Cranial Flap Fixation Clamps and Similar Devices

After performing a craniotomy, bone flaps are typically fixed with wire, suture material, or small plates and screws. Problems related to cranial bone flap fixation after craniotomy are more common with the trend for performing smaller craniotomies that are frequently utilized for minimally invasive surgical procedures. The use of small plates and screws for fixation of cranial bone flaps has improved the overall attachment process and end result. However, this technique requires a considerable amount of time and expense compared to using wire and suture techniques.

In consideration of the various problems with bone flap fixation, a special metallic implant system, named the Craniofix (Aesculap, Inc., Central Valley, PA) was developed for fixation of cranial bone flaps after craniotomy. MR tests conducted to assess magnetic field interaction, heating, and artifacts indicated that the clamps used for the cranial bone flap fixation system present no risk to the patient in the MR environment of MR systems operating at 1.5-Tesla or less.

Furthermore, the quality of the diagnostic MR images was acceptable, particularly for conventional spin echo or fast spin echo pulse sequences. Other devices used for similar applications have also been evaluated MR related issues.

MRI Information at 3-Tesla and Cranial Fixation Implants and Devices.
MRI at 3-Tesla and Cranial Fixation Implants and Devices. Several different cranial or burr hole fixation implants and devices made from titanium or titanium alloy have been tested at 3-Tesla. These were found to be acceptable for patients undergoing MRI procedures.

CranioFix Titanium Clamps (Information dated 11/11/09 - Aesculap Inc., Center Valley, PA) are indicated for the fixation of cranial bone flaps after a craniotomy. They are manufactured from a titanium alloy (Ti6Al4V) which is non-ferromagnetic and may be safely exposed to MRI. All CranioFix Titanium Clamps (FF099T, FF100T, FF101T, FF490T, FF491T, and FF492T) have been tested and proven MR-safe per ASTM-2052-02* up to 3.0 Tesla.

For additional information, please refer to the following publications:
(1) Shellock, F.G. (2009). Reference manual for MR safety, implants, and devices. Los Angeles: Biomedical Research Publishing Group.
(2) Shellock, F.G. (2002). Biomedical implants and devices: Assessment of magnetic field interactions with a 3.0 Tesla MR system. JMRI, 16, 721-732

*These Aesculap devices were cleared by FDA as “MR-Safe” per ASTM-2052-02. Due to a change in definition within this standard, F 2503-2005-08, these devices are now termed as “MR Conditional” by ASTM. The FDA has not mandated a revision to our labeling because the device material and performance have not changed.

REFERENCES

Shellock FG. Biomedical implants and devices: assessment of magnetic field interactions with a 3.0-Tesla MR system. J Magn Reson Imaging 2002;16:721-732.

Shellock FG. Magnetic Resonance Procedures: Health Effects and Safety. CRC Press, LLC, Boca Raton, FL, 2001.

Shellock FG, Kanal E. Magnetic Resonance: Bioeffects, Safety, and Patient Management. Second Edition, Lippincott-Raven Press, New York, 1996.

Shellock FG, Shellock VJ. Evaluation of cranial flap fixation clamps for compatibility with MR imaging. Radiology 1998;207:822-825.