If the inline PDF is not rendering correctly, you can download the PDF file here.
To The Editor: We read with great interest the paper on intraoperative complications of cranial perforators by Vogel et al.1 (Vogel TW, Dlouhy BJ, Howard MA III: Don't take the plunge: avoiding adverse events with cranial perforators. Clinical article. J Neurosurg 115:570–575, September 2011). The authors describe the complications in using cranial perforators during a 2-year period in 1652 cranial procedures. Plunging, defined as “an uncontrolled rapid increase in depth of the cranial perforator or drill,” occurred in 9 procedures (0.54%). This overall complication rate is relatively low, and plunging in these 9 cases did not result in any serious or irreversible damage to the patient.
Trephining the skull is one of the basic skills that must be acquired during neurosurgical training. There are various methods of performing a craniotomy, all starting with 1 or multiple holes.1 These holes can be created using mechanical, electrical, or pneumatic devices, and the size and method of the bur hole vary among the chosen techniques. Multiple aspects must be considered when choosing the method of trephining, including the 1) complications associated with the applied technique, 2) the speed of the technique, 3) the cosmetic result, and 4) cost.
In January 2010, one of the authors (T.M.) switched from using a cranial perforator (such as the one described in the abovementioned study) to a high-speed drill for making bur holes. The rationale for this change was 3-fold: economic, educational, and cosmetic. Concerning the economic issue, a single-use disposable perforator (Codman, Johnson & Johnson) costs around €146 (approximately $195 US) in Belgium. As an alternative, a regular surgical cutting ball drill of 4 mm (Midas Rex, Medtronic) costs around €77 (approximately $103 US) and can be resterilized 8–10 times, reducing the cost to approximately €10 per procedure. The ecomonic burden of using these disposable cranial perforators may seem irrelevant; however, the total cost per year may change views on this subject at a time when economic aspects of general health care costs are of concern. In our clinic, the use of a high-speed drill reduced the cost for craniotomies and bur hole procedures (for 1 surgeon performing around 200 bur holes and craniotomies together per year) to approximately €18,000 (approximately $24,000 US) per year.
Considerations other than cost, namely educational and cosmetic, may also motivate the more routine use of a high-speed drill for trephining the skull. If residents are consequently trained to drill bur holes with a high-speed drill in a relatively safe area, such as for ventriculostomy procedures or pterional craniotomies, then they are better prepared to drill and have better control of movements in a more difficult and critical surgical field (for example, drilling the internal acoustic meatus or anterior clinoid process).
Finally, customized drill holes are usually smaller than the regular 11-mm bur hole resulting from the cranial perforator (Fig. 1). A Codman disposable perforator makes bur holes of 9, 11, or 14 mm (depending on the size of the perforator), as compared with the 5- to 7-mm bur holes made using the high-speed drill. Bur holes in the frontal area especially can give disappointing cosmetic results, and decreasing the size of the bur hole may give superior cosmetic results after the craniotomy. Moreover, the bur hole can be adapted to the scheduled craniotomy, for example, extending the bur hole in a curvature (Fig. 2) or drilling in a specific configuration for the placement of extended neuromonitoring probes (Fig. 3).
We realize that making bur holes using a high-speed drill may already be common practice among neurosurgeons and that its use is dependent on local habits and preferences.
In conclusion, it is our opinion that the use of a high-speed drill is a good and cost-effective alternative to the cranial perforator for drilling bur holes. Nevertheless, the authors are to be congratulated for reporting the complication rate for a product routinely used in a neurosurgical practice.
The authors report no conflict of interest.
This article contains some figures that are displayed in color online but in black-and-white in the print edition.