Katsuyuki Arai

The deep inferior epigastric artery free skin flap: anatomic study and clinical application.

We carried out an anatomic study to create the efficient surgical technique of elevating the inferior epigastric artery free skin flap. The deep inferior epigastric artery bifurcates into the lateral and medial branches. The former usually is larger in diameter and has many skin perforators slightly lateral to the midline of musculature. When a vascular pedicle skin flap is lifted without attaching the rectus abdominis muscle or its anterior sheath, it seems more efficient if the flap uses the skin perforator belonging to the lateral branch. This is so because entry of the inferior epigastric artery is from the lateral side of the rectus abdominis muscle and the lateral branch runs slightly lateral to the midline of the musculature and parallel to the run of the muscular fibers. This would be easier technically and would minimize the damage to the muscle when detaching the lateral branch.

Molecular basis for tissue expansion : Clinical implications for the surgeon

A wide variety of tissue expansion techniques have been used for breast reconstruction, craniofacial surgery, and burn care in plastic reconstructive surgery. However, the basic mechanism by which skin and surrounding tissue respond to mechanical expansion remains unclear. Recent studies have revealed the biomechanical aspects of cells subjected to strain and various factors involved in the stretch-induced signal transduction pathway. In this regard, we have reported previously that mechanical force increases keratinocyte growth and protein synthesis and alters cell morphology. The mechanism by which strain causes an enhancement of cellular growth appears to be a network of several integrated cascades, implicating growth factors, cytoskeleton, and the protein kinase family. Recently, additional evidence has accumulated that mechanical strain stimulates signal transduction pathways that could trigger a series of cascades eventually leading to a new skin production. For example, we have evidence suggesting a key role for protein kinase C (PKC) in mechanosignaling as PKC is activated and translocated in keratinocytes subjected to strain in an isoform-specific manner. In this report, molecular mechanisms leading to enhancement of skin surface area are reviewed, and possible future applications are discussed.

Umbilical reconstruction using a cone-shaped flap

We have performed new umbilical reconstruction with good results in 9 patients using the procedure of forming a circular cone with a flap that is anchored onto the abdominal wall. Our procedure uses a single flap or brings two flaps together, to form a three-dimensional structure with a single or double suture line, so that the umbilicus will retain its depth over a long period of time.

Use of recovery-enhanced thermography to localize cutaneous perforators.

Recovery-enhanced thermography implies the scanning, after cooling, of the skin surface with ice water for several seconds. Using this method, cutaneous perforators were clearly identified in constant distributions on the trunks of 12 healthy volunteers. Clinically, preoperative recovery-enhanced thermography is useful for the design of perforator-based flaps. We describe this method in detail and demonstrate its reliability with successful clinical cases.

A case of giant cell tumor of the parotid gland.

In this study, we report a recent patient with a giant cell tumor located in the parotid gland. This condition appears to be very rare; there have been only a few reports of similar patients. The origin of the tumor has remained unclear in previous patients, as well as in our present patient, and awaits further investigation.

Combined paraumbilical perforator skin flap and vascularized pubic bone graft.

A severely depressed deformity of the buccal region was repaired with an osteocutaneous flap based on the deep inferior epigastric vessels. This osteocutaneous flap has not been previously described in the literature. The superior pubic ramus, supplied by pubic branches from the deep inferior epigastric vessels, forms the bony portion of the combined flap. The cutaneous portion is also supplied by the deep inferior epigastric vessels and its thickness can be adjusted. This combination is useful when requiring both a thin flap and a flat bone.

Role of glycosaminoglycan and fibronectin in endothelial cell growth

This study was undertaken to clarify the biological significance of fibronectin and GAG synthesized in human endothelium. The synthesis of GAG and fibronectin was proved morphologically and biochemically in endothelial cells. The conditioned media of fibroblasts and smooth muscle cells have promoted endothelial cell proliferation and production of extracellular matrix in the endothelium. These results suggest that the extracellular matrix which is composed of fibronectin and GAG may play an important role in endothelial cell regeneration.

Silver-stained nucleolar organizer regions in hypertrophic and keloid scars.

Silver-stained nucleolar organizer regions (AgNORs) have been widely used as a marker of cellular activity and proliferation. In a retrospective study, we investigated the potential value of AgNORs in 12 hypertrophic and 24 keloid scar tissues. Ten normal skin tissues served as controls. A standard silver-staining method was used, and the mean AgNOR count of dermal fibroblastic cells in each tissue was determined. In normal skin, the mean AgNOR count of dermal fibroblasts was 1.79+/-0.55, whereas fibroblastic cells in hypertrophic and keloid scars had mean AgNOR counts of 3.18+/-0.56 and 5.10+/-0.97, respectively. There was a statistically significant difference between the mean AgNOR counts of fibroblastic cells from normal skin, hypertrophic scar, and keloid scar [one-factor analysis of variance (ANOVA), p < 0.0001]. Our findings suggest that AgNOR count may be a useful marker for assessment of fibroblastic cell activity in hypertrophic and keloid scars, which may have potential value for histologic and biologic characterization of the two lesions.

Dermal neoformation during skin wound healing as demonstrated using scanning electron microscopy

Little is known about how the structures of connective tissue newly form during the wound-healing process. The authors investigated the repair process of excised skin wounds using alkali water cell maceration scanning electron microscopy. The development of the papillary dermis on the granulation surface proceeded toward the center of the wound, coupled with epidermis migration. No papillary dermis was evident on the granulation surface that had yet to be epithelialized. Finally, a layered structure as observed in normal dermis was reconstructed in the scar tissue. In other words, epidermis, basement membrane, and papillary dermis developed on the granulation surface accompanying epidermal migration, and reticular dermis as the result of maturation of granulation tissue. These findings demonstrate that both the papillary dermis and the reticular dermis develop differently after wounding, and that new papillary dermis and new epidermis develops as if completing “a unit” during the epithelialization process. The authors denote this unit the epithelialization unit.

Use of microvascular island pedicle flaps for facial tissue defects

Microsurgical dissection was used with satisfactory results to construct a microvascular island pedicle flap for the coverage of small facial tissue defects in 3 patients. The advantages of this flap include improved survival, excellent mobility, and elimination of cosmetic problems usually encountered with rotation or distant flaps.