摘要:

Contoured wounds needing closure with skin grafts are often located in complex anatomic regions or are in unusual positions, which make conventional skin graft stabilization techniques cumbersome and ineffective. Often after 72 hours, a skin graft covered with a bolstered dressing has poor take secondary to shear stresses, as well as hematoma formation or serum collection, negating the effectiveness of the stabilizing dressing. The Food and Drug Administration has recently approved vacuumassisted closure (V.A.C.), an innovative technique using negative pressure, for closure of chronic wounds. This reportedly leads to enhanced granulation tissue formation and consequently more rapid reepithelialization of wounds compared with conventional packing with saline-moistened gauze. Experimental studies have demonstrated increased oxygen tension, decreased bacterial counts, and increased granulation formation occurring under negative-pressure systems. Extending the use of this concept, we have coupled skin grafting with negative-pressure dressings for closure of large, complex open wounds. Our results indicate greater than 95% graft take in all patients in this study. This technique is extremely efficacious, with increased graft take due to total immobilization of the graft, thereby limiting shear forces, elimination of fluid collections, bridging of the graft, and decreased bacterial contamination. Moreover we have noted decreased edema in rotated muscle flaps, improved contour conformity, and shortened hospitalizations.

ISSN:0148-7043    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Coverage of midline posterior wounds presents a challenge to the reconstructive surgeon, especially when spinal stabilization hardware has been present and exposed in the wound. Most commonly those wounds that involve the mid to upper thoracic spine have been covered by latissimus dorsi muscle or musculocutaneous flaps. Lower midline wounds, especially in the thoracolumbar region, have needed more complex means of coverage. These have included reversed latissimus dorsi flaps, free flaps, extended intercostal flaps, or fasciocutaneous rotation flaps. We have utilized a far simpler and effective muscle flap: the paraspinous muscle flap. We have raised paraspinous muscle flaps bilaterally and have been able to cover a number of difficult wounds. The wounds were presented by 8 patients with exposed Harrington rods, 3 patients with cerebrospinal fluid leaks, and 1 patient with exposed spinous processes. The wounds in 5 of these 12 patients were in the upper thoracic region, where a latissimus flap was utilized as an additional layer of muscle coverage. The other seven patients had wounds in the lower midline region below the potential reach of the latissimus dorsi. In the latter patients the only flaps employed were paraspinous muscle flaps. We had only one failure in all patients, which involved a recurrent cerebrospinal fluid leak in which there was no decompression of the cerebrospinal fluid pressure utilized in the immediate postoperative period to protect the dural repair. In that instance, a leak recurred. This paper presents the method of flap elevation and the results of our series.

ISSN:0148-7043    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Thrombocytosis in patients undergoing free tissue transfer for coverage of posttraumatic lower extremity defects may be associated with an increased incidence of microvascular thrombosis. Patients with isolated lower extremity trauma have an elevated platelet count that peaks approximately 2 weeks after injury. It is our theory that a humoral component of trauma sera is responsible for the induction of this thrombocytosis. Eight patients with isolated soft-tissue and bony trauma were included in the study. Serum was collected at baseline and throughout the study period. Platelet count, leukocyte count, hemoglobin concentration, and hematocrit were determined. Immunoassay for human interleukin-3 (IL-3), IL-6, and IL-11 as well as granulocyte macrophage colony stimulating factor (GM-CSF) were performed by solidphase enzyme-linked immunosorbent assay. Balb-C mice were then injected intraperitoneally with the human trauma sera from all time points. Blood was collected at baseline and throughout the study period for determination of platelet count, hemoglobin, and hematocrit. Mean initial platelet count in the 8 human subjects was 152,000 per cubic millimeter with an average peak to 642,000 per cubic millimeter. IL-3, IL-11, and GM-CSF were not detectable in the serum of any patient. Elevated levels of IL-6 were detected in all patients in a nonspecific pattern. In the murine model, an early and late thrombocytosis was elicited. The early peak averaged 78.6% over baseline whereas the late peak average 81.0% over baseline. The induction by human trauma sera of an early and late thrombocytosis in this mouse bioassay supports the theory of humoral mediators. The humoral mediators are yet to be determined but may include IL-6.

ISSN:0148-7043    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Keratoacanthoma of the skin and well-differentiated squamous cell carcinoma are two cutaneous neoplasms that most often occur in sun-exposed sites of light-skinned persons. It is often difficult to distinguish these two from each other either clinically or histologically. The view that these two cutaneous neoplasms are part of the same disease entity is not new. We reviewed 150 patients with these two diseases in an effort to see whether any specific criteria for diagnosis and treatment could be achieved. It is our hypothesis that they are not separate diseases but within the spectrum of the same disease. Keratoacanthoma may be some sort of aborted malignancy or hyperplastic premalignant lesion within the squamous cell carcinoma spectrum. The incidence of metastases from squamous cell carcinoma of the skin may be as high as 3%. We do not have the courage to wait 3 months to see if a potentially invasive and metastatic neoplasm is indeed involutional. Incision biopsy may be wrought with significant histopathological inconsistencies. We believe that early, complete excision is the treatment of choice for all skin neoplasms thought to be keratoacanthoma.

ISSN:0148-7043    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Our understanding of muscle, fascia, and skin flap physiology is based largely on data obtained from rodent, rabbit, or canine models. The presence of a well-developed panniculus carnosus confounds the extrapolation of data from these animals to humans. This study attempted to define microsurgically applicable musculocutaneous and fasciocutaneous flaps in the pig that would be comparable to flaps commonly used in humans. Lead oxide was injected into each axillary artery of three standard white domestic swine. Gross dissection and radiographic studies were used to define the specific anatomic fasciocutaneous territory served by the branches of the circumflex scapular artery. Eight musculocutaneous flaps based on the thoracodorsal artery and eight fasciocutaneous flaps based on the circumflex scapular artery were elevated. Although all flaps survived in their entirety, the fasciocutaneous flaps did not, as in man, have an easily dissectable axial blood supply. This finding suggests that the porcine scapular fasciocutaneous flap, although reliable as a pedicled flap, is difficult to employ as a free tissue transfer.

ISSN:0148-7043    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Injury to the facial nerve in the temporal bone presents a challenge to the recovery of nerve function, in that the fallopian canal in which it lies is poorly vascularized. This study was designed to determine if wrapping an intratemporal facial nerve defect repaired with a cable graft with a well-vascularized temporoparietal fascial (TPF) flap would improve facial nerve regeneration. To evaluate this question, a defect was created in the intratemporal left facial nerve of 10 rabbits. All nerves were repaired using cable grafts. In 5 animals, the nerve graft was wrapped with temporoparietal fascia, whereas in the other 5 rabbits it was not. Three additional animals underwent exposure only. The contralateral nerve served as a control in all animals. Quantitative analysis of the nerve graft 12 weeks after repair revealed greater recovery of original fiber diameter and myelin sheath thickness in TPF flap-wrapped repairs. Histological evidence of improved neural regeneration and functional nerve recovery was also seen in the repairs where the TPF flap was utilized. Nerve conduction and electromyographic studies of the cable-grafted nerve at 6 and 12 weeks were equivocal, however.

ISSN:0148-7043    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Segmental loss of a peripheral nerve has been a challenging reconstructive problem. Management of the nerve gap has been accomplished classically with nerve grafting. However, autogenous nerve grafts are not always available for bridging large nerve gaps, and clinical results of large nerve cable grafts have been disappointing. Newer techniques concentrate on nerve lengthening with different methods. Tissue expansion of peripheral nerves has been producing promising results. Since the introduction of the Ilizarov external fixator, much attention has turned to limblengthening techniques and studies investigating the results of nerve and soft tissues lengthened during the course of this procedure. Primary nerve distraction may be an alternative to nerve elongation, by expansion or nerve grafting to repair the peripheral nerve gap. This study describes a device and a model for peripheral nerve distraction in a rat. Primary nerve distraction will need to be subjected to vigorous studies before clinical application.

ISSN:0148-7043    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Keloids occur only in humans and are characterized by fibroblast overproduction of collagen types I and III. Keloid fibroblasts have been shown to make elevated levels of transforming growth factor beta (TGF-β), a growth factor known to promote extracellular matrix production and fibrosis. Thus, the pathophysiology underlying keloid formation may be driven by the biological activity of TGF-β. Tamoxifen, a synthetic, nonsteroidal antiestrogen has been shown to inhibit keloid fibroblast proliferation and decrease collagen production. The purpose of this study was to determine if a mechanism by which tamoxifen decreases keloid collagen production is through a downregulation of TGF-β. Through a luciferase TGF-β bioassay we found that 4 µM of tamoxifen generated a 49% reduction in total TGF-β activity and 8 µM generated an 85% reduction compared with controls. Thus we propose that one of the mechanisms by which tamoxifen decreases keloid fibroblast collagen synthesis is by decreasing TGF-β production.

ISSN:0148-7043    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Growth factors play a crucial role in the regulation of cellular proliferation and matrix degradation in wound healing and cancer. We have shown that thrombospondin 1 (TSP-1) and its cysteineserine-valine-threonine-cysteine-glycine (CSVTCG)-specific receptor play a key role in cell invasion and matrix degradation in different carcinomas. The present study was done to determine whether TSP-1 and its receptor show a similar pattern of expression in wound healing and cancer. Expression and localization of TSP-1 and its receptor were determined in fetal wounds, adult burn wounds, and different human malignancies by immunohistochemical staining and computerized image analysis. In healing wounds, TSP-1 was expressed in the stroma early in the process, followed by a steep decline. The TSP-1 receptor localized to neovessels and highly proliferating cells (i.e., fibroblasts, basal cells), its levels remaining relatively constant. Cancer cells and tumor-associated microvessels expressed the TSP-1 receptor, whereas TSP-1 localized predominantly to the tumor-associated stroma. These data suggest a critical role for TSP-1 and its CSVTCG-specific receptor in wound healing and cancer.

ISSN:0148-7043    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

In response to the recent controversy over silicone gel implants, alternative substances are being sought to offer new options in bioimplantable materials. Polyester is a Food and Drug Administration-approved prosthetic material utilized in vascular grafts for decades without significant problems in body tolerance. Working with textile scientists, polyester (both in its woven and fibrous forms) was engineered to influence differential fibrous ingrowth. Implants of medical-grade polyester were constructed in a 3-cm2diskette configuration. Four combinations of material with varying layers of weave and fiber were created to influence tissue ingrowth differentially. Four implants were placed in separate dorsal pockets beneath the panniculus carnosus of each of 12 adult female New Zealand White rabbits. Care was taken to sort the implant types equally among the four quadrants such that a similar distribution of implants existed between animals. Implants with intact capsules were harvested at 1, 3, and 6 months, and were analyzed for histology, capsular thickness, and tissue ingrowth. A phantom mammogram was taken through the implant material that did not obscure interpretation. The materials were further tested to determine fiber fill-to-wet implant weight ratios to determine postimplantation weight predictably. Tensile strength was also determined.

ISSN:0148-7043    

出版商:OVID    

年代:1998

数据来源: OVID