Safe intrauterine adhesion prevention support and use method thereof
By using a hollowed-out spiral pear-shaped hydrogel scaffold, combined with ultrasound measurement and physiological peristalsis design, the problems of difficult operation, pressure control and timing of existing anti-intrauterine adhesion scaffolds have been solved, achieving safe and effective intrauterine isolation and endometrial repair.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANYANG CITY CENT HOSPITAL
- Filing Date
- 2026-04-10
- Publication Date
- 2026-05-12
AI Technical Summary
Existing anti-intrauterine adhesion stents have problems such as difficult operation, improper pressure control, and inappropriate timing, which can lead to secondary damage, infection risk, and recurrence of adhesions.
Using a hollowed-out spiral-shaped pear-shaped hydrogel scaffold, the individual uterine size is measured by ultrasound, and the scaffold is expanded to fit the uterine wall with a pressure of less than 10 mmHg. The scaffold contains drug components, which are broken up and expelled with physiological peristalsis, achieving continuous drug delivery and safe withdrawal.
It achieves safe and effective intrauterine isolation and endometrial repair, avoids secondary damage and infection risks, reduces the recurrence rate of adhesions, and adapts to individual differences and menstrual cycles.
Smart Images
Figure CN122005159A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of medical technology, specifically relating to a safe stent for preventing intrauterine adhesions and its method of use. Background Technology
[0002] Under normal physiological conditions, the endometrium is intact, with a complete basal layer structure and normal function. Although the anterior and posterior walls of the uterine cavity are in contact with each other, they do not adhere. Even if the endometrium suffers minor trauma, it will quickly regenerate and repair the wound due to its cyclical shedding function, preventing adhesions.
[0003] However, common intrauterine procedures, surgeries, and inflammation can damage the basal layer of the endometrium, leading to thinning or defects in the endometrium. During wound repair, inflammatory exudation and cell proliferation can cause granulation tissue and collagen deposition, gradually developing into intrauterine adhesions. Intrauterine adhesions (IUA), also known as Asherman's syndrome, are often caused by intrauterine procedures such as induced abortion and curettage, or inflammation leading to damage to the basal layer of the endometrium, resulting in partial or complete closure of the uterine cavity. Clinical manifestations include decreased menstrual flow, amenorrhea, and infertility. In assisted reproductive technologies, endometrial adhesions affect the success rate of in vitro fertilization-embryo transfer.
[0004] Although numerous methods and techniques exist for treating intrauterine adhesions, a completely effective way to avoid them entirely still lacks a universally accepted treatment standard. Currently, common treatment methods include medication and instruments.
[0005] The drug-based approach involves injecting medications, such as hyaluronic acid, chitosan, estrogen, progesterone, or polylactic acid gel, into the uterine cavity to achieve treatment. If the medication is solid, it is difficult to completely cover the uterine cavity wall, thus affecting its anti-adhesion effect. If the medication is liquid, it is prone to thrombosis, and the medication has a short residence time in the uterine cavity, resulting in poor long-term efficacy. If the medication is in gel form, it may cause significant swelling and deformation, which is detrimental to the tension-free repair of soft tissues.
[0006] Instrumental methods primarily rely on mechanical barriers for isolation, such as balloon stents, intrauterine devices (IUDs), double-lumen catheters, and anti-adhesion membranes. While balloon stents effectively provide hemostasis and act as a mechanical barrier, excessive pressure can lead to endometrial ischemia and impair endometrial repair, while insufficient pressure can cause them to detach and lose their effectiveness. Even specially designed Cook balloon stents may have limited effectiveness due to short placement times, failing to prevent new adhesions and leading to postoperative re-adhesion. However, prolonged placement increases the risk of inflammation and infection. Furthermore, friction caused by uterine contractions can cause mechanical damage leading to aseptic inflammation or balloon entrapment. Anti-adhesion membranes form a continuous gel-like protective film on the surface of the uterine cavity, providing an effective barrier for a relatively long time. However, they become abrasive when wet, making them difficult to pass through the uterine canal and difficult to unfold spontaneously within the uterine cavity, resulting in exposed areas without anti-adhesion membrane coverage.
[0007] Patent CN102120059A discloses a drug-eluting membrane stent for preventing intrauterine adhesions. It uses a basket woven from nickel-titanium alloy wire with shape memory properties as a support to adhere a thin film material coated with a slow-release drug layer to the uterine cavity wall, thus preventing intrauterine adhesions. However, it requires retrieval after treatment, which may cause damage due to mechanical separation, hindering endometrial repair.
[0008] Patent CN103417272A discloses a drug-eluting uterine stent that uses a balloon for support and squeezes liquid or gel-like medication through small pores in the stent into the endometrium, thereby achieving a synergistic effect between the medication and the stent. However, it still suffers from the problems of the balloon and stent themselves, as well as the fact that the liquid or gel-like medication only works for a short period of time.
[0009] Patent CN115607746A discloses a self-expanding intrauterine anti-adhesion repair device and its application. This device uses a self-expanding intrauterine anti-adhesion repair device where the inner core membrane gradually expands during the absorption of exudate, stretching the outer micro-nano fiber membrane to adhere to the uterine wall, forming a protective membrane to repair the endometrium. However, the absorption time of this repair device is uncertain, making it impossible to determine the effective start time of repair. Furthermore, the absence of a menstrual outflow tract is detrimental to the recovery of the menstrual cycle, thus affecting the pregnancy outcome of assisted reproductive technology.
[0010] Patent CN107744417A discloses a fully degradable intrauterine postoperative anti-adhesion device, which is prepared using a fully degradable polymer scaffold and drug coating. It does not require surgical removal after implantation and poses no risk of infection from transvaginal invasion. However, its shape and pressure are not adjustable, making it difficult to adapt to different uterine shapes and suitable physiological environments conducive to endometrial recovery.
[0011] Patent CN119215236A discloses a self-healing hydrogel for preventing intrauterine adhesions, its preparation method, and its application. The self-healing hydrogel can be applied to the special structure of the uterine cavity, anchoring itself to uterine wounds and creating favorable conditions for long-term endometrial repair. Without pressure, the uterus cannot expand, thus isolating the endometrium. During uterine contractions, adhesions are easily formed, preventing it from achieving its intended effect.
[0012] The patent with publication number CN223350399U proposes an absorbable biological scaffold to prevent intrauterine adhesions. It uses a certain degree of elasticity to stretch the uterine wall. It can be directly absorbed by the patient without disassembly, which improves safety. However, the pressure between the scaffold and the uterine wall cannot be controlled.
[0013] The patent with publication number CN117903458A proposes a method for preparing a hydrogel for preventing intrauterine adhesions. By introducing dopamine groups, it increases the hydrogel's ability to adhere to the endometrium, prolongs the retention time of stem cells, enhances the vitality and secretory activity of stem cells in the hydrogel, promotes endometrial regeneration and improves fertility, but does not address the safety concerns associated with the device.
[0014] Patent CN219742838U discloses a device for preventing intrauterine adhesions. It primarily utilizes a shape-memory support frame that repositions itself within the uterine cavity upon body temperature, causing the isolation balloon to expand and the isolation membrane to adhere to the two uterine horns. The isolation membrane exerts minimal pressure on the uterine wall, and intrauterine fluid can flow out through the gap between the isolation membrane and the uterine wall, reducing the risk of intrauterine infection. The device is also activated by pulling on a tail string, which can be removed from the loop.
[0015] Patent CN118892585A discloses a uterine cavity anti-adhesion gel, its preparation method, and its application. The method involves injecting a soft hydrogel into the uterine cavity using a syringe. After moderate cross-linking, the gel adheres to the inner surface of the uterine cavity, adapting to the cavity shape without causing pressure or other damage. Furthermore, the hydrogel gradually transforms into a fluid aqueous solution and is expelled from the body within 4-7 days. However, a problem exists: excessive pressure leads to leakage, while insufficient pressure prevents the uterine cavity from expanding.
[0016] The patent with publication number CN114404789A proposes an automatically pressure-controlled, self-releasing balloon dilatation uterine stent. It uses a constant-pressure pusher to inject water into the balloon to prevent excessive compression of the uterus and reduce the risk of endometrial damage. However, the safety pressure is achieved through an external pusher, which increases the risk of infection.
[0017] The patent with publication number CN120267904A proposes an endometrial repair scaffold and its preparation method. It utilizes the fluidity of hydrogel to fill the uterine cavity and places a nanofiber composite membrane at the wound site. The cross-linking of hydrogel and nanofiber increases the firmness, enabling the repair membrane to be reshaped in vivo according to the shape of the uterus. The shear thinning effect is used to ensure its injectability. However, it is difficult to control the amount of hydrogel added. Too little hydrogel will result in insufficient pressure, while too much hydrogel will result in excessive pressure and the risk of overflow.
[0018] In summary, current patents cannot effectively control the pressure between the stent and the uterine wall (e.g., CN102120059A, CN103417272A, CN107744417A, CN115607746A, CN117903458A, CN118892585A, CN119215236A, CN120267904A, CN219742838U, CN223350399U) or control the pressure through external pressure (e.g., CN114404789A). Non-degradable stents require secondary removal, posing a risk of secondary injury and infection. Degradable stents suffer from mismatched support performance and degradation cycles, leading to displacement and collapse, and failing to achieve complete isolation throughout the uterine cavity. Drug delivery systems often lack precise, phased release, resulting in low drug utilization. Furthermore, they generally lack proper drainage design, easily leading to secondary infections from intrauterine hematoma and fluid accumulation, and cannot adapt to the rhythmic physiological contractions of the uterine cavity, easily causing endometrial pressure damage. These methods fail to fundamentally address the core issues of post-operative adhesion re-adhesion and endometrial repair after intrauterine adhesion surgery. Additionally, the lack of consideration for women's independent menstrual cycles increases the risk of infection. Summary of the Invention
[0019] The purpose of this invention is to provide a safe anti-intrauterine adhesion stent and its method of use, solving the following problems of existing anti-adhesion stents:
[0020] (1) The operation is relatively difficult and may cause new damage, such as difficulty in passing through the cervix, and difficulty in unfolding after entering the uterus and may cause uterine incarceration.
[0021] (2) It is difficult to achieve appropriate pressure. For example, excessive pressure is not conducive to the recovery of the endometrium and can cause endometrial ischemia, while insufficient pressure can easily cause the uterus to slip out.
[0022] (3) It is difficult to choose a suitable effective time. For example, if the time is too short, the endometrial tissue will not be able to recover well and secondary adhesions are likely to occur. If the time is too long, it will not be conducive to the shedding of the endometrium and the discharge of menstrual blood and will easily cause infection.
[0023] The technical solution of this invention is:
[0024] A safe anti-intrauterine adhesion stent, characterized in that it is composed of hydrogel and sterile water for injection, wherein: the hydrogel has a hollowed-out spiral inverted pear-shaped structure, with its maximum external dimensions being length l = 2~3 mm, top width w1 = 1~2 mm, bottom width w2 = 0.1~0.5 mm, thickness t = 0.5~1 mm, and volume v; the hydrogel is prepared from non-degradable materials or degradable materials with a degradation period of more than 1 month, and expands to equilibrium upon contact with sterile water for injection to form a stent, the stent having dimensions of 7~9 cm in length, 4~5 cm in width, and 2~3 cm in thickness, its shape matching the uterine cavity and completely conforming to the inner wall of the uterine cavity, with the top and bottom of the stent abutting against the top and bottom of the uterus, respectively; the amount of sterile water for injection is calculated according to the formula V = min(L / l, W / w1, T / t) × v, where L is the actual length of the patient's uterus measured by ultrasound, W is the actual top width of the patient's uterus measured by ultrasound, and T is the actual thickness of the patient's uterus measured by ultrasound.
[0025] The aforementioned safe anti-intrauterine adhesion stent exerts a pressure on the endometrium of no more than 10 mmHg, the maximum equilibrium expansion ratio of the hydrogel after contact with water is 100 to 1000 times, the compressive strength of the hydrogel after expansion is 16 mmHg to 26 mmHg, and the time required for the hydrogel to reach equilibrium after expansion upon contact with water is no more than 4 hours.
[0026] The aforementioned safe anti-intrauterine adhesion stent exerts a pressure of 3-5 mmHg on the endometrium, has a maximum equilibrium expansion ratio of 200-500 times after the hydrogel comes into contact with water, a compressive strength of 16-20 mmHg after expansion, and takes 1-3 hours for the hydrogel to reach equilibrium after expansion.
[0027] The aforementioned safe anti-intrauterine adhesion stent has a uniform helical spacing, or a denser helix at the bottom and a looser helix at the top; the helix diameter is uniform, or a thicker helix at the bottom and a thinner helix at the top.
[0028] The aforementioned safe anti-intrauterine adhesion stent has a spherical head.
[0029] The aforementioned safe anti-intrauterine adhesion stent contains one or more of the following in its hydrogel: endometrial isolation substance, endometrial regeneration drug, and antibiotic drug.
[0030] The aforementioned safe anti-intrauterine adhesion stent uses one or more of the following endometrial isolation substances: hyaluronic acid, chitosan, and polylactic acid; the endometrial regeneration drug is estrogen and progesterone; and the antibiotic is penicillin.
[0031] The aforementioned safe anti-intrauterine adhesion stent allows for continuous drug delivery by gradually exuding the added components in the hydrogel over time, and achieves potent drug delivery by releasing a large amount of the components when the stent breaks due to physiological peristalsis of the uterus.
[0032] A safe method for using a stent to prevent intrauterine adhesions includes the following steps:
[0033] (1) The actual length L, actual top width W, and actual thickness T of the uterus in patients with intrauterine adhesions were measured by ultrasound.
[0034] (2) Soak the hydrogel in sterile water for injection for 1 minute, then remove it and place it in the patient's uterus, with the top of the hydrogel at the top of the uterus;
[0035] (3) Calculate the amount of sterile water for injection according to the formula V=min(L / l,W / w1,T / t)×v and inject it into the patient's uterus;
[0036] (4) Adjust the patient to a supine position;
[0037] (5) 10-30 minutes after injecting sterile water for injection, the placement of the stent is determined by ultrasound, and the stent that has begun to expand is adjusted according to the ultrasound results.
[0038] (6) The patient can get out of bed and resume activities 4 hours after the injection of sterile water for injection;
[0039] (7) When the patient has her first menstrual period or when the uterus contracts, the stent breaks under the pressure of the physiological peristalsis of the uterus and is expelled from the body with the menstrual blood.
[0040] In the method of using the safe anti-intrauterine adhesion stent, in step (2), the hydrogel is placed in the patient's uterus using a delivery system or surgical instrument ring removal forceps.
[0041] The design concept of this invention is:
[0042] The stent of this invention is small in size before implantation and can safely pass through the cervix. Subsequently, after the stent expands inside the uterus, it opens the uterine cavity with controllable minimal pressure to prevent intrauterine adhesions, thus preventing the endometrial recovery from being affected by pressure. At the same time, if the stent breaks under excessive pressure, it will not cause impingement or affect the discharge of menstrual blood, thus achieving safe and effective prevention and treatment of intrauterine adhesions.
[0043] (1) First, measure the actual size of the patient's uterus by ultrasound, and then use this size to calculate how much sterile water for injection needs to be added so that the small-sized hydrogel expands in the uterus into a support that fits the uterus perfectly. It will not be too small to open up and prevent adhesions, nor will it put too much pressure on the endometrium.
[0044] (2) The force of the stent in the uterus is very gentle and will not cause ischemia of the endometrium or affect repair. When the uterus contracts normally (such as during menstruation), the force generated can break the stent into small particles. It can be removed without surgery and discharged with the menstrual blood, avoiding long-term inflammation and getting stuck.
[0045] (3) The stent itself is made of hydrogel material. The unexpanded hydrogel is very small and can be easily inserted into the uterus through the cervix without damaging the cervix and endometrium, and it is not easy to get stuck in the uterus.
[0046] (4) The stent contains anti-adhesion, endometrial repair and anti-infection drugs. It will slowly seep out and continuously treat the uterus. When the uterus contracts and the stent breaks, the drugs will be released in large quantities at once, which is just at the critical time of endometrial shedding and repair, so that the treatment is more effective.
[0047] In summary, this invention, based on the natural physiological structure and peristaltic rhythm of the human uterus and the actual needs of endometrial repair, effectively isolates the uterine cavity and assists in endometrial repair without interfering with or damaging its normal physiological functions. Through gentle and safe support and close-fitting repair drug delivery, the stent serves only as a temporary aid during the uterine repair phase. After completing the protective repair, it is automatically expelled with the natural physiological activities of the uterus, fundamentally reducing the recurrence of intrauterine adhesions after surgery and promoting the complete repair of the endometrial structure and function.
[0048] The advantages and beneficial effects of this invention are as follows:
[0049] 1. The initial stent of this invention is small in size, with the hydrogel being only millimeters in size before implantation. After soaking in sterile water for injection, the surface friction is reduced, allowing it to pass smoothly through the narrow cervical opening without cervical dilation. This ensures safe passage through the cervix and avoids mechanical damage to the cervix and endometrium during implantation. At the same time, the spherical tip design further eliminates the risk of endometrial abrasion, solving the problems of difficult implantation and easy secondary damage caused by existing anti-adhesion membranes, alloy stents, and other instruments.
[0050] 2. This invention is based on the three-dimensional parameters of the uterine cavity measured by ultrasound of the patient. The amount of sterile water for injection is calculated by ultrasound measurement of the uterine size. This allows for the expansion of a safe and effective stent that adapts to the patient's actual size. The stent will not be too small to effectively expand the endometrium, nor will it be too large to damage the endometrium. The expanded stent perfectly matches the shape and size of the patient's uterine cavity, ensuring effective isolation of the entire uterine cavity with no blind spots for anti-adhesion, while also preventing the endometrium from being damaged due to excessive size. This solves the problems of existing stents being unable to adapt to individual differences in the uterus, being prone to detachment, or easily damaging the endometrium.
[0051] 3. Because the size of the stent of this invention closely matches the size of the uterus, the pressure exerted by the stent on the endometrium is low, generally less than 10 mmHg, preferably 3~5 mmHg. This allows the endometrium to recover under its normal physiological conditions, fundamentally solving the dilemma of existing balloon stents that are prone to ischemia due to high pressure and prone to detachment due to low pressure. This achieves a balance between preventing adhesions and promoting repair.
[0052] 4. The safe anti-adhesion stent of this invention maintains a stable support structure during the critical period of endometrial repair. Its compressive strength is 16mmHg~26mmHg, preferably 16mmHg~20mmHg. It will break during the physiological peristalsis of the uterus without affecting the physiological peristalsis of the uterus, especially menstruation, and can be discharged from the body with menstruation, without the need for secondary surgical retrieval, thus avoiding secondary damage during the retrieval operation. At the same time, the breaking and discharge of the stent is completely adapted to the patient's physiological cycle, does not hinder the discharge of menstrual blood, and completely avoids the risks of intrauterine infection, inflammation, and incarceration caused by long-term indwelling.
[0053] 5. The safe anti-adhesion stent of this invention is made of hydrogel material, which has a smooth surface and good compatibility with endometrial tissue, making it difficult for uterine incarceration to occur. Even if uterine incarceration occurs, due to its low compressive strength, it can be locally broken to eliminate the uterine incarceration phenomenon. Its safety is far higher than that of various existing rigid stents and balloon stents.
[0054] 6. The safe anti-adhesion stent of this invention contains effective drug components that can improve the recovery environment of the endometrium, enabling continuous drug administration throughout the entire treatment cycle and accelerating the recovery of the endometrium. Especially during critical periods such as menstruation, a large amount of drug can be released as the stent breaks down, maximizing the anti-adhesion, repair-promoting, and infection-preventing effects of the drug. This is beneficial for effectively improving the recovery environment of the endometrium during endometrial shedding and further reducing the incidence of postoperative re-adhesion. Attached Figure Description
[0055] Figure 1 Schematic diagram of a hydrogel scaffold in the uterus. In the diagram, 1 is the scaffold, and 2 is the uterus.
[0056] Figure 2A schematic diagram of a safe anti-intrauterine adhesion stent from different angles, showing a hollow, slightly flattened, spiral-shaped inverted pear-shaped structure.
[0057] Figure 3 Compression curve of a certain hydrogel scaffold, where the compressive strength is around 18 mmHg.
[0058] Figure 4 The sustained-release effect of the hydrogel scaffold structure containing drugs and other components under its diffusion mechanism (A), and the rapid release effect after fragmentation, especially when fragmented near the drug components (B). In the figure, 1 is the scaffold, and 2 is the uterus. Detailed Implementation
[0059] like Figures 1-2 As shown, this invention proposes a safe anti-intrauterine adhesion stent, composed of hydrogel and sterile water for injection. The hydrogel has a hollowed-out spiral-shaped inverted pear-shaped structure. The stent 1, formed by the hydrogel expanding upon contact with water, matches the shape of the uterine cavity 2 and completely conforms to the inner wall of the uterine cavity. The top and bottom of the stent 1 abut against the top and bottom of the uterine cavity 2, respectively. The hollowed-out spiral structure effectively isolates the anterior and posterior walls of the uterine cavity while reserving physiological space within the uterine cavity, preventing uterine cavity blockage and endometrial compression. This structure allows for safe stent placement in patients with intrauterine adhesions, providing appropriate pressure support after placement and intelligently completing effective treatment in accordance with the physiological movement of the endometrium.
[0060] The requirements for the hydrogel are as follows: the maximum external dimensions of the hydrogel are length l = 2~3 mm, top width w1 = 1~2 mm, bottom width w2 = 0.1~0.5 mm, and thickness t = 0.5~1 mm; the volume v (mL) of the hydrogel depends on the material and structure of the hydrogel; the material of the hydrogel is a non-degradable material or a degradable material with a degradation period of more than 1 month. The hydrogel expands after the addition of sterile water for injection and reaches equilibrium within 4 hours to form an anti-intrauterine adhesion scaffold. The scaffold dimensions are length L = 7~9 cm, width W = 4~5 cm, and thickness T = 2~3 cm, and it matches the uterine cavity. The amount of sterile water for injection added is calculated based on the uterine volume measured by ultrasound or other methods, thus obtaining an anti-intrauterine adhesion scaffold suitable for the patient. The pressure of the anti-intrauterine adhesion scaffold on the endometrium should not exceed 10 mmHg, preferably 3~5 mmHg. The prepared anti-intrauterine adhesion scaffold will break when subjected to a pressure greater than 16 mmHg.
[0061] like Figure 2As shown, the hydrogel has a hollow structure similar to the uterus or a slightly flattened inverted pear shape. When it swells upon contact with water, it forms a scaffold, specifically as follows: the base of the scaffold is slightly larger and the top is slightly smaller, conforming to the shape of the uterus; the spiral spacing of the scaffold can be uniform, or slightly denser at the bottom and slightly looser at the top, increasing the support at the bottom; the spiral diameter of the scaffold can be uniform, or slightly thicker at the bottom and slightly thinner at the top, increasing the support at the bottom; the head of the scaffold is a spherical structure without sharp edges, which can avoid damage to the endometrial tissue.
[0062] The maximum equilibrium expansion ratio of the hydrogel after contact with water is 100 to 1000 times, preferably 200 to 500 times; the compressive strength of the hydrogel after expansion of 100 to 1000 times is 16 mmHg to 26 mmHg, preferably 16 mmHg to 20 mmHg. Examples of some samples are shown below. Figure 3 As shown in the figure, the compression curve of the hydrogel scaffold clearly shows that the compressive strength of the scaffold gradually increases with the increase of compressive strain. When the compressive strength reaches about 18 mmHg, the curve shows a clear inflection point, indicating that the scaffold has reached the critical compressive strength and is about to break. The time required for the hydrogel to reach equilibrium after swelling upon contact with water is no more than 4 hours, preferably 1 to 3 hours.
[0063] like Figure 4 As shown, the hydrogel may contain substances that benefit endometrial isolation, such as hyaluronic acid, chitosan, and polylactic acid; drugs that promote endometrial regeneration, such as estrogen and progesterone; or antibiotics such as penicillin. These components gradually seep out of the stent over time, achieving a continuous drug delivery effect and providing sustained treatment. These components are released in large quantities when the stent breaks due to strong uterine peristalsis, providing a potent therapeutic effect. Among them, (A) is a schematic diagram of the slow diffusion and release effect of drugs when the stent is intact. The diagram shows that functional components (endometrial isolation substances, regenerative drugs, antibiotics, etc.) are uniformly dispersed in the hydrogel stent. These components slowly seep out from the interior of the hydrogel matrix into the uterine cavity through molecular diffusion, without a large-scale concentrated release, reflecting the process of continuous release of functional components over time, demonstrating the technical effect of the stent in providing long-term continuous treatment in the uterine cavity. (B) is a schematic diagram of the rapid and large-scale drug release effect after the stent breaks due to the physiological peristalsis of the uterus. The diagram shows that after the stent breaks, the functional components originally wrapped inside the hydrogel matrix are fully released along with the stent. Especially in the areas where the drug components are rich, there is a clear phenomenon of concentrated drug release and diffusion after the stent breaks. The drug release rate and release amount are much higher than the sustained release state in (A), reflecting the process of strong burst release of functional components when the stent breaks. This demonstrates the technical effect of the stent in exerting a strong therapeutic effect during the critical period of endometrial repair (menstruation, uterine contraction).
[0064] like Figures 1-4As shown, this invention proposes a safe method for using a stent to prevent intrauterine adhesions, comprising the following steps:
[0065] (1) Measure the uterine dimensions of patients with intrauterine adhesions by ultrasound, such as length L (mm), top width W (mm), and thickness T (mm);
[0066] (2) After soaking the hydrogel in sterile water for injection for 1 minute, remove it and place it in the uterus, with the top of the hydrogel at the top of the uterus: ① Place it in the uterus through a delivery system; ② Place it in the uterus through conventional surgical instruments such as ring forceps.
[0067] (3) Prepare the amount of sterile water for injection as V(mL) = min(L / l, W / w1, T / t)×v and inject it into the uterus; in the above calculation formula, V represents the total amount of sterile water for injection to be injected into the uterus (mL), L represents the actual length of the patient's uterus measured by ultrasound (mm); l represents the length of the hydrogel itself before implantation (mm); W represents the actual top width of the patient's uterus measured by ultrasound (mm); w1 represents the top width of the hydrogel itself before implantation; T represents the actual thickness of the patient's uterus measured by ultrasound (mm); t represents the thickness of the hydrogel itself before implantation (mm); v represents the volume of the hydrogel before implantation (mL).
[0068] Assume the ultrasound measurements of the patient's uterus are: L = 80 mm (length), W = 45 mm (top width), T = 25 mm (thickness); and the pre-implantation hydrogel parameters are: l = 2.5 mm (length), w1 = 1.5 mm (top width), t = 0.8 mm (thickness), v = 0.002 mL (hydrogel volume). First, calculate the three expansion ratios using the above formulas: L / l = 80 / 2.5 = 32; W / w1 = 45 / 1.5 = 30; T / t = 25 / 0.8 = 31.25. Then, take the minimum expansion ratio: min(32, 30, 31.25) = 30. Finally, calculate the total volume of sterile water for injection required to be injected into the uterus: V = 30 × 0.002 = 0.06 mL.
[0069] Because each patient's stent is obtained through ultrasound measurement and formula calculation, the drawbacks of existing fixed-size stents are eliminated. Numerically, it ensures that the size of the expanded hydrogel fits the uterus 1:1, which not only effectively expands the uterine cavity and isolates and prevents adhesions, but also fundamentally avoids endometrial compression and ischemic damage caused by excessively large stents.
[0070] (4) Adjust the patient with intrauterine adhesions to a supine position and relieve the patient's intrauterine adhesions;
[0071] (5) At 10-30 minutes, preferably 20 minutes, the placement of the stent in patients with intrauterine adhesions is determined by ultrasound. If a delivery system is used to place the hydrogel, this examination can be omitted. If conventional surgical instruments such as ring forceps are used to place the hydrogel, the hydrogel stent, which has begun to expand at this time, needs to be adjusted appropriately according to the ultrasound measurement results.
[0072] (6) The patient can get out of bed and recover after 4 hours;
[0073] (7) The first menstrual period or when the uterus contracts can cause the anti-adhesion stent to break and be expelled from the body.
[0074] The results show that the stent of the present invention is based on the physiological structure and movement of the uterus. It is composed of hydrogel with therapeutic effects. After passing through the cervix, it absorbs water and expands to stretch the inner wall of the uterus. The physiological pressure generated by the peristalsis of the endometrium causes the stent to break into small particles and be expelled from the body with menstrual blood. This effectively prevents adhesions in the uterine cavity without causing uterine infection or excessive pressure. It is not affected by the individual size of the uterus or the menstrual cycle, thus improving its safety.
Claims
1. A safe stent for preventing intrauterine adhesions, characterized in that, It is composed of hydrogel and sterile water for injection. The hydrogel has a hollow, spiral-shaped inverted pear-shaped structure with a maximum external dimension of length l = 2-3 mm, top width w1 = 1-2 mm, bottom width w2 = 0.1-0.5 mm, and thickness t = 0.5-1 mm, and a volume of v. The hydrogel is prepared from non-degradable materials or degradable materials with a degradation period of more than one month. After being exposed to sterile water for injection, it expands to equilibrium to form a scaffold. The scaffold has a length of 7-9 cm, a width of 4-5 cm, and a thickness of 2-3 cm. Its shape matches the uterine cavity and completely conforms to the inner wall of the uterine cavity. The top and bottom of the scaffold abut against the top and bottom of the uterus, respectively. The amount of sterile water for injection is calculated according to the formula V = min(L / l, W / w1, T / t) × v, where L is the actual length of the patient's uterus measured by ultrasound, W is the actual top width of the patient's uterus measured by ultrasound, and T is the actual thickness of the patient's uterus measured by ultrasound.
2. The safe anti-intrauterine adhesion stent according to claim 1, characterized in that, The pressure of the stent on the endometrium is no more than 10 mmHg. The maximum equilibrium expansion ratio of the hydrogel after contact with water is 100 to 1000 times. The compressive strength of the hydrogel after expansion is 16 mmHg to 26 mmHg. The time required for the hydrogel to reach equilibrium after expansion when it comes into contact with water is no more than 4 hours.
3. The safe anti-intrauterine adhesion stent according to claim 2, characterized in that, The pressure of the stent on the endometrium is 3~5 mmHg, the maximum equilibrium expansion ratio of the hydrogel after contact with water is 200~500 times, the compressive strength of the hydrogel after expansion is 16mmHg~20mmHg, and the time required for the hydrogel to reach equilibrium after expansion with water is 1~3 hours.
4. The safe anti-intrauterine adhesion stent according to claim 1, characterized in that, The helical spacing of the support is set uniformly, or dense at the bottom and loose at the top; the helical diameter of the support is set uniformly, or thick at the bottom and thin at the top.
5. The safe anti-intrauterine adhesion stent according to claim 1, characterized in that, The head end of the support has a spherical structure.
6. The safe anti-intrauterine adhesion stent according to claim 1, characterized in that, The hydrogel contains one or more of the following: endometrial isolation substances, endometrial regeneration drugs, and antibiotics.
7. The safe anti-intrauterine adhesion stent according to claim 6, characterized in that, The endometrial barrier material is one or more of hyaluronic acid, chitosan, and polylactic acid; the endometrial regeneration drug is estrogen and progesterone; and the antibiotic is penicillin.
8. The safe anti-intrauterine adhesion stent according to claim 7, characterized in that, The added components in the hydrogel gradually seep out of the stent over time to achieve continuous drug delivery, and release a large amount of drug when the stent breaks due to physiological peristalsis of the uterus to achieve potent drug delivery.
9. A method of using a safe anti-intrauterine adhesion stent as described in any one of claims 1 to 8, characterized in that, Includes the following steps: (1) The actual length L, actual top width W, and actual thickness T of the uterus in patients with intrauterine adhesions were measured by ultrasound. (2) Soak the hydrogel in sterile water for injection for 1 minute, then remove it and place it in the patient's uterus, with the top of the hydrogel at the top of the uterus; (3) Calculate the amount of sterile water for injection according to the formula V=min(L / l,W / w1,T / t)×v and inject it into the patient's uterus; (4) Adjust the patient to a supine position; (5) 10-30 minutes after injecting sterile water for injection, the placement of the stent is determined by ultrasound, and the stent that has begun to expand is adjusted according to the ultrasound results. (6) The patient can get out of bed and resume activities 4 hours after the injection of sterile water for injection; (7) When the patient has her first menstrual period or when the uterus contracts, the stent breaks under the pressure of the physiological peristalsis of the uterus and is expelled from the body with the menstrual blood.
10. The method of using the safe anti-intrauterine adhesion stent according to claim 9, characterized in that, In step (2), the hydrogel is placed in the patient's uterus using a delivery system or surgical instrument ring retrieval forceps.