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Clinical trial on the methodology of hysterosalpingography: a comparative study Optimization of Hysterosalpingography Techniques

This comparative study of 251 infertile patients undergoing hysterosalpingography concludes that while premedication equalizes pain across methods, the metal cannula technique yields superior image quality and avoids the application difficulties and costs associated with balloon catheters.

Original authors: Gulseren Polat, Tugba Akcaoglu, Burak Yucel, Aysun Firat

Published 2026-07-30

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CC BY 4.0

Original authors: Gulseren Polat, Tugba Akcaoglu, Burak Yucel, Aysun Firat

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine you are trying to map the secret tunnels inside a castle. In the world of human reproduction, this castle is the uterus, and the tunnels are the fallopian tubes. For decades, doctors have used a special "X-ray paint" called contrast dye to see if these tunnels are open or blocked. This procedure is called Hysterosalpingography, or HSG for short. It's a bit like blowing bubbles into a pipe to see if they come out the other end, but instead of bubbles, they use a liquid that shows up bright white on an X-ray.

The problem is, this process can be quite uncomfortable. To get the paint to stay inside the castle and not leak out the front door (the cervix), doctors usually have to hold the door open with a metal clamp called a tenaculum. It's like trying to take a photo of a wiggly cat while holding its tail; the struggle often causes pain. Over the years, inventors have tried to make this easier. Some suggested using a tiny balloon to plug the door instead of a metal clamp, hoping it would be gentler and less painful. But does a balloon really make the ride smoother, or does it just get in the way of the view? This is the mystery a team of researchers at Istanbul Medipol University set out to solve.

The researchers decided to put three different "door-plugging" methods to the test on 251 women who were looking to have babies. They split the women into three groups: one group got the traditional metal cannula (a thin metal tube), a second group got an "active" balloon that the doctor inflates, and a third group got a "passive" balloon that expands on its own. To keep things fair, every woman took a pain-relief suppository an hour before the procedure, and the same doctor performed every single scan.

Here is what they found when they compared the three methods. First, the time it took to do the procedure was roughly the same for everyone, though the metal cannula was slightly faster to set up. However, the metal cannula group needed significantly more of that X-ray paint to get the job done. Why? The balloons acted like better seals, stopping the paint from leaking out, so less was needed.

When it came to pain, the results were a bit surprising. If you asked the women to rate their pain on a scale (the VAS score) right after the procedure, the numbers were almost identical across all three groups. Everyone felt a little bit of discomfort, and the most painful moment for everyone was when the paint was spreading through the tubes and into the belly, not when the door was being held open. However, when the doctor watched the women's faces and listened to their groans during the procedure, a difference appeared. The women with the metal cannula seemed to be in more pain than those with the balloons. The passive balloon group seemed to have the easiest time of all.

But here is the twist: while the balloons might have been slightly more comfortable for the patients, they were not the best for the doctor trying to take the picture. The metal cannula group produced the clearest, sharpest images. The doctors could see the edges of the uterus and the narrowest part of the tunnel (the isthmus) much better with the metal tube. The balloons, especially the active ones, sometimes got in the way or made it hard to see the bottom part of the uterus clearly. Also, the balloons were a bit finicky; in a few cases, they were too hard to place because of the angle of the uterus, or they slipped out, forcing the doctor to switch to the metal clamp anyway.

So, what is the final verdict? The study suggests that if a patient is given pain medication beforehand, the difference in pain between using a metal tube or a balloon isn't huge. The balloons do save money on the X-ray paint and might be slightly less uncomfortable for some, but they come with a high price tag for the equipment and can make the X-ray pictures fuzzy or incomplete. The metal cannula, despite being the "old school" method, still wins the prize for giving the doctor the best possible view of the castle's tunnels. The researchers conclude that while balloons are an interesting option, the metal cannula remains the champion for getting the clearest picture, and future studies should focus on finding even better ways to keep patients comfortable while using this reliable tool.

Technical Summary: Optimization of Hysterosalpingography Techniques

Problem Statement
Hysterosalpingography (HSG) remains the gold standard for evaluating uterine cavity anomalies and fallopian tube patency in female infertility, despite the emergence of alternative imaging modalities like HyCoSy and MR-HSG. While HSG is reliable and low-cost, it is associated with significant patient discomfort and pain. The primary sources of pain include cervical traction (often requiring a tenaculum), uterine distension during contrast injection, and peritoneal irritation from contrast leakage. Various techniques have been proposed to mitigate this, including the use of balloon catheters (active and passive) versus the traditional metal cannula, often with the goal of eliminating the need for a tenaculum and reducing contrast leakage. However, existing literature has largely focused on patient pain scores, with limited discussion regarding how these different methodologies impact the clinician's ability to interpret image quality, particularly regarding uterine margins and the isthmus.

Methodology
This single-blind clinical trial, registered as the "MethodHSG Study" (NCT07583758), compared three distinct HSG techniques in 251 infertile patients (aged 18–45) undergoing the procedure during the follicular phase. The study was conducted at Istanbul Medipol University and Basaksehir Cam and Sakura City Hospital between January 2020 and August 2022.

Study Groups:
- Group 1 (Metal Cannula): $n=158$ .
- Group 2 (Active Balloon Catheter): $n=50$ .
- Group 3 (Passive Balloon Catheter): $n=43$ .
Standardization: All procedures were performed by a single experienced gynecologist (GP) to eliminate operator variability. A second clinician (AF) independently interpreted the images. All patients received premedication with a 100 mg indomethacin suppository one hour prior to the procedure to manage pain.
Procedure: Patients were educated 15 minutes prior to the scan. The study utilized a water-soluble radiopaque contrast agent (Urografin).
Exclusion Criteria: Patients with conditions affecting pain thresholds (e.g., endometriosis, chronic pelvic pain, depression, diabetes) were excluded.
Metrics: The study evaluated procedural time, volume of contrast agent used, pain scores (Visual Analog Scale [VAS] and clinician-observed behavioral scores), procedural failure rates, and image quality assessment (uterine margins, cavity, isthmus, and tubal patency).

Key Results

Procedural Efficiency: There was no statistically significant difference in total procedural time between groups ( $p=0.207$ ). However, the metal cannula group had the shortest average application time (25 seconds) compared to the active (30 seconds) and passive (33 seconds) balloon groups.
Contrast Usage: The metal cannula group required a significantly higher volume of contrast agent ( $p<0.001$ ). The balloon groups required less contrast, attributed to the balloon preventing backflow into the vagina.
Pain Assessment:
- Post-procedure VAS: No significant difference was found in VAS scores immediately after the procedure or 30 minutes later among the three groups.
- Intra-procedural Observation: The gynecologist observed significantly higher pain behaviors (verbal and physical) in the metal cannula group compared to the passive balloon group ( $p=0.023$ ).
- Pain Phases: For all groups, the most painful phase was the distribution of the contrast agent into the peritoneum, not the initial cervical traction.
Image Quality and Interpretation:
- The metal cannula group yielded the highest total imaging scores.
- Uterine Margins & Cavity: Assessed with high accuracy in the metal cannula group (86.7% and 85.4%, respectively).
- Uterine Isthmus: This was the most differentiating factor. The metal cannula group achieved the best assessment (75.9%), while the active balloon group performed the worst (33.3%) due to the balloon obstructing the view.
- Tubal Patency: All three methods assessed fallopian tube patency with equal accuracy.
Complications and Failures: The balloon groups experienced a 4.3% procedural failure rate due to difficulties in placement (e.g., excessive uterine anteversion preventing visualization) or balloon displacement. The metal cannula group had zero procedural failures.

Key Contributions

Comparative Image Quality Analysis: Unlike previous studies focusing solely on pain, this paper provides a direct comparison of how instrumentation affects the diagnostic clarity of specific anatomical regions, specifically highlighting the metal cannula's superiority in visualizing the uterine isthmus.
Premedication Context: The study demonstrates that when patients are premedicated with NSAIDs, the pain differences between traction methods (tenaculum vs. balloon) are minimized, challenging the assumption that balloon catheters are inherently less painful in a premedicated population.
Technical Trade-offs: The research quantifies the trade-off between contrast conservation (favoring balloons) and image quality/procedural reliability (favoring metal cannulas).

Significance and Claims
The authors conclude that while balloon catheter techniques offer advantages in reducing contrast agent usage and fluoroscopy time, they present significant disadvantages in clinical practice. These include difficulty in application due to uterine position, higher costs associated with single-use devices, and, most critically, the negative impact of the balloon's location on image quality, particularly obscuring the uterine isthmus.

The paper asserts that the metal cannula method provides the best image quality for clinician interpretation, offering the clearest visualization of uterine margins, the cavity, and the isthmus. Furthermore, in premedicated patients, the metal cannula method does not result in significantly higher pain scores compared to balloon techniques when evaluated by standard VAS, though clinician-observed behavioral pain was slightly higher. The study suggests that future efforts to improve patient satisfaction should focus on optimizing analgesic protocols for the metal cannula method rather than switching to balloon techniques that compromise diagnostic image quality.

Technical Summary: Optimization of Hysterosalpingography Techniques

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