1. Why does a herniated lumbar disc have difficulty in urinating and defecating? When the herniated disc compresses and stimulates the cauda equina nerve, numbness near the perineum and anus occurs. When the central disc herniation is huge and protrudes from the posterior median into the spinal canal, compressing the cauda equina nerve below the plane of the herniation, constipation, uncontrolled defecation, urinary retention, filling incontinence, and sexual dysfunction such as impotence and occasionally persistent penile erection will occur. These manifestations are clinically known as cauda equina syndrome. 2, how can intermittent claudication occur in lumbar disc herniation? Intermittent claudication is the main manifestation of lumbar spinal stenosis. However, the herniated disc can also protrude into the spinal canal, making spinal stenosis or lumbar disc herniation complicated by spinal stenosis, in addition to back and leg pain also manifested as intermittent claudication, that is, walking for a period of time will appear lower limb pain and numbness aggravated, squatting or sitting down to rest for a moment and can walk a distance again. 3, is a lumbar disc herniation why the lower extremity radiating pain site is different? This is caused by compression of a nerve root of the sciatic or femoral nerve when the disc is herniated. Since the disc herniation occurs mostly on one side, it creates unilateral femoral nerve or sciatic nerve pain. Radicular pain mostly starts in the buttocks and gradually radiates downward, but to which part of the body it radiates depends on the site of the herniation. (1) Interlumbosacral herniation, radiating through the posterior thigh and N fossa to the posterior calf, metatarsal and little toe; (2) Interlumbar 4-5 herniation, radiating through the posterior outer thigh, through the N fossa to the lateral calf ending at the dorsal bunion of the foot; (3) Interlumbar 3-4 herniation, radiating through the anterior thigh, downward to the anterior inner calf, to the anterior inner dorsal foot. However, herniated lumbar 4-5 can have radiating pain of lumbosacral herniation; lumbar 3-4 or lumbar 2-3 can also have symptoms of lumbar 4-5 and lumbosacral herniation, depending on whether the location of the herniation is very outward or slightly centered. 4.What is the nature of neuralgia of lumbar disc herniation? The nature of neuralgia includes numbness, tingling and swelling, etc. Generally, numbness is the most common. The pain can be aggravated by coughing and sneezing because these actions temporarily cause the veins in the spinal canal to dilate, the pressure in the spinal canal to increase, and the pressure in the arachnoid membrane to increase the compression of the herniated material on the nerve root. Because of the large pressure on the intervertebral disc when standing, the bulge is also large, and the pressure on the nerve is heavy. Therefore, walking or standing can also aggravate the pain. 5. How can lumbar pain become leg pain? Many patients with lumbar disc herniation have lower extremity neuralgia, and then the lumbar pain can be relieved immediately. This is because the pressure on the dura or posterior longitudinal ligament is reduced by the bulging fibrous ring, and the nerve fibers are stimulated less, while the compression of the herniated material is mainly concentrated on the nerve roots, so the back pain becomes leg pain. In addition, it is also possible that the leg pain with nerve root compression is heavier than the lumbar pain, thus masking the lumbar pain, which is due to the heavier nerve pain that produces reflex inhibition through the cerebral cortex. 6.Why is low back and leg pain sometimes light and sometimes heavy? Low back pain and leg pain can be continuous or intermittent. But clinically, as long as there has been low back pain and radiation to the legs, even if the symptoms disappear at some point, the possibility of recurrence of disc herniation cannot be ruled out. The pain will persist as long as the compression and inflammatory irritation are not relieved, but it may also be mild and severe at times. If the patient’s pain is aggravated by the protrusion of the herniation due to heavy workload or more lumbar activities, which increases the pressure on the nerve root, sometimes the local inflammation is reduced after rest, and thus the pain is reduced or disappears; sometimes the relationship between the nerve root and the position of the protrusion is occasionally changed after activity, i.e., the protrusion is displaced, which can also reduce the pain.