Survival of free tissue transfer following internal jugular venous thrombosis.
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Aged↗
Biomedical subjects
W C Lineaweaver
Publications and source records attributed to W C Lineaweaver.
Serratus anterior-rib composite flap: anatomic studies and clinical application to hand reconstruction.
Because of its relative ease of dissection, increased length of the vascular pedicle, and excellent diameter for anastomosis, the serratus anterior-rib composite flap has been used to reconstruct bony and soft-tissue defects in the face and lower extremities. However, no data are available on optimal rib level or harvest location. The authors report the results of the vascular anatomy of this flap in 6 fresh cadavers and 2 clinical patients using this flap to reconstruct a defect in the hand. Arteriograms were performed through the thoracodorsal artery, and microscopic dissections were done at the rib periosteum. The sixth through the ninth ribs showed consistent filling of their respective intercostal vessels. The rib segments near the anterior axillary line had the most abundant communicating vessels between the serratus and the periosteum. In two patients, the serratus-rib composite free flap provided excellent bone and muscle length for reconstructing the first metacarpal defect.
Adult↗
Patterns of flap loss related to arterial and venous insufficiency in the rat pedicled TRAM flap.
Vascular supply to the contralateral portion of the conventional transverse rectus abdominis musculocutaneous (TRAM) flap (zone IV) may become compromised, resulting in partial flap loss and requiring segmental excision. The etiology of this necrosis is not clear. This study determines skin necrosis patterns on a superiorly pedicled caudal TRAM flap during conditions of venous and arterial insufficiency, and determines whether cutaneous venous outflow can sustain a flap with venous insufficiency. Twenty-eight adult male Sprague-Dawley rats underwent superior pedicled TRAM flap elevation, and the zones were marked on the skin paddle. The animals were divided into four groups: control (group A, N = 6), arterial ligation (group B, N = 6), venous ligation (group C, N = 8), and venous ligation with cutaneous venous outflow (group D, N = 8). After 10 days, the skin paddle was photographed and the areas of necrotic skin were measured. Results showed that group B (selective arterial ligation) had 51.7 +/- 2.8% and 40.0 +/- 2.0% skin necrosis in zones I and II respectively. Zone I necrosis was significantly greater in group B compared with the control (p < 0.05). Group C (selective venous ligation) resulted in 73.8 +/- 16.4% and 93.8 +/- 33.4% skin necrosis in zones III and IV respectively. This necrosis was significantly greater compared with the control (p < 0.001). Group D rats' lateral skin necrosis compared significantly less with group C (p < 0.001). These results demonstrate that the patterns of flap necrosis in rat TRAM flaps with poor arterial inflow differ from those with venous stasis. Necrosis of the contralateral portion (zone IV) of human TRAM flaps may be related to problems with venous stasis; thus, a cutaneous venous outflow may prevent this problem.
Animals↗
Effects of VEGF administration following ischemia on survival of the gracilis muscle flap in the rat.
The incidence of free flap transplantation failure is only 3% to 5%, yet still occurs in cases in which the flap suffers prolonged ischemia. The purpose of the current study was to determine the effects of vascular endothelial growth factor (VEGF)--a potent angiogenic agent with a suspected role in the protection of endothelium--on flap survival in a model of ischemia-reperfusion injury. The model chosen was the rat gracilis muscle flap. A total of 36 adult male Sprague-Dawley rats were divided into three groups (N = 12). One experimental group received VEGF treatment and the other received heparin. A third group was treated with saline and served as the control. The gracilis muscle flap was dissected and isolated based on a vascular pedicle originating at the femoral vessels. Following 3.75 hours of ischemia, induced by clamping the femoral vessels, either VEGF, heparin, or saline was infused directly into the pedicle of the flap via a cannula. The flaps were evaluated both grossly and histologically after 72 hours of reperfusion. Eleven of the 12 flaps from the VEGF group survived, whereas the survival rate was 6 of 12 and 5 of 12 flaps for the heparin- and saline-treated groups respectively. Flap survival was significantly greater in the VEGF-treated group compared with the heparin- and saline-treated groups (p < 0.025, p < 0.01 respectively). Furthermore, there was no significant difference between the heparin and saline groups. These results indicate that VEGF plays a role in reducing the damage that occurs in ischemia-reperfusion injury, and that the use of VEGF holds promise as a potential therapy for increasing flap survival.
Animals↗
Results of termino-lateral neurorrhaphy to original and adjacent nerves.
In this comprehensive investigation, we studied three different neurorrhaphy models in an attempt to elucidate the potential of termino-lateral nerve repair to original and adjacent nerves. In experimental group 1, the peroneal nerve was sectioned and then attached to the posterior tibial nerve in a termino-lateral fashion. In experiment group 2, the motor nerves to the gastrocnemius muscle were sectioned and then attached to the posterior tibial nerve in a termino-lateral fashion. In experimental group 3, the obturator nerve (L2-4) was sectioned and attached to the sciatic nerve (L4-6) in a termino-lateral fashion. For the control in each group, the same type of nerve used in each respective group was transected without repair. Experimental groups 1 and 2 showed viable axons in the peroneal nerve distal to the neurorrhaphy site. Experimental group 3 showed no viable axons at these sites. No regeneration was observed in the transected nerve without repair in all three control groups. This study suggests that termino-lateral neurorrhaphy is a viable means of repairing damaged nerves if the distal segment of the sectioned nerve is reattached to its original trunk distal to its original branch point. However, the results from experimental group 3 demonstrate that termino-lateral neurorrhaphy cannot be used to repair nerves when the donor and recipient nerves originate from different spinal cord levels.
Anastomosis, Surgical↗
Rat tail replantation as a training model for microvascular procedures of digit replantation.
In this study we sought to evaluate the potential of rat tail replantation as a tool for very-small-vessel microvascular anastomoses. We used 10 adult Sprague-Dawley rats. The tail was completely amputated 2.0-cm distal to the base of the tail. Then the tail was replanted with anastomoses of two superficial dorsal veins from both sides and one artery. All 10 replanted tails were pink, viable, and normal-appearing at all daily inspections performed from the first to the fourteenth postoperative days. This model can provide a training tool for the acquisition of superior microvascular surgical technique for the repair of very small vessels that stimulate digital replantation.
Amputation, Traumatic↗
A new heart failure model in rat by an end-to-side femoral vessel anastomosis.
OBJECTIVE: The aim of this study was to develop a new shunting procedure for producing heart failure in the rat incorporating microvascular techniques and avoiding an abdominal operation. METHOD: We performed an end-to-side anastomosis between the femoral vein and the femoral artery just proximal to their trifurcation into the saphenous, epigastric, and distal femoral vessels. RESULTS: Of the 15 rats which underwent this procedure, six died within 48 h. The nine surviving animals were sacrificed and examined six weeks following surgery. All nine had developed cardiac hypertrophy and cardiac failure. CONCLUSION: This model provides a relatively simple and reproducible means of creating high output heart failure and cardiac hypertrophy in the rat without necessitating abdominal surgery.
Anastomosis, Surgical↗
Molecular studies in flexor tendon wound healing: the role of basic fibroblast growth factor gene expression.
Basic fibroblast growth factor (bFGF) is a cytokine that plays a fundamental role in angiogenesis. This study examines bFGF messenger RNA (mRNA) expression in a rabbit flexor tendon wound healing model. Thirty-four New Zealand white rabbit forepaws underwent transection and repair of the middle digit flexor digitorum profundus tendon in zone II. Tendons were harvested at increasing time intervals and analyzed by in situ hybridization and immunohistochemistry. Few tenocytes and tendon sheath cells expressed bFGF mRNA in unwounded tendons. In contrast, tendons subjected to transection and repair exhibited an increased signal for bFGF mRNA in both resident tenocytes concentrated along the epitenon and infiltrating fibroblasts and inflammatory cells from the tendon sheath. These data demonstrate that (1) normal tenocytes and tendon sheath cells are capable of bFGF production, (2) bFGF mRNA is upregulated in the tendon wound environment, and (3) the upregulation of this angiogenic cytokine occurs in tenocytes as well as in tendon sheath fibroblasts and inflammatory cells.
Animals↗
Effect of hyperbaric oxygen on survival of the composite ear graft in rats.
In this study the authors set out to determine whether postoperative hyperbaric oxygen (HBO) therapy increases the survival rate of the composite graft in the rat ear model. A composite graft (1 x 0.5 cm2) that included skin, subcutaneous tissue, and cartilage was created from the left ear, and was transferred onto the posterior auricular site of the right ear. The animals were divided into two groups: a control group (N = 10) and an experimental group receiving HBO (N = 10). The experimental group was given HBO immediately following reattachment for 4 hours, and then for 6 hours each day for 5 days (2 atm). The results showed the average ear flap survival area in the experimental group was 82%, and it was 26.5% in the control group (p < 0.01). Histology demonstrated the existence of neovascularization in the experimental group. We have concluded that postoperative HBO therapy increases the survival of the rat ear composite graft, and that the effect of this therapy is influenced by the magnitude (size and thickness) of the graft.
Animals↗
Use of 20 cm or longer interposition vein grafts in free flap reconstruction of the trunk.
Between January of 1993 and September of 1995, six microsurgical free tissue transplants were performed using saphenous vein grafts ranging from 20 to 39 cm in length. All six free flaps survived. Two wounds were caused by radiation injury and two by tumor resection. The remaining two free flaps were performed for contour deformity and spinal cord coverage. All of the recipient sites were located on the trunk. In each case, an arteriovenous loop was created before the microvascular anastomosis to the free flap. There was one arterial thrombosis requiring thrombectomy and revision of the anastomosis. Three patients developed minor wound complications that responded to local wound care. Each of the flaps successfully provided wound coverage, and in two cases the flaps tolerated further radiation results. Long interposition vein grafts can be used for difficult microsurgical reconstructive procedures with reliable results when no local recipient vessels are available. Versatility is therefore afforded in placement of the flap and the choice of recipient vessels, making this option a useful one in the treatment of complex wounds of the trunk.
Abdomen↗
Arterialization of the venous system in a rat lower limb model.
Creation of alternative vascular conduits has been one of the most challenging subjects in the history of vascular surgery. In the past, afferent arteriovenous fistulas have been used by vascular surgeons to rescue ischaemic extremities. We have undertaken a comprehensive investigation to characterize arterialization of the venous system at different levels of the rat lower limb. In Group 1 (n = 28), we performed an end-to-end anastomosis between the proximal saphenous artery and the distal saphenous vein (Superficial venous system), and ligated all other branches of the femoral artery. In Group 2 (n = 28), we performed an end-to-end anastomosis between the proximal saphenous artery and the distal femoral vein (Deep venous system). In Group 3 (n = 24), the control group, the femoral artery was ligated proximal to its trifurcation into the saphenous, epigastric, and distal femoral vessels. Group 4 (n = 10), the normal group, underwent no surgery. Animals were sacrificed at the first, third, and eighth postoperative weeks. Arteriographic, India ink injection, latex injection, and histological studies were performed on all groups. Successful arterialization of veins, significant neovascularization, and less ischaemic injury of muscles were noted in the arterialized vein groups (Groups 1 and 2) when compared with the ligated group (Group 3). This model appears to depict successfully arterialization of the lower limb venous system in a small animal model.
Angiography↗
Blood-flow velocity as a factor in postoperative microvascular patency.
The authors attempted to develop a reliable and reproducible new animal model in which the blood-flow velocity to a flap could be varied. This model was utilized to study the effects of different blood-flow velocities on the patency rate of small 1- to 2-mm vessels after common microsurgical procedures. Male Sprague-Dawley rats, weighing 450 to 550 gm, were used to develop a model creating either a "high blood flow" or a "low blood flow" state by ligating the rat femoral artery, either distally or proximally, to an epigastric artery based on a groin cutaneous flap. Blood-flow velocities were measured by microvascular flowmeter, and statistical analysis was performed on the data collected. The model was next used to determine the effects of different blood-flow velocities on the patency rates of rat femoral vessels after primary anastomosis vs interpositional vein grafting. Interpositional vein grafting was subsequently repeated by a more senior microsurgeon, to determine the potential effects of increased surgical experience. The animal model was reliable, easily reproducible, and efficacious in producing two separate groups of rats with significantly different blood-flow velocities (3.98 vs. 2.14 +/- 0.5 ml/min), as was confirmed by electromagnetic flowmeter and statistical analysis. In experienced hands, decreased blood-flow velocity did not result in decreased patency rates of these small vessels after primary anastomosis, or even after vein grafting. As long as microvascular vein grafting and primary anastomosis procedures are done properly, even 1-mm vessels can tolerate significantly decreased blood-flow velocity without a decreased patency rate. Although many known factors can contribute to thrombosis and failure of anastomoses in clinical microsurgery, blood-flow velocity appears not to be a significant factor. Also described is a new, reliable animal model that can be used in small-vessel blood-flow velocity studies.
Anastomosis, Surgical↗
Uncomplicated pregnancy following total bilateral rectus harvest: a case report.
Muscle-sparing rectus abdominis muscle harvest has been advocated to preserve abdominal wall integrity and to reduce postoperative complications and functional loss. In previous cases of pregnancy following single and bilateral rectus muscle harvest, muscle-sparing techniques were used to fortify the abdominal wall. We report a case of uncomplicated gestation and delivery following total bilateral rectus muscle harvest. While abdominal wall strength is greatly affected by rectus harvest, the fascial and tendonous components of the abdominal wall contribute substantial static integrity and elasticity. Careful repair of the donor site makes complete rectus muscle harvest an option even for women contemplating pregnancy.
Adult↗
Comparison of muscle mass preservation in denervated muscle and transplanted muscle flaps after motor and sensory reinnervation and neurotization.
The gracilis muscle model was used either as a denervated muscle in situ or as a transplanted flap in 273 rats to compare the trophic effects of muscle reinnervation and neurotization using sensory and motor nerves. The average gracilis muscle flap weighed 626 +/- 94 mg at the time of the initial procedure. Experimental muscles were examined 6 months following the procedure. In denervated, nontransplanted muscles, both motor nerve reinnervation and neurotization resulted in significantly preserved muscle mass, averaging 570 +/- 69 and 521 +/- 116 mg, respectively, compared with the denervated control average of 178 +/- 22 mg (p < 0.05). Sensory nerve reinnervation and neurotization produced much smaller trophic effects (p > 0.05). In transplanted gracilis free flaps, however, only direct reinnervation with motor or sensory nerves resulted in improved bulk preservation, with average weights of 313 +/- 83 and 327 +/- 91 mg compared with the control average of 201 +/- 76 mg (p < 0.05). Neither sensory nor motor neurotization was significantly effective in the free-flap model (p > 0.05). These data suggest that transplantation may alter the response of muscle to reinnervation.
Animals↗
Gene expression of transforming growth factor beta-1 in rabbit zone II flexor tendon wound healing: evidence for dual mechanisms of repair.
The postoperative outcome of hand flexor tendon repair can be complicated by adhesions between the repair site and surrounding tissue. To date, the biology of hand flexor tendon wound healing remains controversial--both intrinsic (resident tenocyte) and extrinsic (tendon sheath fibroblast and inflammatory cell) processes may contribute to repair. Transforming growth factor beta-1 is a cytokine that plays multiple roles in wound healing but is also implicated in the pathogenesis of excessive scar formation. This study examines the activation of transforming growth factor beta-1 mRNA in a rabbit zone II flexor tendon wound-healing model. Forty New Zealand White rabbit forepaws underwent complete transection and repair of the middle digit flexor digitorum profundus tendon in zone II. Tendons were harvested at increasing time intervals (1, 3, 7, 14, 28, and 56 days) and analyzed by in situ hybridization and immunohistochemistry to determine the expression patterns of transforming growth factor beta-1. A small number of tenocytes exhibited expression of transforming growth factor beta-1 mRNA at baseline in nonwounded control tendon specimens. The surrounding tendon sheath in these control specimens also revealed low numbers of fibroblasts and inflammatory cells expressing transforming growth factor beta-1 mRNA. In contrast, flexor tendons subjected to transection and repair exhibited increased signal for transforming growth factor beta-1 mRNA in both resident tenocytes and infiltrating fibroblasts and inflammatory cells from the tendon sheath. These data demonstrate that (1) normal unwounded tenocytes and tendon sheath cells are capable of transforming growth factor beta-1 production, (2) this cytokine is activated in the tendon wound environment, as evidenced by mRNA upregulation, and (3) the upregulation of this cytokine in both "intrinsic" tenocytes and "extrinsic" tendon sheath fibroblasts and inflammatory cells supports dual mechanisms for tendon repair. Because transforming growth factor beta-1 is thought to contribute to the pathogenesis of excessive scar formation, the findings presented here suggest that perioperative biochemical modulation of transforming growth factor beta-1 levels may help limit flexor tendon adhesion formation.
Animals↗
Rat intercostal nerves as experimental nerve grafts.
In this study, we dissected and measured both sets of intercostal nerves including lengths, diameters, and axon counts in 12 adult rats to provide data applicable to experimental nerve graft research. Dissections showed that total lengths of intercostal nerves from the spinal bifurcation to their last arborizations near the midline ranged from 10 to 89 mm, and diameters ranged from less than 0.1 to 0.5 mm from the thinnest to the thickest part. The segment of easiest dissection was the part between the spinal bifurcation and the lateral cutaneous branch. This part was 4-27 mm (mean, 13.3 mm) long and had an almost constant diameter of 0.18-0.5 mm (mean, 0.32 mm). Counts ranged from 201 to 566 axons/ nerve. The segment proximal to the lateral cutaneous branch was the most convenient part to be harvested as a nerve graft, especially in the 8th to 12th intercostal nerves. These nerves could serve as sources for experimental grafts.
Abdominal Muscles↗
Magnetic resonance imaging detection of vascular occlusion of a pedicled muscle flap.
Contrast-enhanced magnetic resonance imaging (MRI) can be a highly sensitive monitor of tissue blood perfusion. This technique has been used to assess blood flow through liver, kidney, and certain tumors, but has not been widely applied to the study of skeletal muscle circulation. In our study, we used a novel scanning software to obtain contrast-enhanced T2*-weighted gradient echo MRI images of pedicled quadriceps muscle flaps in rabbits in order to study images of arterial, venous, and arterio-venous occlusion. We administered an intravenous bolus of gadoteridol contrast agent at the initiation of scanning, which produces a decrease in T2*-signal and improves the sensitivity of measuring blood perfusion. Within 30 seconds of MRI scanning, control flaps with intact pedicles exhibited a rapid decrease in T2*-signal intensity, indicating adequate perfusion of blood through muscle tissue; however, occluded pedicled flaps showed no significant change in signal intensity, indicating lack of blood perfusion. Differences in signal intensities as measured by MRI between occluded and control flaps were statistically significant (P < 0.05). Selective vascular occlusion of either artery alone, or both artery and vein were detected within 15 minutes, whereas selective venous occlusion could be detected after 2 hours. We conclude that MRI has the ability to assess skeletal muscle perfusion, and is capable of noninvasively evaluating a cross-section of tissue in both superficial and buried flaps. MRI, therefore, may have the potential for evaluating perfusion in muscle flaps (including buried flaps), and other disorders of muscle circulation such as compartment syndrome.
Animals↗
New simplified radio-opaque injection technique for visualization of rat arteries.
We have developed a new and simplified injection technique based on a mixture of latex and lead oxide. This injection technique is unique in its possession of both color and radio-opacity. We have developed and refined this methodology in rats, and have demonstrated it to possess superior qualities of injectability. Depiction of small vessels is highly detailed both radiographically and grossly.
Angiography↗