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Biomedical subjects

J Upton

Publications and source records attributed to J Upton.

At least 55 records · Page 3Linked to original sources
PubMed1995

Fascial flap coverage of Achilles tendon defects.

The exposed, often desiccated Achilles tendon presents a difficult wound that cannot always be solved with the use of regional tissue. A series of 15 consecutive patients with wounds associated with previous failed repairs (n = 5), radiation (n = 1), trauma (n = 4), pressure sores (n = 3), and burn contractures (n = 2) is presented. Patients with osteomyelitis of the calcaneus were not included. All were covered with free fascial flaps from parietotemporal or forearm donor sites and skin grafts. There were two partial flap losses. Complications were minimal, and all patients were mobilized and ambulating within 2 months. Average follow-up was 4 years. Those with peripheral vascular insufficiency were revascularized prior to free tissue transfer. Vascularized fascia covered with skin grafts provides the treatment of choice for the localized Achilles tendon exposure not exceeding 10.0 cm. Advantages include (1) provision of thin, pliable tissue that permits gliding, (2) minimal bulk, (3) simultaneous donor- and recipient-site dissections, (4) transfer of mobile tissue that can be wrapped around tendon, and (5) early wound coverage and mobilization.

Achilles Tendon↗
PubMed1995

Pediatric hand tumors. A review of 349 cases.

Ganglion cysts, foreign bodies and vascular malformations are some of the most common causes of a palpable mass in the pediatric hand. There are other rarer tumors, such as digital fibromas, which are unique to the pediatric population. Malignant tumors are exceedingly rare. An awareness of both the common and unusual tumors seen in the pediatric population is essential for the hand surgeon evaluating these patients.

Adolescent↗
PubMed1995

Vascular tumors in children.

Tumors with a vascular component are the most common masses seen in children. Malformations and hemangiomas predominate. Hemangiomas have a biphasic natural history consisting of initial proliferation followed by spontaneous involution; these tumors rarely require surgical intervention. Malformations present at birth or shortly after birth and have a wide spectrum of clinical presentations depending upon their predominant cell type and rheology. Physical examination and MR imaging will effectively define most of these anomalies. Surgery is reserved for very symptomatic lesions and is effective in all but the fast-flow, Type C group of malformations. Glomus tumors, pyogenic granulomas and both traumatic and iatrogenic aneurysms are also seen in the pediatric age group. All are benign and effectively treated surgically. Malignant vascular tumors are rare in this age group.

Aneurysm↗
PubMed1995

The expanded scapular flap.

The scapular fasciocutaneous flap is a very reliable free tissue transfer, but its size and/or thickness may limit its use in some patients. Scapular fasciocutaneous flaps were expanded for 6 to 12 weeks prior to transfer in 14 patients. The flaps ranged in size from 96 to 1885 cm2 and were used to cover chronic soft-tissue defects. Twelve were transferred as free flaps to distant sites, while two were transferred as pedicled flaps to the ipsilateral extremity. The pedicled flaps were designed across the entire back to incorporate both scapular territories but were rotated on a single vascular pedicle. All flaps survived, but three had marginal distal necrosis not related to the microvascular anastomoses. Two flaps transferred by microsurgical technique developed arterial thromboses requiring revision of the anastomoses. Three patients developed partial donor wound dehiscence after transfer of large flaps that healed by secondary intention in two cases and required a split-thickness skin graft for donor-site closure in the third. Flap expansion produces a delay phenomenon that augments blood supply and increases the area of skin that can survive on a single vascular pedicle. This technique may be useful in selected patients in whom a large, thin fasciocutaneous flap is required and there is sufficient time to allow flap expansion prior to transfer.

Adolescent↗
PubMed1994

Experimental tracheal replacement using tissue-engineered cartilage.

The authors tested the feasibility of using tissue-engineered cartilage, grown in the shape of cylinders, for replacing large circumferential defects of the cervical trachea in rats. Chondrocytes obtained from the shoulder of newborn calves were seeded onto a synthetic nonwoven mesh, 100 microns thick, of polyglycolic acid fibers 15 microns in diameter, cut into pieces of 2.5 x 4 cm. Twenty cell-polymer constructs were wrapped around silastic tubes and implanted into 10 nude mice for 4 weeks. Specimens were then excised and evaluated grossly and histologically for the presence of new cartilage, and biomechanically for their ability to resist collapse upon application of negative pressure. Six cylinders of tissue-engineered cartilage were then sutured into large circumferential defects created in the cervical tracheas of nude rats to replace the excised trachea. Implantation of cell-polymer constructs resulted in the formation of cylinders of hyaline cartilage. When placed within the lumen of a segment of bowel denuded of its mucosal lining, the hollow cylinders resisted collapse in all instances upon administration of negative 200 mm Hg pressure. The cartilage was grossly and histologically identical to that from which the cells had been initially isolated. Four of the six animals receiving these cartilage cylinders as tracheal replacements survived the procedure and were able to breathe in an unassisted fashion. Three of these animals never recovered fully from the anesthetic and the operation, and expired at 24, 48, and 72 hours. The fourth animal fully recovered from the procedure, and breathed spontaneously for 1 week, with no apparent limitations. Increasing respiratory distress then developed, and the animal died.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Design of nasoseptal cartilage replacements synthesized from biodegradable polymers and chondrocytes.

Reconstructive and aesthetic surgery of the nose is a challenging problem in facial plastic surgery. In this study, biodegradable polymers composed of polyglycolic acid (PGA) and poly-L-lactic acid (PLLA) and their co-polymers were used to produce templates to transplant cells and promote regeneration of structural cartilage. A highly porous anatomically shaped three-dimensional non-woven PGA fibre network was sprayed with a coating polymer solution. Reinforcement of the outer circumference of the 12 nasoseptal constructs using high molecular weight PLLA further stabilized the constructs during the process of neomorphogenesis of cartilage, both during in vitro incubation and in vivo implantation. These cell transplantation devices also proved to be adhesive substrates for dissociated bovine chondrocytes. When implanted subcutaneously into nude mice, the polymer templates guided the reorganization after 8 wk of the bovine chondrocytes into neocartilage in the precisely designed size and shape of the original size and shape of the polymer delivery device. All implants loaded with chondrocytes showed evidence of formation of histologically organized hyaline cartilage. The implantation of nasal scaffolds without cells did not show cartilage formation. The technique of tissue engineered growth of cartilage has potential applications in orthopaedic, plastic and reconstructive, and craniomaxillofacial surgery.

Animals↗
PubMed1994

Acquired arteriovenous fistulas in children.

Five boys with acquired arteriovenous fistulas are presented; four had factor VIII deficiencies, and one had a hepatic-induced coagulopathy. The cause of the fistula was the trauma induced by single or repeated venous and/or arterial punctures. All five developed a slowly progressive pulsatile mass of over a period of months. Patients with coagulopathies all developed complications with repeated inadvertent puncture of these masses. Clinical examination and magnetic resonance imaging scans clearly highlight this problem. Surgical ligation is recommended for progressive enlargement.

Arteriovenous Fistula↗
PubMed1994

The use of prefabricated fascial flaps for lining of the oral and nasal cavities.

Twelve temporoparietal fascial flaps were prefabricated to line the oral and/or nasal cavities in 10 patients. Bilateral flaps were used both in a patient suffering from lye ingestion and in a patient undergoing bilateral lip reconstruction. All reconstructions were performed in two stages separated by 3 to 4 weeks. The first stage involved creation of an epithelial lining by placing a non-hair-bearing skin graft over the temporoparietal fascia. The second stage raised the fascial flaps as vascular islands and transferred them as either pedicled or free flaps. All 12 flaps survived and improved function for the patients involved. Although all possible applications for this flap have not been explored fully, there appears to be great potential for the use of this procedure in refined reconstructions of moderately sized intraoral and nasal defects.

Adult↗
PubMed1994

Bone defect repair with tissue-engineered cartilage.

We tested the efficacy of a new approach for the tissue-engineered growth of cartilage developed in our laboratory in repairing surgically created bone defects in the craniums of rats. Large cranial defects were created bilaterally in the frontoparietotemporal bones of athymic nude rats (n = 10). There was gross evidence of new cartilage in 8 of 10 experimental defects that had been filled with a synthetic biocompatible, biodegradable polymer template that had been seeded in vitro with freshly isolated chondrocytes. The control defects, filled with either nothing at all or a polymer template without chondrocytes, showed no evidence of cartilaginous repair (0 of 10). Statistical analysis using McNemar's test with pooled samples showed significant differences between the two groups (p < 0.05). Prior reports concerning the biologic repair of bony defects involved stimulation of adjacent mesenchymal tissue and resulted in ingrowth of new bone. To our knowledge, this is the first report of structural cartilaginous repair of a bony defect with matrix secreted by implanted chondrocytes.

Animals↗
PubMed1994

Tissue-engineered morphogenesis of cartilage and bone by means of cell transplantation using synthetic biodegradable polymer matrices.

This article discusses the development of a technology that allows the tissue-engineered generation of new bone and cartilage. This was accomplished by seeding a high density of functional, dissociated cells onto synthetic biocompatible, biodegradable polymers of different chemical compositions and physical configurations, and then transplanting these polymers into animals. The synthetic scaffolds act as a basement membrane providing for structural cues and enabling nutrition by diffusion until grafting occurs. The development of this field since its inception as well as several potential applications in plastic and reconstructive surgery and in the study of the mechanisms of morphogenesis of bone and cartilage are discussed.

Animals↗
PubMed1994

Cartilage engineered in predetermined shapes employing cell transplantation on synthetic biodegradable polymers.

Cartilage is often used as structural support tissue for cosmetic repair in plastic and reconstructive surgery. We describe the efficacy of a new approach for the generation of cartilage in predetermined shapes using specially configured biodegradable synthetic polymer devices as delivery vehicles for transplanted cells. Synthetic biodegradable polymer scaffolds were configured in one of four specific shapes, i.e., a triangle, a rectangle, a cross, and a cylinder. The polymer matrices were seeded with freshly isolated bovine articular chondrocytes and then implanted subcutaneously into nude mice. Gross examination of excised specimens 12 weeks after implantation revealed the presence of new hyaline cartilage of approximately the same dimensions as the original construct. This cartilage showed no signs of resorption or overgrowth over the 12-week time course of the experiment. Histologic evaluation using hematoxylin and eosin stains confirmed the presence of normal mature hyaline cartilage in 46 of 48 specimens. These results suggest that cartilage can be created in predetermined shapes and dimensions using cell transplantation on appropriate polymer templates. This technology would be useful in cosmetic and reconstructive surgery.

Animals↗
PubMed1993

Pediatric free tissue transfer: an evaluation of 99 cases.

OBJECTIVE: To evaluate the results of free tissue transfers in children who undergo reconstructive surgery. DESIGN: Case series chart review. Mean follow-up longer than 2 years. SETTING: Two tertiary care pediatric hospitals. PATIENTS: Consecutive sample of 99 children. INTERVENTIONS: Free tissue transfers for reconstruction of a variety of defects. MAIN OUTCOME MEASURES: Indications, operations, complications, survival. RESULTS: The most common indications were for restoration of muscle function and for difficulties with soft-tissue coverage. Multiple donor sites were used, with the gracilis muscle, fibula, latissimus dorsi and groin flaps predominating. The overall survival rate was 99.0%. Complications were common, with an overall rate of 59.6%; most were graded as minor or moderate. CONCLUSIONS: Meticulous planning is paramount in achieving a successful outcome. Complications are common but do not include vascular spasm. Free tissue transfers can be successfully completed in small children despite the dimensions of the tissues.

Adolescent↗
PubMed1992

Hand reconstruction with allograft demineralized bone: twenty-six implants in twelve patients.

A long-term study of 26 phalangeal or metacarpal defects that were reconstructed with allogeneic demineralized bone implants demonstrates healing comparable to that which follows autogenous bone grafting. Average follow-up was 54 months. Five patients had multiple enchondromas (Ollier's syndrome), five children had congenital hand deformities, and all of these had previously had bone grafts harvested for associated craniofacial reconstructions. With the use of demineralized bone implants, tourniquet and operative times were significantly reduced and potential donor site morbidity was eliminated. Further, regional anesthesia was used more frequently and hospitalization time was reduced. There were no postoperative complications. Demineralized bone implants have been particularly useful in patients who previously had refused bone grafting.

Adolescent↗
PubMed1992

The use of scapular and parascapular flaps for cheek reconstruction.

This is a retrospective review of our experience with microvascular transfer of scapular and parascapular flaps for the correction of lateral facial contour deficiencies. Twenty-eight patients with congenital (n = 8) and acquired (n = 20) defects were treated with 30 flaps; two patients had bilateral flaps. The etiology of the defects included hemifacial microsomia (n = 2), oblique facial cleft (n = 1), Romberg's hemifacial atrophy (n = 5), neoplasm (n = 4), irradiation (n = 8), trauma (n = 4), tumor excision (n = 4), facial lipodystrophy (n = 2), and silicone granuloma (n = 2). The follow-up evaluation was from 2 to 13 years, with an average of 6 years. Fabrication of a facial moulage was part of the preoperative planning for each patient. These were compound flaps, including skin, deepithelialized skin, fat, fascia, and bone, if necessary. All flaps were constructed with an intact skin paddle for postoperative monitoring. Based on dissections and anatomic findings at operation, several variations in the level of emergence of the circumflex scapular artery from the triangular space and its branching patterns were noted. All flaps survived; changes in the patients' weights were reflected in the flaps. Twelve patients required secondary procedures: excision of skin monitor islands, scar revisions, debulking, or flap resuspension to the malar region. Bone grafts or alloplastic implants were necessary in four patients in whom the malar eminence could not be adequately corrected by transfer of a flap. The deepithelialized scapular/parascapular flap is preferred for correction of large lateral facial defects.

Adipose Tissue↗