By Arvind Kulkarni
Crosslinks (traverse connectors) are routinely used as adjuvants in spinal surgery. Although numerous biomechanical studies are available in the literature, there has been no clinical study that has evaluated the need for crosslinks in clinical situations. In India, nearly 3,800 crosslinks are used every year.
My co-authors and I evaluated the spinal constructs of patients of varied aetiology who underwent surgery between July 2007 and July 2011 without the use of crosslinks.
Two independent observers (spinal fellows not involved in the management of the patients) compared the immediate postoperative erect-radiographs with the erect-radiographs at the last follow-up for signs of rotational instability. The intraobserver and interobserver reliability was analysed. The average follow-up was 15 months (12 months to 36 months). None of the cases demonstrated any rotational instability (parallelogram effect) in the follow-up radiographs; the intraobserver reliability was 100%, and the interobserver reliability was 92.83%.
Based on the results of our study (which has been published in Spine), we believe use of crosslinks in clinical practice may be avoidable and that the derivations from biomechanical studies do not translate into clinical advantages. Also, eliminating use of crosslinks could reduce the operating time as well as the overall total hospital costs.
A single crosslink costs anywhere between Indian Rupees (Rs) 5,000 to Rs 20,000, which is an average cost of Rs 10,000 (approximately €127; US$165) per procedure as surgeons tend use more than one crosslink. Therefore, considering nearly 3,800 crosslinks are used in India per year, about Rs 37,65,00,000 could be saved if crosslinks were not used. Also, the average time required to insert a crosslink is about 15 minutes. If the number of crosslinks used per year is multiplied by the average time required to insert one crosslink, then that is a staggering 56,460 minutes—or 941 hours—per year! The amount of time that can be saved by eliminating the use of crosslinks is almost 40 days.
Additionally, prominence of implants, corrosion, infection, implant failure and pseudarthrosis are known complications attributed to crosslinks in the literature. So, the risk of these can be reduced by preventing their incorporation in spinal constructs.
Arvind G Kulkarni is a consultant spine surgeon at Mumbai Spine Scoliosis & Disc Replacement Centre, Bombay Hospital, Mumbai, India