Background: The arachnoid knife is a useful instrument when performing a variety of neurosurgical procedures, for example, while opening the sylvian fissure or basal arachnoid bridges in the pterional approach or during the peripheral delimitation and excision of a cortical AVM. At present, there exists a wide variety of arachnoid knives made from different materials (stainless steel, titanium, or diamond-tipped); however, most of these instruments are expensive and may become dull with continuous use or bad handling.
Methods: In this article, we report the use and advantages of an arachnoid knife from a simple hypodermic needle.
Results: In the last 6 years, we have used this technique to open the arachnoid layer in more than 350 neurosurgical procedures. Furthermore, it can be used to perform sharp arteriotomies during bypass procedures or to open the dura mater over bone structures. To date, no complication arising from this simple technique has been documented.
Conclusions: A standard hypodermic needle can be used in the operating room as a practical arachnoid knife. It has the characteristics of being effective, low-cost, and available worldwide.