Laparoscopic Supracervical Hysterectomy Using EnSeal vs Standard Bipolar Coagulation Technique: Randomized Controlled Trial

Original Article

Laparoscopic Supracervical Hysterectomy Using EnSeal vs Standard Bipolar Coagulation Technique: Randomized Controlled Trial Ralf Rothmund, MD1, Bernhard Kraemer, MD1, Sara Brucker, MD, Florin-Andrei Taran, MD*, Markus Wallwiener, MD, Andrea Zubke, Diethelm Wallwiener, MD, and Wolfgang Zubke, MD From the Departments of Obstetrics and Gynecology, University of Tuebingen, Tuebingen (Drs. Rothmund, Kraemer, Brucker, Taran, A. Zubke, D. Wallwiener, and W. Zubke), and University of Heidelberg, Heidelberg (Dr. M. Wallwiener), Germany.

ABSTRACT Objective: To compare the EnSeal device with standard bipolar coagulation forceps in laparoscopic supracervical hysterectomy (LASH). Design: Prospective, randomized, controlled trial (Canadian Task Force classification I). Setting: University hospital. Patients: One hundred sixty patients who underwent LASH. Intervention: Eighty patients underwent LASH using the EnSeal device (experimental group), and 80 patients underwent LASH using standard bipolar coagulation forceps (control group) (www.clinicaltrials.gov; study identifier NCT01806012). Measurements and Main Results: Mean (SD) total operative time was 78.18 (33.96) minutes in the experimental group and 86.30 (35.34) minutes in the control group (p 5 .03). Documented blood loss was ,50 mL in 72 patients in the experimental group and 62 patients in the control group (p 5 .03), and was 50 to 100 mL in 8 patients in the experimental group and 18 patients in the control group (p , .001). Postoperative hospital stay was significantly shorter for patients in the experimental group compared with the control group: 2.01 (0.44) days vs 2.17 (0.47) days, respectively (p 5 .03). There was no difference in postoperative pain scores and complications between the two treatment groups. Conclusion: Total resection time was shorter in the experimental group, and the other investigated clinical parameters were not inferior in the experimental group compared with the control group. The results of the present study indicate that use of the EnSeal device is at least as reliable as the conventional electrocoagulation technique in LASH. Journal of Minimally Invasive Gynecology (2013) 20, 661–666 Ó 2013 AAGL. All rights reserved. Keywords:

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Bipolar electrocoagulation; Disposable device; EnSeal; Supracervical hysterectomy; Vessel sealing

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Supported by Ethicon Endo-Surgery (Europe) GmbH, Norderstedt, Germany. The authors have no commercial, proprietary, or financial interest in the products or companies described in this article. 1 Drs. Rothmund and Kraemer contributed equally to this work. Corresponding author: F.A. Taran, MD, Department of Obstetrics and Gynecology, University of Tuebingen, Calwerstr 7, 72076 Tuebingen, Germany. E-mail: [email protected] Submitted March 13, 2013. Accepted for publication April 24, 2013. Available at www.sciencedirect.com and www.jmig.org 1553-4650/$ - see front matter Ó 2013 AAGL. All rights reserved. http://dx.doi.org/10.1016/j.jmig.2013.04.014

A major advantage of laparoscopic supracervical hysterectomy (LASH) is seen in the minimally invasive approach leading to less blood loss, shorter hospital stay, and faster convalescence [1,2]. Recently, the electrosurgical resources for tissue preparation and vessel sealing have been expanded to include devices that can offer both coagulation and cutting. These instruments need not be exchanged during the procedure; however, it is essential that they withstand high intraluminal pressure and have optimal coagulation properties [3–5]. However, not only the technical aspects are of interest but also the economic

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considerations inasmuch as modern instruments have potential cost-saving properties as a result of reduction in total operative time, use of postoperative pain medication, and hospital stay. Safety and performance of the EnSeal device for tissue sealing and cutting has already been demonstrated in experimental and clinical settings [6–9]. The EnSeal device uses nanometer-sized particles embedded in a bipolar temperature coefficient matrix. The cutting mechanism uses high and equal tissue compression to enhance the seal as the blade is advanced along the length of the jaw. Current flow is active only when the device jaws are closed, and is modulated at the tissueelectrode interface by nanoparticles that locally interrupt current flow to tissue when temperatures exceed 100 C. This enables sealing and transection to occur in a single step, as well as simultaneous current regulation minimizing collateral thermal spread and tissue damage [10]. In a comparison of maximum temperature and thermal spread during vessel sealing between the EnSeal device and other third-generation vessel sealing devices in a porcine model, it was reported that the EnSeal device produced mean lower peak temperatures and decreased mean thermal spread to surrounding tissues [10]. The objective of this prospective, controlled, randomized clinical trial was to compare the resection time as well as additional clinical parameters and postoperative complication rates for LASH performed using the EnSeal device compared with LASH performed using standard bipolar coagulation forceps. Materials and Methods Patients A total of 160 patients underwent LASH (Table 1). Indications for surgery were benign gynecologic conditions; all patients underwent LASH to treat bleeding disorders and/or uterine leiomyomas. After giving informed consent, patients underwent surgery using the EnSeal device (experimental group) or standard bipolar coagulation (control group) according to computer-generated permuted-block randomization. Patients undergoing concomitant procedures such as oophorectomy or major adhesiolysis (.5 coagulation and cutting steps) were excluded. The study was approved by the Ethics Committee of the University of Tuebingen (No.59/2010MPG23) (www.clinicaltrials.gov; study identifier NCT01806012). Instruments and Settings The EnSeal device (Fig. 1) is designed for laparoscopic vessel sealing and tissue transection. The device has a static lower jaw with an integrated first electrode, and a movable upper jaw containing the second electrode. Impedance of the nano-based material of the upper electrode depends on the temperature (positive temperature coefficient) and thereby regulates the energy output depending on the tissue

Table 1 Patient baseline demographic and clinical characteristicsa

Variable Age (yrs) Height (cm) Weight (kg) Parity Nulliparous Primiparous Multiparous Previous cesarean section History of relevant gynecologic operations other than cesarean section a

Experimental Control group group (n 5 80) (n 5 80) p value 46.08 (5.57) 164.75 (6.85) 69.70 (13.75)

45.85 (4.77) 165.75 (6.58) 72.0 (17.15)

.96 .30 .56

11 15 54 15

12 11 57 31

.82 .39 .61 .19

24

31

.24

Values are given as mean (SD) or number of patients.

temperature, not allowing the temperature to exceed 100 C. The double T-shaped cutting blade located longitudinally in the instrument axis closes the jaws while moving the blade to the front position. The coagulation and cutting processes occur almost simultaneously, and the clamp force depends on the blade position in which the two jaws are substantially parallel in closed position. The following devices and settings were used in the present study: NSEAL535RE (Ethicon Endo-Surgery GmbH, Norderstedt, Germany), with an Erbe VIO 300 D generator (Erbe-Elektromedizin GmbH, Tuebingen, Germany). The EnSeal handpiece is attached to the generator via a specific adapter to obtain the preadjustment of the device for optimal sealing and cutting. The standard bipolar coagulation forceps used was the bipolar RoBi clamp (Karl Storz GmbH & Co. KG, Tuttlingen, Germany), with the following settings: Erbe VIO 300 D generator (Erbe-Elektromedizin); setting: bipolar soft, effect 4, 60 W.

Fig. 1 EnSeal device.

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Table 2 Total and T1–T3 operative times 95% CI Operative time (min)

Experimental groupa

Control groupa

p valueb

Mean difference

Minimum

Maximum

T1 T2 T3 Total operative time

15.10 (5.51) 24.90 (14.80) 38.00 (22.25) 78.18 (33.96)

16.21 (5.53) 36.23 (25.44) 33.86 (14.12) 86.31 (35.34)

.19 ,.001 .42 .03

21.11 211.33 4.14 28.13

22.84 217.84 21.69 218.95

0.61 24.83 9.97 2.70

CI 5 confidence interval. a Values are given as mean (SD). b Mann-Whitney U test. There was a linear correlation between total operative time and uterus weight, r 5 0.68 (Pearson correlation coefficient); T1, r 5 0.31; T2, r 5 0.50; and T3, r 5 0.60.

Premedication and Anesthesia Premedication and anesthesia were administered according to established procedures of the Department of Anesthesia, University of Tuebingen (Tuebingen, Germany). Surgical Interventions and Settings LASH was performed as previously described, using either the EnSeal device or the RoBi clamp [11]. In brief, the patient was placed in a supine position under general anesthesia. The abdomen and vagina were disinfected, and a bladder catheter was inserted via the urethra. The Tintara uterus manipulator (Karl Storz), diameter 4 to 4.8 mm and length 50 to 80 mm, depending on uterus size, was introduced into the uterine cervix. The patient was draped and placed in a Trendelenburg position. After establishment of pneumoperitoneum using a Veress needle (insufflation of the abdomen using CO2) and insertion of the trocars, the uterus was inspected to enable preparation planes on both sides. The ongoing operation using one of the instruments followed a standard procedure. The cornual structures of the uterus (adnexa and round ligament) were transected, followed by dissection of the anterior and posterior layers of the parametrium. The broad ligament was prepared to enable visualization of the uterine artery and vein. Using the tension of the Tintara manipulator, the vesical peritoneum was dissected, resulting in dislocation of the vaginal fornices from the bladder and lateralization of the bladder pillars. The next steps were separation, coagulation, and cutting of the uterine artery and vein. At this stage of the procedure, the monopolar Brucker/Messroghli Supraloop (Karl Storz) was inserted through the suprapubic trocar, followed by supracervical dissection of the uterine corpus. The uterus was morcellated using the Unidrive Gyn with the Rotocut G1 system (Karl Storz) after coagulation of the remaining cervical canal (to prevent spotting) and closure of the peritoneum (if the length of the remaining cervix was %1 cm). The weight of the uterus was documented.

The relevant surgical steps achieved with both instruments in this comparative trial began with coagulation and transection of the cornual structures to prepare the cervical plane to enable cervical detachment. The number of coagulation and cutting steps for efficient preparation and vessel sealing was left to the discretion of the surgeon. In the control group, dissection of tissue was achieved using laparoscopic scissors (Karl Storz) after coagulation of the tissue. All operations and documentations were performed by the same surgeons (R.R., B.K., and W.Z.) The primary end point was resection time per instrument. The following times were documented: total operative time; T1, start of the operation to cornual structures ready to be dissected; T2, time from first coagulation and cutting of the cornual structures to complete preparation of each parametrial side directly before cervical detachment; and T3, time needed for cervical detachment and subsequent steps (morcellation and closure of trocar sites) to the end of the surgical procedure. Secondary end points were blood loss, postoperative pain, and complications. Perioperative blood loss (DHb) was calculated by comparing the number of preoperative red blood cells vs the number of red blood cells on postoperative day 1. Intraoperative blood loss was measured via the suction unit (,50, 50–100, and .100 mL) and the number of blood transfusions administered. Postoperative pain during hospital stay was documented according to a visual analog pain scale, from 1 (no pain) to 10 (maximum pain). Pain medication was administered according to the World Health Organization and the hospital stage scheme; aberrations and modifications were registered. Intraoperative complications (bleeding and injury of adjacent organs) and conversion to laparotomy were recorded. Follow-Up Follow-up to postoperative day 2 included documentation of serious adverse events, number of red blood cells, body temperature, blood transfusion, and length of hospital stay. After 28 days, patients were followed up via telephone for

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Table 3 Postoperative dataa 95% CI Variable

Experimental group

Control group

p value

Closure of peritoneum Yes No DHb (blood loss) (g%)

42 38 1.143 (0.82)

28 52 1.123 (0.86)

.03b

3.44 (1.62) (n 5 80) 2.03 6 1.49 (n 5 77) 2.13 (1.26) (n 5 8) 2.01 (0.44) 7 65 8

3.18 (1.71) (n 5 80) 1.96 6 1.38 (n 5 77) 1.59 (1.58) (n 5 17) 2.17 (0.47) 3 60 17

Pain scale Day 1 (n 5 160) Day 2 (n 5 154) Day 3 (n 5 25) Postoperative hospital stay (day) 1 2 3

Mean difference

Minimum

Maximum

.88c .56d

0.02

20.24

0.28

.28c

0.26

20.26

0.78

.95c

0.06

20.39

0.52

.12c

0.54

20.78

1.86

.03c

20.16

20.3

20.02

CI 5 confidence interval. a Values are given as number of patients or as mean (SD). b 2 c test (Pearson correlation coefficient). c Mann-Whitney U test. d A t test.

serious adverse events, infection, fever, postoperative vaginal bleeding, and hematoma. Statistical Analysis An a priori power calculation was performed using the two-sided nonparametric Wilcoxon rank sum test and considering a dropout rate of 10%. Descriptive statistics, specifically, means and standard deviations, were used for continuous variables and frequency counts, and percentages for nominal or categorical variables. All outcome data were analyzed according to intention to treat. Differences in categorized operative time and intraoperative blood loss between treatment groups were analyzed using the c2 test. Complication rates were compared using the Fisher exact test for small sample sizes. For independent samples, the Mann-Whitney test was used to compare non-normally distributed variables (operating time, postoperative pain, blood loss measured as DHb, and hospital stay) between groups. All p values were two-sided and not adjusted for the number of parameters evaluated; p , .05 was considered statistically significant. The statistical software used was SPSS Statistics, version 11.5 (SPSS, Inc., Chicago, IL). Results Intraoperative Data Insofar as the primary end point, mean (SD) total operative time for LASH was significantly shorter in the study group (78.18 [33.96] minutes vs 86.30 [35.34] minutes;

p 5 .03) (Table 2). The following times were measured in the experimental group vs the control group: T1 (time from start of operation to cornual structures ready to be dissected), 15.10 (5.51) minutes vs 16.21 (5.53) minutes (p 5 .19); T2 (time from first coagulation and cutting of the cornual structures to complete preparation of each parametrial side directly before cervical detachment), 24.90 (14.80) minutes vs 36.23 (25.44) minutes (p , .001); and T3 (time needed for cervical detachment and subsequent steps [morcellation and closure of trocar sites] to the end of the surgical procedure), 38.00 (22.25) minutes vs 33.86 (14.12) minutes (p 5 .42) (Table 2). In the experimental group, the mean (SD) weight of the uteri was 241.44 (213.48) g (maximum, 1360 g) was significantly greater than in the control group: 177.33 (137.52) g (maximum, 868 g) (p 5 .04) (Table 3). Documented blood loss was ,50 mL in 72 patients in the experimental group vs 62 patients in the control group (p 5 .03), and was 50 to 100 mL in 8 patients in the experimental group vs 18 patients in the control group (p , .001). Greater blood loss was not documented with use of either instrument. No blood transfusions were necessary during the perioperative phase or follow-up. Mean (SD) postoperative hospital stay was significantly shorter for patients in the experimental group vs the control group: 2.01 (0.44) days vs 2.17 (0.47) days (p 5 .03). There was a correlation between hospital stay and uterus size (r 5 0.17; p 5 .04). There was no difference in postoperative pain scores between the two treatment groups.

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Complications No conversions to laparotomy were recorded in either study group. No complications were observed in the experimental group during follow-up of 28 days; however, one patient underwent revision surgery after 35 days because of severe bleeding from the peritonealized cervix. During follow-up, two complications occurred in the control group: a hematoma of the trocar site in one patient and symptomatic adhesions and elevated temperature due to pelvic inflammatory disease in another patient. Discussion Although a variety of energy sources and electrosurgical instruments are commercially available for minimally invasive surgical procedures in gynecology, the optimal device has not yet been found. To our knowledge, the present study is the first prospective randomized trial that comprehensively investigated clinical parameters for the EnSeal device including operative time, blood loss, and short-term complications. The EnSeal instrument enables sealing and cutting, which presumably has an influence on operative time and workflow of the procedure because repeated changing between a standard laparoscopic electrocoagulation instrument and scissors is not applied. In our study collective, which is comparable to other studies of hysterectomy procedures, use of the EnSeal device reduced total operative time, and the other investigated clinical parameters were not inferior compared with those in the control group [12]. If surgical steps T1 (from start of the operation to cornual structures ready to be dissected), T2 (time from first coagulation and cutting of the cornual structures to complete preparation of each parametrial side directly before cervical detachment), and T3 (time needed for the cervical detachment and subsequent steps [morcellation and closure of trocar sites] to the end of the surgical procedure) are investigated individually, this finding becomes even more evident, in particular because T2 represents the time frame in which the EnSeal device can be used most effectively and without the time-consuming changing of instruments as in the control group. T1 and T3 were not significantly different, although T1 was slightly shorter in the experimental group, which again reflects the possibility of convenient minor adhesiolysis before the actual dissection of the cornual structures without changing instruments. A substantial advantage insofar as time needed for extensive adhesiolysis was not investigated because cases were excluded from the study if .5 coagulation and cutting steps for adhesiolysis were necessary. T3, in which the electrocoagulation devices are usually not used any more, was longer in the experimental group. T3 was correlated with uterus size, and therefore the time difference can be explained by protracted morcellation of uteri that were substantially larger in the experimental group. In addition, in the experimental group, the peritoneum above the cervical stump was closed more often

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because of larger uteri and myomas reaching down to the cervix, which explains the longer T3. We are aware that operative time and uterus weight are generally dependent on the patient collective, surgeon experience, and hospital conditions. However, total operative time and uterus weights given in this article are comparable to those in previously published studies of laparoscopic hysterectomy [12,13]. The investigated values for intraoperative and perioperative blood loss are not definite. Insofar as total intraoperative blood loss, which was scaled by the surgeon, a substantial advantage was documented in the experimental group; however DHb did not yield statistical significance. Blood loss of DHb 1 g% usually equals 300 to 350 mL. On the basis of DHb, mean blood loss was w300 mL, which was never estimated by the surgeons with respect to the intraoperative scale .100 mL. This indicates that evaluation of intraoperative blood loss and hemostasis is left to the surgeon’s subjective discretion, experience, and learning curve, which is a limitation of the present investigation and of surgical studies in general. Insofar as postoperative pain, there was no statistically significant difference between the collectives. However, hospital stay was significantly shorter in the study group, which is remarkable because hospital stay correlates with uterus size, and this was larger in the study group. Consequently, a mediator variable can be postulated that relates to the device. Our findings in this study are in concordance with the current literature that reports clinical use of the EnSeal device and its positive sealing characteristics in comparison with other energy-based devices [8,14–16]. Shorter operative time and less blood loss in the study group of an animal model have been reported by Overhaus et al [17]; however, they compared the device with the conventional clamp and ligation technique when bowel and kidney resections were performed. According to a metaanalysis that investigated the outcome of energy-based coagulation and cutting devices in prospectively randomized studies, operative time, blood loss, and complications were decreased [16]. The primary end point of our study (operative time) is in concordance with these results, although decreased blood loss and fewer complications could not be demonstrated. In conclusion, total resection time was lower in the experimental group, and the other investigated clinical parameters were not inferior in the experimental group compared with the control group. Our results indicate that in LASH, the EnSeal device is at least as reliable as the conventional electrocoagulation technique. References 1. Abdelmonem A, Wilson H, Pasic R. Observational comparison of abdominal, vaginal and laparoscopic hysterectomy as performed at a university teaching hospital. J Reprod Med. 2006;51:945–954. 2. Hobson DT, Imudia AN, Al-Safi ZA, et al. Comparative analysis of different laparoscopic hysterectomy procedures. Arch Gynecol Obstet. 2012;285:1353–1361.

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