The scalp donor involves the occipital, parietal, and a part of the temporal area. The recipient area is usually the frontal and mid-scalp region, extending to the vertex in some cases.
The field block, peripheral nerve block, and tumescence anaesthesia are used for anaesthetising the scalp in the hair transplant procedure.
The field blocks
The field block is the infiltration of anaesthetic solutions around nerves near the operative field. In the recipient area, the nerve supply is from anterior to posterior, so the infiltration of the anaesthetic solution is anterior to the anterior hairline. In the scalp donor area, the nerve supply is inferior to superior in the occipital region, so the anaesthetic solution is injected inferior to the donor area.
The peripheral Nerve Blocks (Nerve Blocks)
The peripheral nerve block is the infiltration of a small amount of anaesthetic solution around the nerve trunk. For the donor area, the local anaesthetic agent is injected around the greater and lesser occipital nerve.
In the scalp recipient area, the solution is injected around supratrochlear, supraorbital, and zygomaticotemporal nerves.
The Tumescence Anesthesia
Tumescence anaesthesia is the infiltration of a relatively large volume of dilute anaesthetic solution in the entire operative area. The tumescence infiltration reduces the total amount of anaesthetic agent used, gives more extended period of smooth anaesthesia.
PREPARATION OF LOCAL ANAESTHETIC SOLUTION
Lidocaine 2% —————20 ml
Ropivacaine0.5 % or Bupivacaine 0.5% ——–20 ml
Normal saline ————–40 ml
Adrenaline(1:1000) —— 0.5ml
TOTAL – 80ml solution having 1% lidocaine, 0.25%Bupivacaine/ropivacaine.
The individual surgeon can change the concentration of the anaesthetic agent, but the total safe dose of each anaesthetic solution shall not be exceeded. This solution is used for field blocks and peripheral nerve blocks.
Technique of Giving Peripheral Nerve Blocks
SCALP DONOR AREA
1. The anaesthetic solution is filled in either an insulin syringe or a 3cc liver lock syringe with a 30 G hypodermic needle.
2. The area is ice-cooled.
3. The injection sites for greater occipital nerve and lesser occipital Nerves are marked. by keeping the three fingers, index, middle, and ring finger together vertically at the level of superior nuchal line over occipital protuberance, in the prone position.
4. The vibrator tip is put near the injection site and informs the patient about vibrator and injection, keeping a watch over his pulse and also talking to the patient.
5. The solution is injected in a subcutaneous plane to create a wheel on both sideswhich means just lateral to index and ring finger after a few minutes pass the needle through the wheel and infiltrate the solution around both greater occipital nerves.
6. Similarly, infiltrate around the lesser occipital nerve.
The author also gives field blocks just inferior to the safe donor area of the lower border of the strip area. The same solution is injected using a 26G needle at a superficial dermal level. All precautions are taken not to inject intra vascular. The infiltration shall be slowly, using a vibrator during injections.
NERVE BLOCK FOR SCALP RECIPIENT AREA.
The supratrochlear and supraorbital nerves innervate the majority of the scalp recipient area. Another nerve is the zygomaticotemporal nerve.
The Supraorbital and supratrochlear nerve block
The patient is kept in a supine position.
He is informed about the injection and the use of a vibrator. The patient shall be informed that the injection is not going to hurt his eyes and shall keep himself calm and should not frown during the injection. Keep a watch over his pulse and talk to him to avoid vasovagal shock.
Put three fingers index, middle, and ring finger together over the forehead. The middle finger is in between the eyebrows. Palpate the supraorbital notch on the lateral side of the index and ring finger.
After the care-full location of the supraorbital notch, using 30 G needle or insulin syringe inject around 1ml anaesthetic solution near the supraorbital and supratrochlear nerves on both sides. It is vital to be precise that do not inject in the supraorbital foramen and intra vascular.
Wait for some time to see the effect.
Alternatively or also, the injection can be given in a subcutaneous plane, horizontally above the supraorbital and supratrochlear nerve on both sides.