Address of correspondence: Mumbai Spine Scoliosis and Disc Replacement Centre.Bombay Hospital, Mumbai
Objective:The aim of the current study is to critically assess if cross-links are necessary adjuvants in posterior spinal-constructs its cost effectiveness and time utility in its usage.Materials and Methods:The spinal-constructs of patients of varied etiology that underwent surgery between July-2007 and July-2011 without the usage of cross-links were evaluated. The thoracic, lumbar, thoraco-lumbar and cervico-thoracic cases were included and pure cervical cases were excluded from the study. The immediate post-operative erect-radiographs were compared with the erect radiographs at the last follow-up by two independent observers critically for any rotational instability using the Nash-Moe technique11 of assessment of vertebral rotation as well as for ‘parallelogram effect’/ quadrilateral shift. The pedicles which were instrumented were assessed for any change in rotation in immediate post-operative and post-operative radiographs at the last follow up. Any radiograph in which the pedicle outline could not be visibly delineatedbecause of the presence of the pedicle screw was excluded from the study. If the pedicles at the apical vertebra were not well-delineated, the end vertebrae were selected for analysis of rotation. The rotations were graded as per the Nash-Moe technique. The radiographs were also evaluated for fusion, implant loosening breakage and any new deformity. The company representatives of local (domestic) and foreign implant manufacturing companies were contacted to provide information regarding the annual usage and the cost of the respective cross-links.
Total 208 cases were included in this study where in total 707 motion segments are fused. The average follow-up was 15 months (12 months to 36 months).There was no change of rotation between immediate post-operative radiograph and last follow up radiograph. Similarly, there was no ‘parallelogram’ effect’ observed on last follow up radiograph compared to immediate post-operative radiograph. The intra-observer reliability was 100 %. There was no change in the rotation of the levels evaluated by either observer. The inter-observer reliability was 92.83%. This variability was in assessing the grade of vertebral rotation only. None of the levels had a change in rotation irrespective of variation in grade assessment in the final post-op radiograph. There were no pseudo-arthroses or implant breakages. There was no new deformity observed in any of the radiographs at the last follow-up as compared to the immediate post-operative radiographs. We collected data regarding approximate number of cross-links used over a period of one year, from some of these companies. We found that roughly 3764 crosslinks were used all over the country. We calculated the approximate cost of
these, according to the cost per cross-link for individual companies. The final figure obtained was 3.36crore rupees, a significantly high number, considering health related expenditure.
This study shows that the usage of cross-links can be eliminated from clinical practice. The derivations from biomechanical studies do not translate into clinical advantages. Posterior spinal-constructs without cross-links provide stability in all planes in most clinical situations. Eliminating the usage of cross-links reduces the operative time as well as the over-all total hospital costs. Additionally, prominence of implants, corrosion, infection, implant failure and pseudo-arthrosis are the other complications attributed to cross-links in the literature that can be eliminated.
How to Cite this Abstract
Pisal T, Bhute N, Patil V, Kulkarni A. Cross Links’ in Spine: Cost effectiveness and Time Utility in its usage. International Journal of Conference Proceedings 2015;(2015):59