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Year : 2012  |  Volume : 6  |  Issue : 3  |  Page : 315-317

An improvised indigenous technique for nerve stimulation-assisted peripheral nerve blocks

Department of Anesthesiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Correspondence Address:
Anuj Jain
Department of Anesthesiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1658-354X.101241

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Date of Web Publication21-Sep-2012


Regional anesthesia is one of the most satisfying expertise in anesthesia. Nerve stimulation guided peripheral nerve blocks greatly enhance the success rate of block. Often the nerve stimulation needle becomes a limiting factor due to cost and unavailablity. We have proposed a simple innovation to create a nerve stimulation needle at the point of care that would overcome the limitation associated with commercially available needle for nerve stimulation .This innovation may prove instrumental in training of anesthesia residents at no extracost to the patient.

Keywords: Nerve stimulation needle, peripheral nerve blocks, regional anesthesia

How to cite this article:
Jain A, Singh S. An improvised indigenous technique for nerve stimulation-assisted peripheral nerve blocks. Saudi J Anaesth 2012;6:315-7

How to cite this URL:
Jain A, Singh S. An improvised indigenous technique for nerve stimulation-assisted peripheral nerve blocks. Saudi J Anaesth [serial online] 2012 [cited 2020 Sep 20];6:315-7. Available from:

  Introduction Top

Regional anesthesia (RA) is one of the most challenging and satisfying modalities in the branch of anesthesia. Somehow, the scope of RA has been limited to central neuraxial blockade, with most of the centers not practising peripheral nerve blocks (PNBs) due to some reason or the other. The chief reason for deferring PNBs is the high failure rates associated with the procedure.

Efforts are on to revive the modality of PNBs by using guided techniques like nerve stimulation-guided (NSG) and ultra sonography (USG)-guided nerve blocks and, at times, combining both these techniques. Although the guided nerve block techniques increase the success rate many folds, there are drawbacks associated with guided techniques as well. USG is most of the times not available owing to its cost and, if available, the learning curve with USG is long. NSG blocks have different problems. The stimulator needle becomes the limiting factor as it is costly and hence usually not available in hospital stocks. Because of its higher cost per procedure and usual unavailability of nerve stimulator needle, NSG blocks are seldom performed. Although the problem associated with USG-guided PNBs cannot be resolved without adequate funds, we suggest a unique innovation as far as NSG blocks are concerned. The aim of this innovation is to increase the expertise among the anesthesia residents in placing PNBs, which would drastically improve the efficiency of day care facilities in developing countries.

  Description Top

A nerve stimulator is a machine that produces a DC output that can be regulated. It has two electrodes, i.e. one positive electrode and one negative electrode. The negative electrode is connected to the nerve stimulator needle and the positive electrode is attached to a skin electrode placed along the route of the nerve to be blocked. When the needle is inserted into the skin and as it approaches the proximity of the nerve, muscle twitches are seen, as the current starts to flow along the nerve from the active electrode to the passive electrode along the nerve, thereby stimulating the nerve. The intensity of current is gradually reduced to a target of 0.3-0.4 mA, at which muscle twitches are visible. This indicates that the tip of the needle is very close to the nerve and that the local anesthetic solution can be injected.

  Improvised Needle Top

Our improvised needle is a modified 20 swg intravenous (iv) cannula. An iv cannula has four parts, i.e. a metallic stylet with a luer chamber, a polyvinyl chloride cannula, a flashback chamber and a luer lock cap [Figure 1]. The iv cannulae can be converted into a nerve stimulator needle in four simple steps [Figure 2].
Figure 1: Diagram showing various parts of an intravenous cannulae

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Figure 2: Flashback chamber of an intravenous cannulae

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Step 1: The diaphragm of the flashback chamber is perforated using a 14G hypodermic needle.
Step 2: The negative electrode is inserted through the perforated diaphragm of the flash back chamber [Figure 3].
Figure 3: Negative electrode of the nerve stimulator inserted through the flashback chamber

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Step 3: The flashback chamber is attached to the luer chamber [Figure 4].
Figure 4: Final assembly of the nerve stimulator needle

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Step 4: The nerve stimulator electrode is adjusted so that it touches the stylet in the luer chamber.

In this way, the improvised nerve stimulator needle is ready to be used. This improvised needle can be used to locate the nerve in the usual manner as described earlier. Once the nerve has been localised, the stylet can be removed to leave the catheter in situ for drug injection or the flashback chamber detached and injection of drug made through the stylet.

We have used this improvised needle in placing upper extremity blocks and lower extremity blocks in normal-built patients [Table 1] with almost 100% success. This needle's length may not be adequate in placing lower extremity blocks in obese patients.
Table 1: The average depth from the skin at which the nerve is encountered

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Therefore, a procedure as simple as making a hole in the flash back chamber of an iv cannula can help popularize the technique of nerve-stimulated guided PNBs at no extra cost of the costly nerve stimulator needle. The cost factor and availability of nerve stimulator needles may not be a limiting factor in popularising PNBs in the developed countries, but they definitely matter for the developing countries.


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1]

This article has been cited by
1 A superior indigenous technique for nerve stimulation-assisted peripheral nerve blocks
Shetti, A.
Saudi Journal of Anaesthesia. 2012; 6(4): 437-438


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