Surgical pitfalls of an ultrasonic bone curette (SONOPET) in spinal surgery

OBJECTIVE: We report our experience with the SONOPET ultrasonic bone curette. METHODS: Between September 2001 and July 2005 546 patients underwent micro-scopic spinal surgeries using a high-speed drill and the SONOPET instrument. RESULTS: We encountered operative complications thought to be attributable to the use of the SONOPET in six patients (1.1 %). There were five instances of dural puncture and one spinal cord injury. All dural tears occurred when the dura mater was aspirated into the tip of the SONOPET. None of the affected patients developed postoperative clinical complications because cerebrospinal fluid leakage was avoided by appopriate closure. We think that the transient spinal cord injury occurred, because the vibration emanating from the SONOPET was, transmitted directly to the spinal cord. Some patients experienced damage to the epidural venous plexus for reasons similar to those described above. CONCLUSION: SONOPET facilitates the removal of bone in a narrow field, such as that encountered during keyhole surgery. It aids in the removal of the lateral edge of bone and is especially useful for expanding the foramen intervertebrale or opening the lateral recess. However, its use is not without risk. To prevent dural tears and venous Plexus injury, we recommend that cotton be placed between the SONOPET and important structures. To avoid spinal cord injury, we suggest that the SONOPET be inserted horizontal with the dura mater to avoid the direct transmission of vibrations emanating from the instrument to the spinal cord. SONOPET is suitable for decompression on the lateral side, but not for decompression above the spinal cord.