Plasma concentrations of monoethylglycinexylidide during and after breast augmentation

MEGX (monoethylglycinexylidide) is the main metabolite of lidocaine and is 83 percent as potent as an antiarrhythmic drug and with the same toxicity as lidocaine. In this study, plasma levels of MEGX were measured in 10 other wise healthy women during and after breast augmentation. A total dose of 825 to 1,280 mg of lidocaine of 0.2% and 0.5% lidocaine with epinephrine corresponding to 16.3 to 21.8 mg/kg (mean, 18.2 mg/kg) was injected in the spatium between the pectoralis muscle and the mammary gland. The peak plasma concentrations of MEGX varied between 0.40 and 0.99 microg/ml (mean, 0.49 microg/ml) and occurred between 8 and 12 hours (mean, 9.1 hours), postoperatively. In three patients, the concentration of MEGX was still increasing after 12 hours. In comparison, the peak plasma concentrations of lidocaine varied between 0.96 and 3.12 microg/ml (mean, 1.49 microg/ml) and occurred between 4 and 12 hours (mean, 7.3 hours) after the end of the injection. The peak lidocaine + MEGX concentrations varied between 1.45 and 3.58 microg/ml (mean, 2.02 microg/ml) and occurred between 5 and 12 hours (mean, 8.5 hours), postoperatively. These data suggest that MEGX might contribute to lidocaine toxicity when high doses of lidocaine are injected. The substantial interindividual variation strongly indicates that recommendations about maximum safe doses of lidocaine should be made with caution.     

Chronic morphine administration enhances nociceptive sensitivity and local cytokine production after incision

Background

Recent evidence suggests that oxytocin (OT), secreted in the superficial spinal cord dorsal horn by descending axons of paraventricular hypothalamic nucleus (PVN) neurons, produces antinociception and analgesia. The spinal mechanism of OT is, however, still unclear and requires further investigation. We have used patch clamp recording of lamina II neurons in spinal cord slices and immunocytochemistry in order to identify PVN-activated neurons in the superficial layers of the spinal cord and attempted to determine how this neuronal population may lead to OT-mediated antinociception.

Results

We show that OT released during PVN stimulation specifically activates a subpopulation of lamina II glutamatergic interneurons which are localized in the most superficial layers of the dorsal horn of the spinal cord (lamina I-II). This OT-specific stimulation of glutamatergic neurons allows the recruitment of all GABAergic interneurons in lamina II which produces a generalized elevation of local inhibition, a phenomenon which might explain the reduction of incoming Aδ and C primary afferent-mediated sensory messages.

Conclusion

Our results obtained in lamina II of the spinal cord provide the first clear evidence of a specific local neuronal network that is activated by OT release to induce antinociception. This OT-specific pathway might represent a novel and interesting therapeutic target for the management of neuropathic and inflammatory pain.     

Mammaplasty combining vertical and transverse approaches through a vertical incision

An adjustable vertical marking is described for vertical mammaplasty in mild and moderate hypertrophy or ptosis of the breast. A vertical rectangular flap with the pedicle supported at the inframammary fold provides fullness for the upper or the lower pole of the breast. It is fixed over the pectoralis aponeurosis along the upper pole to the base of the pedicle. Length, width, and thickness of the vertical rectangular flap change regarding the extent of breast ptosis and hypertrophy. Two transverse triangular flaps, dissected in the lower pole of the breast, are supported on the inferior half of the vertical pillars at the incision margins. The criss-crossing of the triangular flaps creates a transverse support sling, avoiding the downward displacement of the breast. The vertical flap is applied in conjunction with the triangular flap to attempt to achieve projection and support for the breast with long-term stabilization of the mammary cone. Resection of mammary tissue is performed transversely just above the pedicle of the vertical flap.     

Transumbilical endoscopic breast augmentation: submammary and subpectoral

Endoscopic techniques have recently been applied to aesthetic cosmetic surgery procedures. Endoscopic bilateral augmentation mammaplasty through a transumbilical approach ("TUBA") has recently been advocated as an alternative technique. The purpose of this article is to describe the author's transumbilical technique, to identify procedural limitations and special considerations, and to retrospectively analyze preliminary results. Five hundred thirteen patients (n = 1026 breasts) who underwent submammary transumbilical augmentation from January of 1993 through December of 1998 were evaluated. In 1997, the technique was further developed to permit subpectoral placement of implants; an additional 140 patients (n = 280 breasts) who underwent subpectoral transumbilical augmentation from September of 1997 through February of 1999 will also be presented. Success of the technique was based upon a number of criteria, including completion of the operation without conversion to an inframammary incision or reoperation, normal nipple-areola sensation, absence of hematoma formation, absence of infection, no umbilical scar revision, and patient satisfaction. Complications included hematoma (n = 2 breasts), conversion to inframammary incision (n = 5 breasts), and required secondary corrective procedure (n = 3 breasts). The majority of these complications occurred early in the learning curve. The successful augmentation rate in 1306 breasts was 99.2 percent. Based upon these results, transumbilical endoscopic breast augmentation is believed to be a safe alternative technique with excellent results.