To the Editor:
The Patil stereotactic system (Ortho Development Corp., Draper, UT) is one of the most widely used stereotactic frames in neurosurgical practice. In a recent operation at our center, significant damage was sustained to the base unit of the system during a computed tomography-guided stereotactic biopsy. We hereby warn Neurosurgery readers of the possibility of an accident while using the system.
A 61-year-old man was scheduled to undergo a stereotactic brain biopsy of an enhanced lesion near the right posterior horn. After the fixation of the patient’s head in the Watts headholder, the patient’s head was suddenly jolted out of position. An inspection of the fixation device revealed that the cranial pinholder, which is made of polyoxymethylene, had broken at the clamping part (Fig. C1). The operation was discontinued, and the procedure was postponed because we did not have spare parts to repair the device.
We have used this Patil head frame in several hundred operations during the course of 11 years, 4 months. The parts of the system are sterilized by ethylene oxide gas, never by an autoclave. One month before the above-described incident, we used the system for the evacuation of a hypertensive putaminal hematoma, which was performed uneventfully. Although no crack or discoloring of the holder component was observed at the time of preoperative inspection, the surgeon thought that the connection between the pinholder and the head frame was less solid than usual at the beginning of the procedure. The broken part of the holder seems to sustain a shearing force when the patient’s head is fixed. This mechanical force might have resulted in excessive material fatigue of this part because of repeated use.
Fortunately, the patient experienced no complications because of this accident. Although three pins were theoretically enough to maintain the patient’s head in a stable position, we found that the fixation was insufficient and abandoned the procedure. It was extremely lucky that the accident happened at the very beginning of the procedure. If the apparatus had broken during the insertion of the biopsy needle, parenchymal or vascular damage of the brain would have been inevitable.
Ideally, a head-supporting system should have a safety mechanism by which the head is kept supported even if part of the device is broken. At present, however, such a system is not available. According to the Japanese distributor of the product (Japan Medical Dynamic Marketing, Inc., Tokyo, Japan), a more recent model of the Patil stereotactic system (post-1998) has a revised headholder that uses pinholders without any notches. However, the original models are still widely distributed and used. To avoid such an accident, we recommend careful inspection of the clamping parts before and during each procedure. It also would be advisable to keep a few spare parts in the operating room inventory.