The primary purpose of fallopian tube patency examinations is to assess whether the fallopian tubes are open, determine the morphology of the uterine cavity and fallopian tube lumen, and identify the location of any obstruction within the fallopian tubes. Common methods include tubal hydrotubation and hysterosalpingography, which may also have therapeutic benefits. With the widespread application of endoscopy in obstetrics and gynecology, laparoscopic tubal hydrotubation and hysteroscopic hydrotubation have become increasingly common.
Tubal Hydrotubation
Tubal hydrotubation is a procedure in which fluid is injected into the uterine cavity through a catheter. The patency of the fallopian tubes is determined based on the level of resistance, the presence or absence of fluid reflux, the volume of fluid injected, and the sensations experienced by the patient. This procedure is straightforward and does not require special equipment.
Indications
These include:
- Infertility cases where the male partner has normal semen analysis and fallopian tube obstruction is suspected.
- Evaluation of the effectiveness of tubal sterilization, tubal recanalization, or tubal reconstructive surgery.
- Removal of mild adhesions within the fallopian tube mucosa.
Contraindications
These include:
- Acute or subacute genital tract infections, or pelvic inflammatory disease.
- Menstrual period or irregular vaginal bleeding.
- Suspected pregnancy.
- Severe systemic diseases that make the procedure intolerable for the patient.
- Body temperature exceeding 37.5°C.
Preoperative Preparation
The procedure is performed 3–7 days after the end of menstruation, and refrain from sexual activity for three days prior to the procedure.
An intramuscular injection of 0.5 mg atropine is administered 30 minutes before the procedure to relieve spasms.
The bladder is emptied before the procedure.
Procedure
Instruments
Commonly used instruments include a vaginal speculum, cervical tenaculum, gynecological forceps, cervical catheter, Y-shaped tube, pressure gauge, and syringe.
Solution
Common solutions include saline or antibiotic solutions (e.g., gentamicin 80,000 U, dexamethasone 5 mg, hyaluronidase 1,500 U in 20 mL of sterile water for injection). A 0.5% lidocaine solution (2 mL) may be added to reduce tubal spasms.
Steps
The patient is positioned in the bladder lithotomy position. A routine disinfection of the external genitalia and vagina is performed, followed by placement of sterile drapes. A bimanual examination is conducted to assess the position and size of the uterus.
The vaginal speculum is inserted to expose the cervix, and the vaginal fornix and cervix are disinfected again. The anterior lip of the cervix is clamped with a cervical tenaculum. A cervical catheter is inserted along the direction of the uterine cavity and tightly fitted against the external cervical os.
The Y-shaped tube connects the cervical catheter to the pressure gauge and syringe. The pressure gauge is maintained at a level higher than the Y-shaped tube to prevent fluid from entering the gauge.
The syringe is filled with saline or antibiotic solution to ensure the catheter is free of air. The solution is then gradually injected into the uterine cavity, with pressure not exceeding 160 mmHg. Observations are made regarding the level of resistance during injection, the presence of fluid reflux, and whether the patient experiences abdominal pain.
Once the procedure is complete, the catheter is removed, and the cervix and vagina are disinfected again. The vaginal speculum is removed.
Result Interpretation
Patent Fallopian Tubes
If 20 mL of saline is injected smoothly without resistance, with a pressure below 60–80 mmHg, or if initial resistance resolves with continued injection and there is no reflux or discomfort reported by the patient, it indicates patent fallopian tubes.
Obstructed Fallopian Tubes
If resistance is noted with an injection volume of less than 5 mL, with significant discomfort or abdominal pain as pressure increases, and fluid refluxes back into the syringe after injection stops, this suggests fallopian tube obstruction.
Partially Patent Fallopian Tubes
Resistance during injection, which resolves upon increased pressure and allows fluid to pass, suggests the presence of mild adhesions that have been separated. This may be accompanied by mild abdominal pain reported by the patient.
Precautions
The temperature of the injected solution should be close to body temperature to avoid triggering tubal spasms due to cold fluid.
The cervical catheter should maintain a tight seal with the external cervical os during fluid injection to prevent leakage and ensure sufficient injection pressure.
Tub bathing and sexual intercourse should be avoided for at least two weeks after the procedure. Antibiotics may be prescribed as needed to prevent infection.
Hysterosalpingography
Hysterosalpingography includes conventional hysterosalpingography (HSG) and hysterosalpingo-contrast sonography (HyCoSy), both of which are used to evaluate the patency of the fallopian tubes, with a sensitivity of up to 94%. The former involves the injection of a contrast agent into the uterine cavity and fallopian tubes through a catheter, followed by X-ray fluoroscopy and imaging to determine tubal patency, the location of obstruction, and the morphology of the uterine cavity. The latter provides real-time visualization of contrast agent flow and distribution under ultrasound, offering clearer imaging, non-invasive and radiation-free characteristics, and easier execution.
Indications
These include:
- Clinical diagnosis of infertility.
- Assessment of fallopian tube patency, morphology, and the location of obstruction.
- Evaluation of the uterine cavity, including examination of the cervical internal os for laxity, identification of uterine anomalies and their types, as well as endometrial adhesions, submucosal fibroids, endometrial polyps, or foreign bodies.
- Pre-treatment evaluation before assisted reproductive techniques.
Contraindications
These include:
- Acute or subacute inflammation of internal or external genital organs.
- Severe systemic diseases.
- Pregnancy or menstruation.
- Within six weeks postpartum, following abortion, or after curettage.
- Allergy to iodine.
- Unresolved hyperthyroidism.
Pre-Procedure Preparation
The procedure is ideally performed 3–7 days after menstruation ends, with sexual activity avoided for three days prior.
Preoperative examinations include routine vaginal discharge tests, blood or urine human chorionic gonadotropin (hCG) tests, and gynecological ultrasound imaging. Iodine sensitivity testing is required; only patients with negative results may undergo iodinated oil-based hysterosalpingography.
Intramuscular injection of 0.5 mg atropine is administered 30 minutes prior to the procedure to relieve spasms.
A cleared bladder is required before the procedure. Patients with severe constipation may undergo preoperative enema to normalize uterine positioning and avoid false impressions caused by external pressure.
Procedure
Equipment and Instruments
The equipment may include an X-ray radiology unit or ultrasound machine (preferably three-dimensional color Doppler ultrasound), uterine catheter or Foley catheter (size 14), vaginal speculum, cervical tenaculum, gynecological forceps, and a 20 mL syringe.
Contrast Agents
Contrast agents are classified into oil-based and water-soluble iodine-based solutions. Oil-based agents offer high-density, stable, and clear imaging of the uterus and fallopian tube contours. Water-soluble agents are absorbed quickly and provide shorter procedural times but may present less detailed imaging of uterine and tubal margins, making small lesions harder to detect.
For hysterosalpingo-contrast sonography, ultrasound microbubble contrast agents are used due to their favorable imaging performance, minimal and transient adverse reactions, and rare allergic responses.
Steps
The patient is placed in the bladder lithotomy position. External genitalia and the vagina are routinely disinfected, sterile drapes are applied, and a bimanual exam clarifies the uterus's position and size.
A vaginal speculum is inserted, followed by further disinfection of the vagina and cervix. The anterior lip of the cervix is clamped with a cervical tenaculum, and the uterine cavity is explored.
For iodinated oil-based hysterosalpingography, a catheter is filled with 40% iodized oil contrast, air is removed, and the catheter is inserted into the cervical canal in the direction of the uterine cavity. The iodized oil is gradually injected while X-ray fluoroscopy is used to observe its flow through the fallopian tubes and uterine cavity, and images are captured. An X-ray is taken 24 hours later to assess the presence of free iodized oil in the pelvis.
For sonographic hysterosalpingography, a Foley catheter (size 14) is positioned in the uterine cavity, and 1–2 mL of saline is injected into the balloon to block the cervical internal os. Ultrasound microbubble contrast is gradually injected as a real-time ultrasound machine (preferably three-dimensional) monitors the imaging, patient reactions, and any reflux of the contrast agent.
When rounded uterine cornu and absent tubal imaging are observed after contrast injection, tubal spasm is suspected. Retaining the original setup and administering 0.5 mg atropine intramuscularly, followed by fluoroscopy and imaging 20 minutes later, may resolve the spasm. Alternatively, anti-spasmolytic agents may be used prior to a repeat study.
Result Evaluation
Normal Uterus and Fallopian Tubes
In conventional hysterosalpingography, the uterine cavity appears as an inverted triangle, with both fallopian tubes clearly outlined and free contrast agent scattered throughout the pelvis 24 hours later.
In sonographic hysterosalpingography, real-time visualization shows the contrast agent filling the uterine cavity and flowing through both fallopian tubes, surrounding the corresponding ovaries.
Abnormal Uterine Cavity
In endometrial tuberculosis, the uterine cavity loses its inverted triangular shape and presents with an irregular, serrated endometrial lining.
In the case of submucosal fibroids, an intraluminal filling defect is visible within the uterine cavity.
Uterine anomalies appear in accordance with their respective morphological presentations.
Fallopian Tube Abnormalities
Tubal tuberculosis demonstrates irregular and beaded appearances of the fallopian tubes, sometimes showing calcified foci.
Hydrosalpinx is characterized by balloon-like dilation of the distal fallopian tube.
Tubal abnormalities related to development may present as excessive length, shortening, aplasia, dilation, or diverticula.
In conventional hysterosalpingography, the absence of scattered contrast in the pelvis 24 hours after the procedure indicates tubal obstruction. In sonographic hysterosalpingography, the absence of contrast agent flow through both fallopian tubes or into the pelvis also suggests obstruction.
Precautions
Efforts should ensure no air remains in the catheter prior to insertion to prevent intrauterine air pockets that could result in filling defects and diagnostic errors.
Prevention of contrast leakage into the vagina is necessary to avoid overlapping artifacts that may distort imaging.
Over-insertion of the uterine catheter should be avoided to minimize the risk of uterine injury or perforation.
Excessive pressure or injection speed during contrast administration should be avoided to prevent tubal injury.
If contrast is observed entering abnormal channels under fluoroscopy, the procedure should be halted. If the patient develops a cough, an oil embolism should be suspected, requiring urgent intervention, including placing the patient in the Trendelenburg position and close monitoring.
Vaginal baths and sexual activity are typically avoided for two weeks after the procedure. Antibiotics may be prescribed to prevent infection.
Tubal obstruction may sometimes result from spasms, and repeat imaging may be necessary for confirmation.
Gynecological Endoscopic Examination of Tubal Patency
Techniques include laparoscopic direct visualization of tubal hydrotubation, hysteroscopic catheterization and hydrotubation of the tubal ostia, and combined hysteroscopic-laparoscopic examinations. Laparoscopic hydrotubation has an accuracy of 90%–95% and is considered the "gold standard" for assessing tubal patency. However, given its invasive nature, it is not recommended for routine use and is generally reserved as a second-line confirmatory test following hysterosalpingography in cases of confirmed obstruction. Laparoscopic hydrotubation may also be considered in patients undergoing concurrent laparoscopic surgery.