesia is available when surgery is prolonged or the height or depth of the spinal anesthetic is insufficient.
3. Local anaesthetic toxicity is less likely because smaller amounts of drug are required.