Sanghoon Park

Selective recruitment of endothelial progenitor cells to ischemic tissues with increased neovascularization.

Tissue ischemia remains a common problem in plastic surgery and one for which proangiogenic approaches have been investigated. Given the recent discovery of circulating endothelial stem or progenitor cells that are able to form new blood vessels, the authors sought to determine whether these cells might selectively traffic to regions of tissue ischemia and induce neovascularization. Endothelial progenitor cells were isolated from the peripheral blood of healthy human volunteers and expanded ex vivo for 7 days. Elevation of a cranially based random-pattern skin flap was performed in nude mice, after which they were injected with fluorescent-labeled endothelial progenitor cells (5 × 105; n = 15), fluorescent-labeled human microvascular endothelial cells (5 × 105; n = 15), or media alone (n = 15). Histologic examination demonstrated that endothelial progenitor cells were recruited to ischemic tissue and first appeared by postoperative day 3. Subsequently, endothelial progenitor cell numbers increased exponentially over time for the remainder of the study [0 cells/mm2 at day 0 (n = 3), 9.6 ± 0.9 cells/mm2 at day 3 (n = 3), 24.6 ± 1.5 cells/mm2 at day 7 (n = 3), and 196.3 ± 9.6 cells/mm2 at day 14 (n = 9)]. At all time points, endothelial progenitor cells localized preferentially to ischemic tissue and healing wound edges, and were not observed in normal, uninjured tissues. Endothelial progenitor cell transplantation led to a statistically significant increase in vascular density in ischemic tissues by postoperative day 14 [28.7 ± 1.2 in the endothelial progenitor cell group (n = 9) versus 18 ± 1.1 in the control media group (n = 9) and 17.7 ± 1.0 in the human microvascular endothelial cell group (n = 9; p < 0.01)]. Endothelial progenitor cell transplantation also showed trends toward increased flap survival [171.2 ± 18 mm2 in the endothelial progenitor cell group (n = 12) versus 134.2 ± 10 mm2 in the media group (n = 12) and 145.0 ± 13 mm2 in the human microvascular endothelial cell group (n = 12)], but this did not reach statistical significance. These findings indicate that local tissue is- chemia is a potent stimulus for the recruitment of circulating endothelial progenitor cells. Systemic delivery of endothelial progenitor cells increased neovascularization and suggests that autologous endothelial progenitor cell transplantation may have a role in the salvage of ischemic tissue.

Importance of the Chin in Lower Facial Contour : Narrowing Genioplasty to Achieve a Feminine and Slim Lower Face

Background: A prominent mandible and squared contour are typical facial features considered unattractive in Korea and in other Asian countries; thus, mandible reduction is widely practiced. While reviewing the unsatisfactory surgical cases of mandible reduction, the authors discovered that failure was largely because the patients’ chins were left intact. The authors have reached the conclusion that paying attention to the shape of the chin is crucial and therefore correction in the procedure of lower facial contouring surgery is required. Methods: From March of 2003 to April of 2005, 254 women underwent mandible reduction. Of these patients, 39 required correction of chin shape in addition to mandible reduction. Results: Narrowing the chin and modification of chin shape can be accomplished by narrowing genioplasty with central strip resection. This mid-symphyseal sectioning procedure produces safe and very satisfactory results. This procedure not only augments the narrowing effect by leaving soft tissues attached but also enables modification of chin shape by altering the shape of resection. By applying this procedure, additional modifications of the chin to correct asymmetry or microgenia are possible. Conclusion: Narrowing genioplasty, either as a single procedure or in combination with mandible reduction, makes the lower face appear slender and produces a more feminine contour.

Superior gluteal vessel as recipient for free flap reconstruction of lumbosacral defect

&NA; When the lumbosacral soft‐tissue defect cannot be closed with a local flap, the option of a free flap should be considered. However, very few cases of free flaps have been reported, the reason being mainly difficulties in finding a suitable recipient vessel. Several vessels, such as inferior gluteal vessel, extension of thoracodorsal vessel with vein graft were reported as recipient vessels, but each one had its own drawbacks. The superior gluteal vessel has been used as a donor vessel in breast reconstruction after mastectomy but is thought to be undesirable as a recipient for microvascular anastomosis, mainly because of technical difficulty. From May of 1993 to March of 1997, five patients (one man and four women) received microvascular transfer of latissimus dorsi myocutaneous flaps using the superior gluteal vessel as a recipient. Their ages ranged from 11 to 64 years (mean 44 years of age). The causes of lumbosacral defects were tumor (1), trauma (1), radiation (2), and pressure sore (1). Before free flap transfer, the patients received an average of 2.8 operations for sacral lesions. Mean follow‐up period was 12.4 months (2 to 40 months). A lateral approach was used to the superior gluteal vessel after elevation and retraction of gluteus maximus muscle. A thoracodorsal artery and vein were anastomosed to superior gluteal artery and vein in three cases, whereas in two cases, one artery and two veins could be anastomosed. All the flaps survived with complete recovery from sacral lesions. During the follow‐up period, one case of partial skin graft necrosis and one case of a small superficial pressure sore developed, but there was neither dehiscence nor recurrence. The superior gluteal vessel is large in caliber, constant, with numerous branches, lying in proximity to the lesion, and relatively unaffected despite previous radiation. The technical difficulties with the deep location and short pedicle length can be overcome with some modifications in approach to the vascular pedicle. The superior gluteal artery and vein can be used as a recipient for the free tissue transfer when the lumbosacral defects cannot be covered with a conventional method. (Plast. Reconstr. Surg. 101: 1842, 1998.)

Algorithm for recipient vessel selection in free tissue transfer to the lower extremity.

The proper selection of a recipient vessel is essential for the success of free tissue transfer, especially when the transfer is to the lower extremity. However, a general agreement on which vessel to use has not been reached yet. Conflicting data have been reported on the survival and outcome of the transferred flaps, depending on the vessel used or the location of anastomosis. The aim of this study was to identify the patterns and problems in the selection of recipient vessels for free tissue transfer to the lower extremity and to establish a general guideline for proper selection. From September of 1990 to December of 1997, 50 consecutive, microvascular, free tissue transfers were performed on the lower extremity. The causes requiring soft-tissue coverage included trauma (25), unstable scar (11), chronic osteomyelitis (7), and tumors (7). The mean follow-up period was 22.4 months (range, 2 to 41 months). In 25 cases, the posterior tibial vessel was used as the recipient vessel. The microvascular anastomosis was done proximal to the zone of injury in 45 cases. The two most important factors in the selection of a recipient vessel are the site of injury and the vascular status of the lower extremity. Less important factors include the flap to be used, method, and site of microvascular anastomosis. All the currently feasible options for recipient vessels are included, and the opinions of other surgeons are reviewed. A general guideline is established, and an algorithm for the proper selection of a recipient vessel is proposed. This algorithm is a fast and convenient guide for evaluating the wound and planning the free flap to the lower extremity.

Selection of the recipient vessel in the free flap around the knee: the superior medial genicular vessels and the descending genicular vessels.

In reconstructions around the knee, the use of a free flap is indicated in a limited number of cases, but it plays a critical role in cases of extensive defects or unavailability of local flaps. The selection of the recipient vessel is an essential and challenging step for a successful free tissue transfer. Popliteal vessels and other small vessels around the knee have been reported to be used as recipient vessels, but the choice of recipient vessels around the knee has not been established. In this study, after a thorough investigation of the vascular anatomy at the knee region, the superior medial genicular vessels and the descending genicular vessels were considered to be the proper recipient vessels, and a clinical application was tried. From July of 1997 to July of 1999, a total of seven cases of soft‐tissue defects around the knee—four cases in the posterior region and three cases in the anterior region—were reconstructed with free flaps, using the superior medial genicular vessels and the descending genicular vessels, respectively. All flaps survived completely, with no flap loss. The advantages of these vessels are their proximity to the knee and their reliability, versatility, simplicity, and size match. The outstanding characteristic of this combination of vessels is their versatility, because the combination can cover all defects around the knee. The clinical application and the versatility of the combination of the superior medial genicular vessels and the descending genicular vessels as the recipient vessels was confirmed for the reconstruction of posterior and anterior knee defects. (Plast. Reconstr. Surg. 107: 1177, 2001.)

Muscle-splitting approach to superior and inferior gluteal vessels: versatile source of recipient vessels for free-tissue transfer to sacral, gluteal, and ischial regions.

&NA; The superior gluteal vessel has been reported as a recipient in free‐tissue transfer for the coverage of complex soft‐tissue defects in the lumbosacral region, where a suitable recipient vessel is difficult to find. The characteristics of proximity, vessel caliber, and constancy make the superior gluteal vessel preferable to previously reported recipient vessels. However, there are technical difficulties in microsurgery (e.g., short pedicle length and deep location) and muscle injury (transection of the muscle) associated with use of the superior gluteal vessel. The purpose of this article is to present a modification of an approach to the gluteal vessel to alleviate technical difficulties and minimize muscle injury. From August of 1997 to January of 1999, six patients received microvascular transfer of the latissimus dorsi muscle or myocutaneous flap to the sacral (4) and ischial (2) regions. The causes of defects were tumor (1), trauma (1), and pressure sores (4). A musclesplitting approach was used on the superior gluteal vessel and was later applied to the inferior gluteal vessel. The gluteus maximus muscle was split as needed in the direction of its fibers, and the perforators were dissected down to the superior or inferior gluteal artery and vein deep into the muscle. The follow‐up period ranged from 6 to 22 months, and all of the flaps survived with complete recovery of the lesion. The major drawbacks of using the superior and inferior gluteal vessels can be overcome with the muscle‐splitting approach, which provides increased accessibility and additional length to the vascular pedicle while causing minimal injury to the muscle itself. It also proves to be an easy, safe, and reliable method of dissection. When free‐tissue transfer to sacral, gluteal, and ischial regions is indicated, the muscle‐splitting approach to the superior and inferior gluteal vessels is a recommended option in the selection of a recipient vessel. (Plast. Reconstr. Surg. 106: 81, 2000.)

Contouring of the lower face by a novel method of narrowing and lengthening genioplasty.

Background: Lower face contouring surgery has become a popular aesthetic operation in most East Asian countries. Various surgical methods are used to improve lower face aesthetics. However, when a patient has both a short and a wide lower face, a chin-lengthening procedure should be performed simultaneously with narrowing genioplasty. Autogenous bone grafts or alloplastic materials are commonly used to correct this problem, but these surgical methods have several inherent disadvantages. To avoid these complications, the authors devised a novel, simple, and reliable method that can correct a short and wide lower face. Methods: From January of 2010 to December of 2012, a consecutive series of 58 patients underwent chin-narrowing and chin-lengthening surgery. First, the newly designed narrowing and lengthening genioplasty was performed. Then, the mandible lower borders were further contoured to diminish the bony steps at the chin-mandible junction and achieve a smooth and slender jaw line. Results: All patients showed sufficient improvement of their facial contours, and most of the patients were satisfied with their surgical outcomes. No severe complications were noted during the follow-up period. The results were confirmed with postoperative radiographs and medical photographs. Conclusions: As the lower face plays an important role in the aesthetics and balance of the entire face, the authors’ novel surgical tool to narrow and lengthen the chin can provide aesthetically gratifying results when correcting a short and wide lower face. Complications seen with previous chin-lengthening methods were avoided, and the new surgical tool showed reliable and predictable surgical outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Strategic considerations on the configuration of free flaps and their vascular pedicles combined with Ilizarov distraction in the lower extremity.

&NA; For the injury of the lower leg associated with both bone and soft‐tissue defect, the combined free flap and the Ilizarov distraction method were described as a useful treatment modality. During the procedure of distraction, however, revisions were frequently needed to change the pin position or to change the flap configuration. In case of flap ischemia, distraction should be delayed or abandoned. Then, a vascularized bone transfer might be necessary. To avoid these complications and achieve safe distraction, the configuration of the flap with its vascular pedicle should be carefully planned in terms of the future bony lengthening procedures and the concomitant softtissue changes of the lower leg. According to the response of local tissue to the distraction process, the lower limb can be divided into four compartments (active mobile, passive mobile, receptive, and restrictive). The configuration of the transferred free flap with its vascular pedicle can be classified into five types. To minimize the undue forces to the vascular pedicle and reduce the possibility of vascular compromise, the transferred free flap should have the configuration that its vascular pedicle lies in the territory of the mobile compartment. In performing free‐tissue transfer combined with the Ilizarov method in the lower extremity, the configuration of the flap with its vascular pedicle should be carefully planned, and the characteristics of lower leg tissue should be kept in mind during the distraction. (Plast. Reconstr. Surg. 105: 1680, 2000.)

A new classification of palatal fracture and an algorithm to establish a treatment plan.

Palatal fractures have previously been classified according to the anatomic location of the fracture line, which is helpful for understanding the types of palatal fracture, but which is insufficient for helping the surgeon to decide which fracture to open and how to do so. The purpose of this study was to aid in the establishment of a precise treatment plan by determining the surgical approach and the types of stabilization that should be used for different types of palatal fracture. In a retrospective review of 136 consecutive Le Fort maxillary fractures over 6 years, 18 patients (13.2 percent) with palatal fractures were analyzed. The principle of open reduction and internal fixation was applied to all the patients. In six patients (33 percent), exploration and fixation was done in the palatal surface. Eight patients (44 percent) needed an extended period of immobilization (4 to 6 weeks). No major complications were observed during the follow‐up period. An algorithm was devised to help establish a proper treatment plan, and palatal fractures were classified into four types: closed reduction, anterior treatment, anterior and palatal treatment, and combined. The key elements considered in deciding the treatment principle and the classification of a palatal fracture were the possibility of closed reduction, surgical exposure, site of rigid fixation, and stability of fractured segments after rigid fixation. The outcome of reconstruction and the postoperative course differed depending on the type of palatal fracture. This classification scheme provided an easy and simple way to establish a treatment plan and was helpful in learning the treatment principles of palatal fracture. (Plast. Reconstr. Surg. 107: 1669, 2001.)