Comparison of Anterior and Posterior Instrumentation for Correction of Adolescent Thoracic Idiopathic Scoliosis
Randal R. Betz, Jürgen Harms, David H. Clements, III, Lawrence G. Lenke, Thomas G. Lowe, Harry L. Shufflebarger, Dezsö Jeszenszky, and Bruno Beeleo

Seventy-eight patients with thoracic idiopathic scoliosis treated with anterior instrumentation were compared with 100 such patients treated with posterior instrumentation. An average of 2.5 distal fusion levels were saved with anterior instrumentation, but there was an unacceptable rate of pseudarthrosis, loss of correction, and rod breakage with the 3.2-mm flexible rod used for this study.

Cervical Flexion, Extension, Protrusion, and Retraction: A Radiographic Segmental Analysis
Nathaniel R. Ordway, Ronald J. Seymour, Ronald G. Donelson, Leonard S. Hojnowski, and W. Thomas Edwards

Cervical spine segmental motion in the sagittal plane was analyzed in an asymptomatic population by using lateral radiographs for four end-range positions: flexion, extension, protrusion, and retraction. Although full cervical flexion and extension have been thought to take all segments to their available extreme of end-range, this was only true for C2-C7. Protrusion and retraction resulted in a larger range of motion for Occiput-C2. The relations between these segmental motions for the various positions may have clinical implications in the conservative management of cervical spine disorders.

Intertester Reliability of a Low Back Pain Classification System
Lynda Wilson, Hamilton Hall, Greg McIntosh, and Tony Melles

The intertester reliability of a system that categorizes patients with back pain into five distinct pain patterns was determined. Agreement on patient classification by independent examiners was 78.9% (kappa 0.61). This pain pattern system uses key elements of the history and examination to classify patients with low back pain.

Mechanisms Explaining the Association Between Low Back Trouble and Deficits in Information Processing: A Controlled Study With Follow-Up
Satu Luoto, Simo Taimela, Heikki Hurri, and Hannu Alaranta

This study was done to find an explanation for the association between slow reaction times and chronic low back trouble. The results supported the hypothesis that chronic low back trouble (i.e., pain, psychological distress, and general disability) hampers the function of short-term memory in a manner that results in slower information processing among patients with chronic low back trouble.

Reliability of the American Medical Association Guides' Model for Measuring Spinal Range of Motion: Its Implication for Whole-Person Impairment Rating
Julie E. Nitschke, Caroline L. Nattrass, Peter B. Disler, Michael J. Chou, and Kathleen T. Ooi

The reliability of the American Medical Association Guides' recommended methods of measuring spinal range of motion was examined. Poor reliability of the measurements was found for both the Second and Fourth Editions of the Guides. The resultant error in impairment rating has broad implications for the assessment of impairment by compensation organizations throughout the world.

The Effects of Prework Functional Screening on Lowering an Employer's Injury Rate, Medical Costs, and Lost Work Days
Deborah W. Nassau

This 10½-year study was implemented in three stages in a metropolitan medical center. Its objective was to help determine an effective tool that can be used by employers to control the severity of back sprain/strains, medical costs, and lost work days.

The Effect of Operative Predictors of Isokinetic Back Muscle Strength in Patients With Low Back Pain
Anne Keller, Johan G. Johansen, Jan Hellesnes, and Jens I. Brox

Trunk muscle strength was tested in 105 patients with chronic low back pain. Multiple regression analysis was performed using muscle strength as the dependent variable and radiologic, psychological, anthropometric, and demographic factors as independent variables. Gender, muscle area, and pain were the most powerful predictors of isokinetic back muscle strength.

Radiologic and Computed Tomography Image Evaluation of Bone Regrowth After Wide Surgical Decompression for Lumbar Stenosis
Pierre Guigui, Eric Barre, Michel Benoist, and Alain Deburge

Twenty-three patients who underwent decompressive surgery for lumbar spinal stenosis with an average follow-up period of 8 years were evaluated retrospectively regarding the degree of bone regrowth at the posterior arch. Bone regrowth in a surgical defect will occur in most patients after posterior decompression. In the current study, the bone regrowth rate was mild and did not affect the clinical outcome.

Neurologic Injury and Recovery in Patients With Burst Fracture of the Thoracolumbar Spine
Nam-Hyun Kim, Hwan-Mo Lee, and In-Mo Chun

A total of 148 patients with burst fractures of the thoracolumbar spine were extensively reviewed retrospectively. Results indicate that disruption of the posterior elements in burst fractures is associated with a high incidence of neurologic deficits observable at first examination and improved neural recovery during the follow-up period.

Postoperative Gas Bubble Foot Drop: A Case Report
Richard B. Raynor and Leslie Saint-Louis

A case of herniated lumbar disc and vacuum disc at the same level is described. Disc excision relieved symptoms, but 10 days later the patient developed a sudden foot drop. Imaging studies showed that the root was compressed by a gas bubble. Six weeks later, the patient's foot drop had disappeared and the gas bubble was no longer seen on magnetic resonance imaging.

Complete Rotational Burst Fracture of the Third Lumbar Vertebra Managed by Posterior Surgery: A Case Report
Richard Chaloupka

A young man with complete rotational burst fracture of the third lumbar vertebra and neural deficit was treated by posterior surgery, which included reduction, decompression, suture of dural sac tears, fusion of damaged structures, and instrumentation. The success of this treatment was documented by comparing radiographs and computed tomography scans obtained before surgery and after fixator removal. The anterior, posterior, and combined surgery techniques are discussed.