The strength of surgical knots involves a critical interplay between friction and elastoplasticity.

Knots are the weakest link in surgical sutures, serving as mechanical ligatures between filaments. Exceeding their safe operational limits can cause fatal complications. The empirical nature of present guidelines calls for a predictive understanding of the mechanisms underlying knot strength. We identify the primary ingredients dictating the mechanics of surgical sliding knots, highlighting the previously overlooked but critical effect of plasticity and its interplay with friction. The characterization of surgeon-tied knots reveals the relevant ranges of tightness and geometric features. Using model experiments coupled with finite element simulations, we uncover a robust master curve for the target knot strength versus the tying pre-tension, number of throws, and frictional properties. These findings could find applications in the training of surgeons and robotic-assisted surgical devices.

Transverse Facial Artery Perforators: Anatomical, Two- and Three-Dimensional Radiographic Study.

BACKGROUND: Increased anatomical knowledge of skin vascularization, such as the recent description of angiosome and perforasome concepts, has led to important innovations in flap surgery. In this sense, few studies have been performed on face vascularization especially for facial artery perforasomes. The aim of this study was to analyze the number, size, and localization of transverse facial artery perforators and their perfusion area. METHODS: Fourteen hemifaces of fresh adult cadavers from the Department of Anatomy of Lyon University were harvested. Transverse facial artery perforators were identified, dissected, cannulated, and selectively injected with 1 ml of patent blue or contrast solution. Photography, microangiography, and computed tomography were performed. Perforator diameter and localization from the lateral canthus were measured. Exact topography and size of the perforasome were analyzed. RESULTS: Twenty-three transverse facial artery perforators were identified. Mean perforator diameter was 1.01 ± 0.3 mm. Mean perforating site was 31.0 ± 8.0 mm lateral to and 38.7 ± 8.8 mm below the lateral canthus. Mean single perforasome surface area was 25.3 ± 18.34 cm and mean transverse facial artery skin territory was 40.5 ± 9.78 cm. CONCLUSIONS: The transverse facial artery provides at least one perforator that can be accurately localized using a Doppler probe. Clinical applications related to the improved knowledge of transverse facial artery perforators could be as follows: (1) performing a lateral facial skin flap; (2) facial composite allotransplants; (3) face-lift procedures to improve skin perfusion; and (4) prevention of vessel injury in aesthetic procedures such as dermal filler injection or thread-lift techniques.

Indications and Controversies in Lipofilling for Partial Breast Reconstruction.

The treatment of sequelae after conservative breast cancer treatment can be a challenge. Lipomodeling, although controversial in the beginning, is a safe technique that can help in the treatment of these deformities, without an important impact on the imaging surveillance. Depending on the severity of the deformity, one or several sessions of fat transfer can be required. The technique is easy and reproducible, but before obtaining satisfying results with a low complication rate, a learning curve should be completed. The final result is natural, with normal breast consistency, with no additional scars.

Indications and Controversies in Total Breast Reconstruction with Lipomodeling.

Complete breast reconstruction with fat grafting is an appealing technique because it does not add scars or use flaps, is autologous, and has the secondary benefit of liposuction. It is a multiple stage surgery and usually requires balancing of the contralateral breast. After using this technique since 2001, the authors narrowed the indications, the ideal candidate being a patient with small breasts and enough donor sites for up to 4 or 5 lipomodeling sessions. Breast reconstruction with fat grafting alone in total breast reconstruction has very limited indications, because lipomodeling in combination with other autologous reconstruction gives very nice results.

Skin-Reducing Mastectomy in Immediate Reconstruction: How to Limit Complications and Failures.

BACKGROUND: In hypertrophic and/or very ptotic breasts, skin-reducing mastectomy (SRM) is challenging and the risk of complications is high. Few publications have reported the use of an autologous latissimus dorsi flap (ALDF) in this indication. Most studies opt for implant reconstructions, with a high failure rate. OBJECTIVES: We aimed to identify and present the technical refinements that reduce the risk of reconstruction failure in patients with hypertrophic and/or ptotic breasts with breast cancer or at risk of breast cancer after SRM with immediate breast reconstruction (IBR) utilizing an ALDF. METHODS: Our retrospective study, covering a period of 18 years, included a series of 60 patients with hypertrophic and/or ptotic breasts who underwent 67 SRM and IBR procedures utilizing an ALDF. The complications were recorded and the risk factors analyzed. RESULTS: Sixty-seven SRMs were reviewed. Forty-nine procedures were performed with an inverted-T scar technique and 18 with a vertical scar technique. The nipple-areola complex (NAC) was preserved in 10 cases. There were eight (11.9%) cases of minor mastectomy flap necrosis after skin-reducing reconstructions, 16 (23.8%) wound dehiscences, no infections, no breast seromas, and no reconstruction failures. Smoking increased the risk of minor mastectomy flap necrosis (P = 0.048) and wound dehiscence (P = 0.002). Previous radiotherapy was associated with minor mastectomy flap necrosis (P = 0.001). CONCLUSIONS: The use of an ALDF together with technical refinements that preserve the vascular supply of the skin envelope leads to successful IBR with consistently good aesthetic results. Above all, it avoids failure of the reconstruction in very large or ptotic breasts.

The Role of Fat Grafting in Breast Reconstruction.

Breast lipomodeling, or breast fat grafting, is a major development in breast plastic surgery. This technique has a low complication rate, excellent results, and patient acceptance. Radiologic evaluation mostly shows a normal-appearing breast. During breast reconstruction, fat grafting is the ideal complement of the latissimus dorsi flap. Fat grafting for Poland syndrome seems to be a great step and will most likely drastically change the surgical treatment of severe cases. Finally, lipomodeling is a new alternative in the treatment of pectus excavatum, tuberous breasts, and breast asymmetries.

Effective treatment of invasive Aspergillus fumigatus infection using combinations of topical and systemic antifungals in a severely burned patient.

The authors describe an invasive Aspergillus fumigatus deep-burn wound infection in a severely burned patient that was successfully treated with a combination of topical terbinafine and systemic voriconazole antifungal therapy. To our knowledge, this is the first case report describing the effective control of an invasive deep-burn wound infection using this combination.

Autologous keratinocyte suspension in platelet concentrate accelerates and enhances wound healing - a prospective randomized clinical trial on skin graft donor sites: platelet concentrate and keratinocytes on donor sites.

BACKGROUND: Wound healing involves complex mechanisms, which, if properly chaperoned, can enhance patient recovery. The abilities of platelets and keratinocytes may be harnessed in order to stimulate wound healing through the formation of platelet clots, the release of several growth factors and cytokines, and cell proliferation. The aim of the study was to test whether autologous keratinocyte suspensions in platelet concentrate would improve wound healing. The study was conducted at the Lausanne University Hospital, Switzerland in 45 patients, randomized to three different topical treatment groups: standard treatment serving as control, autologous platelet concentrate (PC) and keratinocytes suspended in autologous platelet concentrate (PC + K). Split thickness skin graft donor sites were chosen on the anterolateral thighs of patients undergoing plastic surgery for a variety of defects. Wound healing was assessed by the duration and quality of the healing process. Pain intensity was evaluated at day five. RESULTS: Healing time was reduced from 13.9 ± 0.5 days (mean ± SEM) in the control group to 7.2 ± 0.2 days in the PC group (P < 0.01). An addition of keratinocytes in suspension further reduced the healing time to 5.7 ± 0.2 days. Pain was reduced in both the PC and PC + K groups. Data showed a statistically detectable advantage of using PC + K over PC alone (P < 0.01). CONCLUSION: The results demonstrate the positive contribution of autologous platelets combined with keratinocytes in stimulating wound healing and reducing pain. This strikingly simple approach could have a significant impact on patient care, especially critically burned victims for whom time is of the essence. CLINICAL TRIAL REGISTRY INFORMATION: Protocol Record Identification Number: 132/03Registry URL: http://www.clinicaltrials.gov.