This is usually inserted in the posterior fossa, but a shunt in the lateral ventricles may be used instead or in conjunction. Endoscopic third ventriculostomy (ETV) is a less invasive option for patients older than 1 year. Posterior fossa shunts are most effective (80% of the time) but carry the highest risk of complications, while ETV is least effective but has the least risk of complications. The mortality rate is roughly 15%, mostly due to complications from hydrocephalus or its treatment, which can include subdural haematomas or infection. The prognosis after successful hydrocephalus treatment is usually good but depends on any associated condition and its symptoms. Those without hydrocephalus are treated based on any associated symptoms or condition.The prevalence of DWM is estimated at between 1 in 25,000 to 1 in 50,000. DWM is the cause of around 4.3% of cases of congenital hydrocephalus and 2.5% of all cases of hydrocephalus. At least 21% of those with DWM have a sibling with the malformation, and at least 16% have a parent with the malformation. The malformation was first described by English surgeon John Bland-Sutton in 1887, though it was named by German psychiatrist Clemens Ernst Benda in 1954 after American neurosurgeons Walter Dandy and Arthur Earl Walker, who described it in 1914 and 1942, respectively. Signs and symptoms
Hydrocephalus
The most frequent and prominent symptoms of DWM are those associated with hydrocephalus in the postnatal period. Hydrocephalus occurs in an estimated 80% of patients with classic DWM.
Perineural catheters that provide local anesthetic agents have poor evidence of success when placed after surgery in an effort to prevent phantom limb pain.One approach that has received public interest is the use of a mirror box. The mirror box provides a reflection of the intact hand or limb that allows the patient to "move" the phantom limb, and to unclench it from potentially painful positions.Although mirror therapy was introduced by VS Ramachandran in the early 1990s, little research was done on it before 2009, and much of the subsequent research has been of poor quality, according to a 2016 review. A 2018 review, which also criticized the scientific quality of many reports on mirror therapy (MT), found 15 good-quality studies conducted between 2012 and 2017 (out of a pool of 115 publications), and concluded that "MT seems to be effective in relieving PLP, reducing the intensity and duration of daily pain episodes. It is a valid, simple, and inexpensive treatment for PLP." Other phantom sensations
Phantom sensations may also occur after the removal of body parts other than the limbs, e.g. after amputation of the breast, extraction of a tooth (phantom tooth pain) or removal of an eye (phantom eye syndrome).Some people who have undergone gender reassignment surgery have reported the sensation of phantom genitals. The reports were less common among post-operative transgender women, but did occur in transgender men. Similarly, subjects who had undergone mastectomy reported experiencing phantom breasts; these reports were substantially less common among post-operative transgender men.