Jeffrey M. Kenkel

Thromboembolic Risk Assessment and the Efficacy of Enoxaparin Prophylaxis in Excisional Body Contouring Surgery

Background: There is a paucity of evidence within the plastic surgery literature concerning risk stratification and management of patients with respect to thromboembolic disease. A retrospective chart review was conducted to examine whether the Davison-Caprini risk-assessment model could stratify patients undergoing excisional body contouring surgery, allowing prophylaxis to be managed in an evidence-based manner. Methods: Three hundred sixty excisional body contouring patients at the University of Texas Southwestern Medical Center in Dallas, Texas, under the senior authors’ (J.M.K. and R.J.R.) care were reviewed. Patients were stratified into groups according to the risk-assessment model and into groups based on procedure. Patient characteristics were investigated for their effects on thromboembolic risk. Complications of enoxaparin administration were analyzed. The data were analyzed using appropriate statistical procedures. Results: The highest risk patients had a significantly increased rate of venous thromboembolism when compared with lower risk patients. Body mass index greater than 30 and hormone therapy use were associated with a significantly increased venous thromboembolism rate. Enoxaparin administration was associated with a statistically significant decrease in deep venous thrombosis in circumferential abdominoplasty patients. Enoxaparin administration was associated with higher bleeding rates. Conclusions: Low-molecular-weight heparin may affect the incidence of postoperative thrombotic complications in some surgical populations. In this study, patients who scored greater than four risk factors were at significant risk for venous thromboembolism. Enoxaparin significantly decreased deep venous thrombosis risk in patients undergoing circumferential abdominoplasty. This demonstrates the need for a multicenter, prospective, randomized study to examine various thromboembolic therapies and associated possible complications in these patients.

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.

early Results of Vermilion Lip Augmentation Using Acellular Allogeneic Dermis: An Adjunct in Facial Rejuvenation

The definitive approach to lip augmentation has yet to be defined. Herein is described a technique using acellular allogeneic dermal grafts that is easy, effective, and reproducible. Our results over the past 2 years include 47 patients (94 grafts). Three grafts to the upper lip have exhibited significant resorption, which warranted further augmentation. Early in the series, one graft was malpositioned too superiorly along the vermilion-cutaneous border. There have been no cases of infection, hematoma, or graft exposure. The overall complication rate was 4 percent (4 of 94). Our early results by using acellular allogeneic dermal grafts for lip augmentation are encouraging. Further studies are under way to better objectively define long-term results.

Etiology, prevention, and treatment of dermal filler complications.

The availability of dermal fillers for multiple cosmetic indications has led to a dramatic increase in their application. Although fillers are generally regarded as safe tools for soft tissue augmentation, complications can occur. Therefore, to describe and review the complications associated with the currently-available dermal filling agents, the authors conducted a literature review in peer-reviewed journals and present the reported complication rates. They also describe current strategies to avoid, diagnose, and manage complications if they do occur.

Perioperative versus postoperative celecoxib on patient outcomes after major plastic surgery procedures.

BACKGROUND: Controversy continues to surround the use of cyclooxygenase (COX)-2 inhibitors in the perioperative period. We designed this randomized, double-blind, placebo-controlled study to examine the hypothesis that administration of celecoxib preoperatively or postoperatively and for 3 days after major plastic surgery would improve pain control and clinically important patient outcomes. Another objective of the study was to determine whether perioperative administration of celecoxib offered any advantages over postoperative administration alone. METHODS: One hundred and twenty healthy consenting patients undergoing major plastic surgery (e.g., breast augmentation, abdominoplasty procedures) using a standardized general anesthetic technique were randomized to one of three treatment groups: 1) control group (n = 40) received two placebos orally before and after surgery, as well as one placebo BID for 3 days after surgery; 2) postoperative group (n = 40) received two placebos before surgery and 2 celecoxib 200 mg po after surgery, followed by one celecoxib 200 mg po BID on postoperative day #1, #2 and #3; and 3) perioperative group (n = 40) received 2 celecoxib 200 mg po 30–90 min before surgery, and two placebos after surgery, followed by one celecoxib 200 mg po BID on postoperative day #1, #2, and #3. Pain scores, the need for rescue analgesics, and side effects were recorded at specific time intervals in the postoperative period. Follow-up evaluations were performed at 24, 48, 72 h, and 7 days after surgery to assess postdischarge pain, analgesic requirements, return of bowel function, resumption of normal daily activities, quality of recovery, as well as patient satisfaction with pain management. RESULTS: Compared with the control group, the two celecoxib groups had similar significant reductions in postoperative pain and need for opioid analgesics during the first three postoperative days (P < 0.01). Patients recovered bowel function 1 day earlier and resumed normal activities 2 days earlier in the celecoxib groups. In addition, patient satisfaction with pain management and quality of recovery were significantly improved in the celecoxib (versus control) groups (P < 0.05). CONCLUSION: Celecoxib (400 mg po) administered on the day of surgery and for 3 days postoperatively is effective in improving postoperative pain management, as well as the speed and quality of recovery after major plastic surgery. However, perioperative administration offers no advantages over simply giving the drug after surgery.

Effect of low-level laser therapy on abdominal adipocytes before lipoplasty procedures.

Low-level laser therapy is a new subspecialty for the medical application of lasers that provides therapeutic rather than surgical outcomes for many medical indications. Recently, low-level laser therapy was reported to “liquefy” or release stored fat in adipocytes by the opening of specialized yet not identified cell membrane–associated pores after a brief treatment. Currently, low-level laser therapy is a U.S. Food and Drug Administration–approved technology for improving pain alleviation. To explore these data further, a series of in vitro studies on human preadipocytes and institutional animal care and use committee–approved protocols in a porcine Yucatan model and an institutional review board–approved clinical study were performed. Using a 635-nm low-level laser of 1.0 J/cm2 supplied to the authors by the vendor, these studies were designed to determine whether alteration in adipocyte structure or function was modulated after low-level laser therapy. Cultured human preadipocytes after 60 minutes of laser therapy did not change appearance compared with nonirradiated control cells. In the porcine model, low-level laser therapy (30 minutes) was compared with traditional lipoplasty (suction-assisted lipoplasty) and ultrasound-assisted lipoplasty. From histologic and scanning electron microscopic evaluations of the lipoaspirates, no differences were observed between low-level laser therapy–derived and suction-assisted lipoplasty–derived specimens. Using exposure times of 0, 15, 30, and 60 minutes in the presence or absence of superwet wetting solution and in the absence of lipoplasty, total energy values of 0.9 mW were delivered to tissue samples at three increasing depths from each experimental site. No histologic tissue changes or specifically in adipocyte structure were observed at any depth with the longest low-level laser therapy (60 minutes with superwet fluid). Three subjects undergoing large-volume lipoplasty were exposed to superwet wetting fluid infiltration 14 minutes before and 12 minutes after, according to vendor instructions. Tissue samples from infiltrated areas were collected before suction-assisted lipoplasty and lipoaspirates from suction-assisted lipoplasty. No consistent observations of adipocyte disruptions were observed in the histologic or scanning electron microscopy photographs. These data do not support the belief that low-level laser therapy treatment before lipoplasty procedures disrupts tissue adipocyte structure.

An analysis of silicone gel-filled breast implants: Diagnosis and failure rates

&NA; This retrospective review analyzed 180 women who underwent explantation of 357 silicone gel‐filled breast implants from September of 1991 to January of 1995. Implant status, including shell integrity and implantation times, was determined at the time of explantation. The age range of the patients was 25 to 75 years, with a mean age of 47 years. The age of the implants ranged from 0.5 to 24 years, with a mean age of 10.5 years. Of the 292 implants with known and documented integrity status, there were 102 intact, 76 unruptured with signs of leakage, and 114 ruptured. The frequency of implant rupture significantly increased with implant age. The average age of rupture was 13.4 years. The average age of signs of leakage was 10.1 years. There were no significant differences in failure rates among the implant types of four manufacturers. Analysis of both mammography and magnetic resonance imaging (MRI) as diagnostic modalities for differentiating intact implants, implant leakage, and implant rupture was performed. Standard mammography was less reliable in diagnosing implant leakage or rupture (sensitivity, 55 percent; specificity, 69 percent) than MRI (sensitivity, 72 percent; specificity, 82 percent). In conclusion, implant rupture occurred at a significantly increasing rate with implant age (10 to 15 years). These findings were independent of implant type or manufacturer. Mammography alone is a below‐average diagnostic tool for detecting leakage or rupture, whereas MRI is a more accurate modality. (Plast. Reconstr. Surg. 102: 2304, 1998.)

Can fractional lasers enhance transdermal absorption of topical lidocaine in an in vivo animal model

It has been shown in vitro that pretreatment of skin with fractional lasers enhances transdermal delivery of drugs. The aim of this study is to demonstrate in vivo firstly that laser enhances transdermal drug absorption and secondly that this can be manipulated by altering laser settings.

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 Impact of Operative Time on Complications After Plastic Surgery: A Multivariate Regression Analysis of 1753 Cases

BACKGROUND Little evidence within plastic surgery literature supports the precept that longer operative times lead to greater morbidity. OBJECTIVE The authors investigate surgery duration as a determinant of morbidity, with the goal of defining a clinically relevant time for increased risk. METHODS A retrospective chart review was conducted of patients who underwent a broad range of complex plastic surgical procedures (n = 1801 procedures) at UT Southwestern Medical Center in Dallas, Texas, from January 1, 2008 to January 31, 2012. Adjusting for possible confounders, multivariate logistic regression assessed surgery duration as an independent predictor of morbidity. To define a cutoff for increased risk, incidence of complications was compared among quintiles of surgery duration. Stratification by type of surgery controlled for procedural complexity. RESULTS A total of 1753 cases were included in multivariate analyses with an overall complication rate of 27.8%. Most operations were combined (75.8%), averaging 4.9 concurrent procedures. Each hour increase in surgery duration was associated with a 21% rise in odds of morbidity (P < .0001). Compared with the first quintile of operative time (<2.0 hours), there was no change in complications until after 3.1 hours of surgery (odds ratio, 1.6; P = .017), with progressively greater odds increases of 3.1 times after 4.5 hours (P < .0001) and 4.7 times after 6.8 hours (P < .0001). When stratified by type of surgery, longer operations continued to be associated with greater morbidity. CONCLUSIONS Surgery duration is an independent predictor of complications, with a significantly increased risk above 3 hours. Although procedural complexity undoubtedly affects morbidity, operative time should factor into surgical decision making.