The Amplifier - v. 9, no. 7

In this issue...United States Air Force Academy, ASARCO, Butte Civic Orchestra, International club, IT Club, Montana Oil and Gas Conservation Commision

The Amplifier - v. 9, no. 8

In this issue...Ceramic testing, Bob LeCoure, Butte Civic Center, Rotary Club, Saint Patrick's Day, First-Aid Class, Mine Rescue, Career Day, American Legion Baseball

The Amplifier - v. 9, no. 9

In this issue...computer programming course, Butte Elks Club, IBM, summer jobs, John F. Kennedy, New York World Fair, Butte YMCA, weightlifting, Staghorn Ranch

The Amplifier - v. 9, no. 10

In this issue...Spanish class, Peace Corps, Coast Guard, NASA, Allen Winters, M-Days, Alumni Stadium, Chess Club, Charles Russell, computer class, Columbia Riding Club

The Amplifier - v. 9, no. 11

In this issue...Junior Prom, Blackbird Mining Camp, badminton, Jean Jacques Rousseau, Finlen Hotel, Continental Oil Company, Lee Saperstein, Oceanography

The Amplifier - v. 10, no. 1

In this issue...Homecoming Bonfire, campus interviews, Carol Melvin, Berkeley Pit, Pep Band, Chess Club, Alumni Coliseum, cheerleaders, Theta Tau, Mayor Thomas Powers

The Amplifier - v. 10, no. 2

In this issue...Beryllium, computer center, NASA, Democrats Club, football, Intramural Sports, Women's News, Fall tea, Bob Toivonen, Mineral Club, Miner's Bank

The Amplifier - v. 10, no. 3

In this issue...Hilbilly Hop, Thanksgiving, Dorothy Nile, student elections, Glee Club, Chemical Rubber Company, Victor Burt, student employees, Montana Coal Symposium

The Amplifier - v. 10, no. 4

In this issue...Berkeley Pit, parking permit, Christmas Formal, NASA, Metals Bank, Mrs. Peck, Alumni Coliseum, Park Street, Big M, barrel racing, Sparky McGarry

The Amplifier - v. 10, no. 5

In this issue...YMCA, weightlifting, Mick Hanley, Alumni Coliseum, Mineral Club, Metal's Bank, Father Burns, Montana Power, Senator Frank Reardon, Party Line

The Amplifier - v. 10, no. 6

In this issue...Valentine's Dance, Z-Bar-T, Professor Stolz, registration, Walkerville, E-days, German Club, Herbert Hoover, Oil and Gas Journal, Gregson Hot springs

The Amplifier - v. 10, no. 7

In this issue...Rotary Club, ASARCO, Hootenany, Wesley Club, Ellen Hurlbut, Finlen Hotel, Silver bow County Hospital, Mountain View Church, Butte Post Office

Surgical instrumentation for the in vivo determination of lumbar spinal segment stiffness and viscoelasticity

The definition of spinal instability is still controversial. For this reason, it is essential to better understand the difference in biomechanical behaviour between healthy and degenerated human spinal segments in vivo. A novel computer-assisted instrument was developed with the objective to characterize the biomechanical parameters of the spinal segment. Investigation of the viscoelastic properties as well as the dynamic spinal stiffness was performed during a minimally invasive procedure (microdiscectomy) on five patients. Measurements were performed intraoperatively and the protocol consisted of a dynamic part, where spinal stiffness was computed, and a static part, where force relaxation of the segment under constant elongation was studied. The repeatability of the measurement procedure was demonstrated with five replicated tests. The spinal segment tissues were found to have viscoelastic properties. Preliminary tests confirmed a decrease in stiffness after decompression surgery. Patients with non-relaxed muscles showed higher stiffness and relaxation rate compared to patients with relaxed muscles, which can be explained by the contraction and relaxation reflex of muscles under fast and then static elongation. The results show the usefulness of the biomechanical characterization of the human lumbar spinal segment to improve the understanding of the contribution of individual anatomical structures to spinal stability.