Transforaminal lumbar interbody fusion (TLIF) has been the “workhorse” spinal procedure for the past decade. However, there remains the challenge of suboptimal lordotic interbody cage placement. A group of researchers have proposed that adjustment of spinopelvic parameters play an important role in outcome following TLIF.
Winner of the Stewart B Dunsker, MD, Award, Karthik Madhavan (Miami, USA), presented his team’s research on the topic during the 2017 American Association of Neurological Surgeons (AANS; 22–26 April, Los Angeles, USA) annual scientific meeting.
The team retrospectively reviewed 730 patients who underwent TLIF surgery. Standing X-rays were assessed for changes in disc height, lumbar lordosis, pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). Reoperation rate was also assessed.
These 730 operations were performed at more than 1,000 levels. Among the 90 patients with kyphosis (12.3%), 45% had restoration of lordosis. Interestingly, among those with normal lordosis, 57% developed kyphosis postoperatively. High PT, SS and PI)were observed in 57%, 8.5% and 24% respectively. However, only 32.1% and 60% of these patients with high PT and SS were successfully corrected with TLIFs while the high PI was remained unchanged, as expected. The reoperation rate was 4.1% and reasons included adjacent segment disease and pseudoarthrosis.
Several factors influence sagittal balance post-TLIF including inherent lordosis of the cage, the expandable nature, anterior position of cage and compression of posterior screws. Spino-pelvic parameters are the foundation of spinal correction and any insufficient correction could lead to a situation where the upper body gradually kyphoses forward.