Contribution of prosthetic therapy in the management of nasopharyngeal stenosis following uvulopalatopharyngoplasty.
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Biomedical subjects
Publications and source records attributed to D Serafin.
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Over a 3-year period, 136 patients were monitored following free autologous tissue transplantation using a laser Doppler flowmeter linked to a computerized data-acquisition system. This monitoring system has indicated perfusion compromise in free flaps more rapidly than clinical observation alone. Most important, this has resulted in an increase in salvage rate from 50.0 to 82.4 percent. In addition, our overall success rate has increased from 92.6 to 97.8 percent since introducing this monitor clinically. Computerization also has facilitated the collection of data, which has enabled us to establish expected values for postoperative blood flow in several types of donor tissues used for microvascular reconstruction. Finally, this computerized monitoring system has relieved personnel from basing decisions on subjective data.
Synthetic conduits have not been suitable for microvascular reconstruction owing primarily to their high thrombogenicity. Vein replacements are the most vulnerable to thrombosis because of their low shear rates and low pressure. Experimental replacement of microvenous segments with prosthetic segments has shown little success. Recent technological advances in biomaterials and control of thrombogenesis provide the potential for success in the development of venous prostheses. The purpose of this study was to assess the use of nonbiodegradable composite polyurethane microvascular prostheses for reconstruction of rat femoral veins. Rat femoral venous defects of 10 mm were reconstructed with autogenous vein (n = 12), unprocessed plain polyurethane (n = 5), and nonbiodegradable composite polyurethane (n = 31). Patency was evaluated by direct observation and proximal venous milking tests. The patency rate of composite grafts was not significantly different from that of isotopic vein (p = 0.5, Fisher's exact test), and both had higher patency than unprocessed polyurethane (p less than 0.01). Composite grafts were examined sequentially using light and scanning electron microscopy. Grafts were fully endothelialized between the first and third months. The neointimal, neomedial, and neoadventitial layers could be seen more distinctly over time. New opportunities in reconstructive microsurgery may be opened by microvascular prostheses that are complaint and thromboresistant.
Ischemia-reperfusion is encountered in a wide variety of surgical situations. The damage resulting from ischemia-reperfusion may be due, in part, to the infiltration and activation of neutrophils into the reperfused tissue. The purpose of the study was to examine ischemia-reperfusion induced neutrophil activation in skeletal muscle. In control muscles, ischemia in the hamster right cremaster muscle was produced for 5 min after an initial 2 hr 55 min perfusion period. In ischemic muscles, ischemia was produced for 3 hr prior to reperfusion. After the clamps were removed, a video recording of the cremaster microvasculature was made using intravital fluorescence microscopy. Acridine orange was infused intravenously 10 min prior to video recording in order to selectively label and enhance the contrast of neutrophils. The number of neutrophils rolling along the endothelium of 40 to 60 microns-diameter venules in a 1-min period increased from 9.0 in control animal cremaster venules to 24.1 following ischemia-reperfusion (p less than .05; n = 11). The ischemia-reperfusion model developed in this study allows for the direct quantification of neutrophil adhesion in skeletal muscle and can be further used to assess pharmacologic minimization of neutrophil-mediated damage in skeletal muscle.
Difluoromethylornithine (DFMO) pretreatment for 7 days improved survival of rat abdominal skin flaps in previous studies. The purpose of this study was to determine if acute administration of DFMO enhances survival. Each rat had a 7 x 7-cm abdominal skin flap raised on a single epigastric neurovascular pedicle. Within 1 minute of pedicle ligation, the rats were given 0, 1, or 4 gm/kg of body weight of DFMO intraperitoneally. Putrescine was administered to additional rats alone or with DFMO. After 48 hours, the percentage of flap survival was estimated using fluorescein injection and planimetry to quantify the perfused and unperfused areas. Flap survival increased from 71 +/- 3% in controls to 83 +/- 2% and 92 +/- 3% in rats treated with 1 and 4 gm/kg of DFMO, respectively (p less than 0.005). Putrescine reversed the protective effect of DFMO, suggesting a specific polyamine-related mechanism. This study indicates that there may be both short- and long-term polyamine pools through which DFMO acts. In summary, DFMO may prove to be important in preventing cell death following acute ischemia.
The purpose of this study was to examine the effects of catecholamines on skin necrosis independent of their vasoactive effects. Rat abdominal or human breast skin was excised, pinned flat, and incubated at 37 degrees C for 6 hours in a buffered salt solution containing catecholamine. At 0.1 and 6 hours the lactate dehydrogenase (LDH) released from the skin and appearing in the buffer was determined spectrophotometrically. All groups showed similar LDH levels at 0.1 hour. Rat skin treated with greater than or equal to 10(-7) M epinephrine (33 times less than the 1:200,000 used clinically) or greater than or equal to 10(-5) M norepinephrine showed a significant increase in the LDH released at 6 hours versus controls (18.75 +/- 1.25 versus 13.75 +/- 1.25 and 29.25 +/- 2.96 versus 22.00 +/- 1.96 IV, respectively). Total tissue LDH levels were not significantly different at 0.1 or 6 hours. The toxic effect of epinephrine was eliminated by the addition of propranolol or selective beta 2 blockade, but not by alpha or beta 1 blockade. Therefore, this effect appears to be mediated largely by beta 2 receptors. Similar toxic effects were seen in human breast skin treated with 1:200,000 epinephrine and were blocked with propranolol. Phenylephrine at 1:20,000 demonstrated toxicity, but angiotensin II and vasopressin did not. These studies indicate that addition of catecholamine to ischemic rat or human skin accelerates skin death within 6 hours, but that the toxicity can be reversed with beta blockade.
The purpose of this study was to determine whether the rate of DNA synthesis in human skin could be increased by UVB radiation and to determine the potential for reversing the stimulatory effects of UVB radiation by alpha-difluoromethylornithine (DFMO). Split-thickness facial skin was grafted onto athymic CD-1 Nu/Nu mice on the anterolateral dorsal surface. Following graft healing for 6 weeks, grafts were treated with 0%, 2%, or 5% DFMO (a potent inhibitor of polyamine biosynthesis) and subsequently irradiated with 0.15 J/cm2 of UVB light. Two days after UVB exposure, [3H]thymidine was injected and the grafts were dissected and counted. Ultraviolet radiation significantly increased thymidine incorporation, indicating increased DNA synthesis. The stimulatory effects of UV radiation were significantly reduced by topical application of 5% DFMO. Thus administration of DFMO most likely decreased the polyamine level and decreased the rate of DNA synthesis, which may have caused a decreased rate of epidermal proliferation. Thus the topical application of DFMO may prove beneficial for UVB exposure and other hyperproliferative states where a decrease in the rate of cell turnover might be desirable.
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A technique utilizing the inferiorly based dermal pedicle nipple-areolar flap is described. The advantages of this technique are:(1) predictable breast shape based on preoperative markings; (2) direct visibility of all areas for ease of resection and hemostasis; (3) retention of normal nipple duct connections; (4) no impairment of subjective sensation; and (5) adequate blood supply. This technique has particular application in younger women, in whom nipple sensation is quite important. The interruption of the intercostal nerve branches is usually limited because of the thickness and width of the inferior pedicles. Utilizing our modifications of the technique originally described, this versatile flap can now be used routinely in reduction mammaplasties requiring the removal of either small amounts (200 gm) or quite large amounts (2,500 gm) of tissue with consistently satisfactory aesthetic results and excellent patient satisfaction.
No technique will serve the needs of all patients requiring a reduction mammaplasty and mastopexy. However, the modified, inferiorly-based dermal flap technique appears to us to offer the most advantages and the greatest latitude for a predictable breast reduction in most of these patients.
We present a patient who bled into the pocket around a breast implant 2 1/2 years after an augmentation mammaplasty. She had received inflatible silicone prostheses, each containing 40 mg of triamcinolone acetonide. Our belief is that this large dosage of corticosteroid was responsible for the late erosion of the medium-sized artery, which caused the hemorrhage. Exploration and evacuation of the hematoma was followed by an uneventful postoperative course.
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Since 1974, 69 patients with extensive defects have undergone reconstruction by microsurgical composite tissue transplantation. Using this method, donor composite tissue is isolated on its blood supply, removed to a distant recipient site, and the continuity of blood flow re-established by microvascular anastomoses. In this series, 56 patients (81%) were completely successful. There have been eight (12%) failures, primarily in the extremities. There have been five (7%) partial successes, (i.e., a microvascular flap in which a portion was lost requiring a secondary procedure such as a split thickness graft). In those patients with a severely injured lower extremity, the failure rate was the greatest. Most of these were arterial (six of seven). These failures occurred early in the series and were thought to be related to a severely damaged recipient vasculature. This problem has been circumvented by an autogenous interpositional vein graft, permitting more mobility of flap placement. In the upper extremity, all but one case were successful. Early motion was permitted, preventing joint capsular contractures and loss of function. Twenty-three cases in the head and neck region were successful (one partial success). This included two composite rib grafts to the mandible. Prolonged delays in reconstruction following extirpation of a malignancy were avoided. A rapid return to society following complete reconstruction was ensured. Nine patients presented for reconstruction of the breast and thorax following radical mastectomy. All were successfully reconstructed with this new technique except one patient. Its many advantages include immediate reconstruction without delayed procedures and no secondary deformity of the donor site. Healthy, well vascularized tissue can now be transferred to a previously irradiated area with no tissue loss. This new method offers many advantages to older methods of reconstruction. Length of hospital stay and immobilization are reduced. The total number of operative procedures required in achieving the desired result is also less, thus decreasing the cost of hospital care.
The use of a free flap to bring in well-vascularized cover for a breast reconstruction (following radical mastectomy) is presented. Eleven of 12 such transfers were successful. (One free groin glap failed, and that reconstruction was abandoned.) Patients for breast reconstruction who have a marked deficiency of healthy, well-vascularized skin and subcutaneous tissue in the area are suitable candidates for this operative procedure. When a free groin flap is transferred, the donor defect is minimal.
Of thirty-five cases of microsurgical composite tissue transplantation, twenty-five (71 per cent) were completely successful, four (11 per cent), were partially successful, and six (17 per cent) failed. If a microvascular flap should fail, older but more lengthy methods of reconstruction may be employed with a reasonable chance for success. The advantages of the donor groin flap are discussed. Operative technic and management are outlined.
A composite free flap based on intercostal vessels may be used to reconstruct in one stage defects around the mandible in which skin, soft tissue and bone are missing. A delay procedure is recommended one week prior to transfer.
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