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Era of Operative Nerve Blocks
JP Arora
Introduction
Regional anaesthesia is a broad term that
includes spinal and epidural anaesthesia as well as peripheral nerve blocks. Most of the time one equates regional anaesthesia with the centrineural axis blocks. While most anaesthesiologists, surgeons and other doctors are aware that it is possible to do surgery under nerve blocks, somehow it does not gain the mileage it deserves. With emerging pain clinics the interest in nerve blocks is somewhat more now.
This article aims at enumerating the various nerve blocks documented with their indications. It is extremely useful to have alternatives to general anaesthesia in case of medically high risk patients. Operations can be performed literally from head to toe with the help of these blocks. The main usefulness of nerve blocks today is in this era of day care surgery. Local anaesthesia with nerve blocks contributes in a big way towards patients going home pain free few hours after surgery.
Indications and advantages
1) High risk patients with serious cardiovascular or respiratory problems
2) Small nursing homes with lesser facilities
3) Economical
4) Patient willingness to receive regional anaesthesia
5) Outpatient and day care surgery
6) Surgeon acceptance of the technique
7) A patient with full stomach
Contraindications and Disadvantages
1) Coagulation disorders
2) Infection at the site of nerve block
3) Known hypersensitivity to local anaesthetics
4) Mentally disturbed patients
5) Neurological disorders (Medicolegal problems)
6) Septicaemia
7) Multiple operations
More and more surgical operations are being done on an outpatient basis with successful peripheral nerve blocks. Not only is the operation and post operative course pain free there is also minimum disturbance to the patient’s vital status. Patients are very comfortable in the relaxing confines of their home and recovers faster from the stress.
Drugs
1) Lignocaine-commonly used
2) Sensorcain-commonly used
4) Tetracain-yet to come to India
5) Ropivacain- It is available thought not commonly. It blocks the sensory nerve endings while sparing the motor nerves at low concentrations. This makes it the ideal drug for post operative pain relief and labour analgesia and therapeutic nerve blocks
Adjuvant Drugs
1) Vasoconstrictors and hyaluronidase
2) Analgesics- They enhance the efficacy of the block and prolong post operative pain relief
3) Some amount of sedation if necessary
Enumeration of Nerve Blocks with their Indications and Brief Details
Scalp Block
1) Suturing of scalp wound
2) Awake craniotomy for brain tumours
of the motor or speech areas
3) Operations around the eye
Retrobulbar and Peribulbar Blocks
1) Most ophthalmic operations
2) Post chamber retinal surgery lasting
upto 3 hours.
Alveolar, Maxillary, Mandibular and Mental Nerve Blocks
Dental and maxillofacial operations
(These blocks are given by the surgeons)
Cervical plexus Blocks
1) Neck operations-Thyroid surgery
2) Surgery on lower occipital part of
scalp
Intercostal Nerve Block
Post operative pain relief following
Thoracotomy
Fracture ribs.
Inguinal Region Block
Inguinal Hernias
Umbilical Hernia
Caudal Block
Hydrocoele operation- an outdoor
procedure
TURP in selected cases
Hypospadiasis repair*
Surgery for undescended testes*
Herniotomy for children*
Perinaeal operations
These are very useful options in children in combination with light general anaesthesia even for prolonged operations. The children are very comfortable and experience minimum stress reaction. The emergence and post operative course is very different from anaesthetizing a child with general anaesthesia alone. For post operative pain they require simple oral analgesics.
Penile Block
Circumcision
Primal Pudendal Nerve Block
Rectal and anal surgery such as piles, fissures, fistula
They are being done increasingly with pudendal nerve block along with local Infiltration.
Upper Limb Blocks
Useful for orthopaedic and other procedures in the upper limb. The common blocks are
1) Brachial Plexus - Interscalene,
Approach
Supraclavicular Approach
Axillary Approach
2) Radial Nerve Block
Median Nerve Block
Ulnar Nerve Block
These nerves can be blocked at
different levels either above or below
the elbow as per surgical
requirements
3) Digital Nerve Blocks for fingers
Lower Limb Blocks
Combined block of the sciatic, femoral, obturator and lateral femoral cutaneous nerve of the thigh can be used to perform a surgical operation on the lower limb. These nerves can be blocked at different levels i.e. in the inguinal regions, political region and at the ankle level.
These blocks are very useful for
Superficial operations such as skin grafting,
Secondary suturing
Diabetic foot*
It must not even be attempted to do an arthroscopy or total knee replacement with a nerve block alone. They may be used as adjuvant or for post operative pain relief.
Regional IV
It is also known as Bier’s block. It is a block of both the upper and lower limbs.
It is given by injecting local anaesthetic into a vein and limiting its spread unto the limb only with the help of a proximal tourniquet. It can be used for surgery lasting more than half hour.
Indications
Soft tissue operations such as ganglion removal, skin grafting
Carpal tunnel syndrome,
Fractures of forearm bones.
Conclusion
As one can see, it is possible to do variety of operations with nerve blocks. However the techniques are not common knowledge. This is because they require practice and technical mastery. With general anaesthesia becoming much safer in the last decade, there is a reluctance on the part of most practicing anaesthesiologist to put the effort to train themselves for these blocks. The good news for them is that with peripheral nerve stimulators now being easily available the techniques are now a lot easier to perform. It is always a good idea to have adequate knowledge and practice of these techniques as in some difficult situations it might be lifesaving for a patient. As day care surgery is becoming a routine practice today the early post operative care of the patient will fall in the domain of the family physician who along with the anaesthesiologist can ensure a comfortable and pain free outcome for the patient.
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