Human Growth Hormone Transgene Expression Increases the Biomechanical Structural Properties of Mouse Vertebrae
Brian Steinke, Avinash G. Patwardhan, Robert M. Havey, and Donna King

Compression tests were performed on individual caudal vertebrae harvested from male and female mice from two transgenic lines expressing an erythroid-specific human growth hormone transgene construct, and their nontransgenic controls. Erythroid-specific production of human growth hormone in transgenic mice resulted in significant increases in biomechanical properties of their caudal vertebrae in compression.

Measurement of Strain Distributions Within Vertebral Body Sections by Texture Correlation
Brian K. Bay, Scott A. Yerby, Robert F. McLain, and Eiren Toh

Quantification of strains within vertebral bodies is central to understanding spinal failures. A technique is described for the measurement of strain distributions within vertebral body samples by correlation of digitized contact radiographs. The mechanical behavior of thoracic spine samples during sample failure and after removal of load is characterized.

Posterior Stabilization of Degenerative Lumbar Spondylolisthesis With a Leeds-Keio Artificial Ligament: A Biomechanical Analysis in a Porcine Vertebral Model
Kanae Suzuki, Joji Mochida, Masahiro Chiba, and Hisao Kikugawa

This report describes a biomechanical model of stabilizing degenerative lumbar spondylolisthesis (DS) with a nonrigid, Leeds-Keio artificial ligament. This system is effective in initially stabilizing an unstable DS model and maintains its stabilizing effect during cyclic loading.

The Production of Scoliosis After Pinealectomy in Young Chickens, Rats, and Hamsters
Cian O'Kelly, Xiaoping Wang, James Raso, Marc Moreau, James Mahood, Jie Zhao, and Keith Bagnall

Pinealectomy in young chickens consistently resulted in scoliosis with many characteristics similar to those seen in patients with adolescent idiopathic scoliosis. Pinealectomy in young rats and hamsters, which are more closely related to humans, did not result in a similar development of scoliosis. The results of this study also suggest that an indication of future scoliosis development among pinealectomized chickens might be a significant increase in size.

Differentiating Lumbar Disc Protrusions, Disc Bulges, and Discs With Normal Contour but Abnormal Signal Intensity: Magnetic Resonance Imaging With Discographic Correlations
Pierre C. Milette, Suzanne Fontaine, Luigi Lepanto, Étienne Cardinal, and Guy Breton

The correlation of magnetic resonance imaging and discography in patients with chronic low back pain indicates that abnormal disc height or signal intensity is highly predictive of symptomatic anular tears. Disc bulges and disc protrusions do not represent discs with significantly different internal architecture, based on the findings of discography, and are no more suggestive of symptomatic tears than discs showing normal contour but decreased height or abnormal signal intensity.

Trunk Muscle Weakness as a Risk Factor for Low Back Pain: A 5-Year Prospective Study
Joon-Hee Lee, Yuichi Hoshino, Kozo Nakamura, Yusei Kariya, Kazuo Saita, and Kuniomi Ito

This 5-year prospective study investigated the role of trunk muscle weakness as a risk factor for low back pain in asymptomatic volunteers. The ratio of peak torque in extension to flexion of the volunteers who had experienced low back pain demonstrated a significantly lower value than that of the volunteers with no history of low back pain.

The Effect of Operative Position and Short-Segment Fusion on Maintenance of Sagittal Alignment of the Lumbar Spine
Clifford B. Tribus, Theodore A. Belanger, and Thomas A. Zdeblick

A retrospective radiographic assessment was done of the maintenance of sagittal alignment in patients undergoing short-segment instrumented fusions in a knee-chest position. Results showed that overall lumbar lordosis is well maintained in patients undergoing short-segment instrumented fusion in the keeling position.

Lymphangioma Presenting as a Dumbbell Tumor in the Epidural Space of the Lumbar Spine
Taichi Saito, Kazumasa Terada, Kuniyoshi Tsuchiya, Yoshinao Oda, Masazumi Tsuneyoshi, and Yukihide Iwamoto

The first case of cavernous lymphangioma presenting as a dumbbell tumor in the epidural space of the lumbar spine is reported. The etiology and pathogenesis of such a tumor are discussed.

The Solitary Intraspinal Vertebral Osteochondroma: An Unusual Cause of Compressive Myelopathy: Features and Literature Review
Anil Khosla, David S. Martin, and Eric E. Awwad

Four previously unreported cases of spinal cord compression by an isolated osteochondroma of the spinal canal are added to the 37 cases previously published in the English language medical literature. Magnetic resonance imaging was useful in localizing the lesion, whereas computed tomography provided more specificity. Surgical intervention led to improvement in most cases.

Whiplash Injury: Biomechanical Experimentation
Narayan Yoganandan, Frank A. Pintar, and Michael Kleinberger

The authors discuss laboratory investigations of the biomechanics of whiplash. Rear-end vehicular crashes are a major source of this trauma. Although previous investigations have examined real-world rear impact-induced whiplash trauma, no general consensus exists, and potentially conflicting conclusions have been drawn on the mechanism of injury. The authors have focused on dynamic human cadaver specimen experiemental studies to analyze the dynamic biomechanics. Results of initial experimentation delineating the mechanisms of headache and neck pain, the two most common symptoms in whiplash, are presented. Critical issues in the design of experimental protocols including model development, instrumentation, dynamic load application, data acquisition principles, and analyses are emphasized.

A Review and Methodologic Critique of the Literature Refuting Whiplash Syndrome
Michael D. Freeman, Arthur C. Croft, Annette M. Rossignol, David S. Weaver, and Mark Reiser

The purpose of this study was to evaluate the methodology of the literature refuting whiplash syndrome. More than 2000 articles in the literature on whiplash were reviewed for publications that clearly refuted the validity of whiplash syndrome. This literature search revealed 20 such articles, which subsequently were reviewed for methodologic flaws that may have invalidated their conclusions. All 20 articles were found to have significantly flawed methodology, and it was determined that their conclusions regarding whiplash syndrome were not supported by the research methods used.