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Biomedical subjects

H J Buncke

Publications and source records attributed to H J Buncke.

At least 55 records · Page 3Linked to original sources
PubMed1997

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↗
PubMed1997

DNA amplification determines donor-cell fate in cryopreserved skin allografts.

Cryopreserved donor skin-cell survival was tested after allo- and isotransplantation by DNA amplification of male donor-cell genes which detects trace quantities of cells. Essentially, all cryopreserved allograft skin cells were rejected at the recipient site. Fine-haired, cryopreserved, belly skin of male BALB/c mice was transplanted onto the coarser-haired back of either female Swiss-Webster mice (allograft) or female BALB/c mice (isograft). Six weeks later, skin samples from the graft sites were tested by DNA polymerase chain reaction (PCR) amplification. Although allografts initially engrafted, more than 99.9 percent of male allograft skin cells were subsequently rejected, and gradually replaced by hairless host scar tissue. Clinically, all isografts, including hair follicles, engrafted permanently and maintained donor-cell SRY gene sequences in fine-haired graft site cells. Thus, cryopreservation maintained both the viability and antigenicity of mouse skin cells, because allografts were rejected and isografts survived. Furthermore, DNA amplification, quantified at multiple control dilutions and amplification cycles, can conclusively determine the fate of transplanted cells.

Animals↗
PubMed1997

Using the Internet for rapid exchange of photographs and X-ray images to evaluate potential extremity replantation candidates.

OBJECTIVE: To implement a low-cost system of transmitting high-quality digital photographs of mutilating extremity injuries using the speed of the Internet. DESIGN: A high-resolution digital camera and simple hardware and software platform are used to take and transmit images via electronic mail. The images are received within minutes by the consultant, and an assessment can be made. RESULTS: A low-cost and high-quality system can easily be implemented. Images can be seen by consultants only a few minutes after they are obtained. The quality of the reproductions is excellent, and they are handled exactly as other photographs. CONCLUSION: This technique can be widely applicable and inexpensive to initiate in any emergency room. It allows rapid assessment of extremity injuries and x-ray images by expert consultants, who can then evaluate the replantation or revascularization potential of extremity trauma cases. This can eliminate unnecessary and often expensive transfer of patients who are not candidates for replantation.

Adult↗
PubMed1997

Midgestational sciatic nerve transection in fetal sheep results in absent nerve regeneration and neurogenic muscle atrophy.

In order to test whether fetal nerve healing and regeneration result in complete functional recovery, we transected the sciatic nerve at trunk level in 13 midgestational sheep fetuses. In 10 fetuses immediate microsurgical nerve coaptation was performed. The neonatal lambs were evaluated clinically, electrophysiologically, and histologically. On the transected side, the 10 surviving lambs showed a sensorimotor sciatic nerve paralysis and atrophy of the muscles innervated by the sciatic nerve. Somatosensory evoked potentials were weakly present in 5 animals and absent in 5 animals. Histologically, minimal signs of axonal regeneration, massive degeneration of the entire nerve, and a marked neurogenic muscle atrophy were found. These unexpected results differ from the findings after peripheral nerve transections in late gestational sheep fetuses and also from the classic wallerian degeneration-regeneration pattern that follows adult nerve injury. We speculate that the almost absent regenerative potential at midgestation is related to axotomy-induced neurotrophic factor deprivation during a developmental phase where the neurons are critically dependent on growth factor for survival.

Animals↗
PubMed1997

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↗
PubMed1997

A clinical study of end-to-end versus end-to-side techniques for microvascular anastomosis.

The choice of microvascular anastomotic technique, end-to-end versus end-to-side, is still an item of debate. A review of the literature reveals no difference in patency rates in animal models where there is no size discrepancy. The available clinical evidence stems from Godina's early experience, proclaiming a higher failure rate with end-to-end anastomoses. Factors such as size mismatch and use of injured vessels, rather than anastomotic technique, may have been responsible. This clinical study examines the fate of over 2000 microvascular anastomoses performed in more than 900 tissue transplants. Complications attributable to the anastomosis were considered failures of the anastomosis, were tabulated, and were compared between the two techniques. The end-to-end and end-to-side microvascular techniques were found to be equally effective when properly applied. The choice of technique therefore should be secondary to factors influencing the choice of recipient vessel, such as the condition of the vessel, its accessibility, and the preservation or augmentation of maximal distal flow to an extremity.

Anastomosis, Surgical↗
PubMed1997

Total ear replantation.

Since the first report of successful microsurgical ear replantation in 1980, there have been 12 other cases reported in the English literature. As the number of trained microsurgeons increases, the opportunity to treat the amputated ear with microsurgical techniques should become more common. The reported cases have involved a variety of different mechanisms of injury and methods of treatment. There have been three techniques used to revascularize the amputated ear successfully: primary vascular repair, vein grafting, and use of the superficial temporal vessels as a pedicled vascular leash. Through our own experience and a review of the literature, we have been able to identify certain clinical characteristics that help dictate which technique to use. We report four cases of successful ear replantation, review the various techniques that have been used successfully, and provide treatment recommendations for future consideration.

Adult↗
PubMed1997

Salvage of the severely traumatized lower extremity.

The use of microsurgical techniques has significantly altered the management of lower extremity trauma. Indications for amputation or salvage continue to change, as microsurgical transplants have become more commonplace. Reconstruction of a severely traumatized leg usually involves multiple complicated procedures, each of which can cause its own set of complications. The historically high rate of complications of these procedures and the fact that the resultant limb is never completely normal has led some to the conclusion that severely traumatized limbs should not be salvaged. In order to evaluate our own results in light of these considerations we have reviewed our most recent experience with this difficult problem.

Journal Article↗
PubMed1996

Fibromuscular proliferation in finger arteries after hand replantation: a case report.

We report on a case where a digit of a previously replanted hand was amputated 3 years after injury. Histologically, the finger arteries demonstrated a marked intimal thickening due to fibromuscular proliferation, with narrowing of the lumen. The media showed muscular hyperplasia and fibrosis, whereas the adventitia was normal. These changes are probably a consequence of ischemia and reperfusion injury and might explain the persistent vasomotor insufficiency found in replantation patients.

Adult↗
PubMed1996

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↗
PubMed1996

Application of hemodilution in microsurgical free flap transplantation.

The intra-operative hemodilution and blood auto-transfusion is a blood-saving technique that can be performed when major blood loss is expected. The effects of this technique were studied in 30 microsurgical free flap transplantation patients. Between 400-600 ml blood was collected from the patients before surgery. The patients received dextran, a balanced salt solution, and glucose with the ratio of 3:1 to the collected blood volume, bleeding, and urine before the blood auto-transfusion. There were no significant changes in RBC, HCT, MCV, blood pressure, or heart rate. Of the 30 free flaps, 28 were successful with a 93.3% survival rate. The safety of intra-operative hemodilution and autologous blood transfusion in microsurgery as well as the effect of hemodilution on transplanted flap survival are discussed in this study.

Adult↗
PubMed1996

Effect of anastomosis and geometry of vessel curvature on blood flow velocity and patency in microvessels.

The effect of the geometry of the vessel and the number of anastomoses on the blood flow was studied. Four different shapes of the vessel were constructed by using a 6-cm-long double vein graft model with three anastomoses: (1) an alpha loop, (2) an omega loop, (3) a sigmoid curve, and (4) straight. Blood flow was measured by an ultrasound Doppler flowmeter. The result showed no alternation in blood flow across different geometry and through three patent microanastomoses. However, six out of seven vein grafts were thrombosed at 24 hr postoperative due to vascular kinks. This model demonstrates potential sites of kinking at the dissection end of the femoral artery, the microanastomoses, the side branches of the vein graft, and the adventitial adhesions. This model is recommended to microvascular trainees for the study of kinking and the management of redundant pedicles and vein grafting.

Anastomosis, Surgical↗
PubMed1996

Effect of vein grafting on the survival of microvascularly transplanted muscle flaps.

Since vein grafting is often required during transplantation of free muscle flaps but is associated with a higher failure rate than those flaps transplanted with primary anastomoses, we sought to compare primary repair with the use of vein grafting in an experimental setting. We transplanted the gracilis muscle to the contralateral side in 98 rats using four different methods of vessel repair. In the Control group (n = 28), both femoral vessels were anastomosed primarily. In Experimental Group 1 (n = 25), the femoral artery was anastomosed with an epigastric vein graft and the femoral vein was anastomosed primarily. In Experimental Group 2 (n = 25), the femoral vein was anastomosed with a femoral vein graft and the femoral artery was anastomosed primarily. In Experimental Group 3 (n = 20), both femoral vessels were anastomosed with vein grafts. The Control and Experimental Groups 1-3 survival rates were 89.3, 76.0, 84.0, and 70.0%, respectively; none of the experimental group survival rates was significantly different from that of the control (P < 0.5). This study demonstrates that the use of size-matched, interpositional vein grafts in the arterial or venous pedicle of the rat gracilis muscle flap during transplantation did not significantly decrease flap survival as compared to primary arterial or venous anastomoses. If the observed failure rate persisted with expansion of the study groups to 60-100 animals each, the failure rate of flaps with vein grafts would be significantly lower and comparable to failure rates reported in some clinical series. The large numbers necessary to significantly show this decrease make this model impractical for further studies.

Anastomosis, Surgical↗
PubMed1996

Cigarette smoking, plastic surgery, and microsurgery.

Although tobacco smoking is known to result in coronary heart disease, chronic obstructive pulmonary disease, peripheral vascular disease, cerebrovascular disease, lung cancer, and other smoking cancers, many surgeons believe that smoking also results in impaired wound healing and poor surgical results. Large clinical experiences in several areas of plastic surgery reinforce this suspicion. Procedures that have been noted to be adversely affected by cigarette smoking include rhytidectomy, abdominoplasty, breast reconstruction, free-tissue transfer, and digital replantation. This article reviews the available data, introduces new clinical data, and hypothesizes about the ways in which some procedures are more affected than others.

Aging↗
PubMed1996

Foreign-body sensation following 3M coupler use in the hand.

The 3M microvascular anastomotic coupling device has gained popularity because of its obvious advantages of speed and simplicity. Many reports attest to its safety and efficacy in microsurgery, including two reports on its use in the hand. We present 2 patients in whom the use of the 3M coupling device in the hand resulted in a palpable foreign-body sensation that was unpleasant to the patient and ultimately had to be removed.

Adult↗
PubMed1995

Experimental microvenous thrombosis following anastomosis with a knotted suture.

An experimental model for producing venous thrombosis was developed in end-to-end anastomoses of femoral veins in rats. The anastomoses were performed using a suture (9-0 suture-70 microns needle) with a knot 1 cm from the needle. The knot was formed by making either six or eight half-hitches in one throw of the suture. Vessel patency was assessed through the direct "milking test" at 20 min and 24 hrs. The incidence of thrombosis when using one knot with six half-hitches ranged from 20% to 40% and with eight half-hitches, from 50% to 70%. The incidence of femoral vein thrombosis varied directly with the presence and size of the knot. In this model, thrombosis was induced by exaggerating vessel injuries that may occur when performing routine microvascular anastomoses. This study demonstrates a reproducible thrombogenic model which mimics clinical practice and may be used to study the effects of local and systemic antithrombogenic agents.

Anastomosis, Surgical↗
PubMed1995

Microsurgical research--a personal experience.

The author recounts his 38 years in microsurgical research from the early days of needle and instrument development to the first successful experimental and clinical microvascular transplants. Selected projects are discussed relating to microvascular thrombosis, vascular spasm and various experimental models in the rat, rabbit and rhesus monkey in an anecdotal fashion.

Animals↗