Development and validation of a quantitative method to assess pedicle screw loosening in posterior spine instrumentation on plain radiographs.

Aghayev, Emin; Zullig, Nicolas; Diel, Peter; Dietrich, Daniel J.; Benneker, Lorin Michael (2014). Development and validation of a quantitative method to assess pedicle screw loosening in posterior spine instrumentation on plain radiographs. European spine journal, 23(3), pp. 689-694. Springer 10.1007/s00586-013-3080-2

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PURPOSE Currently, the diagnosis of pedicle screw (PS) loosening is based on a subjectively assessed halo sign, that is, a radiolucent line around the implant wider than 1 mm in plain radiographs. We aimed at development and validation of a quantitative method to diagnose PS loosening on radiographs. METHODS Between 11/2004 and 1/2010 36 consecutive patients treated with thoraco-lumbar spine fusion with PS instrumentation without PS loosening were compared with 37 other patients who developed a clinically manifesting PS loosening. Three different angles were measured and compared regarding their capability to discriminate the loosened PS over the postoperative course. The inter-observer invariance was tested and a receiver operating characteristics curve analysis was performed. RESULTS The angle measured between the PS axis and the cranial endplate was significantly different between the early and all later postoperative images. The Spearman correlation coefficient for the measurements of two observers at each postoperative time point ranged between 0.89 at 2 weeks to 0.94 at 2 months and 1 year postoperative. The angle change of 1.9° between immediate postoperative and 6-month postoperative was 75% sensitive and 89% specific for the identification of loosened screws (AUC = 0.82). DISCUSSION The angle between the PS axis and the cranial endplate showed good ability to change in PS loosening. A change of this angle of at least 2° had a relatively high sensitivity and specificity to diagnose screw loosening.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute for Evaluative Research into Orthopaedic Surgery
08 Faculty of Science > Department of Mathematics and Statistics > Institute of Mathematical Statistics and Actuarial Science
04 Faculty of Medicine > Department of Orthopaedic, Plastic and Hand Surgery (DOPH) > Clinic of Orthopaedic Surgery

UniBE Contributor:

Aghayev, Emin; Dietrich, Daniel J. and Benneker, Lorin Michael

Subjects:

600 Technology > 610 Medicine & health
300 Social sciences, sociology & anthropology > 360 Social problems & social services
500 Science > 510 Mathematics

ISSN:

0940-6719

Publisher:

Springer

Language:

English

Submitter:

Stephanie Schmutz

Date Deposited:

13 Jan 2015 14:51

Last Modified:

05 Oct 2015 08:59

Publisher DOI:

10.1007/s00586-013-3080-2

PubMed ID:

24170238

URI:

https://boris.unibe.ch/id/eprint/61632

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