A novel modification for removal of the polyethylene core in artificial disc retrieval using a transpsoas minimally invasive technique.

Total disc replacement (TDR) surgeries have significantly increased in number since US FDA approval. However, the associated complications such as implant malposition, loosening, subsidence, implant migration, fractures, and infection may necessitate retrieval of the artificial disc and proceeding with interbody fusion. Retrieval of artificial discs in proximity to important vascular, urological, and other vital anatomical structures (for example, L4-5) presents numerous difficulties to spine and approach surgeons. To avoid the impediments of an anterior revision approach, in 2006 Pimenta et al. described an effective transpsoas lateral minimally invasive approach to retrieve the TDR device. In this paper, the authors adopted this technique in their surgical practice; however, they realized that a complex step involved the removal of the polyethylene core. The polyethylene core is compressed between the device endplates and is difficult to remove with the aid of a Kocher clamp as advised by Pimenta et al. Moreover, distraction on the endplates or the vertebral bodies to decrease the compression across the core is laborious, time consuming, and often not possible due to the approach and location of the lumbar plexus. In the present paper, the authors propose a novel modification to the polyethylene core removal with the use of a screw to create a better lever arm, apply effective distraction, and secure a good grip to enable core retrieval. This modification significantly reduced the operating time.