Premedication
A mild sedative may be beneficial for anxious patients having surgery under local anaesthesia. Temazepam 10 mg orally, 2 hours before operation, is usually sufficient. An alternative is intravenous propofol. Day patients are advised not to travel home alone if they have had premedication. Other premedication drugs may be used.
Local anaesthesia
Anaesthetic eye drops such as amethocaine 1% or oxybuprocaine (Benoxinate) 0.4% are given before skin preparation.
Lignocaine (xylocaine, lidocaine) 2% with 1 : 80,000 or 1 : 200,000 adrenaline gives excellent anaesthesia for local infiltration or regional block. After injection the anaesthetic is effective within 5 minutes and lasts for about an hour. A mixture of equal volumes of lignocaine and bupivacaine (Marcaine) 0.5% prolongs the anaesthesia. The addition of hyaluronidase promotes diffusion of the anaesthetic but increases its absorption and is generally not necessary. The adrenaline improves haemostasis. Warming the anaesthetic to body temperature reduces the discomfort of the injection.
Local infiltration
4.1
Subcutaneous approach
Having marked the incision, inject local anaesthetic slowly into the subcutaneous layer (and the submuscular layer for deeper dissection) deep to the mark. Alternatively, inject a bolus of anaesthetic laterally and massage it across the lid. Large volumes are not required and they distort the tissues.
4.2
Subconjunctival approach
If a posterior approach is used, inject deep to the conjunctiva along the proximal border of the tarsal plate. This can also be a useful approach to start anaesthesia before injection under the skin.
4.3
Tumescent local anaesthesia
Tumescent anaesthesia is the injection of larger volumes of very dilute local anaesthetic, epinephrine and sodium bicarbonate into the tissues until it becomes firm (tumescent). Hyaluronidase is not used. Anaesthesia is effective and blood loss is reduced. It is indicated for larger surgical fields than the immediate periocular region, such as the forehead in a forehead lift or the abdominal wall in autogenous fat harvesting. Lignocaine is absorbed more slowly when tumescent anaesthesia is used.
Local infiltration
4.1
Subcutaneous approach
Having marked the incision, inject local anaesthetic slowly into the subcutaneous layer (and the submuscular layer for deeper dissection) deep to the mark. Alternatively, inject a bolus of anaesthetic laterally and massage it across the lid. Large volumes are not required and they distort the tissues.
