On behalf of the executive committee, it is my pleasure to welcome you to the newly redesigned website of the American Society of Spine Radiology! The upcoming year will be an exciting one for the ASSR as we focus upon initiatives to increase membership and meeting attendance, and strive to improve our visibility as a leading educational and scientific society. The ASSR will maintain a close relationship with our parent society, the ASNR, but is my hope that we will move further afield to augment our membership with additional members of the international spine community and its several related societies.

It is appropriate to recognize all of the officers and members of the ASSR who have worked so hard in the past and contributed their efforts to the benefit of this dynamic and growing society. I am hoping again this year for very active participation on the part of the membership through numerous standing and ad hoc committees. In addition to the usual committee responsibilities, I have drafted specific charges with focused goals and strategies for each committee. These charges are by no means entirely exhaustive, and each committee will develop its own strategy as it moves forward to improve and promote our society.

Through generous corporate support, we will be able to continue the highly successful Mentor Awards Program, initiated last year under the direction of Past Presidents Orlando Ortiz and Judith Donovan Post. With additional corporate support, we are planning to initiate the ASSR/ArthroCare Corporation Spine Research Award. This program will allow the ASSR to provide research awards between three and thirty thousand dollars, up to a combined annual total of thirty thousand dollars, to any member of the ASSR in good standing, as well as their mentored medical students, residents and fellows. Awards will be granted and amounts determined based upon review by the ASSR Research Fellowship Committee. We are grateful for the generosity of ArthroCare Corporation, which has made these awards possible, and we encourage applications for this outstanding opportunity to initiate pilot studies or small-scale investigations which might lead to larger grants.

Gregg H. Zoarski, M.D.
President, ASSR

The 2003 ASSR Mentor Award

Jacob Agris, M.D., Ph.D.,
University of Maryland

The overall quality of the scientific paper and poster presentations at the February, 2003 ASSR Symposium in Scottsdale, Arizona was excellent. The ASSR is pleased to announce that Jacob Agris, M.D., Ph.D., is the winner of the 2003 ASSR Mentor Award. Dr. Agris is a fellow in the Division of Diagnostic and Interventional Neuroradiology at the University of Maryland in Baltimore. He and his Mentors, Drs. Ortiz, Stallmeyer, and Zoarski, should be commended for their outstanding work.

Each year, the author presenting the Mentor Award paper receives $1,500 to help pay for travel expenses to the ASSR Symposium. The winning paper is also presented at the American Society of Neuroradiology meeting that same year; the presenting author receives an additional $2,500.00 to help defray ASNR meeting registration and travel expenses. ArthroCare Corporation has generously offered to provide $10,000 annually in order to support the Mentor Program.

Intravertebral Pressure During Vertebroplasty: a Study Comparing Multiple Delivery Systems. Agris JM, Zoarski GH, Stallmeyer MJB. and Ortiz AO*

University of Maryland Medical Center, Baltimore, Maryland, and *Winthrop-University Hospital, Mineola, New York

Purpose:
Vertebroplasty has revolutionized the treatment of compression fractures. Claims of enhanced safety attributable to “low pressure delivery” with larger bore systems are thus far unsubstantiated. We set out to determine whether intravertebral injection pressure measurements differ substantially between various delivery systems and devices. A simple mathematical model representing the different systems by variable resistance predicts that intravertebral pressure should be the same for a constant rate injection no matter which system is used.

Materials & Methods:
A cadaveric model was designed to measure intravertebral pressure during injection of a standardized poly-methylmethacrylate formulation (Secours, ArthroCare Corporation) through three different delivery systems: an 11-gauge (2.3 mm) disposable bone biopsy needle (Cook, Inc., Bloomington, IN), a 6-gauge (4.1 mm) CDO cannula (American Osteomedix, Irvine, CA), and the (4.0 mm) KyphX Inflatable Bone Tamp system (Kyphon, Inc., Sunnyvale, CA). After vertebral access, the tip of a contralateral 11-gauge needle was placed in close proximity to the tip of the device being tested; a pressure transducer was attached to the second needle. Saline flush confirmed continuity across the system. Intravertebral pressures were monitored during administration of 6cc of poly-methylmethacrylate (Secours, ArthroCare Corporation) at a fixed rate of 4cc/min by power injector (Medrad, Inc. Indianola, PA). Finally, measurements were obtained during manual cement delivery using two different delivery cannulas and blunt stylets (AOM and Kyphon), and a hand crank device (EZflow CDS, ArthroCare Corporation).

Results:
Pressure measurements were acquired over a range of 0-500mm Hg (0-9.8atm). The 11-gauge needle system reached a maximum intravertebral pressure (Pmax) of 170mm Hg (3.3psi). The AOM system reached a Pmax of 290mm Hg (5.7psi). Inflation of the KyphX balloon to a maximum of 225psi generated a Pmax of 100mm Hg (2psi); Pmax during subsequent filling of the cavity with poly-methylmethacrylate was 160mm Hg (3.1psi). Manual cement delivery with the Kyphon BFD generated average peak intravertebral pressures of 261mm Hg (5.1psi). Manual delivery with the EZflow CDS system generated a Pmax of 220mm Hg (4.3psi).
Conclusion: Our results demonstrate little difference in Pmax between the 11-gauge needle and the Kyphon balloon system with constant rate cement delivery. In comparison, the larger bore AOM CDO generated a 75% higher peak intravertebral pressure. Manual cement delivery with the EZflow CDS generated a peak intravertebral pressure which was 29% higher than constant rate delivery using the same 11-gauge needle. If a stylet was used for cement delivery with any system, regardless of size, the Pmax exceeded 500mm Hg (9.8psi). The broad conclusion that larger bore systems provide lower intravertebral pressures during cement delivery is incorrect, and operator training remains essential to the safe performance of percutaneous vertebroplasty. As might be expected, all factors influencing cement delivery in a cadaver cannot be predicted by a simple mathematical model. Additional studies using an acrylic vertebral body model will be performed to minimize variability inherent in cadaveric specimens.