1. Anatomy and therapeutic basis: The fallopian tubes, one on each side of the uterus, are a pair of long, thin, curved tubes. The fallopian tubes start from the uterine horn, their lumen is connected to the uterine cavity at the proximal end and opens in the abdominal cavity at the distal end, the inner side is connected to the uterine horn and the outer end is free, while close to the ovaries, with a total length of 8-14 cm. According to its morphology, the fallopian tube can be divided into four parts: the interstitial part (or uterine part), the isthmus, the abdomen, and the umbrella (funnel part). The free end of the tube is funnel-shaped and has many whisker-like tissues, which have the function of “egg collection”. The fallopian tubes are the fertile channel for transporting eggs and facilitating the union of eggs and sperm, and if blocked, pregnancy is impossible. The main causes of tubal lesions are tubal inflammation, pelvic peritonitis, untreated vaginitis, cervicitis, endometritis, pelvic inflammatory disease, sexually transmitted diseases, etc. Inflammation of the fallopian tubes from various causes can destroy the mucous membrane of the tubes, form scarring and adhesions, and narrow or block the tubal lumen. The purpose of treatment is to eliminate or control the inflammation, unblock the fallopian tubes, and allow the infertility patient to get pregnant as soon as possible. 2. Non-interventional techniques and radio-interventional techniques General lavage is the most common treatment method in clinical practice. It is performed 2-3 days after menstruation and before ovulation. 20ml of physiological saline with chymotrypsin, antibiotics and dexamethasone is injected into the uterine cavity through a catheter. This method is simple and easy for the patient to accept, but it is easy to cause infection in the uterine cavity and aggravate the patient’s condition, and the injection is blind, and it is not known whether it can enter the fallopian tube. With the application of endoscopic technology in obstetrics and gynecology, the treatment of tubal obstruction is safer and more effective, and the blindness of general lavage is reduced, such as lavage through the hysteroscopic tubal opening or lavage of the tubal interstitium or tubal lumen under the guidance of abdominal ultrasound and laparoscopy has been gradually applied in clinical practice. Microsurgical treatment This method is an emerging treatment for tubal infertility in recent years. The surgical methods include adhesion separation, tubalplasty and tubal recanalization, which have achieved good results in clinical practice. According to Liang’s report, the efficacy of microscopic techniques in the treatment of tubal obstruction infertility is positive. However, there are still some patients who have little chance of pregnancy even if their tubes are reopened after surgery. This is due to the fact that the postoperative residual tubes are lower than the preoperative length, the long duration of preoperative infertility, hydrosalpinx, thinning of the tube wall, and the loss of ciliated cells in the lumen of the tubes, etc. According to Frantzen et al, pregnancy is no longer possible when the loss of ciliated cells in the lumen of the tubes reaches more than 75%. Factors affecting the success of intubation: In addition to improving the technical level of the operation and selecting a suitable catheter according to the morphology of the uterine cavity, it is important to understand the endocrine status of the patient’s menstrual cycle, menstrual period, menstrual volume and endometrial condition before the operation. In the study data of Li Qunying et al, 11 cases were aborted due to contrast reversal into the blood vessels during the operation, among which 5 patients were found to have low menstrual flow and short menstrual period of only 2-3 days, and the operation was chosen to be performed on the 4th and 5th day after menstrual cleansing. Due to the poor growth or thinness of the endometrium, the procedure was aborted because the catheter easily touched the submucosa during the operation and damaged the blood vessels. For such cases, preoperative history should be taken and the operation should be postponed (also before ovulation). Ultrasound is also available to detect the thickness of the endometrium, usually above 5mm. Factors affecting the rate of tubal recanalization The rate of tubal recanalization is directly related to the nature of the tubal lesion, the site of obstruction, the degree of tubal wall lesion and the adhesions at the umbilical end. It is very important to take a detailed history, read the HSG film carefully, master the surgical indications and make good preoperative preparation and pre-operative evaluation before surgery. (1) Indications and contraindications for SSG Indications: ① Normal uterine cavity with unrevealed or partially revealed HSG tubes; ② Incomplete tubal obstruction treated with intubation and lavage. Contraindications: (1) definite tubal tuberculosis; (2) hydrosalpinx; (3) nodular tubal infection or formation of more diverticula or sinus tracts in the wall of the fallopian tube; (4) obvious adhesions at the end of the umbilicus or formation of peri-implantation. (2) Indications and contraindications for FTR Indications: Clear obstruction of the interstitial and isthmus segments of the fallopian tubes. Contraindications: ① obstruction of the isthmus with pestle-like changes at the end; ② obstruction of the abdomen and umbilicus of the fallopian tube; ③ obstruction of the anastomosis after tubal anastomosis; ④ fibrosis of the fallopian tube.