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Biomedical subjects

Malcolm G Munro

Publications and source records attributed to Malcolm G Munro.

At least 19 recordsLinked to original sources

Management of leiomyomas: is there a panacea in Pandora's box?

New procedures and medications continue to be developed for the treatment of women with uterine leiomyomas; however, most are not adequately evaluated, and none is applicable in all circumstances. Appropriate management of uterine leiomyomas should be individualized, considering the related symptoms, as well as the number, size, and location of the tumors and the patient's desire regarding uterine conservation.

Embolization, Therapeutic↗

Oral medroxyprogesterone acetate and combination oral contraceptives for acute uterine bleeding: a randomized controlled trial.

OBJECTIVE: To compare the efficacy of multidose medroxyprogesterone acetate and a multidose monophasic combined oral contraceptive (OC) for hemodynamically stable women with nongestational, acute uterine bleeding. METHODS: Hemodynamically stable patients with acute uterine bleeding sufficient to justify immediate medical or surgical intervention were enrolled in an open-label, randomized trial comparing oral medroxyprogesterone acetate 20 mg and a monophasic combination OC containing 1 mg norethindrone and 35 mug of ethinyl estradiol, each administered three times per day. Doses were reduced after 1 week to 20 mg per day and one tablet per day for the next 3 weeks for the medroxyprogesterone acetate and OC groups, respectively. Following baseline assessment, patients completed daily treatment and symptom logs collected at 14 and 28 days after initiation of therapy. RESULTS: Forty patients were randomly assigned, 20 in each group; 33 were evaluated at the 14-day visit. Emergency surgical procedures were avoided in 100% of those women taking medroxyprogesterone acetate and 95% of the OC group. Cessation of bleeding had occurred in 88% of the OC group and 76% of those receiving medroxyprogesterone acetate, with a median time to bleeding cessation of 3 days for both groups. Compliance with therapy was higher in the medroxyprogesterone acetate group than the OC group, but there was no overall difference in the incidence of treatment-related nausea and bloating. CONCLUSION: This randomized trial is limited by sample size but suggests that both regimens may be effective and reasonably well tolerated. CLINICAL TRIAL REGISTRATION: Current Clinical Trials (clinicaltrials.gov, www.clinicaltrials.gov) Identifier: NCT00350480 LEVEL OF EVIDENCE: II-1.

Adult↗

The evolution of uterine surgery.

Although described in antiquity, the real dawn of uterine surgery was in the mid-19th century when hysterectomy was occasionally performed vaginally, usually for cancer or prolapse. Then, as now, women experienced symptoms of bleeding and pain emanating from the uterus, and when severe and debilitating, brave surgeons and patients sometimes explored hysterectomy as an alternative. Abdominal hysterectomy mortality rates in the mid-1850s were extremely high, but reduced drastically in the early to mid-20th century. By the 1950s, total hysterectomy supplanted supracervical techniques, largely as a method for preventing carcinoma of the cervix. Surgical alternatives to hysterectomy started in the 1930s with abdominal myomectomy and the first publication of nonhysteroscopic endometrial ablation from Germany, but by the end of the 20th century, included a plethora of techniques including laparoscopic, hysteroscopic, and interventional radiologic approaches. The advent of early detection of, and even prevention of, preinvasive cervical neoplasia, has led to a reevaluation of the need for total hysterectomy in many patients. In the early years of the millennium, targeted leiomyoma therapy was under development with a range of energy sources including cryogenic and radiofrequency probes, as well as focused ultrasound, targeted and controlled by magnetic resonance imaging.

Female↗

Endometrial ablation: where have we been? Where are we going?

Endometrial ablation (EA) is targeted destruction of the endothelial surface of the uterine cavity. The procedure was originally designed as a less invasive alternative to hysterectomy for the symptom of heavy menstrual bleeding unrelated to structural pathology of the uterus, that was not responsive to medical therapy. More recently it has become apparent that the procedure can be performed in the presence of submucous leiomyomas, providing they meet a number of size and location criteria. The first EA serie as published in Germany in the 1930s, but the procedure did not attract much attention until the latter part of the 20th century. Currently, EA can be performed under endoscopic direction with the neodymium:yttrium alumnum garnet laser, with a radiofrequency resectoscope, or with an expanding array of nonresectoscopic EA systems. It is apparent that most but not all of the complications associated with resectoscopic endometrial ablation are eliminated with nonresectoscopic endometrial ablation, but serious morbidity has been reported with all of the newer systems to date. Success and patient satisfaction seem to be enduring in the majority of well-selected patients treated in clinical trials, but repeat surgery, usually hysterectomy, is performed in 25% to 40% by 5 years after surgery. Increased efficiencies should be realized if the procedure could be moved to an office setting.

Catheter Ablation↗

Myolysis of uterine fibroids: is there a role?

Myolysis is among the new procedures under development for the treatment of symptoms related to uterine leiomyoma. The procedure targets the destruction of fibroids using one of a number of focused energy delivery systems including those based upon radiofrequency electricity, supercooled cryoprobes, and, most recently, focused ultrasound monitored by real time magnetic resonance imaging. For thermomyolysis and cryomyolysis, delivery of the energy requires access to the tissue by laparoscopy, and, in some instances, hysteroscopy. For focused ultrasound, the patient is detached from the energy source, which is delivered by an array of external beams. Clinical evaluation has been confined to case series, but it is evident that the approach results in a variable degree of reduction of the total uterine mass, and, usually, a reduction in uterine bleeding. Clearly, longer term appropriately designed comparative trials are required that evaluate and compare myolysis with myomectomy, uterine artery embolization, and hysterectomy, to name a few.

Cryosurgery↗

Abnormal uterine bleeding and underlying hemostatic disorders: report of a consensus process.

An ad hoc consensus group determined that the prevalence of von Willebrand's disease in females with heavy menstrual bleeding is approximately 13%, but the severity of the disorder varies and, consequently, the overall clinical impact remains unknown. Consensus recommendations are presented, which include [1] a structured history for screening females with heavy menstrual bleeding; [2] a collaborative, multidisciplinary evaluation, and [3] a strategy for future basic science and clinical investigation.

Blood Coagulation Disorders↗

Endometrial ablation for heavy menstrual bleeding.

PURPOSE OF REVIEW: This review evaluates the currently available evidence regarding resectoscopic endometrial ablation (REA) and the various nonresectoscopic endometrial ablation (NREA) techniques used for heavy menstrual bleeding. RECENT FINDINGS: Laser endometrial ablation is now used infrequently, largely because of procedure time, but also because of the cost and training associated with the technique. REA can be performed in a wider spectrum of endometrial cavity configurations than NREA and, at least in expert hands, remains the gold standard. Each of the five available types of NREA device possesses advantages and disadvantages over the others with respect to variables such as treatment time, required cervical dilation, and size and configuration of the endometrial cavity. All provide acceptable results that are comparable to that of REA in expert hands. Serious complications seem to be less common with NREA, but uterine perforation and bowel or other visceral injury can still occur. When endometrial-ablation patients were followed for up to 5 years, repeat surgery rates ranged from 20 to 40%, thereby eroding both the direct and indirect treatment-related resource utilization. Levonorgestrel-releasing intrauterine devices demonstrate similar clinical and patient-satisfaction outcomes to endometrial ablation but can be inserted in the office and allow maintenance of fertility. SUMMARY: Both REA and NREA provide at least short- to intermediate-term options to hysterectomy for patients with heavy menstrual bleeding and normal or near-normal endometrial cavities. Consequently, the ideal candidates are likely those who are within 5 years of menopause.

Electrocoagulation↗

Endometrial ablation with a thermal balloon: the first 10 years.

Thermal balloon endometrial ablation (BEA) was introduced approximately 10 years ago as the first automated replacement for hysteroscopic endometrial ablation (HEA) in women with chronic abnormal uterine bleeding. Putative advantages included similar or improved clinical outcomes, and reduction of both adverse outcomes and the total cost of care, all with reduced requirements for operator skill. The published literature contains 1191 cases of BEA performed with instruments from 4 manufacturers, including a number of randomized clinical trials (RCTs) comparing the devices with HEA, usually performed by experts. In comparative RCTs, clinical and health-related quality of life outcomes as well as patient satisfaction and rate of subsequent uterine surgery appear similar in follow-up intervals that ranged from 1 to 5 years. There is a suggestion of reduced risk of adverse events with BEA, but the differences are small. There are no rigorous evaluations of resource use. The level of surgeon expertise in HEA arms of available RCTs potentially improves quality and decreases complications over what might be expected in the general population. Thus BEA seems equivalent to HEA when performed by expert surgeons with respect to most outcomes. Effectiveness studies of the two interventions should be conducted in community settings and should evaluate resource use.

Catheter Ablation↗

Capacitive coupling: a comparison of measurements in four uterine resectoscopes.

STUDY OBJECTIVE: To compare electrosurgical waveform and electrode integrity as variables in the capacitive induction of current to the external sheath of four different resectoscopes. DESIGN: Laboratory comparative study. SETTING: Surgical laboratory. INSTRUMENTATION: Valleylab Force FX and Force 4 radiofrequency (RF) electrosurgical units (ESUs); resectoscopes from four manufacturers; and rollerball electrodes, both intact and with standardized insulation defects. The ESU was fired over a working range of high- and low-voltage outputs in open circuit conditions, and current and wattage were measured and recorded from both the electrodes and the external sheath. MEASUREMENTS AND MAIN RESULTS: With intact insulation, relatively little current was measurable on the external sheath of any of the resectoscopes regardless of the power or waveform. However, with high-voltage outputs, most proximal insulation defects, and some distal defects, a large proportion of ESU output was measured on the external sheath. There were no such findings with any resectoscope, at any power setting or with any insulation defect, with low-voltage ("cutting") outputs. CONCLUSIONS: These results confirm that high-voltage outputs may present a greater risk for current diversion to the external sheath of any of the monopolar resectoscopes tested and that this could contribute to the risk of lower genital tract injury during RF resectoscopic surgery.

Electric Capacitance↗

The impact of trocar-cannula design and simulated operative manipulation on incisional characteristics: a randomized trial.

OBJECTIVE: To evaluate the hypothesis that abdominal muscular and fascial defects associated with 12-mm blunt conical trocar-cannula system will be similar to those associated with 8-mm pyramidal trocar-cannula system, both with and without simulated operative movements. METHODS: A randomized trial was performed in an animal (white swine) model. Four trocar-cannula system groups were evaluated: group A, 12-mm blunt conical system, no operative manipulations; group B, 12-mm blunt conical system, standardized operative manipulation; group C, 8-mm pyramidal system, no operative manipulations; group D, 8-mm pyramidal system with standardized operative manipulation. These 4 groups were randomly assigned across 8 animals and 6 locations for a total of 48 insertions. After the cannulas were removed, the skin and subcutaneous tissues were dissected to expose the fascial wounds. Maximal incisional length, wound area, and muscle damage score were determined for each defect. RESULTS: Mean wound area was 8.58 mm(2) in group A, 9.71 mm(2) in group B, 9.83 mm(2) in group C, and 9.63 mm(2) in group D. Incisional length was 9.16 mm in group A, 9.61 mm in group B, 9.14 mm in group C, and 8.52 mm in group D. There were no statistically significant differences between any 2 groups. Mean muscle injury scores were also similar for all groups. CONCLUSIONS: Twelve-millimeter conical trocar-cannula systems create fascial defects similar to those of 8-mm pyramidal systems, both immediately after insertion and after simulated operative manipulations. Given the historical low risk of wound dehiscence and hernia associated with pyramidal devices less than 10-mm in outside diameter, fascial closure of wounds created by conical systems may be unnecessary.

Abdominal Injuries↗

Factors affecting capacitive current diversion with a uterine resectoscope: an in vitro study.

STUDY OBJECTIVE: To evaluate electrosurgical waveform, generator type, and electrode integrity as variables in capacitive induction of current on the external sheath of a resectoscope in open-circuit conditions. DESIGN: In vitro, laboratory, comparative study (Canadian Task Force classification CII-1). SETTING: Surgical laboratory. INSTRUMENTATION: Three ValleyLab radiofrequency (RF) electrosurgical generators (ESU), Force-2, Force-4, and Force-F/X; a resectoscope (Storz 50 series); and rollerball electrodes, both intact and with two types of standard insulation defects (lateral and circumferential) placed in two locations: distally, beyond the end of the telescope, and proximally, beside the distal aspect of the telescope. A Dynatek ESU analyzer was used to record current and wattage on electrodes and the external sheath. MEASUREMENTS AND MAIN RESULTS: With intact insulation, current was not disproportionately induced on the external sheath of the resectoscope regardless of ESU, power, or waveform. Proximally located electrode insulation defects allowed induction of most of the generator's output to the external sheath when high-voltage modulated outputs were used, and the risk varied somewhat with the ESU. There was no such induction at any power setting or with any insulation defect when low-voltage (cutting) outputs were tested. CONCLUSION: In the presence of proximal electrode defects, high-voltage currents may contribute to thermal injury to the lower genital tract during RF resectoscopic surgery.

Electric Capacitance↗

Randomized comparison of the effect of manipulation on incisional parameters associated with a pyramidal laparoscopic trocar-cannula system and the EndoTIP cannula.

We conducted a randomized, controlled trial to evaluate the effect of laparoscopic access cannula manipulation on fascial and incisional characteristics in a white swine model, comparing a pyramidal trocar-cannula system (PTC) and a trocarless threaded cannula (TTC, EndoTIP). We made 6 insertions in 10 animals. Cannulas randomized to the movement group were manipulated in standard fashion in skin and subcutaneous tissues. After dissection, muscle damage scores, wound areas, and maximum wound lengths were determined. Mean muscle damage scores without and with manipulation for the TTC were 0.7 and 1.00, respectively, and for the PTC 1.9 and 2.0. Differences between devices were significant (p = 0.0001) but there were no differences within devices (manipulation vs no manipulation). Mean wound length for the TTC without manipulation (0.699 cm) was less than that after manipulation (1.101 cm, p = 0.0002). The mean nonmanipulated PTC wound length (0.968 cm) was more than that of corresponding TTC wounds (0.699 cm, p = 0.0082) but this difference was lost after manipulation (TTC 1.101, PTC 0.930). Mean wound area for the nonmanipulated TTC was less than that for corresponding PTC wounds (16.99 vs 30.85 mm(2), p = 0.0066) but this difference was lost after manipulation (TTC 24.31 mm(2), PTC 25.97 mm(2)). Thus cannula manipulation had no effect on wound area and an adverse effect on maximum wound length for the threaded cannula only. Despite movement, the muscle damage score remained significantly less for the threaded cannula.

Abdominal Wall↗

Electrosurgery-induced generation of gases: comparison of in vitro rates of production using bipolar and monopolar electrodes.

STUDY OBJECTIVE: To compare rates of production of gases generated by VersaPoint bipolar hysteroscopic vaporizing electrodes using normal saline and monopolar vaporizing electrodes using 1.5% glycine. DESIGN: In vitro study (Canadian Task Force classification II-1). SETTING: Laboratory. MATERIAL: Bovine cardiac muscle. INTERVENTION: Fresh morbid bovine cardiac muscle was fully immersed in normal saline for the bipolar system and in 1.5% glycine for monopolar systems. Loop and bulk vaporizing electrodes were activated by radiofrequency electrosurgical units (ESUs) appropriate for each system, at standard powers and at settings higher than those in clinical use. MEASUREMENTS AND MAIN RESULTS: Rates of gas production were calculated and data analyzed by analysis of variance. For bulk vaporizing electrodes, the highest gas production rates at standard settings occurred with monopolar electrodes and the Force 2 generator at 300 W, and the Force FX at 200 W. At slightly higher than standard 200-W settings, the VersaPoint bipolar bulk vaporizing electrode was associated with lowest gas production rates in this category. Although there were statistically significant differences between loop electrodes, the magnitude remained small at similar ESU settings, and differences are thought to be clinically insignificant. CONCLUSION: Rates of gas production in this model appeared to vary most with ESU power output settings and relatively little with electrosurgical modality (bipolar or monopolar).

Animals↗

Consensus statement for the management of chronic pelvic pain and endometriosis: proceedings of an expert-panel consensus process.

OBJECTIVE: To develop recommendations for the medical and surgical care of women who present with chronic pelvic pain (CPP) and are likely to have endometriosis as the underlying cause. DESIGN: An expert panel comprised of practicing gynecologists from throughout the United States and experts in consensus guideline development was convened. After completion of a structured literature search and creation of draft algorithms by an executive committee, the expert panel of >50 practicing gynecologists met for a 2-day consensus conference during which the clinical recommendations and algorithms were reviewed, refined, and then ratified by unanimous or near-unanimous votes. PATIENT(S): Women presenting with CPP who are likely to have endometriosis as the underlying cause. MAIN OUTCOME MEASURE(S): None. CONCLUSION(S): Chronic pelvic pain frequently occurs secondary to nongynecologic conditions that must be considered in the evaluation of affected women. For women in whom endometriosis is the suspected cause of the pain, laparoscopic confirmation of the diagnosis is unnecessary, and a trial of medical therapy, including second-line therapies such as danazol, GnRH agonists, and progestins, is justified provided that there are no other indications for surgery such as the presence of a suspicious adnexal mass. When surgery is necessary, laparoscopic approaches seem to offer comparable clinical outcomes to those performed via laparotomy, but with reduced morbidity. The balance of evidence supports the use of adjuvant postoperative medical therapy after conservative surgery for CPP. There is some evidence that adjuvant presacral neurectomy adds benefit for midline pain, but currently, there is inadequate evidence to support the use of uterosacral nerve ablation or uterine suspension. Hysterectomy alone has undocumented value in the surgical management of women with endometriosis-associated CPP.

Algorithms↗

Peer review.

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Forecasting↗

Intraabdominal pressure and incision parameters associated with a pyramidal laparoscopic trocar-cannula system and the EndoTIP cannula.

STUDY OBJECTIVE: To compare intraabdominal pressure and incision characteristics associated with insertion of a disposable pyramidal trocar-cannula system (T-CS) and the EndoTIP threaded cannula, a trocarless, reusable laparoscopic access device. DESIGN: Randomized trial (Canadian Task Force classification I). SUBJECTS: White swine. INTERVENTION: . Six insertions were created on the lower abdomen of 10 animals; changes in intraabdominal pressure associated with insertion of the pyramidal T-CS and threaded cannula were recorded by a computerized system. Once insertions were completed, skin and subcutaneous tissues were dissected to expose fascial wounds. MEASUREMENTS AND MAIN RESULTS: Incision length and wound area and muscle damage scores were determined. The mean change in intraabdominal pressure for the pyramidal T-CS was 4.44 mm Hg and for the threaded cannula was 2.76 mm Hg (p = 0.0001). Mean incision length, mean wound area score, and mean muscle damage score for the pyramidal T-CS were 0.968 cm, 30.9 mm(2), and 1.9/4, respectively, and for the threaded cannula they were 0.699 cm (p = 0.0082), 17.0 mm(2) (p = 0.0066), and 0.7/4 (p = 0.001), respectively. CONCLUSION: In this model, insertion of the threaded cannula created less change in intraabdominal pressure and smaller fascial and muscle defects than insertion of the pyramidal T-CS.

Abdomen↗

Laparoscopic access: complications, technologies, and techniques.

PURPOSE OF REVIEW: To review laparoscopic access systems, insertion techniques, and the risks of complications associated with their use. RECENT FINDINGS: Access devices usually comprised an external cannula and a removable sharp pyramidal trocar for penetration of the abdominal wall, and were nearly universally positioned following establishment of a pneumoperitoneum. However, it is apparent that such devices and techniques contribute to patient morbidity through visceral and vascular injury, as well as incision-related complications such as dehiscence and hernia. There exist alternative approaches to positioning insufflation needles and the initial cannula, which may reduce the incidence of vascular and visceral injury particularly in the face of previous abdominal surgery. Inserting the initial cannula after minilaparotomy is associated with a reduced risk of vascular injury, but visceral complications still occur. Some new access instruments may reduce the risk of some complications associated with 'blind entry', and although not all seem to be effective in this regard, a set of blunt-tipped devices now exist, which are surprisingly easy to position and may limit the risk of injury while significantly reducing the size of the myofascial defect in the abdominal wall. Port site metastasis is a relatively newly recognized complication of oncological surgery and is a concern, but further investigation is required to determine whether such metastasis is related to a change in clinical outcome. SUMMARY: The incidence and spectrum of access-related complications is greater than previously perceived. Newer devices and modifications in technique may reduce the incidence of such adverse events.

Blood Vessels↗

Endometrial hydrothermablation: a comparison of short-term clinical effectiveness in patients with normal endometrial cavities and those with intracavitary pathology.

STUDY OBJECTIVE: To evaluate preprocedure and postprocedure health related quality of life scores and patient satisfaction of women treated with hydrothermablation for abnormal uterine bleeding (AUB) with and without endometrial intracavitary pathology. DESIGN: Cohort study (Canadian Task Force classification II-2). SETTING: Two institutions from a large managed care organization. PATIENTS: Forty-seven English-speaking premenopausal women with AUB, both with and without leiomyomas or polyps in the endometrial cavity treated from January 2001 through March 2003. INTERVENTION: Patients had been treated with endometrial hydrothermablation. MEASUREMENTS AND MAIN RESULTS: A standardized system, validated in English (the Ruta score), was used for evaluating health-related quality-of-life impact of uterine bleeding. Following the index procedure, patients were asked to assess both baseline and current status. A simple five-point satisfaction scale also was administered. Outcomes from subjects with and without documented endometrial structural pathology were compared. Follow-up ranged from 5 to 25 months with a mean of 12.7 (SD 5.2). Twenty women in the cohort had normal endometrial cavities, and 27 demonstrated intracavitary pathology, most often leiomyomas. For both groups, baseline and follow-up scores were similar. Satisfaction scores also were similar with 80.0% of the subjects with normal endometrial cavities and 72.7% of those with abnormal cavities satisfied or highly satisfied with the outcome. CONCLUSION: Endometrial hydrothermablation seemed to be effective for AUB-affected women, both with and without pathologic lesions in the endometrial cavity.

Adult↗