Tubal occlusion is a method of permanent contraception that involves blocking or severing the fallopian tubes to prevent an egg from reaching the uterus and being fertilized by sperm. This procedure is commonly referred to as “getting your tubes tied.” Tubal clamps, such as the Filshie clip, are a widely used technique for achieving this result. The process is typically performed laparoscopically, a minimally invasive surgery involving small incisions, which provides immediate birth control by mechanically obstructing the pathway of the egg.
The Design and Function of Tubal Clamps
Tubal clamps are small, mechanical devices applied to the fallopian tube to create a physical and biological barrier. Historically, the two primary types were the Filshie clip and the Hulka clip, though the Filshie clip is currently the more widely accepted device. The Filshie clip is constructed from a titanium shell and features a silicone rubber lining on its inner surface.
The materials chosen for the Filshie clip—titanium and medical-grade silicone—are selected for their excellent biocompatibility, meaning they are non-toxic and do not degrade when permanently implanted. During the laparoscopic procedure, a specialized applicator delivers the clamp to the isthmic portion of the fallopian tube, the narrow segment closest to the uterus. Once applied, the hinged clip closes and latches, exerting continuous pressure across the entire diameter of the tube.
This constant pressure mechanism causes localized tissue death, or avascular necrosis, in the small segment of the tube enclosed by the clamp. As the tissue dies, the compressed silicone lining of the clip expands slightly to maintain complete occlusion of the tube’s lumen. This action effectively destroys approximately four millimeters of the tube, leading to the formation of scar tissue, or fibrosis, which permanently separates the two ends of the fallopian tube.
Lifetime Durability and Intended Permanence
Tubal clamps are specifically designed to provide permanent sterilization, built to last for the remainder of a person’s life without replacement or degradation. The titanium and silicone used in the Filshie clip are inert and non-magnetic, ensuring they are not subject to corrosion or material breakdown over decades. The clip itself is a permanent fixture and does not have a mechanical expiration date.
The longevity of the sterilization effect relies on both the material integrity of the clamp and the body’s biological response. The initial mechanical occlusion is quickly reinforced by the body’s healing process, which generates dense scar tissue around the compressed segment of the tube. This fibrosis forms a robust, natural block that maintains the tubal separation.
Concerns about the clamp breaking or wearing out over time are mitigated by its design and material composition. The titanium provides the structural strength necessary to withstand the body’s internal environment for a lifetime. Even if a clip shifts—a known, rare complication—the resulting scar tissue remains a primary barrier against fertilization, maintaining the long-term contraceptive effect. The clamps are engineered to be a singular, definitive procedure.
Comparing Clamp Failure Rates to Other Methods
While the material durability of the clamps is indefinite, the statistical efficacy of the procedure is measured by its long-term failure rate, or the risk of unintended pregnancy. Overall, tubal clamps compare favorably with many other forms of permanent contraception. The 10-year cumulative probability of failure for Filshie clips is estimated to be low, ranging from 4.1 to 23.3 pregnancies per 1,000 procedures.
Failure rates for other methods studied in the U.S. Collaborative Review of Sterilization (CREST) showed a wider 10-year cumulative failure range, from 7.5 to 36.5 pregnancies per 1,000 procedures, depending on the technique used. The Hulka clip, a less common device today, was found to have poorer efficacy and a significantly higher 10-year failure rate than the Filshie clip. Other techniques, like monopolar coagulation, also showed higher 10-year failure rates.
When failure occurs, it typically happens early in the post-operative period, not due to clip degradation decades later. Failures are often attributed to technical issues during application, such as incomplete occlusion of the tube. Another cause is the body creating a tiny channel, known as a fistula, that reconnects the two segments of the tube. If pregnancy occurs after sterilization, there is an elevated risk of ectopic pregnancy, where the fertilized egg implants outside the uterus.
Options for Reversal and Removal
Despite being intended as permanent, tubal clamping offers a higher potential for successful surgical reversal compared to more destructive sterilization methods. Tubal reversal, known as tubal reanastomosis, involves microsurgery to remove the damaged segment of the tube and stitch the healthy remaining ends back together. Since clamps destroy only a minimal portion of the fallopian tube (typically four millimeters), this often leaves a sufficient length of healthy tube for reattachment.
Success rates for pregnancy following reversal are influenced by factors like the patient’s age and the remaining healthy tubal length. However, success can reach a cumulative intrauterine pregnancy rate greater than 70% for women under 35 years old. The procedure is often performed using advanced laparoscopic or robotic techniques, which allow for the precise microsuturing required to restore tubal patency.
Simple removal of the clamps, without the goal of fertility restoration, is rare and generally considered only if medically necessary. This may be due to complications such as chronic pelvic pain or confirmed clip migration outside the fallopian tube. While the clamps are designed to be inert, surgical removal is an option for addressing these uncommon medical concerns.