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Biomedical subjects

M G Munro

Publications and source records attributed to M G Munro.

At least 19 recordsLinked to original sources
PubMed2007

Can we achieve international agreement on terminologies and definitions used to describe abnormalities of menstrual bleeding?

BACKGROUND: There is considerable worldwide confusion in the use of terminologies and definitions around the symptom of abnormal uterine bleeding (AUB), and these are leading increasingly to difficulties in setting up multinational clinical trials and in interpreting the results of studies undertaken in single centres. An international initiative was established to develop an agreement process to recommend clear, simple terminologies and definitions with the potential for wide acceptance. METHODS: After widespread consultation with relevant international and national organizations, journal editors and individuals, a modified Delphi process was developed to assess the current use of terminologies followed by a structured face-to-face meeting of 35 clinicians (mostly gynaecologists) and scientists in Washington. Focused small group discussions led to plenary assessment of concepts and recommendations using an electronic keypad voting system. RESULTS: There was almost universal agreement that poorly defined terms of classical origin used in differing ways in the English medical language should be discarded and that these should be replaced by simple, descriptive terms with clear definitions which have the potential to be understood by health professional and patient alike and which can be translated into most languages. The major recommendations were to replace terms such as menorrhagia, metrorrhagia, hypermenorrhoea and dysfunctional uterine bleeding. Suggestions for potentially suitable replacement terms and definitions are made. CONCLUSIONS: A simple terminology has been recommended for the description and definition of symptoms and signs of AUB. This manuscript should be a living document and should be part of an ongoing process with international medical and community debate. Classification of causes, investigations and cultural and quality of life issues should be part of the ongoing process.

Delphi Technique↗
PubMed2001

Gas and air embolization during hysteroscopic electrosurgical vaporization: comparison of gas generation using bipolar and monopolar electrodes in an experimental model.

STUDY OBJECTIVE: To compare the composition of gases generated by bipolar hysteroscopic vaporizing electrodes using electrolyte-rich medium (normal saline) with those of monopolar vaporizing electrodes using nonelectrolytic medium (1.5% glycine). DESIGN: In vitro study (Canadian Task Force classification II-1). SETTING: Laboratory. INTERVENTION: Fresh morbid bovine cardiac muscle was fully immersed in normal saline for the bipolar vaporizing electrode and 1.5% glycine for the monopolar vaporizing electrode. Standard hysteroscopic electrodes were activated at usual and maximum power outputs from radiofrequency electrosurgical generators appropriate for each system. The gases generated were captured and analyzed by gas chromatography and fast Fourier transform. MEASUREMENTS AND MAIN RESULTS: Gaseous by-products of electrosurgical vaporization of test tissues largely consisted of hydrogen, carbon monoxide, and carbon dioxide. The composition of gases generated by hysteroscopic monopolar and bipolar electrodes in this laboratory model appear to be similar. CONCLUSION: These gases are all highly soluble in serum. This observation suggests that emboli of gaseous by-products of electrosurgery are unlikely to have an adverse impact on patients. On the other hand, air emboli, largely composed of relatively insoluble nitrogen, are more likely to result in clinically significant cardiopulmonary events.

Animals↗
PubMed2001

Dysfunctional uterine bleeding: advances in diagnosis and treatment.

Dysfunctional uterine bleeding occurs during the reproductive years unrelated to structural uterine abnormalities. Ovulatory dysfunctional uterine bleeding occurs secondary to defects in local endometrial hemostasis; while anovulatory dysfunctional uterine bleeding is a systemic disorder, occurring secondary to endocrinologic, neurochemical, or pharmacologic mechanisms. Evaluation of patients with abnormal uterine bleeding and identifying those with dysfunctional uterine bleeding is achieved with a combination of the following: history; physical examination; and judicious use of laboratory evaluation, endometrial sampling and uterine imaging, with sonographic techniques and/or hysteroscopy. Coagulopathies should be considered as should the notion that intramural and subserosal myomas are unlikely to contribute to AUB. High-quality evidence suggests that medical therapy is frequently successful, and newer approaches, such as local delivery of progestins via intrauterine devices, appear to be particularly promising and devoid of systemic side effects. For those intolerant of medical therapy, and/or for whom fertility is no longer desired, a number of minimally invasive surgical options for hysterectomy now exist and are collectively termed endometrial ablation. Endometrial ablation may be performed with or without hysteroscopic guidance. There is an increasing body of evidence that suggests that nonhysteroscopic endometrial ablation may be at least as effective as hysteroscopic endometrial ablation, even when the hysteroscopic procedure is performed by experts.

Female↗
PubMed2000

Medical management of abnormal uterine bleeding.

Abnormal uterine bleeding occurs secondary to a wide variety of functional and structural abnormalities. Although there is clearly a place for surgery, medical therapy has enormous potential for most women, especially those with dysfunctional uterine bleeding. To provide women with appropriate options for therapy, the clinician must be prepared to distinguish abnormal bleeding that is associated with ovulation from that which is anovulatory and to use appropriate ancillary tests to identify structural and endocrinologic anomalies or lifestyle factors that may explain the bleeding. In undertaking such an investigation, it is important for the clinician to be able to distinguish lesions that may be asymptomatic and unrelated to the bleeding from those that truly are the source of the problem. With this information, a rationally determined set of medical and, if appropriate, surgical therapeutic options may be presented to the woman. Among these medical treatment options are a number of treatment options that have not seen widespread use in North America but are inexpensive, effective, and well tolerated. It is clear that medical therapy is not for everyone. Women deserve the opportunity to relieve their symptoms with nonsurgical options.

Androgens↗
PubMed1999

Incision characteristics associated with six laparoscopic trocar-cannula systems: a randomized, observer-blinded comparison.

OBJECTIVE: Laparoscopic trocar-cannula systems of different design but similar internal diameter result in incisions of varying dimensions. Such variations might affect the incidence of incisional complications, such as dehiscence and hernia. We developed a system to measure associated fascial defects and then used the techniques to compare the defects resulting from different trocar-cannula systems. METHODS: This was a randomized, observer-blinded study. Six laparoscopic trocar-cannula systems of similar diameter (12 mm) were tested (two pyramidal, two blunt conical, and two cutting-dilating) using a white swine model. All systems were inserted into each of 12 subjects, with location designated by random allotment (total 72 insertions). The fascial defects were exposed and then directly measured for incisional length and area by an observer blinded to the system used. Means of each outcome variable (incisional length and area) were compared using factorial analysis of variance. RESULTS: The values for mean incisional areas were as follows: cutting-dilating 28.73 mm2 and 31.09 mm2, pyramidal 18.25 mm2 and 26.75 mm2, and blunt conical 10.00 mm2 and 12.33 mm2. Mean maximal incisional lengths were similar among all trocar-cannula systems. CONCLUSION: Blunt conical trocar-cannula systems resulted in significantly smaller fascial defects compared with the widely used pyramidal and the two cutting-dilating trocar-cannula systems tested. These differences have potential clinical implications. For example, smaller fascial defects could reduce risk of incisional hernia and dehiscence.

Animals↗
PubMed1999

Entry force and intra-abdominal pressure associated with six laparoscopic trocar-cannula systems: a randomized comparison.

OBJECTIVE: In trocar-cannula systems, increased entry force could result in loss of operator control, a potential cause of serious visceral and vascular injuries. We developed a system to measure entry force and intraperitoneal pressure to evaluate and compare trocar-cannula systems. METHODS: Six laparoscopic trocar-cannula systems of similar diameter (12 mm) were tested (two pyramidal, two cutting-dilating, and two blunt conical) using a white swine model. All six systems were inserted into each of 12 subjects with location designated by random allotment (72 insertions). During each insertion, intraperitoneal pressure and entry force were measured using a system consisting of a gas-gas transducer, a 50-lb load cell, and a multichannel data acquisition board. Mean entry force and intraperitoneal pressure were compared using mixed-model analysis of variance. RESULTS: Mean entry force measurements were as follows: pyramidal 9.01 lb and 13.48 lb, cutting-dilating 9.94 lb and 16.46 lb, and blunt conical 19.15 lb and 31.91 lb. Intraperitoneal pressure changes generally reflected measured entry force. CONCLUSION: The system successfully measured both entry force and resultant intraperitoneal pressure. Pyramidal trocar-cannula systems required the lowest force for entry. These differences in entry force have potential clinical implications related to the risk of visceral and vascular injury. Intraperitoneal pressure measurement could be used as a surrogate for insertional force measurement.

Abdomen↗
PubMed1998

Endometrial ablation versus hysterectomy: STOP-DUB.

Dysfunctional uterine bleeding (DUB) is a common clinical condition that frequently leads to hysterectomy. Endometrial ablation --a "minimally invasive" surgical technique that removes or destroys the endometrial lining of the uterus -- is a conservative alternative to hysterectomy for DUB. While endometrial ablation has lower immediate costs and shorter recovery than hysterectomy, symptoms are not always resolved. Available data from studies with admittedly incomplete follow-up suggest that up to one quarter of patients treated with endometrial ablation require repeat ablation or subsequent hysterectomy to stop DUB. This suggests that the short-term advantages of endometrial ablation may be offset by possible longer-term disadvantages. The Surgical Treatments Outcomes Project for Dysfunctional Uterine Bleeding (STOP-DUB) is a randomized trial designed to compare endometrial ablation against hysterectomy. The primary outcomes address issues of importance to women, such as quality of life and resolution of symptoms that led to surgery. Other outcomes include subsequent surgery and cost-effectiveness of the procedures. The study's target enrollment is 800 women--400 in each treatment group -- from 20 clinical centers throughout the US. The women will be followed for 2 years after surgery. Part of the STOP-DUB is a parallel observational study that involves women who do not choose surgery or who are not eligible for the randomized trial but could become eligible with time. It is anticipated that the result of this research will provide important information to women and their health care professionals as they consider the relative merits of surgical treatments for DUB.

Catheter Ablation↗
PubMed1997

Supracervical hysterectomy: ... a time for reappraisal.

Supracervical or subtotal hysterectomy is a procedure that largely was discarded in the middle part of this century. This decision was made because of the reduction in morbidity and mortality associated with total hysterectomy, the only known and available method for the prevention of cervical cancer. This rationale, appropriate earlier in the century, has become somewhat undermined with the advent of Papanicolaou smear screening, colposcopic diagnosis, and simple outpatient therapy for preinvasive cervical neoplasia. Furthermore, some have argued that supracervical hysterectomy better preserves bladder and sexual function, and may be associated with reduced surgical and postoperative morbidity. Recently, laparoscopic supracervical hysterectomy has been introduced as another operative alternative with putative advantages over the procedure performed via laparotomy. However, for routine cases, the available literature does not confirm that one procedure is superior, regardless of the route of access. In selected cases, where benign conditions significantly distort the cervical anatomy complicating the dissection, supracervical hysterectomy would seem a prudent choice. It is clear that appropriately designed comparative studies are in order, to better determine the place for supracervical hysterectomy in the contemporary management of women with benign uterine disease.

Cervix Uteri↗
PubMed1996

Loop electrosurgical excision in the peritoneal cavity. Preliminary experience with the rat model.

OBJECTIVE: To evaluate a monopolar electrosurgical loop electrode designed for use at laparoscopy. STUDY DESIGN: A pilot, observational study of cutting effectiveness followed by a nonrandomized comparative study of thermal injury associated with the loop electrode and CO2 vaporization in the rat model. The observer evaluating thermal injury was blind to the energy source used. RESULTS: The loops cut most effectively with a continuous, sinusoidal, radiofrequency output at 40 W. The depth of coagulative necrosis was similar in the laser vaporization and loop excision groups of lesions when using outputs and power densities commonly attainable at laparoscopy. There was more necrotic debris in the lasered lesions. CONCLUSION: While a randomized comparison will be necessary to clarify these results, electrosurgical loop electrodes seem to have a role in a number of gynecologic laparoscopic procedures.

Animals↗
PubMed1995

Loop electrosurgical excision with a laparoscopic electrode and carbon dioxide laser vaporization: comparison of thermal injury characteristics in the rat uterine horn.

OBJECTIVE: Our purpose was to compare the thermal intraperitoneal injury in lesions resulting from a monopolar electrosurgical loop electrode designed for laparoscopic surgery with similar lesions fashioned by carbon dioxide laser vaporization. STUDY DESIGN: A randomized, observer-blinded comparison was made of histopathologically measured thermal injury in rat uterine horns. The primary outcome measure was the depth of necrotic debris and coagulative necrosis in the lesions created by the two methods. RESULTS: The depth of coagulative necrosis was similar in the laser vaporization (0.118 +/- 0.028 mm) and the loop excision groups (0.165 +/- 0.167 mm). However, the average amount of necrotic debris was greater in the lasered lesions (0.053 +/- 0.019 mm) compared with those made with the loop electrode (0.013 +/- 0.011 mm). CONCLUSIONS: The depth of coagulative necrosis in rat uterine lesions fashioned with a loop electrode is similar to that of lesions created by carbon dioxide vaporization at power densities comparable with those usually achieved at laparoscopic surgery. There is a greater amount of necrotic debris in the lasered lesions. This suggests that electrosurgical loops designed for laparoscopic surgery may have promise for the cost-effective excision of intraperitoneal tissue.

Analysis of Variance↗
PubMed1995

Review on laparoscopic hysterectomy.

An increasing number of data on laparoscopic hysterectomy has become available since the procedure was introduced in 1989. This article reviews all published series till June 1995, totaling 4502 cases. Prior to this procedural evaluating strategy is addressed to highlight the short-comings of such a review. Most data are collected retrospectively in a lunited number of centers, all dedicated to the procedure. Laparoscopy Assisted Vaginal Hysterectomy (LAVH) may cover a whole range of procedures, and a classification system is needed. It is suggested that classification systems based on the degree of anatomical dissection is clinically most relevant. During 76.1% of LAVH-procedures, the uterine artery is ligated laparoscopically, though the fraction of total laparoscopic hysterectomies is minimal (1.5%). Mean conversion rate is 2.5% and mean major complication rate is 3.24% (range 0-20%). Urinary tract lesions (1.42%), such as bladder perforation, and reintervention for haemorrhage (0.78%), are the most frequent complications. LAVH seems an efficacious procedure, more data on its effectiveness are urgently needed.

Female↗