Avron H. Lipschitz

Autologous Human Fat Grafting: Effect of Harvesting and Preparation Techniques on Adipocyte Graft Survival

Background: Autogenous fat transfer with lipoinjection for soft-tissue augmentation is a commonly used technique without a universally accepted approach. The high percentage and variable amount of fat resorption reduce the clinical efficacy of this procedure and often result in the need for further grafting. The purposes of this study were to evaluate the effect of different harvesting and preparation techniques on human fat tissue viability and to determine fat tissue viability rates among the different fat preparations transplanted into a severe combined immune deficiency mouse model at 3 months. Methods: Using standard liposuction and syringe aspiration, fat was removed from patients (n = 3) undergoing elective body contouring. Tissue was prepared by six different combinations of centrifugation and/or washing the cells with lactated Ringers solution or normal saline. Metabolic activities of fat cell viability were monitored to assess overall cell viability. To analyze viability over 3 months, freshly harvested tissue specimens (minimum n = 5) were prepared by a combination of various procedures (wash, centrifugation, and different solutions) and subsequently injected under the dorsal flank skin of severe combined immune deficiency mice in two experiments. Mice were monitored for 12 weeks and the fat xenografts were removed for mass and histological evaluations. Results: Metabolic analyses showed improved cell viability in tissue specimens undergoing minimal manipulation. No significant differences in fat cell viability, as assessed by graft weight maintenance or histologic evaluations, were observed with regard to harvesting or preparation techniques. Conclusions: Improved viability of freshly harvested but untreated fat specimens may be expected as compared with grafts that have undergone additional manipulations. No unique combination of preparation or harvesting techniques appeared to be more advantageous on transplanted fat grafts at 3 months. This study also demonstrated a reliable animal model for future investigation into examining novel applications for augmenting fat graft survival.

Functional donor site morbidity following latissimus dorsi muscle flap transfer.

The latissimus dorsi flap is highly versatile and reliable, making it a commonly transferred muscle flap. This study evaluated the subjective donor site morbidity, with special attention to activities of daily living. A review of 85 consecutive female patients who underwent latissimus dorsi muscle transfer was performed. Patients were mailed detailed questionnaires concerning cosmesis, use of the shoulder, time to return to work, weakness, and multiple specific activities of daily living. Up to 39% of patients reported at least moderate weakness, 50% experienced back numbness/tightness, and 22% of patients rated their scar as unacceptable. A significant number of patients had difficulty with vigorous activities of daily living (P < 0.05) compared with more sedentary activities. We conclude that latissimus harvest is not totally without postoperative donor site morbidity, and patients should be counseled accordingly prior to flap transfer.

Pharmacokinetics and safety of lidocaine and monoethylglycinexylidide in liposuction: a microdialysis study.

High doses of lidocaine are administered to patients undergoing liposuction. Monoethylglycinexylidide, the active metabolite of lidocaine, is 80 to 90 percent as potent as lidocaine, and its relative toxicity is approximately that of lidocaine. Monoethylglycinexylidide has not previously been measured in studies on lidocaine in liposuction. The aims of this study were to characterize systemic exposure to lidocaine and monoethylglycinexylidide and to measure lidocaine and monoethylglycinexylidide levels within the tissues. Five female volunteers between the ages of 29 and 40 years underwent liposuction. Lidocaine (1577 to 2143 mg, corresponding to 19.9 to 27.6 mg/kg) was infiltrated during the procedure. Levels of lidocaine and monoethylglycinexylidide in blood and lipoaspirate were assessed perioperatively. Tissue lidocaine and monoethylglycinexylidide levels were measured postoperatively using a microdialysis technique in vivo. The peak (maximal) concentration of lidocaine plus monoethylglycinexylidide was 2.2 to 2.7 microg/ml. Time to peak lidocaine plus monoethylglycinexylidide was 8 to 28 hours after infiltration began. Absorbed lidocaine was estimated to be 911 to 1596 mg; therefore, 45 to 93 percent (mean, 64 percent) of the infiltrated dose was ultimately absorbed. Lipoaspirate analysis showed that 9.1 to 10.8 percent (mean, 9.7 percent) of the infiltrated dose was removed during the procedure. Tissue lidocaine levels below 5 microg/ml were demonstrated from 4 to 8 hours postoperatively. The peak lidocaine plus monoethylglycinexylidide concentration was within safe limits in this group of subjects. Time to peak lidocaine plus monoethylglycinexylidide signifies a delayed peak and therefore a longer period of potential lidocaine toxicity than was originally thought. Microdialysis results demonstrated that tissue lidocaine levels may be subtherapeutic within 4 to 8 hours of the procedure. Investigation into factors controlling the resorption of lidocaine during liposuction is warranted in an effort to improve the duration of effect. Furthermore, considering the active metabolite monoethylglycinexylidide, longitudinal studies are necessary to determine whether improving the side effect profile of lidocaine by reducing the dose administered during liposuction may be possible without decreasing the perioperative analgesic effect.

The key to long-term success in liposuction: a guide for plastic surgeons and patients.

Patients need to have realistic expectations for a long-term successful body contour result. There are four key elements for long-term successful improvement in body contour, and the patient is responsible for the first three: exercise, a proper diet, and other positive lifestyle changes; and successful body contouring. An extensive survey requesting information about the procedures, areas of liposuction, lifestyle habits, and satisfaction was mailed to 600 patients who had liposuction surgery performed between 1999 and 2003. One hundred and eight surveys were undeliverable and 209 completed surveys were returned (34.8 percent of 600 mailed surveys and 42.5 percent of 492 delivered surveys). Data were analyzed by a binary logistic regression with backward elimination. Weight gain (versus no weight gain) was used as the dependent variable. The results showed that regardless of whether the patient did or did not gain weight, both groups reported being very satisfied (30 percent and 48 percent, respectively) or satisfied (43 percent and 34 percent, respectively) with their procedure. Among the weight gain patients, 72 percent would still have the procedure again, compared with 82 percent of responders who did not gain weight. When asked if they would recommend the procedure to family or friends, 90 percent of responders who did not gain weight would recommend the procedure whereas only 74 percent of responders who did gain weight would recommend the procedure (p < 0.001). Among those patients who gained weight, only 29 percent thought their appearance was excellent or good (compared with 79 percent of those who did not gain weight). Among the 57 percent of patients who did not gain weight, 35 percent report exercising more postoperatively (compared with only 10 percent in the weight gain group, p = 0.002) and 50 percent report eating a healthier diet (22 percent in the weight gain group report eating a healthier diet, p = 0.002). In the weight gain group, 67 percent report no change in their diet regimen and only 17 percent thought their productivity increased (compared with 25 percent among the no weight gain group, p = 0.002). Successful body contouring surgery requires a patient to embrace positive lifestyle habits. The results of this survey have been used to create a quantitative decision-making framework or a “road map” for patients and plastic surgeons to use for navigating toward successful long-term results.

Pharmacokinetics and safety of epinephrine use in liposuction

Patients are routinely exposed to high-dose epinephrine infiltration during large-volume liposuction. Because of the serious cardiovascular side-effect profile of catecholamine overdose, the authors examined the safety of larger-volume liposuction by assessing epinephrine pharmacokinetics. Five female volunteers with American Society of Anesthesiologists physical status of I or II, aged 29 to 40 years and weighing 75.9 to 95 kg, underwent liposuction. The wetting solution contained 7.3 mg (SEM, 0.7 mg) of epinephrine, corresponding to 0.09 mg/kg (0.04 mg/kg). Total plasma epinephrine and norepinephrine concentrations were assessed by high-performance liquid chromatography. Approximate exogenous epinephrine absorption was calculated after correction for estimated endogenous epinephrine production. Pharmacokinetic assessments were performed using standard equations. The total plasma epinephrine peak occurred at the final intraoperative reading (5 hours after induction) and was 323 pg/ml (24.8 pg/ml), three to four times maximum baseline resting levels. The norepinephrine level was slightly elevated throughout the study period, with a reversal of the normal epinephrine/norepinephrine ratio (<0.5:1) demonstrated intraoperatively (>5:1). Estimated time to peak exogenous epinephrine level ranged from 1 to 4 hours from the start of infiltration. Area under the plasma concentration versus time curve was approximately 2089 to 2610 pg·hour/ml. Peak exogenous epinephrine concentration was estimated to be 286 to 335 pg/ml. Clearance was 764,508 ml/hour and volume of distribution was 0.4 liter/kg (0.006 liter/kg). Total absorbed epinephrine was estimated, 1.8 mg to 2.2 mg, equivalent to 25 to 32 percent of the infiltrated dose. The reversal of the normal epinephrine/norepinephrine ratio and the fact that norepinephrine levels were within normal range implied that the majority of plasma epinephrine measured was exogenously infiltrated and not endogenously synthesized. On the basis of these observations, pharmacokinetic analyses were performed. Although unequivocal toxic epinephrine levels were not demonstrated, epinephrine peaks were three to four times the maximum observed in normal resting patients. Peak levels were comparable to those observed during major physiologic stresses, such as exercising to exhaustion, open abdominal surgery, or cross-clamping the aorta during surgical repair. Furthermore, epinephrine has been associated with myocardial infarction, arrhythmias, and fatal asystole in susceptible patients at these levels. Patients should be carefully screened for clinical evidence of hemodynamic and cardiac pathology before larger-volume liposuction is undertaken, as it may result in unnecessary high risk for patients who have preexisting cardiovascular disorders. Healthy American Society of Anesthesiologists physical status I or II patients should have sufficient cardiac reserve to tolerate these catecholamine levels.

Efficacy of Lidocaine for Pain Control in Subcutaneous Infiltration During Liposuction

BACKGROUND Liposuction remains the most commonly performed aesthetic surgical procedure in the United States. Preoperative infiltration of the subcutaneous tissues with a wetting solution has become standard. These solutions typically contain some amount of lidocaine for pain control. High doses of lidocaine have been demonstrated to be safe, but large amounts of this cardioactive agent during elective cosmetic procedures may be unnecessary. OBJECTIVE A study was designed to examine the effects of wetting solutions with lower concentrations of lidocaine on perioperative pain. METHODS Seventeen patients were prospectively randomized to subcutaneous infiltration with one of 3 different lidocaine concentrations: 10 mg/kg, 20 mg/kg, or 30 mg/kg. Intra- and postoperative lidocaine and monoethylglycinexylidide (MEGX) plasma concentrations were measured and the total intraoperative inhalation gas requirements and minimum alveolar concentrations were recorded. Postoperative pain medication requirements were recorded and morphine equivalents were calculated. Patient pain level was subjectively assessed by using a visual analog pain scale. RESULTS There was no difference in the intraoperative lidocaine or MEGX concentrations between any of the 3 groups. There was also no statistical difference between the 3 groups when comparing intraoperative inhalational gas requirement, postoperative morphine equivalence requirements, or subjective pain using the visual analog scale. CONCLUSIONS Decreasing concentrations of lidocaine in infiltrative wetting solutions did not significantly affect intraoperative anesthesia requirements or postoperative pain with liposuction. Lower concentrations of lidocaine can effectively be used, use of any lidocaine may be unnecessary. Future investigations may examine whether total elimination of lidocaine yields similar results in terms of anesthesia requirements and postoperative pain.

Electrolyte and plasma enzyme analyses during large-volume liposuction.

Substantial fluid shifts occur during liposuction as wetting solution is infiltrated subcutaneously and fat is evacuated, causing potential electrolyte imbalances. In the porcine model for large-volume liposuction, plasma aspartate aminotransferase and alanine transaminase levels were elevated following liposuction. These results raised concerns for possible mechanical injury and/or lidocaine-induced hepatocellular toxicity in a clinical setting. The first objective of this human model study was to explore the effect of the liposuction procedure on electrolyte balance. The second objective was to determine whether elevated plasma aminotransferase levels were observed subsequent to large-volume liposuction. Five female volunteers underwent three-stage, ultrasound-assisted liposuction. Blood samples were collected perioperatively. Plasma levels of sodium, potassium, venous carbon dioxide, blood urea nitrogen, chloride, and creatinine were determined. Liver function analyte levels were measured, including albumin, total protein, aspartate aminotransferase, and alanine transaminase, alkaline phosphatase, gamma-glutamyl transpeptidase, and total bilirubin. To further define intracellular enzyme release, creatine kinase levels were measured. Mild hyponatremia was evident postoperatively (134 to 136 mmol/liter) in four patients. Hypokalemia was evident intraoperatively in all subjects (mean ± SEM; 3.3 ± 0.16 mmol/liter; range, 3.0 to 3.4 mmol/liter). Hypoalbuminemia and hypoproteinemia were observed throughout the study (baseline: 2.9 ± 0.2 g/dl; range, 2.6 to 3.5 g/dl), decreasing to 10 to 40 percent 24 hours postoperatively (2.0 ± 0.2 g/dl; range, 1.7 to 2.1 g/dl). Aspartate aminotransferase, alanine transaminase, and creatine kinase levels were significantly elevated after the procedure (190 ± 47.1 U/liter, 50 ± 7.7 U/liter, and 11,219 ± 2556.7 U/liter, respectively) (p < 0.01). Release of antidiuretic hormone and even mildly hypotonic intravenous fluid infiltration have long been known to cause hyponatremia postoperatively. Intraoperative hypokalemia is associated with hypocarbia and respiratory alkalosis and the elevated epinephrine levels observed in the concurrent study. Factors having the greatest initial impact on diminished serum albumin and protein levels postoperatively are redistribution and hemodilution. Subsequent diminished viscosity may significantly affect postoperative hemodynamics. Elevated aspartate aminotransferase, alanine transaminase, and creatine kinase levels are associated with skeletal muscle injury, adipocyte lysis, and/or hepatic damage. Therefore, tissue injury is associated with large-volume liposuction as observed in several cellularly released enzymes. Future clinical studies are required to determine the degree of injury and specific tissues that are damaged or sensitive to mechanical trauma and/or drugs used in large-volume liposuction.

Platelet gel sealant use in rhytidectomy

Background: A prospective study was used to evaluate the efficacy of a commercially available platelet gel product as a sealant to decrease postsurgical drain fluid rates and volumes in patients who have undergone rhytidectomy procedures. Quantitative assessments of postoperative drain fluid outputs were compared in subjects who did and did not receive platelet gel treatment. Methods: Autologous platelet concentrate was prepared from each subject (n = 19), combined with bovine thrombin to form a platelet gel, and applied during the rhytidectomy procedure. Surgical drains were placed and effluent was collected postoperatively at 8-hour intervals for 24 hours and the volumes were recorded. A retrospective examination of surgical drain output over time in subjects (n = 14) who did not receive platelet gel treatment was performed; this group served as the control group. Results: Subjects who received the platelet gel sealant treatment had significantly decreased surgical drain fluid levels over 24 hours [109 ± 8.5 ml (mean ± SEM)] compared with subjects who did not receive the platelet gel sealant (78 ± 7.5 ml) (p < 0.02). From 0 to 8 hours postoperatively, platelet gel–treated subjects had a mean 35 percent decrease in fluid levels compared with the controls (p < 0.03). No difference in surgical drain outputs was observed from 8 to 16 hours between the two experimental groups. From 16 to 24 hours, the control group had increased mean fluid levels (20 percent) and the platelet gel sealant group output levels decreased (50 percent). Conclusions: Platelet gel sealant treatment was associated with decreased surgical fluid drain output in the first 24 hours postoperatively.