A randomized, evaluator-blinded, two-center study of the safety and effect of volume on the diffusion and efficacy of botulinum toxin type A in the treatment of lateral orbital rhytides.

BACKGROUND: There has been considerable discussion about the effect of the degree of dilution of botulinum toxin (BTX) but very few scientific studies. OBJECTIVE: The objective was to observe as to whether a fivefold difference in concentration of BTX solution would produce a difference in clinical effect or duration of effect. METHODS AND MATERIALS: Twenty individuals were enrolled at two sites and a within-subject paired-comparison study was performed on the lateral orbital area with a single injection of 5 U of BTX (BOTOX Cosmetic, Allergan Inc., Irvine, CA). The results were assessed both clinically and using a computer-assisted estimation of the degree of wrinkling. RESULTS: No statistically significant differences were observed between the two sides. CONCLUSIONS: This is a small study and it may be that dilution does affect BTX result. We were, however, unable to detect any difference in this study, which suggests that the degree of dilution, at least within a fivefold margin, has only a small effect on the results of BTX injection in the lateral orbital area.

Clinical evaluation of enhanced nonablative skin rejuvenation using a combination of a 532 and a 1,064 nm laser.

BACKGROUND AND OBJECTIVES: Improvements in the physical signs of photoaging can be achieved by non-invasive laser resurfacing procedures. To evaluate the effectiveness and safety of the Nd:YAG 1,064 nm and KTP 532 nm lasers for non-invasive skin rejuvenation. STUDY DESIGN/PATIENTS AND METHODS: Subjects requesting non-invasive skin rejuvenation underwent two treatments with the 532 nm laser to one side of the face and with both lasers to the other side, followed by three treatments with the 1,064 nm laser to both sides. Skin characteristics were evaluated before, during, and up to 4 months after treatment. RESULTS: A >25% improvement in overall skin condition was observed for >30% of subjects at the 1 month follow-up and >40% of subjects at the 4 month follow-up. The greatest improvements were observed for visual dryness, roughness, and uneven pigmentation. No adverse events were reported. There was a trend for greater improvement in patients who received more 1,064 nm treatments but this was not statistically significant. CONCLUSIONS: The 532 nm KTP and 1,064 nm Nd: YAG lasers can be effectively and safely used for non-invasive skin rejuvenation.

Nonablative laser and light treatments: histology and tissue effects--a review.

BACKGROUND AND OBJECTIVES: Nonablative laser and light treatments have largely replaced ablative laser therapy in clinical use for the improvement of the visible signs of cutaneous photoaging, including rhytides, vascular lesions, and pigmentation. However, the mechanisms underlying the reported clinical efficacy of nonablative treatments are not well-understood. The purpose of this analysis is to critically evaluate what is known about histologic and tissue effects of nonablative laser therapy and suggest future directions for research. STUDY DESIGN/MATERIALS AND METHODS: This is a review of the English language literature pertaining to nonablative laser and light treatments available through MEDline (1995-2002), and unpublished reports presented at major national meetings. Only studies that included harvesting and analysis of tissue samples are included. RESULTS AND CONCLUSIONS: (a) Thermal injury to the dermis in association with epidermal cooling most likely affects the dermal vasculature, which initiates a cascade of inflammatory events that includes fibroblastic proliferation and apparent up-regulation of collagen expression; (b) There is no indication that nonablative treatments are harmful or able to induce skin cancer; (c) It is possible that the horizontally distributed collagen reported after nonablative treatments is a "microscar," an enlarged Grenz sone associated with repetitive photo-induced trauma; (d) Further research is needed to elucidate the biophysical mechanisms underlying nonablative treatment, as well as to distinguish the utility of different wavelengths on epidermal and dermal improvement.

The use of nonablative radiofrequency technology to tighten the lower face and neck.

The ThermaCool TC system is a radiofrequency device capable of delivering higher energy fluences to a greater volume of tissue than nonablative lasers, with no epidermal injury. It has been successful in treating periorbital rhytides and lifting eyebrows. Given these positive finding for treatment of the upper face, the device has been recently applied to rejuvenate and tighten the skin on the lower face and upper neck. This study shows the efficacy and patient satisfaction with this application. Data were compiled over a 6-month period from patients treated with the ThermaCool TC system on the lower face. Up to 3 areas were treated: cheeks, jawline, and upper neck. Treatment parameters and adverse events were recorded and digital photographs taken. Telephone interviews were then conducted after the treatment to assess patient satisfaction. Sixteen patients underwent treatment of the lower face during this period. Eleven of the patients had all three areas (cheeks, jawline, and neck) treated. Two patients had only the cheeks and jawline treated, and 3 patients underwent treatment of the cheeks only. The average level was 14.6 for the cheeks with the average energy of 113.8 joules per pulse. The average treatment level of the jawline was 14.0, with the average energy of 107.0 joules per pulse. The average level was 13.8 for the neck, at the average energy of 99.7 joules per pulse. All patients experienced mild erythema and edema of the treatment areas as expected, and all resolved within 48 hours post-treatment. Fifteen of the 16 patients were available for interview. Ten patients found the results unsatisfactory while five patients were satisfied. Four of 11 (36%) patients who had all 3 areas treated reported satisfactory results, compared to 1 of 4 (25%) of patients who had only 1 or 2 areas treated. The satisfactory group consistently was higher in both dial setting and energy per pulse. Furthermore, the average age of the unsatisfactory group was 58, compared to 51 of the satisfactory group. Photographic analysis of pre- and post-treatment digital images did not yield statistically significant results. Our study adds the growing body of information on this new device. Radiofrequency causes movement of charged particles within the tissue, and the resultant molecular motion generates heat. The heat in turn causes collagen shrinkage and new collagen deposition. Based on our findings, younger patients tend to respond better. This is not surprising, since heat-labile collagen bonds are progressively replaced by irreducible multivalent cross-links as the tissue ages. Second, higher dial settings and corresponding higher energy per pulse correlated with better response. Third, those who had the entire surface area of the face and neck treated tend to do better than those with partial treatment. The data from the study give us critical clues in refining this exciting new technology for cosmetic uses and beyond.