Enhanced recovery after surgery (ERAS) protocols in breast surgery: techniques and outcomes

What is pain?

Pain is defined as “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”. In an update from commonly held notions, the International Association for the Study of Pain (IASP) states that pain and nociception are different experiences. Pain is an individualized phenomenon that is influenced by an individual’s past experiences, while nociception is a physiologic activity that occurs in the nervous system as a response to noxious stimuli. Lastly, the IASP states that in excess, pain may negatively impact a patient’s functional, social, and psychosomatic wellbeing.

The impact of pain on a patient can be broken down into three categories: physiologic, psychosocial, and postoperative recovery. The physiologic response to pain can lead to impaired ventilation and constipation, higher rates of postoperative nausea and vomiting (PONV), increased rates of deep vein thrombosis (DVT) and urinary retention, and impaired immune response, leading to increased rates of postoperative infections and wound-healing issues. Uncontrolled pain can exacerbate pre-existing psychiatric conditions as well as lead to the development psychosocial issues, as these patients are more likely to isolate themselves from others. In the acute phase, uncontrolled pain can delay discharge from the postanesthesia care unit (PACU) and hospital while increasing the rate of hospital readmissions.

To address these concerns, pain management protocols consisting of multimodal analgesia have been developed across all surgical specialties, with the goal of appropriately managing pain, decreasing opioid consumption, and decreasing patient length of stay. This chapter will focus on the components of an ERAS protocol and present the most recent findings of multimodal analgesia regimens for plastic surgery procedures of the breast.

Opioids

Opioids have historically been the gold-standard for postoperative pain control, with receptors found in the central nervous system, peripheral nervous system, and enteric nervous system. The primary neurotransmitters involved in the sensation of pain are substance P and glutamate in the central nervous system. Pharmacologic opioids mimic endogenous opioids and, through a complex set of reactions, result primarily in the inhibition of neurotransmitter release and secondarily in the prevention of excitatory signals. As such, opioids have traditionally been popular methods of pain control with oral, intravenous, and patient-controlled analgesia (PCA) routes of administration. Despite their efficacy, opioids have various side effects, including constipation, nausea and vomiting, drowsiness. Furthermore, opioids have proven to be addictive, account for the majority of illicit drug overdoses, and negatively affect patients in terms of quality-of-life and healthcare costs. As the years have passed, it has become more evident that opioids are part of the problem, rather than the solution, to pain control. This has led to efforts to study provider prescribing patterns and standardize perioperative pain management at the institutional level.

ERAS

To appropriately address postoperative pain and decrease opioid consumption, multimodal analgesia regimens have been created that address the subjective experience of pain, while managing the physiologic and noxious stimuli that lead to pain. These multimodal analgesia protocols have come to be known as “enhanced recovery after surgery” or “ERAS” protocols. The overarching themes between the various ERAS protocols in circulation today are preoperative education, perioperative non-narcotic analgesia, intra-operative local or regional anesthesia, and early postoperative ambulation.

ERAS protocols were originally conceived to decrease patient length of stay during the postoperative phase. To that end, Liu et al . studied 52 patients in a randomized control trial (RCT) to examine the effect that various adjunct anesthetics had on patient length of stay. They found that patients who received local anesthetic met discharge criteria 1.5 days earlier than those who did not. In 1998, Pavlin et al . prospectively analyzed adult outpatient procedures to determine causes of discharge delay. The authors determined that the most important factor in a discharge delay was the method of anesthesia (i.e. general vs. local infiltration vs. nerve block vs. neuraxial anesthesia).

The earliest iterations of ERAS protocols were introduced and put into practice in the field of colorectal surgery during the 1990s and early 2000s. Across the board, ERAS protocols have demonstrated decreased patient length of stay, costs, and opioid use. In a 2009 review article on ERAS in colorectal surgery, authors determined several aspects of care that are critical to a successful ERAS protocol, these include preoperative counseling, local or regional anesthetic blocks, minimization of postoperative opioid use and control of PONV, and early mobilization protocols, much of which have been carried over to plastic surgery ERAS protocols. Multimodal analgesia has proven to be a safe, efficient, and reproducible way to decrease opioid usage in the perioperative setting in various fields, including neurosurgery, hepatobiliary, bariatric, urologic, colorectal, and major oncological resections. Similarly, plastic surgeons have begun incorporating aspects of ERAS protocols into their practices to cut down on excessive opioid prescriptions.

In the effort to remove sources of excess opioids, authors have been studying physician prescribing patterns. The incorporation of ERAS protocols has seen 40%–100% reductions in prescribed perioperative opioids, among various other benefits. When applied to implant-based breast reconstruction, Lombana et al . demonstrated that patient within an ERAS protocol spent significantly less time in the PACU (68.47 min vs. 103.95 min; P = 0.006) than non-ERAS patients and are prescribed significantly less opioids upon discharge ( P = 0.017). Furthermore, analyzing 136 patients undergoing outpatient plastic surgery breast procedures, Wong and Saint-Cyr found that, compared with non-ERAS patients, those within an ERAS protocol consumed 16.6 OMEs versus 23.3 OMEs in the PACU ( P = 0.005) and were prescribed 41.5% less opioids than non-ERAS patients ( P <0.0001). Despite these positive findings, recent data has shown that among non-plastic surgery and plastic surgery procedures, over half of all opioids prescribed are not consumed and a third of patients do not use any opioids in the postoperative phase.

In addition to decreasing patient opioid consumption, ERAS protocols have robust data demonstrating their positive effects on patient pain, length of stay, time to ambulation, and healthcare costs. Regarding healthcare costs, Oh et al . demonstrated costs saving of $4576 per patient when ERAS protocols are used in microsurgical breast reconstruction. Recommendations focus on optimizing patients in each phase of their preoperative, intra-operative, and postoperative course. Interestingly, Shin et al . demonstrated that as a patient’s BMI increases, so too does the benefit they receive from ERAS protocols, with class 1 obesity patient’s experiencing a LOS decrease of 0.99 days ( P = 0.048) and class II+ obesity patients experiencing a LOS decrease of 1.35 days ( P = 0.093). Though the majority of ERAS recommendations are for breast reconstruction, most, if not all, have been carried over to oncoplastic and aesthetic breast procedures. In addition to the previously mentioned benefits, the implementation of ERAS protocols has seen shorter hospital and PACU recovery times, and significant patient cost savings.

Multimodal analgesia

Multimodal analgesia regimens are backed by high-level evidence with strong recommendations for their incorporation into ERAS protocols. These regimens are opioid-sparing and seek to address pain though various physiologic angles, by targeting multiple neuronal receptors in various parts of the nervous system. Perioperative non-narcotic analgesia can be broken down into the different drug classes: non-steroidal anti-inflammatory drugs (NSAIDs), cyclo-oxygenase (COX)-2 inhibitors (COXIBs), acetaminophen, gabapentinoids, and antispasmodics.

NSAIDs and COXIBs decrease surgical pain and inflammation by inhibiting the COX system and the production of downstream pain modulators, specifically prostaglandins. NSAIDS have been further refined to selectively inhibit COX-2, a major enzyme involved in the generation of post-injury hyperalgesia. These drugs have been shown to be as effective as nonspecific NSAIDs for pain control, with a lower risk of gastrointestinal (GI) side effects. Although selective COXIBs have been linked with unwanted cardiovascular complications, a large systematic review demonstrated a lower cardiovascular risk-profile of celecoxib compared with non-selective NSAIDs and other COX-2 inhibitors. However, one should exercise caution when prescribing any NSAID or COXIB to patients with high-risk cardiovascular profiles.

Thought to regulate nociception peripherally and centrally via adenosine and serotonin receptors, acetaminophen has proven to be a staple aspect of any ERAS protocol, with an effective analgesic effect and low-risk profile. Although acetaminophen has a relatively low risk-profile, one should be aware of the possibility of hepatic toxicity. Thus, the prescribing physician should practice caution when administering acetaminophen to patients with a history of hepatic dysfunction and caution all patient to avoid consumption of more than 4000 mg/day.

Gabapentinoids were originally developed as anti-convulsants and include gabapentin and pregabalin. These drugs act centrally via calcium-channel binding on neurons and inhibiting the release of pain modulators. They have proven to be useful adjunct medications in ERAS protocols and effective at controlling chronic and acute postoperative pain. These drugs have also shown promise when started preoperatively on a scheduled basis. The final component of multimodal analgesia regimens are antispasmodics. Antispasmodics inhibit postoperative muscle contraction through their antimuscarinic effects and include cyclobenzaprine and methocarbamol. The incorporation of these medications into ERAS protocols has shown promise in reducing length of stay, postoperative pain, and opioid consumption. Please see Table 42.1 for complete dosing and drug information of the various multimodal analgesics discussed above.

Local anesthesia

Local anesthetics are an important component of any perioperative pain control regimen, especially in plastic surgery. Commonly used local anesthetics include lidocaine, bupivacaine, ropivacaine, and prilocaine. The indications for each of these differs with regards to desired onset and duration of action. For example, ropivacaine has been shown to have an earlier onset of action but shorter block duration than bupivacaine. Thus, for an intra-operative block in which duration is more important than onset, bupivacaine HCl is often preferred to ropivacaine. Each of these medications can be given with or without epinephrine, attached to a biologic carrier, or in a local anesthetic cocktail. Lastly, method of administration differs depending on the intended effect of the local anesthetic. Outside of peri-incisional local anesthesia, the most common applications for local anesthesia in plastic surgery of the breast are operative site infiltration, regional peripheral nerve blocks, and neuraxial blocks.

Each method of local anesthesia administration can be further divided into sub-categories. Operative site infiltration can take the form of a one-time soft-tissue local infiltration, for example, into the breast parenchyma during a breast reduction, or as an intra-wound catheter for prolonged administration. Regional blocks can be divided by the anatomic regions of the breast and abdomen. Regional blocks that will be discussed in this chapter include PECS1 and PECS2 blocks, serratus anterior plane (SAP) blocks, intercostal nerve blocks, transversus abdominis plane (TAP) blocks, and paravertebral plane (PVB) blocks. Neuraxial blocks can be broken down into epidural anesthesia and spinal anesthesia; due to the relative lack of use within plastic surgery of spinal anesthesia, we will focus on epidural anesthesia.

All local anesthetics are composed of an amide drug of a specific concentration and dosage. Local anesthesia functions by binding to and closing voltage-gated sodium-channels on neuronal cell membranes, preventing depolarization and action potential generation. Pharmacokinetics are influenced by the pKa, lipid solubility, and protein binding of each individual agent. Onset of action is inversely proportional to pKa, i.e., agents with a lower pKa will have a more rapid onset of action, and duration of action is directly proportional to lipid solubility and protein binding. Dosing of local anesthesia is based on a patient’s weight and is unique to each individual agent. The reported maximum dose for lidocaine with epinephrine is 7 mg/kg and 4.5 mg/kg without epinephrine, and between 2 mg and 3 mg/kg for bupivacaine (with or without epinephrine). Regarding duration of action, lidocaine has been shown to provide anesthesia for 1–3 h and bupivacaine for up to 10 h. Please see Table 42.2 for complete local anesthesia dosing guidelines.