Correlation of 2-year SRS-22r and ODI patient-reported outcomes with 5-year patient-reported outcomes after complex spinal fusion: a 5-year single-institution study of 118 patients

OBJECTIVE Patient-reported outcomes (PROs) are often measured up to 2 years after surgery; however, prospective collection of longitudinal outcomes for 5 years postoperatively can be challenging due to lack of patient follow-up. The aim of this study was to determine whether PROs collected at 2-year follow-up accurately predict long-term PROs 5 years after complex spinal fusion (>= 5 levels). METHODS This was an ambispective study of 118 adult patients (>= 18 years old) undergoing >= 5-level spinal arthrodesis to the sacrum with iliac fixation from January 2002 to December 2011. Patient demographics and radiographic parameters as well as intraoperative variables were collected. PRO instruments (Scoliosis Research Society [SRS]-22r function, self-image, mental health, pain, and Oswestry Disability Index [ODI]) were completed before surgery then at 2 and 5 years after surgery. Primary outcome investigated in this study was the correlation between SRS-22r domains and ODI collected at 2- and 5-year follow-up. RESULTS Of the 118 patients, 111 patients had baseline PROs, 105 patients had 2-year follow-up data, and 91 patients had 5-year follow-up PRO data with 72% undergoing revision surgery. The average pre- and postoperative major coronal curve Cobb angles for the cohort were 32.1 degrees +/- 23.7 degrees and 19.8 degrees +/- 19.3 degrees, respectively. There was a strong correlation between 2- and 5-year ODI (r(2) = 0.80, p < 0.001) and between 2- and 5-year SRS-22r domains, including function (r2 = 0.79, p < 0.001), self-image (r(2) = 0.82, p < 0.001), mental health (r2 = 0.77, p < 0.001), and pain (r2 = 0.79, p < 0.001). Of the PROs, ODI showed the greatest absolute change from baseline to 2- and 5-year follow-up (2-year Delta 17.6 +/- 15.9; 5-year Delta 16.5 +/- 19.9) followed by SRS-22r self-image (2-year Delta 1.4 +/- 0.96; 5-year Delta 1.3 +/- 1.0), pain (2-year Delta 0.94 +/- 0.97; 5-year Delta 0.80 +/- 1.0), function (2-year Delta 0.60 +/- 0.62; 5-year Delta 0.49 +/- 0.79), and mental health (2-year Delta 0.49 +/- 0.77; 5-year Delta 0.38 +/- 0.84). CONCLUSIONS Patient-reported outcomes collected at 2-year follow-up may accurately predict long-term PROs (5-year follow-up).