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PubMed1998

Laser nerve repair by solid protein band technique. I: identification of optimal laser dose, power, and solder surface area.

Thirty-four tibial nerves in 17 adult male wistar rats were repaired by applying protein bands longitudinally across the nerve join. The bands were then irradiated with a fibre-coupled diode laser (lambda = 810 nm). The relations among the laser weld breaking force, the power, and the solder surface area were investigated, while maintaining a consistent ratio between the total mass of protein solder in a band and total laser energy delivered (the laser energy dose). When this laser energy dose was held constant, the average breaking force of the laser welds irradiated by 72 mW laser output power was weaker than that reached after 90 mW laser radiation. There is a linear relation between the solder breaking force and the solder surface area when band thickness, laser power, and laser dose are unvaried.

Animals↗
PubMed2001

Carotid artery anastomosis with albumin solder and near infrared lasers: a comparative study.

BACKGROUND AND OBJECTIVE: Laser tissue-welding has been used for anastomosis of carotid arteries. During welding, thermal injury sustained by the vessel walls should be minimized to prevent thrombosis. Two different types of lasers were used and effects on tissue damage were studied in vitro and in vivo. STUDY DESIGN/MATERIALS AND METHODS: End-to-end anastomosis of dog carotid arteries (n = 10) was performed by using a human albumin solder (HAS) in conjunction with Nd:YAG or diode lasers (lambda = 1.32 microm and 1.9 microm, respectively). The arteries were evaluated for patency and evidence of histologic injury after 21 days. Another group of arteries was laser soldered in vitro to measure the intimal and adventitial temperatures by using thermocouples. RESULTS: The arteries repaired with the diode laser sustained significantly less thermal damage than those repaired with Nd:YAG laser, both in vitro and in vivo. In particular, the intimal temperature was significantly lower (P < 0.05) for the diode than for the Nd:YAG repairs (approximately 35 degrees C and approximately 50 degrees C, respectively). In the latter group, the patency rate was 75%, but thrombosis occurred in 75% of the specimens at 21 days. All diode anastomoses were patent and thrombosis developed in only 17% of the arteries. CONCLUSION: Use of the diode laser and albumin solders may provide a means to successfully repair carotid arteries with minimal thermal damage.

Anastomosis, Surgical↗
PubMed1993

Some occupational exposures as risk factors for malignant lymphomas.

BACKGROUND: Malignant lymphomas (Hodgkin disease [HD] and non-Hodgkin lymphoma [NHL]) have been subject to several epidemiologic studies and found to be associated with various environmental exposures, especially solvents, wood, and phenoxy herbicides. METHODS: Various determinants for HD and NHL were evaluated in a case-referent study encompassing 31 cases of HD, 93 cases of NHL, and 204 referents, all alive. Information on these determinants, mainly occupational exposures, was obtained by mailed questionnaires. RESULTS: Crude odds ratios were increased for various occupational exposures, i.e., exposures to solvents, pesticides, metal fumes, welding, and fresh wood, and nursing. Further analyses based on logistic regression indicated exposure to phenoxy herbicides and fresh wood among sawmill workers, lumberjacks, and paper pulp workers to be significant risk factors for HD. Welding, working as a lumberjack, nursing, and ex-smoking were associated with a significantly increased risk for NHL. Radiographic examinations were negatively associated with HD, as was office work for NHL. CONCLUSIONS: The results were mainly in agreement with the findings of earlier studies, but diverging associations also appeared.

Adult↗
PubMed2002

Assessment of personal protective equipment use among Midwestern farmers.

BACKGROUND: Personal protective equipment (PPE) is readily available and widely recommended, yet usage among agricultural workers is largely unknown. METHODS: A mail survey of 2,483 farmers in six Midwestern states with telephone follow-up addressed PPE usage related to sun exposure, noise abatement, chain saw usage, welding and metal work, handling of large animals in and out of confinement facilities, feed handling, manure storage facilities, and mixing and applying chemicals. Summary statistics of survey responses were compiled. RESULTS: With the exception of welding masks, PPE usage was low. Farmers were satisfied with availability of PPE through local hardware and farm cooperatives, but the decision to use PPE was personal and influenced little by outside parties. CONCLUSION: PPE usage rates by farmers on Midwestern farms need to be increased. The desire of the individual farmer to reduce risk of personal injury or exposure should be targeted. The most effective venue will be local agricultural extension services.

Agricultural Workers' Diseases↗
PubMed1987

Angioedema and urticaria as acute and late phase reactions to zinc fume exposure, with associated metal fume fever-like symptoms.

IgE-mediated acute and late phase reactions associated with occupational metal fume exposure are rare compared with the more common metal fume fever. The latter is a common acute industrial disease caused by inhalation of oxides of metals, especially zinc. It is a flu-like illness and is thought to be self-limited. This article describes the first case, to my knowledge, of an immediate and a late phase reaction (urticaria and angioedema) to zinc fumes, associated with a metal fume fever-like reaction. Hives and angioedema developed immediately and in a delayed fashion in a 34-year-old man after he had welded zinc at his job. There also was an associated metal fume fever-like reaction. The relationship was proved by a challenge test done at home. The patient has been asymptomatic since using complete protective measures while welding zinc. Possible immunologic mechanisms are discussed.

Adult↗
PubMed2004

Electromagnetic field exposure and health among RF plastic sealer operators.

Operators of RF plastic sealers (RF operators) are an occupational category highly exposed to radiofrequency electromagnetic fields. The aim of the present study was to make an appropriate exposure assessment of RF welding and examine the health status of the operators. In total, 35 RF operators and 37 controls were included. The leakage fields (electric and magnetic field strength) were measured, as well as induced and contact current. Information about welding time and productivity was used to calculate time integrated exposure. A neurophysiological examination and 24 h ECG were also carried out. The participants also had to answer a questionnaire about subjective symptoms. The measurements showed that RF operators were exposed to rather intense electric and magnetic fields. The mean values of the calculated 6 min, spatially averaged E and H field strengths, in line with ICNIRP reference levels, are 107 V/m and 0.24 A/m, respectively. The maximum measured field strengths were 2 kV/m and 1.5 A/m, respectively. The induced current in ankles and wrists varied, depending on the work situation, with a mean value of 101 mA and a maximum measured value of 1 A. In total, 11 out of 46 measured RF plastic sealers exceeded the ICNIRP reference levels. RF operators, especially the ready made clothing workers had a slightly disturbed two-point discrimination ability compared to a control group. A nonsignificant difference between RF operators and controls was found in the prevalence of subjective symptoms, but the time integrated exposure parameters seem to be of importance to the prevalence of some subjective symptoms: fatigue, headaches, and warmth sensations in the hands. Further, RF operators had a significantly lower heart rate (24 h registration) and more episodes of bradycardia compared to controls.

Adult↗
PubMed1991

Sutureless intestinal anastomoses.

Sutureless intestinal anastomoses can be achieved either by compression, where two inverted rings of bowel are compressed by a hollow circular device that subsequently sloughs away and is passed anally, or by the use of tissue glues or laser welding. Compression devices used clinically with success are the Valtrac biofragmentable anastomotic ring, the polypropylene rings described by Rosati and the AKA guns. Glued anastomoses have only been used in animals and seem to be unsafe. However, laser-welded intestinal anastomoses appear highly promising in experimental studies and further development of this technique is warranted.

Adhesives↗
PubMed2003

Non-suture methods of vascular anastomosis.

BACKGROUND: The main aim of performing a vascular anastomosis is to achieve maximal patency rates. An important factor to achieve that goal is to minimize damage to the vessel walls. Sutures inevitably induce vascular wall damage, which influences the healing of the anastomosis. Over time, several alternatives to sutures have become available. METHODS: A Medline literature search was performed to locate English, German and French language articles pertinent to non-suture methods of vascular anastomosis. Manual cross-referencing was also performed and many historical articles were included. RESULTS AND CONCLUSION: The non-suture techniques can be categorized into five groups based on the materials used: rings, clips, adhesives, stents and laser welding. With all these techniques a faster and less traumatic anastomosis can be made compared with sutures. However, each device is associated with technique-related complications. As a consequence, suturing continues to be the standard approach. The disadvantages of the non-suture techniques include: rigidity and a non-compliant anastomosis with rings; toxicity, leakage and aneurysm formation with adhesives; early occlusion with stents; cost, reduced strength in larger-sized vessels and demand for surgical skills with laser welding. Further refinement is needed before widespread adoption of these techniques can occur. Clips, however, may be particularly promising but long-term evaluation is required.

Anastomosis, Surgical↗
PubMed1985

Automated analysis and survival selection of anchorage-dependent cells under normal growth conditions.

An instrument is described that can automatically analyze and select for a subpopulation of anchorage-dependent cells in tissue culture. Cells that label with fluorescently tagged antibodies or demonstrate structural variations are saved from exposure to a destructive high-intensity argon laser beam. The surviving population may then be cloned. The cell selection may occur in a tissue culture plate or in a microflow incubator which is designed to maintain a constant flow of media at 37 degrees C across cells growing on a glass coverslip. This incubator sits on an inverted microscope which focuses the laser beam to a diameter as small as 1 micron. A high-speed computer-controlled two-dimensional stage moves the cells past the beam for analysis, the results of which determine the fate of each cell: whether it is to be destroyed by radiant energy or selected for survival and subsequent proliferation. Another selection strategy performed by the instrument involves growing the cells on a thin, blackened polyester film which can be cut by the argon laser beam. Cells selected for cloning are then circumscribed. The heat of cutting welds the circumscribed film to a plastic coverslip surface or tissue culture chamber bottom. Nonselected cells may be removed by pulling the unattached polyester sheet from the attachment surface. The selected cells remain on polyester film disks welded to the plastic. Selections may be done automatically under computer control or manually by operator direction of stage movements. This instrument extends the art of automated cell selection and analysis to normal cell lines that must maintain cell-substratum contact (anchorage dependence) for differentiated cell function, e.g., neurons, fibroblasts, or kidney cells.

Cell Adhesion↗
PubMed1990

Use of carbon dioxide laser in improving knot security in polyester sutures.

Knot slippage continues to be a serious concern in surgery. This study explored the possibility of improving knot performance by exposing it to radiation from a CO 2 laser. The specimens were mounted in a special device and exposed in a predetermined position for precisely controlled lengths of time. In the first set of experiments, the welding of ends was examined in nylon and polyester sutures. Although the welding was easily achieved, the joint was found brittle and its strength lower than that of a surgical knot. In the next set of experiments, the work was performed at a more fundamental level using oriented, high density, polyester films. The results showed that up to a certain level of exposure the tensile properties did not change, but beyond it a rapid decay took place. Shear tests on polyester sutures twisted together and then exposed to various levels of energy indicated that a bond of maximum strength developed at this exposure. Mersilene sutures of size 3/0 containing a two throw square knot when exposed to energy of this level produced optimal results. The knot strength increased by about 16% (from 13.4 N unexposed to 15.6 N exposed) and the slippage often known to occur in a two-throw knot was completely absent. This work performed under standard atmospheric conditions provided a direction for greatly enhancing the performance of a two-throw knot in terms of both the security and the strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed2003

Laser ureteral anastomosis using intraluminal albumin stent in a porcine model.

BACKGROUND AND OBJECTIVES: We compared ureteral anastomosis using a laser and intraluminal albumin stent with both conventional suturing and laser soldering techniques. STUDY DESIGN/MATERIALS AND METHODS: Twelve pigs underwent bilateral ureteral anastomoses (N = 24) using one of the three anastomotic methods: (1) laser welding with intraluminal albumin stent (N = 11); (2) with albumin solder (N = 8); and (3) conventional suturing (N = 5). Operative parameters, leakage rate, intrapelvic perfusion pressure, urography, and histology of the anastomoses were examined. RESULTS: Operative time for ureteral anastomosis in the stent and solder groups were significantly shorter than the suture group (means 370 seconds and 360 vs. 710 seconds, both P = 0.02). Leakage rate of the anastomoses was lower in the stent group (9%, 1/11) as compared to the solder group (25%, 2/8). The Whitaker test showed that the intrapelvic perfusion pressure elevated gradually after anastomosis and significantly increased at 4 weeks postoperatively in all three methods. Various degrees of hydronephrosis were also noticed in three groups after 4 weeks of surgery. CONCLUSIONS: Use of the intraluminal albumin stent increased the reliability of laser welding for ureteral anastomosis. The clinical significance of using this technique should be investigated further.

Anastomosis, Surgical↗
PubMed2001

Laser-tissue soldering with biodegradable polymer films in vitro: film surface morphology and hydration effects.

BACKGROUND AND OBJECTIVE: Previous research introduced the concept of using biodegradable polymer film reinforcement of a liquid albumin solder for improvement of the tensile strength of repaired incisions in vitro. In this study, the effect of creating small pores in the PLGA films on the weld breaking strength is studied. Additionally, the effect of hydration on the strength of the reinforced welds is investigated. STUDY DESIGN/MATERIALS AND METHODS: A 50%(w/v) bovine serum albumin solder with 0.5 mg/mL Indocyanine Green dye was used to repair an incision in bovine aorta. The solder was coagulated with an 806-nm CW diode laser. A poly(DL-lactic-co-glycolic acid) (PLGA) film was used to reinforce the solder (the controls had solder but no reinforcement). Breaking strengths were measured acutely and after hydration in saline for 1 and 2 days. The data were analyzed by ANOVA (P < 0.05) and multiple comparisons of means were performed using the Newman-Keuls test. RESULTS: The creation of pores in the PLGA films qualitatively improved the film flexibility without having an apparent adverse effect on the breaking strength, while the actual technique of applying the film and solder had more of an effect. The acute maximum average breaking strengths of some of the film reinforced specimens (114.7 g-134.4 g) were significantly higher (P < 0.05) than the acute maximum average breaking strength of the unreinforced control specimens (68.3 g). Film reinforced specimens were shown to have a statistically significantly higher breaking strength than unreinforced controls after 1- and 2-day hydration. CONCLUSIONS: Reinforcement of liquid albumin solders in laser-assisted incision repair appears to have advantages over conventional methods that do not reinforce the cohesive strength of the solder in terms of acute breaking strength and after immersion in moist environments for short periods of time. Using a film with the solder applied to one surface only may be advantageous over other techniques.

Animals↗
PubMed1987

Head and neck applications of the milliwatt laser.

The head and neck surgeon often uses the carbon dioxide laser. With the advent of new instrumentation, the frequency of usage will increase. The CO2 miliwatt laser offers the advantages of tissue welding, as well as cutting and ablation by virtue of the small spot size produced combined with low power output. Potential applications include microvascular and microneural anastomoses. The milliwatt laser can be used endoscopically for tissue resection with a high degree of precision with power densities comparable to current CO2 lasers. Moreover, the milliwatt laser can be applied to otology for cutting and welding of the tympanic membrane, tissue removal, and stapedotomy.

Animals↗
PubMed1988

Plaque-media rewelding with reversible tissue optical property changes during receptive cw Nd:YAG laser exposure.

Laser dosimetry for thermal fusion of plaque-wall separations during laser balloon angioplasty (LBA) is dependent upon the optical properties of the atheromatous arterial wall during one or more exposures to cw Nd:YAG laser radiation. An integrating sphere technique was used to measure relative transmission and reflection continuously during irradiation of human postmortem atheromatous aortic sections. Tissue luminal surface temperature was recorded continuously with a thermographic video imager during repetitive 20-30-sec, 8-15-watt exposure of a 3-mm nominal spot. In all specimens, transmission fell progressively during each exposure by 10-70% of baseline values. This effect was reversible with normalization of transmission during the initial phase of each subsequent exposure. Changes in transmission were inversely related to temperature over a 50-170 degrees C range, whereas relative reflection remained constant. Accompanying reversible transmission changes was the observation that the weld strength of plaque-aortic wall separations was unchanged by repetitive laser welding and tissue separation of individual sections. In conclusion, temperature-dependent reversible optical and physical properties of plaque occur during exposure to 1.06 microns cw laser radiation.

Angioplasty, Balloon↗
PubMed1988

Low-energy CO2 laser intestinal anastomosis: an experimental study.

Intestinal anastomosis was performed in 17 Wistar rats via tissue welding by the low-energy CO2 laser. The postoperative course in the animals studied was uneventful. The integrity of the anastomosis was investigated manometrically, immediately upon completion of the anastomosis as well as 20 days later. Ten additional Wistar rats served as controls in which conventional interrupted one-layer anastomosis was performed. The results show a significant superiority of the intestinal anastomoses that were constructed by means of laser tissue welding. The time to complete the anastomosis was also significantly shorter when laser rather than manual suturing was used. Serial histological examinations for up to 90 days following surgery revealed complete healing and epithelization of the anastomotic site.

Anastomosis, Surgical↗
PubMed1988

Effect of blood bonding on bursting strength of laser-assisted microvascular anastomoses.

This experiment evaluated the influence of blood on the weld strength of laser-assisted microvascular anastomoses (LAMA). Rat femoral arteries were anastomosed end-to-end by either direct laser welding (group I) or by a blood-bonded technique (group II) whereby fresh blood was applied to the vessel edges before laser exposure. Bursting strength was measured at 0, 1, and 24 hours and at 3 and 7 days by infusing methylene blue into the vessel while pressure was monitored. The results showed significantly increased bursting strength in group II compared with group I at 0 hour and 7 days (P less than 0.05). There was a significant increase in bursting strength in group I from 0 hour to 1 hour (P less than 0.05). It is concluded that blood-bonding enhances the early bursting strength of LAMAs and may facilitate arterial wall healing.

Anastomosis, Surgical↗
PubMed1990

Influences of laser pulse duration and anastomotic disruption on laser-assisted microvascular anastomoses (LAMA).

The success rate of laser-assisted microvascular anastomosis (LAMA) can be influenced by many factors, including the parameters of the laser technique used. This study examined the effects of laser pulse duration and the occurrence of anastomotic disruption immediately following first repair attempts on the incidence of aneurysm formation and the patency rate in LAMA. Fifty transected rat femoral arteries in 25 rats were anastomosed with three stay sutures and welded with a CO2 laser at a power of 80 mW. In each rat, the laser was applied in the form of 45 pulses of 0.2 sec duration to one femoral artery (group 1) and in the form of 15 pulses of 0.6 sec duration to the contralateral femoral artery (group 2). Comparison of group 1 with group 2 showed that overall rates of aneurysm formation (30% vs. 17%) and patency rates (92% vs. 96%) did not differ significantly (P less than 0.05) at 3 weeks postoperatively. However, disrupted vessels in both groups had a significantly higher incidence of subsequent aneurysm formation than nondisrupted vessels (54% vs. 0% in group 1, P less than 0.05; 43% vs. 6% in group 2, P less than 0.06; groups 1 and 2 pooled, P less than 0.001). These findings indicate that changes in laser pulse duration such as those tested do not affect the aneurysm and patency rates of LAMA. The results demonstrate, however, that disruption after laser welding plays a significant role in subsequent aneurysm formation.

Anastomosis, Surgical↗
PubMed1997

Recent case histories of food product-metal container interactions using scanning electron microscopy-x-ray microanalysis.

Scanning electron microscopy (SEM) and x-ray microanalysis (EDS) were used to investigate stress corrosion cracking (SCC) in plain tinplate food cans, product discoloration, filiform corrosion, pitting/perforation corrosion, and loss of coating adhesion in enameled food cans. Intergranular SCC of uncoated tinplate occurred in canned pineapple juice. This is a rare occurrence in acid food products. The fracture developed in the can headspace only at the product line/metal interface by an interaction of the detinned metal surface with stress-inducing compounds in the product. Black discoloration of rice granules in the can headspace of a chicken and rice product was caused by the formation of metal sulfides. The source of the metal contamination was traced to metallic dirt in the coating on the tin-free-steel end. Blackening of light tan-colored olives and brine occurred after 1 year of storage in enameled tinplate containers as a result of pitting corrosion at the side seam weld. The cause of the pitting was a defective side seam stripe which failed to protect the weld. A perforation problem occurred at the score line of aluminum-tinplate bimetallic cans. The failure was caused by the high chloride content of the fruit product. Filiform corrosion resulted in perforations that occurred on the outside surfaces of two-piece tin-free steel cans packed with tuna. The cause of the corrosion was related to scratch defects in the exterior coating and the presence of chloride and sulfate cannery residues in the corroded areas. An enamel adhesion failure developed inside two-piece tin-free steel cans that contained mushrooms. Wrinkles in the coating which were introduced during can manufacture were cracked. The fractures were pathways for product-steel interaction which resulted in container failure.

Corrosion↗