AUTHOR AND EDITOR INFORMATION

Section 1 of 8  

• Authors and Editors
• Introduction
• Neuraxial Analgesia
• Peripheral Nerve Blocks
• Wound Infiltration
• Analgesic Options for Specific Surgeries
• Practical Aspects
• References

INTRODUCTION

Section 2 of 8  

• Authors and Editors
• Introduction
• Neuraxial Analgesia
• Peripheral Nerve Blocks
• Wound Infiltration
• Analgesic Options for Specific Surgeries
• Practical Aspects
• References

In many centers, regional anesthesia techniques are used extensively to allow the performance of orthopedic procedures. The intraoperative use of regional anesthesia has many advantages, including the following:

Advantages of intraoperative use of regional anesthesia

• Reduces blood loss: In total hip arthroplasty (THA), studies have demonstrated that both spinal and epidural anesthesia tend to have approximately a 30% reduction in intraoperative blood loss compared with general anesthesia due to lower arterial and venous pressures.


• Reduces rates of deep venous thrombosis (DVT): Epidural and spinal anesthesia both reduce DVT risk by improving blood flow through the legs secondary to sympathectomy-induced vasodilatation; both anesthesia methods may also reduce perioperative hypercoagulability that occurs as a result of the surgical stress response.


• Avoids common adverse effects of general anesthesia: Such adverse effects include nausea, sore throat, alteration of mental status, and cognitive dysfunction.


• Allows patient involvement: Some patients enjoy the ability to watch knee arthroscopic procedures on the video monitor.


• Improves pain control: Regional techniques can block or reduce pain anywhere from several hours to several days, depending on the technique that is used. Preemptive pain management may reduce subsequent pain in the days to weeks following surgery. Greater pain control has the potential to allow for earlier hospital discharge and may improve the patient's ability to tolerate physical therapy.

Various regional analgesia techniques exist that can be used to promote postoperative pain relief. These methods can be categorized into neuraxial local analgesics and narcotics, peripheral nerve blocks, and wound infiltration.

NEURAXIAL ANALGESIA

Section 3 of 8  

• Authors and Editors
• Introduction
• Neuraxial Analgesia
• Peripheral Nerve Blocks
• Wound Infiltration
• Analgesic Options for Specific Surgeries
• Practical Aspects
• References

Intrathecal analgesia

Intrathecal (IT) narcotics can offer effective postoperative analgesia. These agents bind with opioid receptor sites in the dorsal horn of the spinal cord, resulting in modulation of pain signals at the spinal cord level. IT narcotics can be administered as an adjunct to general anesthesia (eg, for scoliosis surgery), or they can be mixed with local anesthetics and administered during spinal anesthesia (eg, for total hip arthroplasty). For IT morphine, the onset of analgesia is 30-60 minutes, and the duration of analgesia is 18-24 hours, depending on the dose that is used. 

Adverse effects of IT narcotics include nausea, pruritus, urinary retention, and respiratory depression. Respiratory depression from IT morphine peaks at approximately 7-9 hours after surgery and is dose dependent. The incidence of respiratory depression in 1 retrospective study was 0.36%,¹ but the incidence is probably lower now because smaller doses are currently used. The postinjection incidence of nausea and vomiting for IT morphine is approximately 20% and peaks at approximately 4 hours. Pruritus occurs in approximately 40% of patients, but severe cases (requiring treatment) occur in about 9%.² The incidence of urinary retention is difficult to estimate because many patients receive prophylactic catheterization, which appears to be required in 10-40% of surgical patients.²

The advantages of IT analgesia, especially if spinal anesthesia is already planned, include its simplicity, lack of need for catheter care or pumps, low cost, and easy supplementation with low-dose patient-controlled analgesia (PCA) narcotics as needed. The main disadvantages of this technique are limited duration of action (in comparison to catheter techniques) and the adverse effects discussed above. When higher doses of IT narcotics are used, frequent monitoring of respirations is mandated.

Contraindications to use of IT anesthesia include heparinization or other coagulopathy, local or systemic infection, and morphine allergy.

Dosing is as follows:

• Total hip arthroplasty – Morphine 100-200 mcg


• Total knee arthroplasty – Morphine 200-300 mcg


• Spine fusion, scoliosis surgery – Morphine 300 mcg or 3-5 mcg/kg

Epidural analgesia

Epidural analgesia is accomplished by means of epidural narcotics, local anesthetics, or their combination. Narcotics can be administered by bolus or infusion. Adverse effects are the same as those of IT narcotics (see Intrathecal analgesia, above). Epidural local anesthetics, typically diluted solutions of bupivacaine or ropivacaine, are administered by infusion. Adverse effects of epidural local anesthetics include urinary retention, motor block, and a sympathectomy-induced decrease in blood pressure. Epidural local anesthetics and narcotics are frequently combined in lower dosages to decrease the risk of each drug's associated adverse effects.

The duration of epidural infusion depends on several factors. Epidural catheters must be removed before the advent of significant anticoagulation from heparin, low-molecular-weight heparins (LMWH), or Coumadin (warfarin sodium for injection; Bristol-Myers Squibb Co, Princeton, NJ). The authors generally remove epidural catheters by 72 hours to reduce the risk bacterial colonization at the catheter site.

A wide variety of dosing regimens for regional anesthesia are in use. Narcotic and local anesthetic drugs can be combined in the same infusion and run at a lower rate. Intravenous (IV) PCA narcotics can be administered as an adjunct to local anesthetic infusions.

Typical epidural infusions include the following:

• Morphine (0.01%) – 5-10 mL/h


• Fentanyl (0.001%) – 5-10 mL/h


• Hydromorphone (0.005%) – 5-10 mL/h


• Bupivacaine (0.05-0.1%) – 5-10 mL/h


• Ropivacaine (0.1%) – 5-10 mL/h

Treatment of epidural or IT narcotic adverse effects is as follows:

• Urinary retention – Urinary catheterization


• Pruritus – Diphenhydramine (Benadryl; McNeil-PPC, Inc, Fort Washington, Pa) 25-50 mg IV or intramuscular (IM) route, or naloxone 0.1-0.2 mg IV or subcutaneous (SC) route


• Nausea/vomiting – Metoclopramide (Reglan; Baxter Healthcare Corp, Deerfield, Ill) 10 mg IV; ondansetron (Zofran; GlaxoSmithKline, Research Triangle Park, NC) 4 mg IV; droperidol 0.625-1.25 mg IV; or naloxone 0.1-0.2 mg IV/SC


• Respiratory depression – Naloxone 0.2-0.4 mg IV

As an alternative to boluses, naloxone can be administered by infusion at 0.2-0.3 mg/h.

Neuraxial blocks and anticoagulation

The American Society of Regional Anesthesia and Pain Medicine has made the following recommendations regarding neuraxial blocks.³ When any anticoagulant is administered perioperatively in a patient with a neuraxial catheter in place, close neurologic monitoring of the lower extremities is mandated as follows:

• Antiplatelet drugs: When administered alone, drugs such as aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) do not appear to increase the risk of neuraxial hematomas. However, they may increase such a risk when administered concurrently with other anticoagulants.


• Heparin
  • Preoperative minidose SC heparin is generally not considered a contraindication to neuraxial block, but administration may be better delayed until after the block.
  
  
  • Intraoperative IV heparin, as used in vascular surgery, is best delayed until at least 1 hour after neuraxial block placement.
  
  
  • When patients are on postoperative heparin infusions, before catheter removal, heparin should be windowed for 2-4 hours, and coagulation/clotting status (as tested by activated partial thromboplastin time [aPTT] or activated coagulation/clotting time [ACT]) should be normalized.


• Low-molecular-weight heparins: Neuraxial blocks should not be performed within 12-24 hours of LMWH administration. Postoperative administration of LMWH should be started no earlier than 24 hours after surgery. After the removal of an indwelling catheter, LMWH should be started at least 2 hours later; when a patient has an indwelling catheter in place, LMWH administration should be performed with extreme caution. Ideally, catheters should be removed 24 hours after the last LMWH dose.


• Warfarin: Patients on long-term warfarin should discontinue it and have their normalized prothrombin time (PT) or international normalized ratio (INR) measured before neuraxial block. When patients receive their first dose of warfarin more than 24 hours before surgery or 2 doses before surgery, the PT and INR should be checked before the initiation of neuraxial block.

  If catheters are left in place and the initial warfarin dose was more than 36 hours ago, the PT and INR should be assessed before catheter removal. If the INR is less than 1.5, the catheters can be safely removed. If patients become significantly anticoagulated (INR >3), warfarin should not be administered, and the PT and INR should be allowed to become more normalized before removal of the catheter. The optimal safe level of anticoagulation at the time of catheter removal is unclear.

PERIPHERAL NERVE BLOCKS

Section 4 of 8  

• Authors and Editors
• Introduction
• Neuraxial Analgesia
• Peripheral Nerve Blocks
• Wound Infiltration
• Analgesic Options for Specific Surgeries
• Practical Aspects
• References

Peripheral nerve blocks can provide significant pain relief. Nerve blocks can either be combined with general anesthesia or used as the sole anesthetic. Long-acting local anesthetics, such as bupivacaine or ropivacaine, provide a nerve-block duration of approximately 12 hours. However, longer duration can be achieved by the perineural placement of catheters, which are then infused continuously, or boluses are given as needed.

Serious adverse effects of peripheral nerve blocks are rare. Adverse effects can be categorized as due to either local anesthetic toxicity, complications of needle placement, or spillover of local anesthetic to the surrounding neural structures. Local anesthetic toxicity can occur because of unplanned intravascular injection or slow absorption from the injection site. This can manifest as reactions ranging from tinnitus and dizziness to convulsions and cardiac arrest. Complications of needle placement can include hematomas, dysesthesias (0.2%),⁴ and other problems related to the specific nerve block. Spillover adverse effects are manifested mainly in interscalene and supraclavicular blocks.

Peripheral nerve blocks have the advantages of no sympathectomy-induced decrease in blood pressure and no narcotic-related adverse effects such as urinary retention, nausea, or itching. However, some degree of motor block is observed with the sensory block. This result may limit the usefulness of some peripheral blocks in certain situations. For example, prolonged femoral blocks are a good choice for pain control in anterior cruciate ligament (ACL) reconstructions, but they are not a good choice in knee arthroscopy because the quadriceps motor block would prevent safe ambulation.

Successful use of nerve blocks depends not only on  clinical knowledge of the site of incision innervation but also on knowledge of the innervation for the underlying bone and muscular tissue.

Brachial plexus blocks

The brachial plexus can be anesthetized at sites above the clavicle (interscalene and supraclavicular approaches) or below the clavicle (infraclavicular and axillary approaches). The interscalene approach is used for shoulder and upper arm surgery because the roots of both the brachial and cervical plexuses are anesthetized. This is generally not a good approach for lower arm or hand surgery because the C8 and T1 nerve roots are frequently inadequately anesthetized. The supraclavicular approach can result in good block of the arm and hand. The infraclavicular or axillary approaches are used for surgery of the elbow, lower arm, and hand.

Interscalene and supraclavicular blocks, although safely performed in most patients, have more adverse effects and risks associated with them. Phrenic nerve dysfunction occurs in 100% of interscalene blocks⁵ and 25-50% of supraclavicular blocks.⁶ Thus, these blocks may not be well tolerated in patients with preexisting respiratory compromise. Case reports exist of epidural⁷ or IT injections⁸ with interscalene blocks. Pneumothorax has been reported to occur in less than 1-5% of supraclavicular blocks and probably depends on the technique used. Horner syndrome (sympathetic chain) and hoarseness (recurrent laryngeal nerve) commonly occur from spread of anesthetic to surrounding nerves.

For hand surgeries, more distal blocks can also be performed to provide analgesia. Block of the radial, median, and ulnar nerves at the wrist or block of the digital nerves of the fingers can be performed.

Leg blocks

The knee joint is innervated by the femoral (anteriorly), sciatic (posteriorly), obturator (medially), and lateral femoral cutaneous nerves (laterally). Femoral nerve blocks are frequently used for analgesia after knee surgery; however, the degree of analgesia depends on the amount of surgical trespass into other nerve distributions. Thus, patients undergoing arthroscopic ACL and patellar surgery obtain excellent pain relief after femoral block, whereas patients undergoing knee replacement surgery frequently have severe posterior pain of sciatic origin. Unless the knee is properly braced, weightbearing and ambulation may need to be restricted until quadriceps function recovers in patients with femoral nerve blocks.

Sciatic nerve or popliteal fossa blocks are performed to provide analgesia after foot surgery. The popliteal fossa block is a block of the sciatic nerve in the popliteal fossa in the vicinity of the sciatic nerve's division into the tibial and common peroneal nerves. The advantage of a popliteal fossa block over standard sciatic blocks is that hamstring function is maintained. A saphenous block can be added if the site of surgery includes the medial malleolus.

For some foot or toe surgeries, more distal nerve blocks can also be performed to provide analgesia. Blocks of the deep peroneal, superficial peroneal, tibial, sural, and saphenous nerves can be performed at the ankle level, or block of the digital nerves of the toes can be used.

WOUND INFILTRATION

Section 5 of 8  

• Authors and Editors
• Introduction
• Neuraxial Analgesia
• Peripheral Nerve Blocks
• Wound Infiltration
• Analgesic Options for Specific Surgeries
• Practical Aspects
• References

The infiltration of wounds with local anesthetics not only provides analgesia but also appears to reduce the local inflammatory response to trauma or surgery. Thus, local infiltration may help reduce the upregulation of peripheral nociceptors that manifests as hypersensitivity to a stimulus.

Local anesthetic can be administered in skin incision sites, intra-articularly (knee and shoulder), or on bone wounds (iliac crest graft sites). Bupivacaine or ropivacaine provides approximately 6 hours of analgesia. Alternatively, catheters can be placed at these locations, so that either local anesthetic can be infused continuously or boluses can be administered with patient-controlled pumps. With the advent of disposable infusion pumps, home discharge with a catheter and pump in place is now possible. Details regarding patient selection and the safety of this practice are being investigated.

Peripherally located opioid receptors have been discovered in animals. Animal studies suggest that intra-articular inflammation induces the development of synovial opioid binding sites. In addition, intra-articular opioid administration appears to have an anti-inflammatory effect. Based on these observations, intra-articular narcotics are administered in knee and shoulder surgery.

The effect of intra-articular morphine in knee arthroscopy has been examined in multiple studies. A recent meta-analysis concluded that a mild analgesic effect of intra-articular morphine is observed,⁹ but a systemic effect cannot be excluded completely. Whether a dose-response effect is observed and what the optimal dose is are still in question. Morphine doses of 1-5 mg have been used.

Regarding shoulder surgery, in a study of patients undergoing open rotator cuff repairs,¹⁰ patients receiving a combination of 1 mg of morphine with 20 mL of 0.25% bupivacaine had better postoperative pain relief than those patients receiving bupivacaine alone. In another interesting study of patients with cervical diskectomy, 5 mg of morphine infiltrated into the iliac crest donor site produced better short-term analgesia and resulted in less chronic pain in the months after surgery.

ANALGESIC OPTIONS FOR SPECIFIC SURGERIES

Section 6 of 8  

• Authors and Editors
• Introduction
• Neuraxial Analgesia
• Peripheral Nerve Blocks
• Wound Infiltration
• Analgesic Options for Specific Surgeries
• Practical Aspects
• References

For any specific surgery type, several regional anesthetic pain management options may be present. The choices may include the above-mentioned wound infiltration, neuraxial or peripheral nerve block techniques, or a combination of techniques. Analgesic techniques are selected based on the surgical trauma, goals for physical therapy, expected length of patients' hospital stay, and avoidance of adverse effects.

Spine surgery

IT morphine has been used as an adjunct in complex spine surgery such as scoliosis surgery.

Iliac crest harvest site infiltration with morphine and local anesthetic is an option.

Shoulder/arm/hand surgery

Shoulder surgery can be performed under interscalene nerve block or a combination of general and interscalene block. Complete pain relief can be achieved (for the duration of the block) unless the incision extends close to the axilla. Interscalene catheters can be placed and infused for prolonged analgesia.

Other pain management options include subacromial or intra-articular morphine and local anesthetic.

Interscalene, axillary, and infraclavicular catheters can be placed for prolonged pain relief or arm surgery. Besides pain relief, the arm sympathectomy may be of value in certain operations involving vascular repairs.

Hip surgery

IT morphine is very effective for pain control after hip surgery in the first 12-24 hours.

Epidural local anesthetic and narcotic can be infused. The duration of the infusion is limited by perioperative anticoagulation for DVT prophylaxis and by the need to terminate motor nerve block so that physical therapy can be performed. Thus, at the authors' institution, epidural catheters are typically removed on the morning of postoperative day 1.

Knee arthroplasty

IT morphine can be used for pain control after knee arthroplasty in the first 12-24 hours.

As with hip surgery, epidural local anesthetic and narcotic can be infused, and the infusion duration is limited by perioperative anticoagulation for DVT prophylaxis and by the need to terminate motor nerve block for the performance of physical therapy. At the authors' institution, epidural catheters are typically removed on postoperative day 1.

Femoral and sciatic nerve blocks can be used. Femoral blocks alone are usually not adequate because of posterior capsular pain that is of sciatic innervation origin. Continuous femoral nerve block with single-shot sciatic nerve block has been described to be effective.

Knee arthroscopic procedures

Epidural anesthesia is an effective technique for patients undergoing arthroscopic ACL repair. However, because this procedure has evolved to an outpatient or 23-hour stay procedure, epidural adverse effects such as urinary retention and motor block make epidural anesthesia an unsuitable technique for postoperative use. Instead, femoral block is frequently used and provides very effective pain relief. At the authors' institution, femoral nerve block is typically used with intra-articular bupivacaine/morphine.

For patient pain control in arthroscopy/meniscectomy, intra-articular local anesthetic and morphine are used routinely. Long-acting femoral blocks are avoided so that patient ambulation is not impeded.

Foot

Foot and ankle pain can be controlled with a popliteal fossa block. The saphenous nerve may also need to be blocked if the surgical incision is on the medial aspect of the foot or ankle.

PRACTICAL ASPECTS

Section 7 of 8  

• Authors and Editors
• Introduction
• Neuraxial Analgesia
• Peripheral Nerve Blocks
• Wound Infiltration
• Analgesic Options for Specific Surgeries
• Practical Aspects
• References

Peripheral nerve blocks can provide excellent pain relief but have the problem of limited duration. An example of this scenario is a rotator cuff operation performed with a bupivacaine interscalene block. The sudden return of pain 12-18 hours after the bupivacaine interscalene block can be very distressing to the patient and result in the need for large doses of narcotics to control the patient's pain. Strategies to manage such a need include the following:

Perioperative narcotics

It is a good strategy for the patient to receive a dose of narcotic before the expected time of nerve-block resolution. The authors typically have patient narcotic IV PCA pumps already set up and in use before the removal of epidural catheters. OxyContin (oxycodone HCl controlled-release tablets; Purdue Pharma LP, Stamford, Conn) has been demonstrated to be an effective analgesic for orthopedic procedures. For example, the first dose of OxyContin can be administered 10-12 hours after the placement of a bupivacaine interscalene nerve block for shoulder surgery. As-needed narcotics should always be available for pain control once the nerve block has terminated.

Perioperative nonsteroidal anti-inflammatory drugs

NSAIDs can be used as a supplement to narcotics. Intravenous ketorolac (Toradol; Roche Laboratories Inc, Nutley, NJ) is a very effective pain reliever of orthopedic pain. While a nerve block is in effect, ketorolac 15-30 mg IV every 6 hours can be administered as a background analgesic without respiratory depressant effects. Concerns about the use of NSAIDs include platelet dysfunction, renal dysfunction, gastric ulceration (especially in patients receiving oral anticoagulants), and potentially decreased bone growth and healing, which might have an impact on fusion success rates following spinal surgery or implant osteointegration following cementless total joint replacement. Another alternative is the oral cyclooxygenase-2 (COX-2)–inhibitor drug celecoxib (Celebrex; Pfizer Inc, New York, NY). Celecoxib can be administered preoperativly as a 200-400 mg load, then the dosing regimen can be continued with a dose of 200 mg orally once a day.The advantage of this drug is that it does not  cause significant platelet dysfunction. However, there is controversy regarding the use of celecoxib in patients with known cardiac disease or with risk factors for cardiac disease.

Catheter techniques

Catheter techniques can be used to prolong the duration of peripheral nerve blocks; both continuous infusion and PCA techniques have been used. Nerve blocks that are amenable to catheter placement include interscalene, infraclavicular, axillary, femoral, and popliteal fossa. Intrabursal, intra-articular, and intrawound catheter placement are also possible. The local anesthetic chosen for infusion is typically either bupivacaine (0.125-0.25%) or ropivacaine (0.1-0.2%). Potential problems include technical failure, catheter dislodgment, and bacterial colonization of the catheter site. Disposable infusion pumps are available that allow patients to be discharged with the catheter in place and infused. Questions regarding patient selection and safety are being investigated.¹¹

Investigational drugs

Drugs with more prolonged effects are currently in research, as are liposome-encapsulated local anesthetics and narcotics with slow release, of which the first to be released was DepoDur (morphine sulfate extended-release liposome injection; Endo Pharmaceuticals Inc, Chadds Ford, Pa) for epidural use. DepoDur is said to provide 48 hours of analgesia, but this drug also has the typical side-effect profile of epidural narcotics. DepoDur use has been reported in patients undergoing hip repacement¹² and knee replacement,¹³ but its role in regional postoperative pain management is still to be determined.

REFERENCES

Section 8 of 8

• Authors and Editors
• Introduction
• Neuraxial Analgesia
• Peripheral Nerve Blocks
• Wound Infiltration
• Analgesic Options for Specific Surgeries
• Practical Aspects
• References

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Article Last Updated: May 1, 2007