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At least 613 records · Page 34Linked to original sources
PubMed1993

Mitotic activity in expanded human skin.

In 20 patients subjected to breast reconstruction by means of tissue expansion, a skin biopsy was obtained at the vertex of the breast before and the day after expansion. Samples were incubated in [3H]thymidine, and the number of labeled cells were counted. A statistically significant rise in the number of labeled basal and suprabasal keratinocytes was seen after expansion. The findings suggest a net gain of tissue not only by stretching but also by formation of new tissue generated by tissue expansion.

Biopsy↗
PubMed1999

[The identification of the criteria of malignancy and the tissue characterization of expansive processes in periskeletal soft tissues. The current role of magnetic resonance].

INTRODUCTION: Expansive masses arising from periskeletal soft tissues are a frequent challenge for the imaging specialist. Lesion diagnosis and characterization, and the assessment of benign/malignant nature are very important factors for treatment planning. We investigated MR capabilities in distinguishing benign from malignant masses and for histopathologic lesion characterization, also in the light of the latest most authoritative literature reports. MATERIAL AND METHODS: February 1995 to November 1997, we examined 237 patients with known space-occupying lesions arising from periskeletal soft tissues. T1- and PD/T2-weighted SE images were acquired on the most suitable planes. The findings were independently evaluated by two groups of radiologists who were asked a benignity/malignancy judgment based on specific morphological criteria and then a presumptive histopathologic characterization. The results were then compared with pathologic findings. RESULTS: We had high agreement rates for benignity/malignancy judgements, with only < or = 3.8% error rates. In contrast, rates were quite variable for histopathologic characterization and differed greatly by lesion type. The lesions, defined as malignant, could not be characterized histologically in approximately 18% of cases by both groups. DISCUSSION AND CONCLUSIONS: Our results, which are in substantial agreement with the recent authoritative literature, confirm MRI as an extremely reliable tool for distinguishing benign from malignant expansive masses arising from periskeletal soft tissues. On the contrary, MRI exhibits good specificity in histopathologic characterization only for the masses with such development as to permit identification of the anatomical compartment of origin, which are usually benign, as well as the masses with typical or pathognomonic tissue signal.

Adolescent↗
PubMed1968

Endotoxin as adjuvator to the transplantation of a mouse mammary tumor.

The mouse mammary tumor MT 296 was used in a further series of experiments on the implantation of tumor, plated out in vivo, from suspensions of individual cells. Lipopolysaccharide from S. typhosa was shown to exert an adjuvator influence. But this adjuvator, an endotoxin, had no direct effect on the suspended tumor cells, unlike the liver preparations previously reported. Lipopolysaccharide from S. typhosa was shown to act on the host. It made the host's connective tissue expanses more susceptible to successful implantation by the tumor cells. It did this only if present at the time these connective tissue expanses were split. The increased susceptibility, caused by splitting the connective tissue expanses in the presence of lipopolysaccharide, declined quickly after 24 hr. The structural changes wrought upon the connective tissues by splitting them in the presence of lipopolysaccharide are described. They show kinship to a Schwartzman reaction of the local type. Their possible role in the adjuvator effect on the plating of single cell suspensions of this tumor is discussed.

Adjuvants, Immunologic↗
PubMed1997

Effect of strain on human keratinocytes in vitro.

Tissue expansion, a technique to enlarge the skin surface area with an expandable balloon, has been widely used in reconstructive surgery. Although the effect of tissue expansion on in vivo skin physiology and histology has been well documented, it remains unclear whether keratinocytes or other cell types are responsible for these changes. Therefore, we investigated the in vitro effect of cyclic (10 cycles/min, 150 mmHg) or constant (continuous, 150 mmHg) strain on human keratinocyte phenotype and relevant mechanosignaling pathways. Our results demonstrate that keratinocytes subjected to cyclic strain exhibit a significant (P < 0.05) increase in cell proliferation (49.2+/-15.8%), DNA synthesis (37.7+/-4.5%), elongation (20.3+/-2.7%), and protein synthesis (17.9+/-6.6% increase) as compared with stationary controls. In contrast, keratinocytes subjected to constant strain were unaffected aside from a modest transitory increase in the proliferative rate. Keratinocytes subjected to cyclic strain aligned perpendicular to the force vector (24.2+/-1.6 degrees) as compared with stationary controls (40.4+/-2.2 degrees; the smaller degree indicates better alignment). We also report strain-induced reduction in the levels of cyclic adenosine mono phosphate (cAMP), protein kinase A (PKA), and prostaglandin E2 (PGE2) as compared with stationary controls (cAMP, 30+/-7.5%; PKA, 45+/-17%; PGE2, 58+/-4.3%; percent decrease vs. that of control). We conclude that direct application of cyclic strain on human keratinocytes modulates cell phenotype and cAMP-mediated signaling pathways in an inverse manner. Moreover, keratinocytes may play an important role in previously observed alterations in skin properties associated with tissue expansion and other strain-induced responses.

Cell Division↗
PubMed1987

Pretransfer expansion of a sensate lateral arm free flap.

Tissue expansion as a reconstructive technique has gained widespread popularity in the field of plastic and reconstructive surgery since Radovan reported his original work in Boston in 1976. Reconstruction by free muscle or composite flaps transferred by microsurgery has preceded the use of tissue expansion. However, a combination of both modalities of reconstruction to fulfill particular reconstructive needs has not yet been reported. This article reports a case of a sensate lateral arm free flap that was expanded prior to its transfer to resurface a 12 X 18 cm defect of the ankle and foot in a child, with primary closure of the donor site. The initial successful resurfacing was followed by recovery of sensation in the entire flap over a period of six months, and the static two-point discrimination measured 9 to 11 mm, which was close to that of the corresponding area of the opposite arm. The child has resumed his sports activities with no problems over a one-year follow-up.

Ankle↗
PubMed2006

Reconstruction of facial burn sequelae utilizing tissue expanders with embodiment injection site: case report.

Although highly specialized burn centers have significantly reduced mortality rates following extensive total body surface area burns, survivors are often left with grotesque facial disfigurement. Hypertrophic scars and tissue defects are the most common cause of functional and aesthetic problems in the head and neck region. Plastic surgeons use full-thickness or split-thickness skin grafts, pedicled flaps, free flaps, transplantation of bone or cartilage and tissue expansion. The authors present a case of a patient who suffered from third-degree flame burns to the face. Prior skin grafting procedures left him with severe scar deformity of the face. The patient was treated utilizing multiple tissue expansion. Facial animation has retained and facial integrity has been aesthetically restored and, with the use of make-up, it is near normal in social settings at conversational distances. The tissue expansion technique is advantageous in facial reconstruction because it makes it possible to resurface even wider defects with neighboring skin, similar in colour and texture, and superior to skin obtained elsewhere.

Adult↗
PubMed1995

Variations in epidermal thickness in expanded human breast skin.

Tissue expansion generates metabolic and morphological changes in the expanded tissues. The alteration of epidermal and dermal thickness has been investigated in many animal studies, but few human studies have been published. We have studied 11 women whose breasts were reconstructed with tissue expansion after mastectomy. The expanded breast skin was biopsied on three occasions: before expansion, at the time of maximal expansion, and six months after the completed reconstruction. Specimens were prepared for light microscopy and epidermal thickness was assessed. There was a significant increase in epidermal thickness (p < 0.05) at the time of maximal expansion. The values before and at six months after reconstruction were not significantly different from each other. We conclude that the epidermis increases in thickness as a result of expansion and returns to normal thickness six months after cessation of expansion.

Biopsy↗
PubMed2004

Reconstruction of difficult wounds with tissue-expanded free flaps.

Tissue expansion of free flaps before transfer have been used to increase the size of the transferred tissue and to allow primary closure of the donor site. This is especially important in burns when there is a lack of healthy tissue, and in children when there is a relative lack of tissue. In this study the authors present their 17-year experience with tissue-expanded free flaps. Between 1985 and 2002, 14 cases of tissue expansion of free flaps before transfer were performed at the authors' institution. The indications for vascularized tissue were 9 facial defects (8 severe burns and 1 neurofibromatosis), 3 large lumbosacral ulcers resulting from spina bifida, 1 large vulvoperineal defect resulting from resection for Chron disease, and 1 large circumferential tissue defect at the lower extremity resulting from tumor extirpation. The flaps were 6 radial forearm, 4 parascapular, and 4 lateral arm free flaps. Tissue expanders were placed under the subcutaneous plane between the deep fascia and the muscle layer, preserving the pedicle architecture and integrity. The size of the tissue expander ranged from 250 to 700 mL and expansions were done either weekly or biweekly for a 10- to 20-week period. The patients were followed for 1 to 17 years. The outcome of the study was based on donor and recipient site morbidity, rate of complications, patient satisfaction, and long-term outcome of the donor and recipient sites. There was no failure in any of the transferred tissue at the recipient site and no tissue loss. Three patients had transient congestion of the free flaps, which resolved without any intervention. In all patients the donor area was closed primarily. One black patient had hypertrophic scar formation at the radial forearm donor site requiring reexpansion and primary closure. In other patients the scar was acceptable. One patient had an infection at the tissue expander site that was treated with removal of the implant and transfer of the free flap to the recipient defect the following day. In 4 patients with facial burns, posttransfer tissue expansion of the free flap at the recipient site was performed for minor revisions at later dates. All patients had good outcomes and were satisfied with the procedure. Preexpansion of free flaps is an effective but underused method. It is safe in terms of complications, results in a better appearing donor site scar, and allows transfer of larger amounts of tissue in patients with tissue deficiency.

Adolescent↗
PubMed1989

Outer table skull erosion causing rupture of scalp expander.

Many various complications have been reported with tissue expansion since it was popularized by Radovan. As expected with any foreign body implantation, the most frequent complication is infection. Rupture of the expander is relatively rare even in the face of overexpansion or blunt external trauma. Complications from tissue expansion of the scalp are similar to those encountered with the placement of expanders elsewhere in the body. We had a case recently involving rupture of an expander placed in the scalp of an 18-month-old child as a result of erosion of the outer table with bone spur formation. This was a local reaction to the pressure exerted by the expander. We present the following case report to document another potential complication with tissue expansion of the scalp.

Bone Diseases↗
PubMed1997

Guided bone regeneration around dental implants in the atrophic alveolar ridge using a bioresorbable barrier. An experimental study in the monkey.

The aim of this study was to evaluate guided bone regeneration (GBR) around dental implants placed in atrophic alveolar ridges using an experimental, nonporous bioresorbable barrier. In 8 Rhesus monkeys, the maxillary canines and lateral incisors were extracted bilaterally and the remaining alveoli were reduced to create atrophic ridges. After a healing period of 3 months, soft tissue expansion was performed using a subperiosteal tissue expander. After 1 month of tissue expansion, and IMZ implant was placed in the atrophic ridge on each side in such a way that its coronal 4 mm to 5 mm remained circumferentially exposed above the bone level. The test implants were covered with a bioresorbable barrier made of poly (D,L-lactid-co-trimethylencarbonate) in a 70/30 ratio, whereas the control implants were covered with a nonresorbable expanded polytetrafluoroethylene (e-PTFE) barrier. The e-PTFE barriers were stabilized with titanium minipins while the bioresorbable barriers were analogously fixed using bioresorbable minipins made of poly (L-lactid-co-D,L-lactid) 70/30. Clinical healing progressed uneventfully in both groups and no soft tissue dehiscences occurred. Histometric and histomorphometric analyses were performed 5 months post surgery. Both test and control implants exhibited direct bone-to-implant contact to variable extents. The mean direct mineralized bone-to-implant contact length fraction was 32% of the total implant length in the test sites and 58% in the control sites. Control sites exhibited significantly greater bone fill compared to the experimental sites (P < 0.001). Histologic observations of test specimens demonstrated a moderate inflammatory reaction related to the degradation and resorption products of the barrier. In conclusion, the nonresorbable e-PTFE GBR barrier was found to be superior to the bioresorbable barriers tested in the present investigation.

Alveolar Bone Loss↗
PubMed1990

[Use of fibrin glue after insertion of an expansion prosthesis].

The concept of tissue expansion is based on the elasticity of the skin which implies its retractability after removal of the prosthesis and insertion of the expanded flap, resulting in tension of the suture margins. Fibrin adhesive applied to the expansion cavity and under the expanded flap has two objectives: to prevent tension of the skin edges/and to prevent sero-haematoma in the expansion cavity. 15 successive cases of expansion prosthesis were successfully treated in this way. The technical protocol and results are presented.

Adolescent↗
PubMed1989

[Tissue expanders in plastic surgery of the head and neck. Indications and use].

Tissue expansion allows a functional as well as an aesthetic reconstruction of local defects and thus corresponds to the actual state of the art in plastic surgery.-Tissue expansion provides tissue of the same quality for the repair of defects without leaving deformities on the donor site. It creates local flaps with skin of the same texture, colour and preserved sensitivity.-The use of tissue expanders has grown enormously during the last few years.-A higher rate of complications on the cheek and on the neck must be taken into account.

Head and Neck Neoplasms↗
PubMed1992

Skin expansion in head and neck reconstructive surgery.

We used a tissue-expansion technique to achieve soft-tissue reconstruction in congenital and acquired defects of head and neck. One hundred and fifty-five head and neck reconstructions have been performed, with a 6 percent rate of major complications. We present our planning and surgical approach for single areas. From a technical point of view, the only major difference from the rest of literature is the approach to the problem of periprosthetic capsule. In fact, we believe that complete removal of the capsule, which can be achieved without vascular risk thanks to a special technique, is necessary to obtain the best results.

Adult↗
PubMed2003

Ureteral tissue balloon expansion for laparoscopic bladder augmentation: survival study.

BACKGROUND AND PURPOSE: The search for the perfect urinary bladder substitute continues. Despite their inherent limitations, intestinal segments remain the commonest material for bladder reconstruction. The ureter, with its transitional epithelium, may be the ideal tissue to augment the bladder. Ikeguchi et al reported the feasibility of chronic ureteral balloon expansion by open surgery (J Urol 1998;159:1665). Herein, we propose a completely minimally invasive approach to balloon overdilate a segment of juxtavesical ureter incrementally and to use this in-line tissue-expanded ureteral patch to augment the bladder laparoscopically. MATERIALS AND METHODS: In five female pigs, a novel ureteral expansion balloon device (Microvasive, MA) was inserted percutaneously and advanced antegrade into the juxtavesical ureter. The device has two channels: one for balloon inflation and the other for draining the kidney. After progressive ureteral expansion over a 3- to 4-week period, laparoscopic augmentation ureterocystoplasty was performed. Animals were euthanized at 15 days (N = 1), 1 month (N = 1), 2 months (N = 1), and 3 months (N = 2). RESULTS: Percutaneous balloon device placement was technically successful in all five cases (mean operating room time 52 minutes). The mean volume of the tissue-expanded ureter at 1, 2, and 3 weeks was 12.9 cc, 60.3 cc, and 171.8 cc, respectively. Laparoscopic augmentation ureterocystoplasty with (N = 3) or without (N = 2) concomitant subtotal cystectomy was technically successful in all five cases without any open conversion. The mean operative time was 126.5 minutes, and the mean blood loss was 29 mL. Postoperative complications consisted of one case each of pyelonephritis and ureteral stricture. At autopsy, the mean capacity of the bladder was 574 mL, and the P(ves) at maximum capacity was 14 cm H(2)O. Histologic examination of the tissue-expanded ureter revealed regenerated transitional epithelium and muscle hypertrophy. CONCLUSIONS: Chronic ureteral tissue expansion can be carried out safely and efficaciously. The expanded tissue is thick, healthy, and vascular, with histologic features of normal transitional epithelium and muscle hypertrophy and hyperplasia. This expanded ureteral tissue can be used to augment the bladder with laparoscopic techniques. Such augmented bladders do not show significant shrinkage and possess urodynamic characteristic of normal capacity and normal compliance over a follow-up of 3 months.

Anastomosis, Surgical↗
PubMed2004

Pregnancy as a tissue expander in the correction of a scar deformity.

Tissue expansion is an established method for the correction of scars and tissue defects. During pregnancy the abdominal skin becomes gradually stretched over the growing uterus, providing a "natural" tissue expander. We present a case of a woman with posttraumatic scarring of the lower abdomen and thigh where tissue expansion during pregnancy was successfully used for scar correction.

Abdominal Injuries↗