Introduction

Postoperative pain management is a crucial part of any surgical procedure and may directly impact patient satisfaction and outcome. Numerous new techniques and medications are continuously being developed in an attempt to streamline the process. These will invariably lead to shorter postoperative stays and less dependence on narcotic pain medications. Traditional systemic methods of pain control are not without their potential side effects, including altered mental status, narcotic dependence, nausea, constipation, depressed respiratory drive, and emesis. The potential to minimize these side effects is one of the many advantages to alternative forms of pain control in the critical first 5 to 7 days postoperatively.

The epidemic of obesity in the United States has led to a rapid increase in the number of bariatric procedures performed over the past several years. The dramatic changes to the torso following massive weight loss are only partially addressed by routine procedures such as abdominoplasty and liposuction. Circumferential body lifts or simultaneous abdominoplasty, thigh, and buttock lifts are becoming the method of choice for treating the postbariatric condition.

Body contouring as outpatient surgery has become possible because of the significant advances in the safety of anesthesia and effective pain and nausea management. Although the recent increase in the use of infusion pumps for postoperative pain control is popular, its use is not universal. Studies show that the differences in perception of postoperative pain may be patient-specific. The goal following each surgery is early ambulation and improved pulmonary physiology. In an effort to achieve these goals, improved postoperative pain control following body contouring can help minimize complications.

As with all body-contouring procedures, complications can and do occur. The most devastating complication of body contouring is pulmonary embolus. This complication is thought to be directly related to the degree of plication of the rectus fascia, which can cause intraabdominal hypertension (i.e., >20 mm Hg). The increased pressure has deleterious effects on the venous circulation by causing stasis and decreasing venous return, thus predisposing the patient to deep venous thrombosis (DVT). Therefore, improved pain control postoperatively can alleviate some of this pain and increase the patient’s activity.

Comorbid factors play a significant role. Patients who smoke or have diabetes, hypertension, a body mass index (BMI) >30 kilograms per height in meters squared (kg/m²), or asthma have significantly higher complication rates. More aggressive management may be necessary for these patients with comorbid conditions. Since body contouring is an elective procedure, patient selection must include consideration of multiple risk factors. As patient requests for multiple simultaneous procedures increase, so do the concerns about potential complications as a result of these combined procedures. One way to minimize complications is to improve pain control and maximize early ambulation.

Approaches

Postoperative pain, or any pain for that matter, can be managed by five different approaches. The first approach is the central approach, wherein pharmacologic agents (e.g., narcotic analgesics) are administered systemically and act by altering the perception of pain in the central nervous system. This method has all of the disadvantages and risks associated with the use of these pharmacologic agents, including sedation, respiratory depression, nausea, and vomiting.1 The second approach involves the use of neuraxial blockade (i.e., spinal or epidural analgesia), which acts by blocking or altering the transmission of pain impulses from the spinal cord to the brain. The disadvantages of this method include sympathetic blockade leading to possible hypotension, motor blockade possibly interfering with ambulation, urinary retention, the risk of spinal headache, and the risk of respiratory depression with the use of narcotics. The third approach is peripheral nerve blockade, such as axillary block or femoral nerve block, which acts by blocking the transmission of nerve signals to the central nervous system. The disadvantages of these methods include the complexity of performing these procedures, the risk of neuropathy with the prolonged presence of a catheter and/or local anesthetic in proximity to a major nerve, and the risks of the blocks themselves (e.g., phrenic nerve block and elevated hemidiaphragm with interscalene block). The fourth method is the application of local anesthetic at the site of injury, which blocks the transmission of pain signals at the local level. This method is safe and free of systemic side effects. The only risk associated with this method is that of local anesthetic toxicity should excessive amounts of local anesthetic be infused. The fifth method is the application of pulsed electromagnetic field therapy. This is a portable, noninvasive modality that has shown promise in many areas, including in the management of pain control.2–5

Because postbariatric patients cannot tolerate certain medications (e.g., nonsteroidal antiinflammatory drugs [NSAIDs]), other modalities in decreasing pain are even more important in this specific population to avoid narcotic analgesic side effects. In addition, as many patients are given preoperative or perioperative anticoagulants for DVT prophylaxis, some centers do not perform adjunctive invasive procedures for pain control due to the higher risk of bleeding. Therefore, the remainder of this chapter is focused on management of pain control with infusion pumps and pulsed electromagnetic field (PEMF) therapy, which are becoming the primary devices used in these patients.

Infusion Pumps

Effective postoperative analgesia is a prerequisite to enhance the recovery process and reduce morbidity. The use of local anesthetic techniques is well documented to be effective, but single-dose techniques (e.g., infiltration, peripheral blocks, and neuraxial blocks) have been of limited value in major operations because of their short duration of analgesia.

The important question is whether we have enough evidence to more widely recommend continuous local anesthetic wound infusion techniques in our perioperative care programs. The primary risk from peripheral infusions of local anesthetics is direct tissue toxicity such as myotoxicity. Although there are supportive laboratory data, the clinical experience is that such injuries are rare.1 On the other hand, continuous local anesthetic wound infusion in minor procedures such as inguinal herniorrhaphy may not be cost-effective despite proven efficacy.1,6 Instead, in such minor procedures we should strive to implement effective oral multimodal nonopioid analgesia, which is more simple to manage and can be continued for a longer period when necessary than the usual wound infusion regimens of 2 to 3 days’ duration.1,6

The pain-control infusion pump has been used following both cosmetic and reconstructive procedures.7–9 It is designed to deliver a continuous supply of local anesthesia directly into the surgical wound. Although this device is shown to be effective for postoperative pain control in orthopedic surgery, general surgery, and podiatric surgery, the safety and morbidity data following plastic surgery procedures remain limited.10–15 Concerns have been raised regarding the potential ischemic or infectious complications of placing a catheter beneath the operative site for infusion of local anesthesia with or without epinephrine.

The Anesthesia Patient Safety Foundation has recently released a position statement highlighting potential risks of respiratory depression with systemic and central neuraxial opioid analgesia.16 Use of continuous local anesthetic wound infusion techniques, especially with concomitant use of several nonopioid analgesics, may thus directly improve patient safety. Importantly, the optimal duration of wound local anesthetic infusion must be evaluated together with the effect on relevant outcomes.

All drug delivery system pumps are disposable and ambulatory. They are portable devices designed to infuse local anesthesia continuously into the operative site. The potential indications for continuous pain-control infusion in plastic surgery are many. It can be used in the inpatient or outpatient setting for reconstructive and cosmetic surgery. Information regarding the pain-control infusion pump in the literature are limited and, at times, controversial. Most reports have been anecdotal, with limited objective data evaluating this device.8,9 Baroody et al7 demonstrated a fivefold decrease in oral and intravenous pain medication use with the pain pump in immediate latissimus dorsi flap reconstruction following mastectomy. Patients who used the pain pump had a twofold lower pain level with less nausea and emesis compared with controls.

Use of this postoperative pain system following augmentation mammaplasty is beneficial, given the direct delivery of local anesthesia to the operative site. The pain-pump catheter is rolled up in the implant prior to its insertion into the desired location. It is then inserted with the implant and brought out through the incision. There were no complaints of skin rash, hives, redness, swelling, or discharge at the catheter site, or increased pain. Concerns about indwelling catheters in the implant pocket with regard to infection and capsular contracture are important and need to be addressed with long-term studies.

Effective postoperative analgesia will directly affect patient satisfaction and, subsequently, the length and nature of the recovery period. Preemptive analgesia (i.e., the blocking of pain before it begins) reduces the postoperative pain even after the particular analgesic has dissipated.8,9 This might be in the form of either patient-controlled analgesia (PCA) or pain-pump infusions. PCA has improved postoperative pain management, given that the patient has direct involvement and is able to self-administer narcotics without relying on additional assistance. Concerns have been raised regarding the infectious morbidities that might be associated with the percutaneous nature of the infusion pump or caused by retaining a piece of the catheter at the surgical site. Epinephrine is not routinely added to the local anesthesia, eliminating the potential for ischemic complications as reported previously.17 It has been postulated that patients with marginal peripheral circulation may be at increased risk of tissue necrosis along the wound site when epinephrine is added to the continuous infusion.

The pain-control infusion pump delivers a continuous infusion of local anesthetic to the surgical site. Just prior to closure, a very fine (20-gauge) multiport catheter is placed into the area. If two catheters are placed, then the catheters are connected via a Y-connector to a flow rate restrictor and then to a 100 mL spring-loaded syringe reservoir. The catheters cannot be connected to the reservoir without first connecting a flow rate restrictor, thereby preventing accidental overdosage. The flow rate restrictors are available in sizes of 0.5 mL per hour, 1 mL per hour, 2 mL per hour, and 4 mL per hour, allowing for the use of this device in a variety of surgical procedures. We use two 2 mL per hour flow rate restrictors, which each deliver a constant 2 mL per hour infusion of local anesthetic. The reservoir is filled with 100 mL of 0.25% bupivacaine. The patient is therefore receiving 10 mg (4 mL per hour × 2.5 mg/mL) of bupivacaine per hour or 240 mg per 24 hours. This is well below the established maximum dose of bupivacaine of 400 mg per 24 hours. The catheters are left in place and continue the infusion for 48 hours, at which point the catheters are removed.

Recently, Liu et al6 performed a meta-analysis of 2141 patients in 44 randomized controlled trials and found the incidence of wound infections among pain pump catheters to be 0.7%, which was comparable to controls (1.2%). The use of the pain pumps with transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction procedures was also studied.18 Surgeons divided the TRAM patients into two groups: PCA was administered to all patients, but the pain pump was only applied to one group. The authors found that the patients with the pain pump were discharged earlier, experienced half the pain, and noted reduced nausea. They also looked at their previous abdominoplasty cases with patients who used the pain pump and those who did not. Again, there was a faster recovery and no infections at the pain-pump site.

Organizations such as the Joint Commission on Accreditation of Healthcare Organizations and numerous anesthesia societies have stood at the forefront in recent efforts in the aggressive evaluation and treatment of postoperative pain. The traditional methods of pain control, specifically oral and intravenous narcotics, have proven palliative but carry several unwanted side effects. Altered mental status, suppressed respiratory drive, narcotic dependence, nausea, emesis, and constipation are among them.