Erectile dysfunction (ED), also called impotence, is the type of sexual dysfunction in which the penis fails to become or stay erect during sexual activity. It is the most common sexual problem in men. Through its connection to self-image and to problems in sexual relationships, erectile dysfunction can cause psychological harm. In about 80% of cases, physical causes can be identified. These include cardiovascular disease; diabetes mellitus; neurological problems, such as those following prostatectomy; hypogonadism; and drug side effects. About 10% of cases are psychological impotence, caused by thoughts or feelings; here, there is a strong response to placebo treatment. The term erectile dysfunction is not used for other disorders of erection, such as priapism. Treatment involves addressing the underlying causes, lifestyle modifications, and addressing psychosocial problems. In many cases, treatment is attempted by drugs, specifically PDE5 inhibitors (such as sildenafil), which dilate blood vessels, allowing more blood to flow through the spongy tissue of the penis (akin to opening a valve further in order to allow more water to enter a fire hose). Other treatments, less commonly used, include prostaglandin pellets, inserted in the urethra; smooth-muscle relaxants and vasodilators, injected into the penis; penile implants; penis pumps; and vascular reconstructive surgery. Signs and symptoms
ED is characterized by the regular or repeated inability to achieve or maintain an erection of sufficient rigidity to accomplish sexual activity. It is defined as the "persistent or recurrent inability to achieve and maintain a penile erection of sufficient rigidity to permit satisfactory sexual activity for at least 3 months."
Arachnoiditis is an inflammatory condition of the arachnoid mater or arachnoid, one of the membranes known as meninges that surround and protect the nerves of the central nervous system, including the brain and spinal cord. The arachnoid can become inflamed because of adverse reactions to chemicals, infection from bacteria or viruses, as the result of direct injury to the spine, chronic compression of spinal nerves, complications from spinal surgery or other invasive spinal procedures, or the accidental intrathecal injection of steroids intended for the epidural space. Inflammation can sometimes lead to the formation of scar tissue and adhesion that can make the spinal nerves "stick" together, a condition where such tissue develops in and between the leptomeninges. The condition is extremely painful, especially when progressing to adhesive arachnoiditis. Another form of the condition is arachnoiditis ossificans, in which the arachnoid becomes ossified, or turns to bone, and is thought to be a late-stage complication of the adhesive form of arachnoiditis. Signs and symptoms
Arachnoid inflammation can lead to many painful and debilitating symptoms which can vary  greatly in each case, and not all people experience all symptoms. Chronic pain is common, including neuralgia, while numbness and tingling of the extremities can occur with spinal cord involvement, and bowel, bladder, and sexual functioning can be affected if the lower part of the spinal cord is involved. While arachnoiditis has no consistent pattern of symptoms, it frequently affects the nerves that supply the legs and lower back.