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Background: The Codman-Hakim Programmable Valve is widely used in shunting hydrocephalus and other conditions., Object: To establish an accurate valve verification system for the Codman-Hakim programmable valve that does not require radiographic exposure., Methods: Prospective clinical trial tested a new valve verification system at 9 research sites., Results: The Valve Programming and Verification System allowed us to establish the valve setting in 62% of subjects with a programmable valve., Conclusion: The Valve Programming and Verification System avoids radiation exposure, is cost-effective, and time efficient for the patient and provider. In approximately one third of subjects, those in whom "adjustment complete" is not achieved, cranial radiographs are still needed.

Objective: This retrospective study examined whether changes in ventricular volume correspond with changes in adjustable valve pressure settings in a cohort of patients who received shunts to treat idiopathic normal pressure hydrocephalus. We also examined whether these pressure-volume curves and other patient variables would co-occur with a positive clinical response to shunting., Methods: We selected 51 patients diagnosed with idiopathic normal pressure hydrocephalus who had undergone implantation of a Codman Hakim programmable valve (Medos S.A., Le Locle, Switzerland). Clinical data were gathered from the patients' records and clinical notes by an investigator blinded to patients' ventricular volumes. Ventricular volume was measured using 3D Slicer, an image analysis and interactive visualization software package developed and maintained at the Surgical Planning Laboratory at Brigham and Women's Hospital., Results: Eighty-six percent of patients with gait disturbance at presentation showed improvement of this symptom, 70% experienced improvement in incontinence, and 69% experienced improvement in dementia. For the group showing 100% clinical improvement, the correlation coefficient of average changes in valve pressure over time (delta P/delta T) and average changes in ventricular volume over time (delta V/delta T) were high at 0.843 (P < 0.05). For the group experiencing no or only partial improvement, the correlation coefficient was 0.257 (P = 0.32), indicating no correlation between average delta V/delta T and average delta P/delta T for each patient., Conclusion: This was a carefully analyzed modeling study of idiopathic normal pressure hydrocephalus treatment made possible only by adjustable valve technology. With careful volumetric analysis, we found that changes in ventricular volume correlated with adjustments in valve pressure settings for those patients who improved clinically after shunting. This suggests that positive clinical responders retained parenchymal elasticity, emphasizing the importance of dynamic changes in this cohort.

Cerebrospinal fluid shunting is an important method of treating hydrocephalus. It sometimes has been difficult to achieve the optimum CSF pressure and ventricular size after shunt placement. Hydraulic and mechanical mismatching may occur, creating either overdrainage, as manifested by slit ventricle syndrome and/or subdural hygromas; or underdrainage, as manifested by a failure of the ventricles to change in size, with persistence of symptoms. A variable pressure valve (Codman-Medos Programmable Hakim valve system) has been developed to allow non-invasive increase or decrease in cerebrospinal fluid pressure in differentials of 10 mm of water within a range of 30-200 mm of water. This allows the neurosurgeon to adjust the pressure to the patient's particular clinical needs at any given moment. As part of a pilot study of the valve's safety, 13 patients in this center were treated with this programmable shunting system from October 1991 to January 1993. Twelve patients were over age 18 and one was younger than this. Six patients had previously been shunted with other valve systems, and the remaining seven had never been shunted before. The etiology of hydrocephalus included idiopathic normal pressure hydrocephalus (6 patients), aqueductal stenosis (3 patients), Chiari malformation (2 patients), meningitis (1 patient), and unknown etiology (1 patient). This paper describes the use of this valve in five illustrative cases; slit ventricle syndrome in an adult, chronic ventriculomegaly with aqueductal stenosis (2 cases), and idiopathic normal pressure hydrocephalus (2 cases). This programmable valve has been particularly useful in gradually decreasing ventricle size in idiopathic normal pressure hydrocephalus.(ABSTRACT TRUNCATED AT 250 WORDS)