bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of Nd:YAG laser in pancreatic resections with duodenal preservation in the dog
Authors: Berlatzky Yacov , Muggia‐Sullam Michael , Munda Rino , Joffe Stephen N.
Published: March 2007

The trend in recent years for treatment of pancreatic carcinoma and occasionally for pancreatitis has been towards total pancreatectomy. The pancreas is also now being harvested for transplantation. Any operative technique that can reduce operating time, blood loss, and associated morbidity and mortality would be of tremendous advantage. The aim of this study was to undertake a total pancreatectomy using the Nd:YAG laser (wavelength 1,060 nm) with a helium neon laser (wavelength 628 nm) incorporated to provide a marker beam. The laser beam was passed into a 400 μm flexible glass fiber enclosed in a 2.5 mm polyethylene cannula, which also served as a conduit for coaxial CO2. The laser was operated in a continuous wave mode, and the fiber exit beam had a divergence of 10°. For photocoagulation and tissue vaporization, peak powers of 50 W were used with 0.5–1 sec pulses. The total pancreatectomy using the Nd:YAG laser was performed in eight dogs, and ten dogs undergoing the conventional operative procedure served as controls. The findings indicate that the Nd:YAG laser could be used effectively and safely. The operating time was considerably diminished (P < 0.01); the number of ligatures used was smaller; blood loss, graft survival, and duodenal viability were similar. The Nd: YAG laser offers a new therapeutic modality in the performance of tedious and often difficult pancreatic surgery.
CO2 laser vaporization for chronic cervicitis
Authors: Rubinstein Eli
Published: March 2007

Chronic cervicitis is the most common disease occurring during the period of greatest sexual activity and reproductivity, and it is the most common gynecologic disease in young women. The disease is a common sequel to normal delivery and one of the main causes of infertility; it also may be precancerous.

All the treated women in the present study exhibited preoperatively severe subjective symptoms for chronic cervicitis, and 32 out of 60 (53%) exhibited colposcopically atypical squamous epithelium. The women were examined 3, 6, and 12 months following laser surgery: 58 (97%) of them reported a decreasing intensity of their symptoms, and colposcopy revealed a normal postlaser transfor‐ mation zone as well as a decreasing edema of cervical epithelium.
Effect of low‐dose argon irradiation on rate of wound closure
Authors: McCaughan James S. , Bethel Bradley H. , Johnston Timothy , Janssen William
Published: March 2007

Four open circular wounds were made on the backs of each of ten guinea pigs by excising approximately 2‐cm areas of full‐thickness skin and subcutaneous tissue. Every 2 or 3 days, one of the four wounds was treated with 2 J/cm2 argon laser, one washed and treated, one only washed, and one receiving no treatment. The area of the remaining open wound was traced on a glass microslide. A tenth guinea pig received the same „treatments”︁ but the laser was not turned on. The wounds receiving different treatments were randomly selected on different guinea pigs. The area of open wound remaining was measured with a planimeter, and the rate of healing was plotted for each. The numbers of days required for 50 and 75% healing were determined. All wounds were coded and the results determined by an independent observer. We found no difference in the rate of healing of any of these wounds and, under these experimental conditions, found no effect on the overall rate of wound healing by low‐dose argon laser exposure.
Toward the ideal treatment for the port wine stain with the argon laser: Better prediction and an “optimal” technique
Authors: Carruth J.A.S. , Shakespeare P.
Published: March 2007

Treatment of the port wine stain with the argon laser still remains more of an art form than a scientific technique. Already, some very satisfactory results are being obtained, and these will be improved by greater accuracy in predicting those patients who will respond well to argon laser therapy and by the development of an optimal treatment technique.
Laser treatment of discoid lupus (case report)
Authors: Henderson Darrell L. , Odom James C.
Published: March 2007

This is a case report of vaporization of the characteristic disfiguring plaques of discoid lupus erythematosis (DLE) with the carbon dioxide laser. This patient had a dramatic clinical and cosmetic improvement. It is suggested that the altered but not vaporized cells that remained were responsible for the retardation of the disease process.
Argon laser treatment of superficial vascular lesions in children
Authors: Hobby Lovic W.
Published: March 2007

The author's experience in the use of the argon laser in the treatment of superficial vascular lesions in children is reviewed. Deteriorating portwine stains, strawberry hemangiomas, other hemangiomas, telangiectasias, and other lesions are discussed. Their natural histories are discussed. Details are given regarding indications for therapy, techniques, and postoperative results.
Argon laser photocoagulation of port wine stain hemangiomas
Authors: Silver Lester
Published: March 2007

A total of 66 patients with port wine stains is reported. All of these were tested and 46 patients treated (80 treatments). Good to excellent results (significant lightening of color and/or smoother texture of skin) was achieved in 74% of tests (0 scar) and in 82% of treatments (4.3% scar). Treatment results correlate well with test spots but vary somewhat as the lesions are not homogenous and skin textures vary. The lowest energy density commensurate with successful treatment should be used to reduce the incidence of scarring. Future methods of manipulating the PWS may make it possible to achieve better results with less scarring. Teenagers fared well in this series, while the problem of successful treatment in the young child remains unsolved.
Possible hazards from irradiation with the carbon dioxide laser
Authors: Walker Neil P. J. , Matthews Julie , Newsom S.W.B.
Published: March 2007

Previous investigators, using relatively high irradiance levels, have been unable to demonstrate viable tissue in the plume during carbon dioxide laser vaporization. Our study was undertaken to reinvestigate this possibility, particularly at the lower irradiance levels that are currently in clinical use. Fresh post‐mortem skin was injected with a known quantity of bacterial spores and vaporized at different levels of irradiance and energy fluence. The plume and splatter were collected and cultured. Spores were found following the vaporization of five of 13 specimens treated at an irradiance of <500 W/cm2, while there were none in the 20 specimens treated at an irradiance of >997 W/cm2. These results show that the widely accepted assumption that the carbon dioxide laser produces a sterile field may be false and that viable particles may be disseminated during vaporization at low irradiance. This may be important when considering the treatment of potentially infectious lesions.
The effect of CO2 laser excision on local tumor recurrence
Authors: Lanzafame Raymond J. , Rogers David W. , Naim John O. , Raul Herrera H. , Defranco Cecelia , Raymond Hinshaw J.
Published: March 2007

This study was undertaken to determine the effect of CO2 laser surgery on the incidence of local recurrence following tumor recurrence and to study the effect of “sterilization” of the operative site on this phenomenon. Sixty Fisher 344 rats were implanted with R323OAC mammary carcinoma. Animals were anesthetized with intraperitoneal pentobarbital, and all tumors were completely excised at 21 days postimplantation.

The animals were randomized into groups of 12 as follows: Group S underwent excision with the scalpel. Group E underwent excision with electrocautery (Bovie, Valley Labs, Boulder, CO). Group L and LV underwent excision with the Sharplan 733 CO2 laser (Laser Industries, Israel) (TEMoo, 125‐mm handpiece, 25‐W continuous wave). Group LV wounds were then “sterilized” by using the laser defocused to a 5‐mm spot size and gently heating the site without producing blanching or charring of the tissues.

Primary tumor size was 2.0 ± 0.5 cm and was similar in all groups. Animals were observed for recurrence for 33 days postoperatively. Mortalities were excluded from analysis. Tumors recurred in 7/9 (78%) in group S, 5/11 (45%) in group E, 4/10 (40%) in group L, and only 1/12 (8%) in group LV. AH results are significant at P<0.05. The CO2 laser is an effective surgical adjunct to reduce local tumor seeding and recurrence. This effect is enhanced by “sterilizing” the surgical site with the defocused laser beam.
Management of vulvar condylomata acuminata with argon laser
Authors: Rotteleur G. , Riboulet J. L. , Vanlerberghe K. , Pollet M. , Lemaire B. , Brunetaud J. M.
Published: March 2007

One hundred and one female patients with vulvar condylomata acuminata were treated with the argon laser. Most were managed under regional or general anesthesia because of the large size and extent of the warts. Ten patients were lost to follow‐up after the first session. Of 91 other patients, 78 (86%) were free of lesions on follow‐up examinations after one or two treatments. The 13 other patients had recurrent lesions: seven patients underwent three laser sessions; four required four sessions, and 2 others required five and six sessions, respectively. These results were comparable with those achieved with the carbon dioxide laser.
The use of the carbon dioxide laser in head and neck lymphangioma
Authors: White Benjamin , Adkins Warren Y.
Published: March 2007

The carbon dioxide laser has been used to treat various lesions of the head and neck, ranging from carcinomas to hemangiomas, and even including tatoos. A search of the literature does not reveal any reports of the carbon dioxide laser being used to treat lymphangioma. This report discusses the efficacy of treating lymphangioma of the air and food passages with the carbon dioxide laser, and presents three patients who have been treated in this fashion—two for palliation and one for cure.
Nd‐YAG laser application in pulmonary and endobronchial lesions
Authors: Kao Shang‐Jyh , Shen Chien‐Yeh , Hsu Kang
Published: March 2007

For recurrent pulmonary bleeding and recanalization of centrally obstructed or stenosed airways, endobronchial Nd‐YAG laser irradiation through fiberoptic bronchoscopy was performed on 25 patients with malignant (n = 21) and benign (n = 4) disease of tracheobronchial lesions under topical anesthesia.

Complete (n = 12) and partial (n = 6) restoration of the airway occurred in all 25 patients after photoresection therapy. For two patients with recurrent bleeding, the therapy resulted in immediate arrest of bleeding. For five patients the therapy resulted in unsuccessful recanalization because of rapidly recurring tumors.

Two patients' conditions were complicated by respiratory insufficiency, one caused by smoke intoxication during laser vaporization and the other caused by tenacious rubberlike fibrinous plaque within a day after laser treatment. There was no mortality or perforation of the tracheobronchial wall after laser irradiation.

Nd‐YAG laser provides an additional tool in the palliative therapy for unresectable, obstructive malignant tumors and a procedure for avoiding extensive surgery in benign lesions.
A study on the possible involvement of nonlinear mechanism of light absorption by HpD with Nd: YAG laser
Authors: Marchesini Renato , Melloni Elsa , Fava Giannino , Pezzoni Gabriella , Savi Giuseppina , Zunino Franco , Docchio Franco
Published: March 2007

The purpose of this study was to investigate whether excitation of porphyrin could be related to nonlinear mechanisms of absorption of porphyrin itself or of the medium in which porphyrin is embedded.

This possibility was proposed as an explanation for results of previous experiments where a Nd:YAG laser was used. An MS‐2 sarcoma transplanted into the hind pad of BALB/c mice was used as the experimental tumor model. Mice were given HpD i.v. (25 mg/kg) 24 h before exposure to light delivered from an IR laser (1,060 nm). Since at dose‐rates ranging between 600 and 1,200 mW/cm2the thermal effect tended to mask the nonlinear effect, the temperature of the limb of mice was kept cold by running water. Irradiation performed under cooling conditions did not show any tumor growth inhibition. Experiments in vitro performed on HT‐29 cells by a continuous wave (CW) or pulsed (Q‐switch) Nd: YAG laser indicated no appreciable difference in DNA synthesis between irradiated and nonirradiated cells.

Our results did not evidence nonlinear mechanisms of absorption by HpD with Nd:YAG laser both in CW and pulsed (nanosecond range) modes.

Whether this effect should occur, in any case it is unlikely to be suitable to induce a photodynamic effect due to its low efficiency. Nd: YAG laser could induce a heating related effect, which can improve the therapeutic efficacy of PDT.
Laryngo‐tracheal laser surgery and general anesthesia
Authors: Thode Susan A.
Published: March 2007

The use of the carbon dioxide laser in treatment of laryngo‐lracheal lesions is extremely effective when combined with general anesthesia. However, the potential for intraoperative complication is increased due to a pathological reduction in the size of the airway and the presence of an endotracheal tube. To avoid the hazard of endotracheal tube ignition, specific techniques are employed.
Mid‐infrared fiber optics
Authors: Fuller Terry A.
Published: March 2007

Fiber optics for carbon dioxide laser surgery have been in developmental research for the past ten years. An up‐to‐date presentation of infrared fiber optics as they pertain to laser surgery is presented. Optical properties such as intrinsic and extrinsic electronic absorption, multiphonon absorption, and scatter mechanisms are discussed. Real‐world considerations for materials selection and fabrication techniques for both crystalline and glassy fiber optics give the reader a perspective regarding the stage of development of these devices. Data are presented indicating transmission ranges and absorption coefficients for both bulk materials and fabricated fiber optics. The conclusions are drawn based on the needs of the clinician as they relate to the degree of existing technology.
Photodynamic therapy: The state of the art
Authors: Carruth J. A. S.
Published: March 2007

Photodynamic therapy is a new and exciting treatment modality for many forms of localised malignant disease. A considerable amount of laboratory and clinical research has been carried out using the tumour sensitiser haematoporphyrin derivative activated by red light at a wavelength of 630 n commonly produced by either an argon/dye laser or a pulsed gold vapour laser. It appears certain mat continuing research will produce better tumour sensitisers activated by different wavelengths of light, but it will be several years before any new drug/light combination is ready for clinical trials.

This paper presents an overview of the current situation and a summary of some of the exciting results that are being obtained in clinical trials throughout the world.
HeNe laser irradiation delivered transcutaneously: Its effect on the sciatic nerve of rats
Authors: Nissan M. , Rochkind S. , Razon N. , Bartal A.
Published: March 2007

For our study of the effect of low energy laser irradiation (LELI) on living tissue we used HeNe laser on rats. The exponential absorption was reaffirmed in the living tissues overlying the sciatic nerve.

An optimal range of energy between 3.5 and 7 J—associated with energy concentration of 4–10 J/cm2 delivered transcutaneously—was found to cause a significant increase in action potential in the sciatic nerve. The effect lasted for more than 8 months after the irradiation session.
Use of the CO2 laser for malignant disease of the oral cavity
Authors: Duncavage James A. , Ossoff Robert H.
Published: March 2007

The CO2 laser has provided the otolaryngologist/head and neck surgeon with a valuable addition in the diagnosis and treatment of malignant disease of the oral cavity. It is also helpful in the treatment of the premalignant clinical leukoplakias of the oral cavity. Carcinoma in situ has been diagnosed and treated successfully with the CO2 laser. The T1 carcinomas of the tongue, floor of mouth, and tonsil can be successfully managed with the CO2 laser. It also offers the patient a relatively painless method of debulking large obstructing tumors. Other advantages of the CO2 laser include hemostasis, precise visualization, and less edema and pain than the conventional techniques.
Clinical report: Laser myocardial revascularization
Authors: Mirhoseini Mahmood , Cayton Mary M. , Shelgikar Suhas , Fisher John C.
Published: March 2007

A significant number of patients with ischemic heart disease are not candidates for coronary artery bypass or percutaneous transluminal angioplasty and do not respond to medical management. This group includes those who have diffuse coronary artery disease, those with poor ventricular function, and those who have had poor results from previous surgery.

Developing a method to directly revascularize the myocardium by creating channels through the ventricular wall has challenged many investigators. Early methods, including needle acupuncture, were successful in the acute phase, but long‐term patency could not be achieved. Closure of the channels was due to fibrosis and scarring.

Experiments in our laboratory demonstrated that myocardial channels, made with the CO2 laser, remained patent up to five years. Histopathologic examination of the channels showed minimal damage to the surrounding cells in the acute phase. Studies at intervals of two months to two years showed patent endothelialized channels, with no evidence of fibrosis. Channels created in the myocardium protected the ventricle against an ischemic event when the left anterior descending branch of the coronary artery was ligated.

Clinical experience with direct myocardial revascularization by CO2 laser indicates it may be a viable method of treating those patients with ischemic heart disease who are not candidates for other forms of management. The treatment and early postoperative follow‐up in one patient are described.
Current laser dentistry
Authors: Goldman Leon , Goldman Bernard , Lieu Neal Van
Published: March 2007

Current laser dentistry since our initial studies in 1964 is reviewed. Three areas are considered: routine dental office practice, tooth restoration, and oral surgery. For tooth restoration and oral surgery, CO2 and neodymium:YAG lasers are used and lasers are used in photodynamic therapy for oral cancer. Dental office practice today is concerned mostly with uncontrolled studies of biostimulation and requires more basic research and controlled clinical studies. The laser industry in the United States should take a more active interest in defining the applications of lasers in dentistry.
Hyperthermic potentiation of photodynamic therapy employing photofrin I and II: Comparison of results using three animal tumor models
Authors: Waldow Stephen M. , Henderson Barbara W. , Dougherty Thomas J.
Published: March 2007

Hyperthermia induced by a microwave source (2,450 MHz) was used alone and in combination with photodynamic therapy (PDT) to treat the SMT‐F, EMT‐6, and RIF animal tumors in vivo. PDT was administered using either Photofrin I or II as the photosensitizer and an argon‐pumped tunable dye laser (630 nm) as the light source. Greater than additive increases in long‐term tumor control were achieved when hyperthermia was given immediately post‐PDT in the SMT‐F and RIF tumor systems. Only additive (or independent) increases in tumor control were achieved when hyperthermia was given immediately before PDT in all these tumor systems and when heat was applied post‐PDT using the EMT‐6 tumor.

In a series of experiments using the SMT‐F tumor, it was observed that decreases in PDT drug or light doses could be offset (in terms of tumor control) by the addition of a subsequent heat treatment. This result, along with others presented, indicates the clinical potential of PDT and hyperthermia as adjuvant cancer modalities.
New techniques for reducing the thermochemical damage in the course of laser surgery
Authors: Armon Eliahu , Laufer Gabriel
Published: March 2007

New techniques were proposed for reducing the damage incurred to living tissues owing to temperature rise induced by surgical lasers. Precooling of the tissue and spatial filtering were evaluated numerically and were shown to be most effective in most surgical procedures. Application of pulse trains was also evaluated numerically and optimal operating conditions were identified.
CO2 laser surgery of intramedullary spinal cord tumors
Authors: Heppner Fritz , Ascher Peter W. , Holzer Peter , Mokry Michael
Published: March 2007

Of a total of 580 patients suffering from expanding spinal disease, 15 cases of intramedullary lesions were dealt with by the use of the CO2 laser. Sharp cutting and precisely controlled depth effect are the advantages that make the CO2 laser very useful for surgery within the spinal cord. In tumors of tough consistency the neoplastic tissue is usually sharply demarcated, in which case the CO2 laser is used for dissection along this borderline, at an output energy of 15–20 W, infocus, continuous wave (CW). In tumors of soft consistency, characterized by a more‐or‐less diffuse zone of invasion—eg, glioblastomas—vaporization [20 W, out‐of‐focus, CW] and removal by ultrasound‐microsuction is recommended. This procedure should advance layer by layer until normal looking tissue is reached. In this way intramedullary tumors may be removed with minimal side effects. The postoperative course involves less pain and less edematous reaction, and the rehabilitation time is shortened compared with conventional surgical treatment. In benign neoplasms long‐term results are good; malignant cases require additional x‐ray treatment and chemotherapy.
Electron microscopy of CO2‐laser‐induced effects in human fibrocartilage
Authors: Whipple Terry L. , Marotta Joseph J. , May Thomas C. , Caspari Richard B. , Meyers John F.
Published: March 2007

Previous reports of effects of CO2 laser energy on human fibrocartilage suggest thermal injury extends to a depth of approximately 70 μm from the target surface with power settings of 35 W and exposure times of 0.5 seconds. The present study was undertaken to look for more subtle evidence of thermal alteration of human fibrocartilage treated with CO2 laser irradiation.

Fifteen human menisci were irradiated at power settings of 10, 20, and 30 W with exposure times of 0.1 and 0.5 seconds. The specimens were immediately fixed and sectioned for electron microscopic examination. Loss of a normal cross banding, and marginal clarity of individual collagen fibers were observed in the extracellular matrix and were observed at distances up to 300 μm from the exposed tissue surface. In addition, cellular changes at similar tissue depth consisted of cell membrane invaginations, clumping of nuclear chromatin, breakdown of endoplasmic reticulum architecture, and loss of mitochondria and Golgi complexes from the cytoplasm were observed.

This study demonstrates deeper penetration of a radiation that was previously appreciated by light microscopy in irradiated human fibrocartilage, although the implications with respect to contraside viability and healing potential of the tissue in vivo is not known.
Acoustic nerve tumor surgery before and since the laser: Comparison of results
Authors: Cerullo Leonard J. , Mkrdichian Edward H.
Published: March 2007

A random computer selection of 21 patients who underwent 28 operations for acoustic neurinoma between 1974 and 1980 using conventional methods, including the operating microscope and microtechnique, was compared with a cohort of 22 patients who underwent 25 operations between 1980 and 1984 utilizing a carbon dioxide laser. Completeness of tumor removal, anatomical and functional preservation of the facial nerve, preservation of hearing, morbidity and mortality, average hospital stay, and eventual outcome were used as markers and were compared. Utilizing P values, the study demonstrated a significantly superior outcome, and as a result a better life quality, in patients who were operated on utilizing a CO2 laser in addition to conventional microsurgical technique.
Examination of tooth pulp following laser beam irradiation
Authors: Serebro Leslie , Segal Trevor , Nordenberg Daniel , Gorfil Colin , Bar‐Lev Moshe
Published: March 2007

An attempt was made to determine the maximum amount of laser energy which could be utilized without impairing pulpal vitality. Forty rat molar teeth were irradiated in vivo; the Sharplan CO2 laser modality, focused to a 0.2‐mm‐diameter spot size was used. The energy output was varied by changing the power and/or the pulse duration. Subsequent histological examination of the irradiated teeth showed that the duration of exposure was more significant than the power. A pulse of 0.2 sec/10 W appears to be the safety limit in preserving pulpal vitality.
Morphological and surface temperature changes in femoral arteries following laser irradiation
Authors: Sorensen Elsie M. B. , Thomsen Sharon , Welch A. J. , Badeau Albert F.
Published: March 2007

A low‐power carbon dioxide laser was to irradiate rat femoral arteries under the same conditions required to anastomose severed human arteries by thermal coagulation. Mean surface temperature changes were measured at the site of laser impact with the artery to evaluate the resultant histopathological changes as a function of laser power. More severe thermal coagulative changes, necrosis, and swelling resulted with increased laser power. Comparison of the temperature‐time relationships showed that the peak surface temperature rise at the surface of these arteries was about 25°C for one pulse at 200 mW laser power, compared to an approximate 7°C rise for one pulse at 120 or 150 mW laser power. Increase in the surface temperature resulted in an increased severity of histopathological injury. These results showed that necrosis of medial layer smooth muscle cells occurred beyond the laser exposure site, suggesting that heat conduction could result in significant damage to reconnected vessel and could be a factor in the formation of a weak bond or an aneurysm.
Pulmonary procedures assisted by optosurgical and electrosurgical devices: Comparison of damage potential
Authors: Locicero Joseph , Frederiksen James W. , Hartz Renee S. , Michaelis Lawrence L.
Published: March 2007

Electrosurgical devices have been used widely in thoracic surgery to assist in dissection and to reduce hemorrhage. Recent experimental data have shown that lasers may be used to resect and control small air leaks while conserving normally functioning lung. This investigation quantitates the amount of damage produced by the electrosurgical unit (ESU), the carbon dioxide laser (CO2), and the neodymium: YAG laser (YAG) compared to standard suture (SU) techniques. Six dogs were anesthetized, intubated, and ventilated. The left chest was opened and the lower lobe exposed, where four sets of lesions were created using each device. All lesions were visually similar to those lesions that would be created for sealing at the time of a pulmonary resection. The lesions were harvested immediately following wounding as well as at 1, 3, and 6 week intervals. They were examined histologically and ranked from least to most damage produced at each interval. A grading system (0–4+) was also devised to compare the injury to simultaneously harvested normal lung. Immediately following injury, histologic ranking was: CO2 (2+), suture (2+), ESU (3+), YAG (4+). By 6 weeks, the suture damage had become minimal and the ranking was: suture (1+), CO2 (2+), YAG (4+), ESU (4+). The ESU consistently produced more extensive damage than any other device. It appears that the most suitable long‐term adjunctive devices to assist in pulmonary surgery are suture and the CO2 laser. The YAG laser may have specific indications in circumstances when significant blood loss may be encountered. ESU usage should be minimized when attempting to preserve functioning lung tissue.
Is an anesthesiologist's presence justified during therapeutic laser endoscopy?
Authors: Lichtiger Monte , Russin David J.
Published: March 2007

Diagnostic endoscopy has generally been done under intravenous sedation. Diazapam and meperidine are the two most frequent drugs used. Even though these drugs produce sedation, analgesia, and amnesia, they do not provide a quiet field. Therapeutic laser endoscopy requires a quiet field. We conclude that an anesthesiologist is needed at the head of the table. Despite the increased cost of the procedure, the anesthesiologist is able to tailor the anesthesia to fit the needs of both the patient and the endoscopist.
Resection of abdominal hollow organs by laser
Authors: Skobelkin Oleg K. , Breckov Eugeny I. , Bashilov Vitaly P. , Korepanov Valentine I. , Litwin Gregory D. , Smoljaninov Michael V. , Malyshev Boris N. , Salyuk Victor A.
Published: March 2007

During a ten‐year period 642 abdominal hollow organ resections have been performed by means of a new, original technique — that is, CO2 laser irradiation combined with specially designed instrumentation. This resulted in a remarkable decrease in postoperative morbidity and mortality. The article describes the laser procedure.
Comparison of the optical transmission properties of pulses and continuous wave light in biological tissue
Authors: LaPlant M. , Parker J. , Stewart B. , Waner M. , Straight R. C.
Published: March 2007

The purpose of this study is to compare the optical transmission of the pulsed gold vapor laser (628 nm) to that of the continuous wave argon‐pumped dye laser (630 nm) in a homogenous tissue model. Gluteal muscle was taken from a rabbit, and sections of varying thicknesses were made. The tissue samples were positioned at the aperture of an integrating sphere. The laser light was passed through an optical attenuator, coupled to a 600‐μm fiber, and then directed onto the surface of the tissue. Transmitted light was collected by the integrating sphere. Light measurements were made with a radiometer. This procedure was repeated for samples of differing thickness using the gold vapor laser as the light source. The identical procedure was performed using the argon‐pumped dye laser. No significant difference was found in percent transmission of light using the gold vapor laser as compared to the argon‐pumped dye laser.
Silver oxide in YAG sclerostomy
Authors: March Wayne F. , Shaver Robert P. , Gherezghiher PhD Tseggai , Nordquist Robert E.
Published: March 2007

YAG sclerostomy is a filtering procedure performed entirely with the neodymium:YAG laser through a goniolens as an alternative to trabeculectomy in the treatment of glaucoma. Extremely large pulse powers have been required in the past to complete the procedure. We found that an injection of silver‐stabilized protein intrasclerally prior to the procedure makes it possible to perform the procedure with low total power.
Hyperthermia from interstitial laser irradiation in normal rat brain
Authors: Elias Zev , Powers Stephen K. , Atstupenas Eliot , Brown J. Tony
Published: March 2007

This study examined both the effect of variations in optical fiber tip and in light wavelength on laser‐induced hyperthermia in rat brain. Normal rat brains were exposed to argon laser light (454–514.5 nm) delivered through an intracerebral end‐emitting (bare‐tipped) or a diffusion‐emitting (sapphire‐tipped) optical fiber probe. Interstitial thermister probes recorded temperatures after thermal equilibration at varying distances from the emitting source. The end‐emitting fiber produced significantly (P < 0.05) higher elevations in tissue temperature than the diffusion‐emitting fiber at the same laser power output. This is due to the smaller surface area (1.2 mm2 versus 7.8 mm2) of the end‐emitting fiber, which results in a greater rate of energy delivery to tissue adjacent to the fiber tip.

Changes in intracerebral temperature measurements were also recorded at similar distances from a diffusion‐emitting fiber at a continuous total laser power output of 150 mW for light wavelengths of 454–514.5 nm, 700 nm, and 750 nm and at a total laser output of 1.1 W for 1,060 nm. Variations in brain tissue temperature with distance from the laser emission source were compared for each laser group with the tissue temperature profile generated by a radiofrequency (wavelength 600–625 m) interstitial probe. Similar temperature changes were found for all visible wavelengths near the probe, suggesting that the thermal response of brain adjacent to an interstitial laser fiber is primarily dependent upon the rate of energy delivery and not upon wavelength. The thermal profile versus distance from the light source depends mostly upon the level of temperature rise near the interstitial laser fiber tip and not the wavelength of laser light used. These results have important implications in interstitial applications of laser for hyperthermia and photochemotherapy.
Thermal injury by laser pulses: Protection by heat shock despite failure to induce heat‐shock response
Authors: Polla B. S. , Anderson R. Rox
Published: March 2007

Pulsed lasers produce a variety of therapeutically useful effects in tissues by thermal mechanisms. In contrast with conventional hyperthermia, pulsed lasers rapidly induce extremely high temperatures confined to small areas within the tissues. It is not established, however, how cellular damage and repair responses differ between conventional and pulsed laser‐induced hyperthermia. We have addressed this question by examining the induction of cellular heat‐shock proteins (HSPs) and protection by heat‐shock response against pulsed laser vs conventional hyperthermia.

Cultured human dermal fibroblasts at confluency were exposed to single 2‐μsec, 10.6‐μm‐wavelength pulses from a pulsed CO2 laser at radiant exposures between 0 and 1.3 J/cm2. Cell monolayers were directly exposed after removal of overlying medium. Positive control for the ability of the cells to synthesize of HSPs was obtained by heating the cells for 20 min in a water bath at 45°C or 47°C. The cultures were then labeled with L‐[35S] methionine (Met), and proteins analyzed by sodium dodecyl sulfate polyacrylamide and two‐dimensional gel electrophoresis 2 hr after exposure. The morphological alterations induced by laser or heat were similar under phase contrast microscopy. Conventional heating induced a heat‐shock response, with the appearance of HSPs 2 hours after heating. In contrast, synthesis of HSPs could not be detected following laser irradiation, even at exposures decreasing both cell viability and incorporation of [35S] Met into cellular protein. Pre‐exposure of cells to temperatures which induced synthesis of HSPs, however, significantly decreased cell death induced by subsequent laser irradiation.

These data provide insight into the biological events induced by pulsed lasers at the cellular level. Synthesis of HSPs, although not induced by brief laser pulses, may play a role in protection against laser‐induced cell injury.
Measurement of the optical and thermal properties of biliary calculi using pulsed photothermal radiometry
Authors: Long Frederick H. , Nishioka Norman S. , Deutsch Thomas F.
Published: March 2007

The optical absorption coefficients for biliary calculi are important in understanding the mechanism of laser‐induced stone fragmentation. However, the heterogeneous composition of calculi and difficulties in producing optically thin samples prevent conventional spectrophotometric measurement techniqus from being used. To overcome these limitations, we used a pulsed photothermal radiometry system to measure the optical absorption coefficients and thermal diffusivities of various biliary calculi. In the wavelength range examined (350–1,060 nm), there was strong optical absorption which was greater for pigment stones than for cholesterol stones. The data support the theory that the initiation of the plasma accompanying laser fragmentation of calculi is a thermal process.
Characteristic autofluorescence for cancer diagnosis and its origin
Authors: Yuanlong Yang , Yanming Ye , Fuming Li , Yufen Li , Paozhong Ma
Published: March 2007

The autofluorescence spectra of human tissues excited with the 365‐nm line of pulsed xenon ion laser have been measured. The autofluorescence spectra of cancer tissues usually show characteristic peaks near 630 nm and 690 nm, which do not appear in the spectra of the corresponding normal tissues. This characteristic fluorescence can be taken as a criterion for cancer diagnosis; a consistency of 89% with the traditional biopsy method has been obtained in preliminary clinical application to the diagnosis of buccal carcinoma. Spectroscopic investigations suggest that the porphyrin compounds localized and retained in cancer tissues might be responsible for this characteristic autofluorescence.
Superpulse CO2 laser treatment of facial syringomata
Authors: Apfelberg David B. , Maser Morton R. , Lash Harvey , White David N. , Cosman Bard
Published: March 2007

Eight patients with facial syringomata have been treated with the superpulse 2 laser and followed for periods up to 3 years. Superpulse capability allows satisfactory photovaporization of overlying skin and exposure and liberation of the underlying cyst. Healing was satisfactory with minimal scarring and no persistence or recurrence of syringomata in five of eight cases.
Effect of pulse duration on selective ablation of atherosclerotic plaque by 480‐ to 490‐nanometer laser radiation
Authors: Lamuraglia Glenn M. , Murray Steve , Anderson R. Rox , Prince Martin R.
Published: March 2007

The effect of varying pulse duration on selective ablation of human arterial plaque was evaluated by measuring ablation thresholds and ablation efficiencies on fresh human fibrofatty plaque, calcified plaque, normal intima, deep media, and adventitia using 480‐ to 490‐nm laser radiation at 1, 8, and 50‐μsec pulse durations. For all tissues examined, the ablation threshold energy increased with increasing pulse duration, but the threshold for normal tissue ablation was approximately twice that of plaque at all pulse durations. Ablation efficiency was studied at a fluence that was twice the ablation threshold for plaque. For those fluences, normal intima had detectable ablation only at 50 μsec. The ablation efficiency of fibrofatty plaque was minimally reduced with prolongation of pulse duration; however, there was a substantial decrease in the ablation efficiency of calcified plaque when the pulse duration was lengthened from 8 to 50 μsec. These data show significant selective ablation of fibrofatty and calcified plaque at 1, 8, and 50 μsec and suggest that the optimal pulse width for selective ablation of all plaque in the 480‐ to 490‐waveband is less than 50 μsec.
Laser balloon angioplasty: Effect of tissue temperature on weld strength of human postmortem intima‐media separations
Authors: Jenkins Ronald D. , Sinclair I. Nigel , Anand Raj , Kalil Arthur G. , Schoen Frederick J. , Spears J. Richard
Published: March 2007

Dehiscence of portions of atheromatous plaques fractured during percutaneous transluminal coronary angioplasty may contribute to both abrupt reclosure and gradual restenosis. Laser balloon angioplasty has been shown to be effective in welding human plaque‐arterial wall separations in vitro by heating tissues with a Nd:YAG laser during balloon inflation. To define the potentially useful therapeutic range of tissue temperature required to achieve thermal welds, 220 1‐cm diameter discs of human postmortem atheromatous aortic tissue, the intimal plaque of which had been separated from the media, were exposed to 3–25 watts of Nd:YAG laser radiation delivered over a 12‐mm2 nominal spot size for 20 seconds via a 400‐μm core optical fiber. As measured with a thermistor, adventitial temperature reflected the temperature at the plaque‐media junction to within 10°C. The degree of tissue temperature elevation was related to delivered energy, while effective tissue penetration increased to maximum depth of 3 mm at the highest power density. Strength of tissue welds was defined as the force required to shear opposing layers of welded segments. Adventitial tissue temperatures below 80°C were not associated with appreciable welds, while equilibrium temperatures between 95°C and 140°C were consistently associated with effective mean weld strengths, which increased linearly from 25 to 110 g, respectively. Temperatures greater than 150°C were associated with rapid tissue dehydration and charring. These data suggest that the therapeutic range of tissue temperature that provides effective thermal fusion of intima‐media separations is broad and that the depth and degree of thermal coagulation can be controlled by manipulation of laser energy delivery.
Spectroscopic characterization of cardiovascular tissue
Authors: Clarke R. H. , Isner J. M. , Gauthier T. , Nakagawa K. , Cerio F. , Hanlon E. , Gaffney E. , Rouse E. , DeJesus S.
Published: March 2007

We present results of a series of laser spectroscopic measurements on in vitro samples of cardiovascular tissue. These include laser Raman scattering, Fourier transform infrared, plasma emission and fluorescence, and electron paramagnetic resonance spectroscopy. The results of these spectroscopic measurements are discussed in terms of their implications for the field of laser angioplasty.
Pulsed CO2 laser tissue ablation: Effect of tissue type and pulse duration on thermal damage
Authors: Walsh. Joseph T. , Flotte Thomas J. , Anderson R. Rox , Deutsch Thomas F.
Published: March 2007

Tissue removal by infrared lasers is accompanied by thermal damage to nonablated tissue. The extent of thermal damage can be controlled by a choice of laser wavelength, irradiance, and exposure duration. The effect of exposure duration has been studied in vivo by using CO2 lasers with pulse widths that vary from 2 μsec to 50 msec. Pulse widths of 50 msec, typical of a shuttered, continuous‐wave CO2 laser, produce damage regions 750 μm wide in normal guinea pig skin; the use of a 2‐μseclong pulse reduced this damage zone to as little as 50 μm. Using 2‐μseclong pulses, in vitro studies showed that the minimum zone of thermal damage varied significantly with tissue type. The thermal denaturation of these tissues has been studied and correlated with damage. The effect of denaturation temperature and pulse duration on the width of the damage zone is explained by a simple model.
Comparison of continuous‐wave, chop‐wave, and super pulse laser wounds
Authors: Lanzafame Raymond J. , Naim John O. , Rogers David W. , Hinshaw J. Raymond
Published: March 2007

Some of the latest generation of CO2 lasers incorporate features that alter the wave form. The present study was undertaken to evaluate the relative zone of coagulation in acute laser wounds created in continuous‐wave (CW), chop‐wave (CPW), and super pulse wave (SPW) modes. The damage from single‐point impact sites and incisions was compared in a guinea pig model. Animals were anesthetized with pentobarbital, and wounds were created with a 125‐mm handpiece in focus (0.2‐mm spot size) on dorsal and flank skin sites with the Sharplan 743 and 1100 CO2 lasers (Sharplan, Ltd., Allendale, NJ). Point impacts of CW and CPW were compared at power levels of 5, 10, 25, 40, 60, and 80 W at time durations of 0.05, 0.1, 0.2, and 0.5 seconds. Incisions of 3.0 cm were created at 25 W in CW, CPW, and SPW modes. Histologic sections stained with hematoxylin and eosin and Van Giesen elastin stains were evaluated by a single observer (R.J.L.). Zones of coagulation for the point‐impact study varied from 79 to 257 ± 66 (SD) μm in width with no significant differences between any of the wounds. Greater thermal damage (coagulation) occurred as the time interval increased. The zones of coagulation in the incision study were 309 ± 83 (SD) μm for CW, 238 ± 51 (SD) μm for SPW1 (743), 260 ± 79 (SD) μm for CPW, and 194 ± 56 (SD) μm for SPW2 (1100). These results are significant to the P<0.01 level. The effects of wave chopping are minimal for point impacts, but there is significantly less damage along incisions made with chop wave mode. Super pulse produces a narrower zone of coagulation than does either CW or CPW. The width of the zone of coagulation is greater along the incision than from single‐point CW of CPW impacts.
532‐nanometer green laser beam treatment of superficial varicosities of the lower extremities
Authors: Smith Teruko , Apfelberg David B. , Maser M. Richard , Lash Harvey , White David N.
Published: March 2007

Green laser light at 532 nm was utilized in an attempt to thrombose and blanch superficial varicosities of the lower extremity in 14 patients. Selective vascular damage with sparing of overlying skin was the theoretical rationale for use of green light. Seven of the 14 patients achieved satisfactory results (total or near‐total obliteration of vessels without scarring) after a 6‐month period of observation.
Experimental ab interno sclerotomies using a pulsed‐dye laser
Authors: Latina M. , Goode S. , de Kater A. W. , Long F. H. , Deutsch T. F. , Epstein D. L.
Published: March 2007

We studied the use of a short‐pulse, flashlamp‐pumped dye laser, emitting at 666 nm, to create ab interno sclerotomies in cynomolgus monkeys using a fiberoptic delivery system. Because of the low optical absorption of the sclera in the visible portion of the spectrum, ablation of sclera by continuous wave lasers emitting in this region requires high energies and produces significant thermal damage to surrounding tissues. To enhance the optical absorption of sclera, methylene blue dye was applied iontophoretically; patent sclerotomies were obtained in all 10 eyes of six cynomologus monkeys, with energies ranging from 15 to 50 mj/pulse. Thermal damage to the adjacent sclera was confined to 300 μ/m. Complications included mild intraoperative hyphema at all pulse energies and iridodialysis at higher pulse energies. Filtration blebs routinely failed within 7 days; the use of 5‐fluorouracil postoperatively significantly prolonged bleb duration. The small incision technique described allows ab interno sclerotomies to be created with low pulse energies without the need for conjunctival dissection, thereby avoiding the problems associated with conjunctival wounds. An advantage of this technique is that it can be modified to create ab interno sclerotomies noninvasively by delivering pulsed visible radiation through the cornea with a gonioscopic‐slitlamp system.