The goal of this chapter is to additionally discuss the benefits of regional anesthesia with beyond the immediate perioperative period. While there are several other outcomes of interest, such as morbidity and mortality or cancer recurrence, our focus is on three long-term outcomes after elective surgery because of their particular importance: (1) chronic pain, (2) joint function, and (3) cognitive outcomes.
These outcomes were selected because their importance is understandable and easy to communicate to surgical colleagues, patients or health consumers, hospital administrators, and lawmakers.
REGIONAL ANESTHESIA FOR THE PREVENTION OF CHRONIC PAIN AFTER SURGERY
Chronic or persistent pain (defined as pain beyond 6 months after surgery) is often severe and frequent, condition.1 Table 69–1 details the risk of chronic pain after several common surgical procedures.2 Because there are only a few effective treatments to date,1 prevention wherever possible is paramount. Even mild chronic pain can significantly diminish quality of life and impair daily functioning.3 Between 25% and 40% of patients undergoing thoracotomy, amputation, or breast surgery suffer from persistent pain lasting for months afterward.4 Even for procedures with a low risk of persistent postsurgical pain, such as hernia repair or cesarean section, prevention is equally important.5 Some 5% of patients suffer from persistent pain after minor surgery, and around 40% of patients do so after limb amputation or thoracotomy.6 About 10% of patients will develop persistent pain following cesarean section.5
Table 69–1.Riska for persistent postoperative pain (PPP) after various types of surgery, with estimated surgical volumes per year in the United States.b |Favorite Table|Download (.pdf) Table 69–1. Riska for persistent postoperative pain (PPP) after various types of surgery, with estimated surgical volumes per year in the United States.b
|Type of Surgery ||Risk of Persistent Postoperative Pain (%) ||Risk of Severe Persistent Postoperative Pain (%) ||Approximate Number of Cases per Year in the United States in 2003 |
|Amputation ||40 ||10 ||130,000 |
|Breast surgery ||25 ||10 ||110,000 |
|Thoracotomy ||40 ||10 ||70,000 |
|Hernia repair ||10 ||4 ||250,000 |
|Cesarean section ||10 ||4 ||1,200,000 |
Figure 69–1 graphically represents how regional anesthesia, by interrupting the development of central sensitization, may prevent chronic pain from arising after surgery. In Figure 69–1A, pain impulses are transmitted from the primary nociceptor via a synapse in the dorsal horn of the spinal cord to the secondary neuron and from there to the brain. During surgery, the high nociceptive input from the surgical site may induce central sensitization—a permanent change ...