Articles from Spine

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Zuhlke, Todd ; Fine, Jason ; Haughton, Victor M.; Anderson, Paul A.
Accuracy of Dynamic Computed Tomography to Calculate Rotation Occurring at Lumbar Spinal Motion Segments
Spine. 34(6):E215-E218, March 15, 2009.
Abstract
Study Design. Reliability study comparing computed tomography (CT) to biomechanics.Objective. To measure the accuracy and precision of such measurements in comparison with a standard method.Summary of Background Data. Rotations of lumbar spinal motion segments can be measured with dynamic CT imaging. This may be a useful tool to measure intersegmental motion. Validation of its use is lacking.Methods. Human cadaveric lumbar spines were fixed in a rigid rotation device and rotated, whereas rotation at each level was measured with extensiometers. Rotation at each level was calculated as a percent of total rotation. The spines were placed in a CT scanner and imaged after rotation of the spine in each direction. The percent of total rotation that occurred at each level was calculated with a software program. Accuracy of the CT method was calculated as the average difference between methods. Precision was measured as the standard deviation of the CT measurement. Biomechanical testing and CT were repeated after the posterior anulus fibrosus at L3-L4 was incised with a scalpel. The power of the CT method to detect a change in rotation was tested by calculating the difference between the pre- and postsurgery rotation at L3-L4 and testing it for significance with a Student t test of paired samples.Results. Differences between CT and biomechanical measurements averaged 0.2%. Precision was 6.0% ( Table 1). Postanular injury, percent rotation at the L3-L4 level increased, whereas it decreased at the other 4 levels. The change at L3-L4 was statistically significant (P = 0.047).(C) 2009 Lippincott Williams & Wilkins, Inc.

Takahashi, Shinobu ; Saruhashi, Yasuo ; Odate, Seiichi ; Matsusue, Yoshitaka ; Morikawa, Shigehiro
Percutaneous Aspiration of Spinal Terminal Ventricle Cysts Using Real-Time Magnetic Resonance Imaging and Navigation
Spine. 34(6):629-634, March 15, 2009.
Abstract
Study Design. Clinical case series.Objective. To present a new innovative treatment option for cysts of the terminal ventricle.Summary of Background Data. Invasive surgery including laminectomy and cyst fenestration has been the sole reported method of treatment for this rare pathology.Methods. Four cases of symptomatic cyst of the terminal ventricle of the spinal cord were treated by percutaneous aspiration using real-time guidance with magnetic resonance imaging (MRI) and optically-tracking navigation.Results. Three patients were treated successfully by this percutaneous method, and for 1 patient the treatment was converted to conventional surgery after a single unsuccessful trial of percutaneous puncture. All patients were relieved of their symptoms without any complication. Follow-up MRI revealed continued shrinkage of the cysts after both surgery and MRI-guided percutaneous fenestration.Conclusion. MRI-navigated percutaneous aspiration can be a minimally-invasive treatment option for symptomatic cysts of the terminal ventricle, and therefore, can be indicated before more invasive surgery might be scheduled.(C) 2009 Lippincott Williams & Wilkins, Inc.

Benz, Becky K. ; Gemery, John M. ; McIntyre, John J. ; Eskey, Clifford J.
Value of Immediate Preprocedure Magnetic Resonance Imaging in Patients Scheduled to Undergo Vertebroplasty or Kyphoplasty
Spine. 34(6):609-612, March 15, 2009.
Abstract
Study Design. Retrospective case series.Objective. To determine the incidence of additional vertebral compression fractures diagnosed with repeat MRI immediately before vertebroplasty or kyphoplasty.Summary of Background Data. Vertebral compression fractures, which occur frequently in the elderly, are more likely in patients with prior vertebral compression fracture. When patients are evaluated for vertebroplasty, it is important to identify all unhealed fractures for effective treatment planning.Methods. In a retrospective study, we reviewed the records of all patients (n = 194) treated with vertebroplasty or kyphoplasty over a 6-year period at our institution, and identified all patients who had undergone a repeat MRI within 7 days of vertebroplasty or kyphoplasty. These studies were obtained as part of a clinical protocol prescribing a repeat MRI for any patient whose MRI had been obtained more than 3 months before the evaluation, or who had a change in their pain between referral and evaluation.Results. Twenty patients met inclusion criteria for the immediate preprocedure MRI protocol. A total of 14 new fractures in 11 patients were discovered on the immediate preprocedure MRI. Of these 14, 6 had less than 15% loss of height, making them potentially occult on radiographs; 3 fractures developed in 2 patients who had no change in back pain.Conclusion. In select candidates for vertebroplasty or kyphoplasty, a repeat preprocedure MRI obtained within 1 week can help ensure that all painful fractures are treated. There is demonstrable value in this protocol for patients with an imaging evaluation over 3 months old or who have had any change in symptoms since the initial imaging workup.(C) 2009 Lippincott Williams & Wilkins, Inc.



Freedman, Brett A. Horton, William C. Rhee, John M. Edwards, Charles C. II Kuklo, Timothy R.
Reliability Analysis for Manual Radiographic Measures of Rotatory Subluxation or Lateral Listhesis in Adult Scoliosis.
Spine. 34(6):603-608, March 15, 2009.
Abstract
Study Design. Retrospective observational study.Objective. To define the inter- and intraobserver reliability of 3 measures of rotatory subluxation (RS) in adult scoliosis (AS).Summary of Background Data. RS is a hallmark of AS. To accurately track this measure, one must know its reliability. Reliability testing has not been performed.Methods. PA 36" films of 29 AS patients were collected from one surgeon's practice. Three observers on 2 separate occasions measured all levels with >=3-mm RS (60 levels, 360 measurements) on the convexity of the involved segment using 3 different techniques-midbody (MB), endplate (EP), and centroid (C). These data were then analyzed to determine the intraclass correlation coefficient (ICC) for inter- and intraobserver reliability.Results. The thoracolumbar/lumbar curve (average 58[degrees]) was the major curve for the majority (62%) of patients. RS at L3/4 was most common (35%). The overall inter- and intraobserver reliability was good-excellent for all methods, but the centroid method consistently had the highest ICC. ICC correlated with observer experience. Moderate-severe arthritic change (present in 55%) and poor image quality (52%) decreased ICC, but it still remained good-excellent for each measure. The reproducibility coefficient for each measure was 4 mm for MB and 2.8 mm for C and EP.Conclusion. MB, EP, and C are reliable techniques to measure RS even in elderly arthritic spines, but the methods inherently produce different values for a given level. The centroid method is most reliable and least influenced by experience. The EP method is easy to perform and very reliable. Spine surgeons should pick their preferred method and apply it consistently. Changes >3 mm suggest RS progression. RS may be a useful measure in addition to Cobb angle in AS. Having defined measurement reliability, the role of RS progression in surgical indications and patient outcomes can be evaluated.