Management of patients with normal pressure hydrocephalus by using lumboperitoneal shunt system with the Codman Hakim programmable valve: 6 years of clinical experience

Fifty-seven patients with normal-pressure hydrocephalus (NPH) were managed using the lumboperitoneal (LP) shunt system in which the Codman Hakim programmable valve was utilized. Fifty-two of the fifty-seven patients (91.2%) improved after surgery, but five patients did not. The initial opening pressure was selected according to the patients' condition (mean pressure 62.81 nun H2O). In 30 patients (52.6% of the cases), the valve pressure adjustment was required at least once (mean number of adjustments 1.73, maximum 4). The final valve pressure was between 30 and 170 mm H2O (mean pressure 70.53 mm H2O). In this study, several patients required a wide range of pressure changes during the period of observation, in some as much as 120 mm H2O. Lumboperitoneal shuntography was performed in eight patients by injection of contrast medium into the prechamber. In three patients, shunt obstructions were found out. Shuntography using the radionuclide is useful to evaluate the patients with NPH, especially when the underdrainage of the shunt is suspected. Complications occurred in four patients. Transient low-pressure symptoms such as headache, headheaviness, nuchal pain and vomiting were observed in several patients but disappeared soon after increasing the valve pressure. Six patients developed a slight asymptomatic subdural effusion, which resolved after increasing the valve pressure. Wound infection was observed in one patient which seemed to be from belt friction over the Hakim valve.