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M P Fried

Publications and source records attributed to M P Fried.

At least 37 records · Page 2Linked to original sources
PubMed1996

Dynamic T1-weighted magnetic resonance imaging of interstitial laser photocoagulation in the liver: observations on in vivo temperature sensitivity.

BACKGROUND AND OBJECTIVE: Magnetic resonance imaging's (MRI) potential to monitor interstitial laser photocoagulation (ILP) has been previously demonstrated and is further tested here with improved spatial and temporal resolution. STUDY DESIGN/MATERIALS AND METHODS: In vivo experiments employed fiber-delivered 1,064 nm light (3.0 W, 150 sec) in six rabbit livers monitored under T1-weighted FSE MRI as 1 image/10 sec and a 3 mm thick 8 cm FOV. Image signal intensities (SI) were compared with temperatures (T) at 7, 10, and 15 mm from the fiber. RESULTS: Data showed 33 degrees C < T < 60 degrees C. SI did not vary inverselinearly with T; changes in the tissue altered the MRI signal interfering with the SI changes due to temperature. CONCLUSION: MRI cannot map SI-derived temperatures over the entire treatment site. The role of MRI's temperature sensitivity must be coordinated with organ- and dose-specific tissue changes.

Animals↗
PubMed1996

Image-guided surgery in a new magnetic resonance suite: preclinical considerations.

Surgical procedures require correct identification of exposed anatomy with concomitant localization amidst contiguous structures. In endoscopic procedures the surgeon is provided a real-time endoscopic view and is prepared with radiologic images. Here we present an overview of a methodology of localization using intraoperatively acquired magnetic resonance (MR) images in preparation for magnetic resonance imaging-guided endoscopic sinus surgery. The methodology centers around a unique prototype imaging device and operating environment. An "open" 0.5 Tesla MR unit has been created that allows complete access to the patient's head and neck while concomitant images are obtained. Illustrative examples of localization technique from cadaver experiments are presented, as well as insights into the host of concerns for anesthesia, equipment, surgical instrumentation, communications, and documentation.

Anesthesia↗
PubMed1996

Image guidance with laser applications.

Image-guided laser surgery is defined, and an outline of its development is provided. Recent advances in radiologic imaging provide added visualization of laser-induced tissue effects. Current research around the world illustrates the power and potential of this technique in both laser and nonlaser applications. Future studies will reveal the actual contribution to laser surgery in otolaryngology.

Animals↗
PubMed1995

Alternative medicine: does it play a role in the management of voice disorders?

Alternative medicine has begun to receive the attention of the legitimate medical community. Recent evidence reveals that 34% of American adults interviewed reported using at least one unconventional therapy during 1994. A 3-month survey of patient inquiries, conducted at The Voice Center, Beth Israel Hospital, Boston, MA, U.S.A. revealed that 41% of patients made inquiries about the potential use of "unconventional approaches" in the management of their voice disorders. Alternative medicine, while largely unproven for efficacy, represents a rapidly growing approach. The present article defines several alternative medical practices, describes their theories and potential impact on the management of voice disorders, and calls for empirical studies to follow. The alternative practices discussed are limited to behavioral therapies such as massage therapy, creative visualization, Alexander, mindfulness, and mediatation.

Complementary Therapies↗
PubMed1994

Comparative cell targeting in vitro using the CO2 laser.

In keeping with current interest in bactericidal effects of lasers to treat localized infection, we examined the effect of CO2 laser light on three bacterial species. Cell monolayers were placed atop filters minimizing the presence of extracellular water. Samples were exposed to irradiance values between 0 and 520 W/cm2 for 0.1 s. Cell survival was determined by colony counts. There was logarithmic killing of the bacteria with increasing irradiance; 90% kill was effected at 180 W/cm2 for Escherichia coli, 350 W/cm2 for Streptococcus mutans, and 250 W/cm2 for Bacillus stearothermophilus. However, standard deviations suggest no significant difference between cell types. Our results show the bactericidal effect of the CO2 laser with no remarkable difference between Gram types. However, substantial cell kill was achieved at relatively low irradiance. Whereas selectivity of damage may not be afforded by the CO2 laser, it may minimize collateral damage.

Carbon Dioxide↗
PubMed1993

Recent advances in lasers in Otolaryngology.

Laser surgery has been an integral part of otolaryngology procedures since first applied to the larynx nearly 20 years ago. New wavelengths and delivery systems are now available that may prove beneficial but also offer stimulating areas of research. Safe and judicious use of these devices is essential. This editorial describes current future applications of lasers in our specialty.

Humans↗
PubMed1992

Comparative study of laser and scalpel nerve transections.

This investigation was designed to compare standard scalpel transections of the tibial branch of the rat sciatic nerve with those performed using either a milliwatt carbon dioxide (CO2) or a potassium titanyl phosphate (KTP/532) laser. Four transection groups consisted of nerves sectioned with (1) scalpel (control), (2) milliwatt CO2 laser, (3) KTP/532 with microscope attachment, and (4) KTP/532 laser with 400-microns bare fiber. Each laser was used with the same parameters: 10 watts, 0.4-mm spot size, and continuous-wave mode. Horseradish peroxidase (HRP) was applied to the proximal stump for 30 min, and the animals were sacrificed 24 h later. Horseradish peroxidase (HRP)-labeled motoneuron cell bodies in the lumbar spinal cord were then counted. The average numbers of labeled neurons in each group were as follows: group I (n = 14) 518, group II (n = 8) 424, group III (n = 8) 351, and group IV (n = 8) 283. The standard deviations were quite large, however. When all laser transections were pooled and compared with paired scalpel transections, we found a significant difference, both by the paired t-test (P = 0.016) and by the Wilcoxon matched-paired test (P = 0.02). We conclude that laser transection significantly diminishes the number of neurons labeled by the retrograde transport of HRP.

Animals↗
PubMed1992

Laser surgery.

Explore the source record for details and available documents.

Humans↗
PubMed1992

Thermal effects on horseradish peroxidase uptake in laser nerve transections.

The authors previously reported that rat tibial nerves transected with CO2 or KTP/532 laser transmit less horseradish peroxidase (HRP) than those transected with a scalpel. This may be due to laser-specific effects or to thermal phenomena that are laser-independent. This study investigated potential thermal effects on the transmission of HRP through the tibial branch of the sciatic nerve in rats. Bilateral nerve transections were performed on 18 animals using a scalpel (control) or an electrocautery device, which simulated the thermal effects produced by lasers. HRP retrograde transport and deposition in the rat spinal cord were analyzed. Thirteen of 15 animals showed a higher number of HRP-labelled neurons on the scalpel side compared to the electrocautery side; a paired student's t test showed a significant difference (P = .028) in the numbers of HRP-stained cell bodies between the control group (x = 687.13 +/- 119.3) and the electrocautery group (x = 388.1 +/- 111.2). In conclusion, reduced HRP uptake in tibial nerves transected with lasers may be in part due to thermal effects produced by the lasers.

Animals↗
PubMed1991

The use of absorbable sutures in laser-assisted microvascular anastomoses.

The efficacy of the laser in performing microvascular anastomoses has been well established in the laboratory using a number of wavelengths. These studies have concluded that laser-assisted microvascular anastomoses are at least comparable to, if not superior to, ordinary suture techniques. The advantages have been the diminished foreign body reaction that occurs as a consequence of using only a few stay sutures to hold the vessels in approximation while the laser bonding is performed, as well as the rapidity of the surgery. We have already shown that absorbable sutures (polyglactin 910) are as efficacious as standard nonabsorbable sutures (nylon) in both arterial and venous microanastomoses. The current study was undertaken to see if the foreign body reaction could be diminished even further by the use of absorbable 10.0 sutures and compare these findings to laser-assisted microvascular anastomoses performed with nonabsorbable sutures. The carbon dioxide milliwatt laser was used to perform laser-assisted microvascular anastomoses in rat femoral arteries and veins. Patency rates and histological response were compared at intervals of 3 days and 1, 2, 4, 8, and 12 weeks postoperatively. Both arterial and venous patency rates were comparable (overall absorbable, 91.2%-52/57; overall nonabsorbable, 87.7%-50/57), as was the degree of inflammation and fibrosis. We conclude that absorbable sutures can be used for laser-assisted microvascular anastomoses and have the potential of allowing healing to occur without any foreign material within the surgical site.

Absorption↗
PubMed1991

Laser resistant stainless steel endotracheal tube: experimental and clinical evaluation.

A fire due to endotracheal tube (ET) ignition is a catastrophic event that may occur during laser surgery of the upper airway, regardless of the wavelength utilized. Although methods exist that permit laser surgery without an ET, this is frequently not feasible. The current investigation was undertaken to evaluate the efficacy of a double-cuffed stainless steel ET, first in the laboratory and subsequently in a clinical setting. Bench testing was performed using CO2 (both standard and milliwatt) and KTP/532 lasers. Only the distal polyvinyl chloride cuffed end of the tube was potentially ignitable, however, the appropriate use of saline to fill the cuffs allowed only for cuff perforation without ignition. Canine testing was performed in 10 animals: 4 dogs were intubated from 3 to 4.5 hours with the laser resistant stainless steel endotracheal tube (LRSS-ET) (Laser-Flex Tracheal Tube; Mallinckrodt Anesthesia Products, St. Louis, MO) and 2 with an aluminum tape wrapped red rubber ET. Visual and histological examination were performed in both groups at 3 and 7 days. Four dogs underwent CO2 laser laryngeal surgery with visual and histological examination performed at 7 days postoperatively. No untoward effects could be demonstrated due to the LRSS-ET. A clinical study was then performed in 24 patients who underwent laser surgery of the upper aerodigestive tract with either a CO2 or KTP/532 laser. In all cases ventilation was adequate, the shaft of the LRSS-ET proved impervious to the laser, and the distal end of the tube protected the tracheobronchial tree safely.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Laser-assisted microvascular anastomosis using CO2 and KTP/532 lasers.

The milliwatt carbon dioxide (CO2) laser has been shown to be an effective device for performing laser-assisted microvascular anastomosis (LAMA) with consistently high patency rates, minimal tissue disruption, and rapid surgical time as well as the potential for reduced inflammation due to fewer foreign bodies (sutures) in the wound. The purpose of this investigation was to determine the feasibility of using the potassium titanyl phosphate (KTP) laser to perform LAMA and to compare it to CO2 LAMA in both arteries and veins. Patency rates, inflammatory response, and course of healing were evaluated through histological analysis. Twenty-eight rats were divided into two groups, which underwent either CO2 or KTP LAMA and then were sacrificed at 3 days, and 1, 2, 4, 8, and 12 weeks postoperatively. Patency rates for arteries and veins were comparable for both wavelengths (CO2: 100% for arteries, 93% for veins; KTP: 93% for arteries, 93% for veins). Histological grading of inflammation and fibrosis showed no significant difference between the two groups. This study demonstrated the efficacy of using the KTP/532 laser in performing LAMA. We found the KTP and CO2 LAMA to have comparable patterns of tissue damage and course of healing. Although this experiment did not investigate the mechanism(s) of tissue welding, our results suggest that successful LAMA may be independent of wavelength.

Anastomosis, Surgical↗
PubMed1990

The efficacy of absorbable suture for microvascular anastomoses.

Although microvascular anastomoses are routinely performed with nonabsorbable sutures, a foreign body reaction can be stimulated that acts as a nidus for inflammation, infection, and possible thrombosis. Absorbable sutures should be able to diminish this reaction. There are sparse data describing the use of absorbable sutures for both arterial and venous anastomoses. This investigation compares standard microvascular anastomotic technique using nonabsorbable 10-0 sutures (nylon) with absorbable 10-0 sutures (polyglactin 910), using a previously reported tubed superficial epigastric flap model in rats. Patency rates and histologic responses are compared at intervals of 3 days and 1, 2, 8 and 12 weeks postoperatively. Arterial and venous patency rates were similar for both materials (overall nonabsorbable, 85.9%; overall absorbable, 84.4%). A somewhat increased inflammatory response was noted in the arterial absorbable group at 1 week and in both the venous and arterial nonabsorbable groups at 8 and 12 weeks postoperatively. The later finding most probably represents the continued presence of the nylon sutures. The incidence of intraluminal thrombosis was greater for nonabsorbable suture, occurring in two arterial and four venous anastomoses, compared with only one absorbable suture venous anastomosis. We conclude that nonabsorbable suture is as efficacious as standard absorbable material in both arterial and venous microanastomoses with the potential benefit of diminished foreign body reaction.

Absorption↗