The 2014 census by the American Society for Aesthetic Plastic Surgery (ASAPS ) records the number of lipoplasty procedures for that year to be 342,494. Liposuction ranks as the number one most popular cosmetic surgical procedure performed on an annual basis in the United States. Liposuction has seen a 94 % increase in the number of procedures performed since ASAPS initiated its first survey in 1997.

Tumescent liposuction involves infusion of a solution of diluted local anesthetic into the subcutaneous fat layer. This serves to hydrate the fat layer in preparation for aspiration. Then fat is removed from the targeted areas by the aspiration through microcannulas [2, 6]. The tumescence solution typically consists of 1 l of normal saline containing 500–1000 mg of lidocaine , 0.25–1.0 mg of epinephrine , and 12.5 mmol of sodium bicarbonate [2, 7]. Its components provide prolonged local anesthesia and minimize blood loss. Large-volume liposuction, defined as the removal of more than 5000 ml of fat, may require the infusion of several liters of this solution [6, 8].

Historically, the maximum “safe” dose of subcutaneous lidocaine injection has been limited to 4.5 mg/kg without epinephrine and 7.0 mg/kg with epinephrine [9]. This topic has been the source of considerable confusion for clinicians and between plastic surgeons and anesthesiologist not familiar with local anesthesia in cosmetic plastic surgery. Multiple factors, such as the concentration of the local anesthetic, dilution of the local anesthetic, site(s) of injection, etc., affect the maximum safe dose of local anesthetics.

Lidocaine has a long-term, excellent safety record in dentistry and several surgical procedures [8, 10]. Tooth extraction and oral surgery, skin excisions, hand surgery, and liposuction can be performed under local anesthesia without the need of either general anesthesia or IV sedation [8, 10–12]. The maximum safe dose of lidocaine in liposuction by the tumescent technique is considerably higher than what is recommended with dry techniques (7 mg/kg). Studies by Klein have shown that even high doses of lidocaine tumescence anesthesia of 35 mg/kg [13] and 55 mg/kg [8] for large volume liposuction are safe since the peak lidocaine serum levels (average 2.37 μg/ml) remained below the threshold for subjective toxic levels (3 μg/ml). According to the author, large doses of lidocaine can be administered safely during tumescent liposuction because of dilution by the wetting solution, slow infiltration into a poorly vascularized space, and the vasoconstrictive effect of epinephrine , which delays and diminishes systemic absorption of the drug. The slow absorption curve of lidocaine in this situation keeps its peak blood level low and prolongs its effect in peripheral tissue. Several authors have replicated these findings [14–16].

Studies by Burt and Vasconez et al. have shown the safety of combining tumescence liposuction surgery with esthetic plastic surgery of the face and breast that requires infiltration of additional lidocaine with epinephrine [17]. In their study, when patients were infiltrated tumescence anesthesia consisting of lidocaine with epinephrine in normal saline with a mean dose of 22.9 mg/kg (range of 11.2–38.3 mg/kg) and additional 0.5 % lidocaine with epinephrine was infiltrated in the face, breast, or abdomen (additional average dose 5.38 mg/kg, range 0.4–12.1 mg/kg), the peak levels of lidocaine were safely below 3 μg/ml [17]. No patient presented subjective clinical signs of lidocaine toxicity.

Swanson also has reported the safety of lidocaine and bupivacaine used as tumescence solution containing epinephrine in patients undergoing liposuction and abdominoplasty [18]. In his prospective cohort, patients received infusions containing 0.05 % lidocaine (liposuction) and/or 0.025 % bupivacaine (abdominoplasty) with 1:500,000 epinephrine. Plasma levels of lidocaine, bupivacaine, and epinephrine were studied in 76 consecutive patients. The maximum lidocaine dose was 3243 mg and the maximum level was 2.10 μg/ml. The maximum bupivacaine dose was 550 mg and the maximum level was 0.81 μg/ml. No clinical toxicity was encountered.

Caution must be exercised when injecting local anesthetics in patients with liver disease because their ability to metabolize local anesthetics is impaired. The t1/2 for lidocaine following IV administration in healthy patients is 1.4 h and increases to 7.3 h in patients with active hepatitis [19]. The clearance of ropivacaine is decreased by 60 % in patients with end-stage liver disease compared with healthy volunteers [20]. Single-injection techniques using the recommended doses of local anesthetics are safe in patients with hepatic dysfunction. However, repeated injections may increase the risk of toxicity, thus the subsequent doses should be decreased. Renal function also affects the local anesthesia toxicity. The half-life of the lidocaine metabolites can increase and therefore cause central nervous system toxicity. The dose of local anesthetic should be reduced by 20–30 % in uremic patients even with single-injection techniques, and especially when large doses of drugs are usually required .

Abdominoplasty, traditionally performed in the inpatient setting, is becoming an outpatient procedure with advancements in anesthetic and surgical techniques. Early discharge to home, decreased costs, and proven safety in performing such procedures in the outpatient setting are the proposed reasons for this trend. Using local or regional anesthesia techniques in abdominoplasties, multiple authors have described the avoidance of traditional inhalational general anesthesia [21–23]. Michaels and Eko described the use of use of rib blocks with conscious sedation to facilitate abdominoplasty in the outpatient setting with excellent results [21]. Mustoe et al. detailed the use of conscious sedation and local anesthesia for abdominoplasties, with extremely good outcomes and almost no unplanned hospitalizations, and with high patient satisfaction rates [22]. Rosenberg et al. described 106 abdominoplasties performed with procedural sedation and local anesthesia [23].

Hand surgery has been traditionally performed under either general anesthesia or IV sedation or local anesthesia. Lalonde et al. have shown that it is possible to perform successful wide-awake hand surgery under local anesthesia without the need of IV sedation or general anesthesia [11, 24, 25]. The author has shown that is it possible to perform hand tendon repair under pure local anesthesia without the use of tourniquet or any type of sedation or other anesthesia modality [11]. Chan et al. have also shown that carpal tunnel release can be successfully performed under local anesthesia using either lidocaine or ropivacaine [26].

Traditional medical texts have perpetuated the belief that local anesthesia containing epinephrine should not be injected in fingers, toes, ears, and nose [27, 28]. All of the evidence for the antiadrenaline dogma comes from 21 mostly pre-1950 case reports of finger ischemia associated with procaine and cocaine injection with epinephrine. Thompson et al. performed an in-depth review of the literature surrounding this topic [29]. They carefully examined each of the 48 cases of digital necrosis cases associated with local anesthesia. Of those 48 patients, 21 had epinephrine injected with the local anesthetic. The fact that there were actually more cases of local anesthetic-related digital infarction in which epinephrine was not involved leads to the logical conclusion that epinephrine was not the only factor inducing digital necrosis in the time period before 1950 when 42 of these cases occurred. Almost all of the 48 cases of finger death associated with local anesthetics involved procaine. Procaine or cocaine is known to potentially cause digital infarction . However, the fact that finger infarction was linked to the use of adrenaline established the dogma, based on invalid evidence, of “avoiding the use of epinephrine in fingers.”

Lalonde et al. performed a prospective multicenter study to examine the incidence of digital infarction in a large series of patients in whom local anesthesia with adrenaline was injected electively into the hand and fingers from 2002 to 2004. A total of 3110 consecutive cases of elective injection of low-dose epinephrine (1:100,000 or less) in the hand and fingers and none produced any instance of digital tissue loss. Phentolamine was not required to reverse the vasoconstriction in any patients. The authors concluded that incidence of finger infarction in elective low-dose epinephrine injection into the hand and finger was likely to be remote, and that therefore hand (finger) surgery could be performed with local anesthesia containing epinephrine [30].

Long-acting local anesthetics have been also found to be safe in hand surgery. Keramidas et al. studied the efficacy and safety of ropivacaine vs. lidocaine in digital nerve block in a prospective study of 70 adult patients. Patients that underwent immediate reconstruction for traumatic injuries of the digits with either ropivacaine or lidocaine had effective pain control during the procedure and no local anesthetic-associated side effects [31].

The tumescent technique injects large volumes of fluid with dilute anesthetic solution into the subcutaneous fat plane to facilitate dissection while providing anesthesia and producing vasoconstriction to reduce bleeding. The tumescent technique was adopted for face lifts by Brody, which he initially described in 1994 [32]. La Trenta has documented that the use of tumescence local anesthesia on face-lift surgery under IV sedation facilitates the subcutaneous dissection, creates a near bloodless surgical field, and decreases the incidence of hematoma formation [33]. Ramon et al. also showed that when high doses of diluted lidocaine with epinephrine (0.33 %, up to 6.3 mg/kg) were used in six prospective female patients undergoing elective face-lift surgery under IV sedation, there were no lidocaine-related side effects recorded [34].

Mesa and Vasconez showed that face lifts and neck lifts can be performed, wide awake, under local anesthesia using the tumescence technique, without the need of general anesthesia, IV sedation, or heavy oral sedation. In a prospective study, 40 patients were enrolled to undergo face lift and neck lift under either local anesthesia or general anesthesia. Both groups of patients received diluted tumescent local anesthesia consisting of 0.25 % lidocaine and 1:400,000 epinephrine buffered with sodium bicarbonate in the surgical field (midface, lower face, and neck). Patients that elected surgery under wide-awake pure local anesthesia underwent the procedure without any intraoperative pain. None of the patients in either group presented clinical signs of lidocaine toxicity postoperatively [35, 36].

Regional anesthesia supplement with sedation for breast surgery, either reconstructive or cosmetic plastic surgery has been successfully, but is an uncommon practice compared with general anesthesia [37, 38].

Thoracic epidural anesthesia has been shown to be effective in intra-op and postoperative pain control in breast augmentation. Lai et al. studied 30 consecutive patients undergoing submuscular breast augmentation under continuous thoracic epidural anesthesia [39]. His study found that all cases were successfully anesthetized, except one case (3 %) that had a partial analgesic effect and required supplemental general anesthesia. Perioperative complications included transient shivering (33 %), stuffy nose (20 %), nausea (7 %), and shortness of breath (13 %). These symptoms were alleviated after reassurance or light sedation and oxygen inhalation. Immediate postoperative pain of the operative site was effectively controlled by injection of local anesthetics through the epidural catheter. There were no serious side effects associated with this type of regional anesthesia for breast augmentation [39].

Paravertebral nerve bock (PVD ) for breast augmentation has also been shown to be successful. Gardiner et al. evaluated the safety and efficacy of PVB (ropivacaine ) compared with surgical field local anesthesia infiltration for pain control in breast augmentation patients. He found that PVB with ropivacaine is superior to direct surgical infiltration of ropivacaine for bilateral breast augmentation in same-day surgery [40].

Regional anesthesia without IV sedation or general anesthesia, has also been successfully used in breast augmentation [41]. Shimizu et al. evaluated the efficacy and safety of combined intercostal nerve block and tumescent anesthesia (without IV sedation) for breast augmentation in 35 prospective patients. In his study intercostal nerves innervating the T-3 to T-6 regions, were anesthetized using 0.5 % bupivacaine . Tumescent solutions consisting of lidocaine , epinephrine , and saline were injected around the mammary gland. Breast augmentation was conducted using silicone implants. The majority of patients (31/35) reported no pain during the procedure. No patient experienced pneumothorax or toxicity of local anesthetics [42].

Most toxic reactions of local and regional anesthesia involve the central nervous system. Initially, there is an excitatory phase manifesting as muscle twitching, first in the face and distal extremities, that progress to tremors and ultimately to generalized tonic–clonic convulsion. As the anesthetic levels in the CNS rise, a depressive phase ensues, evidenced by drowsiness, unconsciousness, and respiratory arrest [44].

Kairaluoma et al. reported the case of CNS toxicity after a single-injection paravertebral block (SPVP) with 0.5 % bupivacaine for breast surgery [45]. The patient developed convulsions after an SPVB without losing consciousness, which was aborted by a small dose of a benzodiazepine; the author suggested the adverse event was most likely caused by an accidental intravascular injection of part of the local anesthetic .

Bupivacaine, a long-acting local anesthetic, is known for having cardiotoxic effects when compared with short-acting local anesthetics like lidocaine [46]. Sudden cardiovascular collapse (ventricular fibrillation or ventricular· tachycardia, cardiac asystole, or complete heart block with P waves only) that most of the time it is refractory to resuscitative measures has occurred almost immediately after rapid intravascular injection of the local anesthetic agent [46, 47].

Ropivacaine , a long-acting local anesthetic, is known to be less cardiotoxic than bupivacaine [48]. Complications about the use of ropivacaine and bupivacaine in plastic surgery are scarce. Fayman et al. compared the use of bupivacaine and ropivacaine for infiltration anesthesia for bilateral breast surgery. In his study he found that women undergoing either breast reduction or submuscular breast augmentation that underwent infiltration with either bupivacaine or ropivacaine for postoperative pain control did not present complications associated with the use of either local anesthetic [49]. Additionally, in terms of analgesia, they found that overall analgesia achieved with bupivacaine and ropivacaine infiltrations was not statistically different.

A prospective double-blind study was conducted to compare the analgesic properties of levobupivacaine and ropivacaine in a bilaterally symmetrical mastopexy model, which demonstrated that both anesthetics provided satisfactory analgesia for at least 10 h, and none was associated with local anesthetic-related toxicity [50].

Cardiovascular collapse from accidental local anesthetic toxicity is a rare but catastrophic complication of regional anesthesia. The long-acting amide local anesthetics bupivacaine , levobupivacaine, and ropivacaine have differential cardiac toxicity, but all are capable of causing death with accidental overdose [51]. Bupivacaine, levobupivacaine, and ropivacaine are three long-acting amide-based local anesthetics most commonly used in clinical practice.

Of all the amide local anesthetics, bupivacaine exhibits the most cardiotoxicity, which is often the result of a sudden increase of its concentration in the plasma. There is increasing evidence in the anesthesia literature supporting the use of lipid therapy to treat bupivacaine- and ropivacaine -induced toxicity after failure of established resuscitation measures [52]. However, published reports regarding local anesthetic-induced cardiac collapse in esthetic surgery are rare.

Overall, available data suggest that although systemic toxic reactions and cardiotoxicity to long-acting local anesthetics such as bupivacaine , ropivacaine , and levobupivacaine remain significant risks, these problems appear to have evolved to a level where they are comparable to other significant risks of regional techniques, especially in plastic surgery [43].

Major arteries and sizable arteries and arterioles could be punctured while injecting local or regional anesthesia for plastic surgery. Knowledge of the vascular anatomy of the area treated is paramount to avoid accidental vascular complications. The overall incidence of inadvertent vascular puncture and hematoma formation after paravertebral nerve blockade is 6.8 % and 2.4 %, respectively [53]. For local anesthesia administration the data is scarce.

In plastic surgery, the incidence of vascular complications secondary to local or regional anesthesia is very low. In general, the incidence of a meta-analysis of randomized controlled trials about the efficacy and safety of paravertebral blocks in breast surgery by Schnabel et al. showed that none of the trials evaluated reported any patients with vascular puncture or nerve damage [54].

Horner syndrome , the development of the classic triad of miosis, partial ptosis, and loss of hemifacial sweating (anhidrosis) secondary to the blockade of the sympathetic pathways that supply to the eye has been reported during local anesthesia administration in plastic surgery. Schnabel et al. in a meta-analysis of fifteen randomized controlled trials (published between 1999 and 2009) found the incidence of Horner’s syndrome after paravertebral blocks in breast surgery was present but low [54]. In a trial testing of single-injection paravertebral block (SPVB) for breast surgery, only one developed Horner’s syndrome. In another randomize trial for multiple-injection paravertebral nerve block (MPVB ) for breast surgery, 11 patients developed Horner’s syndrome [55]. Burlacu and Buggy also reported a case of Horner’s syndrome in breast plastic surgery. A patient undergoing left mastectomy and immediate latissimus dorsi breast reconstruction under combined paravertebral block and general anesthesia developed left-sided Horner syndrome postoperatively [56].