What is chronic pelvic pain?
Long-term recurrent lower abdominal pain, also known as chronic pelvic pain, refers to non-cyclical pelvic pain that lasts for more than 6 months (also considered to be more than 3 months) and is ineffective for non-opioid medication. Pain is one of the most common symptoms in women, and there are acute and chronic symptoms, both due to lesions or injuries in the pelvic organs, with an acute onset, typical presentation, and no difficulty in diagnosis, and usually cured in a short time. Chronic pelvic pain (CPP) is characterized by a complex etiology, and sometimes no obvious cause can be found even after laparoscopy or open exploration, and the degree of pain is not necessarily proportional to the degree of lesion. In contrast, psychogenic chronic pelvic pain should be considered as a somatic symptom caused by psychological factors and is often diagnosed clinically as functional chronic pelvic pain, which is called psychological (or psychiatric) chronic pelvic pain according to the theory of the modern biopsychosocial-psychological medical model.
What are the causes of chronic pelvic pain?
Visceral pain refers to the pain sensation caused by internal organs such as the bowel, bladder, rectum, uterus, ovaries and fallopian tubes, as opposed to somatic pain, which refers to the skin, fascia and muscles such as the external genitalia, anus, urethra and mural peritoneum. Unlike somatic pain, visceral pain is difficult to localize and usually presents in a cutting, crushing or burning pattern, although it manifests as somatic pain but usually not in the affected visceral area. Clinical studies have proven that the causes that can cause visceral pain are.
1. dilatation or abnormal contraction of cavernous visceral muscles such as uterine contractions during childbirth;
2. sudden pulling of the envelope of a solid viscus such as a ruptured hemorrhagic ovarian cyst;
3. Hypoxia or necrosis of the viscera, such as adnexal torsion or uterine fibroid degeneration;
4, secretion of pain-causing substances such as dysmenorrhea and prostaglandins in endometriosis;
5, chemical stimulation of visceral peripheral nerves such as rupture of cystic teratoma with spillage of oily contents;
6.Sudden compression of ligaments or blood vessels ;
7, inflammation, such as adnexitis.
In addition, the sensitivity of the viscera to pain varies greatly, with the lowest pain threshold in the plasma membrane, followed by the muscle, and the highest in the substantive organs. The external genitalia contain rich somatic nerves, which are very sensitive to pain, and pain is easily localized.
Why does it hurt?
The sensory innervation of the pelvic organs is derived from the autonomic trunk, whose cytomes of sympathetic fibers are distributed in the thoracic and lumbar medullary spinal cord, while the cytomes of parasympathetic fibers are in the sacral dorsal ganglion, both of which are involved in visceral sensory and neural reflexes in the visceral afferent nervous system. The main pelvic organ pain sensory nerve in women is the sympathetic nerve. The sensory innervation of a specific pelvic organ depends on its embryonic origin. From an embryological developmental point of view, the reproductive organs can be divided into 3 categories, namely, the gonads from the urogenital crest, the uterus, ovaries, fallopian tubes and upper vagina from the malleolus and the lower vagina and vulva from the urogenital sinuses. The innervation of the female pelvic organs and somatic structures is shown in Figure 2. The lower abdominal wall and the anterior part of the vulva, including the clitoris and urethra, are innervated by a mixture of somatic nerves (sensory and motor nerves) from the ventral branch of the 1st to 2nd lumbar spinal cord segment. The dorsal branch nerves originate from lumbar 1 to 2 and innervate the lumbosacral region, which is usually the reflex pain area for gynecological pain. The perineum, anus, and lower vaginal segment are innervated by the somatic branch of the pubic nerve, which originates from the 2nd to 4th sacral nerve roots. Painful stimuli from the superior vaginal segment, cervix, uterine body, medial part of the fallopian tube, broad ligament, upper bladder, appendix, appendix and terminal colon are transmitted to the sympathetic nerves of the thoracic and lumbar medulla, the vaginal, uterine and inferior abdominal plexus to the inferior abdominal nerve, then through the inferior epigastric plexus to the sympathetic trunk of the lumbar medulla and lower thoracic medulla, and the nerve impulses converge with the thoracic 11-12 and lumbar 1 through the white branch then through the dorsal roots of these nerves to the thoracic 11-12 and lumbar 1 spinal cord through the dorsal roots of these nerves.
Nerve impulses from the upper vagina, cervix, and lower uterus were previously thought to enter sacral 2-4 via the parasympathetic nerves of the pelvic nerve, but this is still controversial. The first stage of labor is a process of cervical dilation, stretching and tearing, and Bonica’s study of nerve block anesthesia for pain relief in all phases of labor suggests that although pain reflexes to sacral 2-4 dermatomes in the early stages of labor, pain transmission in the 1st stage of labor is through the uterine plexus, the lower inferior abdominal plexus to the hypogastric nerve, and then through the lower epigastric plexus to the lumbosacral and lower thoracic medullary sympathetic trunks, as previously described. The visceral reflex pain that occurs in the lumbosacral region is modulated by the cortical branches of the lower thoracic and upper lumbar medullary nerves, which are distributed in the lower lumbar and sacral regions. When the second stage of labor is almost over and the pain is mainly from stretching, pulling and tearing of the perineum, a block of the pubic nerve (somatic sacral nerve) can eliminate the pain.
However, considering the embryologic origin, at least part of the vagina is derived from the urogenital sinuses, as well as the bladder and rectum. Therefore, the afferent nerves of the vagina may enter the sacral medulla in addition to the thoracolumbar medulla mentioned above. This has been confirmed by pelvic neurectomy experiments in rats. Thus, it seems that the afferent nerves of the thoracolumbar and sacral medulla are doubly innervated. The afferent nerve from the ovary travels with the ovarian artery from the sympathetic ganglion of the 4th lumbar vertebra into the sympathetic trunk, which then travels up the sympathetic trunk and enters the spinal cord at the level of the thoracic 9-10. The innervation of the outer 2/3 of the fallopian tube and the upper ureter is similar to that of the ovary. Neither the inferior epigastric plexus nor the inferior mesenteric plexus contains afferent nerves to the ovaries and lateral fallopian tubes, which may explain why clinical resection of the sacral nerve (inferior epigastric plexus) can only relieve pain in the middle of the pelvis (uterus) but not eliminate pain of adnexal (ovarian) origin. Therefore, the transmission of painful stimuli in the pelvic organs depends on an intact sympathetic innervation system. Moreover, an intact afferent and efferent system of the sacral nerves is essential for the normal function of the genital organs, colon and bladder.
Pelvic nerve resection affects normal urinary and defecation functions, but if only the sympathetic nerves of the pelvis are removed, i.e., without affecting bowel, bladder and reproductive functions, there is no serious effect on visceral sensation in the bowel and bladder. The nerve structure described above makes the sensory neurons the first of many signal relay stations, thereby transmitting signals of pain sensation in the pelvic organs to the brain. The cell of the afferent nerve axon is located in the sensory (dorsal) root ganglion of the spinal nerve. The axons bifurcate and merge into the spinal cord, where they terminate into superior and inferior branches that extend into the spinal cord above and below the segment, respectively. Many of these superior and inferior branches become part of the Lissaure Tract, the dorsolateral tract, which is located at the dorsal border of the gray matter of the spinal cord. Depending on the appearance of the gray matter of the spinal cord and the density of neurons, the dorsal horn of the gray matter of the spinal cord forms neural plates, which are arranged sequentially from the dorsal to the central neural plate. Starting from the bundle of Lissauer, the afferent axons of the visceral nerves enter the gray matter of the spinal cord through the 1st, 5th to 8th, and 10th nerve plates in the dorsal horn, while the innervated nerves of the trunk enter the gray matter of the spinal cord through the 2nd to 4th nerve plates.
How to treat chronic pelvic pain?
Traditional Chinese medicine treatment
Some patients are suffering from cold stagnation and qi stagnation, so the treatment is to warm the menstruation and disperse cold, move qi and activate blood. Commonly used is Gui Zhi Fu Ling Tang with addition and subtraction. For Qi deficiency, add 15g of Radix Codonopsis Pilosulae, 9g of Atractylodes Macrocephala and 15g of Radix Astragali.
Western medicine treatment methods
Drug treatment.
Surgical treatment.
Psychotherapy.
Biofeedback therapy.
Studies have shown that patients with chronic prostatitis have a synergistic dysfunction of the pelvic floor muscles or tension in the external urethral sphincter. Biofeedback combined with electrical stimulation therapy can relax and harmonize the pelvic floor muscles and relax the external sphincter, thus relieving the perineal discomfort and urinary symptoms of chronic prostatitis.