Microsurgery, complex reconstruction, and fellowships.
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Fellowships and Scholarships↗
Biomedical subjects
William C Lineaweaver
Publications and source records attributed to William C Lineaweaver.
New microsurgical applications: implications for the infrastructures of plastic surgery.
As a technical innovation, microsurgery has changed concepts and strategies throughout plastic surgery. The infrastructures of plastic surgery currently are evolving in ways that make the identity and future of the specialty uncertain. Microsurgery also may be a basis for fresh thoughts in these areas of infrastructure. This article touched on some areas where microsurgery could be an important element in organizational development, namely patient population identification, economic strategies, academic organization, and medical education. More thorough exploration of these ideas and identification of others may result in a new foundation for plastic surgery with microsurgery as a key element.
Bone Transplantation↗
Assessment of the patency of microvascular venous anastomosis.
There is an absence of data on the timing of occlusion of vessels after anastomosis, and on the possible subsequent reopening (recanalization) of these vessels. This lack of information may be an important factor in the wide discrepancies found among reported patency rates for laboratory microvascular repair. In this study, a total of 300 standard microsurgical anastomoses were performed on rat femoral veins. The patency of each anastomosis was assessed at regular intervals within a 2-week study period. These results showed that the majority of venous occlusions occurred within 1 day after repair. Recanalization of the occluded vein was first seen at day 3 postoperatively. Recanalization was observed over a 2-week postoperative period with increasing frequency. The authors conclude that the optimal time to assess the technical outcome of experimental venous patency is 1 to 2 days after the repair.
Anastomosis, Surgical↗
Autogenous venous graft with one-stage prepared Schwann cells as a conduit for repair of long segmental nerve defects.
The use of autogenous venous graft with intraluminal injection of Schwann cells to enhance nerve regeneration of long segmental nerve defects was evaluated in a rabbit tibial nerve-repair model. Schwann cells were isolated from the excised rabbit tibial nerve by using the polylysine differential adhesion method. The cultured cells were identified by immunocytochemical labeling for S-100 protein. Tibial nerve defects in 4-cm segments were created in 24 animals, which were then divided into three groups. In Group 1, the tibial nerve defect was repaired with interposition vein graft alone; in Group 2, the nerve defect was repaired with a vein graft with intraluminal injection of Schwann-cell suspension; in Group 3, the nerve defect was repaired by autogenous nerve graft alone. At 2 months postoperatively, electrophysiologic evaluation showed that an evoked muscle action potential was recorded for the animals in Group 2, with vein grafting plus Schwann cells, and for those in Group 3, with autogenous nerve grafting, but not for those in Group 1, where vein grafting alone was used. The average motor nerve conduction velocity in the group with vein grafting and Schwann cells was 3.4 +/- 1.5 m/sec, which was slower than the nerve grafting group (7.8 +/- 1.8 m/sec). Histologic analysis confirmed there was formation of new nerve fascicles with myelination in the vein graft filled with Schwann cells. No nerve regrowth was found in the vein grafts without Schwann cells. These results suggested that isolated Schwann cells are able to survive in a vein graft, and that the vein graft with intraluminal seeded Schwann cells could be an alternative for repairing injured nerves with long gaps.
Action Potentials↗
Effect of sequence, timing of vascular anastomosis, and clamp removal on survival of microsurgical flaps.
The effects of the timing and order of clamp removal in microsurgical transplants were studied in rat groin skin flap and rat latissimus dorsi muscle flap models. Forty rats were divided into four groups. In Group 1, the arterial pedicle of the skin flap was anastomosed first, and the clamp was released after the anastomosis was completed. The venous pedicle was then repaired after inflow was restored. In Group 2, the venous pedicle of the skin flap was anastomosed first. The venous clamp was not released until completion of the arterial anastomosis. In Group 3, the arterial pedicle was anastomosed first in the muscle flap. The venous anastomosis was then performed after the arterial clamp was released. In Group 4, the venous pedicle was anastomosed first, and both clamps were released simultaneously. The blood perfusion of the skin flaps was examined after both clamps were released in Groups 1 and 2. The flap survival status was examined 5 days postoperatively for skin flaps and at 3 days for muscle flaps. Skin flaps in an additional six rats were harvested for histology. The results showed that the flap blood flow for Group 1 was statistically significantly higher than for Group 2 flaps in the first 20 min after reperfusion. There was no significant difference of flow between these two groups during the 30 to 90 min after reperfusion. The difference in survival rates for the four groups was not significant. Histology revealed extensive congestion in the flaps from Group 1 after completion anastomoses, but the congestion was significantly decreased at 3 hr following reperfusion. In conclusion, a brief venous stasis during anastomosis, after establishment of arterial inflow, is not detrimental to flap survival. The sequence of anastomosis will not affect outcome for either the cutaneous flap or the muscle flap models. Early flap perfusion was increased when the arterial anastomosis was performed first.
Analysis of Variance↗
Role of free radicals in necrosis of skin graft compromised with hematoma.
It has been observed previously that a hematoma affects skin flap survival adversely through free radical action. The current study was undertaken to determine whether similar mechanisms are operative in skin grafts. The experiment was divided into two parts. During part I, 2 x 2 cm2 split-thickness skin grafts (STSGs) were harvested from 18 Fischer rats and were divided randomly into three groups (each consisted of six grafts), and incubated with plasma, blood, and blood plus 70 mg deferoxamine for 48 hours respectively. Tissue samples were assayed for lipoperoxidation (malondialdehyde [MDA]), superoxide dismutase (SOD), and nitric oxide synthase (NOS). During part II, 36 STSGs were harvested and were divided randomly into three groups. The grafts were incubated as in part I for 48 hours. The STSGs were then affixed to the same dimension recipient beds created on the back of 36 inbred rats. Survival was evaluated 7 days postoperatively. The results showed that there was no significant difference in MDA and NOS levels between each incubated graft group in part I. Only the SOD level in both grafts incubated with plasma and blood plus deferoxamine were significantly higher than the grafts over blood alone (p < 0.05). During part II, there was no significant difference of the average STSG survival percentage between the groups incubated with blood and blood plus deferoxamine (35.8 +/- 6.5% and 52.0 +/- 9.5%). The survival percentage of the group incubated with plasma was 81.8 +/- 7.3%, which was significantly higher than the other two groups (p < 0.01). The authors concluded that unlike a distal flap model, the pathological importance of free radicals in survival of the STSG over a hematoma is insignificant. A more likely hypothesis, as suggested by others, is that a hematoma serves as a barrier preventing angiogenesis.
Animals↗
Effect of cryopreservation on patency and histological changes of arterial isogeneic and allogeneic grafts in the rat model.
Vascular grafting is used frequently in the management of length discrepancies between blood vessels. Cryopreservation permits vascular graft storage and aids availability; however, long-term patency of cryopreserved arterial allografts is not well established. Fifty Fisher and 55 Wistar rats were used in the study. Thirty-eight cryopreserved Fisher femoral arterial grafts were transplanted into the femoral arteries of 15 Fisher (cryoisografts) and 23 Wistar rats (cryoallografts). Thirty-two fresh Fisher arterial grafts were implanted into 32 Wistar femoral arteries (fresh allografts). The animals were killed at 1, 4, and 8 months in each group, and graft patency was assessed. One-month graft patency was 100% in all groups. At 4 months, graft patencies were 86%, 100%, and 75% in the cryoisografts, cryoallografts, and fresh allografts respectively. All cryoisografts and fresh allografts were patent, whereas all the cryoallografts were occluded at 8 months ( < 0.01). Cryopreserved rat arterial allografts offered satisfactory graft patency up to 4 months after implantation and may therefore be applicable clinically in selected cases.
Animals↗
Assessment of facial tissue expansion with three-dimensional digitizer scanning.
This article reports a three-dimensional (3D) digital color scanning system used in the measurement of facial soft tissue expansion. This system consists of digital scanning equipment, software for stereolithographical (STL) forms and nonuniform rational B-spline (NURBS) surfaces, and a computer-aided design program. Accurate data for the area of scar excision and the expanded cervicofacial flap were obtained by using this measuring system in a young patient with scar contracture of the face. This technique can accurately model the reconstruction and make plastic surgery planning a truly interactive procedure.
Adolescent↗
A tribute to Richard F. Edlich, M.D., Ph.D., editor-in-chief. Journal of long-term effects of medical implants.
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General Surgery↗
Gene transfer with DNA strand technique and peripheral nerve injuries.
Although much progress has been made, current treatments of peripheral nerve injury often result in only partial recovery. Many methods have been used to improve the surgical exploration for injured nerve repair. However, much less is known about the involvement of complex neurochemical interactions. Several neurotrophic factors have been shown to play an essential trophic role in the development, maintenance, and regulation of neuronal function. These include nerve growth factor (NGF) and several recently identified members of the NGF family. In this article we give an overview of the process of peripheral nerve injury and regeneration, review the roles of Schwann cells and neurotrophic factors, and summarize perspectives on how gene therapy with viral vectors and cell-mediated DNA strand technology may be used to improve treatment of peripheral nerve injuries.
Gene Transfer Techniques↗
Growth factors and gene transfer with DNA strand technique in tendon healing.
Growth factors are likely to be critically involved in all aspects of tendon healing and many studies, in vitro and in vivo, have tried to define the role of growth factors in this process, and to determine appropriate strategies for their use in tissue engineering to improve the healing of tendons. Gene transfer, with DNA strand technique, may offer the optimal vehicle for growth factor delivery to improve tendon healing. In this article, we will discuss phases of tendon healing, review recent work that has shown the role that growth factors play in this process, describe the potential that experimental gene transfer has in delivering these growth factors to the local wound environment, and outline perspectives for improvement of tendon healing.
Female↗
DNA strand gene transfer and bone healing.
Continued research is still needed to broaden the understanding of the biology of bone formation, bone repair, and bone remodeling. Preliminary data reviewed in this article confirm that it is possible to use ex vivo and in vivo gene-transfer strategies to transfer genes to bone and express them in the repair site. As work progresses, strategies of gene therapy with osteoinductive-growth factors may provide the orthopedic surgeon with more effective and less-costly treatment options for bone-healing problems.
Bone Remodeling↗
Skin wound healing and cell-mediated DNA transport.
Since the discovery of epidermal growth factor (EGF) in 1972, a major emphasis in the study of wound healing has been the role of growth factors and cytokines, and identification and characterization of growth factors and cytokines and their use as therapeutic agents has been a major area of clinical and basic research. This article presents an overview of the process of wound healing of the skin and perspectives on how gene therapy and DNA technology may be used to improve treatment of wounds.
Biological Transport↗