Review Received: April 14, 2014 Accepted after revision: February 3, 2015 Published online: March 20, 2015
Gynecol Obstet Invest 2015;80:3–9 DOI: 10.1159/000377700
Outpatient Hysteroscopic Polypectomy: Bipolar Energy System (Versapoint®) versus Mechanical Energy System (TRUCLEAR System®) – Preliminary Results Jennifer Rovira Pampalona a Maria Degollada Bastos a Gemma Mancebo Moreno b Esther Ratia Garcia a Andrea Buron Pust c Joan Carles Mateu Pruñonosa a Angel Guerra Garcia a Ramon Carreras Collado b Pere Bresco Torras a
a
Department of Obstetrics and Gynecology, Hospital d’Igualada – Consorci Sanitari de l’Anoia, Igualada, and Departments of b Obstetrics and Gynecology and c Epidemiology and Evaluation, Hospital del Mar, Barcelona, Spain
Key Words Diagnostic hysteroscopy · Operative hysteroscopy · TRUCLEAR System® · Versapoint® · Bipolar energy · Mechanical energy
Abstract Hypothesis: The new hysteroscopic system with mechanical energy is an effective outpatient technique for diagnosis and treatment that has certain advantages over conventional hysteroscopy in the management of endometrial polyps. Objectives: Our primary objective was to assess the total duration of hysteroscopy and polypectomy performed in an outpatient setting comparing the new mechanical energy hysteroscopy to the bipolar energy system. Our secondary objective was to compare the level of safety of both hysteroscopic techniques using the procedure success rate, the need for subsequent referral to surgery, existing complications, and comfort experienced by the patient during the procedure. Patients and Methods: This randomized controlled trial included the first 90 patients with an ultrasound diagnosis of endometrial polyp (>1 cm) who underwent an outpatient diagnostic and operative hysteroscopy at the Igualada Hospital (Barcelona) and agreed to be included in
© 2015 S. Karger AG, Basel 0378–7346/15/0801–0003$39.50/0 E-Mail [email protected] www.karger.com/goi
the study by signing an informed consent. Results: We obtained a 91% success rate with the TRUCLEAR System® compared to a 69% success rate with the Versapoint® system. Total operating time was 6.36 min in the TRUCLEAR System group versus 10.82 min in the Versapoint system group (p < 0.05), with a polypectomy time of 3.06 and 7.91 min, respectively (p < 0.05). There were no significant differences between the two techniques when analyzing pain using the visual analogue scale. No complications were recorded for either technique. Conclusion: The mechanical energy system presents a significant decrease in the total duration of polypectomy and hysteroscopy when performed both by experienced staff and by staff in training, resulting in higher success rates without complications with respect to conventional hysteroscopy with bipolar energy. © 2015 S. Karger AG, Basel
Introduction
It is known that there is a prevalence of endometrial polyps in 24–25% of the general population, with greater incidence in patients who are between 40 and 65 years old [1]. Most are asymptomatic and are diagnosed incidenJennifer Rovira Pampalona Carretera de Tàrreganúm 23 ES–25310 Agramunt (Spain) E-Mail Jrovira @ csa.cat
Downloaded by: Kungliga Tekniska Hogskolan 198.143.54.65 - 8/8/2015 5:27:36 PM
Patients and Methods Study Design In this randomized controlled trial, a total of 90 women studied between March and September 2013 at the Consorci Sanitari de l’Anoia – Hospital d’Igualada were included. Inclusion criteria were an ultrasound diagnosis of endometrial polyp >1 cm and the agreement to be included in the study after having read and signed the informed consent form. All patients who agreed to be included in the study needed to have the signed consent form with them on the day of the procedure. This consent form had been given to them beforehand at the doctor’s office, at which time the procedure and the study in which they would be included were discussed with them. Patients were also given an information sheet on the procedure and the purpose of the study. This clinical trial was approved by the Clinical Research Ethics Committee of the University Hospital of Bellvitge (reference AC147/12) and presented as sponsor’s protocol code No. JEN-HTS-2013-19. The hysteroscopic systems used, which were randomized for each patient, were the TS with mechanical energy and the VS with bipolar radiofrequency energy. The TS hysteroscope has a 0° optical lens and a total diameter of 5.6 mm when inserting the external
4
Gynecol Obstet Invest 2015;80:3–9 DOI: 10.1159/000377700
sheath. It is used in conjunction with an intrauterine tissue removal device with a cutting window at the distal end that, combined with the rotating movement, makes it possible to resect the entire intracavitary lesion. All procedures performed with the VS bipolar energy system were conducted with an Olympus® 3-mm rigid hysteroscope consisting of a 30° optical lens and having a total diameter of 5.5 mm when inserting the external sheath. The electrosurgery instruments used were the VS bipolar energy system consisting of small-caliber electrodes inserted through the working channel (5 Fr). In our study, we worked with the Twizzle tip electrode at a voltage of 50 W and cut output VC3. Saline was used as a uterine distention medium with both systems. Patients were randomized using a computer-generated random sequence created with the Excel program. This sequence resulted in 4 groups as possible combinations for patients included in the study, where group 1 was staff experienced in the TS technique, group 2 was staff experienced in the VS technique, group 3 was staff undergoing training in the TS technique, and group 4 was staff undergoing training in the VS technique. The sequence was not known by the surgeon performing the procedure. The nurse in charge of the unit informed the patients prior to the intervention about the relevant randomization (1, 2, 3, or 4) and, henceforth, about the physician in charge and the technique to be used during the hysteroscopic procedure. An experienced/senior physician was a physician with over 10 years’ experience with the VS and more than 2 years’ experience with the TS, and a junior physician was a 4th-year resident in gynecology and obstetrics undergoing training in hysteroscopic techniques. Surgical Technique The patients, as per our hospital protocol, did not use antibiotic prophylaxis or receive prior administration of anti-inflammatory drugs or sedatives, except those who routinely took such medication. No paracervical anesthetic of any kind was given to any patient. Before the procedure, all patients underwent a transvaginal ultrasound to measure the polyp size using the longitudinal and anteroposterior diameter. The procedure was performed without prior endometrial preparation of the patient and with saline used for uterine distention. A systematic examination of the uterine cavity was conducted after inserting the hysteroscope into the cavity with the vaginoscopic technique. After confirming the presence of the lesion, a polypectomy was performed using either the mechanical tissue removal device or the bipolar electrode, depending on the random assignment of the patient. We recorded the total operating time from the insertion of the hysteroscope into the vagina until the hysteroscope was removed upon completion of the procedure. Duration of the polypectomy was defined as the time required for complete resection and removal of the endometrial polyp. Polyps were excised serially to the base. The procedure was not considered successful in the case of direct amputation with the presence of tissue at the level of the endometrial lining or incomplete removal of the material from the uterine cavity. We considered 30 min to be the maximum amount of time for the procedure, since it is the accepted time limit at our hospital for conducting diagnostic and operative hysteroscopy. Patients whose cavity could not be entered and those with nonviable polyps or partial polypectomies were referred for subsequent hysteroscopic surgery in the surgery unit.
Rovira Pampalona et al.
Downloaded by: Kungliga Tekniska Hogskolan 198.143.54.65 - 8/8/2015 5:27:36 PM
tally while performing an ultrasound; however, when they are symptomatic they present in the form of abnormal uterine bleeding [2]. Endometrial polyps are generally benign, but there is a known risk of malignancy that can be highly variable depending on the series of patients. Patients with risk factors such as menopause, symptoms of dysfunctional uterine bleeding, a history of endometrial hyperplasia, and large polyps, among others [2, 3], can account for up to 10% of patients [4]. Systematic resection of endometrial polyps with subsequent histological study allows for the detection of malignant polyps even in asymptomatic and/or premenopausal patients [4, 5]. The introduction of mechanical energy, initially with hysteroscopic surgery [6–8] and subsequently with diagnostic hysteroscopy, has led to a reduction in the rate of complications mainly caused by the presence of electrodes in the operative field, as occurs with monopolar and bipolar radiofrequency energy [9]. To confirm our hypothesis that the new mechanical energy system has certain advantages over conventional hysteroscopy with bipolar energy, we designed a comparative study to perform an outpatient diagnostic and operative hysteroscopy with the new TRUCLEAR System® (TS; Smith & Nephew, Andover, Mass., USA) with mechanical energy and compared it to the Versapoint® system (VS; Gynecare; Ethicon, Somerville, N.J., USA) with bipolar energy, subsequently assessing total procedure time in the 90 patients included in the study who had an ultrasound diagnosis of endometrial polyp >1 cm.
Study Variables The following variables were collected for the study: physician performing the procedure, patient demographic data, personal medical history (relevant pathological history and current treatment), obstetric history (parity, mode of delivery, menopause), current condition (reason for performing hysteroscopy, symptoms, and previous ultrasound), procedure (diagnostic hysteroscopy, procedure performed, operating time, success of the technique, and intraoperative complications), subsequent referral to the ambulatory surgery unit for hysteroscopic surgery, pain reported by the patient assessed using the VAS, and results of the histological study.
Table 1. Clinical characteristics
VS (n = 33)
TS (n = 48)
Mean age, years 58.9 (54.11 – 63.82) 49.4 (45.69 – 53.17) Menopause, % 69.7 (0.51 – 0.83) 44 (0.25 – 0.56) Parity 5 (0.05 – 0.25) Nulliparous 9 (0.12 – 0.42) Primiparous 4 (0.04 – 0.29) 13 (0.16 – 0.41) ≥2 children 20 (0.12 – 0.57) 30 (0.05 – 0.62) Mode of delivery 33 (0.43 – 0.71) Vaginal 19 (0.39 – 0.73) Cesarean 2 (0.01 – 0.22) 3 (0.01 – 0.18) 7 (0.05 – 0.25) Vaginal + cesarean 3 (0.02 – 0.25) Values in parentheses are 95% confidence intervals.
Table 1 shows the clinical variables of the 81 patients included in the study. Seven patients were excluded at the time of the hysteroscopy as they did not have an endometrial polyp, and 2 patients were excluded from the study after obtaining the pathological study due to the histological diagnosis of leiomyoma. To conduct polypectomy, VS was used on 33 patients and TS was used on 48 patients. Of all hysteroscopies, 70% were performed by an experienced physician and 30% by a physician in training (fig. 1). The mean age was 52 years in the VS group compared to 54 years in the TS group. Most of the women were
menopausal (69.7 and 44%, respectively), of whom most had a parity >1 child, and the primary mode of delivery had been vaginal. The primary reason for the visit was abnormal uterine bleeding in 74% of patients, with dysfunctional uterine bleeding in 28 of the 36 premenopausal patients and postmenopausal metrorrhagia in 32 of the 45 postmenopausal patients. Endometrial polyp diagnosed while performing a transvaginal ultrasound during a routine visit was the other reason, amounting to 26% of cases. The pathologic study of the extracted samples showed endometrial polyp in 95% of cases. There were 2 cases of polyps with simple nonatypical hyperplasia (2.4%) and 2 cases of endometrial carcinoma (2.4%) located in the resected polyp, both of which were in symptomatic patients, a menopausal patient, and a premenopausal patient. We obtained a 91% success rate (n = 44) with the TS compared to a 69% success rate (n = 23) with the VS system. Of the total unsuccessful cases (n = 14), 4 (28%) were attributed to the TS system, where the only observed reason was the inability to enter the cavity. There were a total of 10 (71%) unsuccessful cases in the VS group, where the primary reason was the inability to remove the polyp, nonviable polyps because of their size, or partial removal in 9 out of 10 patients (90%). There was 1 case in which it was impossible to enter the cavity. Table 2 shows the number of unsuccessful cases for both systems. A total of 8% of patients in the TS group and 18% in the VS group were referred for a second operative hysteroscopy. Total operating time for the 67 cases in which the technique was considered successful was 6.36 min in the TS group and 10.82 min in the VS group, which is a statistically significant difference (p < 0.05). This mainly
Outpatient Hysteroscopic Polypectomy: Bipolar versus Mechanical Energy System
Gynecol Obstet Invest 2015;80:3–9 DOI: 10.1159/000377700
Statistical Analysis Data analysis was performed using the statistical analysis package SPSS version 13.0. The sample size was calculated in relation to the main objectives, i.e., to ensure sufficient statistical power in the overall comparison of the TS and the VS system and in the subgroup of residents and adjuncts. Accepting an alpha risk of 0.05 and a lower beta risk of 0.2 in a two-tailed test and to detect a difference ≥300 s, assuming a standard deviation of 500, it is necessary to have 49 cases in each group to be compared. We estimated a loss rate of 10%, which is included in the calculation of the sample size. Losses were considered those cases in which resection and/or removal of the polyp was incomplete or cases in which the uterine cavity could not be entered, considering such cases as procedure failures. We have also presented the 95% confidence intervals for the main quantitative variables of the results associated with the primary objective and for the main secondary variables. We considered a p value
Gynecol Obstet Invest 2015;80:3–9 DOI: 10.1159/000377700
Outpatient Hysteroscopic Polypectomy: Bipolar Energy System (Versapoint®) versus Mechanical Energy System (TRUCLEAR System®) – Preliminary Results Jennifer Rovira Pampalona a Maria Degollada Bastos a Gemma Mancebo Moreno b Esther Ratia Garcia a Andrea Buron Pust c Joan Carles Mateu Pruñonosa a Angel Guerra Garcia a Ramon Carreras Collado b Pere Bresco Torras a
a
Department of Obstetrics and Gynecology, Hospital d’Igualada – Consorci Sanitari de l’Anoia, Igualada, and Departments of b Obstetrics and Gynecology and c Epidemiology and Evaluation, Hospital del Mar, Barcelona, Spain
Key Words Diagnostic hysteroscopy · Operative hysteroscopy · TRUCLEAR System® · Versapoint® · Bipolar energy · Mechanical energy
Abstract Hypothesis: The new hysteroscopic system with mechanical energy is an effective outpatient technique for diagnosis and treatment that has certain advantages over conventional hysteroscopy in the management of endometrial polyps. Objectives: Our primary objective was to assess the total duration of hysteroscopy and polypectomy performed in an outpatient setting comparing the new mechanical energy hysteroscopy to the bipolar energy system. Our secondary objective was to compare the level of safety of both hysteroscopic techniques using the procedure success rate, the need for subsequent referral to surgery, existing complications, and comfort experienced by the patient during the procedure. Patients and Methods: This randomized controlled trial included the first 90 patients with an ultrasound diagnosis of endometrial polyp (>1 cm) who underwent an outpatient diagnostic and operative hysteroscopy at the Igualada Hospital (Barcelona) and agreed to be included in
© 2015 S. Karger AG, Basel 0378–7346/15/0801–0003$39.50/0 E-Mail [email protected] www.karger.com/goi
the study by signing an informed consent. Results: We obtained a 91% success rate with the TRUCLEAR System® compared to a 69% success rate with the Versapoint® system. Total operating time was 6.36 min in the TRUCLEAR System group versus 10.82 min in the Versapoint system group (p < 0.05), with a polypectomy time of 3.06 and 7.91 min, respectively (p < 0.05). There were no significant differences between the two techniques when analyzing pain using the visual analogue scale. No complications were recorded for either technique. Conclusion: The mechanical energy system presents a significant decrease in the total duration of polypectomy and hysteroscopy when performed both by experienced staff and by staff in training, resulting in higher success rates without complications with respect to conventional hysteroscopy with bipolar energy. © 2015 S. Karger AG, Basel
Introduction
It is known that there is a prevalence of endometrial polyps in 24–25% of the general population, with greater incidence in patients who are between 40 and 65 years old [1]. Most are asymptomatic and are diagnosed incidenJennifer Rovira Pampalona Carretera de Tàrreganúm 23 ES–25310 Agramunt (Spain) E-Mail Jrovira @ csa.cat
Downloaded by: Kungliga Tekniska Hogskolan 198.143.54.65 - 8/8/2015 5:27:36 PM
Patients and Methods Study Design In this randomized controlled trial, a total of 90 women studied between March and September 2013 at the Consorci Sanitari de l’Anoia – Hospital d’Igualada were included. Inclusion criteria were an ultrasound diagnosis of endometrial polyp >1 cm and the agreement to be included in the study after having read and signed the informed consent form. All patients who agreed to be included in the study needed to have the signed consent form with them on the day of the procedure. This consent form had been given to them beforehand at the doctor’s office, at which time the procedure and the study in which they would be included were discussed with them. Patients were also given an information sheet on the procedure and the purpose of the study. This clinical trial was approved by the Clinical Research Ethics Committee of the University Hospital of Bellvitge (reference AC147/12) and presented as sponsor’s protocol code No. JEN-HTS-2013-19. The hysteroscopic systems used, which were randomized for each patient, were the TS with mechanical energy and the VS with bipolar radiofrequency energy. The TS hysteroscope has a 0° optical lens and a total diameter of 5.6 mm when inserting the external
4
Gynecol Obstet Invest 2015;80:3–9 DOI: 10.1159/000377700
sheath. It is used in conjunction with an intrauterine tissue removal device with a cutting window at the distal end that, combined with the rotating movement, makes it possible to resect the entire intracavitary lesion. All procedures performed with the VS bipolar energy system were conducted with an Olympus® 3-mm rigid hysteroscope consisting of a 30° optical lens and having a total diameter of 5.5 mm when inserting the external sheath. The electrosurgery instruments used were the VS bipolar energy system consisting of small-caliber electrodes inserted through the working channel (5 Fr). In our study, we worked with the Twizzle tip electrode at a voltage of 50 W and cut output VC3. Saline was used as a uterine distention medium with both systems. Patients were randomized using a computer-generated random sequence created with the Excel program. This sequence resulted in 4 groups as possible combinations for patients included in the study, where group 1 was staff experienced in the TS technique, group 2 was staff experienced in the VS technique, group 3 was staff undergoing training in the TS technique, and group 4 was staff undergoing training in the VS technique. The sequence was not known by the surgeon performing the procedure. The nurse in charge of the unit informed the patients prior to the intervention about the relevant randomization (1, 2, 3, or 4) and, henceforth, about the physician in charge and the technique to be used during the hysteroscopic procedure. An experienced/senior physician was a physician with over 10 years’ experience with the VS and more than 2 years’ experience with the TS, and a junior physician was a 4th-year resident in gynecology and obstetrics undergoing training in hysteroscopic techniques. Surgical Technique The patients, as per our hospital protocol, did not use antibiotic prophylaxis or receive prior administration of anti-inflammatory drugs or sedatives, except those who routinely took such medication. No paracervical anesthetic of any kind was given to any patient. Before the procedure, all patients underwent a transvaginal ultrasound to measure the polyp size using the longitudinal and anteroposterior diameter. The procedure was performed without prior endometrial preparation of the patient and with saline used for uterine distention. A systematic examination of the uterine cavity was conducted after inserting the hysteroscope into the cavity with the vaginoscopic technique. After confirming the presence of the lesion, a polypectomy was performed using either the mechanical tissue removal device or the bipolar electrode, depending on the random assignment of the patient. We recorded the total operating time from the insertion of the hysteroscope into the vagina until the hysteroscope was removed upon completion of the procedure. Duration of the polypectomy was defined as the time required for complete resection and removal of the endometrial polyp. Polyps were excised serially to the base. The procedure was not considered successful in the case of direct amputation with the presence of tissue at the level of the endometrial lining or incomplete removal of the material from the uterine cavity. We considered 30 min to be the maximum amount of time for the procedure, since it is the accepted time limit at our hospital for conducting diagnostic and operative hysteroscopy. Patients whose cavity could not be entered and those with nonviable polyps or partial polypectomies were referred for subsequent hysteroscopic surgery in the surgery unit.
Rovira Pampalona et al.
Downloaded by: Kungliga Tekniska Hogskolan 198.143.54.65 - 8/8/2015 5:27:36 PM
tally while performing an ultrasound; however, when they are symptomatic they present in the form of abnormal uterine bleeding [2]. Endometrial polyps are generally benign, but there is a known risk of malignancy that can be highly variable depending on the series of patients. Patients with risk factors such as menopause, symptoms of dysfunctional uterine bleeding, a history of endometrial hyperplasia, and large polyps, among others [2, 3], can account for up to 10% of patients [4]. Systematic resection of endometrial polyps with subsequent histological study allows for the detection of malignant polyps even in asymptomatic and/or premenopausal patients [4, 5]. The introduction of mechanical energy, initially with hysteroscopic surgery [6–8] and subsequently with diagnostic hysteroscopy, has led to a reduction in the rate of complications mainly caused by the presence of electrodes in the operative field, as occurs with monopolar and bipolar radiofrequency energy [9]. To confirm our hypothesis that the new mechanical energy system has certain advantages over conventional hysteroscopy with bipolar energy, we designed a comparative study to perform an outpatient diagnostic and operative hysteroscopy with the new TRUCLEAR System® (TS; Smith & Nephew, Andover, Mass., USA) with mechanical energy and compared it to the Versapoint® system (VS; Gynecare; Ethicon, Somerville, N.J., USA) with bipolar energy, subsequently assessing total procedure time in the 90 patients included in the study who had an ultrasound diagnosis of endometrial polyp >1 cm.
Study Variables The following variables were collected for the study: physician performing the procedure, patient demographic data, personal medical history (relevant pathological history and current treatment), obstetric history (parity, mode of delivery, menopause), current condition (reason for performing hysteroscopy, symptoms, and previous ultrasound), procedure (diagnostic hysteroscopy, procedure performed, operating time, success of the technique, and intraoperative complications), subsequent referral to the ambulatory surgery unit for hysteroscopic surgery, pain reported by the patient assessed using the VAS, and results of the histological study.
Table 1. Clinical characteristics
VS (n = 33)
TS (n = 48)
Mean age, years 58.9 (54.11 – 63.82) 49.4 (45.69 – 53.17) Menopause, % 69.7 (0.51 – 0.83) 44 (0.25 – 0.56) Parity 5 (0.05 – 0.25) Nulliparous 9 (0.12 – 0.42) Primiparous 4 (0.04 – 0.29) 13 (0.16 – 0.41) ≥2 children 20 (0.12 – 0.57) 30 (0.05 – 0.62) Mode of delivery 33 (0.43 – 0.71) Vaginal 19 (0.39 – 0.73) Cesarean 2 (0.01 – 0.22) 3 (0.01 – 0.18) 7 (0.05 – 0.25) Vaginal + cesarean 3 (0.02 – 0.25) Values in parentheses are 95% confidence intervals.
Table 1 shows the clinical variables of the 81 patients included in the study. Seven patients were excluded at the time of the hysteroscopy as they did not have an endometrial polyp, and 2 patients were excluded from the study after obtaining the pathological study due to the histological diagnosis of leiomyoma. To conduct polypectomy, VS was used on 33 patients and TS was used on 48 patients. Of all hysteroscopies, 70% were performed by an experienced physician and 30% by a physician in training (fig. 1). The mean age was 52 years in the VS group compared to 54 years in the TS group. Most of the women were
menopausal (69.7 and 44%, respectively), of whom most had a parity >1 child, and the primary mode of delivery had been vaginal. The primary reason for the visit was abnormal uterine bleeding in 74% of patients, with dysfunctional uterine bleeding in 28 of the 36 premenopausal patients and postmenopausal metrorrhagia in 32 of the 45 postmenopausal patients. Endometrial polyp diagnosed while performing a transvaginal ultrasound during a routine visit was the other reason, amounting to 26% of cases. The pathologic study of the extracted samples showed endometrial polyp in 95% of cases. There were 2 cases of polyps with simple nonatypical hyperplasia (2.4%) and 2 cases of endometrial carcinoma (2.4%) located in the resected polyp, both of which were in symptomatic patients, a menopausal patient, and a premenopausal patient. We obtained a 91% success rate (n = 44) with the TS compared to a 69% success rate (n = 23) with the VS system. Of the total unsuccessful cases (n = 14), 4 (28%) were attributed to the TS system, where the only observed reason was the inability to enter the cavity. There were a total of 10 (71%) unsuccessful cases in the VS group, where the primary reason was the inability to remove the polyp, nonviable polyps because of their size, or partial removal in 9 out of 10 patients (90%). There was 1 case in which it was impossible to enter the cavity. Table 2 shows the number of unsuccessful cases for both systems. A total of 8% of patients in the TS group and 18% in the VS group were referred for a second operative hysteroscopy. Total operating time for the 67 cases in which the technique was considered successful was 6.36 min in the TS group and 10.82 min in the VS group, which is a statistically significant difference (p < 0.05). This mainly
Outpatient Hysteroscopic Polypectomy: Bipolar versus Mechanical Energy System
Gynecol Obstet Invest 2015;80:3–9 DOI: 10.1159/000377700
Statistical Analysis Data analysis was performed using the statistical analysis package SPSS version 13.0. The sample size was calculated in relation to the main objectives, i.e., to ensure sufficient statistical power in the overall comparison of the TS and the VS system and in the subgroup of residents and adjuncts. Accepting an alpha risk of 0.05 and a lower beta risk of 0.2 in a two-tailed test and to detect a difference ≥300 s, assuming a standard deviation of 500, it is necessary to have 49 cases in each group to be compared. We estimated a loss rate of 10%, which is included in the calculation of the sample size. Losses were considered those cases in which resection and/or removal of the polyp was incomplete or cases in which the uterine cavity could not be entered, considering such cases as procedure failures. We have also presented the 95% confidence intervals for the main quantitative variables of the results associated with the primary objective and for the main secondary variables. We considered a p value
