Biomedical subjects

Geoffrey N Askin

Publications and source records attributed to Geoffrey N Askin.

5 recordsLinked to original sources

PubMed2006

Recovery of pulmonary function following endoscopic anterior scoliosis correction: evaluation at 3, 6, 12, and 24 months after surgery.

STUDY DESIGN: A series of patients with scoliosis undergoing endoscopic anterior instrumentation and fusion undertaking repeated pulmonary function assessments. OBJECTIVE: To assess recovery of pulmonary function in the 2 years following endoscopic anterior scoliosis correction. SUMMARY OF BACKGROUND DATA: Recent studies have found that pulmonary function returns to preoperative levels 12-24 months following endoscopic anterior scoliosis correction, and a small improvement in forced expiratory volume (FEV1) has also been reported. METHODS: A series of 44 patients with endoscopic anterior scoliosis correction had pulmonary function tests before surgery, and at 3, 6, 12, and 24 months after surgery. Forced vital capacity (FVC), FEV1, and total lung capacity (TLC) were measured. Nonparametric statistical analysis was used to investigate changes in pulmonary function between successive assessments. RESULTS: Pulmonary function decreased by approximately 10% at 3 months after surgery. At 24 months after surgery, FVC and FEV1 recovered to 5% to 8% higher than preoperative levels, while TLC returned to preoperative levels. Statistically significant improvements in most pulmonary function values occurred between 3 and 6, and 6-12 months. Improvements in mean FVC, FEV1, and TLC continue between 12 and 24 months, although only the increase in absolute FVC for this time is statistically significant. CONCLUSIONS: Endoscopic anterior scoliosis surgery has no lasting negative effect on pulmonary function, and with prolonged follow-up, pulmonary capacity improves beyond preoperative levels.

Adolescent↗

PubMed2006

A prospective assessment of SRS-24 scores after endoscopic anterior instrumentation for scoliosis.

STUDY DESIGN: Prospective clinical case series. OBJECTIVE: To evaluate the clinical outcome of anterior endoscopic instrumention for scoliosis using the SRS-24 questionnaire and to examine how these scores change over a 2-year follow-up period. SUMMARY OF BACKGROUND DATA: Anterior endoscopic instrumentation correction has several advantages compared with open procedures. However, the clinical results of this technique using a validated outcome measure have rarely been reported in the literature. METHODS: A total of 83 consecutive patients underwent endoscopic anterior instrumentation performed at a single unit. Patients completed the SRS-24 questionnaire before surgery and at 3, 6, 12, and 24 months after surgery. The SRS-24 scores were compared between each of the follow-up intervals. RESULTS: The pain, general self-image, and function from back condition domains improved after surgery (P < 0.05). Activity level significantly improved between 3 and 6 months, and both function domains improved between 6 and 12 months (P < 0.05). None of the domains increased significantly after 1 year. CONCLUSIONS: Endoscopic anterior instrumentation for scoliosis significantly improved pain, self-image, and function. The greatest improvement in function occurred between 6 and 12 months after surgery. The SRS-24 scores at 1 year from surgery may provide a good indicator of patient outcome in the long-term.

Adolescent↗

PubMed2006

Automatic measurement of vertebral rotation in idiopathic scoliosis.

STUDY DESIGN: Development of an automatic measurement algorithm and comparison with manual measurement methods. OBJECTIVES: To develop a new computer-based method for automatic measurement of vertebral rotation in idiopathic scoliosis from computed tomography images and to compare the automatic method with two manual measurement techniques. SUMMARY OF BACKGROUND DATA: Techniques have been developed for vertebral rotation measurement in idiopathic scoliosis using plain radiographs, computed tomography, or magnetic resonance images. All of these techniques require manual selection of landmark points and are therefore subject to interobserver and intraobserver error. METHODS: We developed a new method for automatic measurement of vertebral rotation in idiopathic scoliosis using a symmetry ratio algorithm. The automatic method provided values comparable with Aaro and Ho's manual measurement methods for a set of 19 transverse computed tomography slices through apical vertebrae, and with Aaro's method for a set of 204 reformatted computed tomography images through vertebral endplates. RESULTS: Confidence intervals (95%) for intraobserver and interobserver variability using manual methods were in the range 5.5 degrees to 7.2 degrees . The mean (+/-SD) difference between automatic and manual rotation measurements for the 19 apical images was -0.5 degrees +/- 3.3 degrees for Aaro's method and 0.7 degrees +/- 3.4 degrees for Ho's method. The mean (+/-SD) difference between automatic and manual rotation measurements for the 204 endplate images was 0.25 degrees +/- 3.8 degrees . CONCLUSIONS: The symmetry ratio algorithm allows automatic measurement of vertebral rotation in idiopathic scoliosis without intraobserver or interobserver error due to landmark point selection.

Algorithms↗

PubMed2005

Variability in Cobb angle measurements using reformatted computerized tomography scans.

STUDY DESIGN: Survey of intraobserver and interobserver measurement variability. OBJECTIVE: To assess the use of reformatted computerized tomography (CT) images for manual measurement of coronal Cobb angles in idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Cobb angle measurements in idiopathic scoliosis are traditionally made from standing radiographs, whereas CT is often used for assessment of vertebral rotation. Correlating Cobb angles from standing radiographs with vertebral rotations from supine CT is problematic because the geometry of the spine changes significantly from standing to supine positions, and 2 different imaging methods are involved. METHODS: We assessed the use of reformatted thoracolumbar CT images for Cobb angle measurement. Preoperative CT of 12 patients with idiopathic scoliosis were used to generate reformatted coronal images. Five observers measured coronal Cobb angles on 3 occasions from each of the images. Intraobserver and interobserver variability associated with Cobb measurement from reformatted CT scans was assessed and compared with previous studies of measurement variability using plain radiographs. RESULTS: For major curves, 95% confidence intervals for intraobserver and interobserver variability were +/-6.6 degrees and +/-7.7 degrees, respectively. For minor curves, the intervals were +/-7.5 degrees and +/-8.2 degrees, respectively. Intraobserver and interobserver technical error of measurement was 2.4 degrees and 2.7 degrees, with reliability coefficients of 88% and 84%, respectively. There was no correlation between measurement variability and curve severity. CONCLUSIONS: Reformatted CT images may be used for manual measurement of coronal Cobb angles in idiopathic scoliosis with similar variability to manual measurement of plain radiographs.

Adolescent↗

PubMed2004

The jigsaw sign. A reliable indicator of congenital aetiology in os odontoideum.

There is evidence in the literature for both a congenital and a post-traumatic aetiology for os odontoideum. In no series published to date has CT been used to aid in the diagnosis. This is a prospective study of the history of trauma and presence of diagnostic features on CT of 18 consecutive cases with os odontoideum. Our objective was to derive clinically useful radiological features enabling accurate differentiation between congenital and post-traumatic aetiologies. A mid-sagittal CT reconstruction of the atlanto-dens joint was obtained. Hypertrophy of the anterior arch of the atlas was quantified by measurement of the arch-peg-area ratio. The presence of dysplastic features (a positive "jigsaw" sign) of the atlanto-axial joint were noted. These included narrowing of the cartilage space and interdigitation of the two joint surfaces. A history of a potential traumatic aetiology was only obtained in one of the 18 (6%) in our series. A significant elevation of the arch-peg ratio was found when comparing this series to 85 controls. And a positive jigsaw sign was observed in 75% of cases. These features were not seen in paediatric cases of atlanto-axial instability, including odontoid non-union. In conclusion, an elevated arch-peg ratio and the presence of a jigsaw sign are sensitive and specific diagnostic criteria for os odontoideum. This series supports a congenital aetiology for this condition.

Adolescent↗