Representative dynamic ranges of spinal alignment during gait in patients with mild and severe adult spinal deformities.

Background Context: Surgical correction strategies for adult spinal deformity (ASD) relies heavily on radiographic alignment goals, however, there is often debate regarding degree of correction and how static alignment translates to physical ability in daily life. Kinematic analysis has the potential to improve the concept of ideal spinal alignment by providing clinically meaningful estimates of dynamic changes in spinal alignment during activities of daily life.

Purpose: Estimate representative dynamic ranges of spinal alignment during gait among ASD patients using 3D motion tracking; compare dynamic alignment between mild and severe deformity patients and to healthy adults.

Biomechanics of prophylactic tethering for proximal junctional kyphosis: effects of cyclic loading on tether strength and failure properties.

Study Design: Biomechanical evaluation of woven polyester tethers.

Objectives: To quantify changes in tether elongation, stiffness, and failure characteristics after cyclic loading. Ligamentous augmentation is gaining interest as a technique to prevent proximal junctional kyphosis (PJK) in adult spinal fusions.

Initial Response of Mature, Experienced Runners to Barefoot Running: Transition to Forefoot Strike.

Introduction: Forefoot strike has been advocated for many runners because of the relatively lower impact and push-off forces compared to a heel strike. The purpose of this study was to explore the ability of mature (> 30 years old), experienced runners to transition from a heel foot strike to a forefoot strike when first introduced to barefoot running on a treadmill. We hypothesized: 1) mature runners who heel strike while wearing traditional training shoes would persist in heel striking immediately following a switch to barefoot, 2) mean shoe heel-to-toe drop would be significantly greater in runners who persist in heel striking when running barefoot compared to those who transition to a forefoot strike pattern, and 3) there would be a significant decrease in heel striking in the barefoot condition as running speeds increased.

Effect of Ultrasound Frequency and Treatment Duration on Antibiotic Elution from Polymethylmethacrylate Bone Cement.

Introduction: The objective of this study was to evaluate the effect of ultrasound frequency and treatment duration on antibiotic-impregnated polymethylmethacrylate (PMMA) antibiotic elution rates and mechanical strength.

Methods: Two batches of PMMA were prepared: one with five grams of vancomycin powder and one without. Each batch was divided into two frequency groups: kHz and MHz.

Biomechanics of Prophylactic Tethering for Proximal Junctional Kyphosis: Comparison of Posterior Tether Looping Techniques.

Study Design: Biomechanical study.

Objectives: Compare effects of four spinous process (SP) tether looping methods on segmental flexion range of motion (ROM), intervertebral disc (IVD) pressures, and peak tether forces.

Summary Of Background Data: SP tethering has been gaining interest as a prophylactic technique to prevent PJK caused by ligamentous laxity in ASD corrective surgery.

Biomechanics of Prophylactic Tethering for Proximal Junctional Kyphosis: Characterization of Spinous Process Tether Pretensioning and Pull-Out Force.

Study Design: Biomechanical evaluation of cadaver functional spinal units (FSUs).

Objectives: Demonstrate the effect of increasing spinous process (SP) tether pretension on FSU flexion range of motion (ROM), intervertebral disc (IVD) pressure, and SP force. Quantify SP tether pull-out forces and relate them to SP forces generated at maximum flexion.