The Importance of the Dual-Switch Valve for the Treatment of Adult Normotensive or Hypertensive Hydrocephalus

Abstract

Since the beginning of 1995 the new hydrostatic dual-switch valve (DSV) was implanted in 35 adult patients with hydrocephalus of different etiology. 26 patients suffered from normotensive hydrocephalus (10 idiopathic and 16 symptomatic), and 9 patients from hypertensive hydrocephalus of various origin. The first 21 cases of this cohort were compared in a randomized study with a comparable group of 21 hydrocephalic patients who received a conventional differential-pressure (DP-) valve. The clinical status and CT were assessed prior to shunting, 14 days and 3 and 6 months after the operation. The reduction of ventricular size was evaluated by the measurement of the Evans Index. The CT follow-up in the DSV group was characterized by an only minimal (14) or only slight (16) reduction of ventricular size in the vast majority of cases. A comparison of 21 patients with a DSV and the patients with DP valves, evaluated by measuring the reduction of the Evans Index, revealed a distinctly higher percentage of significant regressions in the DP valve collective, without doubt due to chronic overdrainage. The overall clinical result of our 35 patients with a DSV was excellent and good in 31 patients, but the outcome seems to be more dependent on the preshunt damage of the brain than on hydrocephalic aspects. A neglegible incidence of subdural effusions in the DSV group compared to 11 cases in the DP valve collective reflects the ability of the DSV to prevent overdrainage. The capability of the DSV to maintain the IVP within physiological limits after shunting, especially in the upright position, is documented by a comparison with possible unphysiological IVP variations in other valve constructions, which depend on the level of implantation, subcutaneous pressure or CSF flow through the valve.

Guidelines for Management of Idiopathic Normal Pressure Hydrocephalus: Second Edition

“…55) Furthermore, one study using an antisiphon device (the dual-switch valve) showed a 3% transient incidence of subdural hygroma and no cases needing operation. 56) In contrast, patency rates for Orbis-Sigma Valve } (Integra NeuroSciences, Sophia Antipolis, France) were lower than for the other tested valves and the rates of operation for subdural hematoma were higher than for the other valves. 66) Other reports of infrequent complications include gastrointestinal and bladder perforations from peritoneal catheters, 34) hearing deficits, 61) and tension pneumocephalus.…”

“…However, reports have shown that there are no major differences between the valves in terms of complication rates of infection 30,51,55,68) or shunt occlusion. 32,55,56,67) However, the use of antibiotics during the perioperative period has been shown to reduce the incidence of infection. 67) Complications of nontraumatic subdural hygroma/hematoma were reported to improve by resetting to higher pressures in the Codman-Hakim Programmable Valve } and Sophy Valve } , and evacuative operations were only required in 2.7% of cases using the Codman-Hakim Programmable Valve } 51,68) and 1.4% using the Sophy Valve } .…”

“…On the contrary, there are also conflicting reports indicating that the diameter of the midbrain does not change after shunt surgery Clinical Guidelines for iNPH, 2nd edition and does not correlate with the improvement of gait disturbance. 48,56) The diagnostic value of this finding is uncertain. In iNPH, the cross-sectional area of the corpus callosum on a mid-sagittal MRI section is small compared with healthy controls, and is increased after shunt surgery.…”

Guidelines for Management of Idiopathic Normal Pressure Hydrocephalus Guidelines From the Guidelines Committee of Idiopathic Normal Pressure Hydrocephalus, the Japanese Society of Normal Pressure Hydrocephalus

“…Although the use of antisiphon devices reportedly reduces the incidence of subdural effusion, complete prevention cannot be obtained. 107,108) Further, underdrainage of flow may occur. Whether these devices can be recommended for routine use in iNPH is still unsettled (Recommendation grade C).…”

“…133A) Patency rates of shunts at 1 year after operation have been reported to be 75% for CHPVs 133A) and 62% for Orbis-Sigma valves (OSVs), 130) suggesting a slight superiority in efficacy of CHPVs. The incidence of shunt obstruction ranged from 2% 107) to 30% 133) for CHPVs, 4% for SVs, 104) 5% for the dualswitch valves  (DSVs; B Braun, Germany), 107) and 10% for the DPVs. 69A) Although it is difficult to make a direct comparison of these valves due to differences in the observation period, in general, there seemed to be no differences between them.…”