Clinical Results from Subsidence and Loss of Lordosis after Anterior Cervical Discectomy and Fusion

OBJECT: The aim of this study is to analyze the statistical significance between the clinical result and subsidence and lordosis loss after anterior cervical discectomy and interbody fusion operation for degenerative cervical disc diseases. METHODS: From January 2004 to December 2006, retrospective study of 82 patients with symptomatic degenerative cervical disc disease who underwent anterior cervical discectomy and interbody fusion using the PEEK SolisTM cage and the carbon composite Osta-PekTM cage with autologous bone graft was done. Mean follow-up period was 13.2 months. Clinical results were assessed by bone fusion, subsidence, segmental lordosis loss and Odom's criteria. RESULTS: Of the 82 patients, single level fusion was accomplished in 67 patients and two-level fusion in 15 patients. Total accomplished fusion level was 97: C3/4 in 9 levels, C4/5 in 29 levels, C5/6 in 37 levels, C6/7 in 21 levels, C7/T1 in 1 level. 9 patients fit into complete resolved, 59 improved and 14 not changed, thus the success rate in clinical outcome was 82.9%. Bone fusion was successfully confirmed in the total of 82 patients. The height of disc space was decreased to 2.13+/-2.16mm: 2.64+/-1.81mm in the Osta-PekTM cage, 2.44+/-1.36mm in the PEEK SolisTM cage. The Osta-PekTM cage provided higher subsidence tendency than the PEEK SolisTM cage in our study. However, there was no statistical significance between the two cage groups. The subsidence and lordosis loss showed poor clinical outcome, but there was no statistical significance. CONCLUSIONS: There were no significant differences between the Osta-PekTM cage and PEEK SolisTM cage on clinical outco mes. Both cages showed low subsidences and lordosis loss with good fusion rate and clinical outcome.

A Clinical Study of Intraocular Lens Power Calculation

Intraocular lens power was calculated from data of axial length, corneal curvature, and anterior chamber depth in 112 eyes which underwent IOL implant surgery. Postoperative refractions of 112 eyes were analyzed into three groups such as the group of which constant A is 116.2, the group of which constant A is 116.8, and TI-59 system group. The results were as follows; 1. The A constant derived from retrograde analysis in our 112 cases was 116.2. In the cases of the constant A 116.2, error of predicted required spectacle lens power was -0.16D +/- 0.89 in relative average, 0.67D +/- 0.57 in absolute average. Using the standard formula described by Hoffer, the accuracy of IOL power calculation by the constant 116.2 was 76.1% +/- 1.0D / 97.4% +/- 2.0D / +2.42 to -2.11D. 2. The specific constant A of intraocular lenses inserted in our hospital was 116.8. In the cases of the constant A 116.8, error of predicted required spectacle lens power was -0.39D +/- 0.88 in relative average, 0.75D +/- 0.60 in absolute average. Using the standard formula described by Hoffer, the accuracy of IOL power calculated by the constant A 116.8 was 72% +/- 1.0D / 96% +/- 2.0D / +2.34 to -2,50D. 3. In TI-59 system of IOL power calculation, error of predicted required spectacle lens power was -0.12D +/- 1.0D in relative average and 0.75D +/- 0.66 in absolute average. Using the staudard formula described by Hoffer, the accuracy of IOL power calculation in this method was 73% +/- 1.0D / 91.5% +/- 2.0D / +2.77 to -2.31D. 4. There was a significant difference between the error of the A constant 116.2 and that of 116.8(P. 0.05), but wasn't between the error of the A constant 116.2 and that of TI-59 system. 5. In the case of axial length 21mm +/- 0.5, the IOL power calculation by the A constant 116.2 was the most accurate among three groups.