For a retrospective study, researchers wanted to determine if there was a link between adjacent segment degeneration (ASD) and Roussouly type following L4-5 transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis revision surgery rates. After spinal fusion, revision surgery for ASD was known to occur; however, it is unclear whether ASD rates are linked to certain Roussouly types. Patients who had L4-5 TLIF for spondylolisthesis at the University of California San Francisco between January 2006 and December 2016 and had at least a 2-year follow-up were retrospectively examined by Roussouly type. The Roussouly type was used to link revision surgery for ASD. For correlation, spinopelvic parameters were also examined. (P<0.05) was considered significant. About 174 patients met the criteria for participation (59 males and 115 females). The average age was found to be 62.3 (ranging from 25 to 80) years. There were 132 individuals with grade I spondylolisthesis and 42 with grade II spondylolisthesis. The average follow-up time was 45.2 months (range: 24–497). After L4-5 TLIF, 22 patients (12.6%) required revision surgery for ASD. Revision surgery rates for ASD were 1, 14.3%, 2, 22.6%, 3, 4.9%, and 4, 15.6% (P=0.013) when classified by Roussouly type. The lowest revision surgery rate (4.9%) was found in type 3 spines with normal PI-LL (8.85° ± 6.83°), whereas the highest revision surgery rate (22.6%) was found in type 2 spines with PI-LL mismatch (11.06° ± 8.81°), a four-fold difference (P=0.013). The PI-LL mismatch in each type did not alter significantly after surgery (P>0.05). The researchers discovered a link between Roussouly type and revision surgery for ASD after L4-5 TLIF for spondylolisthesis, with type 2 spines having the greatest rate of revision surgery for ASD. Spinopelvic characteristics could be linked to ASD revision surgery after L4-5 TLIF.
