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SPECIAL ARTICLE
Year : 2008  |  Volume : 52  |  Issue : 5  |  Page : 506 Table of Contents     

Continuous Peripheral Nerve Block: the Future of Regional Anaesthesia?


Senior Consultant, Department of Anaesthesiology, Ganga Medical Centre & Hospital, 313, Mettupalayam Road, Coimbatore, India

Date of Acceptance09-Aug-2008
Date of Web Publication19-Mar-2010

Correspondence Address:
J Balavenkatasubramanian
Ganga Medical Centre & Hospital, 313, Mettupalayam Road, Coimbatore
India
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Source of Support: None, Conflict of Interest: None


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Continuous peripheral nerve blocks provide site specific analgesia with least systemic effects. They could be effectively used for intraoperative anaesthesia and as well as for very effective postoperative analgesia. The intro­duction of ultrasound and peripheral nerve stimulators into clinical practice have aided us to place these catheters in close proximity to the neural bundle. The stimulating catheters have further aided us to be more accurate. This article describes the equipment and the technique involved in performing continuous peripheral nerve blocks.

Keywords: Continuous Peripheral Nerve Block(CPNB), Peripheral nerve stimulator, Stimulating and Nonstimulating catheters.


How to cite this article:
Balavenkatasubramanian J. Continuous Peripheral Nerve Block: the Future of Regional Anaesthesia?. Indian J Anaesth 2008;52:506

How to cite this URL:
Balavenkatasubramanian J. Continuous Peripheral Nerve Block: the Future of Regional Anaesthesia?. Indian J Anaesth [serial online] 2008 [cited 2019 Dec 12];52:506. Available from: http://www.ijaweb.org/text.asp?2008/52/5/506/60667


   Introduction Top


The past few years have witnessed a resurgence in the use of regional anaesthetic techniques. Regional anaesthesia per se and as an adjunct to general anaes­thesia in providing balanced anaesthesia has greatly in­fluenced the anaesthetic practice in the past decade. It is becoming increasingly evident that regional anaes­thesia offers immense benefit to the patient in the perioperative period to the extent that it might decrease the perioperative morbidity and influence the overall outcome.

One of the advances in Regional Anaesthesia is the Continuous Peripheral Nerve Blocks (CPNBs) also known as Continuous Perinueral Blocks. Continuous peripheral nerve blocks offer tremendous advantage in the perioperative period. These techniques offer the possibility of prolonging intraoperative anaesthesia while avoiding the risks and side effects of general anaesthe­sia and centrineuraxis block. Continuous perineural blocks are site specific and offer superior analgesia than parenteral opioid analgesia and also are not associated with the possible side effects of opioid analgesia in­cluding nausea, vomiting, sedation, and respiratory depression [1] . The quality of analgesia mimicks that of epi­dural analgesia but it is devoid of ceratin complications associated with epidural anaesthesia like hypotension, urinary retention and pruritus [2] . There is increasing evi­dence to indicate that CPNBs aid in early mobilization, decrease incidence of DVT in the perioperative pe­riod, aid better sleep pattern and decrease the inci­dence of cognitive dysfunction in the perioperative pe­riod. [3]

The chemical sympathectomy produced by CPNBs is ideal after microvascular surgery, reimpla­ntation and free flap procedures. [4] They are also of great use in treating patients with chronic pain syndromes and those requiring palliation for terminal illness. [5] It also helps to provide immediate pain relief in major trauma just after the initial stabilization of the patient. This could be termed as "on arrival block". It is also becoming evident that it not only provides immediate pain relief to the trauma victim but also considerably attenuates the stress response to tissue trauma. The stress response to tissue injury is mediated through neurohormonal, metabolic and immunological responses which in turn result in the release of plethora of chemical mediators like bradykinin, substance P, leukotrienes and interleukin. These chemical mediators in turn produce changes in the end organs and if unabated might lead to systemic inflammatory response syndrome (SIRS) and occasionally even to multiple organ dysfunction syn­drome (MODS). Effective and early analgesia is thought to attenuate this stress response and possibly could prevent the development of SIRS.

The other important factor that is gaining atten­tion is, if acute pain is taken care with adequate analge­sia the possibility of developing chronic pain syndromes as a sequlae of the acute trauma might become less.

Though it became increasingly evident that CPNBs offer great advantage in the management of pain in the perioperative period the main limitation was nonavailability of appropriate equipment. But the past decade has seen a steady growth in the development of catheters and techniques that allow relatively simple, accurate and less invasive catheter placement thus en­suring block effectiveness and decreasing the incidence of secondary block failure.


   Equipments Top


1. Peripheral Nerve Stimulator:

Peripheral electrical nerve stimulation is currently the most common technique for localizing nerves prior to the injection of the local anaesthetic. The equipment used to perform the peripheral nerve block is a periph­eral nerve stimulator

Principle: Depolarising the nerve membrane re­sults in contraction of the effector muscles due to stimu­lation of motor fibres or in paraesthesia due to the pure sensory fibres along the distribution of the nerve. These responses help us to confirm the proximity of the stimu­lating needle or the stimulating catheter to the nerve.

Features: The important features of the nerve stimulator include a constant current output and they are designed to deliver a current output from 0.2mA to 5mA, accurate display of the current delivered, an easy method to control the current intensity, a short pulse width of 100 to 200 microsecond, a disconnect or malfunction indicator. The stimulating frequency could be either 1 or 2 Hz, it has to be remembered while using 1 Hz the needle must be advanced very slowly so to avoid missing the nerve. The polarity of stimulating and returning electrode is very important. The negative electrode or the cathode should be connected to the stimulating electrode which is basically the needle or the stimulating catheter and the anode or the positive electrode to the patient's skin. The polarity of the stimu­lating current is an important aspect of nerve stimula­tion, when the cathode is used as the stimulating elec­trode rather than the anode, significantly less current is required to elicit motor response. In the [Figure 1] the vari­ous parts of the peripheral nerve stimulator have been marked. Many different models of this [Figure 2] periph­eral nerve stimulators are available in the market now.

2. Stimulation needle: The peripheral nerve stimulator is attached to a stimulating needle. The stimu­lating needle is an insulated needle and it is coated with a layer of nonconducting material like polytetra­fluoroethylene or silicon over the entire length of the needle with the exception of the needle tip. Upon stimu­lation the current density focuses on the uncoated tip of the needle. The advantage of these needles is a low threshold current is sufficient to stimulate the target nerve. For continuous blocks the needle gauge must be large enough to allow the passage of a catheter, currently most clinicians use 18 or 19 gauge needles for continuous blocks which aids us to pass a 20 gauge catheter through the needle. Most of these needles have an extension tubing attached to the needle which facili­tates the clinician to aspirate and test for intravascular placement as the needle is advanced towards the nerve and it also helps in injecting the local anaesthetic agents without producing much movement of the needle. One of the common reason for a block failure even after obtaining adequate evoked motor response is the dis­placement of the needle while injecting the local anaes­thetic agent and this is obviated by the addition of this extension tubing.

3. Catheters: The difference between the single shot nerve block and the continuous nerve block is the placement of a catheter. A brief description of the cur­rently available catheters is important. The following systems are available in the catheter through needle system:


   Contiplex A system Top


This was the first commercially available system for CPNB. It involves a cannula over a short bevel needle and an accompanying catheter.


   Contiplex D system Top


This is a subsequent modification of contiplex A [Figure 3] system which includes an integrated wire for nerve stimulation and connection tubing for concurrent aspiration and injection.

Miniset system: This system offers the choice of 21 or 24 gauge needle with either Sporette or Facet tip.


   The Contiplex Tuohy system Top


This system offers the advantage of single opera­tor use. In this apparatus an 18 gauge Tuohy type needle insulated with polytetrafluoroethylene coating along its length with the exception of a pinpoint area at the most distal tip is the hallmark. This Tuohy needle was designed with a Huber tip to facilitate placement of a cath­eter in a direction parallel with the nerve. The system incorporates a 50cm extension tubing which allows for continuous aspiration for blood and injection of local anaesthetic solution by an assistant and which facili­tates an immobile needle technique. The adapter also has a central diaphragm that allows the passage of a catheter through a port separate from where aspiration and injection occurs. This eliminates the need for equip­ment disconnection and minimizes the likelihood of needle movement, catheter misplacement and second­ary block failure. In this system the length of the cath­eter is 100cm and is made of polyamide nylon, it has centimeter gradations until the 20cm and there are three distal orifices with the tip being closed. The catheter is translucent but it has an incorporated tungsten filament which is not highly radiopaque.


   Plexolong system Top


This system also contains an 18 gauge Tuohy tip needle but with a sporette tip, it is radiopaque with styletted catheter. There is a large catheter threading assist device which keeps the catheter in sterile coil.


   Prolong system Top


This system is also a Tuohy tip short bevel tip and a radiopaque catheter without a catheter stylet.


   Stimucath and Polyplex T. Top


These systems have integrated stimulating wire attached to needle and integrated stimulating wire or alligator added to stimulating catheter [Figure 4].

4. Infusion pumps: The continuous catheters once placed successfully in the proximity of the nerve or the plexus are connected to infusion systems which deliver the chosen local anaesthetic agents as a con­tinuous infusion. There are a variety of infusion systems available, including the simple elastomeric pumps, which are easy for use. These elastomeric pumps are dispos­able, deliver a fixed rate and are generally inexpen­sive. The univariate elastomeric pump[Figure 5] that is most suited for CPNB is the one that delivers at a rate of 5ml/hr.Currently multivariate elastomeric pumps are also available and these pumps give the flexibility to alter the rate of infusion. Elastomeric pumps with the option of patient controlled analgesia are also available. Though mechanical, battery-operated pumps of­fer more flexibility of programming and bolus dosing, they tend to be more costly [10] . In developing countries when battery operated mechanical pumps are not avail­able freely elastomeric pumps serve as a good alterna­tives.


   The Continuous Catheter placement techniques Top


The catheter placement techniques that are cur­rently used to place the CPNBs are the nonstimulating catheter technique described by Steele and colleagues [6] and the Stimulating catheter technique described by Sarnoff. [7]


   Nonstimulating catheter technique Top


In the nonstimulating technique an insulated needle is inserted near a nerve with the aid of a peripheral nerve stimulator. Once the needle tip is advanced near the nerve and the desired evoked motor response is obtained, the local anaesthetic agent is injected through the extension tubing that is attached to the needle to expand the perineural space resulting in the produc­tion of the nerve block which is called as the primary block and subsequently the needle is removed and the catheter is passed through the stylet and the local an­aesthetic is injected through this catheter which results in further blocking the nerve called as secondary block. The non-stimulating catheter technique is relatively simple to perform and provides a very reliable primary block. In this technique the only limiting factor is the catheter is placed without confirmation of the tip posi­tion and thus there is the inability to assess the nerve to the catheter tip position, the success rate of the sec­ondary block which is due to the infusion of the local anaesthetic through the catheter may be lower than the primary block . This is infact the disadvantage of the nonstimulating catheters and this problem has been overcome by using a stimulating catheter.


   Stimulating catheter technique Top


In the stimulating catheter technique also known as Sarnoff technique, the nerve stimulator is attached to an insulated 17 to 20 gauge needle eg. Stimucath needle and set to deliver a current of 1-1.5 mA. The needle is advanced until a brisk motor response of the desired muscle group is elicited with a current output of 0.4-0.5 mA. The needle is held steady in the stimu­lating position but no local anaesthetic is injected through the needle. The nerve stimulator is disconnected from the needle and then it is attached to the proximal end of the stimulating catheter. Then the catheter is advanced through the needle to elicit a motor response similar to that elicited by stimulating the needle. Then the cath­eter is advanced beyond the distal end of the needle while maintaining the desired motor response. In case if the motor response disappears or changes to an un­desired quality with advancement of the catheter the catheter is carefully withdrawn inside the shaft of the needle. Now with the catheter in the needle which es­sentially converts stimulation from the catheter to the stimulation through the needle, the needle is carefully manipulated slightly by rotating clockwise and coun­terclockwise or by moving a few millimeters inward or outward, while maintaining the desired evoked motor response. Once the desired stimulation is obtained the catheter is advanced 3 to 5cm along the chosen nerve. With this technique, both the bolus dose and the con­tinuous infusion of local anaesthetic are injected through the catheter. The confirmation of the catheter tip posi­tion logically should provide a lower risk of secondary block failure due to more accurate placement of the catheter.


   Tunneling Top


One of the major concerns while using the CPNB catheters has been the ability to secure these catheters in place without accidental dislodgement. Tunneling is a technique that has been widely used for fixing these catheters. In this technique we do not allow the needle to exit from the same exit wound as the catheter. Here we leave a "skin bridge"between the two. This helps in properly securing the peripheral catheters for a longer time without dislodgement. This also makes catheter removal much safer.


   Pharmacological agents for CPNB Top



   Local anaesthetic agents Top


The long acting local anaesthetic agents are pre­ferred for continuous nerve blocks because they pro­duce a differentiation in sensory and motor blocks and thus it is an important endpoint in providing adequate postoperative analgesia. The drugs of choice are 0.125% to 0.25% bupivacaine, 0.2% ropivacaine and 0.125% levobupivacaine. At these concentrations they provide a postoperative analgesia without impairement of motor function. The infusion rates of these solutions have been found to be effective between the rate of 5­10ml/hr. Though theoretically continuing infusion of a local anaesthetic solution after surgery may be associated with a risk of drug accumulation, pharmacokinetic studies during continuous nerve blocks reported the safety of this technique, with the unbound plasma con­centrations of local anaesthetic remaining well below the threshold levels for systemic central nervous sys­tem toxicity.


   Additives Top


Additive drugs when used alongwith the local anaesthetics prolong the duration of the local anaesthetics and also increase the quality of analgesia. The commonly used additives are epinephrine, sodium bicarbonate, clonidine and opioids.


   Vasoconstrictors Top


Epinephrine in a dose of 5mcg/ml reduces the absorption of local anaesthetics, increasing their con­centration at the intended target nerves increasing the duration and intensity of the block.


   Alkalinisation Top


The alkalinisation of local anaesthetic solutions usually obtained by adding 1mEq of sodium bicarbon­ate to 10ml of lidocaine and mepivacaine reduces the onset time of a nerve block. This however does not happen when sodium bicarbonate is added to bupivacaine and ropivacaine. Though changing the pH may shorten the onset of the block there are not clinically relevant advantages when a continuous periph­eral nerve block is used.


   Clonidine Top


Clonidine added to the local anaesthetic solution improves the duration and the quality of analgesia of the peripheral nerve block. The recommended dose of clonidine is 1mcg/ml and for a continuous block the infusion rate would be 5-7ml/hr.


   Peripheral opioids Top


Opioid agents are known to exert their effects peripherally. Adding small doses of opioids to local anaesthetic solutions for peripheral blocks have resulted in improvement in the onset time, quality and duration of nerve block. Small concentrations of fentany1 1­2mcg/ml, sufentanil 0.1mcg/ml or morphine 0.03mg/ ml have been suggested for continuous infusion. Tramadol has a local anaesthetic effect on peripheral nerves and this could provide potentially a synergistic effect in continuous infusion as an additive to local an­aesthetic agent.


   Common guidelines for CPNB Top


  • The continuous peripheral nerve block is an advanced regional anaesthesia technique, and adequate experience with the single shot technique is necessary to ensure its efficacy and safety.
  • CPNB should be performed in a place where facilitiy for standard monitoring, oxygen source, suctioning, resuscitation equipment and emergency drugs are available.
  • Placement of the catheter should occur under sterile conditions, using, at a minimum, sterile gloves and sterile drapes. A typical block tray is as shown in [Figure 6].
  • After identification and locating the landmarks, site of needle insertion should be infiltrated with local anaesthetic.
  • As needle is advanced towards the target nerve the initial current is set between 1.0-1.5mA and we should constantly watch for the desired evoked motor response (EMR) and once the desired motor response is obtained the current strength is gradually decreased until 0.4mA and if the same EMR persists it is indica­tive that the needle tip is close to the nerve.
  • Local anaesthetic is injected only after making sure that the catheter is not intravascular confirmed by negative aspiration for blood. Before initiating the infu­sion of local anaesthetic, the catheter is first checked for patency, and then the intravascular placement is ruled out by administering a small volume (2-3 mL of 1% lidocaine with epinephrine 1:300,000) and observing for any change in the heart rate.
  • Tunneling is preferred option for securing the catheter without dislodgement.
  • The catheter is secured using a benzoin skin preparation, followed by application of a clear dress­ing. The infusion port should be clearly marked as "con­tinuous block".
  • The patient has to be explained and a consent should be obtained before performing the procedure. The procedure has to be documented in the anaesthe­sia chart.


Sites of Continuous Perineural Block:

The commonly used sites for CPNB include:

  1. Continuous Interscalene Block
  2. Continuous Supraclavicular block
  3. Continuous Infraclavicular Block
  4. ContinuousAxillaryblock
  5. Continuous Femoral Block
  6. Continuous Sciatic Nerve Block
  7. Continuous Popliteal Nerve Block
  8. Continuous Thoracic Paravertebral Block
  9. Continuous Lumbar Paravertebral Block
  10. Continuous Lumbar Plexus Block



   Continuous Interscalene Block Top


Placement of the catheter in the interscalene groove may be one of the more challenging continuous block techniques, although the single-shot interscalene block is one of the easiest to perform and master. This discrepancy is mostly due to the shallow position of the brachial plexus and difficulties in stabilizing the needle during catheter advancement. In addition, there is a difference in stimulating characteristics between the smaller-caliber single shot and larger caliber Tuohy style tip needles. The technique is otherwise similar to the single shot injection with the exception that the needle is inserted at a lower angle so that threading of the catheter becomes easy. This technique provides excel­lent analgesia in patients after shoulder, arm and elbow surgery.


   Procedure Top


The patient is positioned in the same position as in the single-shot technique. The subcutaneous tissues at the projected site of needle insertion are anaesthe­tized with local anaesthetic. The needle is attached to the nerve stimulator (1.0 mA, 2 Hz, 100µsec) and to a syringe with local anaesthetic. With this technique, it is imperative that the palpating hand firmly stabilizes the skin to facilitate needle insertion and insertion of the catheter. A 5-cm block needle is inserted at a slightly caudal angle[Figure 7] and advanced until the brachial plexus twitch is elicited at 0.2 to 0.5mA while paying meticulous attention to the position of the needle, the catheter is inserted some 2-3cm beyond the tip of the needle[Figure 8].


   Continuous Supraclavicular Technique Top


Traditionally the supraclavicular technique has not been considered an optimal choice for placement of catheters. The great mobility of the neck at this loca­tion carries a risk for catheter dislodgement. Tunnelling of the catheter to the infraclavicular level could help to make the catheter more stable; however this does not seem to be the preferred technique at present.


   Continuous Infraclavicular Technique Top


The infraclavicular block[Figure 9] has a particular advantage over the axillary approach for continuous pain management. With the infraclavicular approach, catheter management is simplified by its easy accessi­bility. The catheter is easier to care for and observe and there is less inherent movement than the axillary area, so there is less chance for dislodgement. Patient comfort is greater with an infraclavicular catheter rather than with a dressing in the axillary area.

Different approaches have been utilized success­fully with a continuous infraclavicular technique but there is no overwhelming evidence that favours a particular approach. [8],[9],[10],[11] One could postulate that the lateral sag­ittal approach or the modified Raj approach might of­fer an advantage because the catheter would not be required to make a 90-degree turn from the surface.


   Continuous Axillary Block Top


Continuous axillary brachial plexus block is simi­lar to the single-injection technique, nerve stimulation technique is typically used and catheter is advanced 5­8 cm cephalad into the neurovascular sheath. When a stimulating catheter is used, a non-conducting solution (eg 5% dextrose) [12],[13] can be injected through the cath­eter to dilate the sheath and facilitate insertion of the catheter. However as mentioned earlier fixing the cath­eter is a challenge while using the axillary approach.


   Continuous Femoral Block Top


Continuous femoral block is one of the most com­monly performed lower extremity block.

The primary indication of continuous femoral nerve block is pain management after major femur or knee surgery [14] In addition, when compared with a single dose technique continuous femoral nerve block significantly reduces postoperative opioid consumption in patients after total hip replacement [15] Continuous femoral nerve block provides excellent analgesia in patients with femo­ral shaft or femoral neck fractures [16] Its relative simplic­ity makes it uniquely suitable for analgesia in the emer­gency room and facilitate physical and radiologic ex­aminations as well as manipulations of the fractured fe­mur or hip of a trauma victim.

For knee surgery, continuous femoral block is as effective as continuous lumbar plexus block or con­tinuous epidural analgesia, with fewer risks of compli­cations. Because this technique results in faster post­operative knee rehabilitation than IV PCA with mor­phine and fewer side effects than epidural analgesia, continuous femoral nerve block is probably the anal­gesic technique of choice in patients after total knee arthroplasty. [17]

The choice of local anaesthetic depends on the duration of surgery and whether the catheter is planned for surgical anaesthesia or for postoperative analgesia alone. In our institution, for surgical anaesthesia we use 0.25% Bupivacaine whereas for postopertaive anal­gesia we use a combination of 0.125% bupivacaine with fentanyl, 2µg/ml and the infusion rate ranging be­tween 5-7ml/h.


   Procedure Top


The patient lies in supine position. The ipsilateral extremity is abducted 10 - 20 degrees. The site of needle insertion is 1cm below the inguinal ligament and 1 cm lateral to the femoral artery. The needle is intro­duced at an angle of 45 degrees to the skin [Figure 10]. The more distal needle insertion site prevents the pos­sibility of insertion of the needle into the pelvis and al­lows insertion of the needle more tangentially and thus facilitates insertion of the catheter with ease. After pas­sage through the fascia lata, the needle is advanced to elicit a patellar twitch using a current output between 0.2 - 0.5 mA (0.1 msec). After obtaining this response the catheter is inserted 5-10 cm beyond the tip of the needle or introducer. It is secured in place with a stitch tunneling and/or a dressing.


   Continuous Sciatic block Top


This technique can be used for surgery and post­operative pain management in patients undergoing a wide variety of lower leg, foot, and ankle surgeries. Perhaps the single most important indication for use of this block is for amputation of the lower extremity.


   Procedure Top


The continuous sciatic block technique is similar to the single-shot technique. Proper positioning at the outset and maintenance of the position during the con­tinuous sciatic nerve block are crucially important to allow for precise catheter placement. A slight forward pelvic tilt prevents the "sag" of the soft tissues in the gluteal area and significantly facilitates block placement. [18] With the patient in the lateral decubitus position and a slight forward pelvic tilt, the landmarks are identified and marked with the pen. After a thorough skin clean­ing with antiseptic solution, the skin at the needle inser­tion site is infiltrated with local anaesthetic. A 10-cm long continuous block needle is connected to the nerve stimulator (1.5mA) and inserted at an angle perpen­dicular to the skin sphere. The opening of the needle should face distally (pointing toward the patient's foot) to facilitate catheter insertion. The initial intensity of the stimulating current should be 1.0-1.5 mA. As the needle is advanced, the first twitches obtained are from the gluteus muscle. Deeper needle advancement results in stimulation of the sciatic nerve. The best results are obtained when we get the inversion and not eversion as the evoked motor response. After obtaining the appropriate twitches, manipulate the needle until the desired response is seen or felt using a current of 0.2­0.5mA. At this point, a bolus of local anaesthetic is injected (20 mL) after negative aspiration for blood. This is followed by insertion of the catheter 5-10cm catheter beyond the needle tip. One of the commonest concern while using sciatic catheters has been the acci­dental dislodgement of the catheter.


   Continuous Popliteal Block Top


This technique can be used for surgery and post­operative pain management in patients undergoing a wide variety of lower leg, foot, and ankle surgeries.


   Procedure Top


The continuous popliteal block technique is simi­lar to the single-shot technique. With the patient in the prone position, the skin is infiltrated with local anaes­thetic using a 25-gauge needle at the injection site which is 7cm above the popliteal fossa crease and between the tendons of biceps femoris and semitendinosus muscles. A 5 to 10cm needle connected to the nerve stimulator (1.5mA current) is inserted at the midpoint between the tendons of the biceps femoris and semi­tendinosus muscles. [19] The block needle is advanced slowly with a slight cranial direction while seeking a plantar or dorsiflexion of the foot or toes. After obtain­ing appropriate motor response, the needle is manipulated until the desired response is seen or felt using a current of approximately 0.5mA.The catheter should be advanced some 5cm beyond the needle tip.

Continuous Popliteal Block through the lateral approach.

With the patient in the supine position, the skin is infiltrated with local anaesthetic at the injection site 8cm above the popliteal fossa crease and in the groove be­tween the biceps femoris and vastus lateralis muscle using a 25-gauge needle [20] . A 10-cm Tuohy-style tip needle for continuous nerve block is connected to the nerve stimulator (at 1.5mA current intensity) and inserted to contact the femur [Figure 11]. Once the femur is contacted the needle is withdrawn to the skin and redi­rected in a slight cranial and posterior direction relative to the plane in which the femur was contacted (usually 30 degrees to the horizontal plane).

The needle is advanced slowly while seeking a plantar flexion or dorsiflexion of the foot or toes. After obtaining appropriate twitches, the needle is manipu­lated until the desired response is seen or felt using a current of 0.4mA. The catheter should be advanced some 5-7cm beyond the tip of the needle and secured and fixed[Figure 12].


   Conclusion Top


The advances in the techniques and technologies pertaining to regional anaesthesia offer an entirely a new spectrum of anaesthesia delivery system to the patients. Site specific analgesia would be probably the most pre­ferred anaesthetic technique of the next decade. The development of stimulating catheters has significantly improved the precision with which these catheters are placed near the peripheral nerves and plexuses and thus increasing the success rate. It offers a promise for the future as these continuous perineural catheters might greatly influence the perioperative outcome.

 
   References Top

1.Smith BE, Fischer HB, Scott PV. Continuous sciatic nerve block. Anaesthesia 1984;39:155-57.  Back to cited text no. 1      
2.Serpell MG, Millar FA, Thompson MF. Comparison of lumbar plexus block versus conventional opioid analgesia after total knee replacement. Anaesthesia 1991;46:275-77.  Back to cited text no. 2      
3.Zaric D, Boysen K, Christiansen J, et al. Continuous popliteal sciatic nerve block for outpatient foot surgery­ a randomised controlled trial.Acta Anaesthesiol Scand 2004;48:337-341.  Back to cited text no. 3      
4.Van den berg B, Berger A, Van den berg E, et al. Con­tinuous plexus anaesthesia to improve circulation in peripheral microvascular interventions. handchir mikrochir plast hir 1983;15:101-104.  Back to cited text no. 4      
5.Fischer HB. Peters TM, Fleming IM, Else TA:Peripheral nerve catheterisation in the management of terminal cancer pain. Reg Anaesthesia and pain medicine 1996;5:482-485.  Back to cited text no. 5      
6.Steele SM, Klein SM, et al. A new continuous catheter delivery system. Anaesth Analgesia 1998;87:28.  Back to cited text no. 6      
7.Boezaart AP, de Beer JF. Accurate placement of catheter for selective continuous interscalene brachial plexus nerve block. World congress of Anaesthesiologists, 1996,Sydney, Australia, Abstract number V 14.  Back to cited text no. 7      
8.Macaire P, Gaertner E, Capdevila X. Continuous post operative regional analgesia at home. Minerva Anestesiol 2001; 67:109-116.  Back to cited text no. 8      
9.Mehrkens HH, Geiger PK. Continuous brachial plexus blockade via the vertical infraclavicular approach. Anaesthesia 1998;53:19-20.  Back to cited text no. 9      
10.Kapral S, Jandrasits O, Schabernig C, et al. Lateral infra­clavicular plexus block vs axilllary block for hand and forearm and forearm surgery. Acta Anaesthesiol Scand 1999;43:1047 - 1052.  Back to cited text no. 10      
11.Klaastad O, Smith H-J, Smedby O, et al. Response to letter to editor Anesth Analg 2004;99:950 - 951.  Back to cited text no. 11      
12.Tsui BC, Wagner A, Finucane B:Electrophysiologic ef­fect of injectates on peripheral nerve stimulation. Reg Anesth Pain Med 2004;29:189-193.  Back to cited text no. 12      
13.Bogoch ER, Henke M, Mackenzie T, et al. Lumbar paravertebral nerve block in the management of pain after total hip and knee arthroplasty: A randomized con­trolled clinical trial. J Arthroplasty 2002;17: 398 - 4036.  Back to cited text no. 13      
14.Anker-Moller E, Spansberg N, Dahl J, et al. Continuous blockade of the lumbar plexus after knee surgery: A com­parison of the plasma concentrations and analgesic ef­fect of bupivacaine 0.250% and 0.125%. Acta Anaesthesiol Scand 1990;34:468-472.  Back to cited text no. 14      
15.Singelyn FJ, Ebongo F, Symens B, et al. Influence of the analgesic technique on postoperative rehabilitation af­ter total hip replacement. Reg Anesth Pain Med 2001;26:39.  Back to cited text no. 15      
16.Capdevila X, Biboulet P, Bouregba M, et al. Bilateral continuous 3-in-1 nerve blockade for postoperative pain relief after bilateral femoral shaft surgery. J Clin Anesth 1998;10:606-609.  Back to cited text no. 16      
17.Serpell M, Millar F, Thomson M. Comparison of lumbar plexus block versus conventional opioid analgesia af­ter total knee replacement. Anaesthesia 1991;46:275-277.  Back to cited text no. 17      
18.Di Benedetto P. Casati A, Bertini L.Continuous subgluteus sciatic nerve block after orthopedic foot and ankle surgery : comparison of two infusion techniques. Reg Anesth Pain Med 2002; 27:168-172.  Back to cited text no. 18      
19.Ilfeld BM, Morey TE, Wang DR, Enneking F K. Continu­ous popliteal sciatic nerve block for post operative pain control at home : A randomized double blinded, placebo­controlled study Anesthesiology 2002;97:959- 965.  Back to cited text no. 19      
20.Chelly JE, Greger J, Casati A: Continuous lateral sciatic blocks for acute postoperative pain management after major ankle and foot surgery. Foot Ankle Int 2002;23:749- 752.  Back to cited text no. 20      


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12]



 

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  In this article
    Abstract
    Introduction
    Equipments
    The Continuous C...
    Pharmacological ...
    Common guideline...
    Contiplex A system
    Contiplex D system
    The Contiplex Tu...
    Plexolong system
    Prolong system
    Stimucath and Po...
    Nonstimulating c...
    Stimulating cath...
    Tunneling
    Local anaestheti...
    Additives
    Vasoconstrictors
    Alkalinisation
    Clonidine
    Peripheral opioids
    Continuous Inter...
    Procedure
    Continuous Supra...
    Continuous Infra...
    Continuous Axill...
    Continuous Femor...
    Procedure
    Continuous Sciat...
    Procedure
    Continuous Popli...
    Procedure
    Conclusion
    References
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