Introduction
Hip surgeries commonly treat arthritis and fractures in the hip. Pins or other fixators might be used to approximate the fractured segments in case of a hip fracture. Hip arthritis (inflammation of the hip joints) might require the removal of some parts of the bone (osteotomy), a cut in the lining of the joints (synovectomy), or replace the complete joint. However, managing the pain following these procedures can be challenging. This article deals with how lumbar plexus nerve block is used to manage pain in the postoperative period.
What Is Lumbar Plexus Block?
Lumbar plexus block is a type of regional anesthesia that dates back about 50 years. It was also called three in one block by Winnie et al. in 1973, where it was used pioneerly. The lumbar plexus marks the region where four nerves that supply the lower limbs start, in addition to the ilioinguinal and iliohypogastric nerves (they include the femoral, lateral cutaneous nerve of the thigh, obturator, and genitofemoral nerves). The nerve block is commonly used in elderly patients undergoing hip surgeries.
Consent must be obtained from the patients, as in all regional anesthesia procedures for the lumbar plexus block. It is ideally performed on awake or mildly sedative patients. However, many experts prefer to give the block even after general or spinal anesthesia. Some amount of sedation is beneficial in administering the block, as it is a deep block. It can cause discomfort or some pain as the needle has to pass through quite a reasonable amount of muscle mass. A small subcutaneous or intradermal nerve block at the point of insertion can help to reduce patient discomfort.
What Are the Contraindications of Lumbar Plexus Block?
The contra-indications (when the block should be avoided) are divided into absolute (cases where the nerve block should not be attempted) and relative (cases where they can be administered with precaution). The absolute contra-indications include:
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When the patient is not willing to undergo a nerve block.
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Allergy to the local anesthetic agent.
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Local sepsis.
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Infection at the site of needle insertion.
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The international normalized ratio (INR, which provides information on how long it takes for blood to clot) is more or less than 1.5 twelve hours after the procedure.
The relative contra-indications include:
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Systemic sepsis (a complication of an infection that can be life-threatening).
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Cardiac functioning is poor and gives poor cardiac output (the amount of blood pumped by the heart in a minute).
What Are the Complications of Lumbar Plexus Block?
For ease of study, the complications that can arise from lumbar plexus block are categorized into three, which include:
Complications Arising From Needle Puncture:
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Direct Trauma to the Nerves: This is a very rare complication, which may occur in 1:5,000 cases. This can be prevented by the use of a short-beveled needle for injection.
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Intra-neural Injection: This can result in nerve damage, especially the injections given at high pressure.
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Damage to the Abdominal Viscera: In some cases, damage to the kidney has been reported despite following the proper anatomical landmarks.
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Retroperitoneal Hematomas: These are possible complications.
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Psoas Abscess: It is a rare complication when followed with proper aseptic measures. However, if it occurs, deep infections can be difficult to treat.
Complications From Incorrect Local Anaesthetic Placement:
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Epidural Spread: It is common and can be due to the direct injection of the anesthetic agent into the epidural space. A profound misplaced local anesthesia can cause cardiovascular collapse.
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Spinal Injection: Total spinal injection can be caused by a high volume of local anesthetic agent injected into the CSF (cerebrospinal fluid) space. It can cause cardiovascular collapse, apnoea, seizures, and loss of consciousness.
Complications From Incorrect Local Anesthetic
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Intravascular Injection and la Toxicity: Studies show that the plasma concentration of the local anesthetic agent remains below the toxic levels following a posterior lumbar plexus block. They usually remain below the toxic levels even if used along with a proximal sciatic nerve block.
How Efficient Is Lumbar Plexus Block for Post-operative Analgesia Following Hip Surgery?
Studies show that lumbar plexus blocks are more efficient in reducing pain in the postoperative period of hip surgery. It helps to reduce pain when compared to opioids in the first four to eight hours. This can be extended using a continuous infusion through a catheter. It was seen that a single lumbar plexus block was above the efficiency of a femoral nerve block and was associated with a more consistent block of the obturator nerve. Hence, it is considered a powerful and reliable tool for postoperative pain management, especially the pain following hip surgery.
It reduces the opioid consumption and improves patient comfort. In addition, it helps in better post-operative ambulation and provides better patient compliance in physical therapy. However, proper knowledge of the anatomical structures, contra-indications, and indications of the lumbar plexus block is essential to avoid complications.
Relieving pain following hip surgery requires interprofessional skills, where the surgeon, the nurses, the physical therapist, and the anesthesiologist function as a team. They can discuss and plan for the best strategy that may be beneficial to the patient and aid in faster recovery. Enhanced recovery after surgery (ERAS) is defined as the many steps taken to achieve faster and better recovery of the patient following surgery. Using a lumbar plexus block after hip surgery reduces opioid consumption, nausea and vomiting following the surgery, and the exposure of naive patients to opioids.
Conclusion
The hip is innervated mainly by branches of the lumbar plexus: the femoral nerve, obturator nerve, and the lateral femoral cutaneous nerve. The other nerves that innervate the hip include the sacral plexus via the nerve to the quadratus femoris and, at times, directly through the sciatic nerve. Anesthetizing these nerves can help to reduce post-operative pain following hip surgery. However, a thorough knowledge of the anatomical structures, contraindications, and indications of the block must be considered to prevent complications. Using this block helped to reduce patient discomfort, reduces opioid consumption, and nausea and vomiting following the surgery. Furthermore, it helps in better post-operative ambulation and provides better patient compliance in physical therapy, as the muscles are relaxed.
