Cervical priming prior to operative hysteroscopy: a randomized comparison of laminaria versus misoprostol

A.M. Darwish1, A.M. Ahmad and A.M. Mohammad

Department of Obstetrics and Gynecology, Assiut University Hospital, Assiut, Egypt

1 To whom correspondence should be addressed at: Gynecologic Endoscopy Unit, Department of Obstetrics & Gynecology, Assiut School of Medicine, Egypt. Email: a_darwish{at}mailcity.com


    Abstract
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
BACKGROUND: We aimed to compare efficacy of intravaginal misoprostol versus endocervical laminaria tents prior to operative hysteroscopy in selected cases. METHODS: A total of 144 patients with diagnosed intrauterine lesions scheduled for operative hysteroscopy were randomly allocated to two groups according to method of cervical priming prior to the procedure. Misoprostol 200 µg was inserted into the posterior fornix of the vagina for patients in group A (n=72), while laminaria tents were inserted intracervically in group B patients (n=72). RESULTS: Both methods were effective for cervical dilatation with a mean cervical diameter of 7.5±1.2 and 7.6±1.2 mm respectively. There was no significant difference in the mean cervical diameter or the time required for cervical dilatation (51.6 versus 51.4 s respectively). In contrast, there was a significant difference between the groups with respect to the insertion difficulty and in doctors' and patients' assessments of the procedure. CONCLUSIONS: Both misoprostol and laminaria were equally effective in inducing proper cervical priming prior to operative hysteroscopy with minimal time of cervical dilatation. Nevertheless, misoprostol may be superior due to easy application, reduced cost, and patient convenience and acceptability.

Key words: hysteroscopy/laminaria/misoprostol


    Introduction
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Operative hysteroscopy has gained popularity as a minimally invasive approach to intrauterine lesions (Siegler and Valle, 1988Go). Cervical dilatation represents a real challenge during operative hysteroscopy, particularly in nulligravidae, post-menopausal women and women with cervical stenosis. Furthermore, some lengthy hysteroscopic operations such as myomectomy require adequate cervical dilatation to facilitate repeated insertions and withdrawals of the resectoscope. Another technical problem is the need for a considerable degree of cervical dilatation as well as softening to allow complete extraction of the excised endouterine lesions.

Misoprostol is a prostaglandin E1 analogue which is commonly used in obstetrics for induction of abortion and labour as well as postpartum to control vaginal bleeding (Bugalho et al., 1994Go). Its utilization in gynaecology has been limited. It was recently used prior to artificial insemination and operative hysteroscopy. Vaginal misoprostol applied before operative hysteroscopy has reduced the need for cervical dilatation, facilitated hysteroscopic surgery and minimized cervical complications (Preutthipan and Herabutya, 1999Go).

On the other hand, laminaria tents, made from the stems of Laminaria japomica or Laminaria digitata (brown sea weed), are attractive natural substances that can cause cervical dilatation with minimal local and no systemic side-effects. They have been shown to be effective in inducing cervical priming prior to operative hysteroscopy (Ostrzenski, 1994Go). However, there have been no comparative studies of the efficacy of the two methods for cervical priming (Sowter et al., 2003Go). The aim of this work was to compare efficacy of intravaginal misoprostol versus endocervical laminaria tents prior to operative hysteroscopy in selected cases.


    Materials and methods
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
This study was carried out at the Gynecologic Endoscopy Unit, Assiut University Hospital from February 2002 to July 2003. It was approved by the Medical Ethics Committee of the Faculty of Medicine. All patients gave a written consent. The study comprised 144 patients recruited from the Gynaecology, Infertility, and Family Planning Clinics with different indications for operative hysteroscopy (Table II). Inclusion criteria included nulliparous or multiparous women with primary or secondary cervical stenosis (defined as difficult or failed cervical sounding in the office) who were scheduled for operative hysteroscopy.


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Table II. Main complaints (indications for hysteroscopy)

 
Selected cases had a full history, thorough general and pelvic examinations, and transvaginal ultrasonography to determine the nature, site and extent of intrauterine lesions. Patients were randomly divided into two groups. Group A (72 cases) received 200 µg misoprostol (Misotac; Sigma Co., Egypt) into the posterior fornix 8 h prior to surgery. Patients in group B (72 cases) received a single laminaria (Med Gyn Products, Inc., USA) as fine as 2 mm inserted into the cervical canal. The patient was put in the dorsal lithotomy position, where a sterile Cusco's speculum was applied and the cervix was sterilized using Bovidone iodine solution. The laminaria was removed aseptically from its package and grasped from its proximal end where the string is attached using Ring forceps. It was inserted into the cervical canal until it passed the internal os with the string resting in the vaginal vault for easy removal. In the operating room, the degree of initial cervical dilatation was assessed by introducing Hegar dilators under general anaesthesia. It was defined as the maximal calibre dilator that passed without resistance in a descending order, starting with the largest size dilator. The duration of subsequent cervical dilatation until reaching 10 mm, and feasibility of the procedure, were recorded. Cervical canal dilatation complications (false passage or perforation) were reported. At the end of the procedure, we recorded doctor assessment in the form of feasibility of the hysteroscopic operation, and patient impression in the form of insertion difficulties, convenience and fear of either method. All operations were done by only three members of the Endoscopic Unit with a comparable level of experience.

Sample size estimation was adequate to detect a difference of 3.2 mm (type I error of 0.01) with a power of 0.99. As a result, 144 cases were included in this study. Randomization was done by means of sealed envelopes. It was a double-blind randomization study in that the evaluator (first author) masked the key from the researcher (third author) to avoid bias. Collected data were revised and coded for computerized data entry. A data entry file was created on EPI Info version 9. After complete data entry, the file was converted to an SPSS file. Analysis was undertaken using SPSS version 11 and expressed as mean±SD. Statistical methods were applied including descriptive statistics (frequency, percentage, mean and SD) and tests of significance [two-tailed Student's t-test, analysis of variance (ANOVA) and {chi}2]. P<0.05 was considered statistically significant.


    Results
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
One hundred and forty-four patients who fulfilled the inclusion criteria were randomized. There was no statistically significant difference between the groups for age and parity (Table I), indications (Table II), and type of surgery (Table III) of operative hysteroscopy. Primary or secondary infertility were the main indications in 38 (52.8%) and 38 (52.71%) patients in both groups respectively due to a suspected intrauterine cause as diagnosed by transvaginal scan (TVS) or hysterosalpingography (HSG).


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Table I. Demographic data of the patients

 

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Table III. Hysteroscopic procedures in both groups

 
Technical details and disadvantages of both methods of cervical priming are demonstrated in Tables IV and V. Two cases of cervical perforation in group A were treated conservatively. Doctor and patient's comments on the method of priming are reported in Table VI.


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Table IV. Technical characteristics of the two studied groups

 

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Table V. Disadvantages of the procedure

 

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Table VI. Doctor assessment and patient acceptability of cervical priming

 

    Discussion
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
One of the major problems of hysterosocpic surgery is difficulty in entering the internal cervical os with the outer sheath of the operative hysteroscope or the resectoscope. Traditional cervical dilatation using Hegar's dilators may not be feasible in some patients with very tight cervix or cervical abnormalities regardless of the parity of the patient. That is why we included a heterogeneous group of patients with respect to parity. However, all patients had difficult or failed sounding, with no significant difference between both groups. In a previous study, three cases of uterine perforation had occurred during endometrial ablation, where difficulty in cervical dilatation was the predisposing factor in one case (Itzkowic and Beale, 1999Go). In a large sample size study of 800 hysteroscopic endometrial ablations (Vilos et al., 1996Go), the overall complication rate was 3.9%. Cervical trauma and uterine perforation were the most common complications. Obviously, cervical priming would have a central role in facilitating the procedure. Trials of cervical priming started as early as 1985 where intracervical sulprostone gel was applied before diagnostic hysteroscopy which led to a significant reduction in the force required to dilate the cervix (Rath et al., 1985Go). Likewise, the vaginal use of metenoprost potassium before outpatient hysteroscopy in infertile patients provided sufficient dilatation of the cervical canal to permit the insertion of a hysteroscope without additional mechanical dilatation (Hald et al., 1988Go). Oral misoprostol was compared with placebo for cervical priming before diagnostic hysteroscopy (Ngai et al., 1997Go) with a significant reduction in the amount of force required to dilate the cervix to 8 mm (40.1 compared with 103.7 newtons, P<0.001). The mean baseline cervical dilatation was significantly greater in the misoprostol group (6.0 compared with 3.3 mm, P<0.001). However, it produced a non-significant beneficial effect in post-menopausal women whether given orally (Ngai et al., 2001Go) or vaginally (Fung et al., 2002Go). In practical terms, those patients obtain a definite benefit from cervical priming using misoprostol, which causes cervical softening (Wing and Paul, 1996Go). In this study, we included nine post-menopausal women who had successful cervical priming. In a recent study (Thomas et al., 2002Go), misoprostol demonstrated a benefit compared with placebo in the ease of cervical dilatation in pre-menopausal and post-menopausal women and in those pretreated with a GnRH analogue. A randomized double-blind study comparing the effectiveness of vaginal misoprostol versus placebo for cervical dilatation found that the baseline cervical dilatation was significantly greater with shorter duration of dilatation in the treatment group (Preutthipan and Herabutya, 1999Go).

Laminaria is a sea-grown plant that swells in the presence of liquid. It has been found to provide a fast and adequate cervical dilatation prior to transcervical removal of submucous leiomyoma (Townsend and Melkonian, 1990Go) and to reduce significantly the frequency of inadequate cervical dilatation before resectoscopic surgery (Ostrzenski, 1994Go).

Laminaria was evaluated in 300 patients before diagnostic or operative hysteroscopy (Townsend and Melkonian, 1990Go). A 5 mm diagnostic hysteroscopy was performed 2–3 h after insertion, while a 9 mm operative resectoscope was inserted ~24 h after insertion of the laminaria tent. There were no complications with the use of laminaria tents such as infection or bleeding, but some patients complained of mild menstrual-like lower abdominal discomfort. In all cases, laminaria resulted in softening and dilatation of the cervix, which facilitated the passage of the diagnostic and opertive hysteroscopes. In this study, we reported 26 cases of insertion difficulties, explaining a highly significant patient inconvenience with insertion of laminaria (Table V). To determine its efficacy, laminaria were used prior to hysteroscopic adhesiolysis of severe intrauterine synechiae in seven patients with secondary amenorrhoea due to severe uterine synechiae diagnosed by HSG and hysteroscopy (Chen et al., 1997Go). The uterine cavity appeared short, narrow and scarred coned or column-shaped. Not only did the women achieve normal menstruation, but also a normal uterine cavity as confirmed by subsequent HSG or hysteroscopy. In addition, three patients became pregnant, two of whom have had successful term deliveries. Misoprostol is a chemical method with a systemic absorption of the drug whereas laminaria tents act by a mechanical dilatation.

We did not find any randomized comparative studies of the two methods of cervical priming. In this study, we found that both were effective in dilating the cervix with a mean cervical width of 7.6±1.2 and 7.5±1.2 mm respectively. There was no significant difference between laminaria and misoprostol with regard to the mean cervical width or the time required for cervical dilatation. In contrast, there was a significant difference between laminaria and misoprostol with regard to insertion difficulty and doctors' and patients' satisfaction with the procedure. The time required for cervical dilation up to Hegar 10 was longer in both groups (51.6 s for misoprostol and 51.4 s for laminaria) compared to previous studies (Ostrzenski, 1994Go; Preutthipan and Herabutya, 1999Go). This may be due to inter-observer variability as we included all cases done by three hysteroscopists in the Unit. A significant difference in cervical injury between misoprostol and placebo was found in a previous study (Preutthipan and Herabutya, 1999Go). They reported one (1.4%) cervical tear in the treated group compared with nine patients (11.4%, P=0.018) in the control group, seven of whom required suturing. Recently, three cases of extensive cervical laceration that lead to inability to perform hysteroscopy and two cases of retroperitoneal installation of the distending media due to lateral cervical laceration were reported in one study (Ghazizadeh, 2003Go). In our study, two cases of cervical perforation occurred during myomectomy in the misoprostol group, while no case of perforation was encountered in the laminaria group.

From this study, it is concluded that both laminaria and misoprostol were shown to be effective in inducing adequate cervical priming prior to operative hysteroscopy with minimal time of cervical dilatation. Nevertheless, misoprostol is superior as it has the following advantages: easy application (it can be inserted by the patient herself at home), cheaper price (one tablet costs $0.2 versus $5 for each laminaria piece), more economic (eliminates the charge of insertion in the office or the hospital), patient convenience (saves time and the expense of attending clinics or hospital for insertion without requiring time off work), and greater acceptability. More studies are needed to compare misoprostol and laminaria with placebo before recommending routine cervical priming prior to operative hysteroscopy in selected cases. Furthermore, the need for sequential applications of laminaria of increasing diameters rather than a single application requires further study.


    References
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Bugalho A, Bique C, Machungo F and Faunder A (1994) Induction of labor with intravaginal misoprostol in intrauterine fetal death. Am J Obstet Gynecol 171, 538–541.[ISI][Medline]

Chen FP, Soong YK and Hui YL (1997) Successful treatment of severe uterine synechiae with transcervical resectoscopy combined with laminaria tent. Hum Reprod 14, 943–947.[CrossRef]

Fung TM, Lam MH, Wong SF and Ho LC (2002) A randomized placebo controlled trial of vaginal misoprostol for cervical priming before hysteroscopy in postmenopausal women. Br J Obstet Gynaecol 109, 561–565.

Ghazizadeh S (2003) Complications of operative hysteroscopy, report of rare cases. Proceedings of the 12th Annual Congress of the European Society for Gynecologic Endoscopy, Luxemburg, November 26–29, p 88, 006.

Goldrath MH (1987) Vaginal removal of the pedunculated submucous myomata. The use of laminaria. Obstet Gynecol 70, 670.[Abstract]

Hald F, Kristoffersen SE and Gregresen E (1988) Prostaglandin vaginal suppositories in nonpregnant women required cervical dilatation prior to hysteroscopy. Acta Obstet Gynecol Scand 67, 219–222.[ISI][Medline]

Itzkowic D and Beale M (1999) Uterine perforation associated with endometrial ablation. Aust NZ J Obstet Gynecol 32, 359–361.

Ngai SW, Chan YM and Ho PC (2001) The use of misoprostol prior to hysteroscopy in postmenopausal women. Hum Reprod 16, 1486–1488.[Abstract/Free Full Text]

Ngai WN, Chan YM, Liu KL and Ho PC (1997) Oral misoprostol for cervical priming in non pregnant women. Hum Reprod 12, 2373–2375.[Abstract]

Ostrzenski A (1994) Resectoscopic cervical trauma minimized by inserting laminaria digita preoperatively. Int J Fertil Menopausal Stud 111, 39.

Preutthipan S and Herabutya Y (1999) A randomized controlled trial of vaginal misoprostol for cervical priming before operative hysteroscopy. Obstet Gynecol 94, 427–430.[Abstract/Free Full Text]

Rath W, Kuhn W and Hilgers R (1985) Facilitation of cervical dilatation by intra cervical application of sulprostone gel prior to hysteroscopy. Endoscopy 17, 191–193.[ISI][Medline]

Siegler AM and Valle RF (1988) Therapeutic hysteroscopic procedures. Fertil Steril 50, 685–699.[ISI][Medline]

Sowter MC, Lethaby A and Singla AA (2003) Preoperative endometrial thinning agents before endometrial destruction for heavy menstrual bleeding (Cochrane Review). In The Cochrane Library, Issue 2. Update Software, Oxford.

Thomas JA, Leyland Y, Durand N and Windrim RC (2002) The use of oral misoprostol as a cervical priming agent in operative hysteroscopy: a double-blind, placebo-controlled trial. Am J Obstet Gynecol 186, 876–879.[CrossRef][ISI][Medline]

Townsend DE and Melkonian R (1990) Laminaria tent for diagnostic and operative hysteroscopy. J Gynecol Surg 6, 271–274.[ISI][Medline]

Vilos GA, Vilos EC and King JH (1996) Experience with 800 hysteroscopic endometrial ablations. J Am Assoc Gynecol Laparosc 4, 33–38.[ISI][Medline]

Wing DA and Paul RH (1996) A comparison of differing dosing regimens of vaginally administered misoprostol for preinduction cervical ripening and labor induction. Am J Obstet Gynecol 175, 158–164.[ISI][Medline]

Submitted on December 8, 2003; resubmitted on January 22, 2004; accepted on June 7, 2004.





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