Chapter 65. Anesthesia for Orthopedic Surgery

1. Orthopedic surgery is associated with high incidences of deep venous thrombosis and pulmonary embolism.

2. The need for anticoagulation results in anesthesia issues specifically related to the potential for neuroaxial hematomas.

3. Unique complications in orthopedic surgery are related to tourniquet use and fat embolism.

4. Regional anesthesia is associated with lower morbidity and mortality than is general anesthesia.

5. Prone spinal surgery cases have unique complications related to patient positioning, such as nerve injuries, ventilation problems, and blindness.

Orthopedic anesthesia presents many challenges to anesthesiologists. Patients range in age from infant to centenarian. This patient population shows the full spectrum of comorbidities. Many of the procedures are associated with significant postoperative pain. Surgery on isolated extremities can be performed using a variety of regional anesthetic techniques for both anesthesia and postoperative analgesia. However, providing adequate analgesia using central neuraxial techniques can be challenging, especially when deep venous thrombosis (DVT) prophylaxis with low-molecular-weight heparin (LMWH) is needed. This challenge has led to the development of many peripheral nerve block techniques and advances in the equipment used for these techniques, including continuous nerve catheters and ultrasonography for identification of nerve plexuses. Recent literature has shown a benefit of regional anesthesia over general anesthesia with respect to mortality, morbidity, postoperative analgesia, and functional recovery. The use of ultrasonography to place nerve blocks may offer a significant advantage over peripheral nerve stimulation. A meta-analysis looking at the advantage of ultrasonography over nerve stimulation technique showed improved efficacy in respect to onset and quality of block.1 It also appears that the minimum amount of local anesthetic required to successfully perform the nerve block may be greatly reduced by using ultrasonography instead of the traditional nerve stimulation technique.2 This may be of great benefit in reducing the incidence of local anesthetic toxicity. This chapter considers the factors pertinent to anesthesia for orthopedic surgery and reviews the appropriate management.

Rheumatoid Arthritis

Because of the nature of the disease, patients with rheumatoid arthritis present for many orthopedic procedures, ranging from joint replacement surgery to cervical spine surgery. These patients can be very challenging to treat for a variety of reasons. Deformities of the extremities are common, which may make arterial and intravenous (IV) access and positioning of the patient more difficult. Great care must be taken when positioning patients, with adequate padding needed to prevent pressure necrosis of the patient's skin. Positioning the patient while he or she is awake often is useful. Of major concern in any patient with rheumatoid arthritis is the possibility of cervical spine instability.3 Cervical spine involvement occurs in more than half of patients with rheumatoid arthritis, with atlantoaxial dislocation the most common abnormality. Pain and evidence of spinal cord injury are the main symptoms and signs of cervical spine involvement. However, the presence of symptoms may not correlate with the severity of radiologic abnormalities. Computed tomography and magnetic resonance imaging provide detailed images of the bone and ...