2747
Views & Citations1747
Likes & Shares
Objective: To determine
which mode and potency of electrocoagulation, using a modern electrosurgical
generator, yields the smallest unobstructed area of the fallopian tubes.
Methods: In a
cross-sectional study, tubes from 48 hysterectomies were evaluated. Tubes were
randomly allocated to one of the following groups: A-25Wx5 sec, n=17; B-30Wx5
sec, n=17; C-35Wx5sec, n=18, D-40W, 5 sec, n=20; E-40W visual inspection
(blanch, swells, collapse), n=16; F-50Wx5 sec, n=8. Bipolar electrocoagulation
was applied in groups A to E, and unipolar electrocoagulation was performed in
group F. Coagulation mode was used in all groups. Transversal histological sections
of the isthmic segment of the fallopian tube were digitally photomicrographed
and luminal area (mm2) was measured with ImageJ software. Kruskal-Wallis or
ANOVA tests were used for statistics.
Results: Ninety-six
fallopian tube sections were analyzed. Median [range] non-occluded area (%) of
each group was: A= 0.12[0 to 3.96], B= 0.17[0.01 to 3.3], C= 0.33[0.03 to
4.61], D= 0.22[0 to 3.53], E= 0.27[0.01 to 1.45] and F=0.94[0.08 to 2.67]. No
statistical significance was found (p=0.3 - Kruskal-Wallis test)
Conclusion: Different
potencies of bipolar or unipolar, using a modern electrosurgical generator,
yielded no significant difference among groups in the unobstructed area of
fallopian tubes.
Keywords: Fallopian tube,
Electrocoagulation, Tubal ligation, Tubal occlusion, Bipolar, Unipolar
Synopsis: In the coagulation mode, different
coagulation modes > 25 W do not produce significant differences in the
occluded area.
INTRODUCTION
Tubal ligation is an effective form of permanent female contraception. In the World, it is the most commonly used method of contraception, being the method selected by 19% of women aged 15 to 49 who are married or in union [1]. In the United States, it is the second most commonly used form of contraception [2]. Among the different methods of tubal ligation, the unipolar electrocoagulation has the lowest long-term failure rate, but has been associated with thermal injury to the bowel and is rarely used [3]. Laparoscopic bipolar coagulation is a safe technique and, according to the American College of Obstetricians and Gynecologists (ACOG) practice bulletin, at least 3 cm of the isthmic portion of the fallopian tube must be completely coagulated [3].
The use of inline ammeter is not
recommended or mentioned by the Brazilian Health Ministry, by the Brazilian
Federation of Gynecologists and Obstetricians (FEBRASGO), or by the Argentinian
Health Ministry. Therefore, it is necessary to provide evidences if the current
practice of tubal ligation without inline ammeter, using the bipolar mode in a
modern electrosurgical generator, deliver enough energy to collapse the lumen
of the fallopian tube. The objective of this study is to verify which mode and potency of electrocoagulation,
using a modern electrosurgical generator, attains adequate sterilization
without the use of an ammeter.
MATERIAL AND METHODS
The institutional review board of Hospital de Clínicas de Porto Alegre
and of the Hospital Femina de Porto Alegre approved this cross-sectional study.
Inclusion criteria consisted in women with normal fallopian tubes that would be
submitted to surgery. From April 2010 until December 2011, consecutive women
scheduled for hysterectomy or tubal ligations were asked to permit use of the
product of the hysterectomy for this study.Women who did not give written
consent, those who had gynecologic cancer, hydrosalpinx, isthmic segment of the
fallopian tube < 3cm, or abnormal anatomy of the fallopian tube were excluded.
The procedures were done by one of the authors (MIC), or by another surgeon
previously instructed about the protocol. During the procedure, each tube was
randomly allocated to one of the following groups: A-25W x 5 sec; B-30W x 5
sec; C-35W x 5sec; D-40W, 5 sec; E-40W visual inspection (blanch, swells,
collapse); F-50W x 5 sec. Randomization list was generated by a computer
software. The randomized list was kept in sequenced sealed envelope, which was
opened at the beginning of the surgery. All groups used the coagulation mode,
because cutting mode is not possible in bipolar electrocoagulation. Bipolar
electrocoagulation was applied in groups A to E, and unipolar
electrocoagulation was performed in group F.
Electrocoagulation was performed in the coagulation mode using the WEM
Model SS-501S electrosurgical generator (WEM Equipamentos Eletrônicos Ltda,
Ribeirão Preto, SP, Brazil) with the Bipolar (Ref. 14.1048, EDLO, Canoas, RS,
Brazil), or the unipolar forceps (Ref. 12231, Rhosse, RibeirãoPreto, SP, Brazil).
Bipolar coagulation of the tubes was performed on an auxiliary table after the
uterus was removed. Due to the characteristics of unipolar system,
electrocoagulation of the fallopian tubes was performed before the removal of
the uterus. Unipolar coagulation was considered as a control and was limited to
8 samples.
Fulguration of the tubes was performed on three contiguous areas, at
least 3cm in length, as recommended in the literature [7].
Histology and analysis of the
occluded area
Coagulated tubes were resected and fixed in formaldehyde 10% for
histological analysis and embedded in paraffin. Paraffin blocks were cut 4 µm
thick and were stained with hematoxylin and eosin. Four transversal sections
were obtained from each block and analyzed by microscopy. The section with the
highest thermal injury, according to Soderstrom et al. [5], was chosen for digital photomicrography. Digital
pictures were taken using an Olympus BX51 microscope (Olympus Optical Co.,
Tokyo, Japan) connected to a digital color camera/Q-Color 5 (Olympus). Images
were obtained with a 4X objective UPL an FI (resolution: 2.75μm), at a size of
2560x1920 pixels (resolution: 1mm = 590 pixels), under standard lighting
conditions.
ImageJ analyses
In order to reduce bias, each slide
was coded and the open lumen area (mm2) and percentage were blindly
analyzed for the outcomes: luminal area (mm2) and percentage of area
open in the lumen. These outcomes were analyzed with ImageJ software (ImageJ
v1.43j; National Institutes of Health, Bethesda, MD, USA available at
http://rsbweb.nih.gov/ij/). Briefly, a circle was drawn around the lumen of the
fallopian tube. The outside area was cleared and the image was converted into 8
bits. The image was adjusted for a threshold, using a dark background. Next,
the region of interest (ROI manager) was activated and saved in a file. From
the ROI manager, the software calculated the total and relative open area of
the section.
Sample size, statistical analysis and ethical issues
Sample size was calculated based on
data previously published [5] and using the formula described in the literature
[7]. The following parameters were used: an alpha error of 0.05, power of 0.8,
total occlusion of the lumen (100%) using bipolar coagulation at 35 W, a
reduced occluded area (85%) with lower potencies, and a standard deviation of
10. These figures yielded a sample size of a minimum of 8 cases in each group.
GraphPad Prism version 6 for
Macintosh (GraphPad Software, Inc., San Diego, California, USA) was used for
statistical analysis of the variables, using the Kruskal-Wallis test. AP<0.05 considering significant. This study was submitted and
approved by Comitê de Ética em Pesquisa –
Hospital de Clínicas de Porto Alegre and Grupo Hospitalar Conceição.
RESULTS
Fifty-nine women were invited to participate in the study, and 11 were excluded (6 had a short isthmic segment; 5 had abnormal anatomy of the fallopian tube). Forty-eight women, i.e., 96 fallopian tubes, were submitted to bipolar or unipolar coagulation. Characteristics of the population are depicted in Table 1. No significant difference was observed among groups, either in total or relative area due to the high variability (Figure 1). Although not significantly different from the other groups, the highest mean occluded area of the fallopian tube was obtained in group E (40 W visual inspection). In average, this method did not occluded 8.3% (95%CI: 5.4 to 16.5) of lumen of the fallopian tube. The mean ± SD time of coagulation for each grasp in group F (40 W visual) was 3.8±1 seconds. The highest open area was obtained with the unipolar method 29.5% (95%CI: 13.5 to 45.5).
DISCUSSION
The new feature of modern
electrosurgical generators, where constant electronic adjustments provide
constant power through different tissue changes, leads us to investigate if
total fulguration of the fallopian tube could be achieved without the use of an
inline ammeter.
In this study, we used different potencies and modes and we were not able to find any statistical difference among groups. The bipolar mode, independently of the wattage used, yielded a median occluded area of over 85%, while the 40 W with visual inspection provided around 92% of occlusion (Figure 1). These data are in accordance to those published in the literature [5]. The bursts of high-peak voltage desiccate the outer layers of the tube too quickly and prevent deep penetration by the electrons delivered. This high-peak voltage may explain the lowest coagulation area (around 61%) obtained with unipolar coagulation, which used 50W. Nevertheless, it is possible to achieve complete coagulation of the lumen with bipolar mode, using ≥25W for 5 seconds (Figure 1).
Based on our findings, it is
possible to identify that total occlusion of the fallopian tube is feasible
without the use of inline ammeter, which is incorporated with most bipolar
generatorsin the US [8]. The importance of inline ammeter lies on the
recognition that the fallopian tube is totally coagulated [5].This
recommendation is based from a review of 2267 procedures done before 1987,
where failures on tubal ligation were observed [6]. In 1989, Soderstrom et al., using 5 tubes derived from
hysterectomy, demonstrated that bipolar system using 35 W in the coagulation
mode yielded complete coagulation of the fallopian tube. Likewise, using 20
tubes, complete coagulation of the fallopian tube was obtained with 25 W in the
cutting mode. These results were based on a Kepplinger and Valley lab
generators [5].
Modern electrosurgical generators
have electronic adjustments, which provide constant power through different
tissue changes, and can offer up to 40W. In addition, these new modern
electrosurgical generators do not offer “pure cut” in the bipolar mode, thus
the use of an inline ammeter is necessary to indicate when the current through
the fallopian tube has ceased flow.
Unfortunately, inline ammeters are
not sold in Brazil, and the only orientation given by the Brazilian Health
Ministry on tubal ligation is that the procedure should be performed with
bipolar mode [9]. This lack of details could be related to the evolution of the
electrosurgical generator units. New electrosurgical generators have a
computer-controlled tissue feedback response system that senses tissue
impedance and corrects the energy flow [10]. In addition, the report that
bipolar coagulation system was highly effective for bilateral tubal ligation,
if a segment of ≥3 cm was coagulated [4], may contribute to the lack of details
given by the Brazilian Health Ministry, and from other institutions, such as
the Argentinian Health Ministry [11] and the Brazilian Federation of
Gynecologists and Obstetricians (FEBRASGO) [12].
The strengths of this study are the
calculated sample size and the use of ImageJ software to quantify the
unobstructed area of the fallopian tube. ImageJ provides an unbiased quantification
of the open area, and this approach seems to be superior to visual inspection.
Initially, we used the histological grading described by Sodestrom et al. [5],
but the high inter- and intraobserver variation (data not shown) led us to use
the ImageJ software. Hopefully, this method can be the gold standard to
quantify the open lumen.
The main weakness of the study is
its lack of external validity. Just one electrosurgical generator was used, so
no extrapolations can make to other models. Another aspect is the degree of
thermal injury. The histological analysis was done after the electrocoagulation
was performed. It has been shown that complete occlusion may take up to 8 weeks
to occur [13]. Therefore, our data may underestimate the real rate of the tubal
occlusion.
This study brings new data about
the unipolar occlusion rate that was thought to be the best method for tubal
occlusion. In addition, it provides evidence that new generators can cause
total occlusion of the fallopian tube. New settings for tubal fulguration, such
as lower wattage and longer time may, be sought to reach the best occlusion
rate without using an inline ammeter.
In summary, the modern
electrosurgical generator used herein yielded similar degree of damage on the
fallopian tube independently of the mode and potency used. These results may help to develop guidelines
in places with low resource.
ACKNOWLEDGEMENT
Fundação de Incentivo a Pesquisa e Ensino (FIPE) – Hospital de Clínicas de Porto Alegre.
- United
Nations (2011) World contraceptive use, 2011.
- Zite N,
Borrero S (2011) Female sterilisation in the United States. Eur J
Contracept Reprod Health Care. 16: 336-340.
- ACOG
(2013) Practice bulletin no. 133: benefits and risks of sterilization.
Obstet Gynecol. 121: 392-404.
- Hulka JF,
Reich R (1994) Sterilization techniques: Hulka JF, Reich H, editors.
Textbook of laparoscopy. 2nd. Philadelphia: W.B. Saunders Co.
- Soderstrom
RM, Levy BS, Engel T (1989) Reducing bipolar sterilization failures.
Obstet Gynecol. 74: 60-63.
- Julious
SA (2004) Sample sizes for clinical trials with normal data. Stat Med 23:
1921-1986.
- Hoffman
BL, Schorge JO, Schaffer JI, Halvorson LM, Bradshaw KD, Cunningham FG, et
al. (2014) Minimally Invasive Surgery. Williams Gynecology.
- Peterson
HB, Xia Z, Wilcox LS, Tylor LR, Trussell J (1999) Pregnancy after tubal
sterilization with bipolar electrocoagulation. U.S. Collaborative Review
of Sterilization Working Group. Obstet Gynecol 94: 163-167.
- Brazil,
Health Ministry. Secretary of Health policies (2002) Technical area of
women's health. Family planning: technical manual/Secretary of policy of
health, Technical area of Women's health]. Standards and Technical manual.
- Advincula
AP, Wang K (2008) The evolutionary state of electrosurgery: where are we
now? Curr Opin Obstet Gynecol 20: 353-358.
- Trumper
E, Provenzano B, Prigoshin P (2009) Health Ministry of the Nation
(Argentina)-Scientific document-tubal ligation.
- Poli MEH, Mello CR, Machado RB,
Pinho Neto JS, Spinola PG, Tomas G, et al. (2009) FEBRASGO - Manual
of Contraception. Femina 37: 459-492.
- Tucker
RD, Benda JA, Mardan A, Engel T (1991) The interaction of electrosurgical
bipolar forceps and generators on an animal model of fallopian tube
sterilization. Am J Obstet Gynecol 165: 443-449.
QUICK LINKS
- SUBMIT MANUSCRIPT
- RECOMMEND THE JOURNAL
-
SUBSCRIBE FOR ALERTS
RELATED JOURNALS
- Journal of Agriculture and Forest Meteorology Research (ISSN:2642-0449)
- Advances in Nanomedicine and Nanotechnology Research (ISSN: 2688-5476)
- Journal of Genetics and Cell Biology (ISSN:2639-3360)
- Journal of Microbiology and Microbial Infections (ISSN: 2689-7660)
- Journal of Genomic Medicine and Pharmacogenomics (ISSN:2474-4670)
- Journal of Biochemistry and Molecular Medicine (ISSN:2641-6948)
- Proteomics and Bioinformatics (ISSN:2641-7561)