Hydrocephalus shunt procedures

Cerebrospinal fluid (CSF) shunting is one of the most common neurosurgical procedures performed, and has been used for many years with excellent results in the treatment of multiple forms of hydrocephalus in both pediatric and adult patients. However, despite many advances in shunt technology over the years, the rate of shunt failure requiring revision or replacement has remained unacceptably high. This chapter will describe many of the techniques and protocols that can be used to minimize the risk of shunt failure, with a specific focus on the surgical procedure at each anatomic location for proximal and distal catheter placement. Therefore, extended discussions of ventricular and lumbar proximal catheters, and peritoneal, atrial, pleural, and other distal catheters are included. For each shunt location, a description of our preferred surgical protocol is presented, followed by a review of the literature to discuss why we have selected our current protocols. Furthermore, the indications and complications for the different shunt locations will be addressed. Valves Over 100 different shunt valves are currently available from a multitude of manufacturers. Although different valve types and their characteristics will be discussed in detail elsewhere in this publication and have been reviewed in detail previously [1], they can essentially be divided into four different categories: differential pressure valves, flow-regulated valves, antisiphon valves, and adjustable valves. Differential pressure valves allow drainage once a pressure gradient across the valve is established, allowing for a linear correlation of flow rate with intracranial pressure (ICP), which can result in overdrainage in some situations such as coughing or straining that may transiently increase ICP. Flow-regulated valves allow for a constant flow rate with no dependence on ICP, although they generally have a safety mechanism that is activated at very high ICPs when their function converts to that of a differential pressure system. Additionally, flow control valves have increased flow rates with increased distance from the proximal catheter tip, so generally they need to be placed close to above the vertical location of the proximal catheter tip [2].