Yoon Kyu Chung

The effect of hyperbaric oxygen on ischemia-reperfusion injury: An experimental study in a rat musculocutaneous flap

Abstarct The effect of hyperbaric oxygen is known to increase survival of ischemic tissue but its mechanism is not fully understood. The purpose of this study was to evaluate the effect of hyperbaric oxygen on a rat musculocutaneous flap versus ischemia–reperfusion injury, focusing on the mechanism involving the expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) of endothelial cells and CD18 of neutrophils. A transverse rectus abdominis musculocutaneous (TRAM) flap (6 × 5 cm) supplied by a single superior epigastric vascular pedicle was elevated in 100 Sprague–Dawley rats. The rats were divided into 4 groups: group 0, sham (n = 10); group I, 4 hours of ischemia followed by reperfusion (n = 30); group II, 4 hours of ischemia and hyperbaric oxygen (100% oxygen, 2.5 atm absolute, during the last 90 minutes of ischemia before reperfusion) followed by reperfusion (n = 30); and group III, 4 hours of ischemia followed by reperfusion and hyperbaric oxygen (100% oxygen, 2.5 atm absolute, after reperfusion for 90 minutes; n = 30). The study consisted of gross examination for flap survival, histology, immunohistochemical staining, myeloperoxidase assay, flow cytometric study of CD18, and Northern blot analysis on ICAM-1 messenger ribonucleic acid expression. Gross measurement of the flap showed increased survival in groups II and III compared with group I (P < 0.05). The leukocytes adherent to the endothelium were counted at 24 hours and on day 5. Group I leukocytes were significantly increased compared with groups II and III (P < 0.05). The myeloperoxidase assay of TRAM flaps at 24 hours revealed a significant increase in group I compared with groups II and III (P < 0.05). The expression of CD18 was similar between groups I, II, and III. Immunohistochemical staining for ICAM-1 and Northern blot analysis on ICAM-1 messenger ribonucleic acid showed decreased expression in groups II and III compared with group I. Throughout the analysis, groups II and III did not show any significant differences. These results suggests that hyperbaric oxygen reduces the accumulation of leukocytes in the TRAM flap, but not enough to prevent adhesion of neutrophils on endothelial cells; ischemia–reperfusion injury increases the expression of CD18 and ICAM-1 and causes increased adhesion of leukocytes on the endothelium; hyperbaric oxygen does not alter the expression of CD18 but decreases the expression of ICAM-1; and the point of application for hyperbaric oxygen, whether applied before or after reperfusion, did not show any differences in outcome. In conclusion, the application of hyperbaric oxygen against ischemia–reperfusion injury increases flap survival and the beneficial effect may be explained by a protective mechanism involving downregulation of ICAM-1 on endothelial cells.

Polymorphisms in the DNA repair gene XRCC1 associated with basal cell carcinoma and squamous cell carcinoma of the skin in a Korean population

DNA in most cells is regularly damaged by endogenous and exogenous mutagens. Unrepaired damage can result in apoptosis or may lead to unregulated cell growth and cancer. Inheritance of genetic variants at one or more loci results in reduced DNA repair capacity. This hospital‐based case‐control study examined whether polymorphisms in the DNA repair gene X‐ray repair cross‐complementing groups 1 (XRCC1) (Arg194Trp[C > T], Arg280His[G > A] and Arg399Gln[G > A]) play a role in susceptibility to skin cancer. We genotyped these polymorphisms for 212 histopathologically confirmed skin cancer cases (n = 114 basal cell carcinoma, n = 98 squamous cell carcinoma) and 207 age‐ and sex‐matched healthy control cases in Korea. We found that individuals with the Arg/Gln and Arg/Gln + Gln/Gln genotypes at XRCC1 Arg399Gln(G > A) had an approximately 2‐fold increased risk of basal cell carcinoma compared to individuals with the Arg/Arg genotype (adjusted odds ratio [AOR] = 2.812, 95% confidence interval [CI] 1.32–5.98, and AOR = 2.324, 95% CI 1.11–4.86). However, we observed that the 194Trp allele of the Arg194Trp(C > T) polymorphism was inversely associated with squamous cell carcinoma risk (Trp/Trp, AOR = 0.06, 95% CI 0.006–0.63). Our data suggest that the Arg194Trp and Arg399Gln polymorphisms may be differentially associated with skin cancer risk. (Cancer Sci 2007; 98: 716–720)

Ipsilateral island fibula transfer for segmental tibial defects : Antegrade and retrograde fashion

&NA; Five patients with segmental tibial defects whose contralateral fibula could not be used as a donor were treated with ipsilateral island fibular transfer in an antegrade or retrograde fashion. Antegrade‐flow pedicled flaps based on the peroneal vessel as in the conventional free flap were used for the proximal or middle one‐third tibial defects, whereas retrograde‐flow pedicled flaps based on the communicating branch between the peroneal and posterior tibial vessels were used for the middle or distal one‐third of the tibia. All patients had one of the following problems: a previously failed free flap, below‐knee amputation of the opposite leg because of open tibia fracture, refusal to use the contralateral sound leg, or poor general condition to endure a lengthy operation. Four of the patients also had an associated fibular fracture on the same leg, which was ultimately used as one of the osteotomy sites. The follow‐up period was from 31 to 48 months. Time to bony union ranged from 4 to 7 months. Time to full weight bearing was from 5 to 9 months after operation. All of the transferred fibulas showed hypertrophy after weight bearing. Nonunion occurred in two cases, which were treated with a long leg cast and cancellous bone graft, respectively. The limb was shorter by an average of 0.5 cm in three cases, longer by 1.1 cm in one case, and in the last case, it was uncheckable because the opposite limb was previously amputated. Limited are of rotation was not a problem. Other disabling complications were not seen. We believe that these methods can be a valuable alternative to the contralateral free fibula flap in certain cases. (Plast. Reconstr. Surg. 101: 375, 1998.)

Single-stage Achilles tendon reconstruction using a composite sensate free flap of dorsalis pedis and tendon strips of the extensor digitorum longus in a complex wound.

The reconstruction of the posterior heel including a wide defect of the Achilles tendon is difficult as a result of complicated infection, deficient soft tissue for coverage, and functional aspects and defects of the tendon itself. As a single-stage procedure, various methods of tendon transfer and tendon graft have been reported along with details of local flaps or island flaps for coverage. With advances in microsurgical techniques and subsequent refinements, several free composite flaps, including tendon, fascia, or nerve, have been used to reconstruct large defects in this area without further damaging the traumatized leg. The authors report such a single-stage reconstruction of a composite Achilles tendon defect using the extensor digitorum longus tendon of the second to fourth toe in combination with a dorsalis pedis flap innervated by the superficial peroneal nerve. The follow-up of this case has proved a satisfactory outcome to date.

The effect of prostaglandin E1 versus ischemia-reperfusion injury of musculocutaneous flaps.

The purpose of this study was twofold. To evaluate whether prostaglandin E1 can increase the survival of the flap, and to determine its function against ischemia-reperfusion injury in musculocutaneous flaps. Thirty-five Sprague-Dawley rats weighing 250 to 350 g were analyzed. The transverse rectus abdominis musculocutaneous flap was used in all rats. The rats were divided into three groups: group 1 (N = 15), the control group with 4-hour ischemic injury and intraflap injection of normal saline followed by reperfusion; group 2 (N = 15), prostaglandin E1 intraflap injection of 1 &mgr;g immediately after ischemic injury and reperfusion 4 hours later; and group 3 (N = 5), the sham-operated group. Analysis consisted of flap skin survival area measurements, immunohistochemical study using anti-intercellular adhesion molecule (anti-ICAM-1) monoclonal antibody, and histological evaluation including endothelium-sticking leukocytes at 24 hours and 5 days after reperfusion. The group treated with prostaglandin E1 showed immunohistochemical findings with decreased expression of ICAM-1 on the surface of the endothelium, and histology showed significant (p < 0.01) reduction of leukocyte adhesion at 24 hours and 5 days after reperfusion. These two factors were considered to play a role against ischemia-reperfusion injury, and led to improved survival of the flap. These results suggest that prostaglandin E1 may increase flap survival and may have a protective mechanism against ischemia-reperfusion injury by decreasing leukocyte-endothelial cell adhesion through decreased expression of ICAM-1.

Sensate sole-to-sole reconstruction using the combined medial plantar and medialis pedis free flap.

The coverage of soft-tissue defects of the sole needs special consideration because of the forces of weight bearing on the reconstruction. A variety of free tissue transfers have been advocated for soft-tissue replacement of the weight-bearing portions. However, there is no doubt that the ideal tissue for resurfacing the sole is the plantar tissue itself. The authors present a case of reconstructing the sole with the combined medial plantar and medialis pedis free flap that involves approximately 70% of the weight-bearing portion. This contralateral, combined fasciocutaneous free flap based on the posterior tibial-medial plantar vascular system is a good alternative in covering extensive sole injuries.

A Retrospective Review of Iatrogenic Skin and Soft Tissue Injuries

Background Even though the quality of medical and surgical care has improved remarkably over time, iatrogenic injuries that require surgical treatment including injuries caused by cast and elastic bandage pressure, extravasation, and dopamine-induced ischemia still frequently occur. The goal of this study was to estimate the incidence and analyze the distribution of iatrogenic injuries referred to our department. Methods A retrospective clinical review was performed from April 2006 to November 2010. In total, 196 patients (116 females and 80 males) were referred to the plastic surgery department for the treatment of iatrogenic injuries. We analyzed the types and anatomic locations of iatrogenic complications, along with therapeutic results. Results An extravasation injury (65 cases, 37.4%) was the most common iatrogenic complication in our study sample, followed by splint-induced skin ulceration, dopamine-induced necrosis, prefabricated pneumatic walking brace-related wounds and elastic bandage-induced wounds. Among these, prefabricated pneumatic walking brace-related complication incidence increased the most during the 5-year study period. Conclusions The awareness of the very common iatrogenic complications and its causes may allow physicians to reduce their occurrence and allow for earlier detection and referral to a plastic surgeon. We believe this is the first study to analyze iatrogenic complications referred to a plastic surgery department in a hospital unit.

Reconstruction of fingertip and stump using a composite graft from the hypothenar region

Finger amputation with bone exposure when replantation is not feasible requires a procedure for closure and padding of the stump. To preserve the length and provide adequate coverage, various flaps are used. A situation may occur in which local flaps are not sufficient and distant flaps are preferred. However, distant flaps often require a two-stage procedure, prolonged immobilization, and skin grafts. Thus, a simpler approach for fingertip or stump reconstruction while maintaining the padding effect of a flap was designed. The composite of glabrous skin and subcutaneous fat provided such padding, was performed in a single stage, and the donor site morbidity was negligible. During a 5-year period from 1996 to September 2002, 15 cases of finger stumps were reconstructed using the hypothenar composite graft. The age of the patients ranged from 1 to 63 years (average, 30 years). The average follow-up was 35 months. The donor sites were closed primarily and there were no marked complications related to this site. The graft showed relatively good contour and color match to the adjacent field, with an average two-point discrimination of 5.7 mm, indicating satisfactory reinnervation. The hypothenar composite graft for reconstruction of finger stumps can provide protective padding, maximal stump length, and minimal donor site morbidity, leading to satisfactory aesthetic and functional recovery.

Zygomatic arch fracture: a new classification and treatment algorithm with epidemiologic analysis.

Abstract Determining the optimal method for zygoma fracture reduction is a common challenge. Numerous methods for treating zygomatic arch fractures have been suggested. However, a substantial gap exists between suggested treatment strategies and real-world practice. A general consensus of classification and treatment guidelines for zygomatic arch reduction has not yet been established. We reviewed our cases and propose a new classification of zygomatic arch fracture and a treatment algorithm for successful reduction based on the injury vectors.

Acellular Dermal Matrix to Treat Full Thickness Skin Defects: Follow-Up Subjective and Objective Skin Quality Assessments

Background There are several options for replacement of the dermal layer in full-thickness skin defects. In this study, we present the surgical outcomes of reconstruction using acellular dermal substitutes by means of objective and subjective scar assessment tools. Methods We retrospectively reviewed the medical records of 78 patients who had undergone autologous split-thickness skin graft with or without concomitant acellular dermal matrix (CGDerm or AlloDerm) graft. We examined graft survival rate and evaluated postoperative functional skin values. Individual comparisons were performed between the area of skin graft and the surrounding normal skin. Nine months after surgery, we compared the skin qualities of CGDerm graft group (n=25), AlloDerm graft group (n=8) with skin graft only group (n=23) each other using the objective and subjective measurements. Results The average of graft survival rate was 93% for CGDerm group, 92% for AlloDerm group and 86% for skin graft only group. Comparing CGDerm grafted skin to the surrounding normal skin, mean elasticity, hydration, and skin barrier values were 87%, 86%, and 82%, respectively. AlloDerm grafted skin values were 84%, 85%, and 84%, respectively. There were no statistical differences between the CGDerm and AlloDerm groups with regard to graft survival rate and skin functional analysis values. However, both groups showed more improvement of skin quality than skin graft only group. Conclusion The new dermal substitute (CGDerm) demonstrated comparable results with regard to elasticity, humidification, and skin barrier effect when compared with conventional dermal substitute (AlloDerm).