Rehana Shafi Kamal  ( Anaesthesiology Department, The Aga Khan University Hospital, Karachi. )

The use of Regional Anaesthesia and Nerve Blocks is becoming more popular and recognized as an effective means for providing anaesthesia for minor surgery. When used optimally, Regional An­aesthesia and local blocks can provide ideal opera­tive conditions. Successful outcome of the technique de­pends on injection of the local anaesthetic solution as near the target nerve as possible. It is therefore essential to know the detailed surface anatomy of the area. It is also important to know the phar­macological actions of the various drugs used. If the general principles and guidelines of Regional Anaesthesia are strictly adhered to, then regional anaesthetic techniques can provide a safe, cheap and effective means of anaesthesia for minor surgery. A few techniques of Regional Anaesthesia are described, which can safely be used by the general physician in an out-patient and day care surgery unit. The skill required to use these local analgesic techniques is not very difficult to learn, but it does need practice.

1. Anatomy:
The subcutaneous nerves of the relevant sen­sory nerves, are present in the cutaneous and subcutaneous tissues.
2. Equipment:
10-20 ml. syringe.
22-23 gauge fine bore needle.
Spinal needles are ideal if large areas are to be infiltrated.
3. Local Anaesthetic Solution Dose:
Dose depends on the size of tumor and ex­tent of the excision.
Dilute solutions are sufficient.
Minor excision: 5-30 ml. Lignocaine 0.25-0.5% with adrenaline 1:200,000.
More extensive excisions:
30-100 ml. Lignocaine 0.25% with Adrena­line 1:200,000.
or
30-50 ml. Lignocaine 0.5% with Adrenaline
1:200,000.
4. Indications:
Minor surgical operations, i.e., excision of
small tumors, incision of abscesses, suturing of wounds, etc.
5. Contraindications:
There are no specific contraindications, but infiltration anaesthesia should be avoided in:
a. Very apprehensive patients.
b. Patients who have had reaction to Lo­cal Anaesthesia in any previous occa­sion.
c. In small children.
d. Injection into infected tissues.
When injecting local anaesthesia in tissues supplied with end arteries i.e., toes, fingers and penis, vaso-constrictor substances i.e., adrenaline should not be used.
Technique
Patient should be lying in the supine position and as comfortable as possible. Only the area to be operated upon should be exposed. For removal of cutaneous or subcutaneous tumors, local anaestheticis injected from two poin­ts A and B, one above and one below the tumor. Injection is given in a fanwise manner on either sides of the tumor. (Figure 1).

To prevent intravascular injection, aspirate before injecting the local anaesthetic solution. On­set of analgesia is 3-5 minutes.
For Incision of Abscess
Using a 23 G needle inject a small amount 05-2 ml of the Local Anaesthetic solution where the abscess is pointing. Injection should be given slowly to minimize pain. Size of the raised weal should be of sufficient size for a painless incision (Figure 2).

1. Anatomy:
Layers of the scalp are as follows:
Skin, subcutaneous tissue, epicranial apo­neurosis and epicranium. Bulk of the nerves and vessels are situated above the epicranial aponeurosis.
2. Equipment:
10-20  ml syringe.
22-23  G needle.
For extensive infiltration, spinal needles are used.
3. Local Anaesthetic Solutions
As the scalp is a very vascular area, it is advisable to use vasoconstriction agents i.e., adrenaline with the Local Anaesthetic used. Minor Lesions 5 - 30 ml lignocaine 0.25% with adrenaline 1:200,000. 5 - 15 ml lignocaine 0.5% with adrenaline 1:200,000. Extensive lesions 30-100  ml lignocaine 0.25% with adrenaline 1:200,000. 30-50  ml lignocaine 0.5% with adrenaline 1:200,000.
4. Indications
a. Suturing of lacreations of the scalp.
b. As an adjunct to General Anaesthesia for intracranial operations, especially in patients with Head Injury.
5. Contraindications
Only the general contraindications ap­ply, there is no contraindication for lo­cal anaesthesia of the scalp.
Technique
Injections are made on either sides of the lacreations. Needle is placed in the subcutaneous tissue above the epicranialaponeurosis and pushed in horizontally along the length of the lacreation. Solution is injected as the needle is slowly with­drawn. A second injection is then made below the epicranial aponeurosis and solution injected in a similar manner (Figure 3). Aspirate before injecting, to prevent iñtrava­scular injection. It is important to inject the local anaesthetic solution both above and below the epicranial apo­neurosis. If the tissues under the epicranial apo­neurosis alone are infiltrated, the analgesia is not satisfactory, and the haemostatic effects of adrena­line are not obtained. Excellent analgesia and baemostatis are ob­tained if the solution is injected on two layers as described above (Figure 3).