Peripheral Nerve Blocks in Lower Extremity Orthopaedic Surgery

Brent Lanting, M.D., FRCSC
Western University
London, ON

James L. Howard M.D., MSc, FRCSC
Assistant Professor
Western University
London, ON

Introduction
Regional anaesthesia is an increasingly utilized form of anaesthesia. Lower extremity peripheral nerve blocks are conducted with the objective of administering a small dose of local anaesthetic to a specific nerve via a controlled approach to provide adequate anaesthesia for the procedure required.

 

Benefits
Lower extremity peripheral nerve blocks have numerous benefits. These blocks allow diminished opioid use and reduce the associated side effects such as vomiting, confusion, urinary retention, sedation and respiratory depression1. This has potentiated early rehabilitation and short-term gains in mobility, potentially allowing shorter hospital stays2. Also, patient satisfaction and pain control is significantly improved in the immediate postoperative phase1.

Risks
The most common problem with peripheral nerve blocks is inadequate anaesthesia, occurring in about 10% of patients in larger series, but with a wide range of reported values3,4. The second most common complication is vascular puncture with potential for local haematoma at about 5%5. Although rare, the most concerning complication for the patient is the potential for nerve damage. Neuropathy can be secondary to intra-fascicle injections or direct trauma from the needle6. Nerve injuries occur less frequently in lower extremity blocks compared to upper extremity blocks, with an incidence of less than 0.5% in lumbar plexus, femoral, sciatic and popliteal nerve blocks7. Nerve injury typically is transient, with rare patients experiencing only partial recovery7. Although the nerve block catheters have high colonization rates8, local infections are rare and can readily be treated with antibiotics9.

Patient Factors
Lower limb blocks may not be appropriate if there is altered anatomy such as femoral nerve blocks in the setting of prior femoral vascular surgery, pre-existing nerve pathology6, or coagulopathic patients10. Patients that require careful postoperative neurologic monitoring may also not be appropriate, and consultation with the operative surgeon is required. Examples of patients that require close postoperative monitoring include patients who are going to have a significant valgus mal-alignment corrected by an osteotomy or a total knee arthroplasty or in patients with a high hip centre that may be lengthened during their total hip arthroplasty. Also, lower extremity blocks may not be appropriate in trauma patients who require postoperative monitoring for compartment syndrome11.

Technique
The goal of peripheral nerve blocks is to administer a small amount of local anaesthetic to a specific target. Peripheral nerve localization can be assisted by using ultrasound, peripheral nerve stimulation, elicitation of paraesthesia, double loss of resistance or a combination of techniques. Each technique has strengths, but a systematic review of literature indicates that ultrasound guidance provides decreased time to complete block with potentially fewer passes, a reduction in the volume of local anaesthesia used, and a higher success of the block for femoral and popliteal sciatic nerves4. Targets for the nerve blocks include the lumbar plexus, femoral, lateral femoral cutaneous, obturator, saphenous, sacral plexus, tibial, peroneal, posterior femoral cutaneous, and ankle nerves12. A variety of long-acting local anaesthetics have been used with similar effectiveness but different levels of potency and duration13.

Conclusions
Lower extremity peripheral nerve blocks are a safe method of providing excellent pain control without necessitating systemic narcotics. Improved immediate postoperative mobility with the resultant shorter hospital stays and an improved patient experience in the immediate postoperative phase may lead to an increased utilization of this treatment modality in the anaesthetist's armamentarium.

References

  1. J.M. Richman, S.S. Liu, G. Courpas, R. Wong, A.J. Rowlingson, J. McGready, S.R. Cohen, C.L. Wu. Does continuous peripheral nerve block provide superior pain control to opioids? A meta-analysis. Anesthesiology and Analgesia 2006; pp. 102:248-257.
  2. X. Capdevila, Y. Barthelet, P. Biboulet, Y. Ryckwaert, J. Rubenovitch, F. d'Athis. Effects of perioperative analgesic technique on the surgical outcome and duration of rehabilitation after major knee surgery., Anaesthesiology 1999; pp. 91:8-15.
  3. M.J. Fredrickson, D.H. Kilfoyle. Neurologic complication analysis of 1000 ultrasound guided peripheral nerve blocks for elective orthopaedic surgery: a prospective study. Anaesthesia 2009; pp. 64: 836-844.
  4. F.V. Salinas. Ultrasound and review of evidence for lower extremity peripheral nerve blocks. Regional Anesthesia and Pain Medicine 2010; pp. 35:2(1); S16-25.
  5. M. Wiegel, U. Gottschaldt, R. Hennebach, T. Hirschberg, A. Reske. Complications and adverse effects associated with continuous peripheral nerve blocks in orthopedic patients. Anesthesia and Analgesia 2007, pp. 104:15; 78-82.
  6. C.L. Jeng, T.M. Torrillo, M.A. Rosenblatt. Complications of peripheral nerve blocks. British Journal of Anaesthesia 2010; pp. 105(S1):i97-i107.
  7. R. Brull, C.J.L. McCartney, V.W.S. Chan, H. El-Beheiry. Neurologic complications after regional anesthesia: Contemporary estimates of Risk. Anesthesia and Analgesia 2007; pp. 104:4; 965-974.
  8. P. Cuvillon, J. Ripart, L. Lalourcey, E. Veyrat, J. L'Hermite, C. Boisson, E. Thouabtia, J.J. Eledjam. The continuous femoral nerve block catheter for postoperative analgesia: Bacterial colonization, infectious rate and adverse effects. Anesthesia and Analgesia 2001; pp. 93: 1045-1049.
  9. A.M. Morin, K.M. Kerwat, M. Klotz, R. Niestolik, V.E. Ruf, H. Wulf, S. Zimmerman, L.H.J. Eberhart. Risk factors for bacterial catheter colonization in regional antesthesia. BioMedical Central Anesthesiology 2005; pp. 5: 1-9.
  10. T.T. Horlocker, D.J. Wedel, J.C. Rowlingson, F.K. Enneking. Executive summary: Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine evidence-based guidelines (third edition). Regional Anesthesia and Pain Medicine 2010; pp. 35(1): 102-105.
  11. J.M. Murray, S. Derbyshire, M.O. Shields. Lower Limb Blocks. Anaesthesia 2010; pp. 65 (Suppl. 1) 57-66.
  12. Q.H. DeTran, A. Clemente, R.J. Finlayson. A review of approaches and techniques for lower extremity nerve blocks. Canadian Journal of Anesthesia 2007; pp. 54:11; 922-934.
  13. G. Fanelli, A. Casati, P. Beccaria, G. Aldegheri, M. Berti, F. Tarantino, G. Torri. A double-blind comparison of Ropivacaine, Bupivacaine, and Mepivacaine during sciatic and femoral nerve blocks. Anesthesia and Analgesia 1998; pp. 87: 597-600.

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