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Biomedical subjects

R D Tucker

Publications and source records attributed to R D Tucker.

At least 19 recordsLinked to original sources
PubMed1995

Laparoscopic electrosurgical complications and their prevention.

Insulation failures, direct coupling, and capacitive coupling around active electrodes may cause serious burns and tissue damage to patients undergoing laparoscopic procedures. A coordinated team effort between perioperative nurses and surgeons can prevent life-threatening complications from laparoscopic electrosurgical procedures. Knowledge of the biophysics of electrosurgery, the mechanisms of electrosurgery complications, and prevention of patient injuries will empower surgical team members to provide quality outcomes for patients undergoing laparoscopic procedures.

Adult↗
PubMed1995

Tissue actions of bipolar scissors compared with monopolar devices.

OBJECTIVES: To establish whether bipolar scissors offer equivalent cutting performance compared with monopolar scissors and to compare extent of thermal coagulation injury using two electrosurgical generators. DESIGN: Eighteen female rabbits' uterine horns were cut using controlled velocity at several different wattages with either bipolar or monopolar scissors. The specimens were examined microscopically and zones of thermal necrosis were measured using a stage micrometer against a 1 mm standard. RESULTS: Bipolar scissors cut equally well compared with monopolar scissors and showed significantly less thermal injury. When coupled to a constant voltage generator both the bipolar and monopolar scissors performed better. CONCLUSION: Bipolar scissors offer the surgeon significant safety advantages and equivalent or better performance compared with monopolar scissors when used for laparoscopic surgery.

Animals↗
PubMed1995

Laparoscopic electrosurgical injuries: survey results and their implications.

This article provides the results of a survey on electrosurgical complications and surgical techniques during laparoscopy from the American College of Surgeons. Of the respondents, 18% stated that they had personally experienced an electrosurgical burn to their patient during laparoscopy. The survey shows that the majority of surgeons, 74%, employ coagulation mode most commonly during surgery. Of the surgeons, more than one third routinely employ high-voltage coagulation and blend mode operation at power settings > 40 W. We discuss the possible complications that may occur from high-voltage-high-power settings, such as direct coupling, insulation failure, and capacitive coupling of unintended current into internal tissue such as bowel. We further describe techniques that may be employed to minimize the likelihood of unintended electrosurgical burns as well as technologies that can eliminate or greatly decrease the likelihood of electrosurgical complications.

Burns, Electric↗
PubMed1994

Unrecognized hazards of surgical electrodes passed through metal suction-irrigation devices.

Surgical electrodes, passed through metal suction-irrigation devices, pose significant risks for unrecognized visceral burns through capacitively coupled current using monopolar electrosurgery. Plastic cannulas (and reducers) should be avoided with the metal suction-irrigation electrode; an all-metal trocar cannula confers limited safety. With surgeon education and advances in engineering, the potential for unrecognized visceral injury with capacitive coupling can be eliminated.

Burns↗
PubMed1993

Bipolar electrosurgical devices.

The authors point out the safety benefits of bipolar electrosurgical devices as opposed to monopolar. They describe the working principles of bipolar endoscopic coagulators, polyp snares, biopsy probes and papillotomes and laparoscopic forceps, hooks and scissors and deal with their specific functional and safety requirements. The use of bipolar devices is advocated, particularly in view of the anticipated increase in litigation costs.

Electric Conductivity↗
PubMed1992

Education and engineering solutions for potential problems with laparoscopic monopolar electrosurgery.

The potential problems of monopolar electrosurgery relate to unrecognized energy transfer ("stray current") outside the view of the laparoscope. Mechanisms of stray current and unrecognized tissue injury include: (1) insulation breaks in electrodes; (2) capacitive coupling, or induced currents through the intact insulation of the active electrode to surrounding cannulas or other instruments; and (3) direct coupling (or unintended contact) between the active electrode and other metal instruments or cannulas within the abdomen. Capacitive coupling poses the greatest risk for injury when the outer conductor (trocar cannula or irrigation cannula) is electrically isolated from the abdominal wall by a plastic nonconductor. Capacitive coupling is increased by the coagulation mode (versus cut), open circuit (versus tissue contact with the electrode), 5-mm cannulas (versus 11 mm), and higher voltage generators. The safety of electrosurgery can be enhanced by surgical education regarding the biophysics of radio frequency electrical energy, technical choices in instruments using all-metal cannula systems, and engineering developments with a dynamically monitored system for insulation failure and capacitive coupling.

Electric Conductivity↗
PubMed1992

The effect of interstitial hyperthermia on the Dunning prostate tumor model.

The effect of hyperthermia was examined on the Dunning prostate tumor model in rats. Hyperthermia was created by heating self-regulating interstitial seeds with an external oscillating magnetic field. The seed alloy was comprised of 70% nickel and 30% copper. One treatment with 50C seeds for two hours did not provide significant delay in tumor growth compared to controls. However, regimens with two treatments separated by either 48 hours or one week did cause significant delay (p = 0.0013 and p = 0.0096, respectively). These results suggest that an interstitial hyperthermia seed may provide an efficacious outpatient therapy for prostate cancer. Further, interstitial hyperthermia may be readily combined with existing radiotherapy with interstitial gold coated seeds to provide additive or synergistic anti-tumor effects.

Adenocarcinoma↗
PubMed1991

The in vivo effect of regional hyperthermia on dunning R3327 prostatic tumor.

This report describes the in vivo effect of regional hyperthermia on male Copenhagen rats implanted with Dunning R3327 prostatic carcinoma. In six rats, a 22-gauge 1.5-cm needle was inserted into the tumor and heated to 46.5 degrees C for 2 hr. Two hyperthermia treatments were administered 48 hr apart. In a separate group of six rats, the needle was inserted into the tumor, but not heated. After treatment, serial measurements of tumor volume and body weight were made twice a week for 4 weeks. From the first day of measurement to day 22, the tumor size in the treated group compared to control was significantly smaller, P = 0.02. In the first 12 days following treatment, the mean value of body weight in the treated and control groups decreased 7% and 3%, respectively. Following this, body weights increased to baseline levels by the end of the study. No other side effects related to hyperthermia were observed and no immediate mortality occurred. In the control group, two rats died from lung metastasis of the prostatic carcinoma after day 22. In the treated group, no lung metastases were found and no rats died before being sacrificed on day 29. Our experiments show that local elevation of the temperature of the Dunning tumor results in the death of tumor cells; at 46.5 degrees C for 2 hr there is marked tumor damage while the rats tolerated the hyperthermia well.

Adenocarcinoma↗
PubMed1991

The interaction of electrosurgical bipolar forceps and generators on an animal model of fallopian tube sterilization.

Electrosurgical tubal sterilization with bipolar forceps has shown a variable and, in certain studies, a high failure rate. Some physicians have questioned if failure rates are due to an incompatibility between bipolar forceps and bipolar generators of different manufacturers. This manuscript presents data on tissue desiccations performed on a rat uterine horn model that uses two bipolar forceps of quite different designs and two popular bipolar generators. The data demonstrate that if an appropriate amount of energy, between 100 and 117 J, is applied to the tissue, consistent destruction occurs, regardless of the generator-forceps combination used. Histologic examination of the desiccated uterine horns displayed complete occlusion of all samples 8 weeks after the procedure. However, immediately and at 3 weeks after the procedure patent uterine horns were found. In the patent samples most samples displayed considerable electrosurgical damage.

Animals↗
PubMed1991

Do surgical gloves protect staff during electrosurgical procedures?

Fifteen pair of commercially available gloves were tested under conditions that occur during radio frequency electrosurgery to determine their potential to cause burns or shocks. Two pair of gloves showed a hydration effect that produced sufficiently low direct current resistance, 1500 and 5000 ohms, to be a potential shock or burn hazard. All intact gloves passed in excess of 0.75 A of radio frequency current by capacitive coupling. Eleven pair of gloves displayed dielectric breakdown of the latex or neoprene at voltages between 2200 and 2600 volts; the remaining gloves ranged from 5800 to 7000 volts. Under specific conditions all gloves tested have the potential to cause burns or shocks to the surgeon during electrosurgical procedures. To avoid burns, shocks, or glove perforation, surgeons should be aware of situations that put them at high risk.

Burns↗
PubMed1990

In vivo effect of 5 French bipolar and monopolar electrosurgical probes on the porcine bladder.

Previous in vitro studies have indicated bipolar electrosurgical probes would electrodesiccate tissue in a normal saline solution. This study applies similar sized monopolar and bipolar electrosurgical probes to porcine bladder in order to compare each probe's effect in vivo. The power delivered by each probe was calculated; the width and depth of the porcine bladder damage was measured and the volume of the damage calculated. The animals were sacrificed at 24, 48 and 96 h post-procedure so that the amount of tissue destruction could be quantitated relative to the bladder's natural tissue reaction. The data shows the power (watts) delivered by the monopolar probe to be approximately six times that of the bipolar probe. Likewise, the area of bladder wall damage was larger with monopolar at all time periods sampled and showed significant differences at 24 and 48 h. These studies indicate that in viable bladder, tissue bipolar probes will electrodessicate at a lower power and with less shortterm tissue damage.

Animals↗
PubMed1990

Use of 5F bipolar electrosurgical probe in endoscopic urological procedures.

Experimental data have shown bipolar electrodes to function in saline solution with less volume and depth of tissue destruction compared to similar sized monopolar electrodes. We applied the same bipolar generator and electrodes used in laboratory testing in 41 procedures on 36 patients to determine if the bipolar electrode will provide clinically adequate hemostasis. The bipolar electrode was used for bladder fulguration in 37 procedures and ureteral fulguration in 4. The procedures were performed by 7 urological surgeons and in normal saline solution. The bipolar electrode was believed to perform as well as the standard monopolar probe in 39 procedures. The 2 failures included 1 bladder tumor fulguration and 1 electroincision of a ureterointestinal anastomotic stricture. There were no episodes of recurrent bleeding after any procedure. The bipolar system has the added advantage of not requiring a return electrode (ground pad), thereby eliminating the possibility of skin burns.

Ambulatory Surgical Procedures↗
PubMed1990

In vivo evaluation of monopolar versus bipolar electrosurgical polypectomy snares.

The energy required and tissue damage in bipolar and monopolar polypectomy snares were compared in a canine model. The bipolar snare required an average of 34 joules of energy, whereas the monopolar snare required 228 joules to cut the same diameter of gastric mucosa tended into a polypoid structure (p = 0.0005). The reduced energy delivered to the tissue from the bipolar procedure resulted in only 32% average depth of damage to the underlying gastric wall, whereas the monopolar procedure caused an average 69% (p = 0.001). Surgically created polyps required 247 joules and 69 joules for corresponding monopolar and bipolar polypectomy (p = 0.001). The decreased energy required and the correspondingly reduced damage caused to the underlying bowel wall by the bipolar snare should reduce the incidence of perforation and post-polypectomy syndrome. The bipolar snare completes a local circuit about the snare, eliminating the return electrode and, consequently, the possibility of any return electrode burns. The bipolar snare thus provides an added safety margin during polypectomy.

Animals↗
PubMed1989

Management of benign ureteral structures: open surgical repair or endoscopic dilation?

We reviewed 20 cases of ureteral strictures, 15 of which were secondary to ureteral trauma. Of the patients 6 were managed initially by open repair and 14 underwent endoscopic manipulation. All 6 open repairs were successful, compared to 9 of the 14 patients who underwent endoscopic dilation of the ureteral stricture. Of the 5 failures 3 were due to the inability to cannulate the strictured ureter with a guide wire and 2 failed to respond to balloon dilation. Of these 5 patients 4 were treated successfully by an open operation. There were no serious intraoperative or postoperative complications. The average hospitalization was less for the endoscopic group (2.1 days) compared to the open surgical group (8.3 days). Followup ranged from 6 to 48 months.

Adult↗
PubMed1989

A comparison of urologic application of bipolar versus monopolar five French electrosurgical probes.

Urologic endoscopic procedures often involve electrosurgery. Recently bipolar probes have become commercially available. This study compares monopolar and bipolar electrosurgical probes in relation to power losses in urologic endoscopic instruments with the infusion of sterile water and saline, and the power transmitted by probes to tissue correlated to tissue destruction in each fluid. The power losses through each instrument in both solutions were minimal. The bipolar electrode functioned at a much lower power output than did the monopolar electrode. The bipolar probe was also more effective in saline than sterile water. The depth, width and volume of tissue damage for both electrodes were found to vary with generator power output. The data shows the burns had similar diameters for both probes but the bipolar probe caused significantly less burn depth than the monopolar probe. These initial studies indicate that bipolar electrodes can function in normal saline with less depth damage compared to the monopolar probe.

Animals↗
PubMed1984

Survival rates in undifferentiated small-cell carcinoma of the bronchus. A review and 2 case reports.

Patients with inoperable undifferentiated small-cell (oat cell) carcinoma of the bronchus rarely survive for long. The number of long-term survivors has always been variable and treatments given to them have differed markedly. In this article we present 2 patients who have survived for 6 1/2 years and 10 years respectively. These are the only patients surviving beyond 5 years out of 311 patients treated over a 30-year period. The literature on survival of patients with this type of carcinoma is reviewed.

Adult↗