Anastomosis to the common and proper digital vessels in free flap soft tissue reconstruction of the hand.

OBJECTIVE: This study seeks to demonstrate the safety of anastomosing free flaps to the common or proper digital artery, and to the volar or dorsal digital vein in soft tissue reconstruction of the hand; as well, as to discuss the advantages of this technique. METHODS: Retrospective review of all patients who underwent free flap reconstruction of the hand in two institutions over a period of 5 years. RESULTS: A total of 29 free flaps (9 great toe pulp, 7 anterolateral thigh, 6 second toe pulp, 4 radial artery perforator, 2 partial medial rectus, 1 lateral arm) in 28 patients met our inclusion criteria. All recipient vessels were the proper or common digital artery and the volar or dorsal digital vein. There was one case of venous congestion that resolved with leeching. There was no partial or total loss of any of the flaps. CONCLUSION: Anastomosing soft tissue free flaps to the common or proper digital artery, and the volar or dorsal digital vein is a safe and effective approach with numerous advantages that should be considered in the reconstruction of soft tissue defects of the hand. © 2016 Wiley Periodicals, Inc. Microsurgery, 38:21-25, 2018.

The effect of an implantable Doppler probe on the salvage of microvascular tissue transplants.

One hundred forty-seven flaps in 135 consecutive patients undergoing microvascular transplantation were monitored using a miniature Doppler ultrasonic probe. Using a modification of a technique described previously by Swartz, the probes were secured to the outflow vein of the flap with Vicryl mesh. Twenty instances of thrombosis or spasm were detected in 16 patients, and all flaps were salvaged (100 percent). There were four false positive and no false negative results. This probe allows for safe, continuous monitoring of flap blood flow, which permits the rapid detection and hence rapid treatment of postoperative complications. Our experience suggests that a significant improvement in the salvage rate of microvascular transplants may be attainable with the use of this device.

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.

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.

Mechanical evaluation of anastomotic tension and patency in arteries.

This study quantified arterial anastomotic tension, evaluated subsequent patency rates, and examined the degree of tension reduction with vessel mobilization. The study was divided into two components. In part I, a mechanical analysis was undertaken to evaluate tension, based on the determination of the force required to deflect a cable (vessel) laterally, and its resulting lateral displacement. Six Sprague-Dawley rats with 12 femoral arteries were divided into two subgroups: 1) no mobilization; and 2) axial mobilization by ligation and transection of superficial epigastric and gracilis muscular branches. The tension of femoral arterial anastomoses was calculated in vessels with no segmental defect and with 1.5-, 3-, 4.5-, 6-, and 7.5-mm defects. In part II, patency was evaluated. Fifty-five rats with 110 femoral arteries were divided into two sub-groups as defined in part I: 1) no mobilization; and 2) axial mobilization by ligation and transection of superficial epigastric and gracilis muscular branches. Microvascular anastomoses were performed with no segmental defect and with 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, and 10-mm segmental vessel defects. Patency was evaluated 24 hr postoperatively. Part I of the study revealed that anastomotic tension gradually increased along with an increase in the length of the vessel defect, from 1.9 to 11.34 g in the no-mobilization group and from 1.97 to 8.44 g in the axial-mobilization group. Comparison of tension linear regression coefficient showed a significant difference between the two groups (p < 0.05). In part II of the study, the maximum length of femoral artery defects still able to maintain 100 percent patency of anastomoses was 4 mm (tension approximately 6 g) in the no-mobilization group and 6 mm in the axial-mobilization group (tension approximately 6.48 g). Microanastomotic tension was related to the size of the vessel defect, with increasing tension leading to thrombosis. Axial mobilization significantly reduced the tension in vessels with segmental defects and decreased thrombosis rates.

Microvenous thrombosis rates following anastomosis with vein grafting and a knotted suture.

An experimental microvenous thrombosis model was developed combining vein grafting in femoral vein defects with exaggerated vessel injuries using a knotted suture in the vessel repair. The rat femoral vein grafts were separately subjected to injuries caused by an anastomosis performed with a suture knotted with eight half-hitches at the distal anastomosis (upstream), the proximal anastomosis (downstream), and both anastomotic sites. These groups were compared to vein grafting done with a standard suture. Vessel patency was assessed at 20 min and 24 hr, and the thrombus component was histologically analyzed at 24 hr after the procedures. One hundred percent of control vein grafts were patent at 24 hr. All experimental groups had significantly decreased patency at 24 hr (P < 0.001). Among the experimental groups, knotted suture anastomoses at both anastomoses produced significantly lower patency (13.3%, P < 0.05) than knotted suture anastomoses at distal anastomoses. Histological analyses of thrombosed grafts showed that a large amount of thrombocyte deposition and inflammatory cells were noted at both anastomotic sites in the vein grafts with a knotted suture at the distal anastomosis and in the grafts with a knotted suture at both anastomoses. Thrombocyte deposition and inflammatory cells were seen only at the site of proximal anastomosis when using a knotted suture at the proximal anastomosis site alone. This study demonstrated that quantified microvenous thrombosis can be produced by exaggerating vessel injuries with a knotted suture in a vein graft model. This thrombosis model can be used to study the effects of antithrombogenic agents.

Biodegradation of the polyurethane foam covering of breast implants.

Although it is generally accepted that polyurethane-covered breast implants have decreased the incidence of clinical capsular contracture, there remain many unanswered questions regarding the physical and chemical degradation of the polyurethane foam covering itself. We have systematically studied the fibrous capsule and polyurethane foam recovered from human breast "explants" in an effort to characterize more precisely the biodegradation of polyurethane foam in the human body. Seventy-five freshly retrieved polyurethane-covered implants and surrounding capsule from 47 patients have been analyzed. Capsular tissue from several sampling sites around the surface of the implants was digested in a collagenase solution until foam was recovered or all tissue was digested. Additional samples were fixed in 10% formalin. Scanning electron microscopy was used to look for structural changes in the recovered intact foam and to determine the foam strut widths. Fourier transform IR spectroscopy and x-ray photoelectron spectroscopy were used to analyze the chemical composition of the polyurethane. The formalin-preserved capsule samples were examined histologically for further evidence of foam degradation. Of the 75 prostheses analyzed, 36 (48 percent) were removed because of capsular contracture and 10 (13 percent) because of infection or exposure of the prosthesis. The remaining 29 (39 percent) implants were removed for various other reasons. Visibly intact foam was recovered from 36 (48 percent) prostheses after enzymatic digestion of capsule tissue. There was a progressive decline in the ability to recover intact foam as the total implantation time increased. Scanning electron microscopy revealed fractures and fissures in the foam structure and thinning of the polyurethane struts. The mean strut width of control, unimplanted foam was 49 +/- 1.5 microns (+/- SEM). Retrieved foam from implants which developed capsular contracture and the infected implants had strut widths of 30 +/- 3.1 and 32 +/- 3.1 microns, respectively. In implants removed for other reasons, the polyurethane foam strut width was 41.2 +/- 2.3 microns. Despite an inability to recover visibly intact foam from 39 specimens, standard light microscopy of 37 of these same specimens showed residual polyurethane still present in the capsule. Various degrees of scalloping and fracturing of the foam were seen in the histologic sections. There is convincing evidence by scanning electron microscopy and histology that polyurethane is degrading. It was not possible to quantitate accurately the rate of degradation, but factors such as capsular contracture, infection, and time appear to have a role in the biodegradation of polyurethane in the human body. These relationships require further study.

Purification of the yellow fluorescent protein from Vibrio fischeri and identity of the flavin chromophore.

A low molecular weight protein (approximately 25,000 D) exhibiting a yellow fluorescence emission peaking at approximately 540 nm was isolated from Vibrio fischeri (strain Y-1) and purified to apparent homogeneity. FMN is the chromophore, but it exhibits marked red shifts in both the absorption (lambda max = 380, 460 nm) and the fluorescence emission. When added to purified luciferase from the same strain, which itself catalyzes an emission of blue-green light (lambda max approximately 495 nm), this protein induces a bright yellow luminescence (lambda max approximately 540 nm); this corresponds to the emission of the Y-1 strain in vivo. This yellow bioluminescence emission is thus ascribed to the interaction of these two proteins, and to the excitation of the singlet FMN bound to this fluorescent protein.