Coagulation Technique Research Articles

Experimental studies for clinical standardization of transabdominal laparoscopic nephrectomy.

In keeping with the maxim that minimal invasiveness is the present working trend in most areas of surgery, we investigated the possibility of laparoscopically removing a diseased human kidney. Before any actual clinical attempt could be made in this direction, an experimental study was set up in order to determine the most beneficial methods and techniques which would guide us through our first clinical cases. This step-by-step training program consists of: (1) initial familiarization with different laparoscopic instruments, bimanual dissection, ligation and coagulation techniques, camera handling and trocar placement as well as organ retrieval systems using the lap simulator; (2) laparoscopic removal of the kidney and ureter of the pig either as short- or long-term study, and (3) laparoscopic simulation with the lap tent during open surgery.

Government-funding program on reversal of tubal sterilization.

Three hundred and sixty-one women were provided government-funded sterilization reversal services with the technique of microsurgery. A large majority of reasons (89.8%) for requesting reversal surgery was a loss of children, and the mean interval between sterilization and reversal was 28.7 months. Two hundred and seven (69.7%) of 297 follow-up cases have experienced term delivery or intra-uterine pregnancy and 5 cases were ectopic pregnancy. The largest number of reversal clients (63.3%) were sterilized by the laparoscopic unipolar coagulation technique and the next largest group (24.2%) was sterilized by the laparoscopic banding technique. The highest pregnancy rate (77.8%) was shown in clients who had undergone laparoscopic banding technique while the lowest (65.9%) was the group of laparoscopic unipolar coagulation. A more than 60% of the clients became pregnant within 6 months of their reversal surgery, with the shortest interval being 1 month, the longest 39 months, and the mean 7.6 months. A large majority of the successful cases, 81.6%, were pregnant within 1 year of their reversal surgery.

Application of Argon Beam Coagulation in Urological Surgery

Argon beam coagulation is a new form of electrocautery that has proved useful to control diffuse bleeding in other surgical specialties. We report its application to urology. Three cases are presented in which argon beam coagulation provided excellent hemostasis in situations that are often difficult to control, such as partial nephrectomy for penetrating trauma, hemorrhagic cystitis refractory to other forms of treatment and after anterior exenteration for bladder cancer. The basis, technique and advantages of argon beam coagulation are discussed, as well as other instances in urological surgery in which it may have application. Argon beam coagulation is an alternative to conventional methods of hemostasis whenever there is a diffusely bleeding operative site.

Prospective randomised comparison of current coagulation and injection sclerotherapy for the outpatient treatment of haemorrhoids

The feasibility and early results of a new technique of outpatient proctoscopic coagulation of haemorrhoids by means of an electronic probe (Ultroid, Microvasive Inc., USA) were evaluated in comparison to conventional injection sclerotherapy. Age, symptom and sex-matched groups were analysed before and 6 weeks after outpatient treatment, using scoring systems (n = 51). A mean of 6.2 +/- 0.4 ml of phenol in oil were injected over 2.4 +/- 0.2 min compared to a mean current of 15.8 +/- 0.2 mA over a period of 11.9 +/- 0.8 min (p less than 0.001, treatment time). Sclerotherapy was found significantly less tedious than coagulation. More patients complained of discomfort during coagulation, but the difference in tolerance scores between the 2 groups was not significant. Three patients in the coagulation group but none in the injection group refused to be treated by the same method again due to discomfort. Significant benefits were achieved by both modes of treatment after 6 weeks. The early cure rates for bleeding were 84% for sclerotherapy and 64% for coagulation (p = 0.2) and for prolapse 56% and 44% respectively (p = 0.72). Injection sclerotherapy is preferable to Ultroid coagulation for the outpatient treatment of haemorrhoids because it is a quicker, less tedious and more comfortable procedure with equally effective early results.

Experimental radiofrequency (RF) coagulation with computer-based on line monitoring of temperature and power.

The safety and reliability of radiofrequency coagulative techniques are questioned after each coagulation, especially in functional neurosurgery. In spite of the high level of technical development of modern surgical RF generators there is still uncertainty about the character of the coagulative lesion. For the present study, a 500 kHz RF generator was connected through a module for analog/digital conversion and for regulation to a personal computer provided with a software programme for the graphic display in real time of the RF power and of the temperature/time curves. The effects of thermocoagulation were studied in fresh egg white, and monopolar lesions were made in the subcortical white matter of rabbits with a probe with a 0.5 mm diameter and a bare tip of 3 mm in length. The regularity of thermocoagulation depends on the accurate temperature reading at the tip of the electrode. The ideal course of the temperature is a smoothly ascending curve from the level of 37 degrees C to the level present for coagulation, followed by a straight horizontal line. With too slow a response of the probe to temperature changes there is an inherent danger of overheating in the initial phase of the procedure. Additionally the power level has to be adjusted for each probe. On line monitoring with graphic display of the physical parameters provides a direct control of the course of the coagulation. Regular curves of the physical parameters without temperature overshoot correspond to reproducible lesions in vitro and in vivo.

Catheter for endoluminal bipolar electrocoagulation.

An interventional catheter was designed that can induce controlled endoluminal tissue lesions by means of bipolar radio-frequency (RF) electrocoagulation under fluoroscopic guidance. The technique was used to obtain safe and reproducible percutaneous occlusion of the porcine cystic duct by reactive endoluminal scar formation. The new triple-lumen, 7-F, polyethylene catheter contains two insulated active wires and accommodates a 0.038-inch steerable guide wire, which facilitates insertion and placement of the active catheter tip under fluoroscopic control. The coagulation technique is relatively simple and requires only a small, portable bipolar RF generator and ammeter.

Long-term results following argon laser trabeculoplasty

Long-term follow-up findings after argon laser trabeculoplasty are communicated. The coagulation technique employed was that described by Wise and Witter (1979). The circumference of the chamber angle was coagulated over 360 degrees. The indications were chronic open-angle glaucoma, pseudoexfoliation glaucoma, pigmentdispersion glaucoma, glaucoma in aphakia, and glaucoma after ALT or fistulizing surgery with uncontrolled IOP. Glaucoma cases in which IOP exceeded 35 mm Hg were not treated by this method. Therapy was considered successful if a decrease in IOP to below 20 mm Hg was achieved. The difficulties of finding appropriate parameters for the success of glaucoma therapy are discussed. The percentages of normotonic eyes after ALT with a follow-up period of one to four years are reported and compared with results obtained by other authors. After one year, IOP was normal in 89.9% of 881 eyes (chronic open-angle glaucoma 94%, pigment-dispersion glaucoma 91%, pseudoexfoliation glaucoma 86%, glaucoma in aphakia 88%). After two years, it was normal in 72.6% of 237 eyes (chronic open-angle glaucoma 82%, pigment-dispersion glaucoma 50%, pseudoexfoliation glaucoma 53%, glaucoma in aphakia 75%). After three years, it was normal in 60.5% of 76 eyes (chronic open-angle glaucoma 72%, pigment-dispersion glaucoma 25%, pseudoexfoliation glaucoma 37%, glaucoma in aphakia 66%). After four years, it was normal in 95.4% of 128 eyes (chronic open-angle glaucoma 82%, pseudoexfoliation glaucoma 50%). The results of ALT therapy reported by other authors are similar. A decrease in efficiency, initially of 5% to 10% per year, is seen in eyes thus treated, which may necessitate fistulizing surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Vascular thermocoagulation ? perivascular nerve lesions an ultrastructural report on the choice between monopolar and bipolar electrocoagulation

High-frequency coagulation is used with advantage for a number of purposes, including the production of haemostasis during surgery. The morphological changes which thermocoagulation produces in or near the wall of an artery remain, however, largely unknown; and systematic research in the subject is long overdue. As might be expected from clinical experience, the local effects of monopolar thermocoagulation are much more severe and far-reaching than those caused by the bipolar method. For these reasons the bipolar coagulation technique is to be preferred wherever possible.

The Current Technique of Ileoanal Anastomosis

An analysis on 87 cases (54 with familial polyposis and 33 with ulcerative colitis on whom one of the authors (J.U.) has performed ileoanal anastomosis in Tokyo and Hyogo revealed a steady and remarkable improvement of their functional results. The evolutional modifications of the authors operative technique and the current operative technique are described and illustrated in detail. The anorectal mucosa was stripped out with the forceps coagulation technique through the anal canal in the prone jackknife position. The J-shaped ileal pouch, mostly with bilateral blood supplies, was directly anastomosed to the anal sphincteric apparatus, which was excluded by a loop ileostomy for 3 months. For colitis, total colectomy and abdominal ileostomy with open rectal exclusion in principle precede the above operations (the three-staged radical surgery for colitis without a permanent ileostomy).

Function of the diabetic retina after panretinal argon laser coagulation.

Panretinal photocoagulation has been demonstrated to have a beneficial effect on the natural history of diabetic retinopathy. However, it is associated with detectable loss of retinal function. To determine the best coagulation technique we conducted a prospective study in 32 eyes of 16 patients. We investigated retinal function in relation to spot size and scatter density after panretinal laser coagulation. One eye was treated with approximately 400 comparatively large laser spots (0.6-0.8 mm diameter), whereas the fellow eye was coagulated with approximately 1500 small spots (0.2-0.4 mm diameter), so that the total coagulated area was almost the same in both eyes. Subjective parameters (visual acuity, perimetry, dark adaptation, photostress), as well as objective functions (electroretinogram, ERG; electro-oculogram, EOG), were studied preoperatively and then postoperatively over a time span of 6 months. Pronounced impairment of retinal function was detected, which recovered after 3 months on the average. When the pairs of eyes were compared, persistent visual field scotomas as detected by computerized static perimetry, occurred less frequently in eyes subjected to small coagulation spots, although this tendency was not statistically significant.

Veränderungen des Gesichtsfeldes und der Dunkeladaptation nach panretinaler Photokoagulation bei diabetischer Retinopathie

Within the past 5 years panretinal photocoagulation was performed in both eyes of 36 patients (Type I diabetics) with proliferative retinopathy. The age of these patients was between 21 and 38 years. The average follow-up period was 3.6 years. The effects on visual acuity, visual field, and dark adaptation were examined: in 65.3% of the cases (47 eyes) visual acuity remained unchanged; in 34.7% (25 eyes) central visual acuity was reduced. Depending on the coagulation technique and the number of coagulates applied, the visual field narrowed in a more or less pronounced way. Moreover, in all patients the dark adaptation threshold was elevated after panretinal photocoagulation.

Three years' anaesthetic experience with the Groningen Nd YAG laser coagulation technique

The use of the Neodymium YAG Laser technique in the palliative treatment of tracheo-bronchial tumors in 47 patients is described and the merits of the coagulation and anaesthetic techniques are discussed.

German pelviscopy statistics 1978 to 1982

The second statistics concerning pelviscopy in Germany included information about 269603 pelviscopies done in 322 general hospitals and 22859 pelviscopies done in 62 private clinics between 1978 and 1982. The participation of 38.7% for general hospitals and of 43.3% for private clinics may be explained by the fact that a major part of the participating clinics keep no detailed documentation on their operative procedures or cannot answer extensive questionnaires for lack of personnel. In general hospitals the rate of serious complications was 1.9% and in private clinics 2.0%. Injuries of large blood vessels topped the list of the complications (36.3% or 43.2%) (Bisler et al. 1980, Erkrath et al. 1979, Cognat et al. 1976, Mintz 1977). The rate of serious complications occurring in general hospitals and private clinics could certainly be lowered by intensifying the training in pelviscopic operation techniques (e.g. with the training phantom according to Semm) and by avoiding risky procedures like high frequency coagulation techniques in endoscopic operations. The predominant technique employed in tubal sterilisation was the bipolar high-frequency current method with 75% in general hospitals and 73.1% in private clinics, followed by the endocoagulation technique, according to Semm (36.8%). Sterilisation failures were reported in 2.6% or 2.5%. Most failures were reported after sterilisation by the bipolar high-frequency technique (3.9%) followed by clip technique (3.7%), and only very rarely in endocoagulation (1.1%). The rate of ectopic pregnancies following sterilisation was 1.06% = 40.6% of the total pregnancy rate after fallopian tube sterilisation or 0.68%.(ABSTRACT TRUNCATED AT 250 WORDS)

Various coagulation techniques tested in a rabbit model. Results of morphological and endocrinological studies.

CO2- pelviscopies or laparotomies were performed in 370 New Zealand white rabbits and were followed by coagulation of the distal uterine horns with unipolar, bipolar, endo- or CO2-laser coagulation. After 1, 2, 4, 8 or 12 weeks laparotomy was carried out and, following macroscopic description, photo documentation and measurement of the destroyed region, the uterine horns were excised. In addition to the normal histological and electromicroscopic evaluation, 5 mu thick cryostat sections were screened for the presence of nine different enzymes. Attempts were made not only to determine the extent of the destroyed zone, but also to obtain additional information on damage to the vascular and nervous systems of the tubes and ovaries. Progesterone levels were determined in 49 New Zealand rabbits before and after stimulation with 50 I.U. HCG i.v. We were able to show that there is a definite correlation between the type of coagulation technique and the extent of the destruction zone. The average progesterone levels of the animals coagulated using the monopolar high-frequency technique, were significantly lower than the hormone levels in the endocoagulation, bipolar or control group.

False‐Positive Urine Protein Reaction with Cibenzoline, a New Antiarrhythmic Agent

Abstract: Following treatment with cibenzoline, a new antiarrhythmic agent, 23 of 53 patients showed positive proteinuria reactions. In all cases, these results were obtained with bromphenol reagent strips. Subsequent exposure of serial dilutions of cibenzoline to these reagent strips showed positive protein reactions at concentrations as low as 1 mg/ml. Treatment of these same solutions with acetic acid‐sodium acetate heat coagulation technique produced negative findings. Specimens from 14 of the above patients were then retested employing both techniques, and in all cases the reagent strips produced positive results while the heat coagulation technique (or sulfosalicylic acid) produced negative results. Therefore, it appears that cibenzoline produces false‐positive proteinuria results when bromphenol reagent strips are employed for analysis.

Distribution of radioactive 32P in buffaloes' skimmed milk as affected by processing

AbstractThe distribution of phosphorus between the soluble and colloidal phases in buffaloes' skimmed milk, and the effects of five heat treatments on it, was determined by the rennet coagulation technique. The original P in milk and radioactive 32P incorporated into milk, both in vitro and in vivo, were estimated for total and soluble phases by chemical and radioassay methods. The heat treatments consisted of pasteurisation (15 s at 71.8°C), pre‐warming (5 min at 96°C), sterilisation (15 min at 121.5°C), and cooling for 24 h at 4–6 and 0°C. When 32P was added in vitro about 60% remained in the soluble phase; if incorporated in vivo, about 39% was in the soluble phase, while the level of the original P was about 38%. Pasteurisation, pre‐warming and sterilisation progressively decreased the soluble in‐vitro incorporated 32P to about 58, 48 and 34%, respectively. Cooling at 4–6 and 0°C altered the soluble in‐vitro incorporated 32P to approximately 53 and 57%, respectively, from about 64% in the raw milk. On the other hand, changes in partitioning of either in‐vivo incorporated 32P or original P due to any of the five processing treatments were small, non‐uniform and not statistically significant.

Distribution of 45Ca between soluble and colloidal phases of buffaloes' milk as affected by processing

AbstractThe distribution of 45Ca between the soluble and colloidal phases of skimmed buffaloes' milk, and the effects of five processing treatments, was determined by the rennet coagulation technique. The five processing treatments consisted of pasteurisation (at 71.8°C for 15 s), pre‐warming (at 96°C for 5 min), sterilisation (at 121.5°C for 15 min), and cooling (for 24 h at 4–6 and 0°C). The proportion of 45Ca in the soluble phase of raw milk was about 44% (in vitro) and 37% (in vitro), while that of original Ca was about 21% (control). In vitro, pasteurisation, pre‐warming and sterilisation progressively decreased the amount of 45Ca incorporated into the soluble phase to about 39, 31 and 27%, respectively. The decline of incorporated 45Ca was statistically significant (P < 0.01) for the prewarming and sterilisation of milk. In vitro, the decline of incorporated 45Ca or the transfer of 45Ca from the soluble to the colloidal phase due to the heat treatment, was small, irregular and not significant. Changes due to cooling were not significant for any of the experiments. Significantly different results were observed for the partitioning of Ca when comparisons were made between in‐vitro introduced 45Ca and original Ca, and between in‐vivo incorporated 45Ca and original Ca.

Percutaneous radiofrequency facial nerve coagulation in the management of facial spasm.

The authors have developed a fluoroscopy-assisted technique of percutaneous radiofrequency facial nerve coagulation at or near the stylomastoid foramen for management of facial spasm. The details of the procedure and the operative results in the initial series of 27 cases of facial spasm are described. The series included six men and 21 women, aged from 16 to 73 years. Twenty-four patients had classical, intractable, persistent hemifacial spasm, one had an unusual bilateral facial spasm, and one a postparalytic facial spasm. The age of onset varied from 16 years to 70 years. The duration of the symptoms ranged from 3 months to 11 years. Ten patients had undergone previous blunt-needle compression of the facial nerve from one to 10 times. The operative results in the 27 patients have so far been excellent. The longest follow-up has been 1 1/2 years. Although partial facial weakness was present in 60% of the cases, it invariably disappeared within 1 to 4 months. Only three patients experienced recurrence of spasm. In two of them, recurrence followed low-temperature coagulation. The procedure is simple, easy to perform, and extremely effective. It can be performed under local anesthesia in the outpatient clinic.

Surgery in the treatment of retinopathies (author's transl)

Conservative measures for the treatment of affections of retina and choroid are being complemented and expanded upon increasingly by the use of xenon or lasercoagulation. Retinopathies are one of the indications for these microsurgical procedures. The etiology varies, whereas the clinical picture is usually similar. Basic criteria for photocoagulation can be established, but these will be modified considerably by the various coagulation techniques of different surgeons. Personal experiences are compared with accounts featuring in the wide range of available literature.

Chromogenic substrate assays: Present and potential applications

Chromogenic substrates are now available for the study of many aspects of blood coagulation and related enzyme reactions in blood. These substrates have opened up new vistas, including ease of control of routine anticoagulant therapy. The overall impact on routine haemostatic testing will probably be immense since automated systems may be used as an initial screen for patients with haemostasis problems. This applies not only to the coagulation but also for related systems such as the fibrinolytic pathway. The major point one must remember in their use is that activity directed against these substrates may not be identical with the biological activity one wishes to examine. This must make one cautious in their interpretation in the same way as one would be cautious in interpreting the results employing antibodies for antithrombin III levels. A great advantage of chromogen substrate techniques is their accuracy and reproducibility. Some of these points will be illustrated with investigations in our laboratory with the chromogenic substrate S2238. This substrate can assay thrombin formation in a thrombin generation system consisting of recalcified platelet rich plasma. Early in these studies it was shown that S2238 recognized thrombin activity long after the biological activity of the enzyme had disappeared against fibrinogen. The reason for this is because thrombin is inactivated in plasma initially by binding α₂ microglobulin, and that thrombin so bound can still attack S2238. This is a good example of the possible lack of correlation between biologic and substrate activity in certain circumstances. Such property however, would not exclude these agents from being very useful in a general automated screen of clotting problems in large numbers of patients coming through teaching hospitals. One could identify patients with haemostatic problems which might then be investigated by standard coagulation techniques.