Koichiro Oki

Vascular tissue engineering and vascularized 3D tissue regeneration

Vascularized tissue regeneration has a great deal of potential in clinical medicine. Appropriate 3D tissue regeneration that yields tissue with the desired function and shape requires both growth signals and vascularization. In this paper, we discuss vascularized tissue regeneration using various vessel systems: artificial vessel, autologous vascular graft, autologous vascular bundle transfer and tissue engineered vessel. Vascularized 3D tissue regeneration will require a great deal of additional research before it can be applied to clinical situations. Several promising studies of vascularized tissue regeneration have been reported. However, additional studies into the maturation of neovascularization, the development of effective biomaterial, and the possibility of using stem cells will be needed before these techniques can be used in the clinical situation.

The inferior labial artery island flap

The Abbe flap procedure has typically been indicated in cases of tissue defects of the upper lip after injury or tumour excision. However, this method requires two-stage reconstruction. In this report, we describe for the first time a novel one-stage reconstruction method using the inferior labial artery island flap. A 54-year-old man presented with a left upper lip defect and a scar contracture between the upper lip and the left cheek. We planned to reconstruct the lip defect using the inferior labial artery island flap. The inferior labial artery island flap was harvested with a vascular pedicle, and the vascular pedicle was returned through the inside of the flap. The flap survived completely, and liquid leakage from the lip and the appearance of the injured area were clearly improved. For this new technique, we converted the inferior labial flap to a vascular pedicled island flap, which increased its flexibility. This long vascular pedicle could be returned through the inside of the flap. Thus, this flap appears to be ideal for one-stage reconstructions of full-thickness upper lip defects.

Fixation of intracapsular fractures of the condylar head with bioabsorbable screws

A newly-developed fixation technique using bioabsorbable screws gave satisfactory results in fractures of the condylar head. The fracture lines ran obliquely (craniolateral to mediocaudal) on three-dimensional computed tomography. Two bioabsorbable screws were positioned vertically to the fracture lines. This technique is useful despite limited access to the condyle.

The Stainless Steel Wire-based Method of Sogawa Effectively Corrects Severe Ingrown Nails.

Summary: Ingrown nails are defined as inflammation of the lateral nail fold that is caused by penetration by the nail plate and associates with pain and/or infection. The pain associated with ingrown nail hampers walking, raises the risk of falls, and decreases the quality of life. The Sogawa method is a novel conservative medical treatment for ingrown nails that is based on stainless steel wire. It was first reported in 2012 by Sogawa, and we have found that it is very effective for ingrown nails, especially in difficult cases. Here, we show the beneficial effects of the Sogawa method in 2 extremely difficult cases where ingrown nails had recurred after partial nail ablation. We found the Sogawa method to be a quick and easy technique that rapidly improves the pain associated with ingrown nails and later produces properly configured nails. Our experience suggests that it is suitable for severe ingrown nails, such as too short ingrown nails and ingrown nails that have strong inflammation and granulation tissue formation. This is significant because it is difficult to treat such cases with conventional conservative methods, which means that the only remaining therapeutic option is surgery. Thus, the Sogawa method is a novel and highly effective ingrown nail treatment that obviates the need for invasive surgical treatment.

Skin perforator freeways and pathways: understanding the role of true and choke anastomoses between perforator angiosomes and their impact on skin flap planning and outcomes.

1. Okada HC, Alleyne B, Varghai K, Kinder K, Guyuron B. Facial changes caused by smoking: A comparison between smoking and nonsmoking identical twins. Plast Reconstr Surg. 2013;132:1085–1092. 2. Goldberg J, Fisher, M. Co-twin control methods. In: Everitt BS, Howell D, eds. Encyclopedia of Statistics in Behavioral Science. New York: Wiley; 2005. 3. Segal NL. Born Together—Reared Apart: The Landmark Minnesota Twin Study. Cambridge, Mass: Harvard University Press; 2013. et al.1 suggest that when perforators with true anastomoses are involved, long flaps can be harvested safely. They also suggested that to improve the success of flap surgery, surgeons should know where the true anastomoses in our bodies are located; their extensive anatomical studies also revealed the locations of a number of these. However, the biological relevance of true anastomoses and the reason why they exist are not discussed in the article. We would like to propose a possible explanation. The three-dimensional structure of living organisms is influenced by various physical factors, including gravity, atmospheric pressure, and water pressure.2 The skin stretches and shrinks to accommodate musculoskeletal growth and movement. The heart beats constantly and blood flows through vessels. Every part of our body, including the skin, is constantly stretching, shrinking, and moving as we perform our daily activities. These constant, seemingly unremarkable mechanical forces, are in fact essential for forming, maintaining, and changing the dynamic structure and functions of our cells, tissues, and organs. “Mechanobiology,”2,3 the study of how cells and tissues sense mechanical forces, seeks to elucidate how they are influenced by the physical microenvironment. Plastic surgeons often use tissue expanders. This has the well-known effect of inducing endothelial cell proliferation and enlarging the blood vessels.4 We speculate that these blood-vessel changes are caused directly by the expander-induced mechanical forces on endothelial cells and indirectly by associated physiologic changes such as hypoxia. This is similar to what occurs during the “delay” of the skin flap. Indeed, Taylor et al. showed in the aforementioned article that the diameters of the choke vessels in “delayed” flaps have dilated to the size of true anastomotic vessels. These observations and the fact that the skin undergoes constant movement, shrinking, and stretching during daily life led us to hypothesize that true anastomoses are most likely to exist in locations that are subjected extensively to these mechanical forces because these forces impose conditions similar to those in skin flap “delay.” Thus, the mechanobiology behind skin perforator location may relate to “natural delay” conditions. Supporting our hypothesis is that Taylor et al.1 found that true anastomoses are located between perforators of the descending branch of the transverse cervical artery and the transverse branch of the circumflex scapular perforator. This area is likely to undergo extensive stretching caused by the movements of the upper extremities. Thus, understanding the mechanobiology behind the location of skin perforators may help flap surgery to be performed in a more natural manner. DOI: 10.1097/PRS.0000000000000139

Sentinel node biopsy in a patient with malignant melanoma of the under back.

In patients with malignant melanoma, the site for lymph node dessection is now determined by the primary site of the tumor according to the standard of UICC. However, sometimes it is difficult to predict accurate lymph node drainage because the tumor occupies two or three lymph node areas, which Sappey called “Watershed” areas, such as the midline of the trunk. We applied the technique of sentinel node biopsy (SNB) using patent blue dye for the patient with malignant melanoma of the under back. It was possible to detect the lymph node drainage flowing not only to the groin area but also to the axillar area. We consider that SNB is one of the effective methods to determine the lymph node drainage of the tumor in so-called “Watershed” areas. [Skin Cancer (Japan) 2002; 17: 31-37]